Work vehicle

Abstract

To solve the problem in which: a vehicle body is demanded to move as desired even when travelling wheels may spin free.SOLUTION: A work vehicle is equipped with: a plurality of travelling driving devices that drive a plurality of travelling devices 2 respectively; supporting mechanisms A supports the plurality of travelling devices 2 on the vehicle main body 1 to enable them to respectively move up and down; and idling detecting means that detects whether the travelling devices 2 are in an idling state or not. A control device that controls actuation of the travelling driving device and the supporting mechanisms A, when it is detected that the travelling devices 2 are in an idling state, in a state where the plurality of travelling devices 2 are driven at a set rotation speed so that the vehicle body is moving and travelling, executes idling avoidance control by which actuation of the travelling driving devices is controlled so that a driving speed of the travelling devices 2 is equal to a rotation speed which is lower than the set rotation speed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a work vehicle suitable for traveling on uneven ground including uneven surfaces. [Background technology]

[0002] Conventionally, a work vehicle such as the one described above has had four running wheels supported on the vehicle body via a bending link mechanism, and by changing the height of the running wheels relative to the vehicle body, the running wheels can rotate and follow the ground contact, allowing the vehicle body to maintain its posture while running, even if the ground is uneven (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-111985 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described conventional configuration, when the vehicle body moves, the running wheels acting as the running gear are driven to rotate to travel. For example, if the running gear gets into mud, or if the vehicle is traveling on a sandy or slippery road surface with thick vegetation, there is a risk that the running gear will spin freely relative to the road surface, preventing the transmission of driving force and preventing reliable travel.

[0005] Therefore, there has been a demand for a system that allows the vehicle body to move smoothly even when there is a risk of the traveling device spinning freely. [Means for solving the problem]

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[0018] The present invention The features of the work vehicle are as follows: a vehicle body; a plurality of travel devices located at the front and rear on both the left and right sides of the vehicle body; a plurality of travel drive devices for separately driving each of the plurality of travel devices; a support mechanism for supporting the plurality of travel devices on the vehicle body so that each of the plurality of travel devices can be raised and lowered; a control device for controlling the operation of the travel drive devices and the support mechanism; and a spin state detection means for detecting whether or not the travel devices are in a spin state. When the spin state detection means detects that the travel devices are in a spin state while the plurality of travel devices are driven at a set rotation speed and the vehicle body is moving and traveling, the control device controls the drive speed of the travel device that has been detected to be in a spin state to be equal to or lower than the set rotation speed. It is preferable that the control means is configured to execute spin avoidance control for controlling the operation of the traveling drive device so that the rotation speed is lower than the rotation speed of the traveling drive device, and that when, after executing the spin avoidance control, the spin state detection means detects that the traveling device is in a spinning state, vehicle body movement control is executed to control the operation of the support mechanism so as to move the vehicle body by sequentially performing, with the vehicle body movement stopped, a front wheel movement process for moving the traveling device on the front side in the direction of travel forward in the direction of travel relative to the vehicle body, a body movement process for moving the vehicle body forward in the direction of travel, and a rear wheel movement process for moving the traveling device on the rear side in the direction of travel forward in the direction of travel relative to the vehicle body.

[0019] According to this configuration, even if the control device executes the wheel spin avoidance control, when the wheel spin detection means detects that the traveling device is in a wheel spin state, the vehicle body movement control is executed. When executing the vehicle body movement control, first, the traveling device on the front side in the traveling direction is moved to the front side in the traveling direction with respect to the vehicle body. At this time, the traveling device on the front side in the traveling direction may be rotationally driven, may be freely rotated, or may be in a state of being stopped from rotating. Next, the vehicle body is moved to the front side in the traveling direction. Due to the movement of the vehicle body, the center of gravity position of the vehicle body is in a state where more load is supported by the traveling device on the lower side in the traveling direction. Then, the traveling device on the rear side in the traveling direction is moved to the front side in the traveling direction with respect to the vehicle body. At this time, since the load burden on the traveling device on the rear side in the traveling direction is small, the vehicle body can pull only the traveling device on the rear side in the traveling direction to the front side in the traveling direction while remaining moved to the front side in the traveling direction.

[0020] As a result, by executing the vehicle body movement control, even when the traveling device rotates idly and the vehicle body cannot be moved, the vehicle body can be surely moved.

[0021] In the present invention, it is preferable that prior to the control device executing the front wheel movement process, the center of gravity position of the vehicle body is shifted to the rear side in the traveling direction and the traveling device on the rear side in the traveling direction is driven to stop.

[0022] According to this configuration, since the center of gravity position of the vehicle body is shifted to the rear side in the traveling direction, the load burden on the traveling device on the front side in the traveling direction is in a state of being small, and moreover, since the traveling device on the rear side in the traveling direction is stopped, it is easy to smoothly perform the front wheel movement process.

[0023] In the present invention, it is preferable that the control device controls the operation of the traveling drive device so as to rotationally drive the traveling device on the front side in the traveling direction in the front wheel movement process.

[0024] According to this configuration, since the front wheel movement process is executed while rotationally driving the traveling device on the front side in the traveling direction, the movement of the traveling device on the front side in the traveling direction is smoothly performed.

[0025] In the present invention, it is preferable that the control device controls the operation of the traveling drive device so as to rotationally drive the traveling device on the rear side in the traveling direction in the rear wheel movement process.

[0026] According to this configuration, since the rear wheel movement process is executed while rotationally driving the traveling device on the rear side in the traveling direction, the movement of the traveling device on the rear side in the traveling direction is smoothly performed.

Brief Description of the Drawings

[0027] [Figure 1] It is a side view of the work vehicle. [Diagram 2] It is a plan view of the work vehicle. [Diagram 3] It is a control block diagram. [Figure 4] It is a flowchart showing the control operation. [Diagram 5] It is a flowchart showing the control operation. [Figure 6] It is a diagram showing the reference posture. [Figure 7] It is an operation explanatory diagram. [Figure 8] It is an operation explanatory diagram. [Figure 9] It is an operation explanatory diagram. [Figure 10] It is an operation explanatory diagram.

Modes for Carrying Out the Invention

[0028] Embodiments of the present invention will be described based on the drawings. In the following description, the direction of the arrow FW shown in the figure is defined as "front", the direction of the arrow BK as "rear", the direction of the arrow RH as "right", the direction of the arrow LH as "left", the direction of the arrow UP as "up", and the direction of the arrow DW as "down".

[0029] As shown in Figures 1 and 2, the work vehicle is equipped with a vehicle body 1 which is approximately rectangular in plan view and supports the entire vehicle, a number of running wheels 2 which serve as running devices supporting the vehicle body 1, a number of auxiliary wheels 3 provided corresponding to each of the multiple running wheels 2, a support mechanism A which supports the multiple running wheels 2 so that their position can be changed relative to the vehicle body 1, and a number of hydraulic motors 4 which serve as running drive devices which drive each of the multiple running wheels 2.

[0030] The traveling wheels 2 are located at the front and rear on both the left and right sides of the vehicle body 1. In this embodiment, the work vehicle is equipped with four traveling wheels 2, located at the left front, right front, left rear, and right rear. It also has four support mechanisms A, located at the left front, right front, left rear, and right rear. The support mechanisms A include a bending link mechanism 5 and a plurality of hydraulic cylinders 6, 7 that can individually change the position of the bending link mechanism 5.

[0031] A flat loading section 8 capable of loading luggage is provided on the upper portion of the vehicle body 1. For example, luggage such as containers for storing harvested products can be loaded and supported on the loading section 8.

[0032] The vehicle body 1 is provided below the loading section 8 with a hydraulic supply source 9 that sends hydraulic oil toward the hydraulic cylinders 6, 7 and the hydraulic motor 4, a valve mechanism 10 that adjusts the supply state of hydraulic oil from the hydraulic supply source 9, and an ECU (Electronic Control Unit) 11 that controls the operation of the valve mechanism 10. The hydraulic supply source 9 has a hydraulic pump driven by the engine. The ECU 11 has a microcomputer and is capable of executing various controls according to a control program. The valve mechanism 10 has a plurality of hydraulic control valves 13 that supply and discharge hydraulic oil or adjust the flow rate. The hydraulic control valves 13 and the ECU 11 constitute a control device C.

[0033] [Support mechanism] As described above, the support mechanism A includes the bending link mechanism 5 and the plurality of hydraulic cylinders 6, 7. The four traveling wheels 2 are supported by the bending link mechanism 5 so as to be able to rise and fall individually with respect to the vehicle body 1.

[0034] The bending link mechanism 5 includes a base end 14 supported by the vehicle body 1, a first link 15 having an upper end supported on the lower part of the base end 14 so as to be rotatable about a horizontal axis X1, and a second link 16 having one end supported on the lower end of the first link 15 so as to be rotatable about a horizontal axis X2 and having the running wheel 2 supported at the other end.

[0035] 2, a support bracket 17 that supports the traveling wheel 2 is supported by a boss portion 18 provided at the swing side end of the second link 16 so as to be swingable around a vertical axis Y. A hydraulic cylinder 20 for a swing operation (hereinafter referred to as a swing cylinder) is provided between a bracket 19 on one end side of the second link 16 and an arm portion 17a provided on the support bracket 17.

[0036] A plurality of hydraulic cylinders 6, 7 capable of individually changing the posture of each of the bending link mechanisms 5 are provided corresponding to the plurality of bending link mechanisms 5. That is, a first hydraulic cylinder 6 capable of changing the swing posture of the first link 15 relative to the vehicle body 1, and a second hydraulic cylinder 7 capable of changing the swing posture of the second link 16 relative to the first link 15 are provided.

[0037] When the first hydraulic cylinder 6 is extended or retracted with the second hydraulic cylinder 7 stopped, the first link 15, the second link 16, and the traveling wheel 2 swing together around the horizontal axis X1 of the pivot connection point with respect to the base end 14 while maintaining a constant relative posture. When the second hydraulic cylinder 7 is extended or retracted with the first hydraulic cylinder 6 stopped, the second link 16 and the traveling wheel 2 swing together around the horizontal axis X2 of the connection point between the first link 15 and the second link 16 while maintaining a constant posture of the first link 15.

[0038] Auxiliary wheels 3 are rotatably supported at intermediate bent portions of each of the multiple bent link mechanisms 5. The auxiliary wheels 3 are configured with wheels having approximately the same outer diameter as the running wheels 2. A support shaft that pivotally connects the first link 15 and the second link 16 is extended so as to protrude outward in the vehicle body width direction, and the auxiliary wheels 3 are rotatably supported at the extended protruding portion of the support shaft.

[0039] By operating the turning cylinder 20, the traveling wheel 2 can be turned around the vertical axis Y relative to the articulating link mechanism 5, thereby enabling the vehicle to be turned.

[0040] The flow rate of the hydraulic oil is adjusted by the hydraulic control valve 13 corresponding to the hydraulic motor 4, so that the rotation speed of the hydraulic motor 4, that is, the rotation speed of the traveling wheels 2, can be changed.

[0041] [Sensor] This work vehicle is equipped with various sensors. 3, each of the four second hydraulic cylinders 7 is provided with a head side pressure sensor S1 and a cap side pressure sensor S2. The head side pressure sensor S1 detects the hydraulic pressure in the head side chamber of the second hydraulic cylinder 7. The cap side pressure sensor S2 detects the hydraulic pressure in the cap side chamber of the second hydraulic cylinder 7. These pressure sensors S1, S2 correspond to pressure detection means that individually detect the pressure when the traveling wheels 2 contact the ground surface.

[0042] 3, a plurality of stroke sensors S3 capable of detecting the amount of extension / retraction operation are provided for each of the four first hydraulic cylinders 6 and the four second hydraulic cylinders 7. The amount of extension / retraction operation of each hydraulic cylinder 6, 7 is a detection value corresponding to the swing position of the first link 15 and the second link 16 that are the objects of operation.

[0043] The vehicle body 1 is provided with an inclination sensor S4 for detecting the inclination state of the vehicle body. The inclination sensor S4 is an inertial measurement unit (IMSU) having a well-known configuration. The IMU has a three-axis acceleration sensor and a gyro sensor, and can detect changes in the attitude of the vehicle body 1, specifically, tilt in the front-rear and left-right directions.

[0044] A rotation sensor S5 is provided near the traveling wheels 2 to detect the rotation speed of the traveling wheels 2 driven by the hydraulic motor 4. Also, a pressure sensor S6 is provided to detect the pressure of hydraulic oil supplied to the hydraulic motor 4. Each of the four rotating cylinders 20 is provided with a stroke sensor S7 capable of detecting the amount of extension / retraction operation.

[0045] [ECU] The ECU 11 includes a posture control unit 100, a driving control unit 101, and a discrimination unit 102 as discrimination means. When the vehicle travels with the four traveling wheels 2 on the ground, the driving control unit 101 controls the amount of hydraulic oil supplied to the hydraulic motor 4 for each of the four traveling wheels 2 based on the rotation speed of the traveling wheels 2 detected by the rotation sensor S5 so that the rotation speed of the traveling wheels 2 becomes a target value, and also controls the pressure of the hydraulic oil supplied to the hydraulic motor 4 based on detection information from the pressure sensor S6 so that the drive torque of the traveling wheels 2 becomes a target value.

[0046] When the vehicle body is moving, the posture control unit 100 controls the operation of the support mechanism A so that the vehicle body 1 is in a horizontal posture based on the detection information of the inclination sensor S4. In this control, the posture control unit 100 controls the operation of the four first hydraulic cylinders 6 and the four second hydraulic cylinders 7 so that the inclination angles in the front-rear direction and the left-right direction from the horizontal posture of the vehicle body 1 become values ​​corresponding to the horizontal posture based on the detection information of the inclination sensor S4.

[0047] The attitude control unit 100 further controls the operation of the support mechanism A so that the pressure detected by the pressure sensors S1, S2 becomes the set pressure while the vehicle body is moving and traveling. By executing such pressure control, for example, if there is a depression in the ground and one of the traveling wheels 2 is raised above the ground, the ground contact pressure decreases, so the traveling wheel 2 is lowered so that the pressure becomes the set pressure. As a result, each of the multiple traveling wheels 2 can maintain an appropriate ground contact state and support the vehicle body 1 while smoothly traveling on uneven ground.

[0048] Furthermore, even if the running wheels 2 are not raised, for example, if the running wheels 2 get into mud, or when the vehicle is traveling on a sandy or slippery road surface due to overgrown vegetation, even if the running wheels 2 are driven to rotate by the operation of the hydraulic motor 4, they may spin freely and the vehicle may not be able to move smoothly.

[0049] The discrimination unit 102 is configured to discriminate that the traveling wheels 2 are in a spinning state when the internal pressure of the hydraulic oil supply passage in the hydraulic motor 4 falls below a preset value based on the detection information of the pressure sensor S6.

[0050] Therefore, the pressure sensor S6 and the determination unit 102 constitute a free-spinning state detection means Q that detects whether or not the traveling device is in a free-spinning state.

[0051] When the vehicle body is moving and traveling with the four traveling wheels 2 driven at a set rotational speed, and the travel control unit 101 detects that the traveling wheels 2 are in a spinning state by the spinning state detection means Q, the travel control unit 101 executes spin avoidance control to control the operation of the hydraulic motor 4 so that the drive speed of the traveling wheels 2 detected to be in a spinning state becomes a rotational speed slower than the set rotational speed.

[0052] The traveling control unit 101 is further configured to execute vehicle body movement control that enables the vehicle body to move without relying on the rotation of the running wheels 2 when the spin state detection means Q detects that the running wheels 2 are in a spinning state after executing the spin avoidance control.

[0053] The control executed by the ECU 11 will be described with reference to the flowcharts of FIG. 4 and FIG.

[0054] As shown in Fig. 4, while the vehicle body is moving and traveling, posture control is executed to control the operation of the four support mechanisms A (step #01). That is, based on the detection information of the inclination sensor S4, the operation of the four first hydraulic cylinders 6 and the four second hydraulic cylinders 7 is controlled so that the inclination angle in the front-rear direction and the inclination angle in the left-right direction from the horizontal posture of the vehicle body 1 become values ​​corresponding to the horizontal posture. Also, the operation of the support mechanisms A, specifically, the four first hydraulic cylinders 6 and the four second hydraulic cylinders 7 is controlled so that the pressure detected by the pressure sensors S1 and S2 (corresponding to the ground pressure of the traveling wheels 2) becomes a set pressure. By performing control in this manner, the posture of the vehicle body is maintained in a horizontal posture while the traveling wheels 2 are made to follow the ground contact along the unevenness of the traveling road surface.

[0055] Simultaneously with the posture control, the operation of the hydraulic motor 4 is controlled (Step #02). That is, for each of the four traveling wheels 2, the operation of the hydraulic motor 4 is controlled so that the rotation speed of the traveling wheel 2 detected by the rotation sensor S5 becomes a preset target speed (corresponding to a set rotation speed) and the drive torque detected by the pressure sensor S6 becomes a target value.

[0056] Next, while the work vehicle is moving, it is determined whether any of the four traveling wheels 2 is in an idling state where the traveling wheel 2 is spinning freely (step #3). Specifically, even if the rotation speed detected by the rotation sensor S5 is the target rotation speed or a speed close to it, it is determined whether the detection value of the pressure sensor S6 corresponding to the drive torque at that time has fallen below a lower limit value that is set by a set amount lower than the target value, and if the detection value has fallen below the lower limit value, it is determined that the traveling wheel 2 is in an idling state (YES branch of step #03).

[0057] If it is determined that the traveling wheels 2 are spinning freely, the rotation speed of the traveling wheels 2 is decelerated to a low rotation speed of approximately half the set rotation speed (Step #04). If this decelerated state continues for a set time (several seconds) (Step #05), the counter is counted up and the determination process of Step #03 is executed (Steps #06, #07). If the spinning state is resolved, the process returns to Step #01 and posture control and operation control of the hydraulic motor 4 are executed.

[0058] If the spin state is not resolved even after the deceleration process for decelerating the rotation speed of the traveling wheels 2 is executed, the deceleration process is executed repeatedly, and when the count value N of the number of repetitions reaches the set number Ns, the vehicle body movement control is executed next (step #08). Since the spin state cannot be resolved even after the spin avoidance control for decelerating the drive speed of the traveling wheels 2 is executed, the vehicle body movement control described below is executed.

[0059] The vehicle body movement control will be described with reference to FIG. When the control is started, the posture of the support mechanism A is changed to the reference posture shown in Fig. 6 (step #11). That is, compared to the normal traveling mode shown in Fig. 1, the first link 25 is swung inward so that the front and rear traveling wheels 2 approach each other in the front-rear direction.

[0060] Then, a posture changing operation is performed by the support mechanism A (articulated link mechanism 5) so that the center of gravity G of the body moves from the above-mentioned reference posture to the rear side of the body (step #12).

[0061] The actual center of gravity position G can also be calculated based on information on the inclination angle from the horizontal position of the vehicle body 1 detected by the inclination sensor S4 and the state of the support mechanism A detected by the stroke sensor S3 (the inclination angle of the first link 25 and the inclination angle of the second link 26, etc.). However, instead of calculating the actual center of gravity position G, the center of gravity is moved so as to be closer to the rear of the center of the distance (wheelbase) between the running wheel 2 located at the front of the traveling direction (hereinafter referred to as the front running wheel) and the running wheel 2 located at the rear of the traveling direction (hereinafter referred to as the rear running wheel).

[0062] Next, as shown in Fig. 7, the front running wheel 2 is moved forward in the traveling direction relative to the vehicle body 1 (step #13). For example, while the second link 26 supporting the front running wheel 2 is kept in a horizontal position, the first link 25 is swung forward to move the front running wheel 2 forward. This process corresponds to the front wheel movement process.

[0063] When the front wheel movement process is executed, the front running wheels 2 are driven to rotate in the traveling direction while following the ground contact, while the rear running wheels 2 are stopped from rotating.

[0064] In this way, the center of gravity G of the vehicle body is shifted rearward, the load is increased on the rear running wheels, and the front running wheels 2 are moved while the rear running wheels 2 are stopped from rotating, so that the front running wheels 2 can move easily.

[0065] Next, as shown in Fig. 8, with both the front and rear running wheels 2 stopped from rotating, the vehicle body 1 is moved forward in the traveling direction (step #14). This process corresponds to the body movement process. This process causes the center of gravity G of the vehicle body to move forward.

[0066] Furthermore, thereafter, as shown in Fig. 9, the rear running wheels 2 are moved forward in the traveling direction relative to the vehicle body 1 (step #15). This process corresponds to the rear wheel movement process. When this rear wheel movement process is executed, the rear running wheels 2 are driven to rotate in the traveling direction while following the ground. On the other hand, the front running wheels 2 are stopped rotating.

[0067] After the rear wheel movement process is executed, the vehicle assumes the same posture as the reference posture shown in FIG. 6 (see FIG. 10), but the vehicle body is moved a predetermined amount in the forward direction.

[0068] In this way, the vehicle center of gravity position G is shifted forward, the load on the front running wheels is increased, and the rear running wheels 2 are moved while the front running wheels 2 are stopped from rotating, so that the rear running wheels 2 can move easily.

[0069] [Another embodiment] (1) In the above embodiment, the control device C (ECU 11) controls the operation of the support mechanism A so that the pressure detected by the pressure sensor S6 becomes the set pressure when the vehicle body is moving. However, such pressure control may not be executed.

[0070] (2) In the above embodiment, the idling state detection means Q is constituted by the pressure sensor S6 and the discriminator 102. However, instead of this configuration, the following configuration may be used. The idling state detection means Q may be constituted by a rotation sensor S5 which detects the driving speed of the hydraulic motor 4, a running speed detection means which detects the actual running speed of the vehicle body 1, and a discrimination means which discriminates that the running wheels 2 are in an idling state when the driving speed of the hydraulic motor 4 detected by the rotation sensor S5 becomes faster than the actual running speed detected by the running speed detection means by a set amount or more.

[0071] To explain further, the traveling speed detection means may be, for example, a means for calculating the average value of the drive speeds of four hydraulic motors 4 provided corresponding to the four traveling wheels 2, and calculating the traveling speed from this average value. Instead of this configuration, a measuring device may be used that can calculate the absolute traveling speed of the work vehicle relative to the ground surface by using a millimeter wave radar or the like.

[0072] The control device C compares the drive speed of one hydraulic motor 4 to be measured with the actual running speed of the vehicle body 1 measured by the running speed detection means described above, and determines that the running wheels 2 are in a spinning state when the drive speed becomes faster than the actual running speed by a set amount or more.

[0073] (3) In the above embodiment, when it is determined that the running wheel 2 is spinning freely, the rotational speed of the running wheel 2 is decelerated to a low rotational speed of approximately half the set rotational speed. However, the rotational speed to be decelerated is not limited to the above speed, and various configurations can be used, such as a configuration in which the rotational speed is decelerated in stages or a configuration in which the rotational speed is gradually decreased.

[0074] (4) In the above embodiment, the vehicle body movement control is configured to move the center of gravity G of the vehicle body rearward in the direction of travel and stop the driving of the rear running wheels 2 prior to executing the front wheel movement processing. However, instead of this configuration, a configuration may be used in which only the processing of moving the center of gravity G rearward in the direction of travel is executed prior to executing the front wheel movement processing, or only the processing of stopping the driving of the rear running wheels 2 is executed, or none of these processing may be executed.

[0075] (5) In the above embodiment, the front running wheels 2 are rotationally driven in the front wheel movement process. However, they may be in a free rotation state or may be stopped from rotating.

[0076] (6) In the above embodiment, the rear running wheels 2 are rotationally driven in the rear wheel movement process. However, they may be in a free rotation state or may be stopped from rotating.

[0077] (7) In the above embodiment, the vehicle body is configured to be always supported by the running wheels 2 being in contact with the ground. However, for example, it may be configured to include support legs that can be switched between a state of protruding downward from the running wheels 2 and contacting the ground and a state of retracting upward from the contact portion of the running wheels 2. Then, when performing the front wheel movement process and the rear wheel movement process, the support legs may be brought into the grounded state to hold the position of the vehicle body 1.

[0078] (8) In the above embodiment, the support mechanism A is configured to include the bending link mechanism 5 and the plurality of hydraulic cylinders 6 and 7. However, instead of this configuration, the support mechanism A may be a mechanism including one link or three or more links, and as a device for changing the posture of the support mechanism A, it may include an electric actuator.

[0079] (9) In the above embodiment, the hydraulic motor 4 is used as the traveling drive device. However, instead of this configuration, it may be configured to be driven by an electric motor, an engine, or the like.

Industrial Applicability

[0080] The present invention can be applied to a work vehicle suitable for traveling on rough ground where irregularities exist.

Explanation of Reference Numerals

[0081] 1 Vehicle body 2 Running wheels 4 Traveling drive device (hydraulic motor) 5 Bending link mechanism 6,7 Hydraulic cylinders 102 Discrimination unit (discrimination means) A Support mechanism C Control device Q Idling state detection means S1,S2 Pressure detection means (pressure sensor) S6 Pressure sensor

Claims

1. A vehicle body, A plurality of traveling devices respectively positioned at the front and rear on both left and right sides of the vehicle body, A plurality of traveling drive devices that individually drive each of the plurality of traveling devices, A support mechanism that supports the plurality of traveling devices on the vehicle body so that they can be individually lifted and lowered, A control device that controls the operation of the traveling drive device and the support mechanism, A wheel spin state detection means for detecting whether the traveling device is in a wheel spin state, and is provided, The control device, In a state where the plurality of traveling devices are driven at a set rotational speed and the vehicle body is moving forward, when it is detected by the wheel spin state detection means that the traveling device is in a wheel spin state, the control device is configured to execute a wheel spin avoidance control for controlling the operation of the traveling drive device so that the drive speed of the traveling device detected to be in a wheel spin state becomes a rotational speed lower than the set rotational speed, and, After executing the wheel spin avoidance control, when it is detected by the wheel spin state detection means that the traveling device is in a wheel spin state, the control device is configured to execute a vehicle body movement control for controlling the operation of the support mechanism so as to move the vehicle body by sequentially performing a front wheel movement process of moving the traveling device on the front side in the traveling direction forward with respect to the vehicle body, a main body movement process of moving the vehicle body forward in the traveling direction, and a rear wheel movement process of moving the traveling device on the rear side in the traveling direction forward with respect to the vehicle body in a state where the vehicle body movement is stopped.

2. The work vehicle according to claim 1, wherein the control device, prior to executing the front wheel movement process, moves the vehicle body center of gravity position to the rear side in the traveling direction and stops driving the traveling device on the rear side in the traveling direction.

3. The work vehicle according to claim 1 or 2, wherein the control device controls the operation of the traveling drive device so as to rotationally drive the traveling device on the front side in the traveling direction in the front wheel movement process.

4. The work vehicle according to any one of claims 1 to 3, wherein the control device controls the operation of the traveling drive device so as to rotationally drive the traveling device on the rear side in the traveling direction in the rear wheel movement process.

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