JP2002255056A - Power transmission control device for working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optionally regulate a turning radius of a vehicle body when a working vehicle comprising a crawler unit regulates a right and left rotation ratio of a transmission mechanism and turns the vehicle body by locking or checking the lock of one crawler according to a state of the ground. SOLUTION: By mounting the transmission mechanism formed by a normal/ reverse rotation switching device and a two-stage planetary gear mechanism in a rear axle case and regulating a clutch cylinder pressure of the normal/ reverse rotation switching device, a clutch for a normal rotation and a clutch for a reverse rotation are let in/out for regulating rotational directions and rotational speeds of the right and left crawlers to optionally regulate the turning radius of the vehicle body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission control device for a work vehicle, and more particularly to a power transmission control device for an agricultural, construction, or transportation work vehicle having a crawler type traveling device. is there.

[0002]

2. Description of the Related Art Conventionally, this type of working vehicle has been disclosed in
As described in Japanese Patent Publication No. 235171, a transmission case is known in which a transmission case is provided at a rear portion of a vehicle body and a crawler-type traveling device is supported on left and right sides of the transmission case. In the work vehicle, the steering handle and the left and right brake devices are connected via a mechanical interlocking mechanism including a link mechanism and the like, and the steering inner brake is operated in accordance with the steering operation of the steering handle. Thus, the vehicle body is steered.

[0003]

In a conventional working vehicle equipped with the crawler-type traveling device, it is conceivable to slowly rotate the vehicle body while maintaining the rotation of the right and left crawlers at a preset rotation ratio. When working on a running surface with a particularly large resistance of the ground, such as a wetland field, the rotation ratio of the right and left becomes inappropriate depending on the condition of the ground, and the rotation of one crawler locks and roughens the ground, Or,
The operator may turn the steering wheel too far.

Therefore, when a work vehicle equipped with a crawler-type traveling device turns the vehicle body by adjusting the left-right rotation ratio of the transmission mechanism, one of the crawlers is locked or the lock is restrained depending on the state of the ground. Therefore, a technical problem to be solved arises in order to enable the turning radius of the vehicle body to be arbitrarily adjusted, and an object of the present invention is to solve this problem.

[0005]

SUMMARY OF THE INVENTION The present invention has been proposed to achieve the above object. A transmission case 23 is provided at the rear of a vehicle body, and a crawler type traveling device C is provided on the left and right sides of the transmission case 23. In the working vehicle to be supported, the right and left crawler-type traveling devices C have transmission mechanisms 72 and 76 for changing the output rotation, a sensor 89 for detecting the output rotation of the transmission mechanism, and an output of the transmission mechanism. Adjustment means 74 and 75 capable of arbitrarily adjusting the rotation are provided, and a control unit 90 for shifting the output rotation of the transmission mechanisms 72 and 76 to a predetermined rotation ratio in accordance with the steering operation amount of the vehicle body is provided. The power transmission control device for a work vehicle provided, and the power transmission control device for a work vehicle provided with setting means 99 for setting the output rotation of the transmission mechanism, and the transmission mechanism controls the rotation of the output shaft 11. Hydraulic clutch mechanism 74 for rolling,
75 and a planetary gear mechanism 76, the control valve increases the pressure oil sent to the hydraulic clutch mechanisms 74 and 75 to change the output rotation of the planetary gear mechanism 76, and sequentially reduces, stops, and reverses the rotation of the crawler. The power transmission control device for a working vehicle configured to switch to the above-described mode, and the transmission mechanism include hydraulic clutch mechanisms 74 and 75 for reversing the rotation of the output shaft 11 and a planetary gear mechanism 76. By controlling the control valve in accordance with the position and limiting the amount of pressurized oil sent to the hydraulic clutch mechanisms 74 and 75, the output rotation of the planetary gear mechanism 76 is changed, and the rotation of the crawler is sequentially reduced. Stop,
An object of the present invention is to provide a power transmission control device for a work vehicle configured to switch to reverse rotation.

[0006]

An embodiment of the present invention will be described below in detail with reference to the drawings. 1 and 2 show a crawler-type tractor 10 as an example of a work vehicle, and a rear axle 1
1, a driven sprocket 14 and a rolling wheel 15 are pivotally connected to a track frame 13 which rotatably supports the driving sprocket 12, and a crawler 16 is wound between the driving sprocket 12 and the driven sprocket 14 and the rolling wheel 15. The front end of the track frame 13 is fixed to the body frame 17 to form a crawler type traveling device C. Reference numeral 23 denotes a transmission case, and the crawler traveling device C is supported on the left and right sides of the transmission case 23 and protrudes rearward from the transmission case 23. The crawler 16 of the traveling device C is It is located behind the rear end of the vehicle body. As will be described later, the rotational power of the engine 46 is input to the transmission case 23, transmitted to the rear axle 11 after being shifted by a transmission in the transmission case 23, and the driving sprocket 12 rotates to drive the crawler 16. You.

[0007] In the vicinity of the driver's seat 18, a position lever 40 for setting the elevation position of the ground work machine 26, a cultivation depth adjustment dial 41 for setting the cultivation depth of the ground work machine 26, and a left-right direction of the ground work machine 26. A horizontal adjustment dial 42 for setting the inclination and the like are provided, and a slope sensor 43 for detecting a horizontal rolling angle of the vehicle body is provided below the driver's seat 18. Further, in front of the driver's seat 18, a rotary operation type steering handle 19 which is a steering operation section is provided.
The steering handle shaft 20 is inserted into a steering handle column 21, and a steering operation device 22 is mounted on a base end thereof. Further, a brake pedal 44 is provided on the right side of the steering handle column 21, and a clutch pedal 45 is provided on the left side of the steering handle column 21. Note that a controller 90 as a control unit is provided below the driver's seat 18.

A ground working machine 26 such as a rotary is connected to a rear portion of the vehicle body via a link mechanism 25. The link mechanism 25 includes a top link 27 and left and right lower links 28, 28. Lift arm 29,2
9 and the lower link 28, 28 with the lift rod 30,
By connecting the lift arm 29 by driving the lift cylinder 32, the lift rod 30,
The lower links 28, 28 move up and down via 30. In this way, the ground working machine 26 moves up and down around the tip ends of the lower links 28, 28 as the center of rotation.

A lift arm angle sensor 33 is provided at the rotation base of the lift arm 29 as a sensor for detecting the elevation position of the ground work machine 26. The lift arm angle sensor 33 controls the rotation angle of the lift arm 29. The height of the ground work machine 26 is detected and calculated. A rear cover 35 is rotatably attached to the rear end of the main cover 34 of the ground work machine 26.
5 to detect the turning angle of the ground work machine 26 and control the plowing depth.

On the other hand, as an actuator for changing the horizontal inclination of the ground work machine 26 with respect to the vehicle body, a rolling cylinder 3
7, the rolling angle of the ground work machine 26 can be changed by extending and contracting the rolling cylinder 37 to change the lift amount of the lower link 28 between left and right.
A stroke sensor 38 is provided adjacent to the rolling cylinder 37. The stroke sensor 38 detects the length of expansion and contraction of the rolling cylinder 37, measures the rolling angle of the ground work machine 26 with respect to the vehicle body, and adjusts the horizontal adjustment dial. The rolling cylinder 37 is driven to expand and contract in accordance with the set value of 42, so that the rolling control of the ground work machine 26 can be performed.

Next, the tractor 10 will be described with reference to FIGS.
The configuration of the power transmission control device will be described. The transmission case 23 is a front transmission case 23a.
, A mid-mission case 23b and a rear transmission case 23c.
Rear axle cases 47, 47 are connected to the left and right sides of the vehicle to support the crawler type traveling device C. A power input shaft 48 projects from the front of the front transmission case 23a, and an engine rotation output shaft 49 and a power input shaft 48 surrounded by the body frame 17 are coaxially connected.

The rotational power of the engine 46 is input from the engine rotational output shaft 49 and the power input shaft 48 into the front transmission case 23a, first transmitted to the lower part of the case by the reduction gear 50, and then transmitted to the rear main clutch 51. And transmitted to a hydraulic pump 52 provided at the front of the front transmission case 23a. The power that is turned on and off by the main clutch 51 is transmitted to the main transmission 53 and the subtransmission 5 in the mid-transmission case 23b.
4, a pinion shaft 5 which is appropriately decelerated and becomes an auxiliary transmission output shaft
5 is transmitted to the rear transmission case 23c.

The main transmission 53 includes a main transmission drive shaft 56.
Between the first speed to the third speed and the main speed
A so-called key shift in which power is transmitted through any one of the gear sets 58 by providing a gear set 58 having a reverse speed and operating a slide key 59 provided in the main speed driven shaft 57 back and forth. It is a type transmission mechanism.

The auxiliary transmission 54 is provided with an auxiliary transmission drive shaft 60 on the extension of the main transmission drive shaft 56, and the auxiliary transmission drive shaft 60 is provided with two-stage gears 61 for “high speed” and “low speed”. 6
2 is provided, while a sub-transmission driven shaft, that is, the pinion shaft 55 is provided on an extension of the main transmission driven shaft 57, and the pinion shaft 55 is engaged with the two-stage gears 61 and 62 by a sliding two-stage gear 63. The transmission is provided by a constant mesh type gear provided with.

Reference numeral 64 denotes a PTO transmission shaft, which transmits power to a rear PTO shaft 66 projecting from a rear portion of the rear transmission case 23c via a PTO transmission 65 provided in the rear transmission case 23c.

A support shaft 68 is provided between the left and right side walls of the rear transmission case 23c, and a bevel gear 69 that meshes with the pinion shaft 55 is spline-fitted at a position slightly deviated from the center of the support shaft 68. A brake disk 70 is provided at a position substantially opposite to the left and right.
Then, the brake pedal 44 and the brake disc 70 are connected by a link mechanism (not shown). Since the power transmission control device shown in the present embodiment does not have a rear differential gear, it is sufficient to dispose the brake disc 70 only at one position on the left and right, and a brake pedal 44 is provided on the right side of the steering handle column 21. Therefore, by arranging the brake disk 70 on the right side, the link mechanism can be simplified.

The brake disc 70 is pressed by the depression operation of the brake pedal 44, and the rotation of the support shaft 68, that is, the rotation of the left and right crawlers 16, 16 is braked. A reduction gear set 71 is provided at both left and right ends of the support shaft 68 to transmit the rotation of the bevel gear 69 to a forward / reverse switching device 72 in the rear axle case 47.

The rear axle case 47 is a substantially cylindrical casting case, and includes a wet multi-plate reverse rotation clutch 74 (inside the vehicle body) and a drive shaft 73 driven through the reduction gear set 71. Forward rotation clutch 75 (outside the vehicle)
And a so-called two-stage planetary gear mechanism 76 having a counter gear is provided outside the forward rotation clutch 75 to constitute a transmission mechanism for shifting the output rotation.
The forward rotation clutch 75 includes an internal spring 77.
, So that it is always crimped. In this state,
A drive-side sun gear 78 integral with the drive-side disk of the forward rotation clutch 75 and a carrier 79 integral with the planetary gears and the driven-side disk meshing therewith rotate integrally with the drive-side sun gear 78 as a center, The rotation of the bevel gear 46 is transmitted from the driving sun gear 78 to the driven sun gear 80 at a one-to-one rotation ratio.

When pressure oil is supplied to the piston portion 81 of the reverse rotation clutch 74, the pressure of the disk of the normal rotation clutch 75 is gradually released in a reciprocal manner, so that the drive side disk and the driven side disk are disengaged from each other. A rotation difference is generated between them, and accordingly, the rotation transmitted to the driven sun gear 80 is reduced. When the pressure oil is continuously fed to the piston portion 81 and the amount of movement of the piston is increased toward the inside of the vehicle body in the figure, the press-fit of the disk of the forward rotation clutch 75 is completely released, and the rotation of the driven side sun gear 80 becomes zero. , The rotation of the crawler 16 stops, and the clutch enters the disengaged state. If the pressurized oil is further sent to the piston portion 81 after the disengagement state, the drive-side disk and the driven-side disk of the reverse rotation clutch 74 are gradually pressed, and the carrier 7
9 is transmitted to the driven-side sun gear 80 via the two-stage planetary gear 76. Therefore, the rotation of the bevel gear 69 is transmitted to the driven-side sun gear 80 by reverse rotation, and the rotation of the crawler 16 is driven in reverse rotation. The reverse rotation clutch 7
4. An adjusting means capable of arbitrarily adjusting the output rotation is constituted by the forward rotation clutch 75 and the like.

The rotation ratio at the time of the reverse rotation is set to approximately 30% of the rotation at the time of the forward rotation, but the means for operating the reverse rotation clutch 74 is interlocked with the turning operation of the tractor 10. The configuration may be such that only the crawler 16 inside the turning is reversed, or the left and right reversing clutches 74, 74 may be simultaneously pressed to move the vehicle backward. Further, as described later, the amount of depression of the clutch pedal 45 is detected, and the forward rotation clutch 7 is detected.
5. If the disengagement state is maintained by using a transmission mechanism including the reverse rotation clutch 74 and the two-stage planetary gear mechanism 76, the main clutch 51 can be eliminated.

The driven-side sun gear 80 is provided with a cover 8 for shielding the outside opening of the rear axle case 47.
2 and the lid 8
2 is made of the same casting as the rear axle case 47, and has a bolt hole 8 for connection with the rear axle case 47.
An outer lid portion 82a having 3, 83...
Inner cover 82 that is attached to the inner surface of the
b and a ring gear 84 interposed between the outer lid portion 82a and the inner lid portion 82b. A pack-shaped space 85 is formed between the outer lid 82a and the inner lid 82b,
A planetary gear mechanism 87 for reducing the rotation of the input shaft 86 and transmitting the rotation to the output shaft, that is, the rear axle 11, is provided in the space 85.

Reference numeral 88 denotes a rotation detecting gear.
A non-contact type rotation detection sensor 89 is arranged close to the rotation detection gear 88 so that output rotations to the right and left crawlers 16 and 16 can be detected. Also,
The planetary gear mechanism 87 in the lid 82 can arbitrarily change the reduction ratio according to the specification change of the tractor 10, such as when changing between the wheel specification and the crawler specification or when changing the wheel diameter of the wheel specification. A mechanism that can be changed may be used.

FIG. 6 is a block diagram of a control system. Inside the controller 90, which is a control unit, a CPU for performing arithmetic processing of various information, a RAM for storing various sensor values and set values, a control program, and the like. The input section of the controller 90 has setting signals such as a position lever 40, a tillage depth adjustment dial 41, a horizontal adjustment dial 42, a lift arm angle sensor 33, a slope sensor 43, a left Crawler rotation sensor 89, left crawler rotation sensor 89, steering angle sensor 91,
Throttle position sensor 92, left brake pedal sensor 9
3. Detection signals from the right brake pedal sensor 93, the clutch pedal sensor 94, the main shift lever sensor 96, the engine speed sensor 97, the clutch adjustment dial 99, and the like are input.

Also, based on these input signals, an up solenoid or a down solenoid of the control valve for the lift cylinder 32 is output from the output of the controller 90.
Control valve for the rolling cylinder 37, an extension solenoid or a contraction solenoid, a brake disc 7
Operation signals are output to the brake solenoid of the control valve for zero, the clutch solenoid of the control valve for the left forward / reverse switching device 72, the clutch solenoid of the control valve for the right forward / reverse switching device 72, the governor adjusting actuator 98, and the like.

FIG. 7 shows the magnitude of the clutch current (clutch cylinder pressure) output from the controller 90 and the crawler 1
6 shows the relationship with the rotation state, for example, when the clutch current is 0 A in the forward running state, the clutch cylinder pressure is 0 kg / c.
m ² , the forward rotation clutch 75 is connected at full pressure, and the crawler 16 is driven to rotate in the forward direction. Controller 90
When the clutch current is gradually increased to increase the clutch cylinder pressure output to the clutch solenoid of the forward / reverse switching device 72, the forward rotation clutch 75 slips when the clutch current is around 0.2 A, and the crawler 16 moves forward. The rotation in the direction decreases. When the clutch current increases to around 0.4 A, the clutch cylinder pressure becomes about 10 kg / cm ^2, and both the forward rotation clutch 75 and the reverse rotation clutch 74 maintain the disengaged state. For this reason, the rotational power transmitted from the pinion shaft 55 to the support shaft 68 is not transmitted to the rear axle 11, and the crawler 16 is not driven.

In this state, when the clutch current is further increased to about 0.6 A, the reverse rotation clutch 74 is engaged while slipping, and the crawler 16 starts rotating in the reverse direction in the half-clutch state. When the clutch current is increased to around 0.8 A, the clutch cylinder pressure becomes 20 kg / cm ² and the reverse rotation clutch 74 is connected at full pressure. Therefore, the support shaft 6 is
8 is transmitted to the rear axle 11 in reverse, and the crawler 16 is driven to rotate in the reverse direction.

As described above, by changing the clutch current output from the controller 90, the clutch cylinder pressure of the forward / reverse switching device 72 is increased or decreased, and the connection state of the forward clutch 75 and the reverse clutch 74 is continuously changed. Change. That is, the clutch of the forward / reverse switching device 72 does not have a general neutral position (neutral), and has a continuous driving torque between forward rotation and reverse rotation while continuously changing the rotation direction and rotation speed of the crawler 16. It can be adjusted appropriately and arbitrarily.

The steering operation (rotation operation) of the steering handle 19 is detected by the steering angle sensor 91, and the forward / reverse switching device 72 of one of the forward / reverse switching devices 72 is operated in accordance with the steering operation amount (change of the steering angle). By controlling the clutch and decelerating the rotation of the crawler 16 inside the turning, the vehicle body can be turned by giving a rotation difference to the right and left crawlers 16, 16. On relatively hard ground, the crawler 16 inside the turn may be stopped or reversed, causing the vehicle to turn sharply.However, if the rotation of the crawler 16 is locked during the turn, the ground is likely to be rough, so usually the forward and reverse rotation inside the turn The vehicle body is slowly turned by sliding the clutch of the switching device 72 to reduce the rotation of the crawler 16 inside the turn.

For example, in the forward running state, when the clutch current is 0 A, that is, when the clutch cylinder pressure is 0 kg / cm ² , the right and left forward rotation clutches 75 and 75 are connected at full pressure, and both the left and right crawlers 16 and 16 are connected. It is driven to rotate forward.
Then, when the steering operation of the steering handle 19 is performed, the clutch current to the clutch solenoid of the forward / reverse switching device 72 on one side (the inside of the rotation) is gradually increased, and the clutch cylinder pressure is increased, and the clutch current is increased. At about 0.2A, slippage occurs in the forward rotation clutch 75,
Since the rotation of one of the crawlers 16 in the forward direction decreases, a rotation difference occurs between the left and right crawlers 16, 16 and the vehicle body turns. By maintaining this clutch slip state, the vehicle body turns slowly without breaking the ground (brake turn)
Can be done.

When the clutch current for the clutch solenoid of one of the forward / reverse switching devices 72 (inside the turning) is increased to about 0.4 A, the clutch cylinder pressure becomes about 10 kg / cm ² , and the one forward clutch 75 Both the reverse rotation clutch 74 and the reverse rotation clutch 74 maintain the disengaged state. For this reason, the rotational power transmitted from the pinion shaft 55 to the support shaft 68 is not transmitted to the one rear axle 11, the rotation of the crawler 16 inside the turn is locked, the turning radius is reduced, and the vehicle body is pivotally turned ( Lock turn).

When the clutch current to the clutch solenoid of one of the forward / reverse switching devices 72 (inside the turning direction) is increased to about 0.8 A, the clutch cylinder pressure becomes 20 kg / cm ^2, and The clutch 74 is connected at full pressure. For this reason, the rotational power transmitted from the pinion shaft 55 to the support shaft 68 is reversed and transmitted to one of the rear axles 11, and the crawler 16 inside the turning is driven to rotate backward. Therefore, the left and right crawlers 16 and 16 rotate in opposite directions to each other to minimize the turning radius, and the vehicle body can be turned in a spin turn.

Here, the clutch adjusting dial 99 is a setting means for setting the output rotation of the transmission mechanism. Depending on the setting of the clutch adjusting dial 99, the step-up characteristic of the clutch of the forward / reverse switching device 72 can be changed in several steps or steplessly. Can be changed with. As shown in FIG. 8A, when the set position of the clutch adjustment dial 99 is at the position,
As shown by the solid line in FIG. 3B, as the steering operation amount of the vehicle body increases, that is, as the steering angle increases, the clutch cylinder pressure inside the turn increases relatively slowly, and the clutch cylinder pressure increases. Also keep the maximum value low. Therefore, the forward rotation clutch 75 slips in response to the turning operation of the steering handle 19, and the rotation speed of the crawler 16 inside the turning decreases. By holding the clutch slipping state, the vehicle body is gentle swirling S _1.

When the set position of the clutch adjusting dial 99 is set to the position indicated by the dashed line in FIG. 9B, the clutch cylinder pressure on the inside of the turn rises slightly earlier. Accordingly, when the rotation of the crawler 16 on the inner side of the turning decreases rapidly and the clutch cylinder pressure becomes maximum (about 10 kg / cm ² ), both the forward rotation clutch 75 and the reverse rotation clutch 74 are disengaged. a state, the rotation of the turning inner crawler 16 is locked down, the body of the turning radius becomes small pivot turn (lock turns) S ₂ than the set position described above.

When the clutch adjustment dial 99 is set to the set position, the clutch cylinder pressure on the inside of the turn rises earlier as shown by the two-dot chain line in FIG. Both the forward rotation clutch 75 and the reverse rotation clutch 74 are disconnected, and the reverse rotation clutch 74 is connected while slipping. Therefore, after the rotation of the crawler 16 inside the turn is decelerated and stopped, the crawler 16 starts to rotate in the reverse direction in the half-clutch state, and the turning radius of the vehicle body becomes smaller than the above-mentioned set position.

When the set position of the clutch adjustment dial 99 is set to the position indicated by the dotted line in FIG. 9B, the clutch cylinder pressure inside the turning portion sharply increases, and the maximum value of the clutch cylinder pressure becomes It is about 20 kg / cm ² . Therefore, via the state of setting the position as described above, further, the reverse rotation clutch 74 is connected at a total pressure, left and right crawlers 16, 16 is ultra stationary turn (spin turn) S ₃ that rotates in the opposite direction to each other Therefore, the turning radius of the vehicle body is minimized.

As described above, the clutch adjusting dial 9
9, the right and left crawlers are changed according to the conditions of the field, the type and temperature of the oil, the aging of the clutch, and the demands of the operator by changing the pressure increasing characteristics of the clutch of the forward / reverse switching device 72. Traveling device C, C
, The turning radius of the vehicle body can be arbitrarily changed.

The present invention can be variously modified without departing from the spirit of the present invention, and it goes without saying that the present invention extends to the modified ones.

[0038]

According to the present invention, as described in detail in the above embodiment, the invention according to claim 1 is provided with adjusting means capable of arbitrarily adjusting the output rotation of the transmission mechanism provided in the left and right crawler type traveling devices. Since the output rotation of the transmission mechanism is controlled to a preset rotation ratio in accordance with the steering operation amount of the vehicle body, the turning radius of the vehicle body can be adjusted arbitrarily, and the turning performance can be improved. .

According to a second aspect of the present invention, there is provided a setting means for setting an output rotation of the transmission mechanism.
Ground state, the vehicle body and the device state, as desired, such as the operator, by restraining the lock or locks the rotation of one of the crawler, it is possible to set the optimum speed ratio.

The third and fourth aspects of the present invention are configured to change the output rotation of the planetary gear mechanism by increasing the pressure oil sent to the hydraulic clutch mechanism by the control valve. It is possible to continuously switch between deceleration, stop, and reverse rotation, thereby improving turning performance and smoothing.

[Brief description of the drawings]

 The figure shows an embodiment of the present invention.

FIG. 1 is a side view of a crawler type tractor.

FIG. 2 is a rear view of the crawler type tractor.

FIG. 3 is a diagram showing a configuration of a power transmission control device in a transmission case.

FIG. 4 is a diagram showing a configuration of a power transmission control device in a rear axle case.

FIG. 5 is a diagram showing a power transmission path.

FIG. 6 is a block diagram of a control system.

FIG. 7 is a graph showing a relationship between a clutch cylinder pressure and a rotation state of a crawler.

8A is a front view of a clutch adjustment dial, and FIG. 8B is a graph showing a relationship between a steering angle and a clutch cylinder pressure which change according to a set position of the clutch adjustment dial.

[Explanation of symbols]

 16 Crawler 19 Steering handle 23 Transmission case 72 Forward / reverse switching device 74 Reverse rotation clutch 75 Forward rotation clutch 76 Two-stage planetary gear mechanism 89 Rotation detection sensor 90 Controller C Crawler traveling device

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor: Masayuki Takahashi No. 1, Yatsukura, Tobe-cho, Iyo-gun, Ehime Pref. JJ37

Claims (4)

[Claims] 1. In a work vehicle having a transmission case 23 provided at a rear portion of a vehicle body and supporting a crawler type traveling device C on the left and right sides of the transmission case 23, output power is applied to each of the left and right crawler type traveling devices C. Transmission mechanisms 72 and 76 for changing the rotation speed, a sensor 89 for detecting the output rotation of the transmission mechanism, and adjusting means 74 and 75 for arbitrarily adjusting the output rotation of the transmission mechanism are provided. A power transmission control device for a work vehicle, comprising: a control unit 90 for shifting the output rotations of the transmission mechanisms 72 and 76 so as to have a preset rotation ratio in accordance with the speed. 2. The power transmission control device for a work vehicle according to claim 1, further comprising setting means for setting an output rotation of said transmission mechanism. 3. The transmission mechanism includes hydraulic clutch mechanisms 74 and 75 for reversing the rotation of the output shaft 11 and a planetary gear mechanism 76, and controls hydraulic oil sent to the hydraulic clutch mechanisms 74 and 75 by a control valve. 2. The system according to claim 1, wherein the output rotation of the planetary gear mechanism is changed to increase, and the rotation of the crawler is sequentially switched to deceleration, stop, and reverse rotation.
Or the power transmission control device for a work vehicle according to 2. 4. The transmission mechanism comprises hydraulic clutch mechanisms 74 and 75 for reversing the rotation of the output shaft 11 and a planetary gear mechanism 76. The transmission mechanism controls a control valve in accordance with a setting position of a setting means 99, and Type clutch mechanism 74,
3. The apparatus according to claim 1, wherein an output rotation of the planetary gear mechanism is changed by limiting an increase amount of the pressure oil sent to the rotation of the planetary gear, and the rotation of the crawler is sequentially switched to deceleration, stop, and reverse rotation. Power transmission control device for work vehicle.