JP3492529B2 - Work vehicle turning control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to turning of a work vehicle provided with a pair of left and right traveling devices and a turning operation means for switching the turning operation state of each of the running devices based on a turning command operation of a turning operation tool. Regarding the control device.

[0002]

2. Description of the Related Art In a turning control apparatus for a work vehicle having the above structure, conventionally, as shown in, for example, Japanese Patent Application Laid-Open No. 7-47973, the turning operation means operates any one of the following a, b, and c. Some were configured so that they could be switched to the mode. a. As the amount of turning operation from the straight-ahead command position in the turning operation tool to the left or right increases, the steering clutch is disengaged to cause the traveling device located on the turning side to be in a free-idling state. State, an operation mode in which the traveling device located on the turning side is sequentially switched to a slowly turning state in which the traveling device is driven at a lower speed than the other traveling device. b. As the turning operation amount increases, the steering clutch is disengaged and the running device located on the turning side is in a non-idling turning state in which the running device located on the turning side is in a free idle state, and the running device located on the turning side is the other running device. An operating mode in which the vehicle is sequentially switched to a slow turning state in which it is driven at a lower speed than that, and a free turning state in which the traveling device located on the turning side is in a free idle state and is braked. c. An operation mode in which as the turning operation amount increases, the non-driving turning state, the landing turning state, and the super landing turning state in which the left and right traveling devices are driven in opposite directions are sequentially switched. The operation mode is switched according to the magnitude of the operation force applied to the turning operation tool, or is switched in advance by a dedicated switching lever prior to the turning operation.

[0003]

In the above-mentioned conventional structure, one of the above operation modes can be selected according to the situation of the work place to be traveled, such as the difference in running resistance. .

However, in the above-mentioned conventional configuration, for example, in the configuration in which the operation mode is switched according to the magnitude of the operation force applied to the turning operation tool, the operation force corresponding to the operation mode desired by the operator is accurately applied to the turning operation tool. It may be a difficult task for an unskilled operator to assign the above. Further, in the configuration in which the operation mode is switched in advance by the dedicated switching lever prior to the turning operation, it is necessary to perform the switching operation of the switching lever separately from the turning operation for the turning operation tool, and the operation is cumbersome accordingly. There is also a risk of forgetting to switch the switching lever.

That is, according to the above-mentioned conventional structure, in the turning operation, when the turning operation tool is operated, there is a possibility that the turning operation is performed in a state where the operation mode desired by the operator is not properly set. There was room for improvement in terms of operability.

An object of the present invention is to provide a turning control device for a working vehicle which makes it possible to express a desired turning state by a simple operation.

[0007]

According to the characteristic construction of claim 1, the turning operation tool has a straight-ahead command position, a non-drive turning position, a gentle turning position, a ground turning position, and a super-ground turning. It is configured so that it can be sequentially switched to the position. Then, when the turning operation tool is operated from the straight-ahead command position to the non-drive turning position, the traveling device located on the turning side is switched to the non-drive turning state in which the free-spinning state is set, and the turning operation tool is moved to the gentle turning position. When operated, the traveling device located on the turning side is switched to a gentle turning state in which the traveling device is driven at a lower speed than the other traveling device,
When the turning operation tool is operated to the pivot turning position, the traveling device located on the turning side is switched to the transmission turning state in which the transmission is stopped and the braking is performed, and the turning operation tool is operated to the super turning pivot. Then, the left and right traveling devices are switched to the super-spot turning state in which they are driven in opposite directions.

That is, the operator sequentially switches the operation position of the turning operation tool from the straight-ahead command position, whereby the turning of the non-driving turning state, the gentle turning state, the ground turning state, and the super-field turning state is performed. The states can be made to appear in order, and the desired turning state corresponding to the working state can be easily made to appear by a simple operation of operating the turning operation tool to any corresponding operating position. There is no need for troublesome operations such as switching between different switching means or adjusting the operating force.
The operability in the turning operation can be improved.

Further, according to the characterizing feature of claim 1, wherein the turning operation unit, slow turning is operated by a hydraulic force transmission state of the slow turning of driving left and right traveling devices respectively different rates Friction clutch for friction, a friction brake for pivotal turning operated by hydraulic pressure in a braking state in which the traveling device on the turning side of the left and right traveling devices is braked,
Each of the friction clutches and the friction clutches for super-complex turning, which is operated by hydraulic pressure in a transmission state for super-confidence turning for driving the left and right traveling devices in opposite directions, is provided. Detects the hydraulic operation mechanism that selectively operates the automatic brake, the turning direction selected from the left and right directions of the turning operation tool, and the operation amount in the selected turning direction from the straight-ahead command position. And a control means for controlling the hydraulic operation mechanism based on the detection result of the operation state detection means.

That is, the turning direction and the operation amount of the turning operation tool are detected by the operation state detecting means, and based on the detection result, the turning operation position is the position corresponding to the gentle turning position. When the judgment is made, the control means controls the hydraulic operation mechanism so as to operate the friction clutch for gentle turning with hydraulic pressure. In the same manner, the frictional brake for the pivotal turning and the frictional clutch for the super pivotal turning are respectively corresponded to the operations of the pivotal turning position and the super pivotal turning position by the turning operation tool. The hydraulic operating mechanism is controlled so that it is operated by hydraulic pressure. That is, the control means
By selectively operating each of the friction clutches and the friction brakes with hydraulic pressure, each turning operation state is revealed.

As a turning operation mechanism for displaying the above-described gentle turning state, super-spinning turning state, etc., for example, a gear is operated by an actuator to shift the transmission state to switch the transmission state, and an interrupting means provided in the middle of transmission. In the actuator, the transmission is cut off prior to the gear shift operation, and after the gear shift operation, the transmission is turned on again, so that the slow turning state, the super-spinning turning state, or the like can be realized. Compared with such a turning operation mechanism, according to the present invention, the operation for changing the turning state can be performed quickly by adopting the configuration of selectively operating the hydraulically operated friction clutch and friction brake as described above. It can be done smoothly and smoothly.

Further, according to the characterizing feature of claim 1, wherein the hydraulic operation mechanism is configured by a pressure adjusting means for adjusting changes the hydraulic pressure for each friction clutch and friction brake, the The control means increases the hydraulic pressure as the operating amount of the turning operation tool increases, and the rate of change of the hydraulic pressure is small in a region where the operating amount is small. Is set to be large in the large region, and the change characteristic is set to control the operation of the pressure adjusting means.

Therefore, among the friction clutches and friction brakes, the one corresponding to the position where the turning operation tool is operated is operated by hydraulic pressure. As the manipulated variable increases, the hydraulic pressure increases, and the rate of change in hydraulic pressure decreases in the region where the manipulated variable is small and increases in the region where the manipulated variable is large. As a result, as the operation amount of the turning operation tool increases, the hydraulic pressure, that is, the power transmission force in the clutch or the braking force in the brake increases, and the force increases as the operation amount increases. It is possible to bring out a turning state that matches the human operation feeling.

According to the characteristic configuration of claim 2 , the hydraulic operation mechanism causes the hydraulic operation mechanism to adjust the pressure of the hydraulic pressure adjusted by the pressure adjusting means for each of the friction clutches and the friction brakes. It is configured to include an oil passage switching unit that switches an oil passage for supplying hydraulic oil so that oil is selectively supplied, and the control unit switches the oil passage so as to correspond to an operation position of the turning operation tool. It is configured to switch the means.

Therefore, the hydraulic oil having the hydraulic pressure adjusted by the pressure adjusting means is supplied to one of the friction clutches and friction brakes selected by the oil passage switching means. The pressure adjusting means can be used in common, and the structure can be simplified by using the members in common as compared with the structure in which the pressure adjusting means is separately provided for each of the friction clutches and the friction brakes. .

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION A turn control apparatus for a combine as an example of a work vehicle according to the present invention will be described below with reference to the drawings. As shown in FIG. 1, a combine, which is an example of a work vehicle, includes a pair of left and right traveling devices 1L, 1 of a crawler type.
A cutting unit 3 for cutting the planted culms and transporting them to the rear is connected to the front part of the machine body frame 2 provided with R so as to be vertically movable,
The machine frame 2 includes a threshing device 4 for threshing the cut culms from the reaping unit 3 and a boarding operation unit 5.

Engine E mounted on the body frame 2
As shown in FIG. 2, a transmission system from the traveling devices 1L and 1R to the traveling devices 1L and 1R includes a hydrostatic stepless transmission 7 which is a main transmission and is capable of forward / reverse switching, and a sub-transmission 8 having a three-stage switching.
And the turning transmission mechanism 9 are provided in that order. A manual gear shift operating lever 7L for shifting the continuously variable transmission 7 is provided in the boarding operation section 5.

The continuously variable transmission 7 includes traveling devices 1L and 1L.
The output shaft 7A is attached to the mission case 11 supporting the respective axles 10L and 10R of the R in a state of being inserted. The auxiliary transmission 8 and the turning transmission mechanism 9
Is installed in the mission case 11. An intermediate transmission shaft 14 to which power is transmitted from the output shaft 7A of the continuously variable transmission 7 via the gear pairs 12 and 13 is supported on the transmission case 11 with one end thereof protruding outward. A reaper output pulley 15 for transmitting power to the reaper 3 is attached to an outer end portion of the intermediate transmission shaft 14, and the intermediate transmission shaft 14 and the reaper output pulley 15 are provided.
A one-way clutch 16 that transmits only the forward rotation of the intermediate transmission shaft 14 to the reaping output pulley 15 is interposed between and.

The power of the intermediate transmission shaft 14 is transmitted to the input shaft 8A of the auxiliary transmission 8 through a pair of gears 17 and 18, and is provided between the input shaft 8A and the output shaft 8B. The transmission system for low speed transmission, the transmission system for medium speed transmission, and the transmission system for high speed transmission have three different transmission ratios, and each transmission system is selectively used. By selecting and using it, three-speed shifting is performed.

The transmission system for low speed transmission is the input shaft 8
The first transmission gear G1 is attached to A so as to rotate integrally, and the first passive gear g1 which meshes with and interlocks with the first transmission gear G1 is attached to the output shaft 8B so as to be rotatable with respect to the output shaft 8B. A wet multi-plate type first hydraulic clutch C1 is provided between the first passive gear g1 and the output shaft 8B so as to connect and disconnect the transmission from the first passive gear g1 to the output shaft 8B.

The transmission system for medium speed transmission is the input shaft 8
A is installed in a state in which the second transmission gear G2 is integrally rotated, and a second passive gear g2 that meshes with and interlocks with the second transmission gear G2 is installed in the output shaft 8B in a rotatable state with respect to the output shaft 8B. A wet multi-plate second hydraulic clutch C2 is provided between the second passive gear g2 and the output shaft 8B so as to connect and disconnect the transmission from the second passive gear g2 to the output shaft 8B.

The transmission system for high speed transmission is the input shaft 8
The third transmission gear G3 is attached to A so as to rotate integrally, and the third passive gear g3 which meshes with and interlocks with the third transmission gear G3 is attached to the output shaft 8B so as to be rotatable with respect to the output shaft 8B. Between the third passive gear g3 and the output shaft 8B, a wet multi-plate third hydraulic clutch C3 for connecting and disconnecting the transmission from the third passive gear g3 to the output shaft 8B is provided.

The first, second and third hydraulic clutches C
As shown in FIG. 3, each of 1, C2, C3 resists the biasing force of the spring PB as the pressure oil is supplied to the oil chamber r via the hydraulic circuits L1, L2, L3. It is a positive hydraulic clutch that is switched to a clutch engaged state for transmission, and is switched to a clutch disengaged state in which transmission is disengaged by the biasing force of the spring PB as oil is discharged from the oil chamber r.

The sub-transmission device 8 has a structure of <1> first
The hydraulic oil is supplied to the hydraulic clutch C1 of the first hydraulic clutch C1 to switch the first hydraulic clutch C1 to the clutch-engaged state, and
By discharging the oil from the hydraulic clutch C2 and the third hydraulic clutch C3 and switching the second and third hydraulic clutches C2 and C3 to the clutch disengaged state, only the transmission system for low speed transmission is switched to the transmission state. The transmission state (falling speed) is established, and <2> pressure oil is supplied to the second hydraulic clutch C2 to switch the second hydraulic clutch C2 to the engaged state, and the first hydraulic clutch C1 and the third hydraulic clutch C3
By draining oil from the hydraulic clutch C3 and switching the first and third hydraulic clutches C1 and C3 to the clutch disengaged state, only the transmission system for medium speed transmission is switched to the transmission state. ), <3> pressure oil is supplied to the third hydraulic clutch C3 to switch the third hydraulic clutch C3 into the clutch-engaged state, and the third hydraulic clutch C3 is discharged from the first hydraulic clutch C1 and the second hydraulic clutch C2. By oiling and switching the first and second hydraulic clutches C1 and C2 to the clutch disengaged state, a high speed transmission state (moving traveling speed) in which only the transmission system for high speed transmission is switched to the transmission state, <4> Oil is discharged from the first hydraulic clutch C1, the second hydraulic clutch C2, and the third hydraulic clutch C3, and the first, second, and third hydraulic clutches C1,
By switching C2 and C3 to the clutch disengaged state, a neutral state is achieved in which the entire transmission system is switched to the non-transmission state.

As a shift operating means of the sub transmission device 8,
As shown in FIG. 4, the hydraulic pump P and the hydraulic circuits L for the first, second and third hydraulic clutches C1, C2 and C3 are shown.
1, L2, L3, the respective hydraulic clutches C1, C2,
A speed change control valve B1 for supplying pressure oil to any one of C3 and for discharging the remaining hydraulic clutch, and pressure oil from the hydraulic pump P is supplied to the speed change control valve B1. Pressure oil supply state to be turned on, and pressure oil supply to the speed change control valve B1 is stopped to cause the hydraulic clutches C1, C2,
A neutral switching valve B2 is provided which can be switched from C3 to a drained state in which oil is drained.

Here, the shift control valve B1 is a three-position switching type solenoid valve, and is provided with solenoids sb1 and sb2 for switching operation on the left and right. When both solenoids sb1 and sb2 are not energized, the oil passage switching spool is set to the spring so that the pressure oil is supplied to the hydraulic circuit of the second hydraulic clutch C2 (for standard speed). When the solenoid sb1 on the left side is energized by being urged to return to the middle position by the, the state in which pressure oil is supplied to the first hydraulic clutch C1 (for the fall speed) is switched, and the solenoid sb2 on the right side is energized. When done,
It is configured to switch to a state in which pressure oil is supplied to the third hydraulic clutch C3 (for traveling speed). The neutral switching valve B2 is configured as a two-position switching electromagnetic valve, is biased to return to the pressure oil supply state by a spring, and is configured to switch to the oil discharge state by energizing the solenoid.

As shown in FIGS. 5 and 6, the grip operation portion of the gear shift operation lever 7L is provided with a push button type first switch SU and a sub gear shift operation portion 62 including a second switch SD. Based on the information input from each switch SU, SD, the first and second electromagnetic control valves B1,
A control device 60 for controlling the operation of B2 is provided.
The control device 60 is configured to include a microcomputer, and based on the operation of each switch, the neutral switching valve B2
Is switched to the oil draining state, the neutral switching valve B2 is in the pressure oil supplying state, and the shift control valve B1 is in the low speed transmission state in which the pressure oil is supplied only to the first hydraulic clutch C1, the neutral switching valve B.
2 is in the pressure oil supply state, the speed change control valve B1 is in the medium speed transmission state in which pressure oil is supplied only to the second hydraulic clutch C2, the neutral switching valve B2 is in the pressure oil supply state, and the speed change control valve B1 is in the third state. It is configured to control each valve so as to switch to each state of the high speed transmission state in which the pressure oil is supplied only to the hydraulic clutch C3.

As a concrete switching operation, every time the first switch SU is turned on, the shift control valve B1 and the neutral switching valve B2 are sequentially switched to the high speed side, and the second switch S is operated.
Each time D is turned on, the control valves B1 and B2 are switched to the low speed side in sequence. More specifically, FIG.
As shown in, when the auxiliary transmission 8 is in the neutral state N, when the first switch SU is turned on, the low speed transmission state F1 is established, and when it is in the low speed transmission state F1, the first switch SU is
When the ON operation is performed, the medium speed transmission state F2 is set, when the first switch SU is turned on in the medium speed transmission state F2, the high speed transmission state F3 is set, and when the second switch SD is turned on when the high speed transmission state F3 is set. Medium speed transmission state F2
And the second switch S when in the medium speed transmission state F2.
When D is turned on, the low-speed transmission state F1 is set. When the second switch SD is turned on while the low-speed transmission state F1 is set, the neutral state N is set. In the initial stage of operation when the control device 60 is powered on, the shift control valve B1 is in the medium speed transmission state, and the neutral switching valve B2 is initially set in the pressure oil supply state.

Further, as shown in FIG. 2, a wet multi-plate type parking brake 19 for braking the output shaft 8B to stop and hold the traveling devices 1L, 1R is provided, and the parking brake 19 is shown in FIG. As shown in the figure, the spring 1 is configured so that it is braked by the urging force of the spring 19b and the spring 1 is supplied as the hydraulic pump P is operated to supply the pressure oil.
A negative-type brake cylinder 19a is provided which extends the brake 9b to release the braking state against the urging force of 9b, and automatically returns to the braking state when the engine stops in the middle of a slope. Is configured.

Next, the turning transmission mechanism 9 will be described with reference to FIG. Output shaft 8B of the auxiliary transmission 8
In addition, a forward rotation transmission gear 33 is mounted in an integrally rotating state, and a forward rotation transmission passive gear that meshes with the forward rotation transmission gear 33 and is linked to a shift shaft 31 rotatably supported by the transmission case 11. The gear 34 is mounted so as to rotate integrally. Further, the shift shaft 31 includes a pair of left and right steering passive gears 35L and 35R, and the axle shaft 10.
A pair of left and right shift gears 39L and 39R, which are always meshed with and interlocked with vehicle bearing dynamic gears 36L and 36R, which are mounted to rotate integrally with L and 10R, are rotatably mounted. Then, the left and right shift gears 39L, 39R
Of the left and right car bearing dynamic gears 36 by moving the
L and 36R are meshing linear clutches 37L and 37
A first gear that interlocks with the normal rotation transmission passive gear 34 via R
It is configured to be switchable between a state and a second state in which the passive steering gears 35L and 35R are interlocked with each other via the meshing type steering clutches 38L and 38R.

A deceleration / reverse rotation braking shaft 40 is rotatably supported by the mission case 11, and the deceleration / reverse braking shaft 40 is rotatably supported.
The steering transmission gears 41L and 41R, which equally reduce the speed of the rotation of the steering passive gears 35L and 35R, are mounted on the deceleration / reverse braking shaft 40 so as to rotate integrally with the steering passive gears 35L and 35R. The forward rotation passive gear 43, which meshes with the transmission gear portion 42 formed integrally with the gear 34 and transmits the rotation of the forward rotation transmission passive gear 34 by deceleration, is rotatably mounted on the deceleration / reverse rotation braking shaft 40. There is. Then, between the forward rotation passive gear 43 and the deceleration / reverse rotation braking shaft 40, the transmission from the forward rotation passive gear 43 to the deceleration / reverse rotation braking shaft 40 is interrupted when the pressure oil supply is stopped. A wet multi-plate hydraulic clutch 45 for deceleration (corresponding to a friction type clutch for gentle turning) is provided that is energized and switches to a clutch-engaged state in which transmission is performed against the urging force when pressure oil is supplied. There is. That is, the hydraulic clutch 4
When the clutch 5 is actuated, the rotation of the normal rotation transmission passive gear 34 is transmitted to the transmission gear portion 42 and the normal rotation passive gear 43.
The deceleration clutch 45, the deceleration reverse rotation braking shaft 40, the steering transmission gears 41L and 41R, and the steering passive gears 35L and 35R are transmitted to drive the car bearing dynamic gears 36L and 36R in synchronous deceleration. .

A reverse rotation transmission passive gear 47, which meshes with and interlocks with a reverse rotation transmission gear 46 mounted integrally on the output shaft 8B of the auxiliary transmission 8, is rotatably attached to the deceleration reverse braking shaft 40. A spring is placed between the reverse gear transmission passive gear 47 and the deceleration reverse rotation braking shaft 40 in a clutch disengaged state that cuts off the transmission from the reverse rotation transmission passive gear 47 to the deceleration reverse rotation braking shaft 40 when the pressure oil supply is stopped. Via a wet multi-plate hydraulic clutch 49 for reverse rotation (corresponding to a friction clutch for super-spot turning), which is urged through the operation and is switched to a clutch engagement state in which transmission is performed against the urging force when pressure oil is supplied. ) Is provided. That is, by operating the hydraulic clutch 49 to be engaged, the rotation of the reverse rotation transmission gear 46 is changed to the reverse rotation passive gear 47 / reverse rotation clutch 4.
9. Deceleration / reverse rotation braking shaft 40 / steering transmission gears 41L, 41
It is configured to be transmitted to the R / steering passive gears 35L and 35R to drive the car bearing dynamic gears 36L and 36R in a synchronous reverse rotation.

Further, when the pressure oil supply is stopped, the deceleration reverse rotation braking shaft 4
A wet multi-plate hydraulic brake 50 for braking, which is urged by a spring to a clutch disengaged state for braking 0 and reversibly brakes the deceleration / reverse braking shaft 40 against the urging force associated with the supply of pressure oil. (Corresponding to a friction brake for turning the ground) is provided. That is, by operating the hydraulic brake 50, the deceleration / reverse rotation braking shaft 40, the steering transmission gears 41L and 41R, and the steering passive gears 35L and 35R are transmitted to brake the car bearing dynamic gears 36L and 36R. Is configured.

That is, the turning transmission mechanism 9 causes the rotation of the forward rotation passive gear 34 to rotate in both vehicle bearings via both shift gears 39L and 39R by <1> actuating both of the linear clutches 37L and 37R into engagement. Gear 36L,
36R, the left and right traveling devices 1L and 1R are driven at a constant speed in a straight traveling state. <2> Steering clutch 38
A non-driving turning state in which the driving of one of the left and right traveling devices 1L and 1R is turned off and a free idling state is set by operating the turning side of L and 38R with a clutch. <3> Steering Of the clutches 38L and 38R, the one on the turning side is engaged with the clutch, and the hydraulic clutch 45 for deceleration is also engaged on the clutch, so that the traveling device 1L or 1R on the turning side of the passive steering gears 35L and 35R is operated. By driving the left and right traveling devices 1L and 1R, the driving speed of the one on the turning side is made slower than the driving speed of the one on the outside of the turning to make a gentle turning state. <4> Steering clutches 38L, 38R Of the turning devices, the one on the turning side is engaged with the clutch and the hydraulic brake 50 for braking is actuated, so that the traveling device 1L on the inside of the turning or For steering the R passive gear 35L or 35
In the pivotal turning state in which braking is stopped via R to perform pivotal turning, <5> The steering clutch 38L or 38R, which is on the turning side, is engaged and the hydraulic clutch 49 for reverse rotation is engaged. By driving the driving device 1L or 1R on the inner side of the turning by the one on the inner side of the turning of the steering passive gears 35L, 35R, the one on the inner side of the turning of the left and right traveling devices 1L, 1R is driven in reverse. It is configured so that the switching operation can be performed in each of the super-confidential turning state in which the super-confidential turning is performed.

As an operating means of the turning transmission mechanism 9, FIG.
As shown in FIG. 3, the shift gears 39L and 39R are respectively moved to the positions where the straight clutches 37L and 37R are engaged.
A pair of left and right springs 52 for urging and moving via L and 51R
The shift gears 39L and 3R are opposed to the biasing forces of the springs 52L and 52R by extending the L and 52R together with the pressure oil supply.
A pair of left and right steering cylinders 53L and 53R for moving the respective 9Rs to the positions where the steering clutches 38L and 38R are engaged via the arms 51L and 51R are provided, and pressure oil is provided to the left and right steering cylinders 53L and 53R. A pair of left and right electromagnetically operated directional control valves 56L, 56R are provided which can be switched between a state of supplying oil and a state of discharging oil.

Further, the left and right steering cylinders 53L, 53
When either R is in the extension operation state, the pressure oil supplied from the steering cylinders 53L, 53R via the oil passage 54 is supplied to the hydraulic clutch 45 for deceleration and the hydraulic oil for reverse rotation. An electromagnetically operated steering control valve 55 is provided as an oil passage switching means for mode switching that is switchable between a reverse rotation state in which it is supplied to the clutch 49 and a braking state in which it is supplied to the hydraulic brake 50 for braking. Incidentally, the oil passage 54
A pressure adjustment for adjusting the hydraulic pressure (that is, the turning force) of the working oil supplied to each of the hydraulic clutches 45 and 49 and the hydraulic brake 50 based on the operation state of a turning operation lever 58 described later. Pressure adjusting valve 57 as means Q
Is provided. The pressure adjusting valve 57 is composed of an electromagnetic proportional pressure control valve, and switches the spool, which is biased to return to the oil discharge side by a spring, to the pressure oil supply side by energizing the electromagnetic solenoid. By changing and adjusting the current supplied to the solenoid, the position of the spool is changed so that the hydraulic pressure of the hydraulic oil can be changed and adjusted.

Each of the direction switching valves 56L, 56R, the steering control valve 55, and the pressure adjusting valve 57 is operated based on the operation of a turning operation lever 58 as a turning operation tool provided in the boarding operation section 5, based on the operation. The control device 60 is configured to perform a switching operation. More specifically, the turning operation lever 5
8 is provided with a potentiometer 61 as an operation state detecting means for detecting the operation state of the swing fulcrum, and the control device 60 determines the operation position of the turning operation lever 58 on the basis of the detection information, and each of the valves is operated. It is designed to switch between. That is, as shown in FIG. 5, as the turning operation lever 58 swings from the straight-ahead command position TS to either the left or right direction, the non-driving turning position (R1, L1), the gentle turning position (R2, L2). , Turning position (R3, L
3), the turning operation lever 58 is configured so that it can be sequentially switched to each of the super-position turning positions (R4, L4).
The control device 60 executes the control as described below when the vehicle swings from the straight-ahead command position TS in either the left or right direction. When the turning operation lever 58 is located at the straight travel command position TS, the bidirectional switching valves 56L and 56R are switched to the oil draining state and the pressure adjusting valve 57 is switched to the inoperative state (straight traveling state). When the turning operation lever 58 is in the non-driving turning position (L1 or R
When operated to 1), the directional switching valve (56L or 56R) on either the left or right side is switched to the pressure oil supply state and the pressure adjusting valve 57 is switched to the non-operating state (non-drive turning state). The turning operation lever 58 is in the gently turning position (L2 or R2)
When it is operated to, the direction switching valve (56L or 56R) on either the left or right side is switched to the pressure oil supply state, the pressure adjusting valve 57 is switched to the operating state, and the steering control valve 55 is switched to the deceleration state. (Slow turning state). The turning operation lever 58 is set to the solid turning position (L3 or R
When operated in 3), the direction switching valve (56L or 56R) on either the left or right side is switched to the pressure oil supply state, the pressure adjusting valve 57 is switched to the operating state, and the steering control valve 55 is in the braking state. Switch to (Turning to the ground). The turning operation lever 58 moves to the super-sight turning position (L4 or R
4), the direction switching valve (56L or 56R) on either the left or right side is switched to the pressure oil supply state, the pressure adjusting valve 57 is switched to the operating state, and the steering control valve 55 is in the reverse rotation state. Switch to (super turning state).

The control device 60 includes a turning operation lever 58.
The hydraulic pressure in each of the hydraulic clutches 45 and 49 and the hydraulic brake 50 increases as the turning operation amount increases, and the rate of change of the hydraulic pressure is small in the region where the operation amount is small. Is configured to be large in the large region, and the change characteristic is set to control the operation of the pressure control valve.

More specifically, as shown in FIG. 8, as the turning operation amount of the turning operation lever 58 increases from the straight-ahead command position TS, the turning state is switched as described above, and at the same time,
Among the hydraulic clutches 45, 49 and the hydraulic brake 50, the change characteristic of the hydraulic pressure with respect to the operation amount for the one selected corresponding to each operation position (region) is
It is set to be non-linear so that the change rate increases as the operation amount increases. With such a configuration, the human operation interval with respect to the lever operation corresponds to the actual turning operation state of the vehicle body, and the operability is excellent.

Therefore, the directional control valves 56R, 56L,
The steering control valve 55, the pressure adjusting valve 57, the hydraulic pump P, and the like constitute a hydraulic operating mechanism, and the hydraulic operating mechanism, the turning transmission mechanism 9, the control device 60, and the like constitute a turning operating means. become.

[Other Embodiments] (1) In the above embodiment, each of the hydraulic clutches 45, 4 is
9 and the hydraulic brake 50, the oil for switching the oil passage for supplying the hydraulic oil so that the pressure oil having the oil pressure adjusted by the pressure adjusting valve 57 as the pressure adjusting means Q is selectively supplied. Although the configuration including the three-position switching type steering control valve 55 as the path switching means has been exemplified, the following configuration may be used instead of such a configuration.

As shown in FIG. 9, each hydraulic clutch 4
5, 49 and hydraulic brakes 50 are respectively provided with pressure adjusting valves 63, 64, 65 in the pressure oil supply passages,
It is also possible to selectively actuate one of the pressure adjusting valves to actuate any one of the hydraulic clutches 45, 49 and the hydraulic brake 50, and also to perform pressure adjustment separately. Therefore, each of the pressure adjusting valves 63, 64, 65 constitutes the pressure adjusting means Q.

(2) In the above embodiment, the case where the swing operation lever for swinging operation is used as the swing operation tool is exemplified. However, instead of such a swing operation type operation tool, a steering handle of a passenger car is used. A rotary operation type turning operation tool may be used.

[0044]

[0045]

[0046]

The present invention can be applied to various work vehicles other than combine harvesters.

[Brief description of drawings]

FIG. 1 Side view of combine

FIG. 2 is a diagram showing a traveling transmission structure.

FIG. 3 is a vertical sectional front view of the auxiliary transmission device.

[Fig. 4] Hydraulic circuit diagram

FIG. 5 is a control block diagram.

FIG. 6 is a diagram showing an auxiliary shift operation unit.

FIG. 7 is a diagram showing an operating state of the auxiliary transmission device.

FIG. 8 is a characteristic diagram showing changes in hydraulic pressure.

FIG. 9 is a hydraulic circuit diagram of another embodiment.

[Explanation of symbols]

1R, 1L traveling device 45,49 Friction clutch 50 friction brake 55 Oil passage switching means 58 Turning operation tool 60 control means Q Pressure adjusting means

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-1-101272 (JP, A) JP-A-7-47973 (JP, A) JP-A-4-118384 (JP, A) JP-A-2- 45276 (JP, A) JP-A-8-19304 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B62D 11/00

Claims (2)

(57) [Claims] 1. A turning control device for a working vehicle, comprising: a pair of left and right traveling devices; and a turning operation means for switching a turning operation state of each of the running devices based on a turning command operation of a turning operation tool. The turning operation tool is configured to be sequentially switchable to each of a straight-ahead command position, a non-driving turning position, a gentle turning position, a land turning position, and a super land turning position, and the turning operation means is the turning operation tool. Is operated to the non-drive turning position,
When the traveling device located on the turning side is switched to a non-driving turning state in which the traveling device is in a free-spin state, and the turning operation tool is operated to the gentle turning position, the traveling device located on the turning side is the other traveling device. When the turning operation tool is switched to a slower turning state that is driven at a lower speed, and the turning operation tool is operated to the turning point position, the traveling device located on the turning side is in the transmission stopped state and is braked Switching to a state, when the turning operation tool is operated to the super-trust turning position ,
The left and right traveling devices are configured to switch to a super-spot turning state in which the left and right traveling devices are driven in opposite directions, and the turning operation means is for gentle turning in which the left and right traveling devices are driven at different speeds.
A friction type clutch for gentle turning that is operated by hydraulic pressure in the transmission state.
Switch on the turning side of the left and right running devices
In response to the braking state in which the braking action is applied, hydraulic pressure is used.
Friction brakes for turning the ground, the left and right traveling devices to each other
To hydraulic pressure in the transmission state for super-infrared turning driven in the opposite direction
Equipped with friction clutches for super-spinning
In addition, the friction clutches and brakes are selectively operated.
Hydraulic operating mechanism to be created and left and right of the turning operation tool
Turning direction selected from either direction and going straight
Detects the operation amount in the selected turning direction from the command position
Operating state detecting means and the detection result of the operating state detecting means.
Control means for controlling the hydraulic operation mechanism based on the result
And the hydraulic operation mechanism includes the friction clutches and the friction clutches.
Pressure adjusting means for changing and adjusting the hydraulic pressure for the hydraulic brake
The control means is configured to include the slow turning position and the signal of the turning operation tool.
Greatly increases the operation amount at each of the ground turning position and the supertrust turning position.
As the oil pressure increases, the oil pressure increases and the oil pressure
The rate of change is small in the region where the operation amount is small, and
Change characteristics so that the amount of production is large in the large area
To control the operation of the pressure adjusting means.
A turning control device for the work vehicle that is configured . 2. The hydraulic operation mechanism comprises:
For each of the latch and friction brake, the pressure adjustment
Pressure oil of the hydraulic pressure adjusted by the node means is selectively supplied.
Passage switching means for switching the oil passage for supplying hydraulic oil
And the control means corresponds to an operation position of the turning operation tool.
Is configured to switch the oil passage switching means.
Work vehicle turning control device according to claim 1, wherein there.