Work vehicle

Abstract

To provide a work vehicle capable of maintaining a posture of a link of a support mechanism even when an actuator stops functioning.SOLUTION: The utility vehicle 10 has a main body 11, a plurality of wheels 12 positioned at the front and rear of the left and right sides of the main body 11, a front support mechanism 31f having a swingable front link 13f and supporting the wheels 12 with respect to the main body 11, a rear support mechanism 31b having a swingable rear link 13b and supporting the wheels 12 with respect to the main body 11, a plurality of actuators 14 for swinging the front link 31f and the rear link 31b, and a detachable restrictor 60 capable of restricting the swinging of the front link 31f and the rear link 31b.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a work vehicle that travels on uneven road surfaces (uneven terrain). The work vehicle has a vehicle body, four wheels, and four support mechanisms that support the wheels relative to the vehicle body. The support mechanisms have an articulating link mechanism including a swingable link, and an actuator that operates the articulating link mechanism. The position of the wheels is changed by operating the articulating link mechanism. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-1440 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of the work vehicle, the actuator, which is a fluid cylinder, expands and contracts, causing the link to swing, generating operating force and supporting force for the support mechanism. For example, when the power supply to the work vehicle is turned off, the function of the actuator described above stops. If the actuator stops functioning and does not generate operating force or support force, for example, the weight of the vehicle body may cause the support mechanism to enter an unintended support state, resulting in the vehicle body assuming an unintended posture.

[0005] For example, if the actuator is not functioning, and no operating force or support force is generated in the front link of the front support mechanism that supports the front wheels, and the rear link of the rear support mechanism that supports the rear wheels (if the support force is lost), the weight of the vehicle body may cause the posture of the front link and rear link to change on their own, causing the vehicle body to drop and increasing the distance between the front and rear wheels. Therefore, the present disclosure provides a work vehicle that is capable of maintaining the posture of the link of the support mechanism even when the actuator is not functioning. [Means for solving the problem]

[0006] The work vehicle has a vehicle body, a plurality of wheels located at the front and rear of both the left and right sides of the vehicle body, a front support mechanism having a swingable front link and supporting the wheels relative to the vehicle body, a rear support mechanism having a swingable rear link and supporting the wheels relative to the vehicle body, a plurality of actuators for swinging the front link and the rear link, and a detachable regulating unit that can regulate the swinging of the front link and the rear link. [Effects of the Invention]

[0007] According to the work vehicle of the present disclosure, even if the actuator is out of function, it is possible to maintain the posture of the link that swings by the actuator. [Brief explanation of the drawings]

[0008] [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 an explanatory diagram showing a state in which the restricting unit is attached to a work vehicle. [Figure 6] FIG. 6 is an explanatory diagram showing a state in which a restricting section of another type is attached to a work vehicle. [Figure 7] FIG. 7 is an explanatory diagram showing a state in which the restricting unit is attached to a work vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0009] <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 comprises a vehicle body, a plurality of wheels located at the front and rear of both the left and right sides of the vehicle body, a front support mechanism having a swingable front link and supporting the wheels relative to the vehicle body, a rear support mechanism having a swingable rear link and supporting the wheels relative to the vehicle body, a plurality of actuators for swinging the front link and the rear link, and a detachable regulating unit that can regulate the swinging of the front link and the rear link.

[0010] The regulating unit attached to the work vehicle regulates the swinging of the front link and rear link, thereby maintaining the posture of the front link and rear link even when the actuator that operates the front link and rear link is stopped functioning. When the restricting portion is removed from the work vehicle, the restriction on the swinging of the front link and the rear link is released, and the front link and the rear link become able to swing.

[0011] (2) In the work vehicle of (1), the regulating part may be configured, for example, to have a rigid member that is not connected to the vehicle body but connects the front link and the rear link to each other, but the regulating part has a rigid member that connects the front link and the rear link to the vehicle body. The rigid members connect the front link and the rear link to the vehicle body, thereby restricting the swinging of the front link and the rear link.

[0012] (3) The work vehicle of (2) has a front support mechanism located at the front of the vehicle body and a rear support mechanism located at the rear of the vehicle body, and the regulating part has a first rigid member connecting the front link and the vehicle body and a second rigid member connecting the rear link and the vehicle body. The first rigid member connects the front link to the vehicle body, thereby restricting swinging of the front link. The second rigid member connects the rear link to the vehicle body, thereby restricting swinging of the rear link. It is possible to prevent a change (widening) in the front-to-rear distance between the wheel supported by the front support mechanism and the wheel supported by the rear support mechanism.

[0013] (4) In the work vehicle of (3), the vehicle body has a front bracket located at the front of the vehicle body for attaching the front support mechanism, and a rear bracket located at the rear of the vehicle body for attaching the rear support mechanism, the first rigid member connects the front link and the rear bracket, and the second rigid member connects the rear link and the front bracket. The first rigid member connects the front link to the rear bracket of the vehicle body. The second rigid member connects the rear link to the front bracket of the vehicle body. This makes it possible to prevent the change (widening) of the front-to-rear distance between the wheel supported by the front support mechanism and the wheel supported by the rear support mechanism.

[0014] (5) The work vehicle of (2) has the front support mechanism located at the front of the vehicle body and the rear support mechanism located at the rear of the vehicle body, and the regulating part has the rigid member that is detachably attached to the vehicle body, and the rigid member restrains the front link and the rear link relative to the vehicle body. The rigid member restricts the swinging of the front link and the rear link.

[0015] (6) In the work vehicle of (5), the vehicle body has a front bracket located at the front of the vehicle body for attaching the front support mechanism, and a rear bracket located at the rear of the vehicle body for attaching the rear support mechanism, and the rigid member connects the front bracket, the rear bracket, the front link, and the rear link. The front and rear brackets of the vehicle body are connected to the front and rear links by rigid members, which restricts the swinging of the front and rear links, making it possible to prevent the change (widening) of the distance in the fore-and-aft direction between the wheels supported by the front support mechanism and the wheels supported by the rear support mechanism.

[0016] (7) In any one of the work vehicles (1) to (6), the front support mechanism has a first front link attached to the vehicle body so as to be swingable around a first horizontal axis in the left-right direction, and a second front link attached to the first front link so as to be swingable around a second horizontal axis in the left-right direction. The rear support mechanism includes a first rear link attached to the vehicle body so as to be swingable about a third horizontal axis in the left-right direction, and a second rear link attached to the first rear link so as to be swingable about a fourth horizontal axis in the left-right direction. The wheel is attached to the second front link, and the wheel is attached to the second rear link, and the restricting portion is capable of restricting the swinging of the first front link and the first rear link.

[0017] The restricting portion restricts the swinging of the first front link and the first rear link, thereby making it possible to prevent the spacing between the front and rear wheels from changing (widening). Note that when the second front link and the second rear link are in a (relatively) laid-down position with a longitudinal component, the range of change (widening) of the spacing between the front and rear wheels is limited even if the second front link and the second rear link swing. Furthermore, when the actuator swings the second front link and the second rear link while the swinging of the first front link and the first rear link is restricted, the work vehicle can travel while following the road surface. When the first front link and the first rear link are in a (relatively) upright position with a vertical component and the regulating section regulates the swinging of the first front link and the first rear link, it is possible to ensure the ground clearance of the vehicle body without having to operate the actuators for the first front link and the first rear link.

[0018] (8) The work vehicle of (7) has a front support mechanism located at the front of the vehicle body and a rear support mechanism located at the rear of the vehicle body, and the regulating part has a first rigid member connecting the connection part between the first front link and the second front link to the vehicle body, and a second rigid member connecting the connection part between the first rear link and the second rear link to the vehicle body. The first rigid member and the second rigid member restrict the swinging of the first front link and the first rear link.

[0019] (9) The work vehicle of (7) has a front support mechanism located at the front of the vehicle body and a rear support mechanism located at the rear of the vehicle body, and the regulating part has a rigid member connecting the connection part between the first front link and the second front link, the connection part between the first rear link and the second rear link, and the vehicle body. The rigid member restricts the swinging of the first front link and the first rear link.

[0020] <Details of the embodiment of the present disclosure> Hereinafter, details of embodiments of the present disclosure will be described with reference to the drawings. Note that at least some of the embodiments described below may be combined in any manner.

[0021] [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 terrain).

[0022] 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 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 opposite side to the road surface.

[0023] The work vehicle 10 has a vehicle body 11, multiple wheels 12, multiple support mechanisms 13, and a control device 17. The work vehicle 10 of this embodiment has four wheels 12 and 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.

[0024] 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.

[0025] 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. The support mechanisms 13 have articulating link mechanisms 30 as operating parts that are operable to change the positions of the wheels 12. The wheels 12 are attached to the articulating link mechanisms 30. The support mechanisms 13 have actuators 14 that drive the articulating link mechanisms 30.

[0026] 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 work vehicle 10 has multiple 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 travel actuators that drive the wheels 12 to rotate.

[0027] 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 move. The work vehicle 10 has a plurality of training wheels 16. The training wheels 16 are attached midway along the articulating link mechanism 30. The training 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 training wheels 16 are driven wheels that can rotate freely.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] [Support mechanism 13] The left front support mechanism 13 and the right front support mechanism 13 are "front support mechanisms 13f" located at the front of the vehicle body 11. The left rear support mechanism 13 and the right rear support mechanism 13 are "rear support mechanisms 13b" located at the rear of the vehicle body 11. Although the front support mechanism 13f and the rear support mechanism 13b are attached in different directions on the left and right sides of the vehicle 10, they have the same configuration. The front support mechanism 13f and the rear support mechanism 13b will be collectively referred to as the "support mechanism 13," and the specific configuration of the support mechanism 13 will be described below.

[0032] 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 13 (front support mechanism 13f). 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.

[0033] In the following description (for example, in FIG. 5), when the support mechanism 13 is the front support mechanism 13f, the first link 31 is called the "first front link 31f" and the second link 32 is called the "second front link 32f." When the support mechanism 13 is the rear support mechanism 13b, the first link 31 is called the "first rear link 31b" and the second link 32 is called the "second rear link 32b."

[0034] A fixing bracket 23 is fixed to a part of a frame 21 of the vehicle body 11 (see FIG. 3). 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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 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.

[0039] 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 between the contact surfaces of the wheels 12 and the vehicle body 11.

[0040] [Sensor] The vehicle 10 has multiple sensors. Figure 4 is a control block diagram of the vehicle 10, and mainly shows the configuration related to the left front support mechanism 13 (front support mechanism 13f). Although the configuration of the other support mechanisms 13 is omitted in Figure 4, they have the same configuration as the left front support mechanism 13.

[0041] 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 an oil chamber on the head side of the second hydraulic cylinder 37. The rod side pressure sensor S2 detects the internal pressure of an oil chamber on the rod side of the second hydraulic cylinder 37. The control device 17 acquires detection signals from the sensors S1 and S2.

[0042] 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.

[0043] 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, and 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 the detection signal of the inclination sensor S4.

[0044] [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.

[0045] 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.

[0046] (Horizontal Control) The posture control unit 172 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 left and right front support mechanisms 13f and rear support mechanisms 13b so that the loading unit 22 is in a horizontal position. Based on the detection signal from the inclination sensor S4, the posture control unit 172 determines the tilt angles in the front-to-rear direction and the left-to-right direction, with the vehicle main body 11 (loading unit 22) in a reference position where the vehicle main body 11 is in a horizontal position. The posture control unit 172 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).

[0047] (Center of gravity control) The posture control unit 172 is capable of determining 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 performing center of gravity position control to control the operation of the left and right front support mechanisms 13f and rear support mechanisms 13b so that the center of gravity position is located in the center of the multiple (four) wheels 12 in a planar view.

[0048] The 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 a target center of gravity regardless of the unevenness of the road surface. As a variation of the center of gravity position control, the posture control unit 172 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 the detection signals of the pressure sensors S1 and S2. In this case, the posture control unit 172 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.

[0049] 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 posture control unit 172 can operate the support mechanism 13 so that the loading unit 22 (loading surface 221) is in a horizontal posture and so that all wheels 12 generate driving force in accordance with the uneven shape of the road surface.

[0050] [Regulatory section 60(1)] The front support mechanism 13f and rear support mechanism 13b of the work vehicle 10 (see FIG. 1) have hydraulic cylinder actuators 14. The extension and contraction of the actuators 14 causes the articulating link mechanisms 30 on the left and right sides of the vehicle body 11 to bend and extend, respectively, generating operating forces and support forces for the front support mechanism 13f and rear support mechanism 13b. Here, for example, if the power to the work vehicle 10 is turned off, no hydraulic oil is supplied to the actuator 14, and its function stops. Then, due to the weight of the vehicle body 11, the posture of the articulating link mechanisms 30 of the front support mechanism 13f and the rear support mechanism 13b may change on its own, causing the vehicle body 11 to descend and increasing the distance between the front and rear wheels 12.

[0051] Therefore, the work vehicle 10 has a restricting portion 60 that restricts a portion of the articulating link mechanism 30 of each of the front support mechanism 13f and the rear support mechanism 13b (see Figure 5). Figure 5 is an explanatory diagram showing the restricting portion 60 attached to the work vehicle 10. Figure 5, and Figures 6 and 7, which will be described later, are schematic diagrams. The restricting part 60 prevents the vehicle body 11 from descending and the gap between the front and rear wheels 12 from widening even when the actuator 14 is out of function, that is, when the hydraulic pressure of the actuator 14, which is a hydraulic cylinder, is lost.

[0052] The following describes a specific configuration of the regulating portion 60. For the purpose of describing the regulating portion 60, the support mechanisms 13 on each of the left and right sides of the vehicle body 11 will be described separately as a "front support mechanism 13f" located in the front part of the vehicle body 11 and a "rear support mechanism 13b" located in the rear part of the vehicle body 11.

[0053] As described above, the vehicle body 11 has the fixed brackets 23 fixed to the frame 21. The vehicle body 11 has, as the fixed brackets 23, a front bracket 23f located at the front of the vehicle body 11 and a rear bracket 23b located at the rear of the vehicle body 11. The front bracket 23f is a member for attaching the front support mechanism 13f, and like the frame 21, is made of metal and has high rigidity and strength. The rear bracket 23b is a member for attaching the rear support mechanism 13b, and like the frame 21, is made of metal and has high rigidity and strength.

[0054] The front support mechanism 13f has, as pivotable front links, a first front link 31f located on the vehicle body 11 side and a second front link 32f located on the wheel 12 side. The first front link 31f is attached to a front bracket 23f of the vehicle body 11 so as to be pivotable about a first horizontal axis X1 in the left-right direction. The second front link 32f is attached to the first front link 31f so as to be pivotable about a second horizontal axis X2 in the left-right direction. The wheel 12 is attached to the second front link 32f via a support bracket 33.

[0055] The rear support mechanism 13b has, as swingable rear links, a first rear link 31b located on the vehicle body 11 side and a second rear link 32b located on the wheel 12 side. The first rear link 31b is attached to a rear bracket 23b of the vehicle body 11 so as to be swingable about a third horizontal axis X3 in the left-right direction. The second rear link 32b is attached to the first rear link 31b so as to be swingable about a fourth horizontal axis X4 in the left-right direction. The wheel 12 is attached to the second rear link 32b via a support bracket 33.

[0056] The front support mechanism 13f has a first hydraulic cylinder 36 and a second hydraulic cylinder 37 (see FIG. 1). The first hydraulic cylinder 36 swings the first front link 31f, and the second hydraulic cylinder 37 swings the second front link 32f. The rear support mechanism 13b has a first hydraulic cylinder 36 and a second hydraulic cylinder 37. The first hydraulic cylinder 36 swings the first rear link 31b, and the second hydraulic cylinder 37 swings the second rear link 32b.

[0057] In the case of the work vehicle 10 shown in FIG. 5, the restricting portion 60 has a first rigid member 61 and a second rigid member 62. The first rigid member 61 and the second rigid member 62 are separate members. The first rigid member 61 connects the first front link 31f and the rear bracket 23b of the vehicle body 11. The second rigid member 62 connects the first rear link 31b and the front bracket 23f of the vehicle body 11. The first rigid member 61 and the second rigid member 62 are each straight members made of metal and have high rigidity. The restricting portion 60 shown in FIG. 5 has an X-shape formed by the first rigid member 61 and the second rigid member 62.

[0058] The restricting portion 60 shown in Figure 5 will be described in more detail. The first rigid member 61 connects the connecting portion between the first front link 31f and the second front link 32f to the rear bracket 23b. The connecting portion has a connecting structure using a second shaft (pin) 66a. The second shaft 66a has an elongated threaded shaft portion 661a. The shaft portion 661a passes through a first hole 67a formed in the first rigid member 61, and a nut is tightened onto the threaded portion.

[0059] The rear bracket 23b mounts the first rear link 31b so that the first rear link 31b can swing about the central axis of the third shaft 66b (third horizontal axis X3 in the left-right direction). The rear bracket 23b has a threaded shaft portion 661b extending from the third shaft 66b. The shaft portion 661b passes through a second hole 67b formed in the first rigid member 61, and a nut is tightened onto the threaded portion. In this way, the first rigid member 61 connects the first front link 31f and the rear bracket 23b.

[0060] The second rigid member 62 connects the connecting portion between the first rear link 31b and the second rear link 32b to the front bracket 23f. The connecting portion has a connecting structure using a fourth shaft (pin) 68a. The fourth shaft 68a has an elongated threaded shaft portion 681a. The shaft portion 681a passes through a second hole 69a formed in the second rigid member 62, and a nut is tightened onto the threaded portion.

[0061] The front bracket 23f mounts the first front link 31f so that the first front link 31f can swing about the central axis of the first shaft 68b (first horizontal axis X1 in the left-right direction). The front bracket 23f has a threaded shaft portion 681b extending from the first shaft 68b. The shaft portion 681b passes through a second hole 69b formed in the second rigid member 62, and a nut is tightened onto the threaded portion. In this way, the second rigid member 62 connects the first rear link 31b and the front bracket 23f.

[0062] The first rigid member 61 and the second rigid member 62 having the above-described configuration restrict the swinging of the first front link 31f and the first rear link 31b.

[0063] [Regulatory section 60(2)] Figure 6 is an explanatory diagram showing a state in which a restricting unit 60 of another form is attached to the work vehicle 10. The configuration of the work vehicle 10 shown in Figure 6 is the same as the configuration of the work vehicle 10 shown in Figures 1 to 5, except for the restricting unit 60. 6 has one rigid member 71 that is detachably attached to the vehicle body 11. The rigid member 71 restrains the first front link 31f and the first rear link 31b with respect to the frame 21.

[0064] The rigid member 71 is configured as a frame with a trapezoidal outline. The upper base of the trapezoid is longer than the lower base. The trapezoidal rigid member 71 connects the front bracket 23f, the rear bracket 23b, the first front link 31f, and the first rear link 31b at its four corners. The rigid member 71 is a metal frame member and has high rigidity.

[0065] The rigid member 71 shown in Fig. 6 will be described in detail. The rigid member 71 connects the connecting portion between the first front link 31f and the second front link 32f, the connecting portion between the first rear link 31b and the second rear link 32b, and the front bracket 23f and the rear bracket 23b of the frame 21.

[0066] The connection between the first front link 31f and the second front link 32f has a connection structure using a second shaft (pin) 66a, similar to the embodiment shown in Fig. 5. The second shaft 66a has an extended threaded shaft portion 661a. The shaft portion 661a passes through a first hole 67a formed in the rigid member 71, and a nut is tightened onto the threaded portion.

[0067] The connection between the first rear link 31b and the second rear link 32b has a connection structure using a fourth shaft (pin) 68a, similar to the embodiment shown in Fig. 5. The fourth shaft 68a has an extended threaded shaft portion 681a. The shaft portion 681a passes through a second hole 69a formed in the rigid member 71, and a nut is tightened onto the threaded portion.

[0068] The front bracket 23f mounts the first front link 31f so that the first front link 31f can swing about the central axis of the first shaft 68b (first horizontal axis X1 in the left-right direction). The front bracket 23f has a threaded shaft portion 681b extending from the first shaft 68b. The shaft portion 681b passes through a second hole 69b formed in the rigid member 71, and a nut is tightened onto the threaded portion. The rear bracket 23b mounts the first rear link 31b so that it can swing about the central axis of the third shaft 66b (third horizontal axis X3 in the left-right direction). The rear bracket 23b has a threaded shaft portion 661b extending from the third shaft 66b. The shaft portion 661b passes through a second hole 67b formed in the rigid member 71, and a nut is tightened onto the threaded portion.

[0069] In this way, the rigid member 71 connects the front bracket 23f, the rear bracket 23b, the first front link 31f, and the first rear link 31b. The single rigid member 71 restricts the swinging of the first front link 31f and the first rear link 31b.

[0070] [Regulatory section 60(1)(2)] The restricting portion 60 shown in each of FIGS. 5 and 6 is detachable from the vehicle body 11, and when attached to the vehicle body 11, the restricting portion 60 restricts the swinging of the first front link 31f and the first rear link 31b. In the embodiment shown in FIG. 5, the restricting portion 60 has the first rigid member 61 and the second rigid member 62 as rigid members that connect the first front link 31f and the first rear link 31b to the vehicle main body 11, respectively, as described above. In the case of the embodiment shown in FIG. 6, the restricting portion 60 has one rigid member 71 that connects the first front link 31f and the first rear link 31b to the vehicle main body 11, as described above.

[0071] The restricting unit 60 attached to the vehicle 10 restricts the swinging of the first front link 31f and the first rear link 31b, so that the postures of the first front link 31f and the first rear link 31b are maintained even when the actuator (first hydraulic cylinder 36) that operates the first front link 31f and the first rear link 31b is out of function. As a result, it is possible to prevent the spacing between the front and rear wheels 12 from changing (widening).

[0072] 5 and 6, the restricting portion 60 restricts the swinging of the first front link 31f and the first rear link 31b when the first front link 31f and the first rear link 31b are in a position where they are close to each other. Therefore, the swinging of the first front link 31f and the first rear link 31b is restricted while the distance between the front and rear wheels 12 is kept small. As a result, the small distance between the front and rear wheels 12 is maintained.

[0073] 5 and 6, the vehicle 10 is in a lying position with the longitudinal direction of the second front link 32f and the longitudinal direction of the second rear link 32b including a longitudinal component. In this state, the restricting unit 60 restricts the swinging of the first front link 31f and the first rear link 31b. When the power to the vehicle 10 is turned off, the actuator 14 stops functioning and the second front link 32f and the second rear link 32b lose their supporting force. Therefore, even if the second front link 32f and the second rear link 32b swing freely, the range of change (range of increase) in the spacing between the front and rear wheels 12 is limited. In other words, the change (expansion) in the spacing between the front and rear wheels 12 is suppressed.

[0074] Furthermore, even if the restricting unit 60 restricts the swinging of the first front link 31f and the first rear link 31b, it does not restrict the swinging of the second front link 32f and the second rear link 32b. The second hydraulic cylinder 37 (see FIG. 1) can swing the second front link 32f and the second rear link 32b from the states shown in Figures 5 and 6, respectively. This allows the work vehicle 10 to travel in a manner that follows the road surface, even if the road surface is uneven.

[0075] Figure 7 is an explanatory diagram showing the restricting unit 60 attached to the work vehicle 10. Figure 7 shows the restricting unit 60 attached to the vehicle body 11, restricting the swinging of the first front link 31f and the first rear link 31b. Note that the restricting unit 60 shown in Figure 7 has a first rigid member 61 and a separate second rigid member 62, similar to the restricting unit 60 shown in Figure 5, but the lengths are different.

[0076] In the configuration shown in Figure 7, the longitudinal direction of the first front link 31f and the longitudinal direction of the first rear link 31b have an up-down component, and the regulating portion 60 regulates the swinging of the first front link 31f and the first rear link 31b in a relatively upright position. In this case, it is possible to ensure the ground clearance of the vehicle body 11 even without causing the actuator 14 (first hydraulic cylinder 36) for the first front link 31f and the first rear link 31b to function.

[0077] As described above, the restricting unit 60 is attached to the work vehicle 10 by fastening the bolts, and can be removed from the work vehicle 10 by removing the bolts. The bolt-fastened configuration allows the restricting unit 60 to be easily attached to and detached from the work vehicle 10. When the restricting portion 60 is removed from the vehicle 10, the restriction on the swinging of the first front link 31f and the first rear link 31b is released, and the first front link 31f and the first rear link 31b become swingable.

[0078] 〔others〕 6 has a trapezoidal outline and a frame shape formed by four linear plate portions 72 that form the four sides. As a modification, the plate portion 72 that corresponds to the upper base of the trapezoid may be omitted. Furthermore, the regulating unit 60 may be configured to regulate the swinging of the first front link 31f and the first rear link 31b, and although not shown, may be configured, for example, to have a rigid member that is not connected to the vehicle body 11 but connects the first front link 31f and the first rear link 31b to each other.

[0079] 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. [Explanation of symbols]

[0080] 10 Work vehicle 11 Vehicle body 12 wheels 13f Front support mechanism 13b Rear support mechanism 14 Actuators 23f Front Bracket 23b Rear bracket 31f First previous link (previous link) 31b First link (following link) 32f Second previous link 32b Second link 60 Regulatory Department 61 First rigid member 62 Second rigid member 71 Rigid Member X1 First horizontal axis center X2 Second horizontal axis center X3 Third horizontal axis center X4 Fourth Horizontal Axis Core

Claims

1. The vehicle body, a plurality of wheels located at the front and rear of both the left and right sides of the vehicle body; a front support mechanism having a swingable front link and supporting the wheels with respect to the vehicle body; a rear support mechanism having a swingable rear link and supporting the wheel with respect to the vehicle body; a plurality of actuators for swinging the front link and the rear link; a detachable restricting portion that restricts the swinging of the front link and the rear link; A work vehicle having the above.

2. The restricting portion includes a rigid member connecting the front link and the rear link to the vehicle body. The work vehicle according to claim 1.

3. The vehicle has a front support mechanism located at a front portion of the vehicle body and a rear support mechanism located at a rear portion of the vehicle body, The restriction portion includes a first rigid member connecting the front link and the vehicle body, and a second rigid member connecting the rear link and the vehicle body. The work vehicle according to claim 2.

4. the vehicle body has a front bracket located at a front portion of the vehicle body for attaching the front support mechanism, and a rear bracket located at a rear portion of the vehicle body for attaching the rear support mechanism, the first rigid member connects the front link and the rear bracket; the second rigid member connects the rear link and the front bracket; The work vehicle according to claim 3.

5. The vehicle has a front support mechanism located at a front portion of the vehicle body and a rear support mechanism located at a rear portion of the vehicle body, the restricting portion has the rigid member detachably attached to the vehicle body, The work vehicle according to claim 2 , wherein the rigid member restrains the front link and the rear link relative to the vehicle body.

6. the vehicle body has a front bracket located at a front portion of the vehicle body for attaching the front support mechanism, and a rear bracket located at a rear portion of the vehicle body for attaching the rear support mechanism, the rigid member connects the front bracket, the rear bracket, the front link, and the rear link; A work vehicle according to claim 5.

7. The front support mechanism includes: a first front link attached to the vehicle body so as to be swingable about a first horizontal axis in the left-right direction; a second front link attached to the first front link so as to be swingable about a second horizontal axis in the left-right direction; and The rear support mechanism includes: a first rear link attached to the vehicle body so as to be swingable about a third horizontal axis in the left-right direction; a second rear link attached to the first rear link so as to be swingable about a fourth horizontal axis in the left-right direction; and The wheel is attached to the second front link, The wheel is attached to the second rear link, The restricting portion is capable of restricting the swinging of the first front link and the first rear link. A work vehicle according to any one of claims 1 to 6.

8. The vehicle has a front support mechanism located at a front portion of the vehicle body and a rear support mechanism located at a rear portion of the vehicle body, The restriction portion is a first rigid member connecting a connecting portion between the first front link and the second front link and the vehicle main body; a second rigid member connecting a connecting portion between the first rear link and the second rear link and the vehicle main body; 8. The work vehicle according to claim 7, comprising:

9. The vehicle has a front support mechanism located at a front portion of the vehicle body and a rear support mechanism located at a rear portion of the vehicle body, The restriction portion is a rigid member connecting a connecting portion between the first front link and the second front link, a connecting portion between the first rear link and the second rear link, and the vehicle main body; A work vehicle according to claim 7.

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