JP2555276Y2 - Travel transmission structure of work vehicle - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling transmission structure of a working vehicle having a pair of left and right traveling devices such as a multi-wheel type or a crawler type with four wheels on one side.

[0002]

2. Description of the Related Art As an example of the above-mentioned work vehicle, there is a combine equipped with a pair of left and right traveling devices of a crawler type. In such a combine, one selected traveling device is rotated forward at a lower speed than the other. There is a configuration in which driving is performed to perform gentle turning, and one of the traveling devices is reversely driven to perform super turning. As shown in FIG. 3, for example, as shown in FIG. 3, when the left and right side gears 12 are engaged with the first transmission gear 7 to which the forward power for straight traveling is transmitted, the left and right side gears 12 The forward rotation power of the same speed is transmitted to the traveling device 4, and the aircraft advances straight.

When the control valves for the left and right hydraulic actuators are switched to the left turning side from this state, hydraulic oil is supplied to the left hydraulic actuator, and the left side gear 12 drives the left side gear 12 by the left hydraulic actuator. It is operated to move away from the transmission gear 7 to the left in the drawing. In this case, when the left side gear 12 reaches the neutral stop position just before the interlocking connection position with the second transmission gear 9, the hydraulic oil flows out of the left hydraulic actuator via the variable relief valve,
The left side gear 12 stops at this neutral stop position. As a result, the transmission to the left traveling device 4 is cut off, and the aircraft gradually turns to the left. When the variable relief valve is throttled, the left hydraulic actuator is further operated from the neutral stop position, and the left side gear 12 is interlocked with the second transmission gear 9. In this case, if the low-speed forward power is transmitted to the second transmission gear 9, the left traveling device 4 is driven at a lower speed than the right traveling device 4, and the airframe is caused by the speed difference between the left and right traveling devices 4. Turn slowly to the left. Then, if the reverse rotation power is transmitted to the second transmission gear 9, the left traveling device 4 is driven to rotate in the reverse direction, and the fuselage turns to the left in a left corner.

[0004]

In the above structure, one of the side gears is operated by a hydraulic actuator to a neutral stop position between the first transmission gear and the second transmission gear to transmit the power to one traveling device. The state of refusal appears and the direction of the aircraft is changed. Therefore, if the left and right side gears are simultaneously operated to the above-described neutral stop position, transmission to the left and right traveling devices can be cut off to temporarily stop the aircraft.
The present invention utilizes a pair of hydraulic actuators that slide the left and right side gears as they are, so that the left and right side gears can be operated to the neutral stop position and a paused state can be realized, and the suspension can be reliably performed. It is intended to be configured to be one.

[0005]

The feature of the present invention resides in the following configuration of the traveling power transmission structure for a working vehicle as described above. That is, an on-off valve is provided in an oil discharge passage from a control valve for both hydraulic actuators for the left and right side gears, and operating oil is supplied to both hydraulic actuators by operating the on-off valve on the closing side. At the same time, when the variable relief valve that stops both hydraulic actuators at the neutral stop position is operated to the closed side, the operation of the on-off valve to the closed side is prevented, and when the on-off valve is operated to the closed side, it is variable. A check means for preventing the operation of the relief valve to the closing side is provided.

[0006]

When the oil discharge passage 29 is closed by operating the on-off valve 30 to the closed side as shown in FIGS. 1 and 2, for example, as shown in FIG. 1 and FIG. At the same time, the left and right side gears 12 are operated to be separated from the first transmission gear 7 to the left and right by the left and right hydraulic actuators 33. In this case, if the variable relief valve 37 is in the open position, the left and right side gears 12 are in the first position.
When the neutral stop position between the transmission gear 7 and the second transmission gear 9 is reached, the hydraulic oil is released from the left and right hydraulic actuators 33 via the variable relief valve 37, and the left and right side gears 12 stop at this neutral stop position. As a result, the transmission to the left and right traveling devices 4 is cut off, and the aircraft temporarily stops.

As described above, when the left and right side gears 12 are operated to the neutral stop position by the left and right hydraulic actuators 33, it is a necessary condition that the variable relief valve 37 in FIG. 2 is in the open position. That is, if the variable relief valve 37 is operated to the closed side, the left and right hydraulic actuators 33
The hydraulic actuator 33 does not stop at the neutral stop position and the left and right side gears 12
The hydraulic actuator 33 operates until it reaches an interlocking connection position with the transmission gear 9. In this case, since low-speed forward power or reverse power is transmitted to the second transmission gear 9, at this time, the low-speed forward power or reverse power is transmitted to the left and right traveling devices 4 via the left and right side gears 12. Is transmitted, and the aircraft cannot move forward or backward to pause.

Therefore, when the above-described restraint means is provided, in a state where the variable relief valve 37 is operated to the closed side,
The on-off valve 30 shown in FIG.
This operation cannot be performed even if the user attempts to operate 2 at the neutral stop position. That is, in this state, when the on-off valve 30 is operated to the closing side to supply the hydraulic oil to the left and right hydraulic actuators 33,
This is because the left and right hydraulic actuators 33 operate until the left and right side gears 12 reach the interlocking connection position with the second transmission gear 9. Conversely, in a state in which the on-off valve 30 is operated to the closed side (a state in which the left and right side gears 12 are operated to the neutral stop position by the hydraulic actuator 33), even if the variable relief valve 37 is operated to the closed side. Cannot operate. That is, if the variable relief valve 37 is operated to the closed side in this state, the left and right hydraulic actuators 33 stopped at the neutral stop position are operated, and the left and right side gears 12 are interlocked with the second transmission gear 9. This is because the connection position is reached.

[0009]

As described above, the hydraulic actuator for the left and right side gears can be used as it is by incorporating a simple on-off valve into the hydraulic circuit having the existing structure of the hydraulic actuator, the control valve and the variable relief valve. Use
The left and right side gears can now be brought to the neutral stop position to display a temporary stop state. As a result, the structure for temporarily stopping the aircraft can be simply configured, which is advantageous in terms of manufacturing cost. Further, it is possible to prevent a situation in which the left and right side gears reach the second transmission gear and the body moves, thereby enabling a reliable temporary stop and improving the reliability and safety of the temporary stop of the work vehicle. did it.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 shows a structure in a transmission case 2 of a traveling system of a combine, which is one of the working vehicles, in which power from an engine (not shown) is connected to a belt transmission mechanism (not shown) having a tension clutch. Through this, it is transmitted to the input pulley 16 of the hydrostatic continuously variable transmission M. The power from the output shaft 1 of the hydrostatic continuously variable transmission M is supplied to the first transmission shaft 14.
Is transmitted to a cutting unit (not shown) via an output pulley 15.

Power from the output shaft 1 is transmitted to the second transmission shaft 21 via the first gear 10. This second transmission shaft 21
, A first high-speed gear 22 is fitted to the outside so as to be relatively rotatable, and the shift gear 3 is slidably mounted in a spline structure. A low-speed gear 25, a medium-speed gear 8, and a second high-speed gear 23 are attached to the third transmission shaft 24 in a spline structure, and the first and second high-speed gears 22, 23 are engaged. Thus, by sliding the shift gear 3 to engage the first high-speed gear 22, the medium-speed gear 8, and the low-speed gear 25, the power can be shifted to three stages of high, medium, and low. First transmission gear 7 to be engaged
Is transmitted to

Right and left side gears 12 are externally fitted to the support shaft 6 supporting the first transmission gear 7 so as to be relatively rotatable.
The input gears 18 of the left and right axles 5 are always engaged with the left and right side gears 12. Thereby, the first clutch F of the occlusal type is provided between the right or left side gear 12 and the first transmission gear 7.
C is formed, and the convex engagement portion 1 of the side gear 12 is formed.
By engaging the first gear 3 with the first transmission gear 7, the forward rotation power for straight traveling is transmitted to the left and right crawler-type traveling devices 4. The spring 19 urges the side gear 12 toward the first transmission gear 7.

A pair of second transmission gears 9 are externally fitted to the left and right sides of the support shaft 6, and a multi-plate friction type second clutch RC is provided between the second transmission gear 9 and the side gear 12. As shown in FIG. 4, the second clutch RC is configured by alternately arranging a friction plate 47 on the side gear 12 side and a pressure plate 48 on the second transmission gear 9 side, and an inner end 48 a of the pressure plate 48. Is extended to the vicinity of the outer surface of the side gear 12 to enhance the heat radiation effect. On the other hand, as shown in FIG.
The second gear 11 is fixed to both ends of the
8, the third transmission shaft 24 is slidable left and right. In this case, the low-speed gear 25 and the medium-speed gear 8
Is positioned by the sleeve 26, the position of the low-speed gear 25 or the medium-speed gear 8 does not change even if the third transmission shaft 24 is slid.

As shown in FIG. 3, a manually operated switching lever 32 is provided on a control section of the fuselage for sliding operation of the third transmission shaft 24. A pair of fourth transmission shafts 39 is supported on the left and right sides of the transmission case 2, and the third gear 27 and the fourth gear 28 are fixed to the fourth transmission shaft 39. Each of the transmission gears 9 is engaged.

According to the above structure, when the switching lever 32 is operated to the pivot position and the third transmission shaft 24 is slid leftward on the paper, the left and right second gears 11 of the third transmission shaft 24 are moved.
Are engaged with the left and right third gears 27. As a result, the power of the third transmission shaft 24 is reversed via the third gear 27, the fourth transmission shaft 39, and the fourth gear 28 in the left and right second transmission gears 9.
Is transmitted to Therefore, for example, when the left side gear 12 is separated from the first transmission gear 7 and the second clutch RC is pressed and engaged by the pressing portion 17 of the left side gear 12, the reverse rotation power of the left second transmission gear 9 is changed to the left. The signal is transmitted to the traveling device 4 and a left turn can be performed.

Next, when the switching lever 32 is operated to the gentle turning position and the third transmission shaft 24 is operated to slide rightward on the paper,
The left and right second gears 11 of the third transmission shaft 24 directly mesh with the left and right second transmission gears 9. As a result, forward rotation power that is lower in speed than the forward rotation power transmitted from the third transmission shaft 24 to the first transmission gear 7 is transmitted from the third transmission shaft 24 to the second transmission gear 9. Therefore, for example, when the left side gear 12 is separated from the first transmission gear 7 and the second clutch RC is pressed and operated by the pressing portion 17 of the left side gear 12, the left traveling device 4 is operated at a lower speed than the right traveling device 4. The main body is driven to rotate forward, and the body slowly turns left due to the speed difference between the left and right traveling devices 4.

Next, the sliding operation structure of the left and right side gears 12 will be described. As shown in FIGS. 2 and 3, an operation arm 20 for sliding the left and right side gears 12 is provided.
And a hydraulic cylinder 33 (corresponding to a hydraulic actuator) for swinging the hydraulic cylinder. In this case, the hydraulic cylinder 33 is provided with a spring (not shown) for urging the hydraulic cylinder 33 toward the contraction side, and hydraulic oil from a pump 34 is supplied to an electromagnetically operated control valve 35 for the hydraulic cylinder 33. I have. When the hydraulic cylinder 33 is extended until the side gear 12 separates from the first transmission gear 7 (the first clutch FC is disengaged) and moves to a position where the second clutch RC is not pressed and operated, the hydraulic cylinder 33 starts operating. A drain oil passage 36 for draining oil and stopping the hydraulic cylinder 33 at that position is provided, and a variable relief valve 37 is provided in the drain oil passage 36.

Next, the control valve 35 and the variable relief valve 37
The operation of is described. The state shown in FIG. 2 and FIG.
The left and right side gears 12 are in a straight running state in which they engage with the first transmission gear 7. When, for example, the operation lever 40 is operated to the left first turning position L1 from this state, only the control valve 35 is switched, the hydraulic oil is supplied to the left hydraulic cylinder 33, and the left side gear 12 is moved leftward on the paper. Slide first
Moves away from the transmission gear 7 (the disengagement state of the first clutch FC). In this case, since the variable relief valve 37 is in the fully open state, the drain oil passage 36 opens at the neutral stop position before the left side gear 12 presses the second clutch RC, and the hydraulic oil flows out of the variable relief valve 37, The left side gear 12 stops at this neutral stop position. This is the left traveling device 4
The aircraft is gently turning to the left.

When the operating lever 40 is operated to the left second turning position L2, the variable relief valve 37 is throttled, the hydraulic cylinder 33 is extended from the neutral stop position, and the left second clutch RC is completely released. Is operated. In this case, as shown in FIG. 3, the switching lever 32 is operated to the super pivot position, and the left and right second gears 11 of the third transmission shaft 24 are moved.
Is engaged with the third gear 27, the traveling device 4 on the left is driven to rotate in the reverse direction, so that the super-revolution can be performed. When the operating lever 40 is operated between the first turning position L1 and the second turning position L2 on the left, the hydraulic oil is removed from the hydraulic cylinder 33 from the above-described state, and the pressing force on the second clutch RC is reduced. .
As a result, the second clutch RC slips and the left traveling device 4
The reverse rotation speed can be changed.

Conversely, if the switching lever 32 is operated to the gentle turning position and the left and right second gears 11 of the third transmission shaft 24 are directly engaged with the second transmission gear 9, the operation lever 40 is moved to the left. When operated to the second turning position L2, the left traveling device 4 is forwardly driven at a low speed to perform a gentle turning. When the operating lever 40 is positioned between the left first and second turning positions L1 and L2, the second clutch RC slips and the low-speed forward rotation speed of the left traveling device 4 can be changed as described above. . The above operation is similarly performed at the right first turning position R1 and the second turning position R2.

Next, a structure for temporarily stopping the machine body by operating and holding the left and right side gears 12 at the neutral stop position will be described. As shown in FIG. 2 and FIG. 1, it is possible to switch between a closed position that provides sufficient resistance to the discharge of hydraulic oil (the opening degree of the throttle at this position is adjustable) and a fully opened position.
An on-off valve 30 urged toward the fully open position by a spring is provided in an oil discharge passage 29 from a control valve 35 for both hydraulic cylinders 33. An operation arm 31 is provided around the horizontal axis P1 of the machine body so as to be vertically swingable and capable of operating the on-off valve 30 to a closed position. The operation pedal 41 and the operation arm 31 are connected by a link rod 42. , Operation pedal 4
A spring 43 is provided for urging the valve 1 toward the return side (toward the fully open position of the on-off valve 30).

With the above structure, when the operation lever 40 is operated to the neutral position N (the control valve 35 is operated to the neutral position), the operation pedal 41 is depressed to close the open / close valve 30. When it is operated to the position, the hydraulic oil from the pump 34 is supplied to the left and right hydraulic cylinders 33 at the same time, and the left and right hydraulic cylinders 33 separate the left and right side gears 12 in FIG.
In this case, since the operation lever 40 is operated to the neutral position N and the variable relief valve 37 is fully opened, the drain oil passage 36 opens at the neutral stop position before the left and right side gears 12 press the second clutch RC. The hydraulic oil escapes from the variable relief valve 37, and the left and right side gears 12 stop at this neutral stop position. As a result, the transmission to the left and right traveling devices 4 is cut off, and the aircraft temporarily stops.

Next, a description will be given of the structure of the suspension operation by the operation pedal 41 and the mutual restraint of the operation lever 40. As shown in FIG. 1, the operation unit 3 of the variable relief valve 37
7a is urged to the fully open side by a spring (not shown) provided therein, and an operation arm 44 capable of operating the operation portion 37a to the closed side is swingably supported around the horizontal axis P2. I have. The operation lever 40 and the operation arm 44 are interlocked and connected via a wire 45.
Is operated from the right and left first turning positions R1 and L1 to the right and left second turning positions R2 and L2, the wire 45 is pulled toward the operation lever 40 and the variable relief valve 37 is operated.
Is operated to the closed side.

As shown in FIG. 1, a traction rod 46 (corresponding to traction means) is connected to the operation arm 44 by a pin.
A long hole 46 a is provided at the tip of the restraining rod 46.
Then, a pin 31a fixed to the tip of the operation arm 31
Is inserted into the elongated hole 46a of the restraining rod 46.

With the above structure, the operation lever 40 is operated to the neutral position N as shown in FIG. 1 (the control valve 35 in FIG. 2 is operated to the neutral position, and the variable relief valve 37 is operated to the fully open position). Only when the operation pedal 41 is pressed). In this state,
When the on-off valve 30 is operated to the closed position by the operation pedal 41, the hydraulic oil from the pump 34 shown in FIG. 2 is reliably and simultaneously supplied to the left and right hydraulic cylinders 33 (the control valve 35 shown in FIG. 2).
Are in the neutral position), the left and right side gears 12 are in the first position.
The operation is surely separated from the transmission gear 7 to the left and right. And
When the left and right side gears 12 reach the neutral stop position, the hydraulic oil is reliably discharged from the left and right hydraulic cylinders 33 (since the variable relief valve 37 in FIG. 2 is in the fully open position), and the left and right side gears 12 are moved to the neutral stop position. It stops at
The aircraft will pause for sure.

Conversely, when the operating lever 40 is operated to the right or left second turning position R2, L2, the wire 45
Is pulled to the operation lever 40 side, and the operation arm 44 is
Is operated clockwise from the state shown by the solid line in FIG. 1 to operate the variable relief valve 37 to the closed position. In this state, the restraining rod 46 is lifted upward in the drawing, and the pin 31a of the operation arm 31 reaches the lower end of the long hole 46a. Therefore, in this state, even if an attempt is made to operate the operation pedal 41, the operation cannot be performed.

When the operation pedal 41 is strongly depressed from the above-described state, the on-off valve 30 is operated to the closed position, and at the same time, the operation arm 44 is moved by the restraining rod 46 as shown in FIG.
The operation is returned from the state shown by the two-dot chain line to the state shown by the solid line. As a result, the variable relief valve 37 is returned to the fully open position, the wire 45 is pulled toward the operation arm 44, and the operation lever 40 is returned to the neutral position N.

Next, when the operation pedal 41 is depressed, the operation arm 31 is in a state shown by a two-dot chain line in FIG. 1, and the pin 31 a of the operation arm 31 is attached to the lower end of the long hole 46 a of the restraining rod 46. Has reached. Therefore, in this state, even if the operation lever 40 at the neutral position N is operated to the right or left second turning position R2, L2, the operation arm 44 cannot swing from the state shown by the solid line in FIG. Therefore, the operation lever 40 cannot be operated to the right or left second turning position R2, L2.

When the operating lever 40 is operated to the right or left second turning position R2 or L2 from the above state,
The operation arm 44 swings clockwise from the state indicated by the solid line, and the operation pedal 41 is returned by the restraint rod 46, and the on-off valve 30 returns to the fully open position.

[Another Embodiment] In the embodiment shown in FIG. 3, a state in which low-speed forward rotation power is transmitted to the second transmission gear 9 (slow turning state) and a state in which reverse rotation power is transmitted (super turning point) State), and is configured to be freely operable to be switched between two states. This is a type in which only low-speed forward power is transmitted to the second transmission gear 9 or only reverse rotation power is transmitted to the second transmission gear 9. It may be configured to be a model that performs In the embodiment of FIG. 3, the first clutch FC is configured as an occlusal type and the second clutch RC is configured as a friction type.
C is configured as a friction type, the second clutch RC is configured as an occlusal type, both the first and second clutches FC, RC are configured as an occlusal type, or both the first and second clutches FC, RC are configured. May be configured as a friction type.

In the claims of the utility model registration, reference numerals are written for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings by the entry.

[Brief description of the drawings]

FIG. 1 is a view showing a linked state of an operation lever, an operation pedal, an on-off valve, and a variable relief valve.

FIG. 2 is a hydraulic circuit diagram of a hydraulic cylinder for a side gear, a control valve, an on-off valve, a variable relief valve, and the like.

FIG. 3 is a schematic diagram showing a transmission structure in a transmission case.

FIG. 4 is a longitudinal sectional front view of the vicinity of a friction plate and a pressure plate of a second clutch.

[Explanation of symbols]

 4 Traveling Device 7 1st Transmission Gear 9 2nd Transmission Gear 12 Side Gear 29 Drainage Path 30 Open / Close Valve 33 Hydraulic Actuator 35 Control Valve 37 Variable Relief Valve 46 Checking Means

Claims (1)

(57) [Scope of request for utility model registration] 1. A pair of right and left side gears (12) for transmitting power to each of the left and right traveling devices (4). And a second transmission gear (9) to which low-speed forward or reverse rotation power is transmitted.
And each of the left and right side gears (12) is interlockedly connected to the first transmission gear (7);
A pair of hydraulic actuators (33) that are slidable independently over an interlocking connection position with the transmission gear (9) are provided.
By selectively supplying hydraulic oil to 3), one side gear (12) can be slid from an interlocking connection position with the first transmission gear (7) to an interlocking connection position with the second transmission gear (9). In the state where hydraulic oil is being supplied from the control valve (35) to the hydraulic actuator (33), the hydraulic oil is removed from the hydraulic actuator (33) and the first and second side gears (12) 2 is a traveling transmission structure of a working vehicle including a variable relief valve (37) capable of holding the hydraulic actuator (33) so as to be located at a neutral stop position between the two transmission gears (7) and (9). An open / close valve (30) is provided in a drain passage (29) from the control valve (35) to both hydraulic actuators (33), and the open / close valve (30) is operated by closing the same. Oil is supplied to both hydraulic actuators (33), and when the variable relief valve (37) is operated to the closed side, the operation of the open / close valve (30) to the closed side is prevented. And a traveling transmission structure for a working vehicle including a check means (46) for preventing the operation of the variable relief valve (37) to the closed side when the open / close valve (30) is operated to the closed side.