JP2000104819A - Running transmission of working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the shock to an operator to the utmost in response to the gear shift by a sub-transmission. SOLUTION: In the running transmission of a working car provided with a main transmission and sub-transmission on the transmission mechanism for running, a speed governing control means 101 for carrying out the speed regulation and control for speed-changing the main transmission is provided so that the sub-transmission becomes the running speed before the speed change of the sub-transmission or the running speed near to that, in accordance with the speed change of the sub-transmission.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling transmission for a working vehicle in which a traveling transmission mechanism is provided with a main transmission and an auxiliary transmission.

[0002]

2. Description of the Related Art In the above-mentioned traveling transmission for workers, conventionally, as a main transmission, a hydraulic type transmission in which a hydraulic pump driven by an engine and a hydraulic motor for driving the traveling device are connected by a closed circuit. The oil flow from the hydraulic pump to the hydraulic motor is provided by providing a pair of left and right step transmissions and switching an electromagnetically operated shift control valve based on a command from an auxiliary transmission switch, which is another operation means different from the operation for the main transmission. Is provided with a sub-transmission device that can be switched to a two-stage high-low gear state by changing the gear to two high-low stages, and the gear state is alternately switched between a high-speed state and a low-speed state every time a shift is commanded by the sub-transmission switch. There has been a device configured as described above (for example, see Japanese Patent Application Laid-Open No. 9-76782).

In other words, a conventional traveling transmission for a working vehicle is
By changing the speed by the auxiliary transmission without changing the shift position by the main transmission, the traveling speed of the work vehicle can be quickly returned to the original operation speed,
The work could be performed efficiently.

[0004]

However, in the prior art, when the speed change operation of the auxiliary transmission is performed by the auxiliary speed change switch, the traveling speed of the work vehicle rapidly changes with the speed change operation. In some cases, the driver's posture becomes unstable, giving anxiety or discomfort. In addition, when the speed suddenly changes as described above, particularly when the speed increases, the driving load on the working device may suddenly increase and the work may not be performed properly.

The present invention has been made in view of such a point, and an object of the present invention is to minimize a decrease in maneuverability and workability due to a shift operation by a subtransmission. Another object of the present invention is to provide a traveling transmission for a work vehicle.

[0006]

In order to achieve this object, according to the first aspect of the present invention, the traveling speed or the traveling speed of the sub-transmission before the sub-transmission is shifted as the sub-transmission is shifted. There is provided a speed control means for executing speed adjustment control for shifting the speed of the main transmission so that the running speed becomes close to the running speed. Therefore, the speed adjustment control is performed by the speed control unit as the sub-transmission is shifted, so that a sudden change in the traveling speed of the work vehicle due to the shift of the sub-transmission can be prevented, It is possible to minimize the impact on the driver due to the shifting operation by the auxiliary transmission,
In addition, it is possible to suppress a sudden change in the load on the working device and suppress a decrease in workability.

According to the second aspect of the present invention, the auxiliary transmission includes a plurality of hydraulically operated friction transmission mechanisms, and the plurality of friction transmission mechanisms are selectively operated based on a command from the auxiliary transmission command means. By switching to the operating state, the state can be switched to any of a plurality of shift operation states. Therefore, the speed of the auxiliary transmission can be shifted by an easy operation of merely switching the operation states of the plurality of friction transmission mechanisms. Further, by performing the speed adjustment control, the auxiliary transmission can be shifted by switching the operation states of the friction transmission mechanisms. It is possible to prevent the traveling speed of the work vehicle from suddenly changing with the shift of the transmission.

According to the third aspect of the present invention, the sub-transmission is provided with a mowing work section for mowing the culm to be planted while traveling, and the auxiliary transmission device is in a normal working shift state for mowing the upright cereal culm. And a speed change control means for changing the speed of the auxiliary transmission from the low speed operation speed change state to the normal operation speed change state during the harvesting operation. The speed adjustment control is executed only when the speed adjustment is performed. That is, for example, in a combine equipped with a cutting work unit, when cutting a grain culm to be planted in the cutting work unit, depending on whether the grain culm is an upright grain culm or a lodging grain culm, the shift position of the main transmission is not changed. In addition, by shifting the speed change state of the auxiliary transmission to one of the normal work shift state and the low speed work shift state, the mowing work can be performed efficiently. That is, when cutting the lodging grain culm, the speed is shifted to a low-speed work shift state lower than the normal work shift state, so that the work load on the cutting work unit can be reduced, and the harvesting work can be performed as appropriately as possible.

Then, after the sub-transmission is shifted to the low-speed work shift state to perform the harvesting work on the lodging grain, the sub-transmission is shifted from the low-speed work shift state to the normal work shift state. Since the speed adjustment control is executed, it is possible to suppress a sudden increase in the traveling driving load and a work load caused by the reaping work unit due to a rapid increase in the traveling speed, thereby suppressing a decrease in the reaping work performance. It is conceivable that the speed adjustment control is also executed when the subtransmission is shifted from the normal work shift state to the low-speed work shift state, but in this case, the running speed is reduced. Since both the running load and the mowing work load are reduced, it is not necessary to suppress them, and since the speed adjustment control is not performed, the cutting work of the lodging grain can be properly performed at a low speed. is there.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a traveling transmission of a combine according to an embodiment of the present invention; 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 reaper 3 as a reaping operation section for reaping planted grain culms and transporting the culm to the rear is connected to the front of the body frame 2 provided with R so as to be able to move up and down freely. A threshing device 4 for threshing a harvested grain culm and a boarding operation unit 5 are mounted. A stock sensor S0 that is turned on by contacting with the stock of the harvested grain culm is provided at the transport start end portion where the harvested grain culm is transported to the rear side of the machine while changing to the sideways posture. .

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 a transmission case 11 having a steering device 9. The continuously variable transmission 7 is provided with an electric motor M
The gearshift operation is performed by the electric motor M, and the manual gearshift operation by the gearshift operation lever 7L is prioritized to the gearshift operation by the electric motor M. In order to achieve this, the electric motor M is linked via a frictional transmission mechanism DM in a linking path between the shift operation lever 7L and the continuously variable transmission 7.

Further, the engine E, the threshing device 4 and the reaping device 3 are operatively connected to each other via a belt-tensioning threshing clutch DK and a reaping clutch KK, thereby manually turning on and off the threshing clutch DK and the reaping clutch KK, respectively. The threshing clutch lever DR and the reaping clutch lever KR are provided in the boarding operation unit 5. A rotation speed detection sensor S for detecting the rotation speed of the engine E
1 and a vehicle speed sensor S2 for detecting a vehicle speed based on the output speed of the continuously variable transmission 7 transmitted to the input shaft of the transmission case 11.

As shown in FIG. 3, the continuously variable transmission 7 includes axles 10L, 10R of traveling devices 1L, 1R, respectively.
Is mounted in a state in which the output shaft 7A is inserted into the transmission case 11 that supports the output shaft 7A. The auxiliary transmission 8 and the steering device 9 are housed 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 provided between the intermediate transmission shaft 14 and the cutting output pulley 15. One-way clutch 1 that transmits only forward rotation of shaft 14 to cutting output pulley 15
6 are interposed.

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 and 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.

As shown in FIG. 4, each of the first, second and third hydraulic clutches C1, C2, C3 supplies pressure oil to an oil chamber r via each hydraulic circuit L1, L2, L3. Along with the supply, the clutch is switched to a clutch-engaging state in which transmission is performed against the biasing force of the spring PB, and the transmission is cut off by the biasing force of the spring PB in accordance with the discharge of oil from the oil chamber r. This is a positive hydraulic clutch that switches.

That is, the auxiliary transmission 8 includes a plurality of hydraulically operated friction transmission mechanisms such as the first, second and third hydraulic clutches C1, C2, C3 and the respective hydraulic circuits L1, L2, L3. It is provided with.

The sub-transmission 8 is provided in the <1> first
The hydraulic oil is supplied to the hydraulic clutch C1 to switch the first hydraulic clutch C1 to the engaged state, and
Of the second and third hydraulic clutches C2 and C3.
Is switched to the clutch disengaged state, whereby only the transmission system for low-speed transmission is switched to the transmission state, which results in a low-speed transmission state (lower speed) as a low-speed work shift state, and <2>
Supplying hydraulic oil to the second hydraulic clutch C2 to switch the second hydraulic clutch C2 to the engaged state; and
First hydraulic clutch C1 and third hydraulic clutch C3
From the first and third hydraulic clutches C1,
By switching C3 to the clutch disengaged state, a medium speed transmission state (standard speed) is obtained as a shift state for normal work in which 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 to the engaged state,
Further, only the transmission system for high-speed transmission is transmitted by draining oil from the first hydraulic clutch C1 and the second hydraulic clutch C2 and switching the first and second hydraulic clutches C1 and C2 to the clutch disengaged state. High-speed transmission state (moving traveling speed) as a shifting state for shifting to state
<4> Oil is drained 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, C2,
By switching C3 to the clutch disengaged state, a neutral state is established in which the entire transmission system is switched to the non-transmission state.

The low-speed transmission state is a transmission state for performing a cutting operation at a low speed, which is used when, for example, a grain stem to be cut is lying down. The medium-speed transmission state is a transmission state for executing a mowing operation at a medium speed (standard speed) used when the culm to be cut is upright. The high-speed transmission state is, for example, a transmission state used when the vehicle travels on a road at a high speed in a non-working state. The neutral state is used, for example, in a case where the mowing unit 3 is driven to perform maintenance work in a state in which the machine body traveling is stopped.

As shown in FIG. 5, the auxiliary transmission 8 is
Any one of the hydraulic clutches C1, C2, C3 is provided between the hydraulic pump P and each of the hydraulic circuits L1, L2, L3 for the first, second, and third hydraulic clutches C1, C2, C3. A speed change control valve B1 for supplying pressure oil to the other and switching to a state of discharging oil from the remaining hydraulic clutches;
A pressure oil supply state in which the pressure oil from the hydraulic pump P is supplied to the shift control valve B1, and a drainage state in which the supply of the pressure oil to the shift control valve B1 is stopped to drain the oil from the hydraulic clutches C1, C2, and C3. The switchable neutral switching valve B2 is interposed.

Here, the shift control valve B1 is a three-position switching type solenoid valve, and has solenoids sb1 and sb2 for switching operation on the left and right. When both of the solenoids sb1 and sb2 are not energized, the oil path switching spool is provided with a spring so as to supply pressure oil to the hydraulic circuit of the second hydraulic clutch C2 (for standard speed). When the solenoid sb1 on the left side is energized while the solenoid sb1 on the left side is energized, the state is switched to a state in which pressure oil is supplied to the first hydraulic clutch C1 (for the falling speed), 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 urged 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.

Accordingly, the transmission control valve B1 and the neutral switching valve B2 constitute the electrically operated switching means KS, and a state in which no driving power is supplied thereto, for example, a disconnection of the electric wiring, When an electrical system failure occurs, such as an abnormality in the electrical control operation of the control device described later, the gear shifts back to the medium speed transmission state (standard speed) as the shift state for normal work, which is the set shift state. It is configured to be energized, so that even if such an electrical system failure occurs, it is possible to continue the mowing work at the normal running speed for mowing work thereafter.

The control device 60 is provided with a microcomputer. As shown in FIG. 6, the control device 60 utilizes the stock sensor S0, the rotation speed detection sensor S1, the vehicle speed sensor S2, and the threshing control. The engine load is maintained in the proper load range based on the detection information of the threshing switch SW1 and the cutting switch SW2 that are turned on in accordance with the on-operation of the clutch lever DR and the cutting clutch lever KR so that the engine load does not exceed the set upper limit vehicle speed. Speed control means 1 for executing vehicle speed control for controlling the traveling speed of the combine
00 is configured. This vehicle speed control is executed only when the vehicle speed auto switch SW3 for instructing whether or not to execute the vehicle speed control provided in the boarding driving unit 5 is turned on.

That is, the rotation speed of the engine E is
Since the load decreases when the load of the engine E increases and increases when the load on the engine E decreases, the load on the engine E is detected based on the detection information of the rotation speed detection sensor S1. And
The engine speed RX (rpm) when the stock sensor S0 and the threshing switch SW1 are on and the vehicle speed is 0.1 m / sec or more is stored as the reference speed RS. When the above condition is satisfied, if an engine speed RX higher than the stored reference speed RS is detected, the reference speed RS is updated to the detected value and the engine speed from the reference speed RS is updated. Reduction amount of rotation speed RX (rpm)
Is detected as an engine load. When the engine load deviates from the appropriate load range to the load increasing side, the electric motor M is operated so as to decelerate. When the engine load deviates from the appropriate load range to the load decreasing side, the vehicle speed does not exceed the upper limit vehicle speed. The electric motor M is operated so as to increase the speed.

As shown in FIGS. 6 and 7, the control device 60 includes a sub-shift instructing means comprising a push button type first switch SU and a second switch SD in the grip operating portion of the shift operating lever 7L. , And is configured to control the operation of the first and second electromagnetic control valves B1 and B2 based on information input from the switches SU and SD.

The control device 60 is configured to switch the neutral switching valve B2 to the oil discharging state based on the operation of each of the switches, to set the neutral switching valve B2 to the hydraulic oil supply state, and to set the transmission control valve B1 to the first hydraulic pressure. A low-speed transmission state in which pressure oil is supplied only to the clutch C1, a neutral switching valve B2 in which pressure oil is supplied, and the shift control valve B1 is a medium-speed transmission state in which pressure oil is supplied only to the second hydraulic clutch C2, a neutral switching valve Each of the valves is controlled such that B2 is in a pressure oil supply state and the shift control valve B1 is switched to a high-speed transmission state in which pressure oil is supplied only to the third hydraulic clutch C3.

As a specific switching operation, each 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
Each time D is turned on, the control valves B1 and B2 are sequentially switched to the low speed side. Specifically, FIG.
As shown in FIG. 5, when the first switch SU is turned on when the subtransmission 8 is in the neutral state N, the first transmission switch F1 is in the low-speed transmission state F1.
When the first switch SU is turned on while in the middle speed transmission state F2, the second switch SD is turned on when the first switch SU is turned on in the middle speed transmission state F2. Medium speed transmission state F2
And the second switch S when in the middle speed transmission state F2.
When D is turned on, the state becomes the low-speed transmission state F1, and when the second switch SD is turned on while in the low-speed transmission state F1, the state becomes the neutral state N. Note that, at the beginning of operation when power is supplied to the control device 60, the shift control valve B1 is in the medium speed transmission state, and the neutral switching valve B2 is initially set to the pressure oil supply state.

When a mowing operation is performed in a field or the like, the mowing traveling is executed mainly in a state set to the medium-speed transmission state F2. Further, when the culm to be cut is lying down, the work is switched to the low-speed transmission state F1 and work is performed at a low speed, but the mutual transmission between the medium-speed transmission state F2 and the low-speed transmission state F1 is performed. The transmission state switching operation can be appropriately performed even during work traveling. However, switching from the low-speed transmission state F1 to the neutral state N and switching from the medium-speed transmission state F2 to the high-speed transmission state F3 may cause inconvenience due to a sudden change in vehicle speed. The control device 60 controls the switching operation state so that the operation can be performed only when the vehicle body is stopped.

The control device 60 shifts the continuously variable transmission 7 so that the running speed before the speed change of the subtransmission device 8 or the running speed close to the running speed before the speed change of the subtransmission device 8 is accompanied by the speed change of the subtransmission device 8. It is configured to execute speed adjustment control. More specifically, when the speed change state of the auxiliary transmission 8 is operated by the auxiliary transmission operating section 62, the auxiliary transmission 8
The electric motor M is operated so as to reach the traveling speed based on the detection information of the vehicle speed sensor S2 before the vehicle is shifted. That is, the electric motor M and the control device 60 are configured as the speed control means 101.

The speed adjustment control is executed only when the subtransmission 8 is shifted from the low-speed operation shift state to the normal operation shift state during the combine harvesting operation. . That is, the auxiliary transmission 8
Only when the transmission state is changed from the low-speed transmission state to the medium-speed transmission state, based on the detection information of the vehicle speed sensor S2 before the auxiliary transmission 8 is shifted, the electric motor is driven to the traveling speed. Activate M.

Therefore, by using the control device 60, the traveling control of the combine of the vehicle speed control and the speed adjustment control is executed, so that the harvesting operation can be performed efficiently. Also,
By executing the speed adjustment control, even when the speed of the auxiliary transmission 8 is shifted, the traveling speed of the combine does not suddenly change, and the impact on the driver can be suppressed. It can be done smoothly.

As shown in FIG. 3, the output shaft 8B
Is provided with a parking brake 19 of a wet-type multi-plate type for stopping and holding the traveling devices 1L and 1R by applying a brake to the vehicle, and this parking brake 19 performs a braking operation by the biasing force of a built-in spring 19b as shown in FIG. As well as
Along with the operation of the hydraulic pump P and the supply of the pressure oil, a negative brake cylinder 19A is provided which extends to release the braking state against the urging force of the spring 19b,
If the engine stops on a slope,
It is configured to automatically return to the braking state.

Next, the steering device 9 will be described with reference to FIG. A transmission gear 33 for normal rotation transmission is mounted on the output shaft 8B of the auxiliary transmission 8 in an integrally rotating state, and the transmission gear 33 for normal rotation transmission is mounted on the shift shaft 31 rotatably supported by the transmission case 11. The forward rotation transmission passive gear 34 that meshes with and is mounted integrally with the transmission. Further, the shift shaft 31 has a pair of left and right steering passive gears 35L, 35R and the axles 10L, 10R.
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 to rotate integrally with each other, are rotatably mounted.
The movement of the left and right shift gears 39L, 39R in the axial direction causes the left and right wheel bearing dynamic gears 36L, 36R.
However, the first state is interlocked with the forward transmission passive gear 34 via the engagement type straight traveling clutches 37L, 37R, and the steering passive gears 35L, 35R via the engagement type steering clutches 38L, 38R. It is configured to be able to switch to the interlocked second state.

A deceleration / reverse braking shaft 40 is rotatably supported by the transmission case 11, and the deceleration / reverse braking shaft 4
Transmission transmission gears 41L, 41 for reducing and transmitting the rotation of 0 to the respective steering passive gears 35L, 35R equally.
R is mounted so as to rotate integrally with the deceleration / reverse rotation braking shaft 40, and meshes with a transmission gear unit 42 integrally formed with the forward rotation transmission passive gear 34 to rotate the forward rotation transmission passive gear 34. The forward rotation passive gear 43 that is transmitted at a reduced speed is
It is rotatably mounted on the deceleration reverse rotation shaft 40.
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 deceleration wet-type multi-plate type hydraulic clutch 45 is provided which is urged 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 45 to engage the clutch, the rotation of the passive transmission gear 34 for forward rotation transmission is transmitted to the transmission gear unit 4.
2, the forward passive gear 43, the reduction clutch 45, the reduction / reverse rotation braking shaft 40, the steering transmission gears 41L, 41R, and the passive steering gears 35L, 35R.
L, 36R are 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 auxiliary transmission 8 is rotatable about the reduction reverse rotation braking shaft 40. Attached between the reverse transmission passive gear 47 and the reduction reverse braking shaft 40, the reverse transmission passive gear 47 is moved from the reduction transmission reverse braking shaft
A wet multi-plate hydraulic clutch 49 for reverse rotation, which is urged through a spring in a clutch disengaged state to cut off transmission to the clutch and switches to a clutch engaged state in which transmission is performed in response to the urging force due to the supply of pressure oil. Is provided. That is, 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 braking shaft 40, the transmission gears 41L, 41R, and the steering. The transmission is transmitted to the passive gears 35L, 35R for use to drive the wheel bearing dynamic gears 36L, 36R synchronously and reversely.

Further, when the supply of the hydraulic oil is stopped, the deceleration / reverse braking shaft 40 is actuated via a spring in a clutch disengaged state for braking the deceleration / reverse rotation braking shaft 40, and the deceleration / reverse braking shaft 40 is pressed against the urging force with the supply of the hydraulic oil. A wet multi-plate type hydraulic brake 50 for reversible braking is provided. In other words, the braking operation of the hydraulic brake 50 causes the deceleration reverse rotation braking shaft 4 to rotate.
0, steering transmission gears 41L, 41R, steering passive gear 3
5L and 35R to transmit the wheel bearing dynamic gears 36L and 36R.
It is configured to brake R.

That is, the steering device 9 controls the rotation of the forward transmission passive gear 34 via both the shift gears 39L and 39R to cause the rotation of the forward drive transmission gear 34 to be performed by the both gears 37L and 37R. 36L, 36R
, The right and left traveling devices 1L, 1R are driven at a constant speed, and <2> the steering clutch 38L,
The non-drive turning state in which the turning side of the left and right traveling devices 1L and 1R is driven to be in a free idling state by turning off the turning side one of the left and right traveling devices 1L and 1R by operating the clutch of the turning clutch 38L. , 38R, the turning-side one is engaged and the deceleration hydraulic clutch 45 is engaged.
Traveling device 1 on the turning side of passive steering gears 35L and 35
By driving the L or 1R, the left and right traveling devices 1
Slow turning state in which the driving speed of the turning side of L and 1R is smaller than the driving speed of the turning outside, and the turning is slow, <4> the turning side of the steering clutches 38L and 38R is engaged. And a braking operation of the braking hydraulic brake 50 to stop the braking of the traveling device 1L or 1R on the inner side of the turning via the steering passive gear 35L or 35R to perform a pivoting state in which the pivoting is performed. <5> The turning clutch of the steering clutches 38L and 38R is operated to be engaged, and the hydraulic clutch 49 for reverse rotation is operated to be engaged.
By driving the traveling device 1L or 1R on the inner side of the turning with the one inside the turning among the passive steering gears 35L and 35R, the one on the inner side of the turning on the left and right traveling devices 1L and 1R is driven to rotate in the reverse direction, and It is configured to be able to perform a switching operation in each of a super-spinning state and a turning state.

As the operating means of the steering device 9, as shown in FIG. 5, the shift gears 39L and 39R are moved to the positions where the linear clutches 37L and 37R are engaged, respectively.
A pair of left and right springs 52L and 52R that move and urge through R
And the springs 52L, 5
A pair of left and right steering cylinders 53L, 53R for moving the shift gears 39L, 39R respectively at the engagement positions of the steering clutches 38L, 38R via the arms 51L, 51R against the urging force of the 2R are provided. A pair of left and right electromagnetically operated directional changeover valves 56L, 56R is provided which can be switched between a state in which pressure oil is supplied to each of the steering cylinders 53L, 53R and a state in which oil is discharged.

Further, left and right steering cylinders 53L, 53
When any one of R is in the extension operation state, the pressure oil supplied from the steering cylinders 53L and 53R via the oil passage 54 is supplied to the deceleration hydraulic clutch 45, and the reverse rotation hydraulic pressure is supplied. An electromagnetically operated steering control valve 55 is provided as oil path switching means for mode switching which can be switched between a reverse rotation state supplied to the clutch 49 and a braking state supplied to the hydraulic brake 50 for braking. The oil passage 54
The pressure for adjusting the hydraulic pressure (that is, the turning force) of the hydraulic oil supplied to each of the hydraulic clutches 45 and 49 and the hydraulic brake 50 based on the operation state of the steering operation lever 58 to be described later. An adjustment valve 57 is provided. The pressure adjusting valve 57 is configured by an electromagnetic proportional pressure control valve, and switches a spool that is urged to return to the oil discharge side by a spring to a pressure oil supply side by energizing an electromagnetic solenoid. 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.

Each of the direction switching valves 56L and 56R, the steering control valve 55, and the pressure adjusting valve 57 is operated based on the operation of a steering operation lever 58 as a turning operation tool provided in the boarding operation section 5. The switching is controlled by the control device 60. More specifically, a potentiometer 61 is provided at the pivot point of the steering operation lever 58 as operation state detecting means for detecting the operation state thereof.
The control device 60 determines the operating position of the steering operation lever 58 based on the detection information, and switches the valves. That is, as shown in FIG. 6, as the steering operation lever 58 swings in the right or left direction from the straight traveling command position TS, the non-drive turning position (R1, L
1), gentle turning position (R2, L2), pivot position (R
3, L3), and the super turning position (R4, L4). The steering operation lever 58 is swung in any one of the left and right directions from the straight movement command position TS. Accordingly, the control device 60 performs control as follows. When the steering lever 58 is located at the straight traveling command position TS, the two-way switching valves 56L and 56R are switched to the oil discharging state and the pressure adjusting valve 57 is switched to the non-operating state (straight traveling state). When the steering operation lever 58 is operated to the non-drive turning position (L1 or R1), 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 adjustment valve 57 is switched. Switch to the non-operation state (non-drive turning state). When the steering operation lever 58 is in the gentle turning position (L2 or R
When operated in 2), the direction switching valve (56L or 56R) on either side selected is switched to the pressure oil supply state, the pressure adjustment valve 57 is switched to the operation state, and the steering control valve 55 is decelerated. (Slow turning state). When the steering operation lever 58 is in the pivot position (L3 or R
When operated in 3), the directional control valve (56L or 56R) on either the left or right side is switched to the pressure oil supply state, the pressure adjustment valve 57 is switched to the operating state, and the steering control valve 55 is switched to the braking state. (The pivot state). When the steering operation lever 58 is operated to the pivot turn position (L4 or R4), 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 adjustment valve 57 is switched. Switch to the operating state,
The steering control valve 55 is switched to the reverse rotation state (super turning state).

Next, the traveling control of the combine will be described with reference to the flowcharts of FIGS. First,
Whether the stock sensor S0 and the threshing switch SW1 are in the ON state, the vehicle speed is 0.1 m / s or more, and the speed change state of the auxiliary transmission device 8 is not the low-speed work shift state, or the vehicle speed control execution condition is satisfied. Is determined, and if the vehicle speed control execution condition is satisfied, the vehicle speed control is executed.

That is, as shown in the flowchart of FIG. 10, the detected engine speed RX is compared with the reference speed RS, and if the detected engine speed RX is larger than the reference speed RS, the detected engine speed RX is determined. The value is updated and stored as the reference rotation speed RS. Note that the initial value of the reference rotation speed RS has been reset to zero. Then, the difference between the reference rotation speed RS and the detected rotation speed RX is determined as the engine load, and if the engine load is not within the appropriate range, the gear change operation is not performed. When the engine load is larger than the appropriate range, a deceleration operation is performed. When the engine load is smaller than the appropriate range, the speed increasing operation is performed only when the detected vehicle speed is lower than the upper limit vehicle speed, and when the detected vehicle speed is higher than the upper limit vehicle speed, the speed change operation is not performed.

If the vehicle speed control execution condition is not satisfied, the state of the subtransmission 8 is switched to the low speed transmission state F1 and the low speed transmission state F1 by the subtransmission operation unit 62 is changed to the medium speed transmission state. If there is a gearshift command to F2, the speed adjustment control is executed until the set time from when the gearshift operation is performed until the running speed is predicted to be stable has elapsed. That is, as shown in the flowchart of FIG. 11, the detected vehicle speed Vs of the vehicle speed sensor S2 immediately before the subtransmission 8 is shifted from the low-speed transmission state F1 to the medium-speed transmission state F2 is read and stored. The transmission 8 is controlled to shift from the low speed transmission state F1 to the medium speed transmission state F2, and the electric motor M is decelerated so that the detected value Vx of the vehicle speed sensor S2 becomes the detected vehicle speed Vs. At this time, the speed change operation of the auxiliary transmission 8 is performed slowly by changing the energization state of the solenoids sb1 and sb2 by, for example, a pulse current and changing the pulse duty ratio as appropriate. It is better to control it. Then, when the set time has elapsed, the execution condition of the vehicle speed control is satisfied, so that the process shifts to the vehicle speed control and the vehicle speed control according to the engine load is executed.

[Other Embodiments] (1) In the above embodiment, when the speed change state of the subtransmission 8 is shifted by the subtransmission operating section 62, the detection information of the vehicle speed sensor S2 before the speed of the subtransmission 8 is changed. On the basis of the,
The speed adjustment control is executed by operating the electric motor M so as to attain the traveling speed. For example, the ultimate traveling speed at which the traveling speed reaches as the auxiliary transmission 8 is shifted is calculated. The speed of the continuously variable transmission 7 is increased or reduced by the obtained traveling speed, and the speed of the continuously variable transmission 7 is changed to the traveling speed before the auxiliary transmission 8 is shifted or to a traveling speed close thereto. Is also good.

(2) In the above-described embodiment, the sub-transmission is configured such that a plurality of hydraulic clutches are selectively switched to the transmission state to obtain a desired transmission state. However, the present invention provides such a configuration. For example, a so-called hydrostatic continuously variable transmission (HST) that includes a hydraulic pump and a hydraulic motor as a main transmission and changes and adjusts a traveling speed by changing a swash plate angle is used. The present invention can also be applied to an auxiliary transmission having a configuration in which the transmission state is switched to a plurality of high and low steps by changing the oil flow rate for each continuously variable transmission by independently providing the traveling device.

(3) In the above embodiment, the speed adjustment control is executed only when the sub-transmission 8 is shifted from the low-speed work shift state to the normal work shift state during the harvesting work of the combine as the work vehicle. However, the speed adjustment control is performed not only when the speed of the auxiliary transmission 8 is shifted from the low-speed operation shift state to the normal operation shift state, but also every time the auxiliary transmission 8 is shifted. It may be.

(4) In the above embodiment, as the operating means for the auxiliary transmission, the shift operation lever 7L of the main transmission is provided with the first switch SU and the second switch SD.
Although the configuration in which the shift state is sequentially switched in accordance with the operation of each switch has been illustrated, the following configuration may be used instead of such a configuration. A configuration in which the first switch SU and the second switch SD are provided at a portion different from the speed change operation lever. As shown in FIG. 12, four operation switches SN, S1, S2, and S3 corresponding to the respective shift states are provided, and each of the operation switches is selectively operated to select the selected shift state ( N, F1, F2, F3). As shown in FIG. 13, the swing operation type auxiliary shift lever 7
0, and the control device 60 switches the valves B1 and B2 so that the lever swing operation angle is detected by the potentiometer type detection sensor 71 and the gears are sequentially switched to the shift states according to the operation angle. Configuration to control.

(5) In the above embodiment, a configuration using a three-position switching type electromagnetic control valve as the electrically operated switching means KS has been exemplified. However, instead of such a configuration, the following configuration is used. Is also good. For example, as shown in FIG. 14, for each of the hydraulic clutches C1, C2, C3, a two-position switching type electromagnetic control valve V1, V2, which can be separately switched between a pressurized oil supply state and a drainage state. V3,
A first hydraulic clutch C1 and a third hydraulic clutch C
The electromagnetic control valves V1 and V3 for the second hydraulic clutch C2 are both urged to return to the oil discharge state and switched to the hydraulic oil supply state by supplying electric power to the solenoid, whereas the electromagnetic control valves V1 and V3 for the second hydraulic clutch C2 The valve V2 is configured to be urged to return to the pressure oil supply state and switch to the oil discharge state by supplying power to the solenoid. Therefore, when the driving power is no longer supplied, only the electromagnetic control valve V2 enters the pressure oil supply state, and is returned to the medium speed transmission state F2.

(6) In the above-described embodiment, a case has been exemplified in which the subtransmission is configured to be switchable between four states of a low-speed transmission state F1, a medium-speed transmission state F2, a high-speed transmission state F3, and a neutral state N. Is not limited to such a configuration, a configuration that switches between two stages of a high-speed state and a low-speed state, a configuration that switches to a three-stage traveling state of high, medium, and low, a configuration that switches to a traveling state of four or more stages, Further, a configuration that switches to various shift states, such as a configuration in which these are combined with a neutral state, may be used.

(7) In the above embodiment, the traveling vehicle of the combine is exemplified as the work vehicle. However, the present invention is not limited to the combine vehicle, but can be applied to other work vehicles such as tractors and construction machines.

[Brief description of the drawings]

FIG. 1 is a side view of a combine.

FIG. 2 is a schematic configuration diagram of a combine.

FIG. 3 is a diagram showing a traveling transmission structure.

FIG. 4 is a vertical cross-sectional front view of the transmission mechanism for sub-transmission.

FIG. 5 is a hydraulic circuit diagram

FIG. 6 is a control block diagram.

FIG. 7 is a diagram showing an auxiliary speed change operation unit.

FIG. 8 is a diagram showing an operation state of the auxiliary transmission.

FIG. 9 is a flowchart showing a control operation.

FIG. 10 is a flowchart showing a control operation of vehicle speed control.

FIG. 11 is a flowchart showing a control operation of speed adjustment control.

FIG. 12 is a control block diagram of another embodiment.

FIG. 13 is a control block diagram of another embodiment.

FIG. 14 is a hydraulic circuit diagram of another embodiment.

[Description of Signs] 3 Cutting part 7 Main transmission device 8 Sub transmission device 62 Sub transmission command means 101 Governing control means C1-3, L1-3 Hydraulically operated friction transmission mechanism

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Koji Yamagata 64 Ishizu-Kitacho, Sakai-shi, Osaka F-term in Kubota Sakai Works (reference) 3D039 AA02 AA04 AA07 AB11 AB22 AC03 AC37 AC40 AC54 AC87 AC89 AD06 AD23 AD43 AD44 AD53

Claims (3)

[Claims] 1. A traveling transmission for a working vehicle in which a traveling transmission mechanism is provided with a main transmission and an auxiliary transmission, wherein the auxiliary transmission is shifted as the auxiliary transmission is shifted. A traveling transmission device for a work vehicle provided with speed control means for executing speed adjustment control for shifting the speed of the main transmission device so that the traveling speed becomes the traveling speed before the transmission is shifted or a traveling speed close thereto. 2. The apparatus according to claim 1, wherein the auxiliary transmission includes a plurality of hydraulically operated friction transmission mechanisms, and the plurality of friction transmission mechanisms are selectively switched to an operating state based on a command from an auxiliary transmission command unit. The traveling transmission device for a working vehicle according to claim 1, wherein the traveling transmission device is configured to be capable of switching to any one of a plurality of shift operation states. 3. A cutting operation unit for cutting a grain culm to be planted while running, wherein the auxiliary transmission device is in a normal work shift state for cutting an upright grain culm, and is also for cutting a lodging grain culm. In the mowing operation, the speed control unit is configured to change the speed of the auxiliary transmission from the low-speed operation shift state to the normal operation shift state. The traveling transmission for a working vehicle according to claim 1 or 2, wherein the traveling transmission is configured to execute the speed adjustment control only.