JPH0565758U - Work vehicle drive transmission structure - Google Patents

Abstract

(57) [Abstract] [Purpose] In the traveling power transmission structure of a work vehicle equipped with a hydraulic side brake for pivot turning, or a hydraulic reverse clutch for super pivot turning, during or after pivot turning. Configured so that the traveling speed is automatically decelerated during turning
In addition, the deceleration operation amount can be easily changed. [Structure] A hydraulic cylinder 7 capable of contact-pushing and operating a shift operation unit 6 of a continuously variable transmission 1 for traveling at a low speed side, and when a side brake 28 or a reverse clutch 30 is supplied with operating oil for operation, This hydraulic oil is also supplied to the hydraulic cylinder 7 so that the gear shift operating portion 6 is pressed and pushed to the low speed side by the hydraulic cylinder 7 during turning or super turning. . And the hydraulic cylinder 7
Is configured so that its position can be changed in its extension or contraction direction, and the amount of deceleration operation by the hydraulic cylinder 7 can be adjusted to be large or small.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a traveling power transmission structure of a work vehicle equipped with a pair of left and right traveling devices of a crawler type or a multi-wheel type such as four wheels on one side.

[0002]

[Prior Art]

 One of the above-mentioned work vehicles is a combine equipped with a pair of left and right crawler type traveling devices, and an example of the traveling power transmission structure is disclosed in JP-A-3-104784. This structure is equipped with a hydraulic side brake and a reverse rotation clutch for turning.By braking one traveling device with the side brake, a lateral turn can be performed, and by using the reverse clutch, one traveling device can be operated. It is configured so that super-revolution turning can be performed by driving in the reverse direction.

In this structure, when operating oil is supplied to the side brake or the reverse clutch, the operating oil is branched and supplied to the hydraulic cylinder (53 in FIG. 1 and FIG. 6 of the publication). Is configured as follows. As a result, the hydraulic cylinder expands during a turning turn or a super turning turn, and the continuously variable transmission for traveling is automatically decelerated to the low speed side. It is configured to prevent the engine from stopping when turning. This is because the pivot turning and the super turning are performed by pushing the soil on the ground sideways by the traveling device, and a large load is applied. Further, in the structure of the above publication, when there is no danger of the engine stopping even if the solid turning or the super turning is performed as it is on a paved road or the like, the deceleration operation is not performed even if the hydraulic cylinder is extended (the above publication). (See FIG. 5).

[0004]

[Problems to be solved by the device]

 In the above-mentioned structure, when the vehicle is turning to the ground or super-ground, the hydraulic cylinder automatically decelerates the running continuously variable transmission to the specified low speed position, and it is not decelerated at all. It is configured to switch to two states. Therefore, in the case of work vehicles traveling on various work sites such as soft ground, dry paddy field, grassland, and paved roads, there may be cases where the above-mentioned selective switching between the two states cannot deal with the situation. An object of the present invention is to configure the structure, which is automatically decelerated during the turning or super turning as described above, so as to be applicable to various work sites.

[0005]

[Means for Solving the Problems]

 A feature of the present invention is that the traveling power transmission structure of the work vehicle as described above is configured as follows. In other words, it is equipped with a hydraulic cylinder that allows the shifting operation part of the continuously variable transmission for traveling to be pushed and pressed toward the low speed side, and is a supply path that is diverged from the supply path of the hydraulic oil to the turning side brake or reverse clutch. Is connected to a hydraulic cylinder, and when the operating pressure of the side brake or the reverse clutch exceeds a set value, the hydraulic cylinder expands or contracts to press and operate the gear shifting operation unit to the low speed side. The hydraulic cylinder is configured so that its position can be changed in the extension or contraction direction, and an operation means for changing the position of the hydraulic cylinder is provided.

[0006]

[Action]

 With the above-mentioned structure, if hydraulic oil is supplied to the side brake or the reverse clutch for performing the pivotal turning or the super pivotal turning, this hydraulic oil is also supplied to the hydraulic cylinder. As a result, the hydraulic cylinder expands or contracts, and the speed change operation unit of the continuously variable transmission is pressed and pressed toward the low speed side, and automatic deceleration operation is performed. In this case, by changing the position of the hydraulic cylinder along the extension or contraction direction of the hydraulic cylinder by the operating means, it is possible to change the interval between the contact portion between the hydraulic cylinder and the gear shift operating portion before the operation. That is, even if the hydraulic cylinder extends or contracts to the end of its stroke, the amount by which the speed change operation unit is operated to the low speed side changes. As a result, by changing the position of the hydraulic cylinder according to the condition of the work site, the amount of deceleration when turning the ground or turning the super ground is set to an appropriate value according to the condition of the work site. You can. In this case, if the main purpose is to prevent the engine from stopping during a turning turn or a super turning turn, set it so that the hydraulic cylinder will decelerate greatly in soft areas with high resistance such as in wetlands. The setting should be made so that the vehicle does not slow down too much at a work site with low resistance. On the other hand, if the main focus is on the stability and safety of the aircraft during turning or super turning, then set it so that the hydraulic cylinder will not slow down much in soft areas with high resistance such as wetlands. In a work area with low resistance such as a paved road, it may be set so that the speed is greatly reduced.

As a means for changing the deceleration amount, a means for changing the expansion / contraction amount or contraction amount of the hydraulic cylinder while keeping the position of the hydraulic cylinder as it is conceivable. A hydraulic control structure for controlling the expansion / contraction amount or the contraction amount is required in the hydraulic circuit, and the structure becomes complicated. On the other hand, mechanically changing the position of the hydraulic cylinder as in the structure of the present invention can be easily configured without the need for a complicated hydraulic control structure.

[0008]

[Effect of the device]

 As described above, in the case of automatically decelerating the traveling speed during a turning turn or a super turning turn, it is possible to set the deceleration amount to an appropriate one according to various work sites. As a result, the turning performance of the work vehicle could be improved. Further, when this structure is obtained, the structure can be simply configured without the need for a complicated hydraulic control structure, which is advantageous in terms of manufacturing cost.

[0009]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 shows a structure inside a transmission case 8 of a traveling system in a combine, which is an example of a work vehicle, in which power from an engine (not shown) is provided with a belt transmission mechanism (not shown) equipped with a tension clutch. Through the input pulley 2 of the hydrostatic continuously variable transmission 1, and the power from the output shaft 3 of the continuously variable transmission 1 is transmitted through the first transmission shaft 4 to the reaper (not shown). Be transmitted).

Power from the first transmission shaft 4 is transmitted to the second transmission shaft 11 via the first gear 9 and the second gear 10. A shift gear 14 is slidably fitted to the second transmission shaft 11 in a spline structure, and a high speed gear 16 and a low speed gear 17 are fixed to a third transmission shaft 15 corresponding thereto. With the above-described structure, the shift gear 14 is slid to engage with the high speed gear 16 or the low speed gear 17, so that the power can be shifted into two levels, high and low. This power is the third gear that meshes with the low speed gear 17. 19 is transmitted.

A right side gear 21R and a left side gear 21L are fitted to the support shaft 20 supporting the third gear 19 so as to be rotatable relative to each other, and an input gear 23 of the left and right axles 22 is connected to the left and right side gears 21R, 21L is always occluded. As a result, the right or left side gears 21R and 21L are slid with respect to the third gear 19 to engage / separate, and power transmission and transmission interruption operations are performed on the crawler type traveling device 24. Side clutches 25R and 25L are formed between the gear 19 and the left and right side gears 21R and 21L.

Next, a structure for braking one traveling device 24 will be described. As shown in FIG. 4, the right fourth gear 26R and the left fourth gear 26L are rotatably supported by the support shaft 20 while the pair of fifth gears 29 fixed to the fourth transmission shaft 27 are supported. The right fourth gear 26R and the left fourth gear 26L are engaged with each other. A multi-plate hydraulically operated side brake 28 is provided at one end of the fourth transmission shaft 27. As a result, the right side gear 21R or the left side gear 21L is separated from the third gear 19 so as to be engaged with the right fourth gear 26R or the left fourth gear 26L, and the side brake 28 is turned on to operate the one side gear. The traveling device 24 can be braked. And, this is a turning state.

Next, a structure for reversing the traveling device 24 on one side will be described. As shown in FIG. 4, a sixth gear 37 meshing with the high speed gear 16 of the third transmission shaft 15 is fitted onto the fourth transmission shaft 27 so as to be rotatable relative to the sixth gear 37 and the fourth transmission shaft 27. A reverse clutch 30 is provided between and. As a result, when the reverse clutch 30 is operated with the right side gear 21R or the left side gear 21L engaged with the right fourth gear 26R or the left fourth gear 26L as described above, the power from the high speed gear 16 is generated. Is in the reverse rotation state, and is decelerated to 1/2 and transmitted to one traveling device 24. And this is a super-confidential turning state.

Next, a structure for driving one traveling device 24 in the normal direction at a lower speed than the other will be described. As shown in FIG. 4, the first sprocket 13 is fixed to the third transmission shaft 15, and the second sprocket 38 is externally fitted to the fourth transmission shaft 27 so as to be rotatable relative to each other. A transmission chain 40 is wound around 38. The slow swing clutch 12 is provided between the second sprocket 38 and the fourth transmission shaft 27. As a result, when the right or left side gear 21R, 21L is engaged with the right or left fourth gear 26R, 26L and the slow turning clutch 12 is engaged and operated, the forward rotation power from the third transmission shaft 15 is reduced to 1 /. It is decelerated to 2 and transmitted to one of the traveling devices 24. And, this is a gentle turning state.

Next, a working oil supply structure for the hydraulic cylinders 31R, 31L that slides the left and right side gears 21R, 21L, the side brake 28, the slowly turning and reverse clutches 12, 30 will be described. As shown in FIG. 3, the hydraulic oil from the pump 32 is supplied to the hydraulic cylinders 31R and 31L for the left and right side gears 21R and 21L via the first switching valve 33, and the oil from the side surfaces of the hydraulic cylinders 31R and 31L is supplied. The passage 34 is connected to the side brake 28, the second switching valve 35 for the slow-turn and reverse rotation clutches 12, 30. The oil passage 34 is connected with a side brake 28 and a variable relief valve 36 for the gentle turning and reverse rotation clutches 12 and 30.

Next, the operation of the first switching valve 33, the second switching valve 35, and the variable relief valve 36 will be described. As shown in FIG. 3, the operation position of the switching lever 18 is input to the control device 5, and the electromagnetically operated second switching valve 35 is controlled by the control device 5 based on the operation position of the switching lever 18. Switch to a gently swiveling position 35a for supplying hydraulic oil to the swivel clutch 12, a solid swivel position 35b for supplying hydraulic oil to the side brakes 28, and a super-spinning position 35c for supplying hydraulic oil to the reverse rotation clutch 30. Operated. The operation lever 39 for turning operation, the first switching valve 33, and the variable relief valve 36 are mechanically linked via a first linkage mechanism 41 and a second linkage mechanism 42.

The state shown in FIG. 3 is a state in which the switching lever 18 is operated to the pivot position, and the second switching valve 35 is operated to the pivot position 35b. In this state, when the operating lever 39 is operated from the neutral position N to the first turning position R1 on the right or the first turning position L1 on the left, only the first switching valve 33 is operated and the hydraulic cylinder 31R or 31L is operated. , The right or left side gear 21R, 21L, which is in mesh with the third gear 19 via the right or left operation portion 46R, 46L, is separated from the third gear 19 to the right or left fourth gear 26R, 26L. Bite into.

In this case, since the variable relief valve 36 is in the fully open state and the side brake 28 is in the open state, the transmission to the right or left traveling device 24 is cut off (the side clutch 25R or 25L is not connected). (Transmission cutoff state) and the aircraft slowly turns to the right or left. The sequence valve 47 provided in the oil passage 34 supplies the pressure required for the right or left side gear 21R, 21L to completely mesh with the right or left fourth gear 26R, 26L. , 31L.

Next, when the operating lever 39 is operated from the right or left first turning position R1, L1 to the right or left second turning position R2, L2, the right or left side gears 21R, 21L move to the right. Alternatively, when the left fourth gears 26R and 26L are engaged with each other and the second switching valve 35 is operated to the turning position 35b, the variable relief valve 36 is gradually operated from the fully opened state to the closed side. As a result, the side brake 28 starts to act and the right or left traveling device 24 is gradually braked, and the aircraft makes a right turn or left turn. Then, the braking force of the side brake 28 becomes maximum at the second turning position R2, L2 to the right or left of the operating lever 39.

Next, when the switching lever 18 is operated to the super-oriented turning position, the second switching valve 35 is switched to the super-oriented turning position 35c. In this state, when the operating lever 39 is operated from the neutral position N 1 to the first turning position R1 or L1 on the right or left, the transmission cut-off state of the right or left side clutch 25R, 25L appears as described above.

Next, when the operating lever 39 is operated from the right or left first turning position R1, L1 to the right or left second turning position R2, L2, the right or left side gear 21R, 21L is moved to the right. Alternatively, in the state where the left fourth gears 26R and 26L are engaged with each other and the second switching valve 35 is operated to the super-spinning rotation position 35c, the variable relief valve 36 is gradually closed from the fully opened state as described above. Will be operated by. As a result, the reverse rotation clutch 30 starts to operate, and the right or left traveling device 24 is gradually driven in reverse rotation, and the aircraft makes a super turning turn to the right or left. Then, the reverse rotation speed becomes maximum at the right or left second turning position R2, L2 of the operation lever 39.

Next, when the switching lever 18 is operated to the gentle turning position, the second switching valve 35 is switched to the gentle turning position 35a. In this state, when the operating lever 39 is operated from the neutral position N to the first turning position R1, L1 on the right or left, the transmission cutoff state of the right or left side clutch 25R, 25L appears as in the above.

Next, when the operating lever 39 is operated from the right or left first turning position R1, L1 to the right or left second turning position R2, L2, the right or left side gear 21R, 21L is moved to the right. Alternatively, in a state where the left fourth gears 26R and 26L are engaged with each other and the second switching valve 35 is operated to the slow turning position 35a, the variable relief valve 36 is gradually operated from the fully opened state to the closed side as described above. Go away. As a result, the slow turning clutch 12 starts to act, and the right or left traveling device 24 is gradually driven to rotate in the forward direction at a low speed, so that the aircraft slowly turns right or left. Then, at the right or left second turning position R2, L2 of the operation lever 39, the slow turning speed becomes maximum.

Next, an automatic deceleration structure at the time of turning the earth and turning the super earth will be described. As shown in FIGS. 1 and 3, the arm 6a fixed to the speed change lever 6 (corresponding to the speed change operation portion) and the continuously variable transmission 1 are interlockingly connected by the link rod 44. A gear shift operation is performed from the neutral stop position N to the forward maximum speed position F and the reverse maximum speed position R. A single-acting hydraulic cylinder 7 is provided for the speed change lever 6, and the oil passage 43 (corresponding to the supply passage of the hydraulic oil to the side brake 28 and the reverse rotation clutch 30) is supplied to the oil passage 43 (supply). (Corresponding to the passage) is branched, and this oil passage 43 is connected to the hydraulic cylinder 7. As shown in FIG. 1, a pair of long holes 45a are provided in a bracket 45 fixed to the machine body, and a hydraulic cylinder 7 is fixed to the portion of the long holes 45a by a bolt / nut 48. As a result, the fixed position of the hydraulic cylinder 7 can be changed and adjusted along the expansion / contraction direction of the piston 7a (vertical direction on the paper surface) (corresponding to the operating means).

The piston 7a of the hydraulic cylinder 7 is urged toward the contraction side by an internal spring, and the piston 7a contracts at the position where the hydraulic cylinder 7 is closest to the arm 6a as shown in FIG. In this case, even if the gear shift lever 6 is operated to the forward maximum speed position F, the arm 6a of the gear shift lever 6 does not come into contact with the piston 7a. Then, as shown in FIG. 1, the piston 7a of the hydraulic cylinder 7 extends to its stroke end in a state where the speed change lever 6 is operated to the forward side with the hydraulic cylinder 7 being closest to the arm 6a. Then, the speed change lever 6 is pressed and operated to a predetermined low speed position FL.

With the above structure, when the operation lever 39 is operated to the right or left second turning position R2 or L2 while the switching lever 18 is being operated to the pivot turning position and the super pivot turning position, The hydraulic oil is supplied to the brake 28 or the reverse clutch 30, and the hydraulic oil is put in the on state. At the same time, hydraulic oil is also supplied to the hydraulic cylinder 7 to extend the piston 7a, so that the speed change lever 6 and the continuously variable transmission 1, which are operated forward, are automatically moved to a predetermined low speed position FL. It is decelerated to.

In this case, if the position of the hydraulic cylinder 7 is changed from the position shown in FIG. 1 where the hydraulic cylinder 7 is closest to the arm 6a to the lower side according to the state of the work site, the piston 7a of the hydraulic cylinder 7 is moved. Even when extended to the stroke end, the speed change lever 6 and the continuously variable transmission 1 are not decelerated to the predetermined low speed position FL. Then, as shown in FIG. 2, when the position of the hydraulic cylinder 7 is set to the position farthest from the arm 6a (the lowermost position on the paper surface), even if the piston 7a of the hydraulic cylinder 7 extends to its stroke end, the piston 7a Does not come into contact with the arm 6a, and the deceleration operation of the transmission lever 6 and the continuously variable transmission 1 is not performed.

As a result, by adjusting the position of the hydraulic cylinder 7 up and down, the speed at which the speed change lever 6 and the continuously variable transmission 1 are decelerated at the time of the pivot turning and the super pivot turning is set to the forward maximum speed position. The setting can be arbitrarily changed between F and the predetermined low speed position FL. In this case, it may be set so that the vehicle is decelerated to a predetermined low speed position FL in a soft land such as a wetland and the deceleration operation is not performed on a pavement or the like. Then, in a dry field, a grassland or the like, it may be set so as to be decelerated to an intermediate position between the forward maximum speed position F and a predetermined low speed position FL.

As shown in FIG. 3, a normally open and electromagnetically operated on-off valve 49 is provided in the oil passage 43, and a push-on / push-off type push button 39a is provided at the upper end of the operation lever 39. Has been. As a result, when the switch lever 18 is operated to the pivot turning position and the super pivot turning position and the push button 39a of the operating lever 39 is pushed in to be turned on, the on-off valve 49 opens. To be operated. As a result, the deceleration operation of the speed change lever 6 and the continuously variable transmission 1 is not performed during the solid turning and the super turning. Further, the open / close valve 49 is operated to the open position even when the switching lever 18 is operated to the gentle turning position. As a result, the deceleration operation of the transmission lever 6 and the continuously variable transmission 1 is not performed even during a gentle turn.

[Other Embodiments] In the structure shown in FIG. 1, the deceleration operation of the transmission lever 6 and the continuously variable transmission 1 is performed by the extension operation of the piston 7a of the hydraulic cylinder 7. However, the hydraulic cylinder It may be configured that the deceleration operation of the speed change lever 6 and the continuously variable transmission 1 is performed by the contraction operation of the piston 7a of No. 7. In the structure shown in FIG. 1, the position of the hydraulic cylinder 7 is changed by loosening and tightening the bolts and nuts 48. However, a position change lever (not shown) (operation not shown) provided in the control section of the aircraft is used. The position of the hydraulic cylinder 7 may be changed in conjunction with this by operating (corresponding to the means). In the structure shown in FIGS. 3 and 4, the slow swing clutch 12 for slow swing and the reverse clutch 30 for super-spot swing are not equipped, but only the side brake 28 for swing swing, The slow swing clutch 12 and the side brake 28 for the pivot rotation may not be provided, but only the reverse clutch 30 for the super pivot rotation may be provided.

It should be noted that reference numerals are added to the claims of the utility model for convenience of comparison with the drawings, but the invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a side view of a hydraulic cylinder for deceleration operation and a part of an arm of a speed change lever in the vicinity of the arm.

FIG. 2 is a side view showing a state in which the hydraulic cylinder is farthest from the arm of the shift lever from the state shown in FIG.

FIG. 3 is a hydraulic circuit diagram of a slow swing clutch, a side brake, a reverse clutch and a hydraulic cylinder.

FIG. 4 is a schematic vertical sectional front view showing a transmission structure in a mission case.

[Explanation of symbols]

 1 continuously variable transmission 6 gear shift operation part of continuously variable transmission 7 hydraulic cylinder 24 traveling device 28 side brake 30 reverse clutch 34, 43 hydraulic oil supply path

Claims (1)

[Scope of utility model registration request] 1. A hydraulic side brake comprising a continuously variable transmission (1) for transmitting driving power to a pair of left and right traveling devices (24), and braking one selected traveling device (24). (28) or a traveling power transmission structure for a working vehicle, comprising a hydraulic reverse clutch (30) capable of transmitting reverse power to one selected traveling device (24), the continuously variable transmission A hydraulic cylinder (7) capable of pushing and operating the speed change operation part (6) of (1) at a low speed side is provided, and a hydraulic oil supply path (34) to the side brake (28) or the reverse rotation clutch (30). When the operating pressure of the side brake (28) or the reverse rotation clutch (30) exceeds a set value, the hydraulic cylinder (7) is extended by connecting the supply path (43) branched from the hydraulic cylinder (7) to the hydraulic cylinder (7). Alternatively, the gear shift operation part (6 Of the hydraulic cylinder (7) so that the hydraulic cylinder (7) can be moved in the direction of extension or contraction, and the position of the hydraulic cylinder (7) can be changed. A drive transmission structure for a work vehicle equipped with means.