JP2574364Y2 - Travel transmission structure of work vehicle - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a work vehicle configured to transmit traveling power from an engine from a continuously variable transmission to a pair of left and right traveling devices via a pair of left and right hydraulic side clutches. Or a travel transmission structure of a working vehicle including a hydraulic side brake that applies a brake to a transmission device on the transmission cutoff side in addition to the above-described continuously variable transmission and the side clutch.

[0002]

2. Description of the Related Art Continuously variable transmissions used for traveling in a work vehicle as described above include a hydrostatic continuously variable transmission type, a belt type using split pulleys, and a tapered cone type. Such a continuously variable transmission can smoothly perform a shift operation from a neutral stop position where power is not transmitted to a highest speed position. By operating this continuously variable transmission to the neutral stop position, the machine stops. Can be done.

[0003]

As described above, the body can be stopped by operating the continuously variable transmission to the neutral stop position. However, the range of the neutral stop position where power transmission is not performed is limited. , This continuously variable transmission is very narrow. Therefore, even if the operator attempts to stop the body by operating the shift operation tool (shift lever, shift pedal, etc.) for the continuously variable transmission to the neutral stop position, the continuously variable transmission slightly deviates from the neutral stop position. May be in a state. This allows
Power may flow from the continuously variable transmission and the aircraft may move. In the present invention, in a traveling transmission structure of a working vehicle equipped with a hydraulic side clutch or a hydraulic side clutch and a side brake, the shift operation tool is operated to a neutral stop position by effectively utilizing the hydraulic circuit structure. It is an object of the present invention to simplify the structure of a traveling transmission structure that ensures that the aircraft stops in a case.

[0004]

The feature of the present invention resides in the following configuration of the traveling power transmission structure for a working vehicle as described above. In other words, the driving power is transmitted from the continuously variable transmission to the pair of left and right traveling devices via the pair of left and right side clutches, and the one selected by the operation of supplying and discharging hydraulic oil from the pump. The traveling power transmission structure of a working vehicle includes a hydraulic actuator that operates to cut off the transmission of a side clutch and a hydraulic side brake that brakes one of the traveling devices selected by supplying and discharging hydraulic oil from a pump. , And is configured as follows. The return oil from the hydraulic actuator that operates the side clutch is configured to be supplied to an oil supply path to the side brake, and the side clutch is selectively connected to a hydraulic oil supply / discharge path from the pump to the hydraulic actuator. A first switching valve for switching the supply and discharge of hydraulic oil to and from the hydraulic actuator so as to perform an on-off operation and an off-operation of both side clutches together; A first state in which the supply pressure oil is supplied / discharged to / from an oil passage to the side clutch side, and a pressure oil from the pump is prevented by preventing return oil from being discharged from the side clutch side, and A shift operation for providing a hydraulic operation means that can be switched to a second state to be supplied to a brake side, and for manually shifting the continuously variable transmission; Sakugu is provided a neutral sensor that detects that it is operated in the neutral stop position, based on the detection of the neutral stop position by the neutral sensor, configured to switch the hydraulic operation means to the second state.

[0005]

With the above construction, when the operator operates the shift operating device to the neutral stop position, the left and right traveling devices are braked by the side brakes, so that the continuously variable transmission for traveling is moved from the neutral stop position. Even if it is slightly off, the aircraft will stop reliably due to the braking action of the side brake. In the work vehicle provided with the side clutch and the side brake as described above, these are used for turning. That is, for example, when the transmission of the right side clutch is interrupted by the hydraulic actuator, the right traveling device is in a free-rotation state, and the body gradually turns to the right due to resistance from the ground. Then, when the right traveling device is braked by the side brake, the aircraft turns to the right. Therefore,
If a turning side brake is used for stopping when the shift operation tool is operated to the neutral stop position, it is not necessary to provide a dedicated brake for stopping, and the side brake can be used for stopping. Since a pump for supplying hydraulic oil to the side brake during turning is used as a hydraulic source for operating the side brake to the braking side during the above-described stop, there is no need to provide a dedicated hydraulic source for stopping.

[0006]

[Effect of the Invention] With the above configuration, when the shift operating device is operated to the neutral stop position, the aircraft is stopped without fail, so that the aircraft does not move unexpectedly and the shift operating device is neutrally stopped. It is possible to improve safety when operated to the position. In addition, since the turning side brake and its pump are also used for stopping when the shift operation tool is operated to the neutral stop position, parts can be shared and the structure can be simplified.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows a combine, which is an example of a work vehicle,
1 shows a structure inside a transmission case 8 of a traveling system, in which power from an engine (not shown) is transmitted via a belt transmission mechanism (not shown) having a tension clutch to a hydrostatic continuously variable transmission 1. And the power from the output shaft 3 of the continuously variable transmission 1 is transmitted to the reaper (not shown) via the first transmission shaft 4.

The 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 externally slidably fitted to the second transmission shaft 11 in a spline structure.
A high-speed gear 16 and a low-speed gear 17 are fixed to the transmission shaft 15. By sliding the shift gear 14 by the above-described structure and engaging the high-speed gear 16 or the low-speed gear 17, the power can be shifted in two stages of high and low.
This power is transmitted to the third gear 19 that meshes with the low-speed gear 17.

A right side gear 21R and a left side gear 21L are externally fitted to a support shaft 20 for supporting the third gear 19 so as to be relatively rotatable.
3 always meshes with the left and right side gears 21R and 21L. Thereby, the right or left side gear 21R, 21L
To the third gear 19 to be engaged and disengaged, thereby performing power transmission and transmission cutoff operations to the left and right crawler type traveling devices 24. The third gear 19 and the left and right side gears 21R and 21L are connected to each other. Side clutch 2 between
5R and 25L are configured.

Next, a description will be given of a structure for braking the traveling device 24 on the transmission cutoff side for turning. As shown in FIG. 2, the right fourth gear 26 </ b> R and the left fourth gear 26 </ b> L are supported on the support shaft 20 so as to be rotatable relative to each other.
A pair of fifth gears 29 fixed to the fourth transmission shaft 27 are engaged with the right fourth gear 26R and the left fourth 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
The right fourth gear 26R or the left fourth gear 26L
By operating the side brake 28 and engaging the side brake 28, the one traveling device 24 can be braked. This is the pivot position.

Next, a description will be given of a structure in which one of the traveling devices 24 is rotated forward at a lower speed than the other for turning.
As shown in FIG. 2, the first sprocket 1 is attached to the third transmission shaft 15.
3 is fixed, a second sprocket 38 is fitted around the fourth transmission shaft 27 so as to be relatively rotatable, and a transmission chain 40 is wound around the first and second sprockets 13 and 38. Then, the second sprocket 38 and the fourth transmission shaft 2
7, a gentle turning clutch 12 is provided. Accordingly, when the gentle turning clutch 12 is engaged with the right or left side gears 21R, 21L engaged with the right or left fourth gears 26R, 26L, the forward rotation power from the third transmission shaft 15 is reduced by 1 /. The speed is reduced to 2 and transmitted to one traveling device 24. This is a gentle turning state.

Next, a structure for supplying hydraulic oil to the hydraulic cylinders 31R, 31L (corresponding to hydraulic actuators) for performing the sliding operation of the left and right side gears 21R, 21L, the side brake 28, and the gentle turning clutch 12 will be described. As shown in FIG. 1, the operating oil from the pump 32 is supplied to the first switching valve 3.
3 and is supplied to hydraulic cylinders 31R and 31L for the left and right side gears 21R and 21L, and an oil passage 34 from the side surfaces of the hydraulic cylinders 31R and 31L is electromagnetically operated for the side brake 28 and the gentle turning clutch 12. It is connected to the second switching valve 35. Oil channel 3
4, a variable relief valve 36 for the side brake 28 and the gentle turning clutch 12 is connected.

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. 1, a switching lever 18 for the second switching valve 35 is provided in a control section of the fuselage, and based on the operating position of the switching lever 18, the control device 7 controls the second switching valve 35 to slowly release. Slow turning position 35 for supplying hydraulic oil to turning clutch 12
a, and the switching operation to the pivot position 35b for supplying hydraulic oil to the side brake 28 is performed. Further, the operation lever 39 provided on the control section of the aircraft, the first switching valve 33 and the variable relief valve 36 are connected to the first linkage mechanism 41 and the second linkage mechanism 4.
It is mechanically linked via 2.

The state shown in FIG. 1 is a state in which the switching lever 18 is operated to the pivot position, and a state in which the second switching valve 35 is operated to the pivot position 35b. In this state, the operation lever 39 is moved from the neutral position N to the first right position.
When operated to the turning position R1 or the left first turning position L1,
Only the first switching valve 33 is operated, and the right or left side gear 21R, 21L engaged with the third gear 19 is moved by the hydraulic cylinder 31R or 31L via the right or left operating section 46R, 46L to the third side. It is separated from the third gear 19 and meshes with the right or left fourth gear 26R, 26L.

In this case, since the variable relief valve 36 is in the fully open state and the side brake 28 is in the off state,
The transmission to the right or left traveling device 24 is cut off (the transmission of the side clutch 25R or 25L is cut off),
The aircraft slowly turns to the right or left. And
The sequence valve 47 provided in the oil passage 34 is configured such that the right or left side gear 21R, 21L is connected to the right or left fourth gear 2.
This is for securing the pressure necessary for completely engaging the 6R, 26L to the hydraulic cylinders 31R, 31L.

Next, the operating lever 39 is moved from the right or left first turning position R1, L1 to the right or left second turning position R2, L.
2, the right or left side gear 21R, 2
In a state where 1L engages the right or left fourth gear 26R, 26L and the second switching valve 35 is operated to the pivot position 35b, the variable relief valve 36 is gradually operated from the fully open state to the close side. Go. As a result, the side brake 28 starts to act and the right or left traveling device 24 is gradually braked, and the aircraft turns right or left. The braking force of the side brake 28 is maximized 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 right or left first turning position R1, L1, the transmission interrupted state of the right or left side clutch 25R, 25L appears as described above.

Next, the operating lever 39 is moved from the right or left first turning position R1, L1 to the right or left second turning position R2, L1.
2, the right or left side gear 21R, 2
1L engages the right or left fourth gears 26R, 26L and the second switching valve 35 is operated to the gentle turning position 35a, and the variable relief valve 36 is gradually closed from the fully opened state as described above. Going to be operated. As a result, the slow turning clutch 12 starts to operate, and the right or left traveling device 24 is gradually driven forward at a low speed, and the aircraft slowly turns right or left. Then, at the right or left second turning position R2, L2 of the operation lever 39, the gentle turning speed becomes maximum.

Next, a case where the continuously variable transmission 1 is operated to the neutral stop position will be described. As shown in FIG. 1, an electromagnetically operated valve 5 (corresponding to a hydraulic operating means) is provided between the pump 32 and the first switching valve 33. This solenoid operated valve 5
Is a working position 5a for supplying the hydraulic oil from the pump 32 to the first switching valve 33, and supplying the hydraulic oil from the pump 32 to the first switching valve 33 to shut off the oil passage of the first switching valve 33. And a stop position 5b for supplying the hydraulic oil from the pump 32 to the side brake 28, and is operated to the working position 5a by a spring. Then, in this work position 5a, gentle turning and pivot turning can be performed by the operation lever 39 as described above. Further, an electromagnetic on-off valve 6 (corresponding to a hydraulic operating means) is provided between the second switching valve 35 and the side brake 28, and is urged toward the communication side by a spring.

As shown in FIG. 1, a shift lever 43 (corresponding to a shift operation tool) for shifting the continuously variable transmission 1 is provided in a control section of the fuselage. The shift operation of the continuously variable transmission 1 is performed by operating from the neutral stop position N to the fastest forward position F and the fastest reverse position R. Then, the shift lever 43 is set to the neutral stop position N.
Contact-type neutral sensor 44 that detects that the device has been operated
Is provided. As shown in FIG.
Lever guide 45 is not linear, and the neutral stop position N
It is bent at. An adjusting bolt 48 capable of adjusting the left and right ranges of the neutral stop position N in FIG.
Are provided on the back side of the lever guide 45.

With the above structure, the operator can operate the shift lever 4
3 is operated to the neutral stop position N, and when the detection signal from the neutral sensor 44 is input to the control device 7, the electromagnetic operation valve 5 is operated to the stop position 5b by the control device 7, and the electromagnetic on-off valve 6 is closed. Operated to the position. Thereby, the first switching valve 3
The hydraulic oil is supplied to the first switching valve 33 in a state where the oil discharge passage 3 is shut off.
, The left and right hydraulic cylinders 31R, 31L
Is supplied to the left and right side gears 21R, 21R.
L meshes with the right and left fourth gears 26R, 26L. The hydraulic oil from the pump 32 is supplied to the side brake 28 from the solenoid operated valve 5 and the on-off valve 50 (a normally closed type that opens when the solenoid operated valve 5 reaches a set pressure). 6 is operated to the closed position, the side brake 28 is operated to the braking side, the left and right traveling devices 24 are braked, and the machine body stops.

[Alternative Embodiment] In the above-described embodiment, the switching lever 18 is configured to be able to select the gentle turning state and the pivot turning state. The present invention may be applied to this structure by being configured to be able to select a state (turning performed by driving one of the traveling devices 24 in the reverse direction). Next, the above structure will be described. As shown in FIG. 5, a gentle turning clutch 12 and the like for gentle turning are provided in the transmission case 8, and a hydraulic brake 49 is provided at one end of the fourth transmission shaft 27.

Next, a structure for driving one of the traveling devices 24 in the reverse direction will be described. As shown in FIG. 5, a sixth gear 37 meshing with the high-speed gear 16 of the third transmission shaft 15 is fitted around the fourth transmission shaft 27 so as to be relatively rotatable, and the sixth gear 3
A hydraulic multi-plate reverse rotation clutch 30 is provided between the transmission 7 and the fourth transmission shaft 27. Thereby, the right side gear 2
1R or the left side gear 21L is engaged with the right fourth gear 26R or the left fourth gear 26L, and the reverse clutch 3
When 0 is entered, the power from the high-speed gear 16 is transmitted to one traveling device 24 in the reverse rotation state and reduced to half. This is a super-spinning state.

A hydraulic circuit as shown in FIG. 4 is provided for the transmission case 8 shown in FIG. 5, and when the switching lever 18 is operated to the gentle turning position and the super pivot turning position, the controller 7 The two-way switching valve 35 is operated to a gentle turning position 35 a for supplying hydraulic oil to the gentle turning clutch 12 and a super pivot position 35 c for supplying hydraulic oil to the reverse rotation clutch 30. Thus, when the operation lever 39 is operated from the neutral position N to the right or left first turning position R1 or L1 in a state where the switching lever 18 is operated to the gentle turning position, the right or left side Clutch 25R, 2
A 5L transmission cutoff state appears. Then, when operated to the right or left second turning position R2, L2, one of the traveling devices 2
4 is driven forward at low speed to perform gentle turning.

Next, when the switching lever 18 is operated to the super pivot position, the second switching valve 35 is switched to the super pivot position 35c. In this state, when the operation lever 39 is operated from the neutral position N to the right or left first turning position R1, L1, similarly to the above, the right or left side clutch 25R, 2
A 5L transmission cutoff state appears.

Next, the operating lever 39 is moved from the right or left first turning position R1, L1 to the right or left second turning position R2, L.
2, the right or left side gear 21R, 2
1L is engaged with the right or left fourth gears 26R, 26L, and the second switching valve 35 is operated to the super pivot position 35c, and the variable relief valve 36 is gradually changed from the fully opened state as described above. It is operated to the closing side. As a result, the reverse rotation clutch 30 starts to operate, and the right or left traveling device 24 is gradually driven to reversely rotate, so that the aircraft makes a right or left turn. Then, at the right or left second turning position R2, L2 of the operation lever 39, the reverse rotation speed becomes maximum.

Next, the case where the continuously variable transmission 1 is operated to the neutral stop position will be described. As shown in FIG. 4, an electromagnetically operated valve 5 (corresponding to a hydraulic operating means) is provided between the pump 32 and the first switching valve 33. This solenoid operated valve 5
Is a working position 5a for supplying the hydraulic oil from the pump 32 to the first switching valve 33, and supplying the hydraulic oil from the pump 32 to the first switching valve 33 to shut off the oil passage of the first switching valve 33. , The stop position 5b for supplying the hydraulic oil from the pump 32 to the second switching valve 35 as well.
Being operated to the side.

A brake 49 is connected to an oil passage 51 branched from between the second switching valve 35 and the gentle turning clutch 12. In the oil passage 51, a supply position 52a for supplying hydraulic oil to the gentle turning clutch 12 to the brake 49 and operating the brake 49 on the braking side, and releasing the hydraulic oil from the brake 49 to release the brake 49 Oil discharge position 52 operated to the side
An electromagnetically operated valve 52 (corresponding to a hydraulic operating means) is provided which can be switched between two positions b and b. The electromagnetically operated valve 52 is urged toward the oil discharge position 52b by a spring. Further, between the second switching valve 35 and the variable relief valve 36, an electromagnetic on-off valve 56 (corresponding to hydraulic operating means) is provided.

With the above structure, the operator can operate the shift lever 4
3 is operated to the neutral stop position N, and when the detection signal from the neutral sensor 44 is input to the control device 7, the control device 7 operates the solenoid operated valve 5 to the stop position 5b, and the operation position of the switching lever 18 , The second switching valve 35 is operated to the gentle turning position 35a. Then, the electromagnetic on-off valve 52 is operated to the supply position 52a, and the electromagnetic on-off valve 56 is operated to the closed position.

As a result, the hydraulic oil is supplied to the first switching valve 33 in a state where the drainage passage of the first switching valve 33 is shut off, so that the hydraulic oil is supplied to the left and right hydraulic cylinders 31R and 31L. The left and right side gears 21R, 21L mesh with the right and left fourth gears 26R, 26L. And the pump 32
Is supplied to the gentle turning clutch 12 and the brake 49 via the electromagnetically operated valve 5, the check valve 53, the oil passage 34 and the second switching valve 35. Thereby, the gentle turning clutch 12
Is operated on the transmission side, and the brake 49 is operated on the braking side, so that the left and right traveling devices 24 are braked and the machine body stops.

Neutral sensor 4 shown in FIGS. 1 and 4
Instead of 4, it may be configured as shown in FIG. 6. That is, in the hydrostatic continuously variable transmission 1, the shift lever 4
The gear 54 is fixed to the transmission trunnion shaft 1a interlockingly connected to the gear 3 and a rotary potentiometer 55
(Corresponding to a neutral sensor) and has a structure in which a gear 55a fixed to the detection shaft is engaged with the gear 54. Thus, when the output from the potentiometer 55 is within the set range, it is determined that the shift lever 43 and the trunnion shaft 1a are at the neutral stop position N.

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 hydraulic circuit diagram of a side clutch, a hydraulic cylinder, a side brake, and the like.

FIG. 2 is a schematic longitudinal sectional front view showing a transmission structure in a transmission case.

FIG. 3 is a plan view of a lever guide of the shift lever.

FIG. 4 is a hydraulic circuit diagram of a side clutch, a hydraulic cylinder, a side brake and the like in a first alternative embodiment.

FIG. 5 is a schematic longitudinal sectional front view showing a transmission structure in a transmission case in the first alternative embodiment.

FIG. 6 is a side view showing the vicinity of a shift lever and a neutral sensor according to a second alternative embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Continuously variable transmission 5, 6, 52, 56 Hydraulic operating means 24 Traveling device 28 Side brake 25R, 25L Side clutch 31R, 31L Hydraulic actuator 32 Pump 43 Shift operating tool 44, 55 Neutral sensor 49 Brake N Neutral operating gear Stop position

Claims (1)

(57) [Scope of request for utility model registration] 1. A power transmission device for transmitting traveling power from a continuously variable transmission (1) to a pair of left and right traveling devices (24) via a pair of left and right side clutches (25R) and (25L). , One of the side clutches (25R) selected by the operation of supplying and discharging the hydraulic oil from the pump (32).
(25L) hydraulic actuator (3
1R) and (31L) and the operation of supplying / discharging the hydraulic oil from the pump (32), the selected traveling device (2
4) A traveling power transmission structure for a working vehicle including a hydraulic side brake (28) for applying a brake to the hydraulic clutches (31R) and (31L) for operating the side clutches (25R) and (25L). Return oil from the pump is supplied to an oil supply path to the side brake (28), and a pressure oil supply / discharge path from the pump (32) to the hydraulic actuators (31R) and (31L) is provided. The side clutches (25R) and (25L) are selectively turned on and off, and both side clutches (25R) are used.
R) and (25L) are provided with a first switching valve (33) for switching the supply and discharge of the pressure oil to and from the hydraulic actuators (31R) and (31L) so as to operate both of them. The pressure oil supplied from the pump (32) is supplied to the side clutch (25
R), the first state of supplying and discharging the oil passage to the (25L) side, and from the side clutch (25R), (25L) side.
The return oil is prevented from being discharged and the pressure from the pump (32) is reduced.
If the oil is on the side clutch (25R) or (25L) side
Shifting operation for providing a hydraulic operation means (5), (6) that can be switched to a second state to be supplied to a side brake (28) side, and for manually shifting the continuously variable transmission (1). Neutral sensors (44) and (55) are provided to detect that the tool (43) has been operated to the neutral stop position (N). Detection of the neutral stop position (N) by the neutral sensors (44) and (55) Based on the hydraulic operating means (5),
(6) A traveling power transmission structure of a working vehicle configured to switch the state to the second state.