JP2567509B2 - Work vehicle steering operation structure - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a steering operation structure for a work vehicle provided with a pair of right and left crawler type or multi-wheel type traveling devices.

[Conventional technology]

An example of the work vehicle as described above is a combine equipped with a crawler type traveling device. In such a combine, for example, as disclosed in Japanese Utility Model Laid-Open No. 2-68272, a hydraulically operated side brake for braking one of the selected traveling devices ((28) in the above publication).
And a hydraulic clutch ((30) in the above publication) capable of transmitting reverse rotation power to one of the selected traveling devices.

As a result, it is possible to make a turning turn by braking one of the traveling devices with the side brakes, and by driving the one traveling device in the reverse direction with a hydraulic clutch, it is possible to make a turning turn with a smaller radius. You can turn.

[Problems to be Solved by the Invention]

The surface condition of the paddy field where the combine runs varies greatly depending on the hardness of the mud and the amount of water. Therefore, in an ultra-wetland where there is a lot of water and the mud on the surface is very soft, if one of the traveling devices is driven in reverse to make a super-spinning turn, the crawler digs the mud on the surface and the fuselage sinks below. Such a situation occurs.

Conversely, when braking is applied to one of the traveling devices in a paddy field or pavement where the amount of water is small and the mud on the surface is very hard, the traveling device on the braking side may slip and it may not be possible to turn properly.

It is an object of the present invention to enable successful turning and steering operations regardless of the state of the work site where the work vehicle travels.

[Means for solving the problem]

A feature of the present 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 hydraulically operated side brake for braking the selected one of the traveling devices.

[B] A hydraulic clutch capable of transmitting reverse rotation power to a selected one of the traveling operations is provided.

[C] A common boost control mechanism is provided for the hydraulic oil supply system for entering and operating the side brake and the hydraulic clutch.

[D] The operation lever and the boost adjustment are adjusted so that the pressure for entering and operating the side brake or the hydraulic clutch is increased by the boost adjusting mechanism corresponding to the operation position of the operation lever for manual operation. Coordinate with the mechanism.

[E] A switching unit is provided that can switch between a first state in which the side brake is operable and the hydraulic clutch is inoperative and a second state in which the side brake is inoperative and the hydraulic clutch is operable.

[F] The increase amount of the braking torque of the side brake with respect to the unit operation amount of the operation lever in the first state of the switching means, and the hydraulic clutch with respect to the unit operation amount of the operation lever in the second state of the switching means. The braking characteristic of the side brake and the transmission characteristic of the hydraulic clutch are set so that the increase amount of the transmission torque is larger than the increase amount of the braking torque.

[Work]

With the configuration described above, it is sufficient to switch to the first state in which the side brake can be operated in a soft work area. In this way, it is possible to prevent one of the traveling devices from rotating in the reverse direction, and to avoid slipping into the airframe to some extent.

In a soft work site, the resistance applied to the traveling device from the ground is very large, and even if one of the traveling devices is intended to be slightly braked, the traveling device may stop and make a small turn. In this case, by setting the area and number of friction plates in the side brakes, the size and number of pistons for pressing the friction plates, the condition of the oil passages in the side brakes, etc. Even if the boosting operation is performed, the braking torque of the side brake does not increase so much. As a result, the braking torque of the side brakes is finely adjusted by the operating lever, and one of the traveling devices is changed from a state in which it rotates while being braked to a state in which it is almost completely stopped, so that the turning radius can be finely adjusted. You can do it.

On the contrary, in a hard work place, the hydraulic clutch for reverse rotation is switched to the second state in which it can be operated. As a result, if the traveling device is driven in the reverse direction even in a slippery and hard working condition, slippage of the traveling device is reduced and accurate turning can be performed.

In this case, the same as in the case of the side brake described above, depending on the area and number of friction plates in the reverse hydraulic clutch, the size and number of pistons for pressing the friction plates, and the state of the oil passage in the hydraulic clutch. When the boosting operation is performed by the operating lever, the transmission torque of the hydraulic clutch rapidly increases, contrary to the case of the side brake. Therefore, when the operation lever is started to be operated, the hydraulic clutch is engaged relatively quickly, and the turning is performed without delay.

〔The invention's effect〕

As described above, it becomes possible to select the state in which the side brake can be operated or the state in which the hydraulic clutch for reverse rotation can be operated according to the state of the work site. Etc. could be reduced.

When turning using the side brakes, it is possible to easily adjust the turning radius by changing the braking condition of the side brakes, and it is possible to drive one of the traveling devices in reverse without delay. It was possible to improve the turning and steering performance.

〔Example〕

 Embodiments of the present invention will be described below 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)
The shift gear (14) is slidably fitted on the outer side by a spline structure. On the other hand, the low speed gear (17) and the medium speed gear (18) are fixed to the third transmission shaft (15), and the shift gear (12) is slidably fitted in the spline structure (the first gear). The state of Fig. 2 shows the shift gear (12).
Is engaged with the eighth gear (41) described later).

With the above structure, the shift gear (14) is slid to operate the shift gear (12), the medium speed gear (18), and the low speed gear (17).
The power can be shifted to three stages of high, medium and low by engaging with the gear. This power is transmitted to the third gear (19) which meshes with the medium speed gear (18).

A right side gear (21R) and a left side gear (21L) are fitted around a support shaft (20) supporting the third gear (19) so as to be relatively rotatable, and inputs of left and right axles (22L) and (22R) are provided. 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), (21L) are slidingly operated with respect to the third gear (19) to engage and separate from each other, and the drive sprocket (24a) of the crawler type traveling device (24) shown in FIG. ) Is turned on and off for power transmission, and the third gear (19)
Side clutches (25R) and (25L) are configured between the left and right side gears (21L) and (21R).

Next, the structure for braking one axle (22R) or (22L) will be described. As shown in FIG.
The right fourth gear (26R) and the left fourth gear (26L) are rotatably supported by the bearing 0), and the pair of fifth gears (29) fixed to the fourth transmission shaft (27) It meshes with the 4th right gear (26R) and 4th left gear (26L). 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 shifted to the third gear (1
9) Separate the gear from the right fourth gear (26R) or left fourth gear (26R).
L) and engage the side brake (28) to operate one axle (22R) or (22L)
Can be braked. Then, this is a turning state.

Next, a structure for reversing one axle (22R) or (22L) will be described. As shown in FIG. 2, the sixth gear (3
7) is fitted onto the fourth transmission shaft (27) so as to be relatively rotatable, and a hydraulic clutch (30) is provided between the sixth gear (37) and the fourth transmission shaft (27). As a result, the shift gear (12) is slid to the left side of the drawing, and the sixth gear (3
After directly engaging with 7), the right side gear (21R) or the left side gear (21L) is engaged with the right fourth gear (26R) or the left fourth gear (26L) as described above, and the hydraulic clutch ( When the power switch (30) is turned on and off, the power from the shift gear (12) is reversely rotated and is decelerated to 1/2 and transmitted to the axle (22R) or (22L). And this is a super-trust turning state.

In the above structure, the shift gear (12) is replaced by the sixth gear (37).
When directly engaged with, the shift gear (12) is separated from the shift gear (14). That is, in a state where the hydraulic clutch (30) can perform super-spinning turning, the shift gear (14) cannot engage with the shift gear (12) for high-speed transmission.

Next, a structure in which one axle (22R) or (22L) is driven to rotate forward at a lower speed than the other will be described. As shown in FIG. 2, the seventh gear (40) and the eighth gear (41) are fixed to the fifth transmission shaft (38), and the seventh gear (40) meshes with the sixth gear (37). are doing. This allows the shift gear (12)
After engaging the 8th gear (41) with the right side gear (21R) or the left side gear (21L) to the right fourth gear (26R) or the left fourth gear (26L) as described above. When the hydraulic clutch (30) is engaged and operated in the engaged state, the power from the shift gear (12) is in the normal rotation state and is decelerated to 1/2 and transmitted to the axle (22R) or (22L). . And, this is a gentle turning state.

Next, a hydraulic oil supply structure for the hydraulic clutches (31R), (31L), the side brakes (28) and the hydraulic clutch (30) for sliding the left and right side gears (21L), (21R) will be described. As shown in FIG. 1, the hydraulic oil from the pump (32) passes through the first switching valve (33) to the hydraulic cylinders (31R), (31R) for the left and right side gears (21L), (21R).
L) and hydraulic clutches (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 a boost control mechanism) 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) that can be operated left and right, a first switching valve (33) and a variable relief valve (36) are mechanically linked. Further, a switching lever (13) (corresponding to switching means) for operating the second switching valve (35) and the shift gear (12) of FIG. 2 is provided.

The state shown in FIG. 1 is a state in which the switching lever (13) is operated to the pivot turning position, the shift gear (12) is engaged with the eighth gear (41), and the second switching valve (35) is This is a state in which the hydraulic oil is supplied to the side brake (28) at the supply position (35a) (corresponding to the first state). In this state, when the operation 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 ),
Only the first switching valve (33) is operated to operate the hydraulic cylinder (31
(R) or (31L) to operate the right or left operation unit (46R), (46
L), the right or left side gear (21R), (21L), which has been in mesh with the third gear (19), is separated from the third gear (19), and the right or left fourth gear (26R), (26L).

In this case, the variable relief valve (36) is fully open,
Since both the side brake (28) and hydraulic clutch (30) are in the disengaged state, the right or left axle (22R),
(22L) transmission is cut off (side clutch (25L
(R) or (25L) turning state) and the aircraft gently turns to the right or left. Further, the sequence valve (47) provided in the oil passage (34) is connected to the 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) are engaged with the right or left fourth gear (26R) and (26L), and the second switching valve (35) is the side brake (28).
The variable relief valve (36) is gradually operated from the fully opened state to the closed side while being operated to the hydraulic oil supply position (35a). As a result, the side brake (28) starts to act and the right or left axle (22R), (22L) is gradually braked, and the aircraft turns right or left. Then, right or left second pivoting position of the operating lever (39) (R _2), the braking force of the parking brake (28) is maximized in (L _2).

In this case, by setting the area and number of friction plates in the side brake (28), the size and number of pistons for pressing the friction plates, the state of the oil passage in the side brake (28), etc.
Based on the operation of the operating lever (39), the variable relief valve (3
Even if the pressure is increased by 6), the side brake (2
The braking torque of 8) does not rise so much. As a result, the braking torque of the side brake (28) is finely adjusted by the operating lever (39), and one of the operating devices (24) and (24) is substantially completely stopped from the state in which it rotates while being braked. The turning radius can be finely adjusted by changing the state.

Next, when the switching lever (13) is operated to the super-solid turning position, the shift gear (12) is slid so as to directly mesh with the sixth gear (37), and the second switching valve (35) is hydraulically operated. It is switched to the hydraulic oil supply position (35b) to the clutch (30) (corresponding to the second state). 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.

Next, move the operating lever (39) to the right or left first turning position (R ₁ ), (L 1) to the right or left second turning position (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 hydraulic oil supply position (35b) 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.

In this case, by setting the area and the number of friction plates in the reverse hydraulic clutch (30), the size and number of pistons for pressing the friction plates, the condition of the oil passage in the hydraulic clutch (30), etc. As in the case of the side brake (28), when the operating lever (39) is used to increase the pressure, the transmission torque of the hydraulic clutch (30) will rise rapidly, contrary to the case of the side brake (28). ing. Therefore, when the operation lever (39) is started to operate, the hydraulic clutch (30) is engaged relatively quickly, and the turning is performed without delay.

Next, when the switching lever (13) is operated to the gentle turning position,
The shift gear (12) is slid so as to engage with the eighth gear (41), and the second switching valve (35) is switched to the hydraulic oil supply position (35b) to the hydraulic clutch (30). . When the operating lever (39) is operated from the neutral position (N) to the right or left first turning position (R ₁ ) or (L ₁ ) in this state,
Same as above, right or left side clutch (25R), (25L)
The cut state of 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 hydraulic oil supply position (35b) 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. This allows the right or left axle (22
R) and (22L) are decelerated to 1/2 and are driven in the normal direction, and the aircraft slowly turns to the right or left.

As shown in FIG. 4, an oblique wide notch (42a) along the circumferential direction is provided in the upper part of the ring member (42) supporting the bearing (16) for the first transmission shaft (4). . As a result, the lubricating oil flowing along the inner wall surface of the mission case (8) is sent from the notch (42a) to the one-way clutch (5) through the oil passage (4a) in the first transmission shaft (4). Is configured.

Instead of the structure shown in FIG. 4, the ring member (42) may be omitted as shown in FIG. 5, and the notch (8a) may be provided on the inner wall surface of the mission case (8).

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

[Brief description of drawings]

1 shows an embodiment of a steering operation structure for a work vehicle according to the present invention, FIG. 1 is a view showing a state in which an operating lever, a switching lever and respective parts are linked, and FIG. 2 is a schematic front view of a mission case,
FIG. 3 is a side view of the front half of the combine, FIG. 4 is a vertical sectional front view of the vicinity of the first transmission shaft to the cutting unit, and FIG. 5 is a vertical sectional front view showing another structure of FIG. (13) …… Switching means, (24) …… Traveling device, (27) ……
Side brake, (30) …… Oil passage clutch, (36) ……
Step-up adjustment mechanism, (39) …… Operating lever.

Claims (1)

(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]. [A] A hydraulically operated side brake (28) for braking the selected one of the traveling devices (24), (24).
Is provided. [B] A hydraulic clutch (30) capable of transmitting reverse rotation power is provided to a selected one of the traveling devices (24) and (24). [C] The side brake (28) and hydraulic clutch (3
A common boost control mechanism (36) is provided for the hydraulic oil supply system for the entry operation to the 0). [D] The pressure for entering the side brake (28) or the hydraulic clutch (30) is increased by the boost control mechanism (36) corresponding to the operation position of the operation lever (39) for manual operation. The operation lever (39) and the boost adjusting mechanism (36) are linked so that the operation lever (39) is operated. [E] A first state in which the side brake (28) is operable and the hydraulic clutch (30) is inoperative, and a second state in which the side brake (28) is inoperative and the hydraulic clutch (30) is operable. And a switching means (13) capable of switching to. [F] The amount of increase in the braking torque of the side brake (28) with respect to the unit operation amount of the operation lever (39) in the first state of the switching means (13) and the second state of the switching means (13). In the increase amount of the transmission torque of the hydraulic clutch (30) with respect to the unit operation amount of the operation lever (39), the side brake (so that the increase amount of the transmission torque is greater than the increase amount of the braking torque). 28) Set braking characteristics and hydraulic clutch (30) transmission characteristics.