WO2016117543A1

WO2016117543A1 - Vehicle steering system

Info

Publication number: WO2016117543A1
Application number: PCT/JP2016/051407
Authority: WO
Inventors: 晃司清岡; 隆也稲岡
Original assignee: 株式会社神崎高級工機製作所
Priority date: 2015-01-19
Filing date: 2016-01-19
Publication date: 2016-07-28
Also published as: CN107406103A; CN107406103B

Abstract

A vehicle steering system, provided with a side clutch and a side brake in each of a pair of parallel drive trains for distributing power to a pair of axles, and configured so as to cut the side clutch on the inner turning side in accordance with the manipulation of a steering manipulation tool and to operate the side brake, wherein there are provided an auxiliary clutch for varying a joining force in order to transmit a torque between the pair of drive trains, and an auxiliary clutch manipulation tool for increasing the joining force of the auxiliary clutch, and also provided is a restraining mechanism for preventing the operation of the side brake and an increase in the joining force of the auxiliary clutch from being carried out at the same time.

Description

Vehicle steering system

The present invention relates to a side clutch / side brake type vehicle steering system.

Conventionally, as a vehicle steering system applied to a crawler type traveling vehicle (for example, a combine), a side clutch and a side brake are provided in each of a pair of left and right drive trains for distributing power to left and right axles (drive sprocket shafts). A side-clutch / side-brake steering system with a provided configuration is known, for example, as disclosed in Patent Document 1.

As an operation tool of this side clutch / side brake type steering system, for example, a steering lever that can be tilted left and right from a straight traveling position as disclosed in Patent Document 1 is known. By tilting this steering lever to the inside of the turn (to the left if turning left), the side clutch inside the turn is disengaged, the axle inside the turn is decelerated, and the vehicle turns slowly with a large turning radius. If the steering lever is further tilted to the inside of the turn, the side clutch inside the turn will be disengaged, the side brake inside the turn will be applied, the axle on the inside of the turn will be greatly decelerated and then stopped, which will cause the vehicle to turn Make a sharp turn with a small radius (brake turn when the axle inside the turn stops).

JP-A-10-262417

In this side clutch / side brake type vehicle steering system, power is not supplied to the turning inner axle where the side clutch is disengaged. There is a problem that the vehicle may turn with a turning radius smaller than that assumed by the operator because it is easily influenced by the resistance of the surface and road surface (hereinafter referred to as “running resistance”). For example, when tilting the steering lever at a small angle in order to make the vehicle turn slowly, when driving on the dry field, the axle inside the turn with the side clutch disengaged also rotates, as expected. Even if you can make a gentle turn, the running resistance increases when you drive in a wetland, the axle inside the turn with the side clutch disengaged becomes difficult to rotate, the turning radius is smaller than you expected, and the desired large turning radius The vehicle did not turn slowly.

In order to solve this problem, an auxiliary clutch that functions as a limited slip differential mechanism is provided between the left and right axles, that is, between the left and right drive trains described above, and a certain amount of torque is transmitted between the drive trains. In other words, it can be considered that the left and right axles are in a loose diff-lock state. In addition, the engagement force of the auxiliary clutch is made variable so that turning at a desired turning radius can be realized in response to changes in various conditions such as road surface conditions, and the auxiliary clutch is arbitrarily connected according to the judgment at that time by the operator. It is desirable to be operable to adjust the force (ie, the transmission torque between the left and right drive trains).

However, in providing such an auxiliary clutch, the side brake on the inner side of the turn is activated, and the auxiliary clutch is moved from the drive train on the outer side to the drive train on the inner side while the axle on the inner side of the turn is being braked. Since the torque is transmitted through the clutch, durability such as seizure due to frictional heat of the clutch tends to occur. On the other hand, even if the side clutch on the inside of the turn is disconnected, if the side brake on the inside of the turn is operated in a state where torque is transmitted to the drive train on the inside of the turn via the auxiliary clutch, the frictional heat of the side brake on the inside of the turn is still It becomes easy to cause image sticking. As described above, the phenomenon such as seizure related to the durability of the auxiliary clutch and the side brake, which may occur when the auxiliary clutch is engaged and the side brake is operated at the same time, increases as the engaging force of the auxiliary clutch increases (that is, The larger the amount of transmission torque, the more pronounced it becomes.

An object of the present invention is to provide a side clutch / side brake type vehicle steering system configured to solve the above problems.

A vehicle steering system according to the present invention is provided with a side clutch and a side brake in each of a pair of parallel drive trains for distributing power to a pair of axles, and turns according to the operation of the steering operation tool. The inner side clutch is disengaged and the side brake is operated. In this vehicle steering system, an auxiliary clutch for changing the joining force for transmitting torque between the pair of drive trains and an auxiliary clutch operating tool for increasing the joining force of the auxiliary clutch are provided. In addition, a check mechanism is provided to prevent the side brake operation and the increase in the engagement force of the auxiliary clutch from being performed simultaneously.

In the vehicle steering system according to the first aspect of the present invention, the restraining mechanism is configured to operate the steering operation tool when the auxiliary clutch operation tool is operated so as to increase a joining force of the auxiliary clutch. Regardless, the side brake inside the turn is configured not to operate.

In the vehicle steering system according to the first aspect, there is provided auxiliary clutch engagement force setting means for setting the engagement force of the auxiliary clutch to a predetermined value. The auxiliary clutch operating tool is operated to increase the engagement force of the auxiliary clutch from the predetermined value set by the auxiliary clutch engagement force setting means.

In the vehicle steering system according to the second aspect of the present invention, when the steering operation tool is operated so as to operate the side brake on the inside of the turn, the check mechanism is independent of the operation of the auxiliary clutch operation tool. The joining force of the auxiliary clutch is not increased.

In the vehicle steering system according to the second aspect, there is provided auxiliary clutch engagement force setting means for setting the engagement force of the auxiliary clutch to a predetermined value. The auxiliary clutch operating tool is operated to increase the engagement force of the auxiliary clutch from the predetermined value set by the auxiliary clutch engagement force setting means.

The side clutch / side brake type vehicle steering system according to the present invention is a state in which the side clutch is disconnected from the drive train outside the turn in the drive state with the side clutch being engaged through the auxiliary clutch during the turning of the vehicle. By transmitting the torque to the drive train inside the turn, it is possible to avoid an excessive speed reduction of the axle inside the turn on soft ground or the like. Furthermore, by changing the joining force of the auxiliary clutch and adjusting the joining force in response to changes in the soil condition, the turning radius as set regardless of such changes in the soil condition, etc. It is possible to always obtain a turn at. By providing the check mechanism, it is possible to avoid the situation where the operation of the side brake inside the turning and the increase of the joining force of the auxiliary clutch are avoided at the same time, and the durability of the side clutch and the auxiliary clutch can be improved.

The auxiliary clutch operating tool in which the operator impairs the durability of the side clutch or the auxiliary clutch despite the vehicle turning by the operation of the steering operating tool by the check mechanism in the vehicle steering system according to the first aspect. Even if this operation is performed, the operation of the side brake inside the turn is avoided, so that the situation where the side brake is operated while the joining force of the auxiliary clutch is being increased is avoided.

Further, in the vehicle steering system according to the first aspect, by providing the auxiliary clutch engagement force setting means as described above, the operator can operate the auxiliary clutch operation tool to increase the engagement force of the auxiliary clutch. Unless otherwise, the engagement force of the auxiliary clutch is held at a predetermined value set by the auxiliary clutch engagement force setting means, and the engagement force is applied to the drive train inside the turning with the side clutch disengaged. Torque is transmitted from the drive train outside the turn through the auxiliary clutch in the state set to the value, and it is possible to avoid an excessive decrease in the speed of the axle inside the turn on soft ground as described above. When the operator determines that the engagement force of the auxiliary clutch is not the predetermined value set by the auxiliary clutch engagement force setting means based on the state of the soil or the like, the auxiliary clutch operation tool arbitrarily determines the engagement force from the predetermined value. It will be applied as an operating tool for enabling an increase.

On the other hand, despite the state in which the engagement force of the auxiliary clutch is increased by the operation of the auxiliary clutch operating tool by the check mechanism in the vehicle steering system according to the second aspect, the operator can Even if a turning operation is performed to operate the side brake on the inside of the turn that impairs the durability of the side clutch or the auxiliary clutch, an increase in the joining force of the auxiliary clutch is avoided, so the side brake on the inside of the turn is activated. A situation in which the engaging force of the auxiliary clutch increases during the operation is avoided.

Further, in the vehicle steering system according to the second aspect, by providing the auxiliary clutch engagement force setting means as described above, the operator can operate the auxiliary clutch operation tool to increase the engagement force of the auxiliary clutch. Unless otherwise, the engagement force of the auxiliary clutch is held at a predetermined value set by the auxiliary clutch engagement force setting means, and the engagement force is applied to the drive train inside the turning with the side clutch disengaged. Torque is transmitted from the drive train outside the turn through the auxiliary clutch in the state set to the value, and it is possible to avoid an excessive decrease in the speed of the axle inside the turn on soft ground as described above. As long as the turning operation that activates the side brake inside the turning is not performed by the steering operation tool, the auxiliary clutch operating tool has the auxiliary clutch engaging force that is determined from the state of the clutch soil. When the operator determines that the predetermined value set by the setting means is not sufficient, it is applied as an operation tool for arbitrarily increasing the bonding force from the predetermined value.

1 is a skeleton diagram of a transmission 1 to which a vehicle steering system according to the present invention is applied, and a hydraulic circuit diagram of a vehicle steering actuator set 2. FIG. 2 is a plan sectional view of the transmission 1. FIG. 2 is a partial cross-sectional view of a side surface of the transmission 1. FIG. FIG. 3 is an enlarged plan cross-sectional view of a portion that accommodates a side clutch shaft 5 in the transmission 1. 3 is an enlarged plan sectional view of a support portion of an axle 4 to a transmission case 20 in a transmission 1. FIG. FIG. 4 is a rear cross-sectional view of the vehicle steering actuator set 2 in a portion where the

steering actuators

34L and 34R are disposed. FIG. 3 is a rear view of the vehicle steering actuator set 2 and includes a rear sectional view of a relief valve 33. FIG. 4 is a side sectional view of the vehicle steering actuator set 2 and a side sectional view of the relief valve 33. FIG. 3 is a partial perspective view of the transmission 1 showing an embodiment in which a breather is formed at an attachment portion of the vehicle steering actuator set 2 in the transmission case 20. 3 is a rear view of the steering lever 11. FIG. It is a back surface sectional view of steering lever 11 provided with resistance mechanism 170. 6 is a graph showing the relationship between the tilt angle T of the steering lever 11 and the operating resistance R applied to the steering lever 11, which appears by the resistance mechanism 170. FIG. 13A is a rear view of the steering lever 11 provided with the resistance mechanism 180, FIG. 13A is a diagram of the steering lever 11 in the straight advance setting position, and FIG. 13B is a state in which the steering lever 11 is tilted for turning the vehicle. It is a figure of the steering lever 11. FIG. FIG. 3 is a plan sectional view of a portion that houses a side clutch shaft 5 in a transmission 1 that includes a resistance (friction) mechanism 188. 15A is a rear view of the steering lever 11 provided with the resistance mechanism 189, FIG. 15B is a cross-sectional view taken along the line BB in FIG. 15A, and FIG. It is a graph which shows the relationship between the tilting angle T of the steering lever 11 and the operation resistance R applied to the steering lever 11. It is a rear view of the steering lever 11 provided with the check mechanism 18. 3 is a perspective view of a check mechanism 18. FIG. 1 is a diagram showing a first embodiment of a related structure between a check mechanism and an auxiliary clutch operating mechanism, and is a partial plan view of the check mechanism 18 and an auxiliary clutch engagement pressure setting lever (hereinafter referred to as “lever”) 12; A side view of an auxiliary clutch pedal (hereinafter referred to as “pedal”) 13 is shown. It is a figure which shows the 2nd Example about the related structure of the check mechanism and the operation mechanism of an auxiliary clutch, Comprising: The rear view of the steering lever 11 provided with the check mechanism 18A of another form, and the side view of the lever 12 and the pedal 13 Is shown. FIG. 20 is a front view of the lever 12 and the pushing member 81 in FIG. 19. It is a figure which shows the 3rd Example about the related structure of the check mechanism and the operation mechanism of an auxiliary clutch, Comprising: The plane partial sectional view of the check mechanism 18, and the side view of the lever 12 and the pedal 13 are shown. It is a front view of the lever 12 and the arm 82 in FIG. It is a figure which shows 4th Example about the related structure of the check mechanism and the operation mechanism of an auxiliary clutch, Comprising: The plane partial sectional view of the check mechanism 18, and the side view of the lever 12 and the pedal 13 are shown. It is a front view of the lever 12, the arm 82, and the pedal 13 in FIG. It is a figure which shows 5th Example about the related structure of the check mechanism and the operation mechanism of an auxiliary clutch, Comprising: The rear view of the steering lever 11 provided with the check mechanism 18B of another form, and the side view of the pedal 13 are shown. In this state, the steering lever 11 is set to the straight traveling position and the auxiliary clutch engagement pressure is set to the minimum value. It is a rear view of the check mechanism 18B, and is a view showing a state in which the steering lever 11 is tilted to the side clutch disengagement position with the auxiliary clutch engagement pressure being the minimum value. It is a rear view of the check mechanism 18B, and shows a state in which the steering lever 11 is set to a straight traveling position and the auxiliary clutch engagement pressure is increased to a regulation value. It is a rear view of the check mechanism 18B, and is a view of a state in which the steering lever 11 is tilted to the side clutch disengagement position in a state where the auxiliary clutch engagement pressure is increased to a regulation value. FIG. 2 is a skeleton diagram of a transmission 1A as an embodiment of the transmission 1 including an electronic control actuator AA that adjusts the joining pressure of the auxiliary clutch 8. It is a skeleton figure at the time of turning of transmission 1A. It is a side surface partial sectional view of transmission 1A. 3 is a front sectional view of the electric actuator 141. FIG. FIG. 6 is a skeleton diagram of a transmission 1B as another embodiment of the transmission 1 provided with an electronic control actuator AA that adjusts the joining pressure of the auxiliary clutch 8. It is side surface partial sectional drawing of the transmission 1B. 3 is a basic control flowchart of

transmission

1A or 1B by a controller 10. FIG. It is a block diagram which shows the input means to the controller 10 when it is assumed that a parking brake is applied using a side brake. It is a skeleton figure of

transmission

1A or 1B at the time of the parking brake operation. 3 is a control flowchart of the parking brake operation by the controller 10. It is a block diagram which shows the input means to the controller 10 which shall control

transmission

1A or 1B based on the detection of the inclination state of a vehicle. It is a control flowchart figure by the controller 10 of the

transmission

1A or 1B which shall be controlled based on the detection of the inclination state of a vehicle. It is a figure which shows the auxiliary clutch engagement force meter 117 which displays the actual value of the auxiliary clutch engagement force controlled automatically. It is a perspective view of the steering lever 11 provided with an auxiliary clutch engagement force adjustment dial 113A. It is a figure which shows 113 A of auxiliary clutch engagement force adjustment dials when it sees to the axial center direction of the steering lever 11. FIG.

The configuration of the transmission 1 to which the vehicle steering system according to the present invention is applied will be described with reference to FIGS. The transmission 1 includes a transmission case 20 that supports a pair of left and

right axles

4L and 4R (collectively referred to as “axle 4”) arranged on the same axis. The axle 4 is applied as a drive sprocket shaft of a vehicle having a crawler type traveling device such as a combine. The positions and directions of the constituent members and portions in the transmission 1 described below are based on the premise that the longitudinal direction of the axle 4 is the left-right direction of the transmission 1.

As shown in FIG. 3, FIG. 5, etc., the mission case 20 includes a left housing 120L and a right housing 120R (collectively referred to as “housing 120”). As shown in FIG. 2, an input shaft 28 pointing in the left-right direction is supported on the top of the mission case 20. One end of the input shaft 28 protrudes outside the mission case 20. A pulley 28 a is fixed to this one end portion of the input shaft 28. The pulley 28a constitutes a driven pulley of a belt type transmission device for transmitting the output of a prime mover (not shown) such as an engine to the input shaft 28. A transmission (not shown) that is driven by the rotational power of the input shaft 28 is provided in the upper part of the mission case 20. This transmission is, for example, a hydraulic continuously variable transmission. The output of the transmission is transmitted to the distribution gear 22 via the transmission gear train 29.

In the transmission case 20 of the transmission 1, a side clutch shaft 21 extending in the left-right direction parallel to the axle 4 is rotatably supported by the transmission case 20 via a bearing 21a. As shown in FIG. 3, the inner ring of the bearing 21 a is fitted to the outer peripheral surfaces of the left and right ends of the side clutch shaft 21, and the outer ring of the bearing 21 a is fixed to the transmission case 20.

A distribution gear 22 is fixed to the left and right central portions of the side clutch shaft 21. Within the transmission case 20, a pair of

drive trains

3L and 3R (collectively referred to as “drive train 3”) for distributing power from the distribution gear 22 to the pair of left and

right axles

4L and 4R are provided. . In the mission case 20, a pair of left and right extending left and right

intermediate shafts

24L and 24R (collectively referred to as “intermediate shaft 24”) are arranged on the same axial center in the mission case 20 to constitute the left and right drive trains 3L and 3R. Is provided in parallel to the side clutch shaft 21 and the pair of left and

right axles

4L and 4R, and is rotatably supported by the transmission case 20.

The left shifter 5L is on the left side of the side clutch shaft 21 on the left side of the distribution gear 22, and the right shifter 5R is on the right side of the side clutch shaft 21 on the right side of the distribution gear 22, respectively. The left and

right shifters

5L and 5R are collectively referred to as “shifter 5”. Hereinafter, for each shifter 5, the distribution gear 22 side is the inside, and the opposite side to the distribution gear 22 is the outside. A left side gear 23L is formed at the right end of the left shifter 5L, and a right side gear 23R is formed at the left end of the right shifter 5L (the left and right side gears 23L and 23R are collectively referred to as “side gear 23”). . That is, a side gear 23 is formed at the inner end of each shifter 5.

A clutch claw 6a is formed at each of the left and right ends of the distribution gear 22, and a clutch claw 6b is formed at the inner ends of the side gears 23L and 23R of the left and

right shifters

5L and 5R. In this way, the clutch pawl 6a at the left end portion of the distribution gear 22 and the clutch pawl 6b of the left side clutch 23L form a meshing left side clutch 6L, and the clutch pawl 6a at the right end portion of the distribution gear 22 and the right side clutch 23R. The clutch pawl 6b constitutes a meshing right side clutch 6R (the left and

right side clutches

6L and 6R are collectively referred to as “side clutch 6”).

A pair of left and right springs 5 a are wound around the left and right ends of the side clutch shaft 21, and each shifter 5 is biased toward the distribution gear 22 by each spring 5 a. That is, each spring 5a is biased in the direction in which each side clutch 6 is connected. The outer end of each shifter 5 outside the bush 5d has a cylindrical shape and is arranged around each spring 5a. Also, as shown in FIG. 4, each side clutch shaft 21 is provided with a thrust washer 5 b as a spring receiver that receives the inner end of the spring 5 a and is engaged with each shifter 5.

Here, the inner end of the spring 5a on the side of the thrust washer 5b that is locked to the shifter 5 moves as the shifter 5 moves, and when it is in direct contact with the thrust washer 5b, Friction is generated with the washer 5b, and the spring 5a and the thrust washer 5b are easily worn by seizure due to the frictional heat. Therefore, in the embodiment shown in FIG. 4, each side clutch shaft 21 is provided with a self-lubricating oilless collar 5c, which is attached to the thrust washer 5b, and the inner end of the spring 5a and the thrust end. It is interposed between the washer 5b.

A left side brake 7L is formed between the cylindrical outer (left) side end of the left shifter 5L and the left side of the transmission case 20, and the cylindrical outer (right) side end of the right shifter 5R A right side brake 7R is formed between the right side of the transmission case 20 (the left and

right side brakes

7L and 7R are collectively referred to as “side brake 7”). Each side brake 7 includes

friction plates

7a and 7b and a pressing plate 7c. The friction plate 7 a is engaged with the cylindrical outer end portion of each shifter 5 so as not to be relatively rotatable, and the friction plate 7 b is engaged with the left and right side portions of the mission case 20 so as not to be relatively rotatable. The pressing plate 7 c is fixed to each shifter 5.

In the state where each shifter 5 is in the maximum sliding position on the inner side and each side clutch 6 is connected, the pressing plate 7c is separated from the

friction plates

7a and 7b, and the

friction plates

7a and 7b are also separated from each other. This state is a non-operating state (non-braking state) of the side brake 7. As the shifter 5 slides laterally outwardly against the spring 5a along the side clutch shaft 21 (the side clutch 6 is in a disconnected state), the pressing plate 7c that moves integrally with the shifter 5 is a friction plate. The

friction plates

7a and 7b are brought into pressure contact with each other by the pressing plate 7c. This state is the operating state (braking state) of the side brake 7. As the shifter 5 slides outward after the

friction plates

7a and 7b begin to come into pressure contact with each other, the friction pressure between the

friction plates

7a and 7b increases, and the shifter 5 (that is, the side gear in a state away from the distribution gear 22). The braking force of the side brake 7 added to 23) increases.

Further, as shown in FIG. 4, a bolt 19 for detecting the oil amount is provided in the hole 20a of the transmission case 20 of the transmission 1. A distance L1 from the axis 21c of the side clutch shaft 21 to the root of the friction plate 7a is longer than a distance L2 from the axis 21c to the center of the hole 20a. That is, the position of the hole 20 a is closer to the shaft center 21 c than the

friction plates

7 a and 7 b of the side brakes 7 along the radial direction of the side clutch shaft 21. When the bolt 19 for detecting the oil amount is attached at such a position, the operator can appropriately detect the oil amount necessary for sufficient lubrication between the

friction plates

7a and 7b. As a result, it is possible to prevent the side clutch 6 and the side brake 7 from being seized due to the lack of lubricating oil in the inclined arrangement of the mission case 20.

In the mission case 20, a pair of left and right

rotating shafts

30L and 30R (collectively referred to as “rotating shaft 30”) extending in the front-rear direction are pivotally supported in a penetrating manner. Outside the mission case 20, a vehicle steering actuator set 2 for operating the

shifters

5L and 5R is provided. The vehicle steering actuator set 2 includes a pair of left and

right steering actuators

34L and 34R (collectively “steering actuators 34”) that are hydraulic cylinders, and extends from each steering actuator 34. The piston rod 36 is connected to the outer end of each rotating shaft 30.

On the other hand, an engaging member (clamp or the like) 30 a is extended from each rotating shaft 30 inside the mission case 20 and is engaged with each shifter 5. Due to the rotation of the rotation shaft 30 around the axis, the engaging member 30 a rotates about the axis of the rotation shaft 30, so that the shifter 5 slides in the left-right direction along the side clutch shaft 21. Move.

A left large-diameter gear 25L is fixed to the right end of the left intermediate shaft 24L, and the left large-diameter gear 25L is always meshed with the left side gear 23L regardless of the sliding of the left shifter 5L. Further, the left small diameter gear 25L fixed to the left intermediate shaft 24L meshes with the left large diameter gear 27L fixed to the left axle 4L. Thus, the distribution gear 22, the left side gear 23L, the left large diameter gear 25L, the left small diameter gear 26L, and the left large diameter gear 27L constitute the left drive train 3L that transmits power from the distribution gear 21 to the left axle 4L. .

On the other hand, a right large-diameter gear 25R is fixed to the left end of the right intermediate shaft 24R, and the right large-diameter gear 25R is always meshed with the right side gear 23R regardless of the sliding of the right shifter 5R. . Further, the right small diameter gear 25R fixed to the right intermediate shaft 24R and the right large diameter gear 27R fixed to the right axle 4R are engaged with each other. Thus, the right drive train 3R for transmitting power from the distribution gear 21 to the right axle 4R is constituted by the distribution gear 22, the right side gear 23R, the right large diameter gear 25R, the right small diameter gear 26R, and the right large diameter gear 27R. . Hereinafter, the left and right large diameter gears 25L and 25R, the left and right small diameter gears 26L and 26R, and the left and right large diameter gears 27L and 27R are collectively referred to as “large diameter gear 25”, “small diameter gear 26”, and “large diameter gear 27”, respectively. .

As shown in FIGS. 2 and 5, in each housing 120, a portion for housing the small-diameter gear 26 (that is, the outer portion of each intermediate shaft 24) and the large-diameter gear 27 that are the final reduction gear train in each drive train 3. The left and right outer ends are open, and side covers 121 are joined to the outer ends of the housings 120 so as to cover the openings, and the side covers 121 are fastened to the housings 120 with bolts 121a.

The outer end of each intermediate shaft 24 is pivotally supported by each side cover 121 via a bearing 24a, while the portion of each intermediate shaft 24 between the large-diameter gear 25 and the small-diameter gear 26 supports the bearing 24b. Via the housing 120. Note that the inner end of each intermediate shaft 24 is splined into the central boss hole of each large-diameter gear 25. The outer end of each large-diameter gear 27 is pivotally supported on each side cover 121 via a bearing 27a, and the inner end of each large-diameter gear 27 is pivotally supported on each housing 120 via a bearing 27b. Yes.

The axle 4 is accommodated in and supported by the axle case 122. The outer end portion of the axle 4 protrudes from the outer end of the axle case 122. When the axle 4 is applied as, for example, a drive spline shaft of a combine crawler travel device, a drive sprocket 4 a is fixed to an outer end portion of the axle 4 protruding from the axle case 122. The inner end of the axle case 122 is a flange 122a, and the inner end of the axle 4 protrudes from the flange 122a. The outer end of the portion of each side cover 121 that supports the bearing 27 a is open, and the large-diameter gear 27 that pivotally supports the inner end of the axle 4 by the housing 120 and the side cover 122 through this opening. Insert a spline into the center boss hole. The flange 122a of the axle case 122 is joined to the outer end of the side cover 121 so as to cover the opening of the side cover 121, and the flange 122a is fastened to the side cover 121 with a bolt 122b. Is fixed to the side cover 121.

By loosening the bolt 122b and separating the flange 122a from the side cover 121, the inner end of the axle 4 is pulled out from the central boss hole of the large-diameter gear 27, and the axle 4 remains housed in the axle case 122. Thus, it can be easily removed from the mission case 20. On the other hand, with the flange 122a being fastened to the side cover 121, the bolt 121a is loosened to separate the side cover 121 from the housing 120, whereby the inner end portion of the large-diameter gear 27 is pulled out from the bearing 27b. The inner end of the shaft 24 is pulled out from the bearing 24b and the large-diameter gear 25, and the axle 4, the axle case 122, the side cover 121, the central shaft 24, the large-diameter gear 27, and the

bearings

24a and 27a are integrated into a housing. 120 can be removed.

Thus, the axle 4 can be easily detached from the transmission case 20 or removed from the transmission case 20 while the intermediate shaft 24 and the large-diameter gear 27 are supported. Maintenance, replacement, and the like of the shaft 4, the large diameter gear 27, and the bearings that support them can be easily performed. Therefore, the current intermediate shaft 24 can be replaced with another intermediate shaft 24 formed with a small diameter gear 26 having a number of teeth different from the number of teeth of the small diameter gear 26, and the number of teeth different from the current large diameter gear 27. Replacement with another large-diameter gear 27 having a number can be easily performed, and the reduction ratio of the drive train 3 can be appropriately changed by changing these combinations to other ones.

Next, the relationship between the position of the shifter 5 in the transmission 1 and the power transmission state will be described. First, FIG. 1 shows a straight traveling state of the vehicle (the left and

right axles

4L and 4R rotate at the same speed), the left and

right side clutches

6L and 6R are engaged, and the left and

right side brakes

7L and 7R are engaged. The left and right side gears 23 </ b> L and 23 </ b> R are rotatable integrally with the distribution gear 22. Therefore, in principle, the rotational force of the distribution gear 22 is transmitted to the left and

right axles

4L and 4R.

The state of the transmission 1 when the vehicle turns will be described. Here, it is assumed that an auxiliary clutch 8 described later is disengaged. When the vehicle is to turn left from the straight traveling state shown in FIG. 1, the left shifter 5L is slid outward, that is, leftward while the right shifter 5R is held at the position where the right side clutch 6R is engaged. As a result, the left side clutch 6L is disengaged and the vehicle slowly turns to the left.

Further, the pressing plate 7c fixed to the left shifter 5L presses the

friction plates

7a and 7b of the left side brake 7L, the left axle 4L is braked, and the turning radius of the vehicle is further reduced. Eventually, when the left shifter 5L that slides to the left reaches its maximum sliding position, a left brake turn is realized by completely braking the left axle 4L inside the turn.

When turning right, the right side clutch 6R is disengaged by sliding the right shifter 5R outward, that is, on the right side while holding the left shifter 5L at the position where the left side clutch 6L is engaged. The right side brake 7R is applied, and for details of the state, refer to the explanation at the time of the left turn described above, and illustration is also omitted.

The auxiliary clutch 8 in the transmission 1 will be described in detail with reference to FIGS. An auxiliary clutch 8 is provided between the left large-diameter gear 25L at the right end of the left intermediate shaft 24L and the right large-diameter gear 25R at the left end of the right intermediate shaft 24R. In this embodiment, the auxiliary clutch 8 includes a friction plate 8a engaged with the left large diameter gear 25L so as not to rotate relative to the left large diameter gear 25L, and a friction plate 8b engaged with the right large diameter gear 25R so as not to rotate relative thereto. A friction plate clutch is used, and the pressing force between the

friction plates

8a and 8b is adjustable from the outside of the mission case 20, thereby making the joining force variable. By connecting (inserting) the auxiliary clutch 8, power (torque) is transmitted between the left and right large-diameter gears 25L and 25R, that is, between the left and right drive trains 3L and 3R. The amount of torque transmitted between the left and right drive trains 3L and 3R is adjusted by adjusting the joining force of the auxiliary clutch 8.

The auxiliary clutch 8 is further provided with a pressing member (not shown) that is slidable in the axial direction (left-right direction) of the intermediate shaft 24. The

friction plates

8a and 8b are pressed against each other (with the auxiliary clutch 8 inserted), and the pressure contact degree (that is, the joining force of the auxiliary clutch 8) is increased. Thereafter, the pressure contact force of the

friction plates

8a and 8b is reduced, and the

friction plates

8a and 8b are separated (the auxiliary clutch 8 is disengaged).

In the mission case 20, an auxiliary clutch shifter 9 is provided. The auxiliary clutch shifter 9 has a fork shaft 9a and a fork 9b. The horizontally extending fork shaft 9a is supported in the mission case 20 so as to be slidable in the left-right axial direction. One end of the fork 9b is fixed to the fork shaft 9a. The other end of the fork 9b is engaged with the pressing member of the auxiliary clutch 8. Thus, by sliding the fork shaft 9a toward the clutch engagement side, the pressure contact degree between the

friction plates

8a and 8b, that is, the joining force of the auxiliary clutch 8 increases, and the fork shaft 9a slides toward the clutch disengagement side. Thus, the pressing force between the

friction plates

8a and 8b is reduced, and the auxiliary clutch 8 is separated (disengaged). The fork shaft 9a is biased toward the clutch separating side by a spring 9e.

In the mission case 20, a rotating shaft 17 is pivotally supported so as to penetrate inside and outside. An arm 16 is fixed to the outer end of the rotation shaft 17 outside the mission case 20. On the other hand, a half-shaped cam surface 17 a is formed at the inner end of the rotation shaft 17 inside the mission case 20. The one end of the fork 9b is formed as a cam receiving surface 9d that receives the cam surface 17a. Thus, the arm 16 and the rotation shaft 17 constitute the operation mechanism 15 for operating the auxiliary clutch shifter 9.

As shown in FIG. 1, when the cam surface 17a is parallel to the cam receiving surface 9d and the cam surface 17a and the cam receiving surface 9d are in close contact with each other, the fork shaft 9a is maximally slid on the clutch separating side. The auxiliary clutch 8 is disengaged as described above. Then, the fork shaft 9a is slid toward the clutch engagement side by rotating the rotating shaft 16 about its axis and making the cam surface 16a oblique with respect to the cam receiving surface 9d (see FIG. 30 and the like described later). The auxiliary clutch 9 is joined via the fork 9b with a joining force corresponding to the sliding amount.

Therefore, for example, when the left side clutch 6L that is inside the turn is disengaged in order to turn the vehicle to the left as described above, the right large diameter gear 25R changes to the left large diameter gear 25L, that is, the right drive train 3R moves to the left. Torque corresponding to the set joint force is transmitted to the drive train 3L via the auxiliary clutch 8, and a slight drive force is applied to the left axle 4L on the inside of the turn. As a result, even when the left axle 4L on the inside of the turn stops due to unexpected travel resistance during turning, the left and

right axles

4L and 4R can obtain a gentle turn as expected. Can do.

Next, the operation flow of the side clutch 6 and the side brake 7 based on the operation of the steering lever 11 will be described. As shown in FIG. 10 and the like, the steering lever 11 has, as its basic structure, a boss portion 11a at its base end mounted on a pivot 51 in the front-rear horizontal direction, and the axis of the pivot 51 is centered. It is configured to be capable of tilting up to a maximum angle Tmax from the straight position where the tilt angle T is 0 to the left and right sides. Note that the left tilt angle T from the straight position (tilt angle T = 0) is the left tilt angle LT, and the right tilt angle T from the straight position is the right tilt angle RT. By controlling the steering actuator 34 by the controller 10 as described later, the left shifter 5L is moved to the left (outward) as the steering lever 11 is tilted to the left from the straight traveling position to increase the left tilt angle LT. The right shifter 5R slides to the right (outward) as the steering lever 11 is tilted to the right from the straight position to increase the right tilt angle RT.

Until the tilt angle T of the steering lever 11 on each of the left and right sides from the straight position reaches T1, the side clutch 6 on the inner side of the turn remains engaged, that is, the both

side clutches

6L and 6R remain engaged, Is retained. When the tilt angle T reaches T1, the side clutch 6 inside the turn is disengaged. While the tilt angle T is increased from T1 to T2, the side clutch 6 on the inner side of the turn is disengaged, but the side brake 7 on the inner side of the turn is not yet operated, and the axle 4 on the inner side of the turn can rotate with inertial force. It is a state.

When the tilt angle T reaches T2, the

friction plates

7a and 7b of the side brake 7 inside the turn start to come into pressure contact. That is, the side brake 7 inside the turn starts to work. As the tilt angle T increases from T2 toward the maximum angle Tmax, the pressure contact degree of the

friction plates

7a and 7b of the side brake 7 inside the turn increases, that is, the braking force increases. When the tilt angle T reaches the maximum angle Tmax, the

friction plates

7a and 7b of the side brake 7 inside the turn are completely in pressure contact, and the axle 4 inside the turn is reliably braked.

Next, the structure of the vehicle steering actuator set 2 will be described with reference to FIGS. 1, 2, 6 to 8. The vehicle steering actuator set 2 includes an oil passage block 38, an electromagnetic direction control valve 32, a relief valve 33 having a variable relief pressure, and a pair of left and right steering actuators (hydraulic cylinders) 34L and 34R. Is. Although only shown in FIG. 1, a pair of

check valves

39L and 39R (collectively “check valves 39”) not shown in FIGS. 2 and 6 to 8 are also incorporated in the oil passage block 38. .

The oil passage block 38 is formed with a pair of parallel left and right cylinder holes. The piston 35, the piston rod 36 extending from the piston 35, and the piston rod 36 are wound around each cylinder hole. Is incorporated into the initial position to constitute a pair of left and right steering actuators (hydraulic cylinders) 34L and 34R. Both piston rods 36 are extended from an oil passage block 38, and their front ends are individually connected to the outer ends of the left and right

rotating shafts

30L and 30R as described above.

One side of the piston 35 opposite to the piston rod 36 of the cylinder hole constituting each steering actuator 34 is a hydraulic oil chamber 34a, and a relief is provided in the middle of the piston 35 in the axial direction. A port 34b is provided. The oil passage block 38 is provided with a pump port 38 a that receives the oil discharged from the hydraulic pump 31 shown in FIG. 1, and also discharges oil from the oil passage block 38 to the outside of the oil passage block 38. The drain port 38d is provided.

The oil from the hydraulic pump 31 that has flowed into the oil passage block 38 from the inlet port 38a passes through the directional control valve 32, which is an electromagnetic valve, to the hydraulic oil chamber 34a of the left steering actuator 34L and the right steering actuator 34R. It is configured to be sent to either the hydraulic oil chamber 34a or the drain port 38d. Further, the oil from the relief ports 34b of the left and

right steering actuators

34L and 34R joins via separate check valves 39 and is sent to the drain port 38d.

The pair of left and

right steering actuators

34L and 34R is controlled by the electromagnetic directional control valve 32 based on a command signal from the controller 10, so that the oil for the hydraulic oil chamber 34a of the

steering actuators

34L and 34R is controlled. Is controlled, and the extension amount of the piston rod 36 is thereby controlled. Thus, the steering actuators 34 (34L and 34R) are electronically controlled actuators in the sense that they are controlled based on the solenoid control of the direction control valve 32.

Hereinafter, for each of the steering actuators 34, the state where the corresponding shifter 5 is set to the maximum sliding position on the inner side and the side clutch 6 is engaged is referred to as the non-operating state of the steering actuator 34. A state where the shifter 5 is set to slide slightly outward from the maximum sliding position is defined as an operating state of the steering actuator 34.

As shown in FIG. 1, the direction control valve 32 is a three-position switching type direction control valve. Based on a command signal from the controller 10, the left turn position L is obtained by exciting the solenoid 32a and demagnetizing the solenoid 32b. Further, the position of the solenoid 32b is controlled to the right turning position R by the excitation of the solenoid 32b and the demagnetization of the solenoid 32a, and to the neutral position N by the demagnetization of the

solenoids

32a and 32b.

When the directional control valve 32 is in the left turn position L, the hydraulic oil chamber 34a of the left turn actuator 34L is communicated with the pump port 38a, and the left turn actuator 34L is put into an operating state and the right turn actuator 34L is used. The hydraulic oil chamber 34a of the actuator 34R is communicated with the tank port 38d, and the right-turn actuator 34R is deactivated. When the vehicle is in the right turning position R, the hydraulic oil chamber 34a of the right turning actuator 34R is communicated with the pump port 38a to bring the right turning actuator 34R into an operating state and the left turning actuator 34L. The hydraulic oil chamber 34a is communicated with the tank port 38d, and the left-turn actuator 34L is deactivated. When in the neutral position N, the pump port 38a and the hydraulic oil chambers 34a of the left and right turning

actuators

34L and 34R are communicated with the tank port 38d, and the left and right turning

actuators

34L and 34R are deactivated. .

As shown in FIG. 6, the direction control valve 32 is incorporated in an oil passage block 38, and a solenoid set 32 c of the direction control valve 32 is externally attached to the oil passage block 38. Both

solenoids

32a and 32b shown in the hydraulic circuit diagram of FIG. 1 are incorporated in the solenoid set 32c. The solenoid set 32c is connected to the controller 10 by a harness 32d so as to receive command signals 32La and 32Ra from the controller 10. The solenoid 32a is excited by receiving the command signal 32Ls, and the solenoid 32b is excited by receiving the command signal 32Rs (see FIG. 1).

On the other hand, as shown in FIG. 10, a fan-shaped arm 52 is extended from the base end boss 11a of the steering lever 11, and a recess is provided in a part of the arc-shaped edge of the fan-shaped arm 52. 52a. A pair of valve switches 53 are disposed in the vicinity of the fan-shaped arm 52, and the pusher 53 a is urged toward the fan-shaped arm 52 to rotate the fan-shaped arm 52 (that is, the steering lever 11). Accordingly, the detent groove 52a advances and retreats. When the steering lever 11 is in the straight drive position (tilt angle T = 0), the pushers 53a of both valve switches 53 are fitted into the detent grooves 52a, whereby both valve switches 53 are switched off. The controller 10 sets the direction control valve 32 to the neutral position N when the valve switch 53 is OFF.

When the steering lever 11 is turned to the left or right from the straight position, the pusher 53a of one valve switch 53 comes out of the detent groove 52a and is pushed back by being pushed by the arc edge of the sector arm 52. The valve switch 53 is switched on. As a result, a command signal is issued from the controller 10 so that one of the

solenoids

32a and 32b is excited, the directional control valve 32 is switched to the left turning position L or the right turning position R, and is used for left / right steering. Oil from the hydraulic pump 31 is supplied to one of the hydraulic oil chambers 34a of the

actuators

34L and 34R.

On the other hand, for example, as in an embodiment shown in FIG.

As shown in FIGS. 1 and 6 to 8, the relief valve 33 adjusts the degree of compression of the spring 43 by adjusting the position of the spring receiver 41, thereby adjusting the relief pressure defined by the degree of compression. It is a variable relief valve. By adjusting the relief pressure, the extension amount of the piston rod 36 of the hydraulic actuator 34 in the activated state is adjusted, that is, the sliding amount to the outside of the shifter 5 inside the turning is set, and according to the sliding amount The braking force of the side brake 7 (pressure contact degree of the

friction plates

7a and 7b) is determined.

The structure of the relief valve 33 will be described in detail. As shown in FIGS. 7 and 8, the relief valve 33 is vertically incorporated in the oil passage block 38. The relief valve 33 is fitted into the port member 40 fixed to the oil passage block 38, the spring receiver 41 engaged with the lower portion of the port member 40 so as to be slidable up and down, and slidably fitted into the port member 40. The piston 42 is disposed in the spring receiver 41, and its upper end presses against the piston 42 and its lower end includes a spring 43 that presses against the inner surface of the bottom end of the spring receiver 41.

A vertical suction port 33 a is formed at the upper end of the port member 40, and a discharge port 33 b in the horizontal radial direction is formed in the upper and lower middle part of the port member 40. The suction port 33a communicates with the relief port 34b of the

steering actuators

34L and 34R shown in FIG. 6, and the discharge port 33b is connected to the drain via an oil passage 38b formed in the oil passage block 38. It communicates with the port 38d. Although not shown in FIGS. 6 to 8, the oil passages interposed between the relief ports 34b and the suction ports 33a of the

steering actuators

34L and 34R are shown in FIG. As described above, the

check valves

39L and 39R for preventing the back flow toward the relief port 38d are provided separately.

When the piston 42 slides upward, the piston 42 closes the suction port 33a and the relief valve 33 closes. That is, even if the hydraulic oil chamber 34a is in communication with the relief port 34b due to the sliding of the piston 35 of one of the steering actuators 34, the oil released from the relief port 34b to the relief valve 33 is retained. Since the drain port 38d is not drained, the stroke pressure with respect to the piston 35 is maintained in the hydraulic pressure in the hydraulic oil chamber 34a.

On the other hand, when the piston 42 slides downward, the suction port 33a communicates with the discharge port 33b, and the relief valve 33 opens. That is, if the hydraulic oil chamber 34a is in communication with the relief port 34b by sliding of the piston 35 of one of the steering actuators 34, the oil released from the relief port 34b to the relief valve 33 is released. The drain port 38d is drained. Therefore, the hydraulic pressure in the hydraulic oil chamber 34a is reduced to a state where the piston 35 cannot be stroked any further.

A spring 43 interposed between the piston 42 and the inner surface of the bottom end of the spring receiver 41 is a compression spring, and urges the piston 42 upward. The degree of compression of the spring 43 is adjusted by adjusting the vertical position of the spring receiver 41 that can slide up and down with respect to the port member 40, thereby adjusting the relief pressure of the relief valve 33.

Furthermore, when a certain distance is provided between the spring receiver 41 and the base end of the spring 43 (referred to as “predetermined position”), when the spring receiver 41 receives no force from the outside, the spring 43 is kept at a natural length, This state corresponds to the upright position of the steering lever 11 that is kept in the state in which the side clutch 6 inside the turning is kept, as will be described in detail later.

As a means for moving the spring receiver 41 up and down, a cam plate 44 is disposed below the relief valve 33 in the oil passage block 38 as shown in FIGS. Here, as shown in FIG. 7, the outer surface of the bottom end portion of the spring receiver 44 protrudes downward in a circular arc shape in a normal (rear) view, and the upper end portion of the cam plate 44 conforms to the shape. Is formed with an arcuate recess 44a in a normal (rear) view. The left and right side portions of the concave portion 44a of the cam plate 44 serve as cams, and the spring receiver 41 rises when the bottom end of the spring receiver 41 rides on the cam.

A cam pivot member 45 having an axial center in the front-rear direction is inserted into the oil passage block 38, and an inner end portion thereof is fitted into a bush 45a as shown in FIG. It is freely supported. In the oil passage block 38, the cam plate 44 is fixed to the cam pivot member 45. An outer end portion of the cam pivot member 45 is disposed outside the oil passage block 38, and a cam operation arm 46 is fixed to the outer end portion.

6 and 8, an oil passage 38c parallel to the oil passage 38b is formed below the oil passage 38b in the oil passage block 38, and both

oil passages

38b and 38c are formed. Is connected to the drain port 38d.

7, 8, and 10, the cam operation arm 46 is connected to the sector arm 52 of the steering lever 11 through the link mechanism 50. The link mechanism 50 includes a link rod 47 on the fan-shaped arm 52 side, a link rod 49 on the cam operation arm 46 side, and a link arm 48 that connects the link rod 47 and the link rod 49. One end 47 a of the link rod 47 is pivoted to the sector arm 52, and the other end 47 b of the link rod 47 is pivoted to one end of the link arm 48. One end 49 a of the link rod 49 is pivotally connected to the other end of the link arm 48, and the other end 49 b of the link rod 49 is pivotally connected to the tip of the cam operation arm 46. The link arm 48 is pivotally supported by a pivot shaft 48a at a portion between both ends pivotally connected to the

link rods

47 and 49.

As the steering lever 11 rotates, the link rod 47 is pushed and pulled, whereby the link arm 48 rotates about the pivot shaft 48a, thereby pushing and pulling the link rod 49, and the cam operating arm. 46 is rotated. In FIG. 8, the operation position S of the cam operation arm 46 corresponds to the straight position (tilt angle T = 0) of the steering lever 11. The cam operation arm 46 can be rotated upward and downward from the rectilinear position S, and the upper position Lm corresponds to a state in which the left tilt angle LT of the steering lever 11 is set to the maximum angle Tmax. On the other hand, a position Rm below the straight traveling position S corresponds to a state where the right tilt angle RT of the steering lever 11 is set to the maximum angle Tmax.

In the relief valve 33 linked to the steering lever 11 as described above, when the tilt angle T of the steering lever 11 tilted to the right or left from the straight traveling position is T1, the position of the spring receiver 41 is The predetermined position, which is the limit position of the range in which the spring 43 is kept at a natural length, is obtained. On the other hand, in the steering actuator 34 in the activated state, the sliding position of the piston 35 (the extension amount of the piston rod 36) when the hydraulic oil chamber 34a starts to communicate with the relief port 34b determines that the clutch pawl 6b is connected to the distribution gear 22. It corresponds to the sliding position of the shifter 5 when it is removed from the clutch pawl 6a, that is, when the side clutch 6 is disengaged.

Therefore, when the steering lever 11 is tilted from the straight traveling position to the angle T1, when the side clutch 6 is disengaged, the suction port of the relief valve 33 from the relief port 34b of the turning actuator 34 in the activated state (turning inner side). The oil in the hydraulic oil chamber 34a is relieved to 33a. Here, although the spring receiver 41 moves upward from the predetermined position, the natural length of the spring 43 is maintained and the urging force (that is, the relief pressure) of the spring 43 is substantially zero, so that the suction port 33a is connected to the relief port 34b. As soon as the oil flows, the piston 42 is pushed down by the inflow pressure of the oil, and the suction port 33a and the discharge port 33b are communicated to open the relief valve 33. Therefore, the piston 35 stops the stroke, and the shifter 5 is kept in the sliding position when the side clutch 6 is disengaged (the side brake 7 is not yet applied).

After the relief port 34b communicates with the hydraulic oil chamber 34a, the piston is moved based on the movement of the spring receiver 41 based on the arbitrary setting of the tilt angle T of the steering lever 11 in the range from the angle T1 to the maximum angle Tmax. The degree of compression of the spring 43 corresponding to the urging force against 42, that is, the relief pressure of the relief valve 33 is set. Accordingly, the piston 35 of the steering actuator 34 in the operating state (inside of turning) is slid on the shifter 5 by being pushed until the hydraulic pressure in the hydraulic oil chamber 34a reaches the relief pressure set in this way, When the hydraulic pressure becomes the relief pressure and the relief valve 33 is opened, the sliding of the piston 35 and the shifter 5 stops. If the tilt angle T of the steering lever 11 at that time is equal to or greater than T2, the

brake plates

7a and 7b of the side brake 7 on the inside of the turn are pressed against each other with a pressure contact degree corresponding to the tilt angle T, A braking force corresponding to the degree of pressure contact acts on the axle 4 inside the turn.

When the left tilt angle LT of the steering lever 11 reaches the maximum angle Tmax, the position of the cam operation arm 46 becomes the “Lm” position shown in FIG. 4, and the push-up amount of the spring receiver 41 by the cam plate 44 is maximized. The urging force (compression degree) 43, that is, the relief pressure of the relief valve 33 becomes maximum, the left shifter 5L reaches the maximum outward sliding position, and the braking force of the left side brake 7L becomes maximum.

Here, a description will be given of an embodiment in which a breather 160 is configured in a portion where the vehicle steering actuator set 2 is attached to the mission case 20 shown in FIGS. FIG. 9 shows the left-right direction and the up-down direction of the transmission 1.

As shown in FIG. 3, a mounting rib 130 for attaching the oil passage block 38 of the vehicle steering actuator set 2 is formed in a front bulging shape on the front surface of the left and right housings 120 </ b> L and 120 </ b> R constituting the mission case 20. ing. A screw hole 134 is formed in the mount rib 130. The oil passage block 38 is fastened to the transmission case 20 by a bolt 38f screwed into each screw hole 134.

The mount rib 130 includes a first partition wall 130a and a second partition wall 130b. A region surrounded by the mounting rib 130 is partitioned into a first chamber 131, a second chamber 132, and a third chamber 133 by the first partition wall 130a and the second partition wall 130b. A communication hole 161 that communicates the inside of the mission case 20 and the first chamber 131 is formed in the front portion of the mission case 20. Furthermore, an air inlet 20i is formed inside the mission case 20 (see FIG. 2). Air is introduced into the first chamber 131 through the communication port 161 and the air introduction port 20i.

The first partition wall 130a is formed with a communication groove 162 that allows the first chamber 131 and the second chamber 132 to communicate with each other. A communication groove 163 that connects the second chamber 132 and the third chamber 133 is formed in the second partition wall 130b. Further, a slit-like breather groove 164 and a communication port 165 are formed in a portion of the mount rib 130 surrounding the third chamber 133. The breather groove 164 communicates the third chamber 133 and the outside of the mission case 20. Instead of the breather groove 164, a communication port may be provided on the side surface of the mount rib 130 as necessary. The communication port 165 is a small hole that communicates the third chamber 133 with the outside of the mission case 20. A breather pipe 166 facing upward is attached to the communication port 165. In FIG. 9, both the breather groove 164 and the breather pipe 166 are illustrated, but the breather 160 may have at least one of them.

Next, in order to avoid the so-called “bounce” of the shifter 5, some embodiments relating to a configuration for imparting resistance to the movement of the shifter 5 in the clutch disengaged state will be described. The “flip” of the shifter 5 means that when the side clutch 6 shifts from the disconnected state to the connected state, the clutch pawl 6b of the shifter 5 does not synchronize well with the clutch pawl 6a of the distribution gear 22, and the shifter 5 No. 5 clutch pawl 6b is “bounced” by the clutch pawl 6a of the rotating distribution gear 22. This “flipping” of the shifter 5 causes problems such as wear of the

clutch claws

6a and 6b and seizure of the spring 5a.

As a structure for imparting resistance to the movement of the shifter 5, there are a structure for imparting resistance to rotation of the steering lever 11 and a structure for imparting resistance to sliding of the shifter 5 with respect to the side clutch shaft 21. First, a resistance mechanism 170 shown in FIG. 11 will be described as a first embodiment relating to a structure for imparting resistance to the movement of the steering lever 11. The resistance mechanism 170 includes a linear fluid damper. Instead, a rotary fluid damper may be provided. The resistance mechanism 170 includes a cylinder 172, a pivot 173, an arm 174, and a piston rod 175. The cylinder 172 is formed by joining the case 172a and the case 172b, and is disposed in the vehicle by being fixed to the frame or dashboard of the vehicle. Oil or gas is sealed inside the cylinder 172.

An arm 174 is fixed to the tip of the piston rod 175, and the arm 174 is pivotally connected to the steering lever 11 via a pivot 173. When the steering lever 11 tilts to the left, the piston rod 175 moves to the left in the figure, and when the steering lever 11 tilts to the right, the piston rod 175 moves to the right in the figure. To do. In the cylinder 172,

oil seals

176a and 176b are respectively attached to the walls of the

cases

172a and 172b through which the piston rod 175 passes.

A pressure receiving chamber 171 is formed inside the cylinder 172. The pressure receiving chamber 171 is filled with fluid. The pressure receiving chamber 171 includes a side clutch region Rn, a right side brake region Rfa, and a left side brake region Rfb. Depending on the shape of the inner peripheral wall of the cylinder 172, the position of the inner peripheral wall that forms the boundary between these regions differs from region to region. Specifically, the diameter of the hole 172d that forms the right side brake region Rfa and the hole 172e that forms the left side brake region Rfb in the inner peripheral wall of the cylinder 172 is larger than the diameter of the hole 172c that forms the side clutch region Rn. It is large and close to the outer diameter of the piston portion 175c.

The piston portion 175c of the piston rod 175 is a portion protruding in a flange shape at the middle portion of the piston rod 175. An orifice hole 175d is formed in the piston portion 175c. The orifice hole 175d penetrates from the right pressing surface 175e of the piston portion 175c to the left pressing surface 175f. An oil seal 176c is attached to the outer peripheral wall surface 175h of the piston portion 175c. The piston portion 175 c moves together with the piston rod 175 as the steering lever 11 is tilted.

A step 172f and a step 172h are formed on the inner peripheral wall of the cylinder 172. The inside of the cylinder 172 is partitioned into a right side brake region Rfa and a side clutch region Rn with the step 172f as a boundary. The inside of the cylinder 172 is partitioned into a side clutch region Rn and a left side brake region Rfb with the step 172h as a boundary.

The fluid in the pressure receiving chamber 171 needs to pass through the orifice hole 175d when the piston portion 175c moves in the right side brake region Rfa and when the piston portion 175c moves in the left side brake region Rfb. Therefore, when the right pressing surface 175e of the piston portion 175c enters the right side brake region Rfa due to the rightward movement of the piston portion 175c in the side clutch region Rn, the operation resistance applied to the steering lever 11 increases. On the other hand, when the outer peripheral wall surface 175h of the piston portion 175c passes through the step 172f due to the leftward movement of the piston portion 175c in the right side brake region Rfa, the operation resistance applied to the steering lever 11 decreases. The operating resistance applied to the steering lever 11 is similarly increased or decreased by the piston portion 175c moving between the side clutch region Rn and the left side brake region Rfb.

The time when the right pressing surface 175e starts to enter from the side clutch region Rn to the right side brake region Rfa coincides with the starting point of disconnection of the right side clutch 6R. The time when the right pressing surface 175e starts to enter the right side brake region Rfa from the side clutch region Rn is the time when the position of the right pressing surface 175e matches the position of the step 172f along the direction in which the piston portion 175c moves. It is. The time when the left pressing surface 175f starts to enter the left side brake region Rfb from the side clutch region Rn coincides with the starting point of disconnection of the left side clutch 6L. The time point when the left pressing surface 175f starts to enter the left side brake region Rfb from the side clutch region Rn is the time point when the position of the left pressing surface 175f matches the position of the step 172h along the direction in which the piston portion 175c moves. It is.

The right pressing surface 175e of the piston portion 175c in the right side brake region Rfa is in a state where the outer side (right side) sliding amount of the right shifter 5R reaches the maximum value and the right side brake 7R exhibits the maximum braking force. By the time, it does not come into contact with the one end surface 172i of the inner peripheral wall of the cylinder 172. In addition, the left pressing surface 175f of the piston portion 175c in the left side brake region Rfb reaches the maximum value of the outer side (left side) sliding amount of the left side brake 7L, and the left side brake 7L exhibits the maximum braking force. Until reaching the other end surface 172j of the inner peripheral wall of the cylinder 172.

On the other hand, when the piston portion 175c moves from the right side brake region Rfa toward the side clutch region Rn, the time when the position of the right pressing surface 175e matches the position of the step 172f along the direction in which the piston portion 175c moves. By the time, the operating resistance is applied to the steering lever 11. Since the rotation of the steering lever 11 is suppressed by this operation resistance, the transition from the disconnected state to the connected state of the right side clutch 6R is suppressed. Thereby, “playing” of the right shifter 5R is suppressed. When the piston portion 175c moves from the right side brake region Rfa toward the side clutch region Rn, the operation resistance applied to the steering lever 11 is eliminated after the outer peripheral wall surface 175h of the piston portion 175c passes through the step 172f. Is done.

Further, when the piston portion 175c moves from the left side brake region Rfb toward the side clutch region Rn, until the position of the left pressing surface 175f matches the position of the step 172h along the direction in which the piston portion 175c moves. Therefore, an operating resistance is applied to the steering lever 11. Since the rotation of the steering lever 11 is suppressed by this operation resistance, the transition from the disconnected state to the connected state of the left side clutch 6L is suppressed. Thereby, “playing” of the left shifter 5L is suppressed. Then, when the piston portion 175c moves from the left side brake region Rfb toward the side clutch region Rn, after the outer peripheral wall surface 175h of the piston portion 75c passes through the step 172h, the operation resistance applied to the steering lever 11 is eliminated. Is done.

In this way, the resistance mechanism 170 switches from the state in which the side brake 7 exhibits the maximum braking force to the switching state between the disconnected state and the connected state of the side clutch 6R (position where the tilt angle T of the steering lever 11 is T1). During the period until the shifter 5 returns, the side clutch 6 is connected by applying the operating resistance R to the steering lever 11 (strictly speaking, the operating resistance R increases to a predetermined value Rh). In this direction, the sliding speed of the shifter 5 is slowed so that the clutch pawl 6b of the shifter 5R meshes with the clutch pawl 6a of the distribution gear 22 without causing "playing". Once the clutch pawl 6b is engaged with the clutch pawl 6b (the side clutch 6 is connected), no steering resistance is applied until the steering lever 11 is returned to the straight position, and conversely, the steering lever The operating resistance R is not applied until the motor 11 is tilted from the straight position (T = 0) to the tilting angle T1 (strictly speaking, the operating resistance R becomes the minimum value R0), and therefore the steering lever 11 in this tilting range is used. The quick reaction of the side clutch 6 due to the tilting of is ensured.

FIG. 12 is a graph showing the relationship between the tilt angle T of the steering lever 11 and the operating resistance R by the resistance mechanism 170 applied to the steering lever 11.

Next, a friction (resistance) mechanism 180 shown in FIGS. 13A and 13B as a second embodiment relating to a structure for imparting resistance to the movement of the steering lever 11 will be described. A friction mechanism 180 as an example of a resistance mechanism of the steering lever 11 includes an arm 181, a pressing member 182, a stopper 183, a support rod 184, a pivot 185, a boss 186, and a tension spring 187.

A boss 186 formed in the middle of the support rod 184 is provided around the pivot shaft 185, and the support rod 84 is pivotally supported by the pivot shaft 185. The support rod 184 can rotate around the central axis 185 c of the pivot 185. A pressing member 182 is provided at one end of the support rod 184, and one end of a tension spring 187 is attached to the other end. The other end of the tension spring 187 is fixed to a vehicle frame or the like.

The arm 181 is attached to the boss 11 a so as to be rotatable according to the operation of the steering lever 11. The arm 181 is located on the opposite side of the steering lever 11 with the boss 11a interposed therebetween. In the arm 181 having a fan shape, the center part of the edge of the arc shape is recessed more than the parts on both sides. This central portion is referred to as a non-friction region 181a, and the portions on both sides thereof are referred to as

friction regions

181b and 181c. Although not shown, the steering lever 11 in FIGS. 13A and 13B is also provided with left and right valve switches 53L and 53R as provided in the steering lever 11 in FIG. And a mechanism for switching between ON and OFF.

The tension coil spring 187 pulls the support rod 184 so that the pressing member 182 faces the arm 181. As a result, an elastic force is applied to the support rod 184 to rotate the support rod 184 about the pivot 185. In other words, the support rod 184 is applied with an elastic force that moves the pressing member 182 upward.

The stopper 183 is fixed to the vehicle frame or the like. In a state where the tilting angle T of the steering lever 11 is less than the angle T1, the pressing member 182 is positioned below the non-friction region 181a and does not contact the arm 181 when the support rod 184 contacts the stopper 183. .

The pressing member 182 contacts the arm 181 when the side brake 7 is activated according to the tilt of the steering lever 11, and the contact with the arm 181 is canceled when the braking force is released.

When the steering lever 11 is tilted, when the tilt angle T reaches the angle T1, the contact of the pressing member 182 with the

friction regions

181b and 181c of the arm 181 is started, so that the support rod 184 and the stopper 183 contact each other. Contact is resolved. When the steering lever 11 tilts to the right, the arm 181 contacts the pressing member 182 in the friction region 181b. When the steering lever 11 tilts to the left, the arm 181 contacts the pressing member 182 in the friction region 181c. When the arm 181 comes into contact with the pressing member 182 in the

friction regions

181b and 181c, friction is generated between the arc-shaped edge of the arm 181 and the pressing member 182, so that the operation of suppressing the tilt of the steering lever 11 is suppressed. Resistance is applied to the steering lever 11.

After the tilt angle T of the steering lever 11 tilted to the right from the straight traveling position has passed T1, until the tilt angle T reaches the maximum right tilt angle Tmax, that is, outward (rightward) of the right shifter 5R. The pressing member 182 contacts the edge of the arc-shaped arm 181 in the friction region 181b until the sliding amount reaches the maximum value and the right side brake 7R exhibits the maximum braking force. 13 continues to be applied to the arm 181. On the other hand, after the tilt angle T of the steering lever 11 tilted to the left from the straight traveling position has passed T1, until the tilt angle T reaches the maximum left tilt angle Tmax, that is, outside the left shifter 5L (left The pushing member 182 contacts the edge of the arc-shaped arm 181 in the friction region 181c until the sliding amount reaches the maximum value and the left side brake 7L reaches the maximum braking force. (Operation resistance Rh shown in FIG. 13) is continuously applied to the arm 181.

From the state where the arm 181 is in contact with the pressing member 182 in the friction region 181b or the state where the arm 181 is in contact with the pressing member 182 in the friction region 181c, the steering lever 11 is moved to the left or right. In the case of tilting, an operation resistance (Rh) is applied to the steering lever 11 until the arm 181 is separated from the pressing member 182. Then, after the arm 181 is opposed to the pressing member 182 in the non-friction region 181a and is separated from the pressing member 182, the steering lever is operated while the arm 181 rotates counterclockwise to the rectilinear position. 11, the operation resistance by the pressing member 182 is not applied (the operation resistance is the minimum value R0).

As described above, the friction mechanism 180 disengages the side clutch 6 while the shifter 5 returns from the state in which the side brake 7 exhibits the maximum braking force to the start point of transition from the disconnected state of the side clutch 6 to the connected state. The operation resistance that suppresses the transition from the state to the connected state is continuously applied to the steering lever 11 and “play” of the shifter 5L is suppressed.

Next, a resistance mechanism 188 shown in FIG. 14 will be described as an example of a structure for imparting resistance to the sliding of the shifter 5 with respect to the side clutch shaft 21.

The resistance mechanism 188 is provided with a friction portion 21f on the outer peripheral surface of the side clutch shaft 21 on which the shifter 5 slides. The friction part 21f has a friction coefficient larger than the friction coefficient of the outer peripheral surface of the side clutch shaft 21 where the friction part 21f is not provided. As a means for providing the friction portion 21f, it is conceivable to coat the outer peripheral surface of the side clutch shaft 21 with a friction material. As a method of coating the friction material, a method of attaching a sheet-like friction material, A method of spraying or applying a friction material can be considered. Alternatively, instead of providing a friction material different from the side clutch shaft 21, a method of surface processing the outer peripheral surface of the side clutch shaft 21 itself is also conceivable. 14 shows the left side clutch shaft 21 provided with the friction portion 21f, the friction portion 21f is also provided on the right side clutch shaft 21 not shown in FIG.

As shown in FIG. 12, during the movement of the shifter 5 on the side clutch shaft 21, when the bush 5d of the inner peripheral portion of the shifter 5 comes into contact with the friction portion 21f, a certain sliding resistance Rh is applied to the shifter 5, When the bush 5d does not contact the friction part 21f (when it contacts the part other than the friction part 21f on the outer peripheral surface of the side clutch shaft 21), the minimum value R0 of the sliding resistance is applied. The position of the shifter 5 where the sliding resistance changes between R0 and Rh corresponds to the position where the side clutch 6 moves between the connected state and the disconnected state, and the tilt angle T of the steering lever 11 is T1. Corresponds to the position.

While the shifter 5 moves outward (to the left if the shifter 5 is the left shifter 5L) to disengage the side clutch 6, the sliding resistance that was initially the minimum value R0 increases to a constant sliding resistance Rh. . When the shifter 5 moves outward, the contact point between the outer end 5d1 of the bush 5d and the friction part 21f is coincident with the starting point of the side clutch 6 being disengaged. That is, the sliding resistance is the minimum value R0 while the side clutch 6 is engaged while the shifter 5 is sliding (while the

clutch claws

6a and 6b are engaged), and the clutch pawl 6b is separated from the clutch pawl 6b. As soon as the shifter 5 is detached, a sliding resistance Rh is applied to the shifter 5, and thereafter, a sliding resistance of a constant value Rh is applied during the outward sliding of the shifter 5. Even when the braking force applied to the side clutch shaft 21 by the site brake 7 reaches the end position of the outward sliding of the shifter 5, the inner end 5d2 of the bush 5d is outside the friction portion 21f. Since the bush 5d is in contact with the friction portion 21f, the shifter 5 is still subjected to the sliding resistance Rh.

When the shifter 5 moves inward (rightward in FIG. 14), the sliding resistance Rh is applied to the shifter 5 until the contact between the bush 5d and the friction portion 21f is eliminated. The sliding resistance Rh suppresses the transition of the side clutch 6 from the disconnected state to the connected state. Thereby, the “play” of the shifter 5 is suppressed. When the clutch pawl 6b of the shifter 5 starts to mesh with the clutch pawl 6a of the distribution gear 22, the outer end 5d1 of the bush 5d passes through the friction portion 21f, and thereafter the sliding resistance applied to the shifter 5 is eliminated ( The sliding resistance is the minimum value R0).

As can be understood from the above description, the tilt angle T of the steering lever 11 and the steering as shown in FIG. A relationship with the value of the operating resistance applied to the lever 11 appears.

Next, a resistance mechanism 189 shown in FIGS. 15 (A) and 15 (B) as another embodiment relating to a structure for imparting resistance to the movement of the steering lever 11 will be described.

The resistance mechanism 189 includes a detent mechanism 190. The detent mechanism 190 includes a ball 193, a plate portion 191 with which the ball 193 is slidably contacted, a case 192 for holding the ball 193 facing the ball 193, and a spring 194 that is a compression coil spring. The plate portion 191 is provided with a right recess 191a and a left recess 191b. The right recess 191a and the left recess 191b are portions that are recessed from the surface 191c of the plate portion 191. The plate portion 191 is fixed to a frame or dashboard of a vehicle on which the transmission 1 is mounted.

The case 192 is fixed to the steering lever 11. Case 192 includes a hook portion 192a and a cap portion 192b. The spring 194 is received at the bottom of the cap portion 192b. The ball 193 is pushed by the spring 194 toward the outside of the cap portion 192b. In the case 192, the hook portion 192 a is fixed to the steering lever 11. When the steering lever 11 is tilted, the case 192 moves together. The plate portion 191 is formed in an arch shape so as to coincide with the movement locus of the case 192 at that time.

When the steering lever 11 is in the rectilinear position, the ball 193 is positioned between the right concave portion 191a and the left concave portion 191b and does not fit in either, and is in contact with the surface 191c of the plate portion 191. Further, even when the tilt angle T increases to reach the angle T1, the ball 193 is in contact with the surface 191c of the plate portion 191. When the right tilt angle RT of the steering lever 11 reaches the angle T2, the ball 193 is fitted into the right recess 191a.

When the left tilt angle LT of the steering lever 11 reaches the angle T2, the ball 193 is fitted into the left recess 191b. When the steering lever 11 further tilts when the tilt angle T is equal to or greater than the angle T2, the ball 193 rides on the surface 191c of the plate portion 191 from the right recess 191a or the left recess 191b and then moves again on the surface 191c. To do. Only when the ball 193 fitted in the right concave portion 191a or the left concave portion 191b rides on the surface 191c of the plate portion 191, the manipulation resistance R of the value Rh is applied to the steering lever 11 operated by the operator.

In the state where the left and

right side brakes

7L and 7R exhibit the maximum braking force, the ball 193 is in contact with the surface 191c. When the ball 193 slides on the surface 191c, the operation resistance R of the minimum value R0 is applied to the steering lever 11.

Thus, when the shifter 5 returns from the state in which the side brake 7 exhibits the maximum braking force to the transition start point of the side clutch 6 from the disconnected state to the connected state, the resistance mechanism 189 immediately before the transition start point. An operation resistance that suppresses the transition of the side clutch 6 from the disconnected state to the connected state for a moment is applied to the steering lever 11 to prevent the “shift” of the shifter 5.

Next, the joining pressure setting operation means and the joining pressure increasing operation means of the auxiliary clutch 8 will be described. As shown in FIG. 1, a vehicle equipped with a transmission 1 is provided with an auxiliary clutch engagement pressure setting lever (hereinafter simply referred to as “lever”) 12 as an operation tool for setting the engagement pressure of the auxiliary clutch 8. . The arm 16 is rotated to a position corresponding to the operation position of the lever 12, thereby controlling the position of the auxiliary clutch shifter 9, and the pressure contact degree between the

friction plates

8 a and 8 b in the auxiliary clutch 8 is determined. It is assumed that it corresponds to the value set by lever 12.

Further, as shown in FIG. 1, an auxiliary clutch engagement pressure increasing pedal (hereinafter referred to as “auxiliary clutch engagement pressure increase pedal”) can be increased in a vehicle equipped with the transmission 1 from the value set by the lever 12. A simply “pedal”) 13 is provided. The pedal 13 is mechanically linked to an arm 16 for controlling the auxiliary clutch shifter 9 using a link mechanism 14. As an aspect of use of the pedal 13, for example, when the vehicle gets muddy during turning, the auxiliary clutch 8 joined with the joining pressure set by the lever 12 is used from the drive train 3 outside the turning, The driving force is transmitted to the driving train 3 on the inner side of the turn with the side clutch 6 disengaged, but with the set joining pressure of the auxiliary clutch 8, there is not enough power to be transmitted to remove the muddyness. When it feels, the pedal 13 is urgently depressed, and the joining force of the auxiliary clutch 8 is increased according to the depression amount.

In the embodiment shown in FIG. 18, a stopper 68 that demarcates the non-depressed position of the pedal 13 is movable up and down. It is controlled by a control type actuator 67. The related structure of the lever 12, the pedal 13, and the arm 16 in the embodiment of FIG. 7 will be described in detail.

The pedal 13 has a boss 13a formed at the base end mounted on a pivot 70 having a horizontal axis, and is pivotable up and down around the pivot 70. An arm 13b extends downward from the boss 13a, and when the pedal 13 is depressed and lowered, the arm 13b rotates forward. An outer wire receiver 63 is installed immediately after the arm 13 b, and a spring 64 is interposed between the tip (lower end) of the arm 13 b and the outer wire receiver 63. The spring 64 urges the arm 13b rearward, thereby urging the pedal 13 upward (non-depressed position). The depression of the pedal 13 is performed against the spring 64. When the depression of the pedal 13 is released, the pedal 13 is rotated upward by the urging force of the spring 64 and returns to the non-depressed position.

The outer wire receiver 65 is also installed in the vicinity of the arm 16, and both ends of the outer wire 62 are fixed to the

outer wires

63 and 65. An inner wire 61 is inserted into the outer wire 62, and one end portion 61 a of the inner wire 61 extending from one end portion of the outer wire 62 fixed to the outer wire receiver 63 is pivotally connected to the arm 13 b and is fixed to the outer wire receiver 65. The other end 61b of the inner wire 61 extending from the other end of 62 is pivoted to the tip of the arm 13b. Thus, the inner wire 61, the outer wire 62, and the

outer wire receivers

63, 65 constitute the link mechanism 14 that links the pedal 13 and the arm 16, and when the pedal 13 is depressed, the arm 13b resists the spring 64. It rotates and pulls the inner wire 61, thereby rotating the arm 16 in the increasing direction of the joining pressure of the auxiliary clutch 8.

The lever 12 is pivotable back and forth around the pivot 71 by mounting the boss 12a at the base end thereof to the pivot 71 in the left-right direction. The lever 12 is inserted through a lever guide groove 19 in the front-rear direction provided on the console of the vehicle, for example, and is rotatable in a range from the front end to the rear end of the lever guide groove 19. Thus, in the longitudinal rotation range of the lever 12 defined by the lever guide groove 19, an operation for setting the operation position of the lever 12 as the front end position thereof to the minimum value (for example, 0) of the auxiliary clutch 8 is set. The operation position for setting the operation pressure of the lever 12 as the rear end position to the maximum value within the setting range of the lever 12 is set as the operation position of the lever 12 as the rear end position. "Maximum bonding pressure setting position Cmax". In other words, by turning the lever 12 rearward, the set joining pressure of the auxiliary clutch 8 is increased.

In the lever guide groove 19, notches (saw teeth) for detent are formed for each operation position of the lever 12 corresponding to each set value of the joining pressure of the auxiliary clutch 8. When setting the joining pressure of the auxiliary clutch 8, the operator puts his hand on the lever 12 and rotates it along the guide groove 19 and arranges it at the operation position corresponding to the target joining pressure. Here, by locking the lever 12 in the notch formed at the operation position, the lever 12 is fixed at the operation position even when the lever 12 is released. Thus, as long as the lever 12 is fixed at the operating position and the pedal 13 is set to the non-depressed position, the joining pressure of the auxiliary clutch 8 is held at a set value corresponding to the operating position of the lever 12. . When the joining pressure of the auxiliary clutch 8 is changed, the lever 12 is removed from the notch at the original operation position, the lever 12 is rotated to another operation position, and the notch corresponding to the other operation position is set. The lever 12 is locked.

In the vicinity of the lever 12, a position detection sensor 66 for detecting the rotation position (operation position) of the lever 12 is disposed. The controller 10 sends a command signal to the actuator 67 based on the detection signal of the position detection sensor 66, and the actuator 67 positions the stopper 68 in response to the command signal. The position where the pedal 13 urged upward by the spring 64 presses against the stopper 68 is the non-depressed position of the pedal 13 in a state where the joint pressure of the auxiliary clutch 8 is set by the lever 12 at that time. The higher the joining pressure of the auxiliary clutch 8 set by the lever 12, the lower the position of the stopper 68, and the lower the position of the pedal 13 at the non-depressed position defined by the stopper 68 at that position. The joint pressure of the auxiliary clutch 8 is also increased through the arm 16 and the shifter 9.

Thus, when the lever 12 is operated, the joint pressure of the auxiliary clutch 8 in the state where the pedal 13 is in the non-depressed position is set. When the operator feels that the joint pressure is not sufficient, By depressing the pedal 13 from the non-depressed position, the joint pressure of the auxiliary clutch 8 increases from a value set by the lever 12 to a value corresponding to the depressing amount of the pedal 13.

When the steering lever 11 for turning the vehicle is operated, the pressure contact degree of the

braking plates

7a and 7b of the side brake 7 inside the turning is the tilt angle of the steering lever 11 in the range of T2 to Tmax as described above. It depends on the setting of T. At this time, the side clutch 6 on the inner side of the turn is disconnected, but if the joint pressure of the auxiliary clutch 8 is set by the lever 12, the side brake 7 drives the drive train 3 on the outer side of the turn via the auxiliary clutch 8. The drive train 3 inside the turning which is driven by receiving a part of the force is braked. Here, when the pedal 13 is depressed, the driving force is further transmitted to the driving train 3 inside the turning, the resistance against the side brake 7 is increased, and the

friction plates

7a and 7b of the side brake 7 and the friction plates of the auxiliary clutch 8 are increased. Image sticking is likely to occur in both 8a and 8b. On the other hand, a situation where the pedal 13 is depressed is considered to be a case where the rotational speed of the axle 4 inside the turn falls below the assumed speed, that is, rather than applying the side brake 7 further in this state, This is a case where it is desired to increase the rotational speed of the axle 4 on the inside of the turn until the joining pressure of the auxiliary clutch 8 is increased to increase the amount of power transmitted from the drive train 3 on the outside of the turn to the drive train 3 on the inside of the turn.

Therefore, in order to prevent the depression of the pedal 13 and the operation of the side brake 7 from being performed at the same time (that is, not to perform the other when one of them is being performed) A check mechanism 18 as shown in FIGS. 16 to 18 is provided. The structure of the check mechanism 18 will be described with reference to the embodiments shown in FIGS. The check mechanism 18 includes a pusher 54 provided on the fan-shaped arm 52, a regulating member 55, a pivot member 56, and the like. A regulating member 55 is disposed in the vicinity of the steering lever 11, and this regulating member 55 is linked to the pedal 13 via the link mechanism 60, so that the regulating member 55 is interlocked with the depression of the pedal 13. Is switched to a state in which the tilting of the steering lever 11 is restricted.

As shown in FIG. 16, a pivot member 56 is installed in the vicinity of the steering lever 11. The pivot member 56 is formed by interposing a vertical pivot 56a between a pair of upper and lower horizontal plate-

like brackets

56b and 56b fixed to the wall or the like of the cab of the vehicle. The restricting member 55 has a vertical boss 55c. The restriction member 55 has a pair of upper and lower horizontal plate-

like restriction portions

55a and 55b extending in parallel to one side from the boss 55c. Further, the restricting member 55 has a horizontal plate-like arm 55d extending from the boss 55c to the other side of the boss 55c, that is, on the opposite side of the restricting

portions

55a and 55b via the pivot 56a. Yes.

On the other hand, when the one end portion 47a of the link rod 47 of the link mechanism 50 of the fan-shaped arm 52 formed integrally with the steering lever 11 is pivoted, the steering lever 11 is in the straight advance position. The pusher 54 is formed as an extension part 52b that extends horizontally, and a pusher 54 that can be pushed against the

restriction part

55a or 55b of the restriction member 55 is provided at the tip part. The positions of the extension part 52b and the pusher 54 when the steering lever 11 is arranged at the straight-ahead position are just intermediate positions between the upper and lower restricting parts 55a in the vertical direction.

Further, in this embodiment, when the steering lever 11 is rotated to the right for turning the vehicle to the right, the extending portion 52b and the pusher 54 are rotated upward to turn the vehicle to the left. When the steering lever 11 is rotated to the left, the extending portion 52b and the pressing element 54 are configured to rotate downward. Accordingly, the upper restricting portion 55a is for restricting the rotation of the steering lever 11 from the straight traveling position to the right, and the lower restricting portion 55b is the steering lever from the straight traveling position to the left. However, the relationship between the left and right turning directions of the steering lever 11 and the upper and lower restricting

portions

55a and 55b may be reversed.

Conversely, when the pressing element 54 is above the upper restricting portion 55a or below the lower restricting portion 55b, that is, out of the range between the upper and lower restricting

portions

55a and 55b. In this case, the pusher 54 and the extending portion 52b of the fan-shaped arm 52 restrict the rotation of the upper and lower restricting

portions

55a and 55b toward the fan-shaped arm 52. As a result, the depression of the pedal 13 linked to the regulating member 55 is regulated as will be described later.

An outer wire receiver 59 is installed in the vicinity of the arm 55 d of the regulating member 55, and one end portion of the outer wire 58 is fixed to the outer wire receiver 59, while the other end portion of the outer wire 58 is fixed to the outer wire receiver 63. ing. An inner wire 57 is inserted into the outer wire 58. The inner wire 57 extends from one end of the outer wire 58 fixed to the outer wire receiver 59, and the one end 57a is pivotally connected to the tip of the arm 55d. On the other hand, the inner wire 57 extends from the other end portion of the outer wire 58 fixed to the outer wire receiver 63, and the other end portion 57 b is pivotally connected to the arm 13 b of the pedal 13. In this manner, the inner wire 57, the outer wire 58, and the

outer wire receivers

59 and 63 constitute the link mechanism 60 that links the restricting member 55 and the pedal 13.

In the embodiment shown in FIG. 20, in the outer wire receiver 63, the outer wire 58 is disposed above the outer wire 62. Of the

inner wires

57 and 61 extending from the outer wire receiver 63 to the arm 13 b, the inner wire 57 is the Although arranged above, this vertical relationship may be reversed. Further, the

end portions

57b and 61b of both the

inner wires

57 and 61 are pivoted to one side of the arm 13b, but these may be pivoted to the other side of the arm 13b, or the end portions of the inner wire 57 57b may be connected to one side of the arm 13b, and the end 61b of the inner wire 61 may be connected to the other side of the arm 13b.

With the structure of the link mechanism 60 as described above, as the pedal 13 is depressed, the inner wire 57 is pulled by the arm 13b, and the arm 55d of the restricting member 55 rotates horizontally around the vertical pivot 56a, and is integrated therewith. The upper and lower restricting

portions

55a and 55b rotate horizontally.

Here, FIGS. 16 to 18 show the restriction release position X and the restriction position Y of the upper and

lower restriction portions

55a and 55b. When the upper / lower restricting

portions

55a and 55b are in the restriction release position X, the pusher 54 is moved upward or downward with the steering lever 11 while the fan-shaped arm 52 rotates. In other words, since the rotation of the sector arm 52 is not restricted, the steering lever 11 can be rotated until the tilt angle T reaches the maximum angle Tmax. Therefore, the side brake 7 on the inside of the turn can be operated in the braking state.

When the upper / lower restricting

portions

55a and 55b are in the restricting position Y, when the steering lever 11 is tilted from the straight advance position to an angle, the pusher 54 is pushed against the upper restricting portion 55a or the lower restricting portion 55b. The steering lever 11 cannot be tilted before the angle. That is, the turning of the steering lever 11 and the fan-shaped arm 52 is restricted. The tilt angle T of the steering lever 11 when the pressing element 54 presses against the upper restricting portion 55a or the lower restricting portion 55b is an angle in the range of T1 to T2. Thereby, although the side clutch 6 inside the turning is cut off, the side brake 7 inside the turning is not applied.

In addition, while the upper / lower restricting

portions

55a and 55b are in the restriction release position X, the tilt angle T of the steering lever 11 reaches the range of T2 to Tmax and the side brake 7 on the inside of the turn is applied. When the pedal 13 is to be depressed to increase the joint pressure of the auxiliary clutch 8, the restriction member 55 is rotated by the depression of the pedal 13, but the upper restriction part 55a or the lower restriction part 55b (for example, the control member 55). When the direction lever 11 is tilted to the right, the upper restricting portion 55 a) cannot reach the restricting position Y by being blocked by the extending portion 52 b and the pusher 54 of the fan-shaped arm 52. In this way, when the rotation of the restricting member 55 is prevented, it is transmitted via the link mechanism 60 and the downward rotation of the pedal 13 is also prevented. As a result, when the side brake 7 on the inside of the turn is applied, an increase in the joining pressure of the auxiliary clutch 8 due to the depression of the pedal 13 is restricted.

In FIG. 18, when the pedal 13 is pressed against the stopper 68 and is in the non-depressed position, the upper / lower restricting

portions

55a and 55b are arranged at the restriction release position X and the pedal 13 is depressed to the depressed position D. Further, a mode in which the upper and lower restricting

portions

55a and 55b are arranged at the restricting position Y is illustrated. Here, as described above, the non-depressed position of the pedal 13 is defined by the positioning of the stopper 68 based on the operation of the lever 12, but the joining pressure of the auxiliary clutch 8 is set within the range set by the lever 12. The side brake 7 needs to be applied while the vehicle is on. Therefore, the depression position D corresponds to the maximum joint pressure of the auxiliary clutch 8 in the range set by the lever 12 (joint pressure obtained by placing the lever 12 at the maximum joint pressure setting position Cmax). The position is set in a range from the position (the non-depressed position of the pedal 13 defined by the stopper 68 positioned at the lowest position of the vertical movable range) to the maximum depressed position. In each of the embodiments shown in FIGS. 19 to 28 described later, the depression position D of the pedal 13 set in this way is adopted.

When the pedal 13 is depressed to the depression position D while the vehicle is traveling straight or when the side clutch 6 inside the turn is turned off but the side side brake 7 is not applied when the vehicle is turning, the joint pressure of the auxiliary clutch 8 is It is increased beyond the maximum value in the setting range of the lever 12. Even if the steering lever 11 is further tilted from this state and the side brake 7 is to be applied, the upper and lower restricting

portions

55a and 55b of the restricting member 55 are disposed at the restricting position Y, and the steering lever 11 The tilt angle T cannot reach a range exceeding T2, and the side brake 7 is not applied.

On the other hand, in the state where the pedal 13 is in the non-depressed position, the upper / lower restricting

portions

55a and 55b are in the restriction releasing position X, and the steering lever 11 is tilted for turning the vehicle, and the tilt angle T is set to T2. When reaching the range of ~ Tmax, the side brake 7 on the inner side of the turning acts (becomes a braking state). From this state, even if the pedal 13 is depressed to the depression position D in order to increase the joint pressure of the auxiliary clutch 8, the pusher 54 and the extending portion 52 b of the fan-shaped arm 52 prevent the restriction member 55 from rotating. Thus, the upper / lower restricting

portions

55a and 55b cannot be rotated to the restricting position Y, and therefore the pedal 13 cannot be depressed to the depressed position D.

With the configuration as described above, when the value of the joining pressure of the auxiliary clutch 8 is within the range that can be set by the lever 12, the steering lever 11 can be tilted to the range from the tilt angle T2 to the maximum angle Tmax. Thus, the side brake 7 inside the turn can be applied. When the pedal 13 is depressed to increase the joining pressure of the auxiliary clutch 8 beyond a range that can be set by the lever 12, the restricting member 55 rotates the fan-shaped arm 52 and the pusher 54 in the check mechanism 18. By blocking the movement, the tilt angle T of the steering lever 11 is restricted until T2 is reached, and the side brake 7 does not work. On the other hand, when the steering lever 11 is tilted in the range from the tilt angle T2 to the maximum angle Tmax and the side brake 7 on the inside of the turn is applied, the fan-shaped arm 52 and the pusher 54 are regulated in the check mechanism 18. By blocking the rotation of the member 55, the pedal 13 is restricted until reaching the stepping position D, and the stepping-on pressure of the auxiliary clutch 8 that attempts to increase beyond the range that can be set by the lever 12 is applied. It cannot be increased to the value of the bonding pressure corresponding to the position D.

As described above, in the embodiment shown in FIGS. 16 to 18, the control mechanism 18 is provided in the steering lever 11 and the control mechanism 18 is linked to the pedal 13 via the link mechanism 60. The check mechanism 18 and the link mechanism 60 simultaneously perform the tilting operation of the steering lever 11 for applying the side brake 7 and the depression operation of the pedal 13 for increasing the joining pressure of the auxiliary clutch 8 beyond the set range. It is configured to function so as to restrict one operation when trying to break.

As described above, the steering lever 11 as the steering operating means for turning the vehicle, the lever 12 as the operating means for setting the joining pressure of the auxiliary clutch 8, and the auxiliary clutch 8 shown in FIGS. The embodiment (first embodiment) related to the linkage structure of the pedal 13 for increasing the set pressure of the joint pressure of the pedal has been described. FIGS. 19 to 26 show other embodiments (second to fifth embodiments) relating to such an association structure. Hereinafter, these examples will be described. In the drawings showing the respective embodiments, the same members and parts as those described before the description of the embodiments or the members and parts having the same functions are denoted by the same reference numerals. Will be omitted in principle.

First, the second embodiment shown in FIGS. 19 and 20 will be described. In this embodiment, the structure in which the position of the stopper 68 that defines the non-depressed position of the pedal 13 is controlled by the actuator 67 based on the detection of the operation position of the lever 12 is that of the first embodiment of FIGS. Is the same.

A fan-shaped arm 72 extends from the boss 11 a of the steering lever 11, and the pusher 53 a of the valve switch 53 is fitted when the steering lever 11 is set to the straight movement position, as in the above-described fan-shaped arm 52. The detent groove 72a configured to be formed in a part of the arc edge of the sector arm 72, and the link rod of the link mechanism 50 connected to the cam operating arm 46 for relief pressure control of the relief valve 33 An end 47 a of 47 is pivotally connected to the fan-shaped arm 72.

In this embodiment, another type of check mechanism 18A as a check mechanism for restricting simultaneous operation of the steering lever 11 and the pedal 13 is provided in the steering lever 11 as follows. A restriction groove 72 b is formed in the other part of the arc edge of the sector arm 72. In the vicinity of the fan-shaped arm 72, a regulating member 74 that is rotatable around a pivot 73 that extends in the front-rear horizontal direction parallel to the pivot 51 as a pivot fulcrum of the steering lever 11 is disposed. ing. The restricting member 74 has a boss 74a mounted on the outer peripheral surface of the pivot 73, and a restricting arm 74b and a connecting arm 74c are extended from the boss 74a. A roller 75 is pivotally supported at the tip of the regulation arm 74 b, and the roller 75 is fitted into the regulation groove 72 b of the sector arm 72 by rotating the regulation arm 74 b toward the sector arm 72. .

On the other hand, a pushing member 81 disposed adjacent to the pedal 13 is pivotally supported on the pivot 70. The pushing member 81 has a boss 81 a, which is attached to the pivot 70 so as to be adjacent to the boss 13 a of the pedal 13. A pressing rod 81b extends from the boss 81a. The pushing rod 81b extends in the radial direction of the pivot 70, then bends and extends in parallel to the pivot 70, and this extended portion is disposed immediately before the arm 13b of the pedal 13. Yes. The pushing member 81 is urged by urging means (not shown) so that the pushing rod 81b is pressed against the front end of the arm 13b.

Further, a connecting arm 81 c is formed on the push member 81 so as to extend from the boss 81 a in the other radial direction of the pivot 70. An outer wire receiver 78 is disposed in the vicinity of the connecting arm 74 c of the restricting member 74, and an outer wire receiver 79 is disposed in the vicinity of the connecting arm 81 c of the pushing member 81. One end of the outer wire 77 is fixed to the outer wire receiver 78, and the other end of the outer wire 77 is fixed to the outer wire receiver 79. An inner wire 76 is inserted into the outer wire 77, and one end 76 a of the inner wire 76 extending from one end of the outer wire 77 fixed to the outer wire receiver 78 is pivotally connected to the tip of the connecting arm 74 c and fixed to the outer wire receiver 79. The other end 76b of the inner wire 76 extending from the other end of the outer wire 77 is pivotally connected to the tip of the connecting arm 81c. Thus, the inner wire 76, the outer wire 77, and the

outer wire receivers

78 and 79 constitute a link mechanism 80 that links the control member 74 on the steering lever 11 side and the pushing member 81 on the pedal 13 side.

When the pedal 13 is lowered, the arm 13b rotates forward to push the pressing rod 81b pressed against the front end of the arm 13b. As a result, the pushing member 81 rotates about the pivot 70, the connecting arm 81 c pulls the connecting arm 74 c via the inner wire 76 of the link mechanism 80, and rotates the regulating member 74 about the pivot 73. . By this rotation, the restriction arm 74 a is rotated toward the sector arm 72. When the pedal 13 is depressed to the depression position D, the roller 75 of the restriction arm 74 b that rotates toward the sector arm 72 is fitted into the restriction groove 72 b of the sector arm 72.

The restricting groove 72b has a certain width in the direction of the arc edge of the fan-shaped arm 72, and the roller 75 when fitted into the restricting groove 72b is rotated by the tilt of the steering lever 11 from the straight position. Accordingly, the relative position in the regulation groove 72b can be moved. The width of the restriction groove 72b is such that when the tilting angle T of the steering lever 11 tilted to the left or right from the straight traveling position reaches an angle in the range of T1 to T2, the roller 75 has the width of the restriction groove 72b. It is set so that the fan-shaped arm 72 cannot be rotated any more after reaching the end.

By configuring the check mechanism 18A, the link mechanism 80, and the like as described above, when the pedal 13 is depressed to the depressed position D when the vehicle is traveling straight or when the side brake 7 is not applied, the regulating member 74 rollers 75 are inserted into the restriction grooves 72b of the fan-shaped arm 72, and the rotation of the fan-shaped arm 72 is restricted. As a result, the tilt of the steering lever 11 from the rectilinear position reaches the tilt angle T2. The range is limited, and the side brake 7 inside the turn does not work.

On the other hand, in the state where the steering lever 11 is tilted until the tilt angle T exceeds T2 and the side brake 7 on the inner side of the turning is operating, the restriction groove 72b of the sector arm 72 has a roller 75 at the tip of the restriction arm 74b. Deviate from the rotation trajectory. In this state, even if the pedal 13 is depressed to the depression position D, the roller 75 is pressed against the arc edge of the sector arm 72 outside the restriction groove 72b, and the rotation of the restriction member 74 is restricted. Thus, the depression of the pedal 13 is limited in the range up to the depression position D, and the joint pressure of the auxiliary clutch 8 cannot be increased to that extent.

Next, a third embodiment shown in FIGS. 21 and 22 will be described. In this embodiment, the steering lever 11 is provided with a check mechanism 18 similar to that of the first embodiment shown in FIGS. 16 to 18, while an arm 82 separate from the lever 12 and the pedal 13 is provided. The link mechanism 14 provided and connected to the arm 16 linked to the auxiliary clutch shifter 9 is interposed between the arm 82 and the arm 16. The arm 82 is mechanically linked to the lever 12 and the pedal 13, and rotates by the operation of the lever 12 to rotate the arm 16 via the link mechanism 14 (changes the joining pressure of the auxiliary clutch 8). In addition, after the lever 12 reaches the operation position where the joint pressure of the auxiliary clutch 8 is set to the maximum value in the set range, the lever 12 is rotated by depressing the pedal 13 and is then connected via the link mechanism 14 to the arm 16. Is rotated.

A boss 82 a is formed at the base end of the arm 82. By mounting the boss 82 a on the pivot 71 in a state adjacent to the boss 12 a of the lever 12, the arm 82 is pivoted independently of the lever 12. It can be rotated in the front-rear direction around 71.

The lever 12 is formed with a pressing rod 12b extending from the boss 12a. The pushing bar 12b extends in the radial direction of the pivot 71, then bends and extends in parallel to the pivot 71, and this extending portion is disposed immediately in front of the arm 82.

The outer wire receiver 87 is disposed in the vicinity of the arm 82, and the end of the outer wire 62 of the link mechanism 14 and the end of the outer wire 58 of the link mechanism 60 are fixed to the outer wire receiver 87. An inner wire 61 of the link mechanism 14 inserted through the outer wire 62 and connected to the position control arm 16 of the auxiliary clutch shifter 9 extends from the outer wire receiver 87, and its end 61 a is pivotally connected to the arm 82. . Further, the inner wire 57 of the link mechanism 60 inserted through the outer wire 58 and connected to the arm 55 d of the restricting member 55 extends from the outer wire receiver 87, and its end 57 b is pivotally connected to the arm 82.

Furthermore, one end 83a of the inner wire 83 is pivotally connected to the arm 82, and the other end 83b of the inner wire 83 is pivotally connected to the arm 13b of the pedal 13. The inner wire 83 is inserted through the outer wire 84. One end of the outer wire 84 is fixed to the outer wire receiver 63 in the vicinity of the arm 13 b of the pedal 13. On the other hand, the other end of the outer wire 84 is fixed to an outer wire receiver 12 c formed on the lever 12. Thus, the inner wire 83, the outer wire 84, and the

outer wire receivers

12c and 63 constitute the link mechanism 85 that links the arm 82 and the pedal 13.

A spring 64 for biasing the pedal 13 upward is interposed between the arm 13b of the pedal 13 and the outer wire receiver 63. The urging force of the spring 64 is transmitted to the arm 82 via the link mechanism 85, and the arm 82 is urged to rotate forward, and is pressed against the pressing rod 12b of the lever 12 disposed immediately before. Has been.

Note that a stopper 86 is provided that delimits the upper end position in the rotation range of the pedal 13 biased upward by the spring 64. The stopper 86 used in the embodiment shown in FIGS. 21 and 22 is fixed. The pedal 13 when pressed against the stopper 86 is disposed at a position where the joining force of the auxiliary clutch 8 is set to a minimum value (for example, 0).

21 and 22, when the lever 12 is used to increase the set value of the joining pressure of the auxiliary clutch 8, the lever 12 is rotated backward. As the lever 12 rotates backward, the pressing rod 12b pushes the arm 82 backward against the biasing force of the spring 64. The rearward rotation of the lever 12 is also transmitted to the restricting member 55 via the link mechanism 60, and the upper and lower restricting

portions

55a and 55b of the restricting member 55 are rotated. Within the rotation range of the restriction member 55 based on the rotation from the position Cmin to the maximum joining pressure setting position Cmax, the

restriction portions

55a and 55b are, for example, at the restriction release position X shown in the figure, and the sector arm 52 is turned. Is not restricted so that the side brake 7 on the inside of the turn does not work.

While the lever 12 rotates, the arm 82 rotates backward together with the lever 12 to push the inner wire 83 of the link mechanism 85 rearward. However, since the outer wire receiver 12c is integrally formed with the lever 12, The inner wire 83 moves and bends together with the outer wire 84. Therefore, the inner wire 83 does not move relative to the outer wire 84, and the extension length of the inner wire 83 from the outer wire receiver 63 to the arm 13b of the pedal 13 does not change. For this reason, the pedal 13 does not move in the position pressed against the stopper 86. That is, in this embodiment, the link mechanism 14 connected to the arm 16 is connected to an arm 82 different from the pedal 13, and the pedal 13 applies the joint pressure of the auxiliary clutch 8 during operation of the lever 12. The position is held at a position where it is pressed against the stopper 86, which corresponds to the operation position set to the minimum value (eg, 0). In other words, in this embodiment, the position of pressing against the stopper 86 is always the non-depressed position of the pedal 13 regardless of the operation of the lever 12.

In a state where the lever 12 is fixed at any setting position within the range from the minimum joining pressure setting position Cmin to the maximum joining pressure setting position Cmax, the pedal 13 is depressed, and the non-depressed position that is a pushing position with the stopper 86 When the arm 13b is lowered, the arm 13b rotates integrally with the pedal 13, and the arm 13b pulls the inner wire 83 of the link mechanism 85, thereby rotating the arm 82 rearward.

Thus, the arm 82 moves rearward away from the pushing rod 12b of the lever 12 in a state of being fixed at the set position (at the notch of the guide groove 19 described above) and further rotated rearward. The rearward rotation of the arm 82 is transmitted to the arm 16 via the link mechanism 14 to operate the shifter 9 in a direction that increases the joining pressure of the auxiliary clutch 8, while Is also transmitted to rotate the upper and lower restricting

portions

55a and 55b. When the depressed pedal 13 reaches the depressed position D, the upper and lower restricting

portions

55a and 55b of the restricting member 55 reach the restricting position Y, restricting the rotation of the fan-shaped arm 52 of the steering lever 11, and turning inside The side brake 7 is not effective.

On the other hand, when the operation position of the lever 12 is changed in the range from the minimum joining pressure setting position Cmin to the maximum joining pressure setting position Cmax, the movement of the lever 12 is transmitted to the regulating member 55 via the arm 82 and the link mechanism 60. As long as the regulating member 55 rotates, as long as the pedal 13 is placed in the non-depressed position, the upper /

lower regulating portions

55a and 55b are, for example, in the state of the regulation release position X and to the regulation position Y. The rotation of the fan-shaped arm 52 and the pressing element 54 is not restricted. In this state, the tilt angle T of the steering lever 11 is reached to the range of T2 to Tmax, the side brake 7 on the inner side of the turn is applied, and then the pedal 13 is depressed to increase the joint pressure of the auxiliary clutch 9 Accordingly, the restricting member 55 also rotates. However, the upper and lower restricting

portions

55a and 55b cannot be rotated to the restricting position Y by being blocked by the extending portion 52a and the pusher 54 of the fan-shaped arm 52. . Due to the rotation restriction of the restriction member 55, the backward rotation of the arm 82 is also restricted, and the pedal 13 cannot be lowered to the depression position D via the link mechanism 85, and the pedal 13 is brought to the depression position D. The arm 16 cannot be rotated via the link mechanism 14 until the joining pressure of the auxiliary clutch 8 is increased to a corresponding value. Thus, when the side brake 7 is effective, an increase in the joint pressure of the auxiliary clutch 8 due to the depression of the pedal 13 is restricted.

When the arm 82 is rotated by rotating the lever 12, the outer wire receiver 12c that fixes the end of the outer wire 84 is moved together with the lever 12 together with the inner wire 83 in the link mechanism 85. However, when the arm 82 is rotated while the pedal 13 is depressed, the inner wire 83 moves relative to the outer wire 84, and the outer wire receiver 12 c that fixes the end of the outer wire 84 does not move along with the inner wire 83. Therefore, while the pedal 13 is depressed, the lever 12 remains in the set position (locked to the notch) at that time. Accordingly, when the depression of the pedal 13 is released, the pedal 13 is rotated upward by the urging force of the spring 64 and returned to the non-depressed position, whereby the inner wire 83 of the link mechanism 85 is pushed and the arm 82 is returned to a position where it is pressed against the pressing rod 12b of the lever 12 fixed at the set position. Further, when the arm 82 returns to the position defined by the lever 12 in the setting position, the

arms

16 and 55d also return to the position corresponding to the setting position of the lever 12 via the

link mechanisms

14 and 60.

Next, a fourth embodiment shown in FIGS. 23 and 24 will be described. Also in this embodiment, as in the third embodiment of FIGS. 21 and 22, an arm 82 separate from the lever 12 and the pedal 13 is used, and the arm 82 is connected to the arm 16 via the link mechanism 14. In addition, it is connected to the restriction member 55 of the check mechanism 18 via the link mechanism 60.

That is, in this embodiment, as shown in FIG. 24, the boss 12 a of the lever 12, the boss 82 a of the arm 82, and the boss 13 a of the pedal 13 are mounted adjacent to the horizontal pivot 70. Is disposed between the lever 12 and the pedal 13. In the lever 12, a pressing rod 12 c is extended from the boss 12 a, and a portion that is bent and extends horizontally to the left and right is disposed immediately before the arm 82. On the other hand, also in the pedal 13, a pressing rod 13c extends from the boss 13a in the radial direction of the pivot 70, and the pressing rod 13c is bent and extends in the horizontal direction toward the tip thereof. The extension part is shifted in the vertical direction with respect to the extension part in the left-right direction of the pressing rod 12c immediately before the arm 82, that is, the

pressing rods

12c and 13c rotate with respect to each other. Arranged so as not to interfere.

A spring stopper 88 is disposed in the vicinity of the arm 13b of the pedal 13, and a spring 64 is interposed between the spring stopper 88 and the arm 13b, so that the pedal 13 is brought into a position where the pedal 13 is pressed against the stopper 86. It is energizing upward. The arm 82 is biased so as to rotate forward by a biasing means (not shown) different from the spring 64, thereby pressing against the

pressing rods

12 c and 13 c arranged immediately before the arm 82. ing.

When the lever 12 is rotated backward to increase the joining pressure of the auxiliary clutch 8, the pressing rod 12c that rotates integrally with the lever 12 pushes the arm 82 backward. The backward rotation of the arm 82 is transmitted to the

arms

16 and 55d through the

link mechanisms

14 and 60. While the lever 12 and the arm 82 are integrally rotated, the pedal 13 is held in the non-depressed position where the pedal 13 is pressed against the stopper 86 by the biasing force of the spring 64. The arm 82 stays in the position and rotates backward away from the pressing bar 13c.

In a state where the lever 12 is fixed at any setting position in the range from the minimum joining pressure setting position Cmin to the maximum joining pressure setting position Cmax, the pedal 13 is depressed against the spring 64 and pressed against the stopper 86. When the pedal 13 is lowered from the non-depressed position, the pressing rod 13c rotates backward integrally with the pedal 13. Here, until the pedal 13 reaches the stepping position corresponding to the joining pressure set by the lever 12, the rearward rotation of the pressing rod 13c is the distance between the arm 82 and the arm 82 disposed rearward. When the pedal 13 reaches the depressed position, the pressing rod 13c is pressed against the arm 82.

Then, when the pedal 13 is further lowered from the stepping position corresponding to the joining pressure set by the lever 12, the pressing rod 13c pushes the arm 82 backward. At this time, the lever 12 is fixed at the set position, and the arm 82 is separated rearward from the pressing rod 12c of the lever 12 remaining at the position. When the arm 82 is rotated backward, the shifter 9 is operated in a direction to increase the joining pressure of the auxiliary clutch 8. The rotation of the sector arm 52 of the direction lever 11 is restricted so that the side brake 7 on the inner side of the turning is not effective.

On the other hand, while the pedal 13 is placed in the non-depressed position, the tilt angle T of the steering lever 11 is reached to the range of T2 to Tmax and the side brake 7 on the inside of the turn is applied, and then the auxiliary clutch 9 When the pedal 13 is depressed to increase the joint pressure, the restricting member 55 rotates as well. However, the upper and lower restricting

portions

55a and 55a are blocked by the extension portion 52a and the pusher 54 of the sector arm 52. 55b cannot reach the restriction position Y. Due to the rotation restriction of the restriction member 55, the backward rotation of the arm 82 is also restricted, and the auxiliary clutch 8 is engaged to the value corresponding to the depression position D of the pedal 13 and the depression position D of the pedal 13. The arm 16 cannot be rotated until the pressure is increased. Thus, when the side brake 7 is effective, an increase in the joint pressure of the auxiliary clutch 8 due to the depression of the pedal 13 is restricted.

Next, a fifth embodiment shown in FIGS. 25 to 28 will be described. As shown in FIG. 25, a fan-shaped arm 90 is extended from the boss 11a at the base end of the steering lever 11 mounted on the front and rear horizontal pivot 51 to the left and right sides. A detent groove 90a is formed in part, and the pressing element 53a of the valve switch 53 is fitted into the detent groove 90a when the steering lever 11 is in the linear position. As in the embodiment shown in FIG. 16 and the like, the valve switch 53 is switched off when the pressing element 53a is inserted into the detent groove 90a, so that the directional control valve 32 is set to the neutral position N. By switching off from the detent groove 90a, the directional control valve 32 is turned to the left turning position L or the right turning position R. Whether the direction control valve 32 is set to the turning position L or the right turning position R is determined by detecting whether the steering lever 11 is rotated leftward or rightward from the straight traveling position. (It may be determined based on detection of the rotation direction of the cam operation arm 46).

Further, an arm 91 extends from the boss 11 a of the steering lever 11 to the left and right sides, and a push pin 91 a protrudes from the arm 91. Furthermore, upper and

lower arms

93 and 94 are pivotally supported on the pivot 51, and the

arms

93 and 94 are extended from the pivot 51 on the other left and right sides, that is, on the same side as the arm 91. Yes. Between the upper and

lower arms

93 and 94, there are arranged a push pin 91a of the arm 91 and a fixed pin 92 which is fixed in position regardless of the rotation of the steering lever 11. A spring 95 is interposed between the tip portions of the upper and

lower arms

93 and 94. The upper and

lower arms

93 and 94 are urged toward each other by the spring 95, that is, urged in a direction in which the pressing pin 91a and the fixing pin 92 are sandwiched therebetween.

In this embodiment, the steering lever 11 is tilted to the right from the straight traveling position (increasing the right tilting angle RT), thereby turning the upper arm 93 upward and moving the steering lever 11 to the left from the straight traveling position. By tilting in the direction (increasing the left tilt angle LT), the lower arm 93 is rotated downward. This will be described in detail. The arm 91 rotates integrally with the steering lever 11, and as shown in FIG. 26, when the steering lever 11 is rotated rightward from the straight position, the push pin 91a of the arm 91 is moved upward. The arm 93 is pushed upward. During this time, the fixed pin 92 whose position is fixed is located at a position where the steering lever 11 is in the straight traveling position so that the lower arm 94 does not rotate upward following the upper arm 93. The arm 94 is kept. On the other hand, although not shown, as can be seen from FIG. 26, when the steering lever 11 is rotated leftward from the straight advance position, the push pin 91a of the arm 91 pushes down the lower arm 94 downward. During this time, the fixed pin 92 is fixed so that the upper arm 93 follows the lower arm 94 and does not rotate downward so that the steering lever 11 is in the straight position. The arm 93 is kept.

Thus, by turning the steering lever 11 from the straight position to the left or right, the distance between the tip portions of the upper and

lower arms

93 and 94 is widened, the spring 95 is extended, and the

arms

93 and 94 are moved. Energize towards each other. When the hand is released from the steering lever 11 that has been rotated right or left from the straight position, the

arm

93 or 94 that has been rotated by being pushed up or down by the push pin 91a is engaged by the fixed pin 92. It rotates toward the

arm

93 or 94 that is stopped, and the push pin 91a is pushed by the turning

arm

93 or 94, and the arm 91 is turned together with the push pin 91a. The direction lever 11 rotates. Eventually, as shown in FIG. 25, both

arms

93 and 94 return to the state of sandwiching the push pin 91a and the fixing pin 92, and the steering lever 11 also returns to the straight advance position.

In this embodiment, a wire member made of an inner wire 98 and an outer wire 99 is used as the link mechanism 50 connected to the cam operation arm 46 for controlling the relief valve 33 of the vehicle steering actuator set 2. The link mechanism 50 shown in FIG. 16 rotates the cam operation arm 46 upward by turning the steering lever 11 to the left, and rotates the cam operation arm 46 downward by rotating the steering lever 11 to the right. However, as described above, the relationship between the turning direction of the steering lever 11 and the turning direction of the cam operation arm 46 is not limited in this way. It is sufficient if the cam operation arm 46 is appropriately rotated based on the rotation of 94.

One of the

arms

93 and 94 constitutes an outer wire receiver, and the end of the outer wire 99 is fixed. The other of the

arms

93 and 94 is connected to the end of the inner wire 98. It is said. In the present embodiment, an outer wire receiver 94a for fixing the end portion of the outer wire 99 is formed (or fixed) on the lower arm 94, and the end portion 98a of the inner wire 98 extended from the outer wire receiver 94a is disposed on the upper side. The arm 93 is pivotally connected.

Further, the outer wire receiver 94a of the lower arm 94 has an end portion of the outer wire 102 inserted through the inner wire 101 connected to the pedal 13, and the inner wire 101 extends from the outer wire receiver 94a. The end 101a is fixed to one of the ends of the restricting member 96 (the lower end in this embodiment). The restriction member 96 is provided with a long hole 96a formed long in the direction between both ends of the restriction member 96 (substantially in the vertical direction in the present embodiment). A restriction pin 93a to be provided is inserted. A spring 97 is provided between the other of the ends of the restricting member 96 (the upper end in the present embodiment) and a part of the vehicle (a part where the position is fixed, for example, a part of the wall of the cab or the instrument panel). It is installed.

As described above, the steering lever 11 in the present embodiment, in which the

arms

93 and 94, the spring 95, and the like are provided as urging means for returning the steering lever 11 to the straight position, is used for increasing the joint pressure of the auxiliary clutch 8. As a check mechanism for preventing the depression of the pedal 13 and the operation of the side clutch 7 from being performed at the same time, a check mechanism 18B including a restricting member 96 and a spring 97 is provided. The restriction member 96 of the check mechanism 18B is structured to be linked to the pedal 13.

The link mechanism 100 includes an inner wire 101 and an outer wire 102. One end of the outer wire 102 is fixed to the outer wire receiver 94a of the lower arm 94, and the other end is fixed to the outer wire receiver 63 in the vicinity of the arm 13b of the pedal 13. The inner wire 101 is inserted into the outer wire 102, the end 101 a of the inner wire 101 extending upward from the outer wire receiver 94 a is locked to the lower end of the restricting member 96, and the end of the inner wire 101 extending from the outer wire receiver 63. 101b is pivotally connected to the arm 13b.

In the present embodiment, as in the first embodiment of FIGS. 16 to 18, the link mechanism 14 including the inner wire 61, the outer wire 62, and the like is interposed between the arm 13 b and the arm 16 of the pedal 13. . In relation to the lever 12, as in the first embodiment of FIGS. 16 to 18, the position of the stopper 68 that defines the non-depressed position of the pedal 13 according to the setting of the joining pressure of the auxiliary clutch 8 at the lever 12 is determined. It is possible to change. Alternatively, as in the third embodiment of FIGS. 21 and 22 and the fourth embodiment of FIGS. 23 and 24, a fixed stopper 86 is provided, which is related to the setting of the joining pressure of the auxiliary clutch 8 at the lever 12. Alternatively, it may be possible to make the non-depressed position of the pedal 13 pressed against the stopper 86 constant. In any case, the check mechanism 18B in the present embodiment is configured so that the joint pressure of the auxiliary clutch 8 obtained in the operation range of the lever 12 from the minimum joint pressure setting position Cmin to the maximum joint pressure setting position Cmax Regardless of whether or not the clutch 7 is operated, it can be obtained.

The restricting member 96 in the check mechanism 18B has an elongated hole 96a in the vertical direction, and a restricting pin 93a projecting from the upper arm 93 extends along the elongated hole 96a in the vertical direction. And is slidably inserted. Of the upper and lower ends of the restricting member 96 arranged with the long hole 96a interposed therebetween, the end 101a of the inner wire 101 is locked to the lower end, as described above, and one end of the spring 97 is engaged with the upper end. It has been stopped. The other end of the spring 97 is locked to a portion (for example, a wall of a cab) fixed in the vehicle. Thus, the restricting member 96 moves up and down according to the movement of the link mechanism 100 and the movement of the

arm

93 or 94, and the spring 97 expands and contracts according to the up and down movement of the restricting member 96. Allow vertical movement.

FIG. 25 shows a case where the steering lever 11 is disposed at the straight traveling position (tilt angle T = 0) and the pedal 13 is disposed at the non-depressed position. The upper and

lower arms

93 and 94 are in a position corresponding to the straight position of the steering lever 11, and the extension length of the inner wire 101 from the outer wire receiver 94a to the lower end of the regulating member 96 is such that the

arms

93 and 94 are in this position. , The restriction member 96 is at the uppermost position in the range of the vertical movement, the spring 97 is in the most compressed state, and the restriction pin 93a is in contact with the lower end of the long hole 96a.

25, when the steering lever 11 is tilted to the right from the straight advance position while the pedal 13 remains in the non-depressed position, as shown in FIG. 26, the restricting member 96 remains held at the aforementioned position (spring 97 remains in the most compressed state), the upper arm 93 rotates upward, and the relative position of the restricting member 96a within the elongated hole 96a moves upward. In this case, the restriction pin 93a that moves upward does not hit the upper end of the long hole 96a until the right tilt angle RT of the steering lever 11 reaches the maximum angle Tmax. It is possible to increase the pressure to the maximum value and bring the right drive train 3R and the right axle 4R to a complete braking state.

On the other hand, since the restriction pin 93a raised by the upward rotation of the upper arm 93 in this manner shortens the distance from the upper end of the long hole 96a, the downward movement of the restriction member 96 is restricted. Here, when the right tilt angle RT of the steering lever 11 is in the range up to T2, the side brake 7R is not yet applied, but the restriction that has moved upward with the upward rotation of the upper arm 93 at this time. The distance between the pin 93a and the upper end of the long hole 96a is still sufficient, and the lowering amount of the restricting member 96 is ensured to allow the lowering of the pedal 13 to the depressed position D.

However, when the right tilt angle RT of the steering lever 11 exceeds T2 and the side brake 7R is applied, the relative position of the restriction pin 93a in the long hole 96a at this time increases, and the restriction pin 93a And the distance between the upper end of the long hole 96a is short, and that distance is not enough for the lowering amount of the restricting member 96 to lower the pedal 13 to the depressed position D. In other words, when the pedal 13 is depressed, the regulating member 96 is lowered, but the lowering is blocked by the regulating pin 93a, and the pedal 13 cannot be lowered to the depressed position D, whereby the side brake 7R is effective. In this state, an increase in the joining pressure of the auxiliary clutch 8 due to the depression of the pedal 13 is suppressed.

On the other hand, as shown in FIG. 25, the distance between the restriction pin 93a in the long hole 96a and the upper end of the long hole 96a when the pedal 13 is in the non-depressed position and the steering lever 11 is in the straight position. Therefore, the lowering amount of the restricting member 96 that only lowers the pedal 13 to the depression position D is ensured, and therefore, the joint pressure of the auxiliary clutch 8 can be increased as the operator desires by depression of the pedal 13.

Here, when the pedal 13 is depressed to the depression position D while the steering lever 11 is held in the straight traveling position, the inner wire 101 is pulled downward while the position of the regulation pin 93a is maintained as shown in FIG. Thus, the regulating member 96 is lowered and the spring 97 is extended. Accordingly, the relative position of the restriction pin 93a in the long hole 96a moves upward, and the distance between the restriction pin 93a and the upper end of the long hole 96a is reduced. The distance between the restriction pin 93a and the upper end of the elongated hole 96a when the pedal 13 is in the depressed position D is compared with the upward movement amount of the restriction pin 93a accompanying the upward rotation of the upper arm 93. 11 is secured for the upward movement of the regulation pin 93a until the right tilt angle T of T11 exceeds T1 (that is, the side clutch 6R is disengaged), but the right tilt angle T of the steering lever 11 reaches T2. It is set so as to be insufficient for the upward movement of the restriction pin 93a up to the point.

Therefore, when the upper arm 93 rotates upward from the state where the pedal 13 is lowered to the depression position D until the right tilt angle RT of the steering lever 11 reaches T2, as shown in FIG. 93a is pressed against the upper end of the long hole 96a, and beyond that, the upper arm 93 cannot be rotated upward. Thus, the tilting of the steering lever 11 until the right tilt angle T of the steering lever 11 becomes equal to or greater than T2 is restricted, and the side brake 7R inside the turn is not applied while the pedal 13 is depressed to the depression position D. -ing

Although the case where the steering lever 11 is tilted to the left from the straight traveling position to rotate the lower arm 94 downward is not shown, this case will be described with reference to FIGS. When the lower arm 94 rotates downward as the steering lever 11 tilts to the left, the inner wire 101 of the link mechanism 100 is pushed downward together with the outer wire 102. As a result, the restricting member 96 moves downward, and the spring 97 extends to allow the restricting member 96 to move. At this time, since the upper arm 93 is held at the position when the steering lever 11 is set to the straight advance position, the regulation pin 93a does not move. Therefore, the distance between the restriction pin 93a and the upper end of the long hole 96a is reduced as the lower arm 94 is rotated downward.

As described above, in the link mechanism 100, when the steering lever 11 is tilted to the left, the lower arm 94 rotates, so that the outer wire 102 moves together with the inner wire 101, while the pedal 13 is depressed. In this case, the outer wire 102 is left as it is, and only the inner wire 101 moves by being pulled by the arm 13 b of the pedal 13. As described above, when the steering lever 11 is rotated to the left and the left tilt angle LT reaches T2, the distance between the restriction pin 93a and the upper end of the long hole 96a is simply to lower the pedal 13 to the depressed position D. Accordingly, the amount of lowering of the regulating member 96 due to the movement of the inner wire 101 is not sufficient, and therefore, the pedal 13 cannot be lowered to the depressed position D. Thus, when the steering lever 11 is tilted to the left and the side brake 7L is applied, an increase in the joint pressure of the auxiliary clutch 8 when the pedal 13 is depressed is suppressed.

On the other hand, when the pedal 13 is lowered to the depressed position D while the steering lever 11 is in the straight traveling position, the state shown in FIG. This distance is not sufficient for the lowering amount of the regulating member 96 accompanying the downward rotation of the lower arm 94 until the left tilt angle LT of the steering lever 11 reaches T2, and therefore the left of the steering lever 11 The tilt angle LT cannot reach T2. In this way, when the pedal 13 is depressed to increase the joint pressure of the auxiliary clutch 8, the side brake 7L does not work even if the steering lever 11 is tilted to the left.

Next, transmission 1A shown in FIGS. 29 to 32 and transmission 1B shown in FIGS. 33 and 34 will be described as examples of the transmission 1 in which the joining pressure of the auxiliary clutch 8 can be automatically adjusted. FIG. 3 is also a diagram showing the internal structure of the

transmission

1A or 1B, and is used to explain these embodiments. Further, the members and parts indicated by the same reference numerals as those used in the embodiments described so far are the same or have the same functions as the members and parts in the above-described embodiments, and the description thereof is omitted. .

Here, the technical background that enables the joint pressure of the auxiliary clutch 8 to be automatically adjusted will be described. The joint pressure of the auxiliary clutch 8 can be manually adjusted by adjusting the amount of depression of the pedal 13 by an operator, for example, as shown in FIG. However, it is difficult to always select the best joining pressure of the auxiliary clutch 8 only by the operator's judgment due to differences in conditions such as soil conditions. There is a possibility that it is not possible. Therefore, as in the following example, the turning at the desired turning radius assumed by the operation of the steering operation tool (steering lever 11) can be accurately obtained regardless of the difference in the state of the soil, etc. In addition, the operator's effort to enable such turning is unnecessary.

First, for the

transmissions

1A and 1B, the steering actuator for controlling the left shifter 5L is the steering actuator SAL, and the steering actuator for controlling the right shifter 5R is the steering actuator SAR. The steering actuator SA is used. The

transmissions

1A and 1B include an auxiliary clutch actuator AA as an actuator for automatically controlling the position of the shifter 9 for the auxiliary clutch 8. The auxiliary clutch actuator AA has an electric motor as shown in FIG. An actuator (electric actuator) 141 is used.

The transmission 1A includes an actuator control system having a hydraulic circuit structure similar to that of the steering actuator set 2 described above. ) Is the steering actuator SAL / SAR. In the transmission 1A, these are referred to as hydraulic cylinders 34 (34L and 34R) as steering actuators SA (SAL and SAR).

On the other hand, the transmission 1B includes the same steering actuators SAL / SAR as the electric actuator 141 used as the auxiliary clutch actuator AA, and the steering actuator SAL / SAR as the steering actuator SAL / SAR. The

actuators

141L and 141R will be referred to.

The transmission 1A will be described with reference to FIG. 3, FIG. 29 to FIG. As described in the description of the transmission 1 described above, the rotation shaft 17 extending in the front-rear direction is pivotally supported at the rear portion of the transmission case 20 so as to penetrate inside and outside. An auxiliary clutch electric actuator 141 serving as an auxiliary clutch actuator AA is provided on the outer end of the rotation shaft 17 outside (rearward) the transmission case 20.

29, the

hydraulic cylinders

34L and 34R as the steering actuators SAL and SAR and the electric actuator 141 as the auxiliary clutch actuator AA are controlled based on a command signal from the controller 10. Here, with respect to each steering actuator SA, the state where the corresponding shifter 5 is set to the maximum sliding position on the inner side and the side clutch 6 is joined is referred to as a non-operating state of the steering actuator SA. A state where the shifter 5 is set to slide slightly outward from the maximum sliding position on the inner side is defined as the operating state of the steering actuator SA. On the other hand, for the auxiliary clutch actuator AA, the state in which the shifter 9 is set to the maximum sliding position on the clutch separating side to separate the auxiliary clutch 8 is referred to as the non-operating state of the auxiliary clutch actuator AA. The state in which the shifter 9 is set to slide to the clutch engagement side even a little from the maximum sliding position is defined as the operating state of the auxiliary clutch actuator AA.

In addition, the vehicle includes a steering lever 11, an auxiliary clutch automatic control switch 112 (hereinafter simply referred to as “switch 112”), and an auxiliary clutch engagement force setting dial 113 ( Hereinafter, the dial 113 is simply provided), and a potentiometer 11p, a switch 112, and a dial 113 provided at the base of the steering lever 11 to detect the operation position of the steering lever 11 are connected to the controller 10. It is provided as an input means. In other words, the detection means provided in each of the potentiometer 11p, the switch 112, and the dial 113 detects the operation positions of the respective operation tools, and

detection signals

11s, 112s, and 113s indicating the operation positions are input to the controller 10. It is supposed to be.

Further, the left and

right axles

4L and 4R are provided with

rotation speed sensors

114L and 114R for detecting the respective rotation speeds, and detection signals 114Ls and 114Rs of the respective

rotation speed sensors

114L and 114R are input to the controller 10. It is supposed to be. In the controller 10, in response to the

input detection signals

11s, 112s, 113s, 114Ls, and 114Rs, command contents for the

hydraulic cylinders

34L and 34R and the auxiliary clutch electric actuator 141 are determined, and a command signal based on the determination is sent. It is something that is emitted.

As the steering lever 11 is tilted to the left from the straight traveling position to increase the tilt angle T, the potentiometer 11p outputs a signal 11s having a value corresponding to the tilt angle and direction, and the signal 11s is input to the controller 10. The The controller 10 transmits a command signal 32Ls to the direction control valve 32 to excite the solenoid 32a so as to correspond to this signal 11s, and the direction control valve 32 is set to the “L” position so that the piston rod of the steering actuator 34L. The command signal 33s is transmitted to the relief valve 33, and the relief pressure of the relief valve 33 for defining the piston rod extension amount (that is, defining the sliding position of the shifter 5L) is determined. On the other hand, as the steering lever 11 is tilted to the right from the straight traveling position to increase the tilt angle T, the signal 11s generated by the potentiometer 11p is input to the controller 10, and the controller 10 corresponds to the signal 11s. The command signal 32Rs is transmitted to the direction control valve 32 to excite the solenoid 32a, the direction control valve 32 is set to the “R” position, the piston rod of the steering actuator 34R is extended, and the command signal 33s is supplied to the relief valve 33. This is transmitted to determine the relief pressure of the relief valve 33 for defining the piston rod extension amount (that is, defining the sliding position of the shifter 5R).

In addition, as an input means to the controller 10 for transmitting the command signal 32Ls or 32Rs to the direction control valve 32, a valve switch 53 as shown in FIGS. 1, 10, 16 or the like may be provided.

The switch 112 is a switching operation means for deciding whether or not to perform automatic control of the auxiliary clutch 8 (whether or not to perform manual control), and an “ON” position for performing the automatic control, It is switched to two positions, “OFF” position, in which automatic control is not performed (joint force F of auxiliary clutch 8 is manually set).

The dial 113 is a means for setting the joining force when the joining force of the auxiliary clutch 8 is manually set, that is, when the switch 112 is set to the “OFF” position. The dial 113 can be rotated from a “0” position where the joining force F of the auxiliary clutch 8 is 0 (that is, when the auxiliary clutch 8 is disengaged) to an “Fmax” position where the joining force F is the maximum value Fmax. The joining force F of the auxiliary clutch 8 is set according to the moving position. As the position of the dial 113 is closer to the “Fmax” position, a larger bonding force F is set. Note that several setting positions are determined between the “0” position and the “Fmax” position, and the dial 113 is set to one of these setting positions, so that the joining force F is set stepwise. Alternatively, the joining force F can be changed in a stepless manner, and the dial 113 can be joined in correspondence with an arbitrary turning position of the dial 113 that can be turned steplessly from the “0” position to the “Fmax” position. The force F may be set.

The switch 112 and the dial 113 are installed on an instrument panel that displays a vehicle speed and an engine speed on a dashboard provided in front of the steering lever 11 in the vehicle, for example. It is possible. Furthermore, it is conceivable to install an auxiliary clutch engagement force meter 117 indicating the actual value (current value) of the engagement force F of the auxiliary clutch 8 as shown in FIG. 41 on such an instrument panel. The operator can visually check the current value of the engagement force F of the auxiliary clutch 8 that changes every moment by automatic control with the auxiliary clutch engagement force meter 117. In the present embodiment, a liquid crystal display device is used as the auxiliary clutch engagement force meter 117, but display means having any structure may be used. Further, in this embodiment, on the assumption that the maximum bonding force Fmax is a bonding force F of “100%”, the bar graph indicates what percentage of the maximum bonding force Fmax the actual value of the bonding force F is. However, any display method may be used as long as the operator can recognize the current joining force F of the auxiliary clutch 8.

Further, as positioning operation means for the left and

right shifters

5L and 5R, an operation means for switching automatic control / manual control of the engagement force of the auxiliary clutch 8, and an operation means for setting the engagement force of the auxiliary clutch 8 when setting the manual control, The structure is not limited to the steering lever 11, switch 112, and dial 113 described above, and any structure may be used as long as the functions required for each can be ensured. For example, as shown in FIG. 1, the switch 112 may be replaced with the lever 12 and the dial 113 may be replaced with the pedal 13.

Alternatively, as shown in FIGS. 42 and 43, a dial 113A as an operating means for setting the engagement force of the auxiliary clutch 8 at the time of manual control setting is placed in front of the upper end portion of the grip portion 11b of the steering lever 11. Is also possible. In this embodiment, the dial 113A includes a fixed portion 113a fixed to the grip portion 11b of the steering lever 11, and an annular direction around the shaft center of the steering lever 11 provided around the fixed portion 113a. The rotary portion 113b is formed with a knob portion 113c so that the operator can rotate it with a thumb snap. The fixed portion 113a is printed with a scale indicating the frequency of the joining force F of the auxiliary clutch 8 (0, 1, 2, 3, 4 in this embodiment), and the operator can turn the rotating portion via the knob portion 113c. 13b is rotated in the R direction, and the index printed on the rotating portion 113b is adjusted to one of the scales of the fixed portion, so that the frequency of the joining force F of the auxiliary clutch 8 is arbitrarily set.

As the auxiliary clutch actuator AA, as shown in FIGS. 31 and 32, the electric actuator 141 mounted on the outside (rear) of the mission case 20 has an electric motor 142 that can rotate forward and backward as its drive source. The output shaft of the electric motor 142 is a worm 144. A gear case 144 is connected to the electric motor 142, and the gear case 143 supports the outer end portion of the rotating shaft 17, and is perpendicular to the worm 144 and the rotating shaft. A counter shaft 145 extending in parallel with 17 is supported. A worm wheel 146 and a pinion 147 are fixed to the counter shaft 145, and the worm wheel 146 meshes with the worm 144. A sector gear 148 is fixed to the outer end of the rotating shaft 17 and meshes with the pinion 147.

The controller 10 rotates the electric motor 142 based on the steering lever 11, the switch 112, the dial 113, and the input signals 11s, 112s, 113s, 114Ls and 114Rs from the

rotation speed sensors

114L and 114R, which are the aforementioned input means. The direction and amount of rotation are determined, and a command signal 142s is issued to the electric motor 142 as necessary. The rotation of the electric motor 142 is transmitted to the rotation shaft 17 via the worm 144, the worm wheel 146, the counter shaft 145, the pinion 146, and the sector gear 148, and the cam surface 17a as described above based on the rotation of the rotation shaft 17 is transmitted. The sliding position of the shifter 9 for controlling the auxiliary clutch 8 is determined according to the tilt angle.

The command signal 142s is, for example, a voltage set to rotate the electric motor 142 to a target rotation position. This voltage is against the biasing force of the spring 9e of the shifter 9 and the fork shaft 9a of the shifter 9 and A torque sufficient to slide the fork 9b to the target sliding position is applied to the rotating shaft 17. When this voltage becomes zero, the fork shaft 9a of the shifter 9 is arranged at the maximum sliding position on the clutch separating side by the biasing force of the spring 9e. Thus, with respect to the electric actuator 141 as the auxiliary clutch actuator AA, the state in which the electric motor 142 is in the non-driven state so that the fork shaft 9a of the shifter 9 is disposed at the maximum sliding position on the clutch disengagement side, The state in which the electric motor 142 is driven so that the fork shaft 9a of the shifter 9 is slid to the clutch engagement side even slightly from the maximum sliding position on the clutch disengagement side corresponds to the inoperative state. Corresponds to the operating state.

Next, the transmission 1B will be described with reference to FIG. 3, FIG. 33, FIG. In this embodiment, the electric actuator 141 is used as the auxiliary clutch actuator AA, while the same actuator as the electric actuator 141 is used as the steering actuators SAL and SAR.

The controller 10 steers based on the input signals 111 s, 112 s, 113 s, 114 Ls, 114 Rs from the potentiometer 11 p of the steering lever 11 base, which is the input means, the switch 112, the dial 113, and the rotation speed sensors 114L, 14R. The direction and amount of rotation of the electric motor 142 of the

electric actuators

141L and 141R are determined, and command signals 142Ls and 142Rs are issued to the electric motors 142 as necessary. The rotation of the electric motor 142 of each of the steering

electric actuators

141L and 141R is transmitted to the rotation shaft 30 via the worm 144, the worm wheel 146, the counter shaft 145, the pinion 146, and the sector gear 148. The sliding position of the shifter 5 based on the rotation is determined.

The command signals 142Ls and 142Rs are, for example, voltages set so as to rotate the respective electric motors 142 to the target rotation positions. These voltages are against the urging force of the springs 5a of the

shifters

5L and 5R. A torque sufficient to slide the shifter 5 to a target sliding position is applied to the rotating shaft 30. When this voltage becomes zero, the shifter 5 is arranged at the maximum sliding position on the inner side by the biasing force of the spring 5a.

As described above, in the transmission 1B, the steering actuators SAL and SAR for controlling the left and

right shifters

5L and 5R and the auxiliary clutch actuator AA are all electric actuators 141, so that the steering is compared with the steering control system 1A. Therefore, the hydraulic pump 31, the directional control valve 32, and the variable relief valve 33 that constitute the hydraulic circuit for controlling the actuator for use are not required, which is advantageous for making the actuator set 2 compact.

A control flowchart executed by the controller 10 in the

transmissions

1A and 1B having the above-described configuration is shown in FIG. 35, which will be described. First, the controller 10 reads the input signal 112s from the switch 112, and determines whether the control of the auxiliary clutch 8 is set to the automatic mode (whether the switch 112 is set to the “ON” position) (step). S01). When the automatic mode is not set (the switch 112 is set to the “OFF” position) (NO in step S01), the input signal 113s from the dial 113 is read, and the joining force F of the auxiliary clutch 114 is set to the dial 113. The auxiliary clutch electronic control actuator AA is controlled so as to be the set value Fs corresponding to the set position. For example, the setting value Fs is 0 when the dial 13 is set to the “0” position. In this case, the auxiliary clutch electronic control actuator AA is deactivated, and the fork shaft 9a of the shifter 9 is disengaged from the clutch. The auxiliary clutch 8 is disengaged at the maximum sliding position on the side (see the dial 13 and the shifter 9 shown in FIG. 1). The setting value Fs when the dial 113 is set at the “Fmax” position corresponds to the maximum value Fmax of the bonding force F. In this case, the auxiliary clutch electronic control actuator AA is activated, the fork shaft 9a of the shifter 9 is arranged at the maximum sliding position on the clutch engagement side, and the engagement force F of the auxiliary clutch 9 is maximized (see FIG. 10). See shifter 9 shown).

When the control of the auxiliary clutch 8 is set to the automatic mode (the switch 12 is set to the “ON” position) (YES in step S01), the auxiliary clutch electronic control actuator AA is set in the operating state, and the auxiliary clutch The joining force F of 8 is set to a predetermined value Fv (a value greater than 0) set for the automatic mode (step S03). Next, in order to detect the tilt angle T of the steering lever 11, the input signal 11s of the potentiometer 11p is read. When the tilt angle T is 0, that is, when the steering lever 11 is in the straight traveling position (YES in step S04), the steering electronic control actuators SAL and SAR are deactivated (step S05). As a result, the left and

right shifters

5L and 5R are arranged at the maximum inner sliding positions (the left shifter 5L is the sliding right end position and the right shifter 5R is the sliding left end position), and the both

side clutches

6L and 6R are joined. Is done.

In this way, at the stage before determining whether to move the vehicle straight or turn based on the detection of the tilt angle T of the steering lever 11, if the automatic mode is set, the joining force F of the auxiliary clutch 8 is set to a predetermined value Fv. Thus, even when one axle 4 is likely to be slipped during straight traveling, a part of the driving force applied to the other axle 4 via the auxiliary clutch 8 is obtained. It is transmitted to the one axle 4 so that it does not become such a slip state or can be easily detached even if it becomes a slip state.

When the steering lever 11 is rotated from the straight position (NO in step S04), the steering electronic control actuator SA inside the turning is operated while the steering outside electronic control actuator SA remains in an inoperative state. (Steps S07 and S13). Depending on the tilting angle T of the steering lever 11, the operating amount of the steering electronic control actuator SA (if the hydraulic cylinder 34, the amount of expansion of the piston rod, if the actuator 141 with electric motor, the voltage applied to the electric motor 142 Amount) is determined, and the shifter 5 on the inner side of the turning is arranged at the sliding position corresponding to the operation amount. If the tilt angle T is less than the maximum value Tmax (YES in step S06), the steering lever is used to determine the rotational speed of the axle 4 inside the turn or the ratio of the rotational speed of the axle 4 inside the turn to the axle 4 outside the turn. 11 is compared with the actual value Sa calculated from the input signals 114Ls and 114Rs from the

rotational speed sensors

114L and 114R, and the difference between the actual value Sa and the target value St is compared. If there is, control is performed to adjust the amount of torque transmitted between the left and right drive trains 3L and 3R by adjusting the joining force F of the auxiliary clutch 8 to reduce or eliminate the difference.

That is, when there is no difference between the actual measurement value Sa and the target value St during the turning of the vehicle (including the case where the difference is within the allowable range) (YES in step S08), the vehicle has the target turning radius. Since the vehicle is turning, the current operating state of the auxiliary clutch electronic control actuator AA is maintained, and the joining force F of the auxiliary clutch 8 is maintained at the current value (step S09).

If the actually measured value Sa during turning is larger than the target value St (YES in step S10), the rotational speed (rotational speed ratio) of the axle 4 inside the turn is too high and the vehicle turns with a turning radius larger than the target turning radius. Therefore, the operation amount of the auxiliary clutch electronic control actuator AA is reduced, that is, the voltage as the command signal 142s applied to the electric motor 142 of the actuator 141 as the auxiliary clutch electronic control actuator AA is reduced, and the shifter The fork shaft 9a is slid to the clutch disengagement side, the joining force F of the auxiliary clutch 8 is reduced (step S11), and the transmission torque from the drive train 3 on the outside of the turn to the drive train 3 on the inside of the turn is reduced. . As a result, the rotational speed (rotational speed ratio) of the axle 4 inside the turn is reduced, and the turning radius is reduced to approach the target turning radius.

On the other hand, if the actual measurement value Sa is equal to or less than the target value St (NO in step S10), the rotational speed (rotational speed ratio) of the axle 4 inside the turn is too low and the vehicle turns with a turning radius larger than the target turning radius. Therefore, the operation amount of the auxiliary clutch electronic control actuator AA is increased, that is, the voltage as the command signal 142s applied to the electric motor 142 of the actuator 141 as the auxiliary clutch electronic control actuator AA is increased, and the shifter 9 The fork shaft 9a is slid to the clutch engagement side, the engagement force F of the auxiliary clutch 8 is increased (step S12), and the transmission torque from the outer drive train 3 to the inner drive train 3 is increased. As a result, the rotational speed (rotational speed ratio) of the axle 4 inside the turn is increased, and the turning radius is increased to approach the target turning radius.

When the tilt angle T of the steering lever 11 is the maximum value Tmax (NO in step S06), the operation amount of the steering electronic control actuator SA inside the turning is maximized, and the side brake 7 inside the turning is completely applied. (The braking force applied to the drive train 3 and the axle 4 inside the turn is maximized). At the same time, the auxiliary clutch electronic control actuator AA is deactivated and the auxiliary clutch 8 is disengaged, so that the braking force of the side brake 7 on the inside of the turn applied to the axle 4 on the inside of the turn is applied to the drive train 3 and the axle 4 on the outside of the turn. And the durability of the auxiliary clutch 8 is improved.

Next, the parking brake operation using the side clutch / side brake system in the

transmissions

1A and 1B will be described with reference to FIGS. Conventionally, in vehicles equipped with a transmission that uses a side clutch / side brake steering control system, both the left and right side brakes are applied simultaneously, or a braking force is applied to both axles separately from the left and right side brakes. A method of providing a configured parking brake on a vehicle has been applied. However, if the left and right side brakes are applied simultaneously, the right and left side clutches will be disengaged at the same time (both axles will be in a non-driven state) immediately before the left and right side brakes are applied. This was a factor such as blurring of the posture of the vehicle due to a delay in starting braking. On the other hand, providing a parking brake separately is disadvantageous in terms of cost and downsizing of the transmission.

Here, by setting the joining force F of the auxiliary clutch 8 to the maximum value Fmax, the two

drive trains

3L and 3R and the two

axles

4L and 4R are completely deflocked, and one of the left and right drive trains 3L and 3R When the vehicle is braked, the braking force extends to the other via the auxiliary clutch 8, and both the

axles

4L and 4R are braked simultaneously to function as a parking brake.

That is, the vehicle equipped with the

transmission

1A or 1B according to the present embodiment is provided with a parking brake pedal 115 as shown in FIG. 36 as a parking brake operation tool, and the parking brake switch 115a is turned on depending on whether or not the stepping operation is performed.・ OFF can be switched. Then, a signal 115s indicating ON / OFF of the parking brake switch 115a is input to the controller 10 in the steering control system 1.

38 is incorporated in the control flow of the vehicle turning controller 10 as shown in FIG. 35 so that the steering control system 1 functions as a parking brake. That is, when it is detected that the parking brake switch 115a is ON (step S21, ON), the controller 10 selects one of the pair of steering electronic control actuators SAL and SAR (in the embodiment of FIG. 37). The steering electronic control actuator SAR is held in a non-actuated state, and the shifter 5 is held at the maximum sliding position on the inner side as described above, and the other (the electronic control actuator for steering in the embodiment shown in FIG. 37). For SAL), the shifter 5 is placed in the maximum sliding position on the outer side in a full operation state. Then, the auxiliary clutch electronic control actuator AA is operated so that the joining force F of the auxiliary clutch 8 becomes the maximum value Fmax (step S22). When the parking brake 115 is not activated (the parking brake switch 115a is OFF), the process proceeds to an ON / OFF detection step (step S01) of the switch 112 in the control flow of FIG.

Next, the embodiment shown in FIGS. 39 and 40 will be described. In the present embodiment, correction control of the joining force of the auxiliary clutch 8 is performed based on detection of the leaning state of the vehicle in the front-rear direction. First, the purpose will be described. When turning on sloping ground, especially when crossing sloping ground, the vehicle weight is applied to the axle 4 located on the lower side of the sloping ground, and the turning trajectory is assumed especially for the axle 4 inside the turning where the side clutch 6 is disconnected. There is a high possibility of shifting to a lower side of the slope than what was being done. That is, when turning on a slope that rises forward, the axle 4 on the inside of the turn tends to shift backward, which is on the low position side. On the other hand, if turning on a slope that is lowered forward, the axle 4 on the inside of the turn It tends to shift forward. It is considered that the deviation due to the own weight is eliminated by increasing the traveling ability of the axle 4 inside the turn in the traveling direction. To improve the traveling ability, the drive train 3 outside the turn via the auxiliary clutch 8 is used. It is conceivable to increase the torque to the drive train 3 inside the turning. Therefore, in the steering control system 1 according to the present embodiment, when the setting of the engagement force F of the auxiliary clutch 8 is set to the automatic mode, when the vehicle is in an inclined state, to correct the engagement force of the auxiliary clutch 8, The auxiliary clutch electronic control actuator AA is controlled.

That is, in the present embodiment, as shown in FIG. 39, a tilt sensor 116 that detects a tilt angle (pitch angle) P in the front-rear direction of the vehicle is provided in the vehicle as input means to the controller 10. In this case, a detection signal 116 s of the inclination angle P is input from the inclination sensor 116. As shown in FIG. 40, the auxiliary clutch electronic control actuator AA is operated based on the automatic mode ON (YES in step S01), and the joining force F of the auxiliary clutch 8 is set to a predetermined value Fv (step S03). ), The controller 10 reads the input detection signal 116s, and the vehicle inclination angle P is 0 (including a case where the vehicle is at a value within an allowable range that is close to 0 and does not require correction of the bonding force F). Whether or not (step S31).

If it is determined that the vehicle is in a horizontal state (inclination angle P is 0) (YES in step S31), the engagement state of the auxiliary clutch 8 set so that the engagement force F becomes the predetermined value Fv is maintained. Then, the process proceeds to a reading process (step S04) of the tilt angle T of the steering lever 11 for the straight traveling or turning control of the vehicle. If it is determined that the vehicle is not in a horizontal state (inclination angle P is not 0) (NO in step S31), controller 10 increases the voltage applied to electric motor 142 of actuator 141 as auxiliary clutch electronic control actuator AA. A command signal 142s is issued, the shifter 9 is slid, and the joining force F of the auxiliary clutch 8 is increased to a value corresponding to the inclination angle P (step S32). In this way, when the joining force F of the auxiliary clutch 8 that was initially set to the predetermined value Fv is increased to a value corresponding to the inclination angle P, the reading process of the inclination angle T of the steering lever 11 for the straight traveling or turning control of the vehicle. The process proceeds to (Step S04).

While the vehicle is traveling in the automatic mode, the detection signal 116s from the tilt sensor 116 is continuously input to the controller 10, and the controller 10 determines the joining force F of the auxiliary clutch 8 in response to the change in the tilt angle P. Continue to control the auxiliary clutch electronic control actuator AA to adjust. On the other hand, when the switch 112 is OFF (OFF in step S01), the joining force F of the auxiliary clutch 8 is fixed to the set value Fs at the dial 113 regardless of the change in the vehicle inclination state ( Step S02).

As described above, the vehicle steering system according to the present invention is applied to a vehicle transmission or the like that employs a side clutch / side brake steering system, and is a typical vehicle to be applied. Can be applied to any type of vehicle that employs a side-clutch / side-brake vehicle steering system.

DESCRIPTION OF SYMBOLS 1 Transmission 2 Vehicle steering actuator set 3 (3L * 3R) Drive train 4 (4L * 4R) Axle 5 (5L * 5R) Shifter 6 (6L * 6R) Side clutch 7 (7L * 7R) Side brake 8 Auxiliary clutch 9 Shifter 10 Controller 11 Steering lever (steering operation tool)
12 Lever (Auxiliary clutch engagement force setting means)
13 Pedal (auxiliary clutch operating tool)
18 (18A / 18B) Checking mechanism

Claims

A side clutch and a side brake are provided in each of a pair of parallel drive trains for distributing power to a pair of axles, the side clutch inside the turn is turned off in accordance with the operation of the steering operation tool, and the side brake is In the vehicle steering system configured to operate, an auxiliary clutch for transmitting torque between the pair of drive trains and a variable joining force for increasing the joining force of the auxiliary clutch A vehicle steering system characterized in that an auxiliary clutch operating tool is provided, and a check mechanism is provided to prevent simultaneous operation of the side brake and increase in the engagement force of the auxiliary clutch.
The check mechanism is configured such that when the auxiliary clutch operating tool is operated to increase the engagement force of the auxiliary clutch, the side brake inside the turning is not activated regardless of the operation of the steering operating tool. The vehicle steering system according to claim 1, wherein:
Auxiliary clutch engagement force setting means for setting the engagement force of the auxiliary clutch to a predetermined value is provided, and the auxiliary clutch operating tool sets the engagement force of the auxiliary clutch by the auxiliary clutch engagement force setting means. The vehicle steering system according to claim 2, wherein the vehicle steering system is operated to increase the predetermined value.
The check mechanism is configured such that when the steering operation tool is operated to operate the side brake inside the turning, the joining force of the auxiliary clutch is not increased regardless of the operation of the auxiliary clutch operation tool. The vehicle steering system according to claim 1.
Auxiliary clutch engagement force setting means for setting the engagement force of the auxiliary clutch to a predetermined value is provided, and the auxiliary clutch operating tool sets the engagement force of the auxiliary clutch by the auxiliary clutch engagement force setting means. The vehicle steering system according to claim 4, wherein the vehicle steering system is operated to increase the predetermined value.