JP2003040133A - Steering control device for crawler working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering control device for a working vehicle for changing the output revolving speeds of crawler travelling gears corresponding to the rotation control input of a steering handwheel, preventing the turning performance of a vehicle body from being worsened by the deviation of right and left output revolving speeds from target values. SOLUTION: A target output speed ratio between right and left crawler travelling gears is preset corresponding to a steering turning angle and the pressure of a multiple disc clutch is controlled to gain the target speed ratio. When actual output revolving speeds deviate from the target values, the target values are corrected with reference to correction values in a correction table.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering control device for a crawler type work vehicle, and more particularly to a steering control device for a crawler type work vehicle in which an output speed can be corrected with respect to a rotating operation of a steering wheel. It relates to the device.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
This type of crawler type work vehicle is provided with crawler type traveling devices on the left and right of the vehicle body, and transmission mechanisms for shifting the output speed to the crawler type traveling device by actuation of actuators are arranged on the left and right respectively. Then, a sensor for detecting the output rotational speed is installed on each of the left and right sides of the transmission mechanism, and a turning angle sensor for detecting the steering operation amount of the steering wheel is provided, and the actuator is connected to the actuator according to the detection value of the turning angle sensor. By outputting an operation signal, the steering state of the vehicle body is adjustable.

However, the operation of the actuator may deviate with respect to the steering operation amount of the steering wheel, and the left and right output rotational speeds may deviate from the target values. In that case, a feeling of strangeness occurs in the operation of the steering wheel, and the turning performance of the vehicle body deteriorates.

Therefore, in a steering control device for a work vehicle, which changes the output rotation speed of a crawler type traveling device in accordance with the rotational operation amount of a steering wheel, the left and right output rotation speeds deviate from a target value and the vehicle body turns. There are technical issues that need to be resolved in order to prevent performance deterioration.
The present invention aims to solve this problem.

[0005]

In view of the above problems, the present invention has a steering control device for a work vehicle configured as follows.
That is, the invention according to claim 1 is provided with the crawler type traveling device C on the left and right of the vehicle body, and the output rotation speed to the crawler type traveling device C is changed by changing the crimping force in the multi-plate clutch by the operation of the actuator 147. A transmission mechanism 73 for shifting the speed is arranged on each of the left and right sides, a sensor 107 for detecting the output rotation speed is installed on each of the left and right sides of the transmission mechanism 73, and a turning angle sensor 128 for detecting a steering operation amount of the steering wheel 19 is provided. A left and right crawler type traveling device in a crawler type work vehicle which is provided to output an operation signal to the actuator 147 according to a detection value of the cutting angle sensor 128 so that a steering state of a vehicle body can be adjusted. The rotation speed ratio is detected from the output rotation speed to C, and the detected rotation speed ratio is outside the target rotation speed ratio according to the detection value of the cut angle sensor 128. In this case, a steering control device for a crawler type work vehicle, comprising: a control unit 100 that corrects the pressure of the multi-plate clutch based on a preset correction value to control to obtain a target rotation ratio. did.

Further, in the invention according to claim 2, the correction value is a table correction value defined for the target rotation speed ratio according to a difference between the target rotation speed ratio and the detected rotation speed ratio. The steering control device for the crawler type work vehicle described in 1. Further, in the invention according to claim 3, in the pressure correction to the multi-disc clutch, correction limit pressures are set on the pressure increasing side and the pressure reducing side of the target pressure, respectively, and the correction limit pressures on the pressure increasing side or the pressure reducing side are set. 3. The steering control device for a crawler type work vehicle according to claim 1, wherein the correction limit pressure on the side where the rotation difference between the left and right crawlers is large is set to be smaller than the correction limit pressure on the side where the rotation difference is small. And

Further, in the invention according to claim 4, the table correction value is determined for each vehicle speed, and as the detection value of the turning angle sensor 128 increases, the vehicle body slowly turns, a turning turn, and a super turning point in a low speed range. The steering control device for a crawler-type work vehicle according to claim 1, further comprising a control unit 100 that corrects even turning.

Further, the invention according to claim 5 is provided with a control unit 100 for correcting the vehicle body to make a gentle turn or a solid turn in the medium speed range in accordance with an increase in the detection value of the turning angle sensor 128. The steering control device for the crawler type work vehicle described in 2, 3, or 4. Further, the invention according to claim 6 is provided with a controller 100 for correcting the vehicle body up to a gentle turn in a high speed range with an increase in the detection value of the turning angle sensor 128. The steering control device for the crawler type work vehicle described above is used.

[0009]

When the output speed to the crawler type traveling device deviates from the target value, the pressure of the multi-disc clutch is set based on a preset correction value. Is controlled to obtain the target rotation ratio, so that the steering performance of the vehicle body is improved without causing a feeling of strangeness in the operation of the steering wheel.

According to a second aspect of the present invention, the correction value is a table correction value defined for the target rotation speed ratio according to the difference between the target rotation speed ratio and the detected rotation speed ratio. In addition to the effect of the invention described in 1, the configuration of the program is simplified as compared with the case where the controller calculates the correction value as needed.
Moreover, the processing time can be shortened.

According to a third aspect of the present invention, correction limit pressures are set on the pressure increasing side and the pressure reducing side of the target pressure, respectively.
Since the correction limit pressure on the side where the rotation difference between the left and right crawlers is large is set smaller than the correction limit pressure on the side where the rotation difference is small, in addition to the effect of the invention according to claim 1 or 2, In this case, it becomes difficult for the vehicle to make a sharp turn, and steering safety can be secured.

According to the invention of claim 4, the table correction value is determined for each vehicle speed. Therefore, in addition to the effect of the invention of claim 1, 2 or 3, the optimum correction is made in accordance with the running state of the vehicle body. You can get the value. The invention described in claim 5 and the invention described in claim 6 have the same effects as the invention described in claim 4, respectively.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to the drawings. 2 and 3 show a crawler type tractor 10 as an example of a work vehicle, and the rear axle 1
1, a drive sprocket 12 is attached, a driven sprocket 14 and a rolling wheel 15 which pivotally support the driving sprocket 12 are pivotally mounted, and a crawler 16 is mounted between the driving sprocket 12, the driven sprocket 14 and the rolling wheel 15. The front end of the track frame 13 is fixed to the vehicle body frame 17 to form a crawler type traveling device C. Reference numeral 23 is a mission case, and the crawler type traveling device C is supported on the left and right sides of the mission case 23 and projects rearward from the mission case 23. The crawler 16 of the crawler type 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 mission case 23, transmitted to the rear axle 11 after being changed by the transmission in the transmission case 23, the drive sprocket 12 rotates, and the crawler 16 is driven. It Since the engine 46 is located in front of the front end of the crawler 16 and the ground work implement 26 is located behind the rear end of the crawler 16, the front-rear balance of the vehicle body is good.

In the vicinity of the driver's seat 18, a position lever 40 for setting the up / down position of the ground work implement 26, a plowing depth adjusting dial 41 for setting the working depth of the ground work implement 26, and a left / right direction of the ground work implement 26. A horizontal adjustment dial 42 for setting the inclination is provided, and a slope sensor 43 for detecting the horizontal rolling angle of the vehicle body is installed 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 unit 22 is attached to the base end thereof. The steering unit 22 includes a steering handle 19 as described later.
A steering angle sensor 128 is provided to detect the steering operation amount of the. 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. A controller 100, which is a control unit, is provided below the driver's seat 18.

A ground work machine 26 such as a rotary is connected to the rear portion of the vehicle body via a link mechanism 25. The link mechanism 25 is composed of a top link 27 and left and right lower links 28, 28. Lift arms 29,2
9 and the lower link 28, 28 the lift rod 30,
30 and the lift cylinder 29 is driven to rotate the lift arm 29.
The lower links 28, 28 move up and down via 30. Thus, the ground work machine 26 moves up and down around the tip of the lower links 28, 28 as the center of rotation. If the position of the tip of the lower link 28, that is, the position of the pivot of the ground work implement 26 is A, the position B of the rear end of the crawler 16 is behind it.

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 determines the rotation angle of the lift arm 29. The height of the ground work machine 26 is detected and calculated. Further, a rear cover 35 is rotatably attached to the rear end portion of the main cover 34 of the ground work implement 26, and the rear cover sensor 36 is used to rotate the rear cover 3
5 is formed so that the working depth of the ground work implement 26 can be controlled by detecting the rotation angle of the ground work implement 5.

On the other hand, as the actuator for changing the inclination of the ground work machine 26 with respect to the vehicle body in the left-right direction, the rolling cylinder 3 is provided in the middle of either the left or right lift rod 30.
7 is provided, and the rolling cylinder 37 is expanded and contracted to change the lift amount of the lower link 28 to the left and right, so that the rolling angle of the ground work machine 26 can be changed.
A stroke sensor 38 is provided adjacent to the rolling cylinder 37. The stroke sensor 38 detects the extension / contraction length of the rolling cylinder 37 to measure the rolling angle of the ground work implement 26 with respect to the vehicle body, and the horizontal adjustment dial. The rolling cylinder 37 is extended / contracted according to the set value of 42, and the rolling control of the ground work machine 26 can be performed.

The structure of the power transmission system will be described with reference to FIGS. The mission case 23 is composed of a front mission case 23a, a mid mission case 23b, and a rear mission case 23c. The power input shaft 4 is provided on the front of the front mission case 23a.
The engine rotation output shaft 49 and the power input shaft 48 surrounded by the vehicle body frame 17 are coaxially connected to each other.

Rotational power of the engine 46 is input from the engine rotation 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. At the same time, it is transmitted to the hydraulic pump 52 provided in the front part of the front mission case 23a. The power that is turned on and off by the main clutch 51 is the main transmission 53 and the auxiliary transmission 5 in the mid mission case 23b.
4, the pinion shaft 5 that is appropriately decelerated and serves as the auxiliary transmission output shaft
5 is transmitted to the rear transmission case 23c via A support shaft 68 is provided between the left and right side walls of the rear mission case 23c, and a bevel gear 69 meshing with the pinion shaft 55 is spline-fitted at a position slightly offset from the center of the support shaft 68.

The main transmission device 53 includes a main transmission drive shaft 56.
1 to 3 forward speed and 1
A so-called key shift in which power is transmitted through any one gear set 58 by providing a gear set 58 having a reverse speed of one stage and operating a slide key 59 provided in the main shift driven shaft 57 back and forth. It is a variable speed mechanism.

Further, the auxiliary transmission 54 has an auxiliary transmission drive shaft 60 pivotally mounted on an extension of the main transmission drive shaft 56, and the auxiliary transmission drive shaft 60 has a two-stage gear for "high speed" and "low speed". 61,
While 62 is fixedly provided, an auxiliary transmission driven shaft, that is, the pinion shaft 55 is provided on an extension of the main transmission driven shaft 57. Then, a slide type two-stage gear 63 is provided on the pinion shaft 55, and the slide type two-stage gear 63 is slid so that
The transmission is a so-called constant mesh type gear that meshes with one of the stepped gears 61 and 62. still,
Reference numeral 64 denotes a PTO transmission shaft, which passes through a PTO transmission device 65 provided in the rear mission case 23c, and a rear PTO shaft 66 projectingly provided at the rear portion of the rear mission case 23c.
Transmits power to.

Reference numeral 47 is a rear axle case 47 provided on the left and right sides of the rear mission case 23c, and the rear axle case 47 is a substantially cylindrical casting case.
The rear axle case 47 supports the crawler type traveling device C. As described above, a support shaft 68 is pivotally mounted between the left and right side walls of the rear mission case 23c, and a bevel gear 69 that meshes with the pinion shaft 55 is spline-fitted at a position slightly left of the center of the support shaft 68. Therefore, a brake disc 70 is provided at a position substantially opposite to the left and right of the bevel gear 69.

The brake pedal 44 and the brake disc 70 are connected by a link mechanism (not shown), and the brake disc 70 is crimped by depressing the brake pedal 44 to support the support shaft 68.
Of the left crawler 16, 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, and the rotation of the bevel gear 69 is controlled by the reduction gear set 71 through the rear axle case 4.
7 is transmitted to the input shaft 72.

Inside the rear axle case 47,
A forward / reverse rotation switching device 73 is arranged as a transmission mechanism for changing the output rotational speed to the crawler type traveling device C and the rotational direction, and the forward / reverse rotation switching device 73 includes the input shaft 72.
An output shaft 74 pivotally mounted on one end of the input shaft 72 coaxially with the input shaft 72; a two-stage planetary gear mechanism 75 interposed between the input shaft 72 and the output shaft 73; Wet multi-plate type forward rotation clutch 77 (outside the vehicle body) and reverse rotation clutch 78 provided on the carrier 76 of the step planetary gear mechanism 75.
(Inside the vehicle). The carrier 76 has a first carrier 76a forming a two-step planetary gear mechanism 75 between two facing surfaces, and a forward rotation clutch 77.
And a second carrier 76b provided with a reverse rotation clutch 78 are integrally formed by bolting.

In the structure of the two-step planetary gear mechanism 75, the input side sun gear 79 is fixed to one end of the input shaft 72, and the output side sun gear 80 is connected to one end of the output shaft 74.
Is fixed. In addition, the input shaft 72 and the output shaft 74
The first carrier 76a is attached so as to be freely rotatable around the axis of and the input shaft 7 is attached to the first carrier 76a.
A plurality of first carrier pins 81, 81 ... Are provided on the same circumference centered on 2. In this embodiment, three first carrier pins 81, 81, 81 are provided at equal intervals on the same circumference.

The input side planetary gears 82 and the output side planetary gears 8 are attached to the respective first carrier pins 81.
3 is coaxially and integrally pivoted. Further, the carrier 76
There are as many second carrier pins 8 as there are first carrier pins 81.
4 are provided at equal intervals on the same circumference, and counter gears 85 are pivotally attached to the respective second carrier pins 84.
5 is the output side planetary gear 83 and the output side sun gear 8
It is meshed with both 0. That is, the first carrier 76
The first and second carrier pins 8 are provided between the two facing surfaces of a.
1, 84 are provided to form a two-stage, six-axis planetary gear mechanism.

A carrier pin fixing plate 86 is bolted to the outer surface of the first carrier 76a, and the carrier pin fixing plate 86 is attached to the first carrier 76a.
It is made larger than the outer shape of a and protrudes outward from the outer edge portion, and the tip of the carrier pin fixing plate 86 is bent to provide a cutout portion 86a, which is read by a rotation sensor (not shown). . Therefore, the fixed and rotating states of the first carrier 76a can be easily detected without using a dummy gear or the like. Further, since the tip of the carrier pin fixing plate 86 is bent, the surrounding oil is agitated and the cooling performance can be improved.

On the other hand, the forward rotation clutch 77 and the reverse rotation clutch 78 are provided on the opposite sides with the partition wall 76c of the second carrier 76b sandwiched therebetween, and the drive disk 77a of the forward rotation clutch 77 is the input side sun gear 79, that is, the input. The driven disk 7 of the forward rotation clutch 77 that is integrally engaged with the shaft 72
7b is integrally engaged with the second carrier 76b. Further, the driving disk 77a and the driven disk 77b are alternately overlapped with each other to provide a pressing plate 90 on the partition wall 76c side, and a spring 91 is interposed between the pressing plate 90 and the partition wall 72c. Thus, the pressing plate 90 is urged toward the outside of the vehicle body to press the drive disk 77a and the driven disk 77b into contact with each other.

On the other hand, the drive disk 78a of the reverse rotation clutch 78 is integrally engaged with the rear axle case 47, and the driven disk 78b of the reverse rotation clutch 78 is the second.
Is integrally engaged with the carrier 76b. Further, the driving discs 78a and the driven discs 78b are alternately overlapped with each other to provide a pressing plate 92 on the partition wall 72c side, and a hydraulic piston 93 is interposed between the pressing plate 92 and the partition wall 72c. The pressing plate 90 of the forward rotation clutch 77 and the pressing plate 92 of the reverse rotation clutch 78 are connected by a connecting rod 94 so that both the pressing plates 90 and 92 move integrally. Therefore, when the pressure oil is supplied to the oil chamber 95, the hydraulic piston 93 pushes the pressing plate 92 toward the inside of the vehicle body, and presses the drive disk 78a and the driven disk 78b.

The other end of the output shaft 74 is integrally assembled with a lid 96 that shields the outer opening of the rear axle case 47. The lid 96 is similar to the rear axle case 47. It is made of casting and has bolt holes 97, 9 for connection with the rear axle case 47.
An outer lid portion 96a having 7 ..., an inner lid portion 96b attached to the inner surface of the outer lid portion 96a with a bolt to cover the inner surface,
It is composed of a ring gear 98 and the like interposed between the outer lid portion 96a and the inner lid portion 96b. Further, the outer lid portion 96
A pack-shaped space 99 is formed between a and the inner lid 96b, and one end of the rear axle 11 is pivotally mounted in the space 99 coaxially with the output shaft 74 and the output shaft 7 is provided.
A planetary gear mechanism 101 for decelerating the rotation of No. 4 and transmitting it to the rear axle 11 is internally provided.

The planetary gear mechanism 101 includes the output shaft 7
4, a sun gear 102 fixed to the other end of the rear axle 4, a carrier 103 fixed to one end of the rear axle 11, a carrier pin 104 provided on the carrier 103, and the sun gear that is pivotally attached to the carrier pin 104. Planetary gear 105 that meshes with both 102 and the ring gear 99.
It consists of and. In addition, this planetary gear mechanism 101
May be a mechanism capable of arbitrarily changing the reduction ratio according to the specification change of the tractor 10, such as when the wheel specifications and the crawler specifications are mutually changed or when the wheel diameter of the wheel specifications is changed. . Reference numeral 106 denotes a rotation speed detection gear. A non-contact type rotation sensor 107 is arranged in proximity to the rotation speed detection gear 106, and the left and right crawlers 1 are provided.
It is configured to be able to detect the number of rotations output to 6 and 16.

Next, the operation of the forward / reverse rotation switching device 73 will be described. Normally, the spring 91 causes each disk 77a of the forward rotation clutch 77 to intervene via the pressing plate 90.
77b is crimped, and in this state, the input side sun gear 79 that engages with the drive side disk 77a of the forward rotation clutch 77 and the carrier 76 that engages with the driven disk 77b.
Rotate integrally with each other, so that the rotation of the input shaft 72 is transmitted from the input-side sun gear 79 to the output-side sun gear 80 at a rotation ratio of 1: 1 so that the input shaft 72 and the output shaft 74 rotate in the same direction at the same rotation speed. Rotate.

On the other hand, the oil chamber 95 of the reverse rotation clutch 78.
When pressure oil is fed to the hydraulic piston 93, the hydraulic piston 93
To press each disk 78a of the reverse clutch 78,
78b is crimped. In this state, the reverse rotation clutch 78
Rear axle case 47 that engages with the drive-side disc 78a and a carrier 76 that engages with the driven disc 78b.
The carrier 76 does not rotate because the and are integrated. Therefore, the rotation of the input shaft 72 is decelerated and transmitted from the input sun gear 79 to the input planetary gear 82.
The planetary gear 83 on the output side is transmitted to the sun gear 80 on the output side through deceleration and reverse rotation via the counter gear 85, the input shaft 72 and the output shaft 74 rotate in opposite directions, and the rotation speed thereof is that of the two-step planetary gear mechanism 75. The speed is reduced to a predetermined speed according to each gear ratio.

When the forward rotation clutch 77 is in the engaged state and the input shaft 72 and the output shaft 74 are rotating in the same direction at the same rotation speed, the hydraulic piston 93 causes the reverse rotation clutch 78 to rotate. When the pressing plate 92 is pressed, the pressing plate 92 and the pressing plate 9 of the forward rotation clutch 77 are pressed.
Since 0 and 0 are connected by the connecting rod 94, both pressing plates 90 and 92 move integrally toward the inside of the vehicle body. Therefore, as the discs 78a and 78b of the reverse rotation clutch 78 are pressure-bonded, the pressures of the discs 77a and 77b of the forward rotation clutch 77 are gradually released against the bias of the spring 91. That is, as the hydraulic pressure supplied to the oil chamber 95 increases, the forward rotation clutch 77 slips and the reverse rotation clutch 78 is connected in a half-clutch state, and the rotation speed of the output shaft 74 decreases.

Thus, the rotation speed of the rear axle 11 on one side is reduced, and the drive speed of the crawler 16 is reduced. When the pressure oil is continuously sent to the oil chamber 95 and the movement amount of the hydraulic piston 93 is increased to the inside of the vehicle body in the drawing, the drive disk 77a and the driven disk 77b of the forward rotation clutch 77 are driven.
The pressure contact is completely released, the rotation of the output side sun gear 80 becomes zero, the rotation of the crawler 16 on one side is stopped, and the forward / reverse rotation switching device 73 is switched from the normal rotation state to the cut state. If the pressure oil is further sent to the oil chamber 95 through this cut state, the drive side disk 7 of the reverse rotation clutch 78 is obtained.
8a and the driven side disk 78b are gradually pressed against each other, the output side sun gear 80 rotates in the reverse direction, the crawler 16 on one side is driven in the reverse direction, and the forward / reverse rotation switching device 73 enters the reverse rotation state.

FIG. 8 is a hydraulic circuit diagram. The oil in the transmission case 23 is pumped up by the hydraulic pump 140 and branched into the oil passage L ₁ and the oil passage L ₂ , and the oil in the oil passage L ₁ is divided by the flow dividing valve 141. Is divided into a control valve 142 for the lift cylinder 32 and a control valve 143 for the rolling cylinder 37. A connector 144 is provided between the top side oil passage L ₃ of the rolling cylinder 37 and the control valve 143, and the bottom side oil passage L _{4 of} the rolling cylinder 37 and the control valve 143 are provided.
And a connector 145 is provided between
4, 145 is formed so that the oil passage can be connected or disconnected.

On the other hand, the oil in the oil passage L ₂ is sent to the proportional control valves 147 and 147 for controlling the left and right reverse clutches 78 and 78 via the pressure reducing valve 146. A connector 148 is provided between the oil passage L ₅ of the left reverse rotation clutch and the left proportional control valve 147, and a connector 149 is provided between the oil passage L ₆ of the right reverse rotation clutch and the right proportional control valve 147. Each connector 148,
149 is formed so that the oil passage can be connected or disconnected.

FIG. 9 is a block diagram of a control system. Inside the controller 100, which is a control unit, a CPU for calculating various information and an R for storing various sensor values and set values.
The controller 100 has an AM and a ROM for storing a control program and the like, and an input portion of the controller 100 includes setting signals for the position lever 40, the working depth adjusting dial 41, the horizontal adjusting dial 42, the spin turn switch 114, and the like. Detection signals from the lift arm angle sensor 33, the slope sensor 43, the left and right crawler rotation sensors 107, 107, the steering angle sensor 128, the engine speed sensor 112, the vehicle speed sensor 113, etc. are input.

Further, based on these input signals, from the output part of the controller 100, the solenoid for raising or lowering the control valve 142 for the lift cylinder 32, the solenoid for expanding or contracting the control valve 143 for the rolling cylinder 37, and the solenoid for the brake disc 70 are provided. A control signal is output to the brake solenoid of the control valve, the clutch solenoid of the proportional control valve 147 for the left and right forward / reverse switching devices 73, the governor adjusting actuator, and the like.

The controller 100 is operated by operating the position lever 40 or setting the plowing depth adjusting dial 41.
When a control signal is output from the lift solenoid 32 to the lift solenoid or the lower solenoid of the control valve 142 for the lift cylinder 32, the lift cylinder 32 expands and contracts and the ground work implement 26 moves up and down. When a control signal is output from the controller 100 to the expansion solenoid or the contraction solenoid of the control valve 143 for the rolling cylinder 37 based on the set value of the horizontal adjustment dial 42 and the detected value of the slope sensor 43, the rolling cylinder 3
7 expands and contracts to change the left and right rolling angles of the ground work machine 26. Further, depending on the change of the steering angle sensor 128, as will be described later, the left and right reverse rotation clutches 78.
A control signal is sent to the clutch solenoid of the proportional control valve 147 for use to change the output speed to the left and right crawler type traveling devices C.

FIG. 10 shows the relationship between the magnitude of the clutch current output from the controller 100 (clutch cylinder pressure) and the rotation state of the crawler 16. For example, when the clutch current is 0 A in the forward traveling state, the clutch cylinder (oil chamber 95), the hydraulic pressure is 0 kg / cm ² , and as described above, the forward rotation clutch 77 is connected at full pressure by the bias of the spring 91, and the rotation of the input shaft 72 is directly transmitted to the output shaft 74. Then, the crawler 16 is rotationally driven in the forward direction. Forward / reverse switching device 7 from the controller 100
If the clutch current output to the clutch solenoid of No. 3 is gradually increased to increase the clutch cylinder pressure, the forward rotation clutch 77 slips when the clutch current is around 0.2 A, and the rotation speed of the crawler 16 in the forward direction is increased. Is reduced. When the clutch current increases to around 0.4 A, the clutch cylinder pressure becomes about 10 kg / cm ² and the forward rotation clutch 7
Both 7 and the reverse rotation clutch 78 maintain the disengaged state. Therefore, the rotation of the input shaft 72 is not transmitted to the output shaft 74 and the rear axle 11, and the crawler 16 is not rotationally driven.

From this state, when the clutch current is further increased to about 0.6 A, the reverse rotation clutch 78 is engaged while slipping, and the rotation of the input shaft 72 is reversed and transmitted to the output shaft. The crawler 16 starts rotating in the reverse direction in the half-clutch state. Then, the clutch current is set to 0.
When the pressure is increased to around 8 A, the clutch cylinder pressure becomes 20 kg / cm ^2, and the reverse rotation clutch 78 is connected at full pressure. Therefore, the crawler 16 is driven at high speed in the backward direction.

In this way, by changing the clutch current output from the controller 100, the clutch cylinder pressure of the forward / reverse rotation switching device 73 is increased / decreased, and the connection state of the forward rotation clutch 77 and the reverse rotation clutch 78 is continuously changed. The forward / reverse rotation switching device 73 continuously changes the driving torque between the forward rotation and the reverse rotation, and the crawler 16
The rotation direction and rotation speed of the can be continuously and arbitrarily adjusted.

Then, the steering operation (rotation operation) of the steering wheel 19 is detected by the steering angle sensor 128, and one of the forward / reverse switching device 73 of the forward / reverse switching device 73 is detected in accordance with the steering operation amount (change in the angle of steering). By controlling the clutch and decelerating the rotation of the crawler 16 on the inner side of the turning, it is possible to turn the vehicle body by giving a difference in rotation to the left and right crawlers 16, 16. On a relatively solid ground, the crawler 16 on the inside of the turn may be stopped or reversed to make the vehicle turn sharply, but if the rotation of the crawler 16 is locked during turning, the ground tends to be rough, so the normal direction on the inside of the turn is usually reversed. The clutch of the switching device 73 is slipped to decelerate the rotation of the crawler 16 on the inside of the turn, thereby slowly turning the vehicle body.

For example, in the forward traveling state, when the clutch current is 0 A, that is, the clutch cylinder pressure is 0 kg / cm ² , the left and right forward rotation clutches 77, 77 are connected at full pressure, and the left and right crawlers 16, 16 are both connected. Both are driven to rotate forward. When there is a turning operation of the steering wheel 19, one of the forward / reverse rotation switching devices 7 (the inside of the turning) is rotated.
The clutch current for the clutch solenoid No. 3 is gradually increased to increase the clutch cylinder pressure, and the forward rotation clutch 77 slips when the clutch current is around 0.2 A, and the one crawler 16 rotates in the forward direction. Is decreased, the left and right crawlers 16, 16 have a difference in rotation, and the vehicle body turns. By maintaining this clutch slipping state, the vehicle body can be gently turned (mild turn) without roughening the ground.

Further, when the clutch current to the clutch solenoid of the forward / reverse rotation switching device 73 on one side (inside the turning) is increased to around 0.4 A, the clutch cylinder pressure becomes about 10 kg / cm ² , and the one forward rotation clutch 77. Both the reverse rotation clutch 78 and the reverse rotation clutch 78 are disengaged. For this reason, the rotation of the input shaft 72 is not transmitted to the one rear axle 11, the rotation of the crawler 16 on the inside of the turn is stopped, the turning radius is reduced, and the vehicle body can be turned (lock turn).

Further, when the clutch current to the clutch solenoid of the forward / reverse rotation switching device 73 on one side (inside the turning) is increased to around 0.8 A, the clutch cylinder pressure becomes 20 kg / cm ² and one for reverse rotation is used. Clutch 78 engages at full pressure. Therefore, the rotation of the input shaft 72 is reversed and transmitted to the output shaft 74, and the one rear axle 11
Is reversed, and the crawler 16 on the inside of the turn is driven to rotate in the reverse direction. Therefore, the left and right crawlers 16 and 16 rotate in mutually opposite directions, and the turning radius becomes the minimum, so that the vehicle body can make a super turning turn (spin turn).

11 and 12 show a steering unit 22 in which the steering handle shaft 20 is rotatably supported by a cylindrical handle post 150. A male screw portion 20 a is provided on the steering handle shaft 20 in the handle post 150.
A rotary piece 151 having a female screw portion that is screwed into 0a is provided. A slit 150a is opened at one side of the handle post 150, and an arm 151a fixed to one side of the rotary top 151 is projected to the outside from the slit 150a. The steering handle shaft 2
Rotating piece 1 that is screwed into the male screw portion 20a when 0 rotates
51 also tries to rotate, but the arm 151a of the rotating top
Is locked in the slit 150a of the handle post to prevent the rotation of the rotary piece 151, and the rotary piece 151 moves up and down along the steering handle shaft 20. The rotation piece 151 constitutes a rotation detection unit that operates in conjunction with the rotation operation of the steering handle shaft 20.

On one side of the handle post 150,
A bracket 152 is provided outside the slit 150a, and a steering angle sensor 128, which is a potentiometer, is attached to the bracket 152 as a sensor for detecting the operating position of the rotation detector. The tip end of the arm 151a of the rotating piece engages with the sensor arm 129 of the steering angle sensor 128. Therefore, the vertical movement of the rotary top 151, that is, the rotation angle of the steering handle shaft 20 is detected by the steering angle sensor 128.

A rotary cylinder 153 having a half-divided shape is provided at the lower part of the steering handle shaft 20 protruding below the handle post 150 so as to rotate integrally with the steering handle shaft 20, and inside the rotary cylinder 153. Further, a torsion coil spring 154 is housed as a biasing means for biasing the steering handle shaft 20 to the neutral position. Further, on the steering handle shaft 20, a rotating plate 155 is fixedly provided below the torsion coil spring 154,
When the steering handle shaft 20 is in the neutral position, the protrusion 155a of the rotary plate 155 is formed so as to be located at the center of the front surface. Steering handle shaft 2
Since the steering unit 22 is configured by integrally subassembling 0 and the handle post 150 and the like, the assembling work can be easily performed.

Here, the steering handle shaft 20
A brake material is provided around the periphery of the brake post 150 to brake the rotation of the handle post 150. For example, a lining 156 is provided near the upper end of the steering handle shaft 20, and a spring 157 is attached to the upper part of the lining 156 to press the lining 156. Therefore, the pressing force of the spring 157 causes the lining 156 to move to the handle post 15
It is possible to prevent the rotation of the steering handle shaft 20 and the handle post 150 from being pressed against the upper end of the steering wheel 0 to prevent the steering handle 19 from rotating excessively. The lining 156 may be attached at the lower end of the steering handle shaft 20 instead of the upper end. Although not shown, the rotary plate 1
A lining may be provided below 55.

When the steering handle 19 is rotated, the steering handle shaft 20 is integrated with the steering handle 19.
Rotates, and as described above, the steering angle sensor 128 detects the vertical movement of the rotating top 151. This detection signal is sent to the controller 100, and the controller 1
At 00, the rotational operation angle of the steering wheel 19 is calculated. Then, the outputs of the left and right proportional control valves 147 to the clutch solenoids are controlled according to the calculated rotation operation angle, and the forward / reverse rotation switching device 7 on the inside of the turn is controlled.
Activate 3. Thus, the driving speed of the crawler 16 on the inside of the turn is reduced, and the vehicle body turns.

The rotation of the steering handle shaft 20 causes the rotating plate 155 to rotate integrally therewith, and the protrusion 155a abuts either the left or right stopper 158 to stop the rotation of the steering handle shaft 20. That is, the steering wheel shaft 20 is moved from the neutral position to the left and right by 1 respectively.
It has a rotation range of 80 ° (total rotation angle of 360 °). When the rotating operation of the steering handle 19 is stopped, the steering handle shaft 20 is returned by the bias of the torsion coil spring 154, and the steering handle 19 is returned to the neutral position.

Thus, as shown in FIG. 13, the steering wheel 19 has a rotation range of 180 ° to the left and right (total rotation angle of 360 °). For example, when the steering wheel is steered to the left from the neutral position, The play is about 20 °, the mild turn is about 100 °, the rock turn is about 30 °, and the spin turn is about 30 °. The steering operation angle sensor 128 detects the steering operation amount of the steering handle 19 (steering wheel operation angle = rotation angle), and the clutch current to the clutch solenoid of the forward / reverse rotation switching device 73 is detected according to the steering operation amount. Adjust the clutch cylinder pressure (hydraulic piston 9
3) operating pressure).

FIG. 14 shows a frame on which the steering handle shaft 20, the handle post 150 and the like are mounted, and a steering handle column 21 is provided upright on the rear portion of the front frame 160. The mission case 23 is connected to the rear portion of the mid frame 161. Although illustration is omitted, the steering unit 22 is mounted on the steering handle column 21. Incidentally, the steering unit 22 is sub-assembled by an assembly, and as shown in FIG. 15, it can be assembled by replacing the mechanical steering device 162.

As shown in FIG. 16, the handle post 150 is attached to a bracket 165, and the bracket 165 is fixed to the steering handle column 21 with two bolts 166 and 167. The upper bolt 166 is inserted into the long hole 168.
When 6 is loosened, the bracket 165 swings back and forth around the lower bolt 167. Therefore, the upright angle of the steering handle shaft 20 can be changed integrally with the steering unit 22, and the tilt handle can be constructed at low cost. Although not shown, the bracket 165 is formed with a vertically long hole to form bolts 166 and 167.
If the bolts 166 and 167 are fastened, the steering handle shaft 20 can be moved up and down integrally with the steering unit 22 by loosening both bolts 166 and 167, and a telescopic handle can be constructed at low cost.

[0057]

[Table 1] The lock turn and spin turn are selected according to the conditions shown in Table 1. The spin turn switch 11 described above
No. 4 is provided near the driver's seat 18 at a position where the operator can easily operate it, and can always be turned on and off while the ignition key is energized. When the spin turn switch 114 is off, the spin turn (denoted as S turn) is not executed under any condition.
Further, when the auxiliary shift is in the high speed (H) position, the spin turn is not executed even if the spin turn switch 114 is on. When the sub-shift is in the high speed (H) position and the main shift is in the 2nd or 3rd position, the spin turn and the lock turn (denoted as R turn) are not executed and the mild turn (denoted as M turn). ) Is executed only.

Here, when the operator cancels the steering operation of the steering handle 19, the steering handle 19 may overshoot the neutral position and go over to the opposite side. When that happens, the steering angle sensor 12
When 8 detects a steering operation in the opposite direction and outputs an operation signal to the clutch of the forward / reverse rotation switching device 73 on the opposite side, the forward rotation clutch 77 on the opposite side starts slipping, so that the vehicle body swings left and right for a moment. It makes the ride uncomfortable. In order to prevent this, the controller 100 temporarily stops the operation signal output to the clutch of the forward / reverse rotation switching device 73 on the opposite side.

FIG. 17 is a flow chart showing the control procedure when the steering operation is canceled. When the operator cancels the steering operation, the controller 100 calculates the change speed of the steering angle (step 101). Then, when the steering handle 19 tries to return to the neutral position by the neutral position returning mechanism 138 and exceeds the neutral position on the opposite side (step 102), it is determined whether or not the changing speed of the steering angle is decreasing. (Step 10
3). When the changing speed of the steering angle is decreasing, it can be determined that the steering handle 19 has exceeded the neutral position to the opposite side by inertia, such as when the operator releases the steering handle 19. In that case, the controller 100 restrains the operation signal output to the clutch of the forward / reverse rotation switching device 73 on the opposite side for a predetermined time (step).
104). The restraint time is set based on the time required for the steering wheel 19 to return to the neutral position from the stationary position, but is set within 0.5 seconds at maximum. In this way, shake of the vehicle body due to excessive movement of the steering wheel 19 is suppressed, and ride comfort can be improved.

On the other hand, in step 103, when the changing speed of the steering angle is in the constant speed state or in the increasing state, the operator operates the steering wheel 1.
It can be judged that 9 is intentionally operated to the opposite side. In that case, the controller 100 immediately outputs an operation signal to the clutch of the forward / reverse rotation switching device 73 on the opposite side (step 105). Thus, the vehicle body can be adjusted to a new turning state according to the intentional steering operation of the operator.

Further, in step 104, even when the operation output to the opposite side is being restrained, as shown in FIG. 18, the steering angle exceeds the neutral position to the opposite side and is equal to or more than a certain value (for example, neutral). When rotated from the position by 30 to 40 ° or more), it is determined that the operator intentionally operates the steering handle 19 at the deceleration speed. In that case, the controller 100 outputs an operation signal to the clutch of the forward / reverse rotation switching device 73 on the opposite side. Therefore,
Even if the changing speed of the steering angle is decreasing due to an artificial operation, the turning operation can be reliably performed.

Therefore, when the difference in rotation between the left and right crawlers 16 and 16 becomes large with respect to the change in the steering angle and the crawler 16 on one side slips, the clutch pressure on the idling side is increased. Is controlled to lower the rotation of the crawler 16 once and secure the bite of the crawler 16 with respect to the ground. Alternatively, a predetermined clutch current may be determined for a change in the steering angle, and a high current value may be sent with a time lag to improve response, and control may be performed to increase the torque at a low pressure value. Good.

Here, the clutch current for the clutch solenoid of the forward / reverse rotation switching device 73 has a basic current value corresponding to the steering disengagement angle as a target, and this is not in a safety mode. Pass the current value through the control valve. When the steering handle 19 is operated, the clutch current also follows and changes, but it does not have a time constant and changes immediately. Then, as will be described later, turning control for avoiding a lock turn and a spin turn is performed.

As shown in FIG. 19, in response to the steering operation of the steering wheel 19, the controller 100 outputs a clutch current in a pulsed manner, and in order to improve the responsiveness immediately after the start of the steering operation, the controller 100 momentarily moves to the clutch cylinder. (Time T ₂ ) Apply high initial pressure P ₁ . After that, the clutch cylinder control pressure P ₂ is output to obtain the turning radius according to the steering angle. Then, when the predetermined clutch output ON time T ₁ has elapsed, the controller 10
In the case of 0, the clutch current is momentarily cut off to turn off the clutch, and the clutch current is immediately applied to apply an intermediate pressure, that is, the periodic pressure P ₃
Is added for a time T _{3 to} turn on the clutch.

As described above, the clutch can be held in a constant slip state by reconnecting the clutch at a constant cycle (time T ₁ ) instead of continuously applying a constant clutch pressure. Here, the optimum initial pressure P ₁ obtained from the experimental data is 24 kg / cm ² , and the cyclic pressure P ₃ is 16 kg / cm ² . The clutch output ON time T ₁ is 500 msec, and the initial pressure holding time T ₂ is 150 mse.
c, the periodic pressure holding time T ₃ is 20 msec. Further, the control pressure P ₂ is selected from four types of characteristic curves under the following conditions.

The amount of change is detected from the steering operation amount of the steering wheel 19, and the larger the amount of change, the more the initial pressure P ₁ is corrected as shown by the chain double-dashed line in FIG.

[0067]

[Table 2] When the spin turn switch 114 is on,
If the auxiliary gear shift is at the low speed (L) position, the control pressure P ₂ changes according to the characteristic curve as shown in FIG. In this case, the control of the cyclic pressure P ₃ is not performed between P120 and P180, and when the spin turn is started, the clutch cylinder pressure is held and the disks 78a and 78b of the reverse rotation clutch 78 are continuously pressed.
Further, when the sub-shift is in the high speed (H) position, the control pressure P ₂ has the characteristic shown in FIG. 20C when the main shift is the first speed, and when the main shift is the second speed or the third speed, the control pressure P ₂ has the characteristic shown in FIG. The characteristics shown in (d) are obtained. That is, even if the spin turn switch 114 is on, the spin turn is not performed in the high-speed traveling state, and the mild turn is limited.

On the other hand, the spin turn switch 1
In the state where 14 is off, if the auxiliary gear shift is at the low speed (L) position, the control pressure P ₂ changes according to the characteristic curve as shown in FIG. 20 (b) regardless of the main gear shift position. . If the sub gear shift is at the high speed (H) position, the control pressure P ₂ is shown in FIG. 20 (c) when the main gear shift is the first gear, similarly to the state where the spin turn switch 114 is on. When the main shift is the second speed or the third speed,
The characteristics shown in (d) are obtained.

The pressure data of P _{1 to} P ₃ , the time data of T _{1 to} T _{3 and} the data of each point of P20, P120 and P180 are set in advance, and each data is rewritten by a checker. It is possible. Next, the control procedure when an abnormality occurs in the steering angle sensor 128 that detects the steering operation amount of the steering wheel 19 will be described with reference to the flowchart of FIG. First, the controller 100 reads the state of each sensor and switch (step 201). Here, the steering angle sensor 128
Is set to θ, the sensor value of the left crawler rotation sensor 107 is set to R _L, and the sensor value of the right crawler rotation sensor 107 is set to R _R. Now, when the steering wheel 19 is in the neutral position, the steering angle sensor 12
8 sensor value theta = 0 ° next (step 202), when accordingly, the vehicle body if the sensor value R _R of the sensor values R _L and the right crawler speed sensor 107 of the left crawler speed sensor 107 coincides straight It can be determined that the vehicle is running (step 203). Therefore, the steering angle sensor 1
There is no error in the assembly position of 28 and it is operating normally.

Here, the steering angle sensor 128
A sensor value theta = 0 ° Despite for, if the sensor value R _L of each of the right and left crawlers rotation sensor 107 and the R _R do not match, there is an error in the position L of assembling the steering angle sensor 128 Alternatively, the controller 100 determines that an abnormality such as a failure has occurred, and the controller 100 notifies the neutral position shift by lighting or blinking a lamp, or buzzing a buzzer (step 204).

Then, the engine speed sensor 112
It is determined whether the engine 46 has not been started (step 205) based on the detection signal of (1), and when the engine has not been started, the controller 100 sends a starter relay signal to the starter relay even if the operator tries to start the engine 46. The engine start is restrained without sending a control signal (step 206). This prevents a danger because the turning motion of the vehicle body is not accurately performed against the steering operation of the steering handle 19 against the intention of the operator when the steering angle sensor 128 is abnormal. Therefore, the engine 46 is not started. Further, for example, a check switch (not shown) is turned on to turn on the controller 10
When the check mode for checking the state of 0 is set, the steering operation is not performed even if the steering wheel 19 is rotated in this state, so that the vehicle cannot be turned even if the vehicle body is run. Therefore, during the check mode, the engine start is restrained to improve safety.

On the other hand, when an abnormality occurs in the steering angle sensor 128 after the engine is started, the controller 100 sends a control signal to the governor adjusting actuator to cut off the fuel, stop the rotation of the engine 46, and run the vehicle body. Is stopped (step 207). in this way,
When an abnormality occurs in the steering angle sensor 128 during traveling of the vehicle body, the turning operation of the vehicle body is not accurately performed against the steering operation of the steering handle 19 against the operator's intention, which is dangerous. To prevent this, the engine 46 is immediately stopped to ensure safety.

When an abnormality occurs in the steering angle sensor 128 after the engine is started, the controller 100 may correct the operation signals to the clutch solenoids of the left and right proportional control valves 147 for the forward / reverse switching devices 73. Good. Controller 1
00 constantly detects the signal of the left and right crawler rotation sensor 107 by interruption, and internally calculates the output rotation speed to the crawler type traveling device C. On the other hand, if the target rotation ratio curve corresponding to the sensor value of the steering angle sensor 128 is held and the measured rotation speed ratio is far from this, the correction value weighted by the condition is displayed each time. With more reference, the target clutch pressure is corrected. That is, the clutch current is corrected as an interrupt process when the vehicle is traveling straight in a normal operation. The clutch current can be corrected in the check mode described above.
Thus, the steering performance of the vehicle body can be improved.

Also, when the engine of the vehicle is started, the sensor value of the steering angle sensor 128 may be input and this sensor value may be set as the neutral position of the steering wheel 19. Here, the treatment when an abnormality occurs in each sensor and the blinking of the lamp will be described according to Table 3.

[0075]

[Table 3] For example, when an abnormality occurs in the steering angle sensor 128, the cause of the abnormality may be a sensor disconnection or a short circuit. Then, as a measure when an abnormality occurs, the operation signal output to the proportional control valve 147 for the forward / reverse rotation switching device 73 is prohibited and the abnormality is notified by blinking a monitor lamp. When an abnormality occurs in either the left or right crawler rotation sensor 107, a defect or disconnection of the sensor itself is cited as an abnormality factor, and the turning control is not executed at that time. On the other hand, when an abnormality occurs in the lift arm angle sensor 33, disconnection or short circuit of the sensor can be cited as the cause of the abnormality. In this case, no action is taken when an abnormality occurs, the monitor lamp is lit to notify the abnormality, and the turning control is continued in order to distinguish it from the abnormality of the steering angle sensor 128 or the crawler rotation sensor 107.

Further, the abnormality determination of the crawler rotation sensor 107 is carried out when the steering wheel 19 is in the neutral position (within ± 20 °), the output rotation speed is 10 rpm or more, and
When the left / right output rotation ratio is 0.5 or less for 10 seconds or more, it is determined to be abnormal. After that, the turning control pressure correction is fixed to zero. However, the target pressure corresponding to the steering angle is output. That is, the feedback by the crawler rotation sensor 107 is not performed, and the steering wheel 1
It is possible to turn 9 in the direction of rotation. Regarding the abnormality of the crawler rotation sensor 107, it is assumed that the error flag is kept on during the energization and is cleared by turning off the power.

On the other hand, when an abnormality occurs in the steering angle sensor 128, the horizontal adjustment dial 42 and the like used for the left and right rolling control are used to perform the steering operation of the vehicle body. You can also When the steering angle sensor 128 fails, it is dangerous that the vehicle body becomes unsteerable. In that case, the clutch of the left / right forward / reverse switching device 73 is operated by operating the horizontal adjustment dial 42 or the vehicle body tilt up / down switch. Adjust the clutch current to the solenoid to steer the vehicle.

As described above, since the steering of the vehicle body can be operated by the plurality of operating portions, the unsteerable state can be avoided. When an abnormality occurs in the steering angle sensor 128, the turn signal lever switch 11 is used instead of the operation of the horizontal adjustment dial 42 and the like.
5 may be used to perform a steering operation of the vehicle body. In that case, if the turn signal lever switch 115 is operated to the right, the vehicle body is steered to the right, and the turn signal lever switch 115
When is operated to the left, the vehicle body is steered to the left.

Further, when the proportional control valve 147 for sending the pressure oil to the reverse rotation clutch 78 fails, the pressure oil is not supplied to the reverse rotation clutch 78, and the vehicle body becomes inoperable. As shown in FIG. 8, the rolling cylinder 3
The oil passages L ₁ and L ₂ of _No. 7 are formed so that the oil passages can be connected or disconnected by the connectors 144 and 145, and the oil passages L ₅ and L _{6 of} the left and right reverse clutches 78 and 78 are also connected to the connectors 148 and 149. It is formed so that the oil passage can be connected or disconnected. Therefore, when the proportional control valve 147 for the reverse clutch 78 fails, the connectors 144, 145, 148, 149 are temporarily disconnected, and the oil passages L ₅ , L ₆ of the left and right reverse clutches 78, 78 are disconnected. By connecting to the connectors 144 and 145, the control valve 143 for the rolling cylinder 37 is switched to send pressure oil to the left and right reverse clutches 78, 78. As described above, by configuring the steering of the vehicle body so as to be able to be operated by using the plurality of hydraulic circuits, it is possible to avoid the unsteerable state.

Now, the rolling control device of the ground work machine 26 connected to the crawler type tractor 10 will be described. If the ground work implement 26 such as a rotary is rolled leftward or rightward at the work implement lowermost position depending on the type of work implement or the link attachment position, the ground work implement 26 may come into contact with the rear end of the crawler 16 and be damaged. is there. Therefore, when the ground work implement 26 descends below a predetermined height,
By stopping or reducing the correction of the left and right rolling postures of the ground work implement 26, the crawler 16 and the ground work implement 26 are prevented from interfering with each other.

For example, the state of rolling control is changed according to the detection value of the lift arm angle sensor 33 as shown in the flowchart of FIG. 22 and Table 4.

[0082]

[Table 4] First, load each sensor and switch (step 30
1) Based on the detection value of the lift arm angle sensor 33, the controller 100 determines whether the vehicle body is in the traveling area, the working area, or the restricted area (step 302). When the detection value of the lift arm angle sensor 33 is within the range of (-α to -150) bits, the vehicle is regarded as the working area (step 304), and the ground work implement 26 is set by the horizontal adjustment dial 41. In order to maintain the set horizontal state, the controller 100 outputs a control signal to the expansion solenoid or the contraction solenoid of the rolling cylinder 37 control valve 143. Manual operation is possible up to the stroke end, and parallel control of the machine is also possible.

On the other hand, when the value detected by the lift arm angle sensor 33 is in the range of (MAX to -α) bits, it is considered that the vehicle is in the traveling range when the height of the ground work implement 26 is near the highest position. (Step 303), the ground work machine 26 is maintained parallel to the machine body. Also in the case of the traveling area, similar to the above-mentioned work area, manual operation is possible up to the stroke end, and control of the machine body parallel is also possible.

On the other hand, the lift arm angle sensor 33
When the detected value of is in the range of (-150 to MIN) bits,
When the height of the ground work implement 26 is in the vicinity of the lowest position and the vehicle is considered to be in the restricted area (step 305), the control of the rolling posture of the ground work implement 26 is restricted. Then, this limit amount is increased as the ground work implement 26 is lowered. That is,
When the ground work implement 26 is descending below a predetermined height,
Limit the swing angle to ± 3 ° (approximately ± 25 bits) or less. When the output to the rolling cylinder control valve 143 exceeds this, the output in that direction is prohibited. Further, when the lift arm 29 descends even when the ground work implement 26 is inclined at 3 ° or more, the swing of the ground work implement 26 is limited within 3 ° at that time. Then, as the position of the ground work implement 26 becomes lower, the limit amount is increased such that the swing angle is ± 2 ° or the swing angle is ± 1 °, and the crawler 1 is increased.
Avoid interference with 6.

For manual operation in the restricted area, when the ground work implement 26 is tilted at 3 ° or more, the ground work implement 26 is swung until it is within 3 °. Even if the manual switch is operated thereafter, the swing is allowed within the range of 3 °. In this way, by restraining the ground work implement 26 from swinging near the lowest position, it is possible to prevent interference with the crawler 16. That is, the balance of the machine is prioritized over the horizontal accuracy at the lowest position where the frequency of actual occurrence is low.

Here, the steering angle sensor 128
When it is determined that the tractor 10 has begun to turn from the change in the detected value of, the controller 100 outputs a control signal to the lift solenoid of the lift cylinder control valve 142 to raise the ground work implement 26 to the non-working height. The ground work implement 26 is prevented from being dragged. When the turning is completed, the ground work implement 26 is lowered by operating the manual switch. However, the manual operation of the operator is complicated, and improvement has been demanded. Therefore, as described above with reference to FIGS. 5 and 9, the rotation speed of the output shaft 74 is detected by the rotation sensor 107 provided in the rear axle case 47, and the controller 100 calculates the left / right rotation ratio. The ground work implement 26 is moved up and down in accordance with the turning motion of the vehicle body.

As shown in FIG. 23, a rotation detecting gear 106 is provided between the two-step planetary gear mechanism 75 and the one-step planetary gear mechanism 101, and the rotation speed detecting gear 10 is provided.
6, the non-contact type rotation sensor 107 is arranged in the vicinity,
The rotation number of the output shaft 74 is pulse-counted, and the controller 100 calculates the left-right rotation ratio. When the operator repeats adjacent cultivating work in the field several times, the controller 100 inputs the lift cylinder control valve 142 up signal at the start of turning to the lift cylinder control valve 142 down signal at the end of turning. The number of rotations of the output shaft 74 on the outer side of the turning until the input is stored. Then, the average value of each of the right turn and the left turn is calculated, and thereafter, at the time of turning in the adjacent tilling work, the change in the left and right rotation ratio is read, and the controller 100 causes the ground work machine 26 to raise the signal. And the lowering signal is output automatically.

Therefore, by turning on the automatic hydraulic pressure lowering switch 118 provided in the vicinity of the monitor panel 117, when the operator turns the steering handle 19 at the time of turning in the adjacent plowing work, the turning start is started. At the same time, a hydraulic pressure increase signal is output to raise the ground work implement 26, and a hydraulic pressure decrease signal is output at the end of turning,
The ground work machine 26 descends. And the monitor panel 11
7, the monitor lamp 117a lights up or blinks depending on the situation. For example, if the automatic hydraulic pressure lowering switch 118 is off, the monitor lamp 117a is turned off. On the other hand, if the automatic hydraulic pressure lowering switch 118 is on, the monitor lamp 117a is in a blinking state, and the controller 10
0 indicates that the left / right rotation sensor 107 performs pulse counting to indicate that automatic control execution is in preparation. Then, when the automatic hydraulic pressure lowering signal is output from the controller 100, the monitor lamp 117a is turned on to display that the automatic control is being executed. Thus, the operation of the operator at the time of adjacent tillage work is simplified.

Here, if the output rotational speed of the left and right crawler type traveling devices C deviates from the target value, the controller 10
It is necessary to correct the signal output from 0 to the solenoid of the proportional control valve 147. Controller 100
Constantly detects the signal of the rotation sensor 107 by interruption and internally calculates the rotation speed. On the other hand, if the target rotation ratio curve corresponding to the turning angle of the steering wheel 19 is held and the measured rotation speed ratio is far from this, the correction value weighted by the degree and the condition is referred to from the table. To correct the target pressure. The purpose of this control is to prevent the operator from making a rock turn in the mild turn area while trying to make a gentle turn. Therefore, it is not possible to expect the effect of accurately following the target turning diameter over the entire turning angle of the steering wheel 19. This is because the steering angle that determines the target value is changed instantaneously and frequently by the operator's will, so there is a limit in adapting the general concept of feedback, and it can be realized only with rough control. Imagine that.

The target pressure curve output from the controller 100 to the solenoid of the proportional control valve 147 varies depending on the vehicle speed. As shown in FIGS. 1 (a) to 1 (c), the target pressure curve (solid line ), Set upper limit pressure curve (dashed line), set lower limit pressure curve (dashed line), and target rotation ratio curve (dotted line). For example, when the shift position is low, a target pressure curve as shown in FIG. 9A is set, and the lock turn is executed when the steering angle becomes about 120 ° or more. The spin turn switch 114 described above
If is on, the steering angle is 150 °.
Perform a spin turn when is exceeded.

On the other hand, when the shift position is the high first speed, the target pressure curve as shown in FIG. 9B is set, and in this case, the spin turn is executed regardless of whether the spin turn switch 114 is on or off. Instead, the lock turn is executed when the steering angle reaches about 180 °.
Further, when the shift position is in the high 2nd speed or the high 3rd speed, the target pressure curve as shown in FIG. 7C is set, and the slippage of the clutch is maintained even if the steering angle is increased to maintain the vehicle body. To make a mild turn.

Then, a pressure correction value is added to this target pressure curve. This correction value has upper and lower limits of the correction width separately, and when the calculated result exceeds the correction value, it is replaced with this limit value. The correction range is gradually narrowed around 20 ° and 120 ° or more, but it is thought that if this value is suddenly set to 0, a sensational shock will occur. The correction limit is always valid regardless of the 0.3 second cycle described later. Therefore, the steering wheel 19 is suddenly turned greatly,
When the correction value is added as it is and the limit is exceeded, the limit value shall be immediately replaced regardless of the cycle. That is, the pressure value does not deviate from this range in any case.

As the target pressure curve, a non-linear pressure curve is set so that the pressure change becomes large near neutral and the pressure change becomes smaller as the steering wheel 19 is turned off. This is because when it is desired to proportionally change the rotation ratio of the axle, that is, the turning diameter, with respect to the steering amount of the steering wheel 19, a simple linear pressure curve does not make sense. In the case of a linear curve, the amount of steering turning is small near the straight line for the same operating angle, and the turning angle is extremely close near the lock turn, so the actual distribution of the turning angle is biased. This point is also proved by the test results.

Further, with respect to the target pressure curve (solid line), the set upper limit pressure curve (dashed line), which is the correction limit on the pressure increasing side, and the set lower limit pressure curve (dashed line), which is the correction limit on the pressure reducing side, are The correction limit pressure on the side where the rotation difference of the crawler is large is set smaller than the correction limit pressure on the side where the rotation difference is small. That is, the difference H ₂ between the set upper limit pressure curve (dashed line) and the target pressure curve (solid line), the set lower limit pressure curve (dashed line) and the target pressure curve (solid line)
And the difference H ₃ is compared, the setting is made so that H ₂ <H ₃ .

Regarding the correction timing and the correction value, the pressure correction is performed at a cycle of 0.3 seconds. Controller 100
Checks the number of revolutions in this cycle, and if there is a deviation, corrects with the values in Table 5 and Table 6. The distribution in this table is intended to be corrected as it approaches zero rotation and as the deviation from the target rotation ratio increases. This correction value is added up to the correction limit in the preceding paragraph.

[0096]

[Table 5]

[0097]

[Table 6] Table 5 shows a correction table when the shift position is in the low speed or high first speed or in reverse, and Table 6 shows the correction table when the shift position is high 2
7 shows a correction table when the vehicle is in high speed or high 3rd speed. The cycle can be rewritten by the checker, and the change of the table value is dealt with by rewriting the program itself.
Regarding the clearness of the correction value, it is cleared (0) if any one of the following conditions is met. (1) When the steering is set to 20 ° or less, that is, when the vehicle goes straight. (2) When turned to the spin turn range. (3) When a shift is changed. This means that each time the steering wheel is turned, the correction is started from zero, and the correction value is not stored and used for the next turn.

For example, if the steering handle 19 is turned to the left by 100 ° while working at low speed,
As shown in the graph of (a), the target pressure is 17 kg / cm ² ,
The target rotation ratio is 0.2. The controller 100 immediately supplies the left proportional control valve 147 with an output corresponding to this pressure. The number of rotations of the axle is read after 0.3 seconds. If the left is 70 rpm and the right is 100 rpm, the rotation ratio is 70/100 and 0.7. Therefore, the deviation is 0.7-0.2 = 0.5. Referring to this from Table 5, the correction value is +1 kg / cm ² . Therefore, the proportional control valve 147 has 17
It outputs 18kg / cm ² at +1.

Further, after 0.3 seconds, the judgment is made again and if it is 50
When the speed is reduced to rpm, the rotation ratio is 0.5 at 50/100, and the shift is 0.5-0.2 = 0.3. Accordingly, the correction value is + 0.5 kg / cm ^2, a 18.5 kg / cm ² when added to the 18 kg / cm ^2. Also, the steering wheel 1
If 9 is returned to 50 °, the correction value immediately before is 18.
Since 5-17 = + 1.5, 1.5 is corrected to 15 to obtain 16.5 kg / cm ² . In this way, the current correction value is kept alive, and the progress such as whether the limiter of the upper and lower limits is caught or how many corrections are accumulated in the past is not dragged.

The present invention can be modified in various ways without departing from the spirit of the present invention, and it goes without saying that the present invention extends to such modifications.

[Brief description of drawings]

The figure shows an embodiment of the present invention.

FIG. 1A is a graph showing a relationship between a steering angle, a left / right rotation ratio, and a clutch pressure at a low speed position.
(B) is a graph showing the relationship between the steering angle, the left / right rotation ratio, and the clutch pressure at the high first speed position. (A)
Is a graph showing the relationship between the steering angle, the left / right rotation ratio, and the clutch pressure at high and second speed positions.

FIG. 2 is a side view of a crawler type tractor.

FIG. 3 is a rear view of the crawler type tractor.

FIG. 4 is a sectional view showing the inside of a mission case.

FIG. 5 is a cross-sectional view showing the inside of a rear axle case.

6A is a sectional view taken along line AA of FIG. 5, and FIG. 6B is FIG.
BB line sectional drawing.

FIG. 7 is an explanatory diagram showing a power transmission path.

FIG. 8 is a hydraulic circuit diagram.

FIG. 9 is a block diagram of a control system.

FIG. 10 is a graph showing the relationship between clutch cylinder pressure and crawler rotation state.

FIG. 11 is a vertical sectional side view of the steering unit.

FIG. 12 shows a steering unit, (a) is a plan view, (b) is a front view, and (c) is a bottom view.

FIG. 13 is an explanatory diagram illustrating a turning state with respect to a rotation position of a steering wheel.

FIG. 14 is a perspective view of a frame.

FIG. 15 is an exploded perspective view of a mechanical steering device.

FIG. 16 is a side view of the tilt handle.

FIG. 17 is a flowchart showing a control procedure when steering operation is canceled.

FIG. 18 is a plan view of a tractor for explaining steering control.

FIG. 19 is a graph showing a change in clutch cylinder pressure with respect to a steering handle steering operation.

20A to 20D are graphs showing the characteristics of the control pressure that changes according to the spin turn switch and each shift position.

FIG. 21 is a flowchart illustrating a control procedure when an abnormality occurs in the steering angle sensor.

FIG. 22 is a flowchart of rolling control.

FIG. 23 is an explanatory diagram showing a connection configuration of a rotation sensor and an automatic hydraulic pressure lowering switch.

[Explanation of symbols]

10 tractors 19 steering wheel 73 Forward / reverse switching device 100 controller 128 steering angle sensor 147 proportional control valve C-crawler type traveling device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masayuki Takahashi             No. 1 Yakura, Tobe-cho, Iyo-gun, Ehime Prefecture             Technology Department Co., Ltd. (72) Inventor Hitoshi Ueji             No. 1 Yakura, Tobe-cho, Iyo-gun, Ehime Prefecture             Technology Department Co., Ltd. F term (reference) 3D052 AA02 AA12 BB02 BB03 BB08                       CC01 EE01 FF01 GG03 HH03                       JJ14 JJ23 JJ25 JJ37

Claims (6)

[Claims] 1. A transmission mechanism that comprises crawler type traveling devices C on the left and right of a vehicle body, and changes the pressure of the multi-plate clutch by the operation of an actuator 147 to change the output rotational speed to the crawler type traveling devices C. 73 is arranged on each of the left and right sides, a sensor 107 for detecting the output rotational speed is installed on each of the left and right sides of the transmission mechanism 73, and a turning angle sensor 128 for detecting the steering operation amount of the steering wheel 19 is provided. In the crawler type working vehicle in which the steering state of the vehicle body is adjustable by outputting an operation signal to the actuator 147 according to the detection value of the sensor 128, the output rotation to the left and right crawler type traveling devices C is performed. The rotational speed ratio is detected from the rotational speed, and when the detected rotational speed ratio deviates from the target rotational speed ratio corresponding to the detection value of the turning angle sensor 128, A steering control device for a crawler-type work vehicle, comprising: a control unit 100 that corrects the pressure of the multi-plate clutch based on a correction value that is set so as to obtain a target rotation ratio. 2. The crawler type work vehicle according to claim 1, wherein the correction value is a table correction value defined for the target rotation speed ratio according to a difference between the target rotation speed ratio and the detected rotation speed ratio. Steering control device. 3. In the pressure correction for the multi-disc clutch, correction limit pressures are set on the pressure increase side and the pressure decrease side of the target pressure, respectively, and the correction limit pressures on the pressure increase side and the pressure decrease side are set for the left and right crawlers. 3. The steering control device for a crawler type work vehicle according to claim 1, wherein the correction limit pressure on the side where the rotation difference is large is set smaller than the correction limit pressure on the side where the rotation difference is small. 4. The table correction value is determined for each vehicle speed, and a control unit 100 for correcting the vehicle body to make a gentle turn, a turning turn, and a super turning turn in a low speed range as the detection value of the turning angle sensor 128 increases. The steering control device for the crawler type work vehicle according to claim 1, 2, or 3. 5. The control unit 100 according to claim 1, 2, 3 or 4, further comprising: a control unit 100 for correcting the vehicle body to slowly turn to a turning turn in a medium speed range with an increase in the detection value of the turning angle sensor 128. Steering control device for crawler type work vehicle. 6. A control unit 1 for correcting the vehicle body up to a gentle turn in a high speed range as the detection value of the turning angle sensor 128 increases.
The steering control device for a crawler type work vehicle according to claim 1, 2, 3, 4 or 5, further comprising: 00.