JP2000264243A - Turning control device for working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily produce an appropriate turning operating state according to a working state by selecting a specified turning operating state immediately upon the shift of a turning operating means into a turning command position, and selecting the other turning operating state when a shift command state into this turning command position continues for the set time or longer. SOLUTION: A lateral pair of solenoid operated directional control valves 56L, 56R shiftable into each state of supplying and discharging pressure oil to and from both lateral steering cylinders, and a steering control valve 55 shiftable into each state of individually supplying and discharging pressure oil to and from a plurality of pressure oil clutches and a pressure oil brake, are respectively shift-operated by a control device 60 according to the operation of a turning operating lever 58 and the operation of a mode setter 62. The control device 60 immediately commands a straight advancing travel state if the turning operating lever 58 is in a straight advance command position TS. When the state of the turning operating lever 58 being operated into first operating areas L1, R1 continues for the set time or longer, the control device 60 commands a shift into second operating areas L2, R2 larger in turning force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turning control device for a working vehicle such as a combine, for example.
Turning operation means operable to switch the driving state of the pair of left and right traveling devices between a straight traveling state, a first turning operation state having a small turning force, and a second turning operation state having a larger turning force; A working vehicle provided with a turning operation tool that can be switched between a straight-moving command position for commanding traveling and a turning command position for commanding switching to a turning state, and control means for controlling the operation of the turning operation means. The present invention relates to a turning control device.

[0002]

2. Description of the Related Art A conventional turning control device for a working vehicle has a configuration as disclosed in Japanese Patent Application Laid-Open No. 4-118385. In this configuration, when the operation lever (39) serving as the turning operation tool is moved from the neutral position (N), which is the straight forward command position, to the right or left turning side by a predetermined amount and operated to the first turning position (R1 or L1). ,
A turning state in which the transmission to the turning-side traveling apparatus of the left and right traveling apparatuses is cut off and the turning force is small (first turning operation state).
Becomes Then, when the operation lever (39) is further moved and operated to the second turning position (R2 or L2), the second turning operation state is changed to a turning state in which the driving speeds of the pair of left and right traveling devices are different from each other. A friction hydraulic clutch (12) for turning, and a friction hydraulic brake (2) for pivot turning for braking a turning-side traveling device of the traveling devices.
8) Supply of pressurized oil to a selected one of the friction hydraulic clutches (30) for turning corners for driving the respective traveling devices in directions opposite to each other is started, and the operation lever (39) is operated. The operating lever (39) and the variable relief valve (36) for adjusting the hydraulic pressure are connected via a link mechanism such as a wire so that the operating pressure by the hydraulic pressure increases and the turning force increases with the further moving operation of the lever. There was one that was configured to be linked and linked.

[0003]

For example, in the case of a combine harvester as an example of this type of work vehicle, when performing a mowing work in a field or the like, the above-mentioned turning operation is performed by enlarging a vehicle body in a headland or the like. Not only when turning and turning the direction, but also when cutting and harvesting the planted grain culm while running the car straight, make the car body travel as much as possible along the planting row of planted grain culm. For this reason, a turning operation may be performed to correct the direction. As described above, when the vehicle body is largely turned on a headland or the like, it is more efficient to turn in a turning state that exerts a large turning force, but less turning is necessary when performing a direction correction or the like when going straight. It is better to perform the turning operation little by little, and when turning with a large turning force, the turning amount (correction amount) becomes too large.

However, in the above-mentioned conventional configuration,
When the steering lever is operated to the first turning position (R1 or L1), the turning operation is performed in a turning state with a small turning force, but the operating lever is erroneously turned to the second turning position (R1).
2 or L2), the turning operation is immediately performed in a turning state with a large turning force. Then, for example, as described above, when the direction is to be corrected in the case where the harvesting operation is performed while the vehicle body is traveling straight, it is preferable to perform the turning operation at the first operation position where the turning force is relatively small. There is a possibility that the operation may be performed up to the second operation position due to an error. As a result, there is a disadvantage in that the turning operation is immediately performed by a large turning force and the correction amount becomes too large, and it is rather difficult to correct the direction.

[0005] In order to avoid such a disadvantage, the steering lever is not switched to the second operation position unless the steering lever is largely swung with an interval between the first operation position and the second operation position. With such a configuration, there is a disadvantage that the operation becomes difficult when the vehicle body is largely turned.

The present invention has been made in view of such a point, and an object of the present invention is to provide a work vehicle turning control device capable of easily showing an appropriate turning operation state according to a work situation. The point is to provide.

[0007]

According to a characteristic feature of the invention according to claim 1, the control means is configured to switch the turning operation tool to the straight traveling state as soon as the turning operation tool is switched to the straight traveling command position. When the operation of the operating means is controlled, the turning operation tool is switched to the first turning operation state immediately when the turning operation tool is switched to the turning command position, and when the switching command state to the turning command position continues for a set time or more, It is configured to control the operation of the turning operation means so as to switch to the second turning operation state.

Accordingly, when the turning operation tool is switched to the straight-moving command position, it is immediately switched to the straight traveling state, and immediately when it is switched to the turning command position, it is switched to the first turning operation state having a small turning force. Then, when the switching command state to the turning command position continues for the set time or more, the state is switched to the second turning operation state in which the turning force is large. That is,
If the switching command state of the turning operation tool to the turning command position is less than the set time, the turning force is maintained in the first turning operation state with a small turning force, and is not switched to the second turning operation state.
If the switching command state continues for a set time or more, the state is switched to the second turning operation state in which the turning force is large.

As a result, for example, when the vehicle body is slightly turned during straight traveling and the direction is corrected so that the vehicle body follows the set route, the switching command state by the turn command means is manually operated so as to be less than the set time. This makes it possible to perform an appropriate turning operation in a state of good responsiveness and with a small turning force, and when it is desired to make a large turn to change the direction of the vehicle body, the turning operation tool is used. By manually operating the switching command state so as to continue for a set time or more, the vehicle can be efficiently turned with a large turning force, and an appropriate turning operation state can be easily displayed according to the work situation. It has become possible to provide a work vehicle turning control device that can be used.

According to a second aspect of the present invention, in addition to the first aspect of the present invention, the turning operation tool is provided so as to be freely movable over a predetermined moving width at the turning command position. An operation amount detecting means for detecting an operation amount of the operating tool toward the turning side at the turning command position is provided, and the control means has a shorter time as the moving operation amount detected by the operation position detecting means is larger. like,
The point is that the set time is changed and set.

For example, when it is desired to make a large turn in order to change the direction of the vehicle body, by increasing the amount of operation of the operating tool toward the turning side, the operation until switching to the second turning operation state is performed. The time required for continuation (set time) is shortened, and it is possible to switch to the second turning operation state in which the turning force is large as quickly as possible. As a result, when it is desired to make a large turn, for example, it is possible to improve the efficiency of the turning operation by minimizing the response delay.

According to a third aspect of the present invention, in addition to the first or second aspect of the present invention, the turning operation means includes a pair of right and left traveling devices in the first turning operation state. Of the above, the traveling device located on the turning side is in a free idling state, and the traveling device located on the opposite side is configured to be switched to a non-drive turning state in which the driving device is in a driving state, and as the second turning operation state, The traveling device located on the turning side is in the power transmission stopped state and is braked, and the traveling device located on the opposite side is in the driving state, and the traveling device located on the turning side is higher than the other traveling device. Is also configured to switch between a slow turning state driven at a low speed and a super turning state in which the left and right traveling devices are driven in opposite directions.

Therefore, when a command to switch from the straight running state to the turning state is issued by the turning command means by manual operation, the turning operation means immediately switches to the non-drive turning state. That is, the traveling device located on the turning side is in a free idling state, and the traveling device on the opposite side is driven to turn. When the switching command state by the turning command means continues for a set time or more, the second turning operation state in which the turning force is large is switched to one of a pivot turning state, a gentle turning state, and a super turning state. Will be replaced. In the pivot turn state, the traveling device located on the turning side is in the power transmission stopped state and is braked, and drives the traveling device on the opposite side to make a turn. Although the turning force is large, the turning force is small as compared with the gentle turning state and the super turning state. In the gentle turning state, the left and right running devices are driven at different speeds while the traveling device located on the turning side is driven at a lower speed than the other traveling device. Is large, but the turning force is small as compared to the super turning state. In the pivot turn state, the left and right traveling devices are driven in opposite directions to each other, so that a larger turning force can be obtained than in the gentle turning state, and the turning can be performed with a small turning radius.

As a result, by selecting one of the turning states having different turning forces, an appropriate turning state can be made to appear according to the work situation, and the work efficiency is improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A turning control device for a combine as an example of a working 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 crawler traveling devices 1L, 1L.
A cutting unit 3 that cuts the planted grain culm and conveys it rearward is connected to the front part of the body frame 2 provided with R so as to be able to move up and down freely,
The machine frame 2 is provided with a threshing device 4 for threshing the harvested culm from the reaping unit 3 and a boarding operation unit 5.

The engine E mounted on the body frame 2
As shown in FIG. 2, the transmission system from the transmission to the traveling devices 1L and 1R includes a hydrostatic continuously variable transmission 7 which is a main transmission and which can be switched between forward and backward, and a sub-transmission 8 which is a three-stage switching type.
And the turning transmission mechanism 9 are provided in the order described. Note that a manual transmission operation lever 7 </ b> L for performing a shift operation of the continuously variable transmission 7 is provided in the boarding operation unit 5.

The continuously variable transmission 7 includes traveling devices 1L, 1
The output shaft 7A is attached to the transmission case 11 that supports the axles 10L and 10R of the R. Sub-transmission 8 and turning transmission mechanism 9
Is installed in the transmission case 11. An intermediate transmission shaft 14 to which power is transmitted from an output shaft 7A of the continuously variable transmission 7 via a pair of gears 12 and 13 is supported by the transmission case 11 with one end protruding outside. A cutting output pulley 15 for transmitting power to the cutting unit 3 is mounted on an outer end of the intermediate transmission shaft 14, and the intermediate transmission shaft 14 and the cutting output pulley 15 are mounted on the intermediate transmission shaft 14.
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 therebetween.

The power of the intermediate transmission shaft 14 is transmitted to the input shaft 8A of the auxiliary transmission 8 via a pair of gears 17, 18, so that the power is transmitted 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 are interposed with three transmission systems with different transmission ratios from each other. By selecting and using it, a three-stage speed change is performed.

The transmission system for low-speed transmission includes the input shaft 8
A, the first transmission gear G1 is mounted so as to rotate integrally therewith, and the first passive gear g1, which meshes with and interlocks with the first transmission gear G1, is mounted on the output shaft 8B so as to be rotatable with respect to the output shaft 8B. Between the first passive gear g1 and the output shaft 8B, there is provided a wet multiple disc type first hydraulic clutch C1 for intermittently transmitting power from the first passive gear g1 to the output shaft 8B.

The transmission system for medium-speed transmission includes the input shaft 8
A, the second transmission gear G2 is mounted so as to rotate integrally therewith, and the output shaft 8B is mounted with a second passive gear g2 which meshes with and works with the second transmission gear G2 so as to be rotatable with respect to the output shaft 8B. Between the second passive gear g2 and the output shaft 8B, there is provided a wet-type multi-plate type second hydraulic clutch C2 for interrupting transmission from the second passive gear g2 to the output shaft 8B.

The transmission system for high-speed transmission includes the input shaft 8
A, a third transmission gear G3 is mounted on the output shaft 8B so as to rotate integrally therewith, and a third passive gear g3 meshing with the third transmission gear G3 is mounted on the output shaft 8B so as to be rotatable with respect to the output shaft 8B. A wet-type multi-plate type third hydraulic clutch C3 for intermittently transmitting power from the third passive gear g3 to the output shaft 8B is provided between the third passive gear g3 and the output shaft 8B.

The sub-transmission 8 is provided in the <1> first
The first hydraulic clutch C1 is supplied with pressure oil to the first hydraulic clutch C1 to switch the first hydraulic clutch C1 to the engaged state.
By draining 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 low speed transmission transmission system is switched to the transmission state. In the transmission state (falling speed), <2> the second hydraulic clutch C2 is supplied with pressure oil to switch the second hydraulic clutch C2 to the engaged state, and the first hydraulic clutch C1 and the third hydraulic clutch C2 are switched to the engaged state.
By switching the first and third hydraulic clutches C1 and C3 to the clutch disengaged state by draining oil from the hydraulic clutch C3, the medium speed transmission state (standard speed) in which only the transmission system for medium speed transmission is switched to the transmission state. ), And <3> supply pressure oil to the third hydraulic clutch C3 to switch the third hydraulic clutch C3 to the clutch engaged state, and to discharge from the first hydraulic clutch C1 and the second hydraulic clutch C2. By switching the first and second hydraulic clutches C1 and C2 to the clutch disengaged state after oiling, a high-speed transmission state (traveling speed for movement) is achieved 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 established in which the entire transmission system is switched to the non-transmission state.

As the shift operation means of the subtransmission 8, an electromagnetic control valve for the first, second and third hydraulic clutches C1, C2, C is provided in a control device as will be described later. Control.

As shown in FIG. 2, a wet multi-plate parking brake 19 for stopping the traveling devices 1L and 1R by applying a brake to the output shaft 8B is provided.
Is configured to perform a braking action by the biasing force of the interior, and, when the hydraulic pump P is operated to supply the pressurized oil, the braking operation is performed by extending the operation against the biasing force of the spring. It is provided in a negative type to be released, and is configured to automatically return to the braking state when the engine stops in the middle of a slope or the like.

Next, the turning transmission mechanism 9 will be described with reference to FIG. Output shaft 8B of the auxiliary transmission 8
A forward transmission transmission gear 33 is mounted in an integrally rotating state, and meshes with the forward transmission transmission gear 33 on a shift shaft 31 rotatably supported by the transmission case 11. The gear 34 is mounted in an integrally rotating state. The shift shaft 31 further includes a pair of left and right steering passive gears 35L and 35R, and the axle 10
A pair of left and right shift gears 39L, 39R, which are always engaged with and interlock with the wheel bearing dynamic gears 36L, 36R mounted so as to rotate integrally with the L, 10R, respectively, are rotatably mounted. The left and right shift gears 39L, 39R
Of the left and right wheel bearing dynamic gears 36 by the movement of the
L, 36R are meshing type straight-running clutches 37L, 37
R interlocking with the passive transmission gear 34 for forward rotation
The state is freely switchable between a state and a second state interlocked with the passive steering gears 35L, 35R via the meshing type steering clutches 38L, 38R.

A deceleration / reverse braking shaft 40 is rotatably supported by the transmission case 11.
The transmission transmission gears 41L and 41R for equally transmitting the rotation of the rotation to the passive passive gears 35L and 35R are mounted on the reduction / reverse braking shaft 40 so as to rotate integrally with the transmission passive gears 35L and 35R. A forward rotation passive gear 43, which meshes with a transmission gear unit 42 integrally formed with the gear 34 and in which the rotation of the forward rotation transmission passive gear 34 is reduced and transmitted, is rotatably mounted on the speed reduction / reverse rotation braking shaft 40. I have. Then, between the forward passive gear 43 and the deceleration / reverse braking shaft 40, a spring is operated via a spring in a clutch disengaged state in which transmission from the forward / reverse passive gear 43 to the deceleration / reverse braking shaft 40 is cut off when the supply of hydraulic oil is stopped. A wet multi-plate hydraulic clutch 45 for gentle turning is provided which is urged and switches to a clutch-engaged state in which transmission is performed against the urging force with the supply of pressure oil. In other words, by operating the hydraulic clutch 45 to engage the clutch, the rotation of the forward transmission passive gear 34 is transmitted to the transmission gear 42.
-Forward rotation passive gear 43-Reduction gearing 45-Reduction / reverse rotation braking shaft 40-Steering transmission gears 41L, 41R-Steering passive gears 35L, 35R to transmit the vehicle bearing dynamic gears 36L,
36R is configured to be synchronously decelerated.

A reverse transmission passive gear 47 meshing with and interlocking with a reverse transmission transmission gear 46 mounted integrally with the output shaft 8B of the subtransmission 8 is rotatable about the deceleration reverse rotation braking shaft 40. A spring is mounted between the reverse transmission passive gear 47 and the deceleration / reverse braking shaft 40 in a clutch disengaged state in which the transmission from the reverse transmission passive gear 47 to the reduction / reverse braking shaft 40 is cut off when the supply of hydraulic oil is stopped. A wet multi-plate hydraulic clutch 49 for reverse rotation is provided, which is urged through the clutch and switches to a clutch-engaged state in which transmission is performed against the urging force when the pressure oil is supplied. In other words, by operating the hydraulic clutch 49 to engage the clutch, the rotation of the transmission gear 46 for reverse transmission is controlled by the passive gear 47 for reverse transmission, the reverse clutch 49, the reduction reverse rotation brake shaft 40, and the transmission gear 4 for steering.
1L, 41R and the passive steering gears 35L, 35R are transmitted to synchronously reversely drive the wheel bearing dynamic gears 36L, 36R.

Also, the deceleration reverse rotation shaft 4
A wet multi-plate type braking hydraulic brake 50 which is urged through a spring in a clutch disengaged state for braking 0 and reversibly brakes the deceleration / reverse rotation braking shaft 40 against the urging force due to the supply of pressure oil. Is provided. In other words, the braking operation of the hydraulic brake 50 causes the deceleration reverse rotation braking shaft 40
-Steering transmission gears 41L, 41R-Steering passive gear 35
L, 35R to be transmitted to the wheel bearing dynamic gears 36L, 36R.
Is configured to be braked.

That is, the turning transmission mechanism 9 <1> causes the rotation of the forward transmission passive gear 34 to rotate via the both shift gears 39L and 39R when the linear clutches 37L and 37R are both engaged. Gear 36L,
36R, the right and left traveling devices 1L and 1R are driven at a constant speed in a straight traveling state. <2> Steering clutch 38
A non-drive turning state in which the turning side of the left and right traveling devices 1L, 1R is turned off when the driving of the turning side of the left and right traveling devices 1L, 1R is stopped, <3> Steering clutch 38L, 38
The turning-side traveling device 1L or 1R of the passive steering gears 35L and 35R is driven by engaging the turning-side one of the R's with the clutch operation and operating the gentle turning hydraulic clutch 45 with the clutch-engaging operation. Thus, of the left and right traveling devices 1L and 1R, the driving speed of the one on the turning side is made lower than the driving speed of the one on the outside of the turning to perform a gentle turning. <4> Turning of the steering clutches 38L and 38R While the one on the side is engaged with the clutch,
When the braking hydraulic brake 50 is operated, the traveling device 1L or 1R inside the turning is braked and stopped via the steering passive gear 35L or 35R to perform the pivot turning, <5>. Of the steering clutches 38L, 38R, the one on the turning side is engaged with the clutch,
The left and right traveling devices 1L, 1R are driven by driving the reverse rotation hydraulic clutch 49 to engage the clutch, thereby driving the traveling device 1L or 1R inside the turning with the turning inside of the steering passive gears 35L, 35R. It is configured to be able to perform a switching operation in each of a super-spinning turning state in which the one inside the turning is reversely driven to perform a super-spinning turning.

As an operating means of the turning transmission mechanism 9, FIG.
As shown in the figure, the shift gears 39L and 39R are respectively set at the positions where the linear clutches 37L and 37R are engaged.
A pair of left and right springs 52 biased to move via L and 51R
L, 52R and the shift gears 39L, 3 against the urging force of the springs 52L, 52R due to the extension operation with the supply of the pressure oil.
A pair of left and right steering cylinders 53L, 53R for moving each of the 9Rs via the arms 51L, 51R at positions where the steering clutches 38L, 38R are engaged, and pressurized oil is supplied to the left and right steering cylinders 53L, 53R. A pair of left and right electromagnetically operated directional changeover valves 56L and 56R that can be switched between a state in which oil is supplied and a state in which oil is drained are provided.

Further, the left and right steering cylinders 53L, 53
When any of R is in the extension operation state, the hydraulic oil supplied from the steering cylinders 53L, 53R via the oil passage 54 is separately supplied to the hydraulic clutches 45, 49 and the hydraulic brake 50. A steering control valve 55 that switches between a supply stop state and a pressure oil supply state is provided, and a deceleration state supplied to the hydraulic clutch 45 for gentle turning, a reverse rotation state supplied to the hydraulic clutch 49 for reverse rotation, and a hydraulic pressure for braking Brake 5
It is configured to be freely switchable to a braking state in which the pressure is supplied to 0, and the pressure can be adjusted by a pressure adjusting valve 57 interposed in the pressure oil supply path.

The pressure regulating valve 57 is constituted by an electromagnetic proportional pressure control valve, and switches a spool, which is urged to return to the oil discharge side by a spring, to a pressure oil supply side by energizing an electromagnetic solenoid. In addition, by changing and adjusting the supply current to the solenoid, the position of the spool is changed and the hydraulic pressure of the working oil can be changed and adjusted. If the supply current is set to “0”, the supply of the hydraulic oil to each of the hydraulic clutches 45 and 49 and the hydraulic brake 50 can be stopped to set the oil discharge state.

Each of the direction switching valves 56L, 56R and the steering control valve 55 is operated by a turning operation lever 58 as a turning operation tool provided in the boarding operation section 5, and
The control device 60 using the microcomputer performs a switching operation based on the operation of the mode setting device 62. More specifically, the turning mode is set in advance by the operator using the mode setting device 62, and a potentiometer 61 is provided at the swing fulcrum of the turning operation lever 58 as operation amount detecting means for detecting the operation amount. The control device 60 determines the operation position of the turning operation lever 58 based on the detection information, and switches each of the valves in accordance with the turning mode preset by the mode setting device 62. The mode setting unit 62 is configured to select and set one of three modes of “slow turning”, “spin turning”, and “super turning”.
As shown in FIG. 4, as the turning operation lever 58 swings in the left or right direction from the straight traveling command position TS, the first operation area (R1, L1) and the second operation area (R2, L2).
(These correspond to the turning operation area) so that the turning operation lever 58 can be freely switched.
The control device 60 executes the following control in accordance with swinging (turning operation) from the straight-moving command position TS in the left or right direction.

That is, when the turning operation lever 58 is at the straight-moving command position TS, the control device 60 immediately commands the straight running condition. Then, the moving operation amount of the turning operation lever 58 from the straight travel command position TS exceeds a set value (the dead band set as the straight travel command position), and the first operation range (R1, L
As soon as the operation is performed in 1) and a command to switch from the straight running state to the turning state is issued, the state is switched to the non-drive turning state as the first turning operation state in which the turning force is small. . And, the turning operation lever 58
Is operated in the second operation range (R2, L2) for a set time or longer (that is, with a predetermined delay time with respect to the lever operation), the turning force is higher than in the first turning operation state. It is configured to be switched to the large second turning operation state. The second turning operation state is a state set by the mode setting unit 62 among a pivot turning state, a gentle turning state, and a super turning state. In addition, the control device 60 is configured to change and set the set time so that the shorter the moving operation amount of the turning operation lever 58 in the second operation range (R2, L2), the shorter the time.

Next, the turning control operation of the control device will be described based on the control flowchart shown in FIG.
The mode setting by the mode setting unit 62 must be set in advance by the operator according to the work situation at that time.
If the turning operation lever 58 is at the straight-moving command position TS (that is, if the turning operation is not performed), a straight running state is set (steps 1 and 2). That is, the two-way switching valves 56L and 56R are switched to the oil discharging state, and the pressure control valve 57 is switched to the oil discharging state. Swing operation lever 5
When the operation lever 8 is operated in the first operation range (L1 or R1) (that is, when the moving operation amount of the turning operation lever 58 exceeds the dead band set as the straight ahead command position), the non-drive turning state is set. (Steps 3 and 4). That is, the direction switching valve (56L or 56R) on either the left or right side is switched to the pressure oil supply state, and the pressure control valve 57 is maintained in the oil discharge state. When the turning operation lever 58 is operated in the second operation area (L2 or R2), the amount of movement of the lever in the operation area (L2 or R2) is read. Set the set time (delay time) so that the time is reached (steps 5, 6,
7). Then, the turning operation lever 58 is moved to the second operation range (L2
Or, after the set time has elapsed after the operation of R2), the turning mode set by the mode setting device 62 is determined, and the turning operation is executed according to the set mode (steps 8 and 9). If the mode is set to the "slow turning" mode, the mode is switched to the gentle turning state (step 10). That is, the direction switching valve (56L or 56R) on the side selected either left or right is maintained in the pressure oil supply state, and the hydraulic clutch 4 for gentle turning is provided.
The steering control valve 55 and the pressure control valve 57 are switched so that 5 is in the pressure oil supply state. If it is set to the "pivot turning" mode, the mode is switched to the pivot turning state (step 11). In other words, the direction switching valve (56L or 56R) on either the left or right side is maintained in the pressure oil supply state, and the steering control valve 55 is set so that the pivot brake 50 is in the pressure oil supply state. And the pressure control valve 57 is switched. If the mode is set to the "super turning" mode, it is switched to the super turning state (step 12). That is, the direction switching valve (56L or 56R) on the side selected either left or right
Is maintained in the pressure oil supply state, and the steering control valve 55 and the pressure adjustment valve 57 are switched so that the hydraulic clutch 49 for turning the super-revolution turns to the pressure oil supply state. When the turning operation of the turning operation lever 58 is completed, the operation returns, and the turning operation lever 58 returns to the straight traveling command position TS and returns to the straight traveling state (step 13). In any one of the above-mentioned "slow turn", "spin turn", and "super turn", for example, as the moving operation amount of the turning operation lever increases, the hydraulic operating force is gradually increased. The operation of the pressure adjusting valve 57 is controlled so that the turning operation force can be gradually increased according to the lever operation angle.

Therefore, the directional control valves 56R, 56L,
The hydraulic operating mechanism including the steering control valve 55, the pressure adjusting valve 57, the hydraulic pump P, and the like, and the turning transmission mechanism 9 constitute turning operation means, and the control device 60 controls the operation of the turning operation means. Control means will be configured.

[Another Embodiment] (1) In the above embodiment, the change is adjusted so that the set time (delay time) becomes shorter as the moving operation amount becomes larger. However, the present invention is not limited to such a structure. Alternatively, the set time may always be set to a fixed time.

(2) In the above embodiment, the first turning operation state is the "non-drive turning state", and the second turning operation state is the slow turning state, the pivot turning state, and the super turning state. Although the configuration configured to switch to the selected configuration is shown, the invention is not limited to such a configuration, and the first rotation operation state may be any one of the above-described respective rotation states, and may be a rotation state on the small rotation force side. A turning state having a larger turning force may be set as the two turning operation states.

(3) In the above embodiment, the second turning operation state is configured to be switched to one selected from a gentle turning state, a pivot turning state, and a super turning state. However, instead of such a configuration, the following configuration may be adopted. For example, a configuration that switches to one selected from the above two types. A configuration including only one of the above. The second turning operation state is switched to the gentle turning state, and as the turning operation lever is further moved, the gentle turning state is changed to the pivot turning state, and Alternatively, a configuration may be employed in which a super-spin turn state appears sequentially in a stepwise manner.

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

(5) In the above embodiment, the case where the potentiometer is used as the operation state detecting means for detecting the operation state of the turning operation tool (turning operation lever) has been described.
Instead of such a configuration, a configuration may be provided in which switches for individually detecting that the position has been sequentially switched from the straight travel command position to each of the first operation area and the second operation area to detect the operation state.

(6) In the above embodiment, the turning operation means is configured to electrically switch and control the hydraulic operating mechanism based on the operation state of the turning operation tool. It may be configured to be mechanically linked with a tool to switch to each of the above-mentioned turning states corresponding to the above-mentioned respective operating positions.

The present invention can be applied to traveling transmissions of various working vehicles other than the combine.

[Brief description of the drawings]

FIG. 1 is a side view of a combine.

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

FIG. 3 is a hydraulic circuit diagram

FIG. 4 is a control block diagram.

FIG. 5 is a flowchart of a control operation.

[Explanation of symbols]

 1R, 1L traveling device 58 turning operation tool 60 control means 61 operation amount detection means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Chuki 64, Ishizukita-cho, Sakai City, Osaka Prefecture Inside Kubota Sakai Plant (72) Inventor Tetsuya Nakashima 64, Ishizukitacho, Sakai City, Osaka Prefecture Kubota Sakai Co., Ltd. F-term in the factory (reference)

Claims (3)

[Claims] 1. A turning operation in which a driving state of a pair of left and right traveling devices can be freely switched between a straight traveling state, a first turning operation state having a small turning force, and a second turning operation state having a larger turning force. Operating means, a turning operation tool that can be switched between a straight-moving command position for commanding straight running, and a turning command position for commanding switching to a turning state, and control means for controlling operation of the turning operation means are provided. The turning control device for a work vehicle, wherein the control means controls the operation of the turning operation means so that the turning operation tool is immediately switched to the straight running state when the turning operation tool is switched to the straight driving command position. When the turning operation tool is switched to the turning command position, the state immediately switches to the first turning operation state, and when the switching command state to the turning command position continues for a set time or more. Configured work vehicle turn control system to control the operation of the swing operation means to switch to the second turning operation state. The turning operation tool is provided so as to be movable over a predetermined movement width at the turning command position, and an operation amount detecting means for detecting a moving operation amount of the turning operation tool toward the turning side at the turning command position is provided. 2. The work according to claim 1, wherein the control unit is configured to change and set the set time so that the shorter the moving operation amount detected by the operation amount detecting unit is, the shorter the time becomes. Car turning control device. 3. The traveling device located on a turning side of the pair of left and right traveling devices enters a free idling state, and the traveling device located on the opposite side, as the first turning operation state. The driving device is configured to switch to a non-drive turning state in which the driving device is in a driving state, and as the second turning operation state, the traveling device located on the turning side is in a transmission stopped state and is braked, and the traveling device is located on the opposite side. Is a driving turn state, the traveling device located on the turning side is a gentle turning state in which the traveling device is driven at a lower speed than the other traveling device,
3. The turning control device for a work vehicle according to claim 1, wherein the left and right traveling devices are configured to switch to one of a super pivot turning state in which the right and left traveling devices are driven in opposite directions.