JPH0986432A - Steering turn control device for work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the safety of a steering turn by switching the spin turn mode to the brake turn mode when the reverse state is detected during the work in the spin turn mode in a work vehicle capable of switching the turn mode to the brake turn mode, slow turn mode, and spin turn mode. SOLUTION: When a controller 65 is to switch the turn mode to the spin turn mode via a turn mode switching lever, a steering clutch is disengaged by the tilting action of a power steering lever to the right or left via a steering cylinder. Whether a turn executing switch 59 is turned on or not is checked. If yes, whether the reverse state of a vehicle body by the operation of a main shift lever is detected by a reverse detecting means 3 or not is checked. If the detection of the reverse state is yes, a turn clutch solenoid valve 67 is turned off by an automatic switching means 4 stored in the controller 65, and the spin turn mode is switched to the brake turn mode for a brake turn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering turning control device for a working vehicle, and in a working vehicle such as a combine or a tractor, when turning, the turning modes of brake turning, gentle turning, and spin turning are appropriately switched to perform steering turning. It can be used for things to do.

[0002]

2. Description of the Related Art When an operator makes a steering turn in a headland at the end of a field at the time of working, a brake turning mode in which a normal turning is performed by brake braking on the steering side. And a slow swing mode in which the steering side decelerates and rotates to make a gentle large turn, and a reverse rotation drive in the steering side to make a sharp small turn, and spin spin mode is switched appropriately according to the field conditions. Things and the like are already well known.

However, when the turning mode is switched to the spin turning mode position, and when the traveling is changed from forward to reverse, it is more likely that the spin turning will be performed in reverse when compared with the forward movement. In addition to the sense of discomfort, there is a limit to the backward attention,
Aside from the expert, sudden spin turns are usually very dangerous.

Therefore, according to the present invention, when the traveling mode is changed from forward to reverse, the brake mode is automatically switched to the brake mode when the mode is the spin mode, and the automatic mode is prohibited if necessary.

[0005]

According to a first aspect of the present invention, there is provided a brake turning mode A in which a steering brake 2 is applied to a steering side crawler 1 for turning, and a steering side crawler 1. Slow rotation mode B in which the vehicle is rotated at a slower speed than the outer crawler 1
And a work vehicle capable of turning to a spin turning mode C in which the steering side crawler 1 is driven to rotate in the reverse direction with respect to the outer crawler 1 to turn, the reverse state is detected during the work in the spin turning mode C. The steering turning control device is provided with an automatic switching means 4 for switching to the brake turning mode A by the detection by the means 3.

Further, the invention of claim 2 is a steering turning control device comprising a manual operation switching prohibiting means 5 for prohibiting automatic switching of the turning mode by the automatic switching means 4.

[0007]

According to the first aspect of the present invention, the traveling is changed from the forward traveling to the reverse traveling in the state where the turning mode for steering turning is switched to the spin turning mode C during the work by the worker. Is detected by the reverse drive detection means 3 by a detection switch or the like provided in the main transmission portion, the turning mode is automatically changed to the brake turning mode A by the automatic switching means 4 incorporated in the controller or the like.
Switch to.

As described above, when the running mode is switched to the spin-turning mode C, when the traveling is changed from forward to reverse, the spin-turning in reverse is more uncomfortable with the movement of the aircraft than in forward. In addition to that,
Since there is a limit to the rearward attention, the turning mode is automatically changed to the brake turning mode A immediately by the automatic switching means 4.
By switching to, it is possible to perform a safe steering turn without requiring advanced operation technology.

According to the second aspect of the present invention, in the state where the turning mode is switched to the spin turning mode C, when the reverse detection means 3 detects that the traveling has changed from forward to reverse, normally, the automatic switching is performed. Although the means 4 automatically switches to the brake turning mode A, the spin turning mode C is continued as it is by prohibiting this automatic switching by the switching prohibiting means 5 such as a manually operated changeover switch.

As described above, by prohibiting the automatic switching of the turning mode from the spin turning mode C to the brake turning mode A when the vehicle is moving backward by means of the manual operation switching prohibiting means 5, a person skilled in the operation technique can use it. By doing so, it becomes possible to continue the steering turning in the spin turning mode C even when the vehicle is in reverse, so that the working efficiency can be improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention in a combine as a work vehicle will be described below with reference to the drawings. A traveling device 7 having a pair of left and right crawlers 1 for traveling on the soil surface is disposed below the undercarriage 6 of the combine, and threshed grain culm supplied to the undercarriage 6 by being sandwiched by a feed chain 8. Then, a threshing apparatus 10 having a grain tank 9 for selectively collecting the threshed grains and temporarily storing the threshed grains is mounted. This threshing device 10
Body 11 for cultivating a napped culm from the front end position on the front side of the
And a raising section 12 that causes a weeded culm, a cutting blade section 13 that cuts off the raised culm, and a culm that conveys the cut culm to the rear and delivers it to the feed chain 8. The harvesting device 15 having the transport unit 14 is attached to the chassis 6.
The reaping suspension section 16 suspends and supports the front end portion of the above so as to be vertically rotatable, and is provided so as to be vertically movable with respect to the soil surface. An operating device 17 for controlling the operation of the combine and an operating seat 18 for this operation are provided on one side of the reaping device 15,
An engine 19 is mounted below the operator's seat 18, the grain tank 9 is arranged on the rear side thereof, and the combine device is provided by the traveling device 7, the threshing device 10, the cutting device 15, the operating device 17, the engine 19 and the like. The vehicle body 20 of FIG.

A traveling mission case 21 is mounted on the front end side of the chassis 6, and a gear transmission mechanism is internally provided in the mission case 21. This gear transmission mechanism is
As shown in FIGS. 3 and 4, a shift gear groove 23a into which a shift shifter 25 that is slidable left and right by a shifter stay 24 is fitted is provided in a double shift gear 23 that rotates about an input shaft 22 as a first shaft. By the action of the shift shifter 25, the shift gear 23 and the counter shaft 26 as the second shaft
A high-speed gear 27 and a low-speed gear 28, which are axially locked to each other, are interlocked and interlocked with each other, and a transmission gear 29 is horizontally and axially fixed to the counter shaft 26, and a steering shaft 30 as a third shaft.
The two steering center gears 31 that are axially locked to each other are meshed and interlocked with each other in order to transmit the shift power between the high speed side and the low speed side by the counter shaft 26.

Clutch claws 31b for meshing are provided on both side surfaces of the steering center gear 31, respectively. Clutch claws 32b meshingly connected to the clutch claws 31b on the side surface of the gear portion 32a are provided close to the left and right clutch claws 31b. The left and right steering clutches 32 each having a left and right steering shafts 32 are respectively supported by the steering shafts 30, and the left and right steering clutches 32 are respectively provided on the opposite extension parts of the clutch pawls 32b. 2 is engaged and provided, and the return spring 50 of the steering clutch 32 is internally provided in this extension portion.
A shifter groove 32c into which the left and right steering shifters 33 for sliding the steering clutch 32 to the left and right are respectively inserted is provided between the 2a and the extended portion.
3a of the clutch claws 31b and 3b
The steering clutch 32 is disengaged, and the steering clutch 32 is disengaged, and the steering brake 2 is braked at the same time by disengaging the clutch claws 31b and 32b from the side where the steering clutch 32 is engaged. It is configured to act on the side.

A small-diameter gear 31a of one of the two steering center gears 31, a gentle revolving gear 35 rotatably mounted on a revolving shaft 34 as a sixth shaft, and a free revolving shaft 36 on a reduction shaft 36 as a fourth shaft. The two small intermediate gears 37a of the two spin intermediate gears 37 are engaged with each other and linked, and the other large diameter gear 37b of the intermediate spin gear 37 and the rotating shaft 34
The spin swivel gear 38, which is supported on the free swivel shaft, is meshed and interlocked, and between the slow swivel gear 35 and the spin swivel gear 38,
A switching clutch 39 having clutch pawls 39a on both sides is arranged, and a switching shifter 40 for sliding the clutch 39 left and right is fitted into the switching clutch 39.
b is provided, and by the action of the switching shifter 40, one of the clutch claws 39a and one of the clutch claws 35a and 38a provided on each side surface of the two swivel gears 35 and 38 is provided.
It is configured to be engaged and connected separately.

Each gear portion 3 of the left and right steering clutches 32
2a and two left and right steering power transmission gears 41 which are idled by the reduction shaft 36 are meshed with each other, and left and right swivel transmission gears 42 are idled by the swivel shaft 34, respectively. The left and right turning clutches 43 for axially rotating the transmission gear 42 are axially stopped, and the left and right turning transmission gears 42 are rotated.
And the left and right two turning intermediate gears 45, which are idler bearings on the turning intermediate shaft 44 as the seventh shaft, are engaged with each other, and one small diameter gear 45 of the left and right turning intermediate gears 45 is engaged.
a and the left and right steering transmission gears 41 are in mesh with each other.

One small diameter gear 41a of the two left and right steering transmission gears 41 and the left and right wheel shafts 46 as a fifth shaft.
The left and right wheel gears 47 fixed to one end of the left and right wheels mesh with each other in interlock with each other, and the left and right driving wheels 48 for driving the left and right crawlers 1 are respectively fixed to the other ends of the left and right wheel shafts 46. Configure. A swing mode switching lever 51 that operates a switching clutch 39 that switches the swing modes of the brake swing mode A, the slow swing mode B, and the spin swing mode C, and as shown in FIG. A valve changeover switch 52 is provided which is engaged and turned on at the position of the turning mode C. As shown in FIG. 6, the main gear shift lever 53 for switching the vehicle body 20 between forward and backward and for shifting the vehicle speed, and the protrusion 53a of the lever 53 turning plate when the main gear shift lever 53 is switched to the reverse position. The reverse detection means 3 is provided by a detection switch or the like which is turned on in combination.

As shown in FIG. 7, a power steering lever 54 for steering the vehicle body 20 to the left and right and turning, and a connecting rod 54a connected to the lower portion of the power steering lever 54 are operated by tilting the lever 54 left and right. A rotary plate 56 that rotates left and right around the fulcrum shaft 55 by swinging up and down is provided, and the action of a detection plate 56a arranged in an L shape of the rotary plate 56 causes the variable throttle valve of the hydraulic power steering circuit to be described later. 57
A variable switch 58 for controlling the turning and a turning execution switch 59 for executing a slow turning or a spin turning are provided so as to be able to be turned on and off, and the timing of turning on this is set to the variable switch 5
8 is configured to act faster than the turning execution switch 59, and a position sensor 60 such as a potentiometer for detecting the left or right tilt position of the power steering lever 54 is engaged with the lever 54. 61 is a return spring. The turning mode switching lever 51, the main transmission lever 53 and the power steering lever 54 are connected to the operating device 1
It is arranged on one side of the upper part of 7.

As shown in FIG. 8, the mission case 2
1. The shifter shaft 33 of the steering shifter 33 that causes the left and right steering clutches 32 to project outward from the front wall 21a of No. 1
The left and right clutch arms 62 that are axially fixed to a are attached to the front wall 2
The left and right clutch sensors 6 are rotated by the operation of the left and right steering cylinders 63 arranged in 1a and detect this rotation.
4 is provided.

The CPU 65 is mainly used to control the operation of each automatic circuit, and at the time of reverse travel, the controller 65 having the automatic switching means 4 for automatically switching the turning mode from the spin turning mode C to the brake turning mode A is operated. It is provided in the vicinity of the device 17, and as shown in FIG. 9, on the input side of this controller 65, a valve changeover switch 52, a variable switch 58, a turning execution switch 59, a position sensor 60,
The left and right clutch sensors 64, the reverse detection means 3, the switching prohibiting means 5 and the like, which are arranged in the vicinity of the main speed change lever 53 and are manually operated to prohibit the automatic switching of the turning mode, are connected, and their outputs are connected. To the side, a steering clutch solenoid valve 66 for operating the steering cylinder 63 of the left and right steering clutches 32, a swing clutch solenoid valve 67 for operating the left and right swing clutches 43, and the left and right steering clutches 32.
The pressure relief solenoid valves 68 and the like for suppressing the braking pressure of the steering brake 2 associated with the turning off are connected and configured.

The steering hydraulic circuit S for driving the turning in the brake turning mode A and the turning hydraulic circuit T for driving the turning in the slow turning mode B or the spin turning mode C have different circuit configurations, and the steering is performed. As shown in FIG. 10, the hydraulic circuit S supplies the pressure oil supplied from the hydraulic pump 70 from the same oil tank 69 that operates the hydraulic continuously variable transmission H, the harvesting device 15 and other hydraulic systems to the steering clutch. Via the solenoid valve 66, one side of the left and right steering cylinders 63 that actuate the left and right steering clutches 32 and the steering brake 2 is switchably connected so as to be able to send or return oil, and the left and right steerings are operated. Connection is made to return oil from the other side of the cylinder 63 to the oil tank 69 via the pressure relief solenoid valve 68 and the variable throttle valve 57 or the fixed throttle 71.

The swing hydraulic circuit T is, as shown in FIG.
The left or right swing clutch 43 is actuated by the pressure oil supplied from the transmission case 21 by the hydraulic pump 72, and the swing clutch solenoid valve 67 switches and connects oil feed or oil return. The gear transmission in the traveling transmission case 21 is based on the input shaft 2.
When the power is transmitted to the low-speed gear 28, the dual transmission gears 23 of the input shaft 22 are slid left and right, and when the high-speed gear 27 is rotated by the countershaft 26, the high-speed gear 27 is interlocked with the low-speed gear 28. At this time, the transmission is shifted to a low speed, and the shifted power is transmitted to the countershaft 26 similarly to the transmission gear 2 which rotates.
9, the steering center gear 3 that rotates about the steering shaft 30
Link to 1.

At the time of this interlocking, the turning mode switching lever 51
Is switched to the brake turning mode A, the valve selector switch 52 is turned off and the pressure relief solenoid valve 68 is connected to the power steering circuit side. In this state, for example, the power steering lever 54 is tilted to the left. At this time, the tilt position is detected by the position sensor 60, and the variable throttle valve 57 of the power steering circuit is actuated by turning on the variable switch 58 engaged with the connecting rod 54a connected to the lever 54, and the steering clutch solenoid valve. By switching 66 to the left, the left steering cylinder 63 causes the left steering shifter 33 to act, and this action causes the steering center gear 3 to move.
The clutch pawl 31b of No. 1 and the clutch pawl 32b of the left steering clutch 32 are disengaged to allow the steering clutch 32 rotating about the steering shaft 30 to idle, and at the same time,
Braking with the left steering brake 2.

By this braking, the rotation of the two left steering transmission gears 41 idled on the reduction shaft 36 interlocking with the gear portion 32a of the steering clutch 32 is stopped and the steering center gear 31 is rotated. To the right steering transmission gear 41 from the steering clutch 32 on the right side, and further, from one small diameter gear 41a of the steering transmission gear 41 to the right driving wheel 48 via the right wheel gear 47. Interlock. The driving of the right crawler 1 by the right driving wheel 48 and the braking of the left steering clutch 32 cause the left crawler 1 in the braking state to make a left turn. .

Next, when the speed change transmission gear 29 is linked to the steering center gear 31, the swing mode switching lever 51 is switched to the gentle swing mode B so that one of the small diameter gears 31a of the steering center gear 31 is linked. Swivel axis 34
The clutch claw 35a of the loosely swiveling gear 35 that freely rotates and the clutch claw 39a of the switching clutch 39 that axially rotates are meshed and connected by the switching shifter 40 to axially rotate the slow swiveling gear 35, and the switching lever 51 When the power switch lever 54 is tilted to the left in the ON state of the valve changeover switch 52 associated with the switching operation, this tilted position is detected by the position sensor 60 and is engaged with the connecting rod 54a connected to the lever 54. Adjustable switch 58
The operation of the variable throttle valve 57 of the power steering circuit by turning on
By switching the steering clutch solenoid valve 66 to the left, the left steering cylinder 63 causes the left steering shifter 33 to act, and this action causes the clutch pawl 31b of the steering center gear 31 and the left steering clutch 32 to operate. The clutch claw 32b of 1 is disengaged, and the steering clutch 32 that is rotating about the steering shaft 30 is idled.

When the idling of the steering clutch 32 is detected by the clutch sensor 64, the pressure relief solenoid valve 68 is switched to the bypass circuit side, and the fixed throttle 71 of the bypass circuit acts to operate the steering clutch 32. The turning clutch 2 is held in the off state and the steering brake 2 is not braked. Further, when the turning execution switch 59 that engages with the connecting rod 54a connected to the lever 54 is turned on, the turning clutch electromagnetic valve 67 causes the left turning clutch 43 to rotate. , The left swivel transmission gear 42, which rotates about its axis, is rotated from the slow swivel gear 35, and the swivel intermediate shaft 4 is rotated from this swivel transmission gear 42.
4 is interlocked with the left two turning intermediate gears 45, which rotate freely, to the left two steering power transmitting gears 41, which rotate freely by the disengagement of the steering clutch 32. 41 via the small-diameter gear 41a, the left wheel gear 47, and the left drive wheel 48 to drive the left crawler 1 and the right crawler 1.
A slow turn to the left is performed by decelerating the vehicle.

Next, when the speed change transmission gear 29 is interlocked with the steering center gear 31, the turning mode switching lever 51 is switched to the spin turning mode C, so that one of the small diameter gears 31a of the steering center gear 31 moves from the reduction shaft. 36 is interlocked with the small diameter gear 37a of the two spin intermediate gears 37 which are idled to 36, and is inverted from the large diameter gear 37b to be interlocked with the spin orbiting gear 38 which is idled to the orbiting shaft 34. By this inversion, The switching claw 38a of the spin slewing gear 38 that rotates in the reverse direction with respect to the gentle rotation gear 35 and the clutch claw 39a of the switching clutch 39 that rotates axially are connected to each other.
With the meshing connection of 0, the spin turning gear 38 is rotated axially, and, for example, the power steering lever 54 is tilted to the left while the valve changeover switch 52 is in the ON state in accordance with the changeover operation of the changeover lever 51.

With respect to the operation after the operation of the power steering lever 54, the operation stroke equivalent to that of the above-described gentle turning causes
The clutch pawl 31b of the steering center gear 31 and the clutch pawl 32b of the left steering clutch 32 are disengaged, so that the steering clutch 32 rotating about the steering shaft 30 is idly rotated. Is detected by the clutch sensor 64, the steering throttle 32 is kept disengaged by the action of the fixed throttle 71 of the bypass circuit, and the turning execution switch 59 is turned on so that the steering brake 2 is not braked. , The left swing clutch 43 is turned on by the swing clutch solenoid valve 67, and the spin swing gear 38
The left turning transmission gear 42, which idles from the shaft, is axially rotated to drive the left drive wheel 48 to move the left crawler 1 to the right crawler.
The spin rotation to the left is performed by driving the la 1 in the reverse rotation.

As described above, when the turning mode is switched to the spin turning mode C by the turning mode switching lever 51, as shown in the flowchart of FIG. 12, first, the power steering lever 54 is tilted to the left or right. , The steering cylinder 63 is activated to disengage the steering clutch 32, and in the next stage, the turning execution switch 59 is turned on.
If it is NO, the swing mode is not the spin swing mode C. Therefore, the pressure release solenoid valve 68 is switched to the power steering circuit side, and at the same time, the swing clutch solenoid valve 67 is turned off and the brake swing is performed. Let it be done. When the turning execution switch 59 is ON, YES in the next step, the vehicle body 2 is operated by operating the main shift lever 53.
It is checked whether or not the reverse drive state of 0 is detected by the reverse drive detecting means 3. If NO, the pressure release solenoid valve 68 is switched to the bypass circuit side to suppress the braking force, and at the same time the swing clutch solenoid valve 67 is turned on. And make a spin turn. When the reverse state detection by the reverse state detection means 3 is YES, the place where the spin turn should normally be performed is braked by the automatic switching means 4 built in the controller 65 without operating the switching lever 51. The mode is changed to the turning mode A and the brake turning is performed.

By automatically switching the turning mode, it is possible to avoid a spin turn at the time of backward movement, which requires more attention toward the rear, in addition to a feeling of strangeness with respect to the movement of the vehicle body 20 compared to the case of forward movement. Therefore, it is possible to prevent a dangerous state resulting from this and perform a safe steering turn without requiring a high-level operation technique. When the vehicle is in reverse, the turning mode is switched from the spin turning mode C to the brake turning mode A by the automatic switching means 4 as described above. By turning it ON by operation and prohibiting it, it becomes possible for a person skilled in the operation technique to continue the steering turning in the spin turning mode C even when going backward by his own will, thus improving work efficiency. Can be achieved.

Further, as an embodiment different from the above, when tilting the power steering lever 54 to the left or right, according to the detection value of the position sensor 60 for detecting this operation angle,
From the neutral position in the vertical state, the operating angle is divided and set to the shallow operating angle position L, the intermediate operating angle position M, and the deep operating angle position N to the left and right sides, respectively. Turn off, brake turning at intermediate operating angle position M,
At a deep operating angle position N, the steering turning control device is configured to make a slow turn or a spin turn.

During the combine operation, when the turning mode switching lever 51 appropriately switches the respective turning modes to carry out the steering turning, as shown in FIG. 13, the tilt operation angle of the power steering lever 54 is detected by the position sensor 60. In the brake turning mode A, the lever 5
At a shallow operating angle position L of 4, the steering clutch 32 is disengaged, and at an intermediate operating angle position M, brake turning is performed to brake the brake to the lock position. Slow turning mode B
At the shallow operating angle position L of the lever 54, the steering clutch 32 is disengaged, at the intermediate operating angle position M, the brake turning is performed to brake the brake to the lock position, and at the deep operating angle position N, the brake braking is performed. At the lock position, the pressure relief solenoid valve 68 is switched to make a gentle turn. In the spin turning mode C, the steering clutch 32 is disengaged at the shallow operating angle position L of the lever 54, the brake turning is performed to brake the brake to the lock position at the intermediate operating angle position M, and the deep operating angle position N is set. Then, the pressure relief solenoid valve 68 is switched at the lock position of the brake braking to cause the spin turning.

The relationship between the tilt operation angle of the power steering lever 54 and the turning radius of the vehicle body 20 in each of these turning modes is as shown in FIG. Once the turning radius becomes smaller, a turning with a constant radius is performed, and in spin turning,
The turning is performed such that the radius becomes smaller according to the operation angle of the lever 54.

As described above, when the slow turning mode B or the spin turning mode C is switched, the brake turning region by the brake braking, that is, the range between the intermediate operating angle position M and the deep operating angle position N is set to be wide. Brake turning can be performed by the same brake braking as in the turning mode A, the operation such as direction correction is facilitated, and the steering clutch 32 is clearly turned on / off in either the slow turning or the spin turning. The steering clutch 32 does not slip when turning, and wear resistance can be improved.

From the brake turning region to the slow turning or spin turning region, that is, from the intermediate operating angle position M to the deep operating angle position N.
Since the switching position to the same is the same, the operator can easily recognize the switching position between the gentle turning and the spin turning, and the trouble due to an error can be avoided, and the brake turning area after the slow turning or the spin turning is completed. That is, since the steering clutch 32 can be connected at the same level as in the case of the brake turning mode A through the intermediate operation angle position M, connection noise and shock of the steering clutch 32 portion can be reduced. It should be noted that the vehicle body 20 does not move straight ahead at the same time as the end of the slow turn or the spin turn, and the brake braking according to the operation angle of the power steering lever 54 becomes possible, so that the operability such as the direction correction is improved.

Further, the inclination angle to the ground at the rear end portion of the crawler 1 of the traveling device 7 is controlled by moving the crawlers 1 on the left and right with respect to the chassis 6 up and down to control the vehicle body 20 in a front-back or left-right horizontal posture. When the vehicle body is horizontally controlled, the ground surface of the rear wheel 73 side of the crawler 1 is tilted to the ground while the grounding surface of the crawler 1 is pushed down to lift the chassis 6 and the rear portion thereof is further pushed up against the crawler 1. Angle α to front drive wheel 48
The traveling device is configured to have a smaller inclination angle β to the ground.

As shown in FIG. 15, support frames 74a are provided at the lower front ends of the left and right vertical frames 74 fixed in the vertical direction on the left and right sides of the chassis 6 in plan view, and the left and right support frames 7 are provided.
The front ends of the left and right pitching frames 75 located below the left and right vertical frames 74 are rotatably supported by the support shafts 75a on the 4a. A pitching shaft 77 is rotatably supported by a pitching metal 76 fixed to the rear lower sides of the left and right vertical frames 74, respectively.
One end of each of the left and right pitching arms 78a is axially fixed, and the other end of each arm 78a is rotatably pin-connected to the rear end of each of the left and right pitching frames 75. On the pitching shaft 77, a single pinching arm 78b formed in an L shape with respect to the pitching arm 78a.
One end of the cylinder is axially locked, and the other end is connected to the piston 79a of the hydraulically operated pitching cylinder 79, and the cylinder 79 is pin-connected to one side of the vertical frame 74 to form a pinching mechanism.

The left and right rolling frames 8 are arranged substantially in parallel with each other below the outer sides of the left and right pitching frames 75.
Although 0 is arranged, the rolling mechanism for actuating the frame 80 has the same shape on the left and right sides, and only one side will be described. A rolling metal 81 fixed to the front side and lower side of the rear side of the pitching frame 75 has a V-shaped rolling arm front 82a and a rolling arm rear 82b.
Each of the intermediate portions of the rolling frame 80 is supported, and one end of each is rotatably pin-connected to the front and rear adaptive positions of the rolling frame 80. 82b behind the rolling arm
The other end of the rolling arm 83 is connected to the piston 83a of the rolling cylinder 83, and the cylinder 83 is pin-connected to the upper surface of the pitching frame 75, and the position near the connecting portion of the rolling arm rear 82b with the piston 83a. To the other end of the rolling arm front 82a.
4 are connected by pins so as to form a four-point parallel link.

At the rear end of the rolling frame 80, a rear wheel 73 supported by a supporting arm 85 so as to be freely rotatable, and a lower end of the outer surface of the rolling frame 80 is supported at a predetermined interval so as to be freely rotatable. The plurality of grounding wheels 86 that have been grounded and the driving wheels 48 that transmit power from the traveling mission case 21 are wound around the crawlers 1 and stretched, and the supporting arms 85 slide back and forth. Adjusts the tension of the crawler 1, whose orbit changes with the vertical movement of the rolling frame 80.

When the vehicle body 20 sinks from the soil surface due to the sufficient storage of the grains in the grain tank 9 on the soft soil surface, the pitching frame 75 is fully filled with respect to the chassis 6 by the pitching mechanism. When the rolling frame 80 is fully pushed down with respect to the pitching frame 75 by the rolling mechanism, the winding shape of the crawler 1 is formed by the rear roller 73 and the rear ground roller 86a in a side view. The ground inclination angle α of the chrome roller 1 formed is the same as that of the chrome wheel 1 formed by the drive wheel 48 and the front ground roller wheel 86b.
The rear wheel 73 to be smaller than the ground inclination angle β of
By arranging the rear wheel contact roller 86a and the rear grounding wheel 86a, it is possible to improve the escapeability during reverse travel.

[Brief description of drawings]

FIG. 1 is a side view showing the entire combine.

FIG. 2 is a front sectional development view showing a gear transmission mechanism of the traveling transmission case.

FIG. 3 is a front array diagram showing a gear transmission mechanism of a traveling transmission case.

FIG. 4 is a side array diagram showing a gear transmission mechanism of the traveling transmission case.

FIG. 5 is a side view showing an operating state of a turning mode switching lever.

FIG. 6 is a side view showing an arrangement state of the reverse detection unit.

FIG. 7 is a schematic front view showing the operating state of the power steering lever.

FIG. 8 is a partial front view showing an operating state of a clutch sensor.

FIG. 9 is a block diagram showing an electric circuit for automatic control.

FIG. 10 is a block diagram showing a hydraulic circuit for operating a brake turning mode.

FIG. 11 is a block diagram showing a hydraulic circuit for operating a gentle turning mode and a spin turning mode.

FIG. 12 is a flowchart showing a procedure for automatically changing the turning mode when the vehicle is moving backward.

FIG. 13 is an operation comparison view showing an operating state of the power steering lever in each turning mode.

FIG. 14 is a diagram showing a relationship between an operation angle of a power steering lever and a turning radius in each turning mode.

FIG. 15 is a partial side view showing the inclination angles to the ground of the front end portion and the rear end portion of the chlora.

[Explanation of symbols]

 1. Crawler 2. Steering brake 3. Reverse detection means 4. Automatic switching means 5. Switching prohibition means

Claims (2)

[Claims] 1. A brake swivel mode A in which a steering brake 2 is applied to a steering side crawler 1 to turn, and a steering side crawler 1 is driven with a deceleration drive as compared with an outer crawler 1. In the working vehicle capable of switching between the gentle turning mode B for turning and the spin turning mode C for turning by turning the steering side crawler 1 in reverse rotation with respect to the outer crawler 1, during work in the spin turning mode C The reverse state indicates the reverse detection means 3
A steering turning control device provided with an automatic switching means 4 for switching to a brake turning mode A by detection by. 2. The steering turning control device according to claim 1, further comprising a manual operation switching prohibiting means 5 for prohibiting automatic switching of the turning mode by the automatic switching means 4.