Work vehicle

Abstract

To provide a working vehicle capable of performing work on a slope.SOLUTION: A work vehicle includes a vehicle body 11, a travel device 19, a support mechanism 13 that supports the travel device 19 and can change a distance between a ground contact surface of the travel device 19 and the vehicle body 11, a work device 20 that is attached to the vehicle body 11 and performs a predetermined work, and a height adjustment mechanism 26 that adjusts a work height of the work device 20 in accordance with an operation of the support mechanism 13.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a work vehicle. [Background technology]

[0002] Patent Document 1 discloses a spraying device for spraying chemicals in orchards. This spraying device has a lifting frame attached to each of left and right support columns erected on a traveling vehicle body so that it can be raised and lowered, and each lifting frame is equipped with a spray nozzle. This spraying device is used to spray chemicals in a terraced field with sloping land on both sides of a substantially horizontal aisle where fruit trees are planted. The spraying device raises the lifting frame to position the spray nozzle in a high position for fruit trees planted on the upper slope (mountain side) across the aisle, and lowers the lifting frame to position the spray nozzle in a low position for fruit trees planted on the lower slope (valley side) across the aisle, thereby spraying chemicals at an appropriate height for fruit trees on the slope above and below the aisle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 4-50155 Summary of the Invention [Problem to be solved by the invention]

[0004] The spraying device of Patent Document 1 can be suitably used in stepped fields with approximately horizontal paths, but is not intended for use on sloping ground where the entire field, including the paths, is inclined. The present disclosure aims to provide a work vehicle that can perform work on slopes. [Means for solving the problem]

[0005] The work vehicle is The vehicle body, Running gear and a support mechanism that supports the traveling device and is capable of changing the distance between a ground contact surface of the traveling device and the vehicle body; a work device attached to the vehicle body and performing a predetermined task; a height adjustment mechanism for adjusting the working height of the working device, The height adjustment mechanism adjusts the working height of the working device in response to the operation of the support mechanism. [Effects of the Invention]

[0006] According to the work vehicle of the present disclosure, work can be performed on slopes using a work device. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a side view of a work vehicle. [Figure 2] FIG. 2 is a plan view of the work vehicle shown in FIG. [Figure 3] FIG. 3 is an explanatory diagram of the support mechanism at the right front portion. [Figure 4] FIG. 4 is a control block diagram of the work vehicle. [Figure 5] FIG. 5 is a front view illustrating the operation of the support mechanism. [Figure 6] FIG. 6 is a side view illustrating the operation of the support mechanism. [Figure 7] FIG. 7 is a front view and a side view illustrating the operation of the support mechanism of the work vehicle traveling on a slope. [Figure 8] FIG. 8 is a schematic front view showing the working device. [Figure 9] FIG. 9 is a front view illustrating the operation of the support mechanism and the height adjustment mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0008] <Summary of Embodiments of the Present Disclosure> The following provides an outline of embodiments of the present disclosure. (1) The work vehicle of this embodiment includes a vehicle body and Running gear and a support mechanism that supports the traveling device and is capable of changing the distance between a ground contact surface of the traveling device and the vehicle body; a work device attached to the vehicle body and performing a predetermined task; a height adjustment mechanism for adjusting the working height of the working device, The height adjustment mechanism adjusts the working height of the working device in response to the operation of the support mechanism.

[0009] In a work vehicle configured as described above, the support mechanism changes the distance between the ground contact surface of the traveling device and the vehicle body, so that the attitude of the vehicle body, for example, the height and inclination (levelness) of the vehicle body, can be maintained at a predetermined level even if the ground level changes due to changes in the inclination angle of the ground, etc. Furthermore, when the attitude of the vehicle body is controlled in response to changes in the ground level, the height (distance) of the work device attached to the vehicle body from the ground changes, but the height adjustment mechanism can adjust the working height of the work device in response to changes in ground level. Therefore, work can be performed using the work device even on sloping ground where the entire surface is inclined.

[0010] (2) In the work vehicle of (1) above, the height adjustment mechanism adjusts the working height in response to the operation of the support mechanism to change the distance.

[0011] (3) In the work vehicle of (1) or (2) above, the height adjustment mechanism lowers the working height when the support mechanism increases the distance, and raises the working height when the support mechanism decreases the distance.

[0012] When the ground level drops while the work vehicle is traveling, the support mechanism increases the distance between the ground contact surface of the traveling gear and the vehicle body to maintain the posture of the vehicle body. When the ground level drops and the posture of the vehicle body is maintained in this manner, the distance between the work equipment attached to the vehicle body and the ground increases. Therefore, the height adjustment mechanism lowers the working height of the work equipment so that it is closer to the ground. Conversely, if the ground level rises while the work vehicle is traveling, the support mechanism shortens the distance between the ground contact surface of the traveling device and the vehicle body to maintain the posture of the vehicle body. As the ground level rises and the posture of the vehicle body is maintained in this manner, the distance between the work device attached to the vehicle body and the ground decreases. Therefore, the height adjustment mechanism raises the working height of the work device to move it away from the ground. In this way, the working height of the work implement can be adjusted in accordance with changes in the ground level.

[0013] (4) In the work vehicle of (1) above, the traveling device includes a first wheel arranged on one side of the vehicle body in the horizontal direction and a second wheel arranged on the other side, the work device includes a first work device that performs work around the one side of the vehicle body, The height adjustment mechanism adjusts the working height of the first working device in response to the operation of the support mechanism to change a first distance between the ground contact surface of the first wheel and the vehicle body.

[0014] When the ground level differs between one horizontal side (e.g., the left or front side) and the other horizontal side (e.g., the right or rear side) of the vehicle body due to an incline, the posture of the vehicle body can be maintained by changing the distance between the ground contact surfaces of the first and second wheels located on one and the other side of the vehicle body. Also, the working height of the first working device that performs work around one side of the vehicle body can be adjusted in accordance with changes in the ground level on which the first wheel travels.

[0015] (5) In the work vehicle of (4) above, the work device includes a second work device that performs work on the other side of the vehicle body, The height adjustment mechanism adjusts the working height of the second working device in response to the operation of the support mechanism to change the second distance between the ground contact surface of the second wheel and the vehicle body.

[0016] According to the above configuration, the working height of the second working device that performs work around the other side of the vehicle body can be adjusted in accordance with changes in the height of the ground on which the second wheels travel.

[0017] (6) In the work vehicle of (4) above, the height adjustment mechanism lowers the working height of the first work device when the support mechanism lengthens the first distance, and raises the working height of the first work device when the support mechanism shortens the first distance.

[0018] (7) In the work vehicle of (5) above, the height adjustment mechanism lowers the working height of the second work device when the support mechanism increases the second distance, and raises the working height of the second work device when the support mechanism decreases the second distance.

[0019] (8) The work vehicle according to any one of (1) to (7) above further includes a tank attached to the vehicle body for storing a liquid used in the work device.

[0020] According to the above configuration, when the vehicle body is maintained in a horizontal position, by attaching the tank to the vehicle body, the imbalance of the liquid in the tank is suppressed, making it easier to consume the liquid in the tank.

[0021] (9) In the work vehicle of (8) above, a plurality of the tanks are provided, The tanks are arranged on one side and the other side of the vehicle body in the horizontal direction.

[0022] According to the above configuration, it is possible to prevent the weight balance of the vehicle body from being disturbed by attaching the tank, and to achieve stable driving even on slopes.

[0023] <Details of the embodiment of the present invention> DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. At least some of the embodiments described below may be combined in any desired manner.

[0024] [Overall configuration of the work vehicle] Figure 1 is a side view of the work vehicle. Figure 2 is a plan view of the work vehicle shown in Figure 1. The work vehicle 10 shown in Figures 1 and 2 is a vehicle that can travel on uneven road surfaces (uneven ground) and slopes.

[0025] In the following explanation, the direction of the arrow FW shown in the figure is the "front" of the work vehicle 10, which is the straight-ahead direction (direction of travel) of the work vehicle 10. The direction of the arrow BK is the "rear" of the work vehicle 10, which is opposite to the straight-ahead direction. The direction of the arrow RH is the "right" of the work vehicle 10 moving straight, and the direction of the arrow LH is the "left" of the work vehicle 10 moving straight. The direction of the arrow DW is the "bottom" of the work vehicle 10, which is the road surface side, and the direction of the arrow UP is the "top" of the work vehicle 10, which is the side opposite the road surface.

[0026] The work vehicle 10 has a vehicle body 11, traveling gear 19, multiple support mechanisms 13, a control device 17, and a working device 20. The work vehicle 10 of this embodiment has multiple wheels 12 as the traveling gear 19, specifically four wheels 12. The work vehicle 10 has the same number (four) of support mechanisms 13 as the wheels 12. The support mechanisms 13 connect the vehicle body 11 and the wheels 12. The wheels 12 are located at the front and rear of both the left and right sides of the vehicle body 11.

[0027] The vehicle body 11 has a frame 21. The vehicle body 11 has a loading section 22 on top of the frame 21, on which cargo can be loaded. The loading section 22 has a flat loading surface 221 on its upper surface. The loading surface 221 has a substantially rectangular shape in a plan view (see FIG. 2). The loading surface 221 is provided so as to extend in the left-right and front-rear directions. The cargo to be loaded is, for example, agricultural equipment, agricultural materials such as fertilizer and chemicals, harvested crops, harvest baskets, or pallets on which these are placed.

[0028] The support mechanisms 13 are located at the left front, right front, left rear, and right rear of the vehicle body 11. The support mechanisms 13 are attached to the vehicle body 11 (part of the frame 21) and support the wheels 12 so that their positions can be changed relative to the vehicle body 11. In particular, the support mechanisms 13 change the distance between the contact surface (the lower surface that contacts the ground) of the wheels 12 and the vehicle body 11. This distance is, for example, the vertical distance between the lower surface of the wheels 12 and the mounting surface 221 of the vehicle body 11 (for example, distances L, L1 to L6 shown in FIGS. 5 to 7). The support mechanisms 13 have articulation link mechanisms 30 as operating parts operable to change the position of the wheels 12. The wheels 12 are attached to the articulation link mechanisms 30. The support mechanisms 13 have actuators 14 that drive the articulation link mechanisms 30.

[0029] The actuator 14 operates the bending link mechanism 30 to change the posture of the bending link mechanism 30. The actuator 14 is a fluid cylinder, and in this embodiment, has a first hydraulic cylinder 36 and a second hydraulic cylinder 37. The specific configuration of the support mechanism 13 will be described later. The travelling device 19 of the work vehicle 10 has a plurality of hydraulic motors 15. The hydraulic motors 15 are provided at the ends of the articulating linkages 30 together with the wheels 12. The hydraulic motors 15 are travelling actuators that drive the wheels 12 to rotate.

[0030] The wheels 12 are driven wheels that are rotated by hydraulic motors 15. The rotation of the wheels 12 causes the work vehicle 10 to travel. The travel device of the work vehicle 10 has a plurality of auxiliary wheels 16. The auxiliary wheels 16 are attached midway along the articulating link mechanism 30. The auxiliary wheels 16 are attached to the connecting parts (joint parts) between a first link 31 and a second link 32, which will be described later and which make up the articulating link mechanism 30. The auxiliary wheels 16 are driven wheels that can rotate freely.

[0031] The work vehicle 10 has a hydraulic unit (hydraulic pressure supply source) 51, a battery 52, and an engine 53. The hydraulic unit 51 supplies hydraulic oil to the hydraulic motor 15, the first hydraulic cylinder 36, the second hydraulic cylinder 37, and a swing hydraulic cylinder 38 (described later). The hydraulic unit 51 has a hydraulic pump 54 driven by the engine 53, multiple hydraulic control valves 55, and a hydraulic oil tank 56.

[0032] A hydraulic control valve 55 is connected to each of the hydraulic motor 15 and the hydraulic cylinders 36, 37, 38. The hydraulic control valve 55 is an electromagnetic valve and has the function of supplying, stopping the supply of hydraulic oil from the hydraulic pump 54, and adjusting the supply flow rate. The control device 17 adjusts the supply state (supply amount) of hydraulic oil from the hydraulic unit 51 by controlling the hydraulic control valve 55. In other words, the control device 17 controls the operations of the hydraulic motor 15 and the hydraulic cylinders 36, 37, and 38.

[0033] The hydraulic unit 51, the battery 52, the engine 53, and the control device 17 are mounted on the vehicle body 11 (frame 21), and are located below the loading section 22 in this embodiment (see FIG. 1). The battery 52 supplies power to the control device 17, the hydraulic unit 51, and a number of sensors, which will be described later. The work vehicle 10 has an operating handle 18 that is gripped by an operator. The operating handle 18 is attached to a frame 21.

[0034] [Support mechanism 13] The support mechanism 13 supports the wheels 12 so that they can be raised and lowered individually relative to the vehicle body 11. To this end, the support mechanism 13 has a bending link mechanism 30. Figure 3 is an explanatory diagram of the right front support mechanism 13fR. The bending link mechanism 30 has a first link 31 and a second link 32. Each of the first link 31 and the second link 32 is a linear member.

[0035] A fixing bracket 23 is fixed to a part of a frame 21 of the vehicle body 11 . A first end 311 of the first link 31 on the frame 21 side is supported by the fixed bracket 23 so as to be swingable about a first horizontal axis X1 in the left-right direction. A first end 321 of the second link 32 is supported by a second end 312 of the first link 31 so as to be swingable about a second horizontal axis X2 in the left-right direction. A support bracket 33 is attached to the second end 322, which is the tip side of the second link 32. The wheel 12 is supported by the support bracket 33.

[0036] A set of actuators 14 is provided for one articulating link mechanism 30 having a first link 31 and a second link 32. The set of actuators 14 includes one first hydraulic cylinder 36 and one second hydraulic cylinder 37. The first hydraulic cylinder 36 extends and retracts to swing the first link 31 around the first horizontal axis X1. The first hydraulic cylinder 36 changes the swing posture of the first link 31 relative to the vehicle body 11. The second hydraulic cylinder 37 extends and retracts to swing the second link 32 around the second horizontal axis X2. The second hydraulic cylinder 37 changes the swing posture of the second link 32 relative to the first link 31.

[0037] The hydraulic control valve 55 connected to the first hydraulic cylinder 36 and the hydraulic control valve 55 connected to the second hydraulic cylinder 37 are separate valves (see Figure 4), and the first hydraulic cylinder 36 and the second hydraulic cylinder 37 operate to extend and retract independently. Figure 4 is a control block diagram of the work vehicle 10. The extension and retraction operations of the first hydraulic cylinder 36 and the second hydraulic cylinder 37 cause the articulating link mechanism 30 to bend and extend.

[0038] In Figure 3, for example, when the first hydraulic cylinder 36 extends and retracts while the second hydraulic cylinder 37 is stopped, the first link 31, the second link 32, and the wheel 12 swing together around the first horizontal axis X1 while maintaining a constant relative positional relationship. When the second hydraulic cylinder 37 extends and retracts while the first hydraulic cylinder 36 is stopped, the second link 32 and the wheel 12 swing together around the second horizontal axis X2 while the posture of the first link 31 relative to the vehicle body 11 is maintained constant.

[0039] A support bracket 33 that supports the wheel 12 is attached to the second link 32. The hydraulic motor 15 is mounted on the support bracket 33. The support bracket 33 is attached to a second end 322 of the second link 32 so as to be swingable around a vertical axis Y in the up-down direction. The support mechanism 13 of the work vehicle 10 has a hydraulic cylinder 38 for swinging (hereinafter referred to as the swing cylinder 38) for changing the rolling direction of the wheels 12. The swing cylinder 38 is attached between a part of the second link 32 and the support bracket 33. When the swing cylinder 38 extends and retracts, the support bracket 33 and the wheels 12 swing around the vertical axis Y. The traveling direction of the work vehicle 10 is changed by the operation of the swing cylinder 38.

[0040] As described above, the work vehicle 10 of this embodiment has four support mechanisms 13, and each support mechanism 13 is provided with a set of actuators 14. The set of actuators 14 provided on one support mechanism 13 and the other set of actuators 14 provided on another support mechanism 13 are separate actuators, and each actuator 14 operates independently. This allows the four wheels 12 to move individually relative to the vehicle body 11. Furthermore, it is possible to vary the positions of the four wheels 12 relative to the vehicle body 11. The support mechanisms 13 make it possible to change the distance, particularly the vertical distance, between the contact surface of each wheel 12 and the vehicle body 11.

[0041] [Sensor] Figure 4 is a control block diagram of the work vehicle. Figure 4 mainly shows the configuration related to the left front support mechanism 13. Although detailed configurations of the other support mechanisms 13 are omitted in Figure 4, they have the same configuration as the left front support mechanism 13.

[0042] The work vehicle 10 has multiple sensors S1 to S8. A head side pressure sensor S1 and a rod side pressure sensor S2 are connected to the second hydraulic cylinder 37. The head side pressure sensor S1 detects the internal pressure of the head side oil chamber of the second hydraulic cylinder 37. The rod side pressure sensor S2 detects the internal pressure of the rod side oil chamber of the second hydraulic cylinder 37. The control device 17 acquires the detection signals of the sensors S1 and S2.

[0043] A stroke sensor S3 that detects the amount of extension / contraction is provided to each of the first hydraulic cylinder 36 and the second hydraulic cylinder 37. The amount of extension / contraction of each of the first hydraulic cylinder 36 and the second hydraulic cylinder 37 is related to the swing position of each of the first link 31 and the second link 32. Therefore, the detection value of the stroke sensor S3 is correlated with the swing position of each of the first link 31 and the second link 32. The detection value of the stroke sensor S3 uniquely determines the position of the wheel 12 relative to the vehicle body 11. The control device 17 can acquire the detection signal of the stroke sensor S3 and detect the position of the wheel 12.

[0044] As described above, the work vehicle 10 has a head-side pressure sensor S1, a rod-side pressure sensor S2, and a stroke sensor S3 as detection devices for detecting the movement of the support mechanism 13 (articulated link mechanism 30). The operation of the actuator 14, which has the first hydraulic cylinder 36 and the second hydraulic cylinder 37, is detected by the stroke sensor S3 (detection device). The control device 17 can obtain the movement of the support mechanism 13 based on the detection signal of the stroke sensor S3.

[0045] The vehicle body 11 is provided with an inclination sensor S4 that detects the inclination state of the vehicle body 11. The inclination sensor S4 is configured using an inertial measurement unit (IMU), which is a well-known configuration. The IMU of this embodiment has a triaxial acceleration sensor and a gyro sensor. The IMU of this embodiment detects changes in the attitude of the vehicle body 11, specifically, tilt in the front-rear and left-right directions. The control device 17 acquires a detection signal from the inclination sensor S4.

[0046] A rotation sensor S5 that detects the rotation speed of the wheel 12 is provided near the wheel 12. The control device 17 acquires a detection signal from the rotation sensor S5. Based on the detection value of the rotation sensor S5, the supply of hydraulic oil to the hydraulic motor 15 is controlled so that the rotation speed of the wheel 12 becomes a target value.

[0047] The work vehicle 10 has a pressure sensor S6 that detects the pressure of the hydraulic oil supplied to the hydraulic motor 15. The control device 17 acquires the detection signal of the pressure sensor S6. Based on the pressure of the hydraulic oil detected by the pressure sensor S6, the supply (pressure) of the hydraulic oil to the hydraulic motor 15 is controlled so that the drive torque of the wheels 12 becomes a target value. A stroke sensor S7 capable of detecting the amount of extension and contraction is provided on each of the four swing cylinders 38. The control device 17 acquires the detection signal of the stroke sensor S7. In response to this, the traveling direction of the vehicle 10 is controlled.

[0048] [Control device 17] The control device 17 has an ECU 171 (Electronic Control Unit) that functions as a main control unit that controls the operation of the vehicle 10. The ECU 171 has a microcomputer and executes various controls according to a control program. The ECU 171 has a non-volatile memory that stores programs corresponding to the functional units that execute the various controls, and a CPU that executes the programs. The functions (controls) of the functional units are realized by the CPU executing the programs.

[0049] The ECU 171 has an attitude control unit 172 as one of the functional units. The attitude control unit 172 executes horizontal control and center of gravity position control. The control device 17 (ECU 171) controls the actuators 14 and performs attitude control to maintain the vehicle body 11 in a predetermined attitude while traveling. In the following description, the "predetermined posture" is a posture in which the loading section 22 (loading surface 221) of the vehicle body 11 is horizontal (horizontal posture), but it may be a posture other than the horizontal posture.

[0050] (Horizontal Control) The posture control unit 172 (ECU 171) performs horizontal control based on the detection signal from the inclination sensor S4 when the work vehicle 10 is traveling. The horizontal control is a control that operates the front, rear, left, and right support mechanisms 13 so that the loading unit 22 (placing surface 221) is in a horizontal position. Based on the detection signal from the inclination sensor S4, the posture control unit 172 (ECU 171) determines the tilt angles in the front-rear direction and the left-right direction, with the vehicle main body 11 (loading unit 22) in a reference position in which the vehicle main body 11 is in a horizontal position. The posture control unit 172 (ECU 171) controls the operation of the four first hydraulic cylinders 36 and the four second hydraulic cylinders 37 so that these tilt angles become values ​​corresponding to the horizontal position (i.e., the tilt angles are zero).

[0051] The horizontal control will be further explained. The ECU 171 calculates the target operation amounts of the four first hydraulic cylinders 36 and the four second hydraulic cylinders 37 required to make the loading unit 22 horizontal, based on the tilt attitude (tilt angle) of the loading unit 22 detected by the tilt sensor S4. The ECU 171 controls the operation of the four first hydraulic cylinders 36 and the four second hydraulic cylinders 37 so that the actual operation amounts detected by the stroke sensor S3 become the target operation amounts.

[0052] (Center of gravity control) The posture control unit 172 (ECU 171) determines the center of gravity position of the vehicle body 11 based on the detection information of the inclination sensor S4 and the stroke sensor S3, and can perform center of gravity position control to control the operation of the front, rear, left and right support mechanisms 13 so that the center of gravity position is located in the center of multiple (four) wheels 12 in a planar view.

[0053] The center of gravity position control will be further explained below. The tilt state of the vehicle body 11 is detected by the output of the tilt sensor S4. The posture control unit 172 (ECU 171) obtains the tilt angle in the front-to-rear direction and the tilt angle in the left-to-right direction from the horizontal posture of the vehicle body 11 based on the detection signal of the tilt sensor S4. The state of the support mechanism 13 (the angle of the first link 31 relative to the vehicle body 11, and the angle of the second link 32 relative to the first link 31) is detected based on the detection results of the extension / contraction amounts of the first hydraulic cylinder 36 and the second hydraulic cylinder 37 detected by the multiple stroke sensors S3.

[0054] As a result, it is possible to obtain by calculation what posture (inclination state) the vehicle body 11 is in as a whole and what position the center of gravity of the vehicle body 11 is in relative to the ground contact positions of the four wheels 12. The posture control unit 172 (ECU 171) operates the first hydraulic cylinder 36 and the second hydraulic cylinder 37 so that the center of gravity position thus determined becomes the target posture in which the center of multiple (four) wheels 12 is located in the center in a planar view.

[0055] In this way, center of gravity position control is a control that adjusts the pressure (force) supporting the vehicle body 11 so that the center of gravity of the vehicle body 11 converges to the target center of gravity regardless of the unevenness or inclination of the road surface. As a variation of the center of gravity position control, the attitude control unit 172 (ECU 171) does not determine the center of gravity position of the vehicle body 11, but determines the ground contact pressure of multiple (four) wheels 12. The ground contact pressure is determined based on detection signals from pressure sensors S1 and S2. In this case, the attitude control unit 172 (ECU 171) controls the operation of the support mechanism 13 so that the ground contact pressure of the wheel 12 located on the lower side and the ground contact pressure of the wheel 12 located on the upper side are equal to each other.

[0056] By controlling the center of gravity position, it becomes possible to generate driving force on all the wheels 12 in accordance with the uneven shape of the road surface. By performing horizontal control and center of gravity position control, the ECU 171 can operate the support mechanism 13 so that the placing surface 221 is in a horizontal position and so that all wheels 12 generate driving force in accordance with the uneven shape of the road surface.

[0057] The attitude control unit 172 (ECU 171) performs attitude control (center of gravity position control) of the work vehicle 10, and when the support mechanism 13 operates, all of the plurality (four) of wheels 12 come into contact with the road surface and the vehicle travels (see FIGS. 5 and 6). That is, when the bending link mechanism 30 operates by the actuator 14, all of the plurality (four) of wheels 12 come into contact with the road surface and the vehicle travels.

[0058] FIG. 5 is a front view for explaining the operation of the support mechanism. FIG. 6 is a side view for explaining the operation of the support mechanism. FIGS. 5(a) and 6(a) show a state in which the four wheels 12 are in contact with a road surface at a constant height. The distance between the ground contact surface of the wheel 12 and the vehicle body 11 (the height of the mounting surface 221) at this time is denoted by the symbol L. When any one of the wheels 12 passes through the concave portion Q1 of the road surface as shown in FIGS. 5(b) and 6(b) from this state, the support mechanism 13 (bending link mechanism 30) operates so as to increase the distance between the ground contact surface of the wheel 12 and the vehicle body 11 (from the distance L to the distance L1 (where L1 > L)) by the attitude control of the attitude control unit 172 (ECU 171). In other words, the support mechanism 13 (bending link mechanism 30) operates so that the wheel 12 descends with respect to the vehicle body 11. The descent here includes not only straight down but also diagonal downward descent.

[0059] Conversely, when any one of the wheels 12 passes through the convex portion Q2 of the road surface as shown in FIGS. 5(c) and 6(c), the support mechanism 13 (bending link mechanism 30) operates so as to shorten the distance between the ground contact surface of the wheel 12 and the vehicle body 11 (from the distance L to the distance L2 (where L2 < L)) by the attitude control of the attitude control unit 172 (ECU 171). In other words, the support mechanism 13 (bending link mechanism 30) operates so that the wheel 12 ascends with respect to the vehicle body 11. The ascent here includes not only straight up but also diagonal upward ascent.

[0060] By the above operations, the work vehicle 10 can be made to travel while the mounting surface 221 of the vehicle body 11 is maintained horizontally and the height of the mounting surface 221 is maintained constant.

[0061] FIG. 7 is a front view and a side view for explaining the operation of the support mechanism of the work vehicle traveling on a slope. When the work vehicle 10 travels across a slope, as shown in FIG. 7(a), the support mechanism 13 operates so as to shorten the distance between the ground contact surface of one of the left and right wheels 12 located on the upper side of the slope (the right side in the figure) and the vehicle body 11. Specifically, the support mechanism 13 operates so as to change the distance L shown in FIG. 5(a) to the distance L3 shown in FIG. 7(a) (where L3 < L). The support mechanism 13 operates so as to increase the distance between the ground contact surface of the other of the left and right wheels 12 located on the lower side of the slope (the left side in the figure) and the vehicle body 11. Specifically, the support mechanism 13 operates so as to change the distance L shown in FIG. 5(a) to the distance L4 shown in FIG. 7(a) (where L4 > L and L4 > L3).

[0062] When the work vehicle 10 climbs or descends a slope, as shown in FIG. 7(b), the support mechanism 13 operates so as to shorten the distance between the ground contact surface of one of the front and rear wheels 12 located on the upper side of the slope (the right side in the figure) and the vehicle body 11. Specifically, the support mechanism 13 operates so as to change the distance L shown in FIG. 6(a) to the distance L5 shown in FIG. 7(b) (where L5 < L). Further, the support mechanism 13 operates so as to increase the distance between the ground contact surface of the other of the left and right wheels 12 located on the lower side of the slope and the vehicle body 11. Specifically, the support mechanism 13 operates so as to change the distance L shown in FIG. 6(a) to the distance L6 shown in FIG. 7(b) (where L6 > L and L6 > L5).

[0063] By each of the above operations, the mounting surface 221 of the vehicle body 11 can be maintained horizontally, and the work vehicle 10 can be made to travel while the height of the mounting surface 221 is maintained constant.

[0064] [Working device 20] As shown in FIGS. 1 and 2, the working device 20 of the work vehicle 10 is a device for performing a predetermined work on the periphery of the work vehicle 10. The working device 20 of the present embodiment is a spraying device. The spraying device 20 sprays a liquid such as water, fertilizer, and agricultural chemicals onto plants PL1, PL2 such as trees and grass, for example, as shown in FIG. 9. The spraying device 20 of the present embodiment sprays a liquid onto a tree planted on the ground and having a certain height.

[0065] The work vehicle 10 of this embodiment is equipped with multiple (two) spray devices 20. The two spray devices 20 are provided on both left and right sides in the front of the vehicle body 11. Therefore, the left spray device 20 is disposed near the left front wheel 12fL and support mechanism 13fL, and the right spray device 20 is disposed near the right front wheel 12fR and support mechanism 13fR.

[0066] The working device 20 is not limited to a spraying device. For example, the working device 20 may be a sensor that detects diseases of the plants PL1 and PL2, or a harvesting arm that harvests fruits of the plants PL1 and PL2.

[0067] FIG. 8 is a schematic front view showing the working device. As also shown in FIGS. 1, 2, and 8, the spray device 20 includes a spray unit 24, a supply unit 25, and a height adjustment mechanism . The spray unit 24 is attached to the vehicle body 11. As shown in Fig. 2, the spray unit 24 of this embodiment is attached to the front of the vehicle body 11 at the ends in the left and right directions.

[0068] Spray unit 24 has a linear conduit 241 and a plurality of nozzles 242 spaced apart along the longitudinal direction of conduit 241. Conduit 241 is arranged with its longitudinal direction facing up and down. Liquid supplied from supply unit 25 flows inside conduit 241. The plurality of nozzles 242 are spray ports that spray the liquid flowing through conduit 241 to the outside. The plurality of nozzles 242 spray the liquid in the same direction.

[0069] 2 and 8, the nozzle 242 sprays liquid outward in the left-right direction from the vehicle body 11. Specifically, the nozzle 242 of the spray unit 24 of the spray device 20 arranged on the left side of the vehicle body 11 sprays liquid to the left, and the nozzle 242 of the spray unit 24 of the spray device 20 arranged on the right side of the vehicle body 11 sprays liquid to the right. This spray direction of the nozzle 242 is an example and can be changed as appropriate.

[0070] 8, spray unit 24 is supported by vehicle body 11 so as to be movable in the vertical direction. For example, conduit 241 of spray unit 24 is supported by guide member 27 attached to vehicle body 11 so as to be movable in the vertical direction. Guide member 27 can be formed by, for example, a guide rail or a guide roller.

[0071] The supply unit 25 supplies the liquid to the spray unit 24. The supply unit 25 includes a tank 251, a pump 252, and a supply pipe 253. Tank 251 stores the liquid to be sprayed from spray unit 24. As shown in Figures 1 and 2, tank 251 is attached to vehicle body 11. Vehicle body 11 has a mounting frame 60 for mounting tank 251.

[0072] The work vehicle 10 of this embodiment is equipped with multiple tanks 251, specifically two tanks 251. Each tank 251 may be provided for each of the two spray devices 20, or may be shared by the two spray devices 20. In the former case, the spraying unit 24 of one spray device 20 sprays the liquid in one tank 251, and the spraying unit 24 of the other spray device 20 sprays the liquid in the other tank 251. In the latter case, the spraying units 24 of both spray devices 20 spray the liquid in both tanks 251.

[0073] The tanks 251 are formed in a rectangular parallelepiped shape. The length of the tanks 251 in the left-right direction is shorter than the length in the front-rear direction. The two tanks 251 are arranged on the left and right sides of the vehicle body 11. Therefore, the tanks 251 are attached to the vehicle body 11 with their longitudinal directions facing the front-rear direction.

[0074] The mounting frame 60 has a mounting portion 601, a connecting portion 602, and a support portion 603. The mounting portion 601 is a portion of the mounting frame 60 that is directly attached to the tank 251 and is attached to the tank 251 so as to surround the outer circumferential surface at the front and rear ends of the tank 251. The connecting portion 602 is a linear member extending in the front-rear direction and connects the front and rear mounting portions 601 on each side in the left-right direction. The support portion 603 is a linear member extending in the left-right direction and connects the left and right mounting portions 601 arranged on the front side to each other and the left and right mounting portions 601 arranged on the rear side to each other, respectively. The mounting frame 60 is attached so as to straddle the mounting surface 221 in the left-right direction by placing the support portion 603 on the mounting surface 221. Using such a mounting frame 60, two tanks 251 can be easily arranged on both the left and right sides of the vehicle main body 11.

[0075] As described above, by distributing the multiple tanks 251 to both the left and right sides of the vehicle body 11, it is possible to prevent imbalance in the weight balance between the left and right sides of the vehicle body 11. This is particularly effective when the work vehicle 10 travels on slopes. Furthermore, by attaching the tank 251 to the vehicle body 11, which is level-controlled (attitude-controlled), the attitude of the tank 251 is also controlled, and it is possible to prevent uneven distribution of liquid in the tank 251. This makes it easier to consume all of the liquid in the tank 251 without leaving any behind. Note that the two tanks 251 may be distributed to both the front and rear sides of the vehicle body 11.

[0076] 8, supply pipe 253 connects tank 251 and spray unit 24. Pump 252 is provided in supply pipe 253 and sucks liquid from tank 251 and supplies it to spray unit 24. Pump 252 is driven by the power of engine 53. Pump 252 is attached to vehicle body 11. For example, pump 252 is attached to frame 21 below loading section 22 of vehicle body 11.

[0077] The height adjustment mechanism 26 adjusts the height of the spray unit 24. The height adjustment mechanism 26 includes, for example, a hydraulic cylinder 261. The hydraulic cylinder 261 is attached between the vehicle body 11 and the spray unit 24. The hydraulic cylinder 261 moves up and down. The operation of the hydraulic cylinder 261 raises and lowers the spray unit 24. Note that the height adjustment mechanism 26 is not limited to a hydraulic cylinder, and may be other actuators such as a pneumatic cylinder or an electric cylinder. The height adjustment mechanism 26 may also be a winding transmission mechanism including a chain or belt that is moved up and down by the power of an electric motor, a hydraulic motor, or the like. The height adjustment mechanism 26 may not include an actuator, and may instead manually adjust the height of the spray unit 24.

[0078] 4, a hydraulic control valve 57 is connected to the hydraulic cylinder 261. The hydraulic control valve 57 is an electromagnetic valve, and has the function of supplying, stopping the supply of, and adjusting the supply flow rate of hydraulic oil from the hydraulic pump 54. The control device 17 controls the hydraulic control valve 57 to adjust the supply state (supply amount) of hydraulic oil from the hydraulic unit 51. In other words, the control device 17 controls the operation of the hydraulic cylinder 261.

[0079] The hydraulic cylinder 261 is provided with a stroke sensor S8 that detects the amount of extension / retraction. The amount of extension / retraction of the hydraulic cylinder 261 is related to the height of the sprayer unit 24 relative to the ground. This height is also referred to as the "spray height (working height)" of the spraying device (working device) 20. Therefore, the spray height of the sprayer unit 24 can be detected based on the detection value of the stroke sensor S8. The control device 17 acquires the detection signal of the stroke sensor S8. Therefore, the control device 17 can acquire the movement of the height adjustment mechanism 26 based on the detection signal of the stroke sensor S8. Note that the spray height refers to the height H from the ground of the range (working range) W over which the sprayer unit 24 sprays liquid, as shown in FIG. 8 . The spray range (working range) W refers to, for example, the distance from the uppermost nozzle 242 to the lowermost nozzle 242 of the sprayer unit 24. The spray height refers to, for example, the height H of the lowermost nozzle 242 from the ground. In addition, in this embodiment, the height of the vehicle body 11 from the ground (the distance L between the contact surface of the wheel 12 and the vehicle body 11 (support surface 221) (see also Figures 5 and 6)) is controlled to be constant, so the spray height may be the height of the spray range W of the spray section 24 from the vehicle body 11 (support surface 221).

[0080] The ECU 171 of the control device 17 has, as a functional unit, a "height control unit 173" that controls the spray height of the spray device 20. The height control unit 173 (ECU 171) controls the spray height of the spray device 20 in association with the attitude control (horizontal control) of the vehicle body 11. Specifically, the height control unit 173 (ECU 171) controls the spray height in accordance with the operation of the support mechanism 13, i.e., the operation of changing the distance between the ground contact surface of the wheel 12 and the vehicle body 11 (in other words, the operation of raising and lowering the wheel 12 relative to the vehicle body 11).

[0081] The function of the ECU 171 as the height control unit 173 will be described below. FIG. 9 is a front view illustrating the operation of the support mechanism and the height adjustment mechanism. FIG. 9 shows an example in which a work vehicle 10 travels across slopes G1, G2, changing the inclination angles θ1, θ2 of the slopes G1, G2 relative to the horizontal. The inclination angle θ1 of the slope G1 shown in FIG. 9(a) is larger than the inclination angle θ2 of the slope G2 shown in FIG. 9(b). Plants PL1, PL2 such as trees and grass are planted on both the left and right sides of the work vehicle 10, i.e., on the upper and lower sides of the slope. As the work vehicle 10 travels across the slopes G1, G2, it sprays liquid onto the plants PL1, PL2 using a spraying device 20.

[0082] As explained with reference to FIG. 7(a), when the work vehicle 10 travels on slopes G1 and G2, the support mechanism 13 operates under the horizontal control of the ECU 171 to shorten the distance (hereinafter, this distance will also be referred to as the "first distance") between the ground contact surface of one of the left and right wheels 12 (hereinafter, this wheel will also be referred to as the "first wheel 12A" (see FIG. 9)) located on the upper side of the slope (the right side of the figure) and the vehicle body 11, compared to when the work vehicle 10 travels on level ground. In other words, the support mechanism 13 raises the first wheel 12A relative to the vehicle body 11. The support mechanism 13 also operates to lengthen the distance (hereinafter, this distance will also be referred to as the "second distance") between the ground contact surface of the other of the left and right wheels 12 (hereinafter, this wheel will also be referred to as the "second wheel 12B" (see FIG. 9)) located on the lower side of the slope (the left side of the figure) and the vehicle body 11. In other words, the support mechanism 13 lowers the second wheel 12B relative to the vehicle body 11.

[0083] Meanwhile, through the height control of ECU 171, height adjustment mechanism 26 adjusts the spray height of spray device 20 located on the upper side of the slope (right side of the figure) (hereinafter, this spray device will also be referred to as the "first spray device (first working device) 20A" (see FIG. 9)) to match the height of plant PL1 on the same side. Also, height adjustment mechanism 26 adjusts the spray height of spray device 20 located on the lower side of the slope (left side of the figure) (hereinafter, this spray device will also be referred to as the "second spray device (second working device) 20B" (see FIG. 9)) to match the height of plant PL2 on the same side. The adjustment of the spray height by height adjustment mechanism 26 is performed as follows in accordance with the operation of support mechanism 13.

[0084] For example, a case will be described in which the inclination angle of slopes G1 and G2 changes from θ1 to θ2, causing the ground level on the upper side of the slope to decrease and the ground level on the lower side of the slope to increase. In order to maintain a constant attitude and height of vehicle body 11, ECU 171 performs horizontal control to cause support mechanism 13 to lower first wheel 12A located on the upper side of the slope relative to vehicle body 11 as shown by arrow b1, and to raise second wheel 12B located on the lower side of the slope relative to vehicle body 11 as shown by arrow b2.

[0085] When the inclination angles θ1, θ2 of the slopes G1, G2 change, the height of the ground where the wheels 12A, 12B touch the ground changes, and the heights of the plants PL1, PL2 planted on the ground also change accordingly. In this embodiment, the height control of the ECU 171 causes the first spray device 20A, which sprays liquid on the plant PL1 on the upper side of the slope, to descend relative to the vehicle body 11 as shown by arrow c1, and the second spray device 20B, which sprays liquid on the plant PL2 on the lower side of the slope, to ascend relative to the vehicle body 11 as shown by arrow c2.

[0086] That is, in this embodiment, when the support mechanism 13 lowers the first wheel 12A relative to the vehicle body 11 (when the first distance is increased), the height adjustment mechanism 26 lowers the spray height H of the first spray device 20A located on the same left-right side as the first wheel 12A. Also, when the support mechanism 13 raises the second wheel 12B relative to the vehicle body 11 (when the second distance is decreased), the height adjustment mechanism 26 raises the spray height of the second spray device 20B located on the same left-right side as the second wheel 12B.

[0087] Conversely to the above, when the inclination angle of slopes G2, G1 changes from θ2 to θ1, causing the ground level on the upper side of the slope to rise and the ground level on the lower side of the slope to fall, the support mechanism 13 and the height adjustment mechanism 26 perform the opposite operations to those described above. That is, in this case, the support mechanism 13 raises the first wheel 12A relative to the vehicle body 11 (shortens the first distance), and the height adjustment mechanism 26 raises the spray height H of the first spray device 20A located on the same left-right side as the first wheel 12A. In addition, the support mechanism 13 lowers the second wheel 12B relative to the vehicle body 11 (lengthens the second distance), and the height adjustment mechanism 26 lowers the spray height of the second spray device 20B located on the same left-right side as the second wheel 12B.

[0088] As described above, the heights of the first and second sprayers B1, B2 can be adjusted to match the heights of the plants PL1, PL2, which change depending on the height of the ground.

[0089] Furthermore, in orchards, the branches of many trees grow and spread out in all directions, forming a ceiling T (see FIG. 9) of branches throughout the orchard, and the spray height of the first and second spraying devices 20A, 20B may be limited by the ceiling T. In such cases, if the spray heights of the first and second spraying devices 20A, 20B do not change despite the height of the ceiling T being lowered due to a drop in ground level, the spraying device 20 may get caught on the ceiling T, hindering the movement of the work vehicle 10. This embodiment can eliminate such inconveniences.

[0090] As described above, the ECU 171 of the control device 17, by functioning as the attitude control unit 172, calculates the target actuation amount of the hydraulic cylinders 36, 37 of the support mechanism 13 based on the tilt attitude (tilt angle) of the loading unit 22 detected by the tilt sensor S4, and controls the extension / contraction amount of the hydraulic cylinders 36, 37 so that the actual actuation amount of the hydraulic cylinders 36, 37 detected by the stroke sensor S3 becomes the target actuation amount. In addition to this control, by functioning as the height control unit 173, the ECU 171 calculates the target actuation amount of the hydraulic cylinder 261 of the height adjustment mechanism 26 based on the actual actuation amount or target actuation amount of the hydraulic cylinders 36, 37, and controls the extension / contraction amount of the hydraulic cylinder 261 so that the actual actuation amount of the hydraulic cylinder 261 detected by the stroke sensor S8 becomes the target actuation amount. This allows the attitude control of the vehicle body 11 and the control of the spray heights of the first and second sprayers 20A, 20B to be executed in association with each other.

[0091] When the work vehicle 10 travels across a slope, then makes a U-turn and travels further across the upper or lower side of the slope than the previous location (round trip), the tilt angle of the vehicle body 11 is reversed in the left-right direction before and after the U-turn. For example, if the left side of the vehicle body 11 is located on the upper side of the slope and the right side is located on the lower side of the slope on the outbound journey, the left side of the vehicle body 11 will be located on the lower side of the slope and the right side will be located on the upper side of the slope on the return journey. Therefore, the support mechanism 13 operates to reverse the heights of the left and right wheels 12 before and after the U-turn. Furthermore, in connection with the operation of this support mechanism 13, the height adjustment mechanism 26 operates to reverse the spray heights of the left and right spray devices 20.

[0092] The height adjustment mechanism 26 can adjust the height of the spray unit 24 in accordance with the operation of both the front and rear support mechanisms 13 arranged on either the left or right side. For example, if the front and rear support mechanisms 13 operate differently and the front and rear wheels 12 arranged on either the left or right side are at different heights, the height adjustment mechanism 26 can be operated based on the midpoint height between the two wheels 12.

[0093] 2, the spray unit 24 of the spray device 20 of this embodiment is disposed at the front of the vehicle body 11, and is therefore susceptible to the height of the ground over which the front wheels 12 pass. Therefore, the height adjustment mechanism 26 of the spray device 20 may control the height of the spray unit 24 in response to the operation of the front left and right support mechanisms 13fR, 13fL. In other words, the height adjustment mechanism 26 may control the height of the spray unit 24 in response to the operation of the support mechanism 13 that supports the wheel 12 disposed closest to the spray unit 24.

[0094] As explained above, the work vehicle 10 of the embodiment comprises the vehicle body 11, the traveling device 19, the support mechanism 13 that supports the traveling device 19 and is capable of changing the distance L between the ground contact surface of the traveling device 19 and the vehicle body 11, the working device 20 that is attached to the vehicle body 11 and performs a predetermined task, and the height adjustment mechanism 26 that adjusts the working height of the working device 20. The height adjustment mechanism 26 adjusts the working height of the working device 20 in accordance with the operation of the support mechanism 13. In this way, by the support mechanism 13 changing the distance between the contact surface of the running device 19 and the vehicle body 11, the posture of the vehicle body 11, for example, the height and inclination (levelness) of the vehicle body 11 can be maintained at a predetermined level even if the height of the ground changes due to a change in the inclination angle of the ground, etc. Furthermore, when the attitude of the vehicle body 11 is controlled in accordance with changes in the height of the ground, the height (distance) of the working device 20 attached to the vehicle body 11 from the ground changes, but the height adjustment mechanism 26 can adjust the working height of the working device in accordance with changes in the height of the ground. Therefore, the work device 20 can be used to carry out work even on a slope where the entire surface is inclined.

[0095] The height adjustment mechanism 26 of the above embodiment lowers the working height of the working device 20 when the support mechanism 13 increases the distance between the ground contact surface of the traveling device 19 and the vehicle body 11, and raises the working height of the working device 20 when the support mechanism 13 decreases the distance between the ground contact surface of the traveling device 19 and the vehicle body 11. When the ground level changes to lower while the work vehicle 10 is traveling, the support mechanism 13 increases the distance between the ground contact surface of the travelling gear 19 and the vehicle body 11 in order to maintain the attitude of the vehicle body 11. When the ground level decreases and the attitude of the vehicle body 11 is maintained in this manner, the distance between the work implement 20 attached to the vehicle body 11 and the ground increases. Therefore, the height adjustment mechanism 26 lowers the working height of the work implement 20 so that it approaches the ground. Conversely, when the ground level changes to higher while the work vehicle 10 is traveling, the support mechanism 13 decreases the distance between the ground contact surface of the travelling gear 19 and the vehicle body 11 in order to maintain the attitude of the vehicle body 11. When the ground level increases and the attitude of the vehicle body 11 is maintained in this manner, the distance between the work implement 20 attached to the vehicle body 11 and the ground decreases. Therefore, the height adjustment mechanism 26 raises the working height of the work implement 20 so that it is away from the ground. In this way, the working height of the work implement 20 can be adjusted in accordance with changes in the ground level.

[0096] The traveling device 19 of the embodiment includes a first wheel 12A (see FIG. 9) arranged on one horizontal side (e.g., the right side) of the vehicle body 11 and a second wheel 12B (see FIG. 9) arranged on the other horizontal side (e.g., the left side), the working device 20 includes a first working device (e.g., the right working device) 20A (see FIG. 9) that performs work around the one side of the vehicle body 11, and the height adjustment mechanism 26 adjusts the working height of the first working device 20A in accordance with the operation of the support mechanism 13 to change the distance between the contact surface of the first wheel 12A and the vehicle body 11 (this distance is also referred to as the "first distance").

[0097] When the ground level differs between one horizontal side and the other horizontal side of the vehicle body 11 due to an inclination, the posture of the vehicle body 11 can be maintained by changing the distance between the ground contact surfaces of the first and second wheels 12A, 12B arranged on one side and the other side of the vehicle body 11 and the vehicle body 11. In addition, the working height of the first working device 20A, which performs work around one side of the vehicle body 11, can be adjusted in accordance with changes in the ground level on which the first wheel 12A travels.

[0098] The working device 20 in the embodiment includes a second working device (e.g., a left working device) 20B (see FIG. 9) that performs work on the other side of the vehicle body 11, and the height adjustment mechanism 26 adjusts the working height of the second working device 20B in response to the operation of the support mechanism 13 to change the distance (this distance is also referred to as the "second distance") between the ground contact surface of the second wheel 12B and the vehicle body 11. This makes it possible to adjust the working height of the second working device 20B that performs work on the other side of the vehicle body 11 in accordance with changes in the height of the ground on which the second wheel 12B travels.

[0099] [Variations] The above-described embodiments are illustrative in all respects and are not limiting. The scope of the present invention is defined by the claims rather than the above-described embodiments, and includes all modifications within the scope equivalent to the configurations described in the claims.

[0100] For example, the work vehicle 10 of the present disclosure can be modified as follows. (1) In the above embodiment, two working apparatuses 20 are arranged on both the left and right sides of the vehicle body 11, but this is not limited to this. For example, two working apparatuses 20 may be arranged side by side in the front and rear of the vehicle body 11. In this case, one of the front and rear working apparatuses 20 may perform work on the surroundings on one side in the left-right direction, and the other of the front and rear working apparatuses 20 may perform work on the surroundings on the other side in the left-right direction. Alternatively, in this case, the working apparatus 20 arranged on the front side may perform work on the front of the vehicle body 11, and the working apparatus 20 arranged on the rear side may perform work on the rear. The work vehicle 10 may be equipped with a single working apparatus 20. In this case, the single working apparatus 20 may perform work on both the left and right sides and / or both the front and rear sides.

[0101] (2) In the above embodiment, a case where the work vehicle 10 travels across a slope has been described with reference to Figure 9, but the working height of the work implement 20 can also be adjusted by the height adjustment mechanism 26 in accordance with the operation of the support mechanism 13 when the work vehicle 10 travels up and down a slope. In this case, the wheels 12 on one side, either the front or rear, constitute the first wheels 12A, and the wheels 12 on the other side, either the front or rear, constitute the second wheels 12B. Furthermore, the work implement 20 that performs work on the surroundings on one side, either the front or rear, constitutes the first work implement 20A, and the work implement 20 that performs work on the surroundings on the other side, either the front or rear, constitutes the second work implement 20B.

[0102] (3) In the above embodiment, the tanks 251 of the working device 20 are disposed on both the left and right sides of the vehicle body 11. However, they may be disposed on both the front and rear sides of the vehicle body 11.

[0103] (4) In the above embodiment, the support mechanism 13 performs attitude control (horizontal control) by changing the distance between the contact surface of the wheel 12 and the vehicle body 11. However, the vehicle body 11 itself may be given the function of attitude control (horizontal control). [Explanation of symbols]

[0104] 10: Work vehicle 11: Vehicle body 12: Wheels 12A: 1st wheel 12B: Second wheel 13:Support mechanism 19: Running gear 20: Spraying device (work device) 20A: 1st spray device (1st work device) 20B:Second spray device (second work device) 26: Height adjustment mechanism 251: Tank

Claims

1. The vehicle body, Running gear and a support mechanism that supports the traveling device and is capable of changing the distance between a ground contact surface of the traveling device and the vehicle body; a work device attached to the vehicle body and performing a predetermined task; a height adjustment mechanism for adjusting the working height of the working device, The height adjustment mechanism adjusts the working height of the work device in accordance with the operation of the support mechanism.

2. The work vehicle according to claim 1 , wherein the height adjustment mechanism adjusts the working height in response to an operation of the support mechanism to change the distance.

3. 3. The work vehicle according to claim 2, wherein the height adjustment mechanism lowers the working height when the support mechanism increases the distance, and raises the working height when the support mechanism decreases the distance.

4. the traveling device includes a first wheel disposed on one side of the vehicle body in a horizontal direction and a second wheel disposed on the other side, the work device includes a first work device that performs work around the one side of the vehicle body, 2. The work vehicle according to claim 1, wherein the height adjustment mechanism adjusts the working height of the first work device in response to an operation of the support mechanism to change a first distance between a ground contact surface of the first wheel and the vehicle body.

5. the work device includes a second work device that performs work on the periphery of the other side of the vehicle body, 5. The work vehicle according to claim 4, wherein the height adjustment mechanism adjusts the working height of the second work device in response to an operation of the support mechanism to change a second distance between a ground contact surface of the second wheel and the vehicle body.

6. 5. The work vehicle according to claim 4, wherein the height adjustment mechanism lowers the working height of the first work device when the support mechanism increases the first distance, and raises the working height of the first work device when the support mechanism decreases the first distance.

7. 6. The work vehicle according to claim 5, wherein the height adjustment mechanism lowers the working height of the second work device when the support mechanism increases the second distance, and raises the working height of the second work device when the support mechanism decreases the second distance.

8. The work vehicle according to any one of claims 1 to 7, further comprising a tank attached to the vehicle body and containing a liquid used in the work device.

9. A plurality of the tanks are provided, 9. The work vehicle according to claim 8, wherein the plurality of tanks are distributed between one side and the other side of the vehicle body in the horizontal direction.

Images