JP2635807B2 - Work vehicle steering operation structure - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering operation structure of a working vehicle provided with a pair of left and right crawler or multi-wheel traveling devices.

[Conventional technology]

An example of the work vehicle described above is a combine equipped with a crawler-type traveling device. In such a combine, a low-speed transmission mechanism including a first hydraulic clutch capable of transmitting forward rotation power at a speed lower than that of the selected traveling device to the other traveling device, and a reverse rotation power to the selected traveling device. There is a vehicle in which a reverse rotation transmission mechanism having a second hydraulic clutch capable of transmission is provided in parallel with the traveling device. This makes it possible to surely make a gentle turn even on soft ground by driving one of the traveling devices at low speed. Can turn.

The switching operation between the gentle turning and the super turning is performed by switching the supply direction of the operating oil to the first and second hydraulic clutches by the first switching valve, and the operating oil is changed to the first hydraulic pressure. This is performed depending on whether it is supplied to the clutch or the second hydraulic clutch. The first and second hydraulic clutches are provided with a common second switching valve for switching the supply / discharge state of the hydraulic oil, and the operation lever switches the second switching valve from the discharge state to the supply state. With this, the first or second hydraulic clutch is engaged and operated.

[Problems to be solved by the invention]

Since the turning operation using the second clutch using the second clutch can be performed with a very small radius, if the turning state suddenly appears, the aircraft may be swung, which is not preferable for safety. In view of this, as the second switching valve, a pressure increasing mechanism that can increase the pressure of the first or second hydraulic clutch in accordance with the operation position of the operation lever is employed.

Thus, if the pressure increase by the pressure increase adjustment mechanism is set to increase linearly from the O pressure in accordance with the operation position of the operation lever, the pressure is gradually changed by the operation lever near the O pressure. While turning the second hydraulic clutch, the turning radius of the swivel turn can be easily adjusted slightly and delicately.

On the other hand, the gentle turning using the first hydraulic clutch has a large turning radius, so that no particular problem occurs even if the turning state appears suddenly, but the running resistance of the field where the combine is driven is extremely low. If it is large, the following problem may occur.

In other words, if the pressure increasing characteristic of the pressure increasing adjusting mechanism is set so as to increase linearly from zero pressure in accordance with the characteristic of the second hydraulic clutch, the first hydraulic clutch is operated by the operating lever so as to perform gentle turning when traveling straight. When the on-coming operation is attempted, if the operation amount of the operation lever is not sufficient, the pressure of the first hydraulic clutch is not sufficient, and the traveling device inside the turning is stopped due to a large traveling resistance. Therefore, even if the user tries to smoothly turn slowly from the straight traveling state, the aircraft will turn with an unexpected small radius when the operation lever is slightly operated.

Therefore, instead of the first hydraulic clutch, a mechanical clutch that can selectively and promptly appear between a transmission state and a non-transmission state, such as a meshing clutch, is adopted.
This mechanical clutch can be independently switched between a transmission state and a non-transmission state by an operation system different from the operation system of the second hydraulic clutch to avoid the above-described problem. Can be

However, in this case, since the operation system of the mechanical clutch and the operation system of the second hydraulic clutch are provided in parallel, for example, during turning on the ground by turning on the second hydraulic clutch, or If the mechanical clutch or the second hydraulic clutch is erroneously engaged during the gentle turning with the mechanical clutch engaged, low-speed forward rotation power and reverse rotation power are simultaneously transmitted to one traveling device. A double transmission state occurs and the transmission system is damaged. Further, for example, in the case of shifting from the super pivot turning in which the second hydraulic clutch is operated to the gentle turning in which the mechanical clutch is operated, in order to avoid the double transmission state, the operating lever is first operated. As a result, since the turning state must be completed by the second switching means after the turning operation is completed, the transition from the turning operation to the turning operation cannot be quickly performed.

According to the present invention, it is possible to quickly make a transition from a pivot turn to a gentle turn while preventing a double transmission state in which low-speed forward rotation power and reverse rotation power are simultaneously transmitted to one traveling device. It is another object of the present invention to prevent the traveling device inside the turn from stopping and turning at an unexpected small radius when performing a gentle turn in a field where running resistance is extremely large.

[Means for solving the problem]

A feature of the first invention is that the steering operation structure of the work vehicle including the pair of left and right traveling devices is configured as follows. That is, (a) a mechanical clutch capable of transmitting forward rotation power at a speed lower than the other to one selected by operating the turning operation lever of the traveling device by contact between the transmitting body and the driven body. Equipped with a low-speed transmission mechanism equipped with

[B] One of the traveling devices selected by operating the operation lever is provided with a hydraulic clutch capable of transmitting reverse rotation power.

[C] A first switching means capable of switching the operating state of the hydraulic clutch by operating the operation lever is provided in the hydraulic oil supply system for the operation of entering the hydraulic clutch.

[D] Second switching means capable of switching the low-speed transmission mechanism between a transmission state and a non-transmission state by an operation system different from the operation system of the hydraulic clutch.

[E] When the second switching means is switched to the transmission state side of the low-speed transmission mechanism, the first switching means is interlocked with this operation.
A check means for forcibly switching and holding the hydraulic clutch in a disengaged state is provided.

A feature of the second aspect of the invention resides in that a steering operation structure of a work vehicle provided with a pair of right and left traveling devices is configured as follows. That is, (f) a mechanical clutch capable of transmitting forward rotation power at a speed lower than the other to one selected by operating the turning operation lever of the traveling device by contact between the transmitting body and the driven body. Equipped with a low-speed transmission mechanism equipped with

[G] One of the traveling devices selected by operating the operation lever is provided with a hydraulic clutch capable of transmitting reverse rotation power.

[H] A first switching means capable of switching the operating state of the hydraulic clutch by operating the operation lever is provided in the operation for entering the hydraulic clutch and the hydraulic oil supply system.

[G] Second switching means capable of switching the low-speed transmission mechanism between a transmission state and a non-transmission state by an operation system different from the operation system of the hydraulic clutch.

[G] Third switching means for switching the hydraulic clutch to the unload state in response to the switching operation of the second switching means to the transmission state side of the low-speed transmission mechanism.

(Operation)

According to the first aspect of the present invention, the first clutch for reverse transmission is connected smoothly with less shock.
Even if a pressure increasing mechanism that gradually increases the pressure of the hydraulic clutch is used as the switching means, when the slow turning by the low-speed transmission mechanism appears, the low-speed transmission mechanism is switched to the transmission state in advance by the second switching means. Since the traveling device on the side driven at a low speed can be selected by operating the turning operation lever, a gentle turning can be realized at the same time. In other words, even in a field where running resistance is very large,
If the operation lever is operated while traveling straight, the slow turning can be smoothly shifted to the slow turning without the inconvenience that the aircraft turns at an unexpected small radius due to the delay in the appearance of the slow turning.

Also, when the second switching means is switched to the transmission state side of the low-speed transmission mechanism, the first switching means is forcibly switched by the restraint means in conjunction therewith, and the hydraulic clutch for reverse transmission is disengaged. Conversely, when the second switching means is switched to the non-transmission state side of the low-speed transmission mechanism, in conjunction therewith, the first switching means is released from the forcible switching operation by the restraint means, and the reverse transmission power is released. Since the hydraulic clutch is engaged, a double transmission state due to an erroneous operation or the like does not occur during the appearance of the super turning state or the gentle turning state.

In addition, when the mechanical clutch is turned on by the second switching means during the turning of the ground, the first switching means is forcibly switched by the restraining means in conjunction with this operation, and the hydraulic clutch for reverse transmission is disengaged. In this state, the pivot turn can be quickly terminated, and a gentle turn can be quickly realized by the operation of engaging the mechanical clutch. That is, the transition from the pivot turn to the gentle turn can be quickly performed without causing the double transmission state to appear.

On the other hand, according to the second aspect of the invention, in order that the hydraulic clutch for reverse rotation transmission can be smoothly connected with less shock, a pressure increasing mechanism or the like that gradually increases the pressure of the hydraulic clutch may be used as the first switching means. In the same manner as in the first aspect, when a gentle turning by the speed transmission mechanism is developed, the traveling device on the low-speed driving side is selected by operating the turning operation lever so that the gentle turning can be realized at the same time. Become. In other words, even in a field where running resistance is very large,
If the operation lever is operated while traveling straight, the slow turning can be smoothly shifted to the slow turning without the inconvenience that the aircraft turns at an unexpected small radius due to the delay in the appearance of the slow turning.

Further, when the second switching means is switched to the transmission state side of the low-speed transmission mechanism, the hydraulic clutch is switched to the unload state by the third switching means in conjunction with this, and the disengaged state of the hydraulic clutch is displayed, Conversely, when the second switching means is switched to the non-transmission state side of the low-speed transmission mechanism, the hydraulic clutch is switched to the hydraulic oil supply state by the third switching means in conjunction therewith, and the engagement state of the hydraulic clutch is changed. Since it appears, the double transmission state due to an erroneous operation or the like does not occur during the appearance of the super turning state or the gentle turning state.

In addition, when the mechanical clutch is turned on by the second switching means during the turning of the ground, the hydraulic clutch is switched to the unloading state by the third switching means, and the hydraulic clutch is turned off. As a result, the pivot turn can be quickly terminated, and a gentle turn can be quickly brought out by engaging the mechanical clutch. That is, the transition from the pivot turn to the gentle turn can be quickly performed without causing the double transmission state to appear.

〔The invention's effect〕

Therefore, while being able to prevent the transmission system from being damaged due to the double transmission state, it is possible to promptly shift from the super pivot turn to the gentle turn, and perform the gentle turn in a field where running resistance is extremely large. At this time, it is possible to avoid that the traveling device inside the turn stops and turns at an unexpected small radius.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 shows a structure inside a transmission case (8) of a traveling system of a combine, which is one of the working vehicles, in which power from an engine (not shown) is provided with a belt transmission mechanism having a tension clutch (not shown). ) Is transmitted to the input pulley (2) of the hydrostatic continuously variable transmission (1), and the power from the output shaft (3) of the hydrostatic continuously variable transmission (1) is transmitted to the first gear pair. From (9), it is transmitted to the mowing part (6) shown in FIG. 3 via the one-way clutch (5), the first transmission shaft (4) and the output pulley (7).

The power from the first gear pair (9) is transmitted to the second transmission shaft (11) via the second gear (10), and the second transmission shaft (11)
A first high-speed gear (12) is externally fitted so as to be relatively rotatable, and a shift gear (14) is externally slidably fitted with a spline structure. On the other hand, a second high-speed gear (16) and a low-speed gear (17) are fixed to the third transmission shaft (15),
The first high speed gear (12) is in mesh with the second high speed gear (16). Further, a medium speed gear 1 (8) is fixed to the third transmission shaft (15).

With the above structure, the shift gear (14) is slid to operate the first high-speed gear (12), the medium-speed gear (18), and the low-speed gear 1
By meshing with (7), the power can be shifted to three stages of high and medium speeds, and this power is transmitted to the third gear (19) that meshes with the medium speed gear (18).

A right psy gear (1R) and a left side gear (21L) are rotatably fitted on a support shaft (20) that supports the third gear (19), and input of left and right axles (22L) and (22R). Gears (23R) and (23L) are left and right side gears (21L) and (21
R) is always occluded. As a result, the right or left side gears (21R) and (21L) are slid into and out of engagement with the third gear (19) by the sliding operation so that the driving sprocket (24a) The input operation of power transmission is performed for the third gear (19).
Side clutches (25R) and (25L) are configured between the left and right side gears (21L) and (21R).

Next, a structure for braking one axle (22R) or (22L) will be described. As shown in FIG.
0), the right fourth gear (26R) and the left fourth gear (26L) are rotatably supported by bearings, and a pair of fifth gears (29) fixed to the fourth transmission shaft (27) is provided. It is in mesh with the fourth right gear (26R) and the fourth fourth gear (26L). A multi-disc 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 shifted to the third gear (1
9), the gear is engaged with the right fourth gear (26R) or the left fourth gear (26L), and the side brake (28) is engaged to operate the one axle (22R) or (2).
2L) can be braked. This is the pivot position.

Next, a structure for reversing one axle (22R) or (22L) will be described. As shown in FIG. 2, a sixth gear (37) engaging with the second high-speed gear (16) of the third transmission shaft (15).
Are externally rotatably fitted to the fourth transmission shaft (27), and a hydraulic clutch (30) is provided between the sixth gear (37) and the fourth transmission shaft (27). As a result, when the hydraulic clutch (30) is engaged 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 second high-speed gear (16) is transmitted to the axle (22R) or (22L) in a reverse rotation state and reduced to half. This is a super-spinning state.

Next, a structure for driving one axle (22R) or (22L) forward at a lower speed than the other will be described. As shown in FIG. 2, the first sprocket (13) is fixed to the third transmission shaft (15), and the second sprocket (27) is connected to the fourth transmission shaft (27).
A sprocket (38) is externally fitted to be relatively rotatable, and a transmission chain (40) is wound around the first and second sprockets (13) and (38) to form a low-speed transmission mechanism (43). A shift member (41) as a driven body is externally fitted to the fourth transmission shaft (27) by a spline structure so as to be slidable. Thereby, the shift member (41) is moved to the second position.
With the right or left side gear (21R) and (21L) engaged with the sprocket (38), the right or left fourth gear (26R),
(26L), the forward rotation power from the 34th shaft (15) is reduced by half and transmitted to the axle (22R) or (22L). The shift member (41) is provided with a spring (42) for urging the shift member (41) in a direction away from the second sprocket (38). That is, the second sprocket (38), the shift members (41), and (42) constitute a dog clutch (C) (corresponding to a mechanical clutch) provided in the low-speed transmission mechanism (43).

Next, a structure for supplying hydraulic oil to the hydraulic cylinders (31R) and (31L) for performing the sliding operation of the left and right side gears (21L) and (21R), the side brake (28), and the hydraulic clutch (30) will be described. As shown in FIG. 1, hydraulic oil from a pump (32) is supplied to hydraulic cylinders (31R) and (3R) for left and right side gears (21L) and (21R) via a first switching valve (33).
1L) and hydraulic cylinders (31R), (31
L) The oil passage (34) from the side is the side brake (28)
And a second switching valve (35) for the hydraulic clutch (30). Further, a variable relief valve (36) (corresponding to first switching means) for the side brake (28) and the hydraulic clutch (30) is connected to the oil passage (34).

Next, the operation structure of the first switching valve (33), the second switching valve (35), and the variable relief valve (36) will be described. As shown in FIG. 1, an operation lever (39) for turning operation operable to the left and right, a first switching valve (33), and a variable relief valve (36).
Operating arm (45) is mechanically linked via a wire (48) or the like. Further, a switching lever (44) (corresponding to a second switching means) for operating the second switching valve (35) and the shift member (41) in FIG. 2 is provided.

The state shown in FIG. 1 is a state in which the switching lever (44) is being operated to the pivot position, and the second switching valve (35) is in the position (35a) for supplying the hydraulic oil to the side brake (28). It is being operated. In this state, when the operating lever (39) is operated from the neutral position (N) to the first right turning position (R ₁ ) or the first left turning position (L ₁ ), the first switching valve (33)
Only the right or left side gear (21R) engaged with the third gear (19) via the right or left operating part (46R) or (46L) by the hydraulic cylinder (31R) or (31L) operated only ,
(21L) is separated from the third gear (19), and
Occludes gears (26R) and (26L).

In this case, the variable relief valve (36) is fully open,
Since both the side brake (28) and the hydraulic clutch (30) are in the off state, the right or left axle (22R),
(22L) transmission is cut off (side clutch (25L
(R) or (25L) cutting state), and the aircraft slowly turns right or left. The sequence valve (47) provided in the oil passage (34) is provided with a right or left side gear (21).
R) and (21L) are required to completely engage the right or left fourth gear (26R) and (26L) with the hydraulic cylinder (31).
R), (31L).

Then the operating lever (39) to the right or left first pivot position (R _1), (L ₁₎ right or left second turning position from (R _2),
(L ₂ ), the right or left side gear (21
R) and (21L) engage the right or left fourth gear (26R) and (26L), and the second switching valve (35) engages the side brake (28).
The wire (48) is pulled toward the operating lever (39) while the variable relief valve (36) is gradually moved from the fully open state to the closed side while the hydraulic oil supply position (35a) is being operated. Go. As a result, the side brake (28) starts to act, and the braking is gradually applied to the right or left axles (22R) and (22L), so that the aircraft turns right or left. Then, the right or left second turning position (R ₂ ) of the operating lever (39),
At (L ₂ ), the braking force of the side brake (28) becomes maximum.

Next, when the switching lever (44) is operated to the pivot turn position, the second switching valve (35) is switched to the supply position (35b) of the hydraulic oil to the hydraulic clutch (30). The state at the neutral position the operating lever (39) (N) right or left first turning position from (R _1), it is operated to (L _1), in the same manner as described above the right or left side clutch (25R), (25L ) Appears.

Then the operating lever (39) to the right or left first pivot position (R _1), (L ₁₎ right or left second turning position from (R _2),
(L ₂ ), the right or left side gear (21
R) and (21L) are engaged with the right or left fourth gear (26R) and (26L), and the second switching valve (35) is at the supply position (35b) of the hydraulic oil to the hydraulic clutch (30). In the operated state, the variable relief valve (36) is gradually operated from the fully opened state to the closed side as described above. As a result, the traveling device (24),
One of (24) is reversely driven to perform a pivot turn.

As shown in FIG. 1, a traction arm (49) (corresponding to traction means) that can swing around the axis (P ₁ ) is disposed with respect to the operation arm (45) for the variable relief valve (36). At the same time, a wire (50) is connected across the restraining arm (49) and the switching lever (44). With the above structure, when the switching lever (44) is operated to the pivot position or pivot position, the pulling action of the wire (50) causes the restraining arm (49) to be at the position shown by the solid line in FIG. Therefore, in this state, the operation arm (45) can be operated to the closed side, and the side brake (28) or the hydraulic clutch (30) is operated.

When the switching lever (44) is operated to the gentle turning position, the shift member (41) shown in FIG. 2 engages the second sprocket (38), and the wire (50) is returned to operate the spring (51). As a result, the restraining arm (49) is rotated downward in the drawing. As a result, the operation arm (45) for the variable relief valve (36) is forcibly returned to the fully open position and held, and regardless of the operation position of the second switching valve (35), the side brake (28) And both the hydraulic clutch (30) and the hydraulic clutch (30) are disengaged.

In this state, the operating lever (39) is operated to the right or left first turning position (R ₁ ) or (L ₁ ), and the right or left side gear (21) is turned.
When R) and (21L) are engaged with the right or left fourth gear (26R) and (26L), the right or left axles (22R) and (22L) are reduced to 1/2 and driven forward. . As a result, the aircraft slowly turns right or left. Also, in this state, even if the operation lever (39) is operated to the right or left second turning position (R ₂ ) or (L ₂ ) to pull the wire (48), the spring (52) for accommodation is still in place. The operation arm (45) is not operated to the closed side only by extending.

As shown in FIG. 2, a parking main brake (53) is provided at one end of the fourth transmission shaft (27). As shown in FIG. 1, a brake pedal (54), a main brake (53) and The left and right operation units (46R) and (46L) are mechanically linked. Thus, when the brake pedal (54) is depressed, the left and right side gears (21L) and (21R) are respectively operated by the left and right operation units (46R) and (46L).
L), (26R) and the main brake (5
3) is entered and the parking operation is performed.

In this case, the brake pedal (54) is also mechanically linked to the shift member (41) in FIG. 2, and when the brake pedal (54) is depressed, the shift member (41) is moved from the second sprocket (38). It is configured to be forcibly separated.

(Another embodiment)

As shown in FIG. 4, the second switching valve (35) (corresponding to the third switching means) is provided with an oil discharge position (35c), and the switching lever (44) (corresponding to the second switching means) is slowly turned. When operated to the position, the second switching valve (35) may be linked to be operated to the oil discharge position (35c). Thereby, at the time of gentle turning, regardless of the position of the operation arm (45) for the variable relief valve (36), the side brake (28) and the hydraulic clutch (30)
Is being cut off.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the structure shown in the attached drawings.

[Brief description of the drawings]

Drawings show an embodiment of a steering operation structure of a work vehicle according to the present invention, FIG. 1 is a view showing a linked state between a second switching valve and a variable relief valve and each part, and FIG. 2 is a longitudinal front view of a transmission case. Fig. 3 is a side view of the first half of the combine, and Fig. 4 is a view showing a linked state between the second switching valve and the variable relief valve and other parts in another embodiment. (24)… traveling device, (30)… hydraulic clutch, (35)
... third switching means, (36) ... first switching means, (38) transmitting body, (39) ... operating lever for turning, (41) ... driven body, (43) ... low-speed transmission mechanism , (44)... Second switching means, (49)... Restraint means, (C)... Mechanical clutch.

Claims (2)

(57) [Claims] 1. A steering operation structure for a working vehicle having a pair of right and left traveling devices (24), (24), wherein
[5] A steering operation structure for a work vehicle having the configuration described in [5]. [B] By contact of the power transmission element (38) and the power transmission element (41),
One of the traveling devices (24), (24) selected by operating the turning operation lever (39) is provided with a mechanical clutch (C) capable of transmitting forward rotation power at a lower speed than the other. A transmission mechanism (43) is provided. [B] One of the traveling devices (24), (24) selected by operating the operation lever (39) is provided with a hydraulic clutch (30) capable of transmitting reverse rotation power. [C] First switching means (36) capable of switching the operating state of the hydraulic clutch (30) to the hydraulic oil supply system for the operation of entering the hydraulic clutch (30) by operating the operation lever (39). Is provided. [D] Second switching means capable of selectively and quickly switching the low-speed transmission mechanism (43) between a transmission state and a non-transmission state by an operation system different from the operation system of the hydraulic clutch (30). (44). [E] When the second switching means (44) is switched to the transmission state side of the low-speed transmission mechanism (43), the first switching means (44) is operated in conjunction with this operation.
Checking means (49) is provided for forcibly switching and holding the switching means (36) to a state where the hydraulic clutch (30) is in a disengaged state. 2. A steering operation structure for a working vehicle comprising a pair of right and left traveling devices (24), (24), wherein
[5] A steering operation structure for a working vehicle having the configuration described in [6]. [F] Due to the contact between the transmitting body (38) and the driven body (41),
One of the traveling devices (24), (24) selected by operating the turning operation lever (39) is provided with a mechanical clutch (C) capable of transmitting forward rotation power at a lower speed than the other. A transmission mechanism (43) is provided. [G] One of the traveling devices (24), (24) selected by operating the operation lever (39) is provided with a hydraulic clutch (30) capable of transmitting reverse rotation power. [H] First switching means (36) capable of switching the operating state of the hydraulic clutch (30) to the operation for entering the hydraulic clutch (30) and to the hydraulic oil supply system by operating the operation lever (39). Is provided. [R] Second switching means (44) capable of switching the low-speed transmission mechanism (43) between a transmission state and a non-transmission state by an operation system different from the operation system of the hydraulic clutch (30). . (G) When the second switching means (44) is switched to the transmission state of the low-speed transmission mechanism (43), the third switching means (35) switches the hydraulic clutch (30) to the unload state in conjunction with the switching operation. ).