Work vehicle and connection device

Abstract

A work vehicle 10 comprises a vehicle body 11, travel devices 12 for causing the vehicle body 11 to travel, and a connection device 15 for connecting a work machine 19 to the vehicle body 11. The connection device 15 includes an attachment unit 18 for attaching the work machine 19 to the vehicle body 11 in a liftable manner, and a motor 74 for outputting power to the work machine 19. The motor 74 is attached to the attachment unit 18, and the attachment unit 18 lifts and lowers the motor 74 together with the work machine 19.

Description

Work vehicle and coupling device

[0001] The present invention relates to a work vehicle used for performing operations such as agricultural work, and a coupling device for coupling a work implement to the work vehicle. This application claims priority based on Japanese Application No. 2024-226369 filed on December 23, 2024, and incorporates all the contents described in the Japanese application. This application claims priority based on Japanese Application No. 2024-226256 filed on December 23, 2024, and incorporates all the contents described in the Japanese application. This application claims priority based on Japanese Application No. 2024-226304 filed on December 23, 2024, and incorporates all the contents described in the Japanese application. This application claims priority based on Japanese Application No. 2024-226378 filed on December 23, 2024, and incorporates all the contents described in the Japanese application.

[0002] Patent Document 1 discloses a work vehicle having a three-point link at the rear. The three-point link couples a work implement for performing agricultural work such as tilling to the work vehicle. The three-point link has a function of raising and lowering the work implement according to the work.

[0003] Japanese Unexamined Patent Application Publication No. 2004-000225

[0004] The work vehicle includes a vehicle body, a traveling device for traveling the vehicle body, and a coupling device for coupling a work implement to the vehicle body. The coupling device includes a mounting unit that mounts the work implement to the vehicle body so as to be movable up and down, and a motor that outputs power to the work implement. The motor is attached to the mounting unit, and the mounting unit raises and lowers the motor together with the work implement.

[0005] A coupling device for coupling a work implement to a work vehicle includes a mounting unit that mounts the work implement to the work vehicle so as to be movable up and down, and a motor that outputs power to the work implement. The motor is attached to the mounting unit, and the mounting unit raises and lowers the motor together with the work implement.

[0006] The work vehicle comprises a vehicle body and a running gear for moving the vehicle body. The vehicle body comprises an operating device protruding from the upper part of the vehicle body and a fixing part for attaching a coupling device for connecting work equipment to the vehicle body. The fixing part is located below the operating device and extends from the vehicle body toward the coupling device.

[0007] The work vehicle comprises a vehicle body, a travel device that enables the vehicle body to travel in at least three directions of travel, and a fixed part to which another device can be attached and to which power energy can be output to the other device, wherein the fixed part is provided at each of the positions corresponding to the at least three directions of travel.

[0008] The work vehicle comprises a vehicle body and a running gear for moving the vehicle body. The vehicle body has a fixing section for attaching other equipment to be attached and detached. The fixing section comprises a vehicle-side coupling for connecting one or both of the pipes and wiring, a cover, and a cover actuator for switching the cover between a first state and a second state. In the first state, the cover covers the connection port side of the vehicle-side coupling of the fixing section, and in the second state, it leaves the connection port side of the vehicle-side coupling of the fixing section open.

[0009] Figure 1 is a perspective view showing one embodiment of the work vehicle. Figure 2 is a perspective view of the work vehicle. Figure 3 is a plan view of the work vehicle shown in Figure 2. Figure 4 is a left side view of the work vehicle shown in Figure 2. Figure 5 is a right side view of the work vehicle shown in Figure 2. Figure 6 is a configuration diagram of the work vehicle. Figure 7 is a schematic diagram showing a modified work vehicle. Figure 8 is a schematic diagram showing a modified work vehicle. Figure 9 is a schematic diagram showing a modified work vehicle. Figure 10 is a schematic diagram showing a modified work vehicle. Figure 11 is a perspective view showing the rear of the vehicle body and the coupling device shown in Figure 2. Figure 12 is a perspective view showing the coupling device detached from the vehicle body. Figure 13 is a perspective view of the coupling device as seen from the work vehicle side. Figure 14 is a perspective view of the coupling device as seen from the work machine side (rear side). Figure 15 is an explanatory diagram of the rear of the work vehicle. Figure 16 is an explanatory diagram showing the cover in its first state. Figure 17 is an explanatory diagram showing a modified example of the cover. Figure 18 is an explanatory diagram showing a modified example of the cover. Figure 19 is a schematic diagram showing another example of a work vehicle. Figure 20 is a schematic diagram showing yet another example of a work vehicle. Figure 21 is a schematic diagram showing yet another example of a work vehicle. Figure 22 is a perspective view showing one embodiment of a work vehicle (third invention). Figure 23 is a perspective view of a work vehicle (third invention). Figure 24 is a top view of the work vehicle shown in Figure 23. Figure 25 is a left side view of the work vehicle shown in Figure 23. Figure 26 is a right side view of the work vehicle shown in Figure 23.

[0010] <<First Invention>> <Problems to be Solved by the First Invention> The (conventional) work vehicle described above has an output shaft (PTO shaft: power take-off shaft), and the rotational force of the output shaft is supplied to the work implement. The output shaft is provided protruding rearward from a gearbox mounted on the rear of the work vehicle. The rotational force of the output shaft is obtained from a drive source such as an engine or motor mounted on the work vehicle. The work implement moves up and down relative to the work vehicle by a three-point linkage, but the output shaft does not move up or down. For this reason, a power transmission mechanism with a complex configuration, such as a universal joint with an extension and retraction function, is required between the work implement and the output shaft.

[0011] The first invention aims to provide a work vehicle that can simplify the connection structure between a work implement and a part that outputs power to the work implement, and a connecting device for connecting a work implement to the work vehicle.

[0012] <Effects of the First Invention> According to the first invention, it is possible to simplify the connection structure between the work machine and the part (motor) that outputs power to the work machine.

[0013] <Outline of Embodiments of the First Invention> The outline of embodiments of the first invention is listed below. (1) The work vehicle of this embodiment comprises a vehicle body, a traveling device for moving the vehicle body, and a coupling device for connecting a work machine to the vehicle body, the coupling device comprises a mounting unit for attaching the work machine to the vehicle body so that it can be raised and lowered, and a motor for outputting power to the work machine, the motor is attached to the mounting unit, and the mounting unit raises and lowers the motor together with the work machine.

[0014] In the aforementioned work vehicle, the coupling device for connecting the work equipment to the vehicle body has a motor, and the output of this motor is used to power the work equipment. Therefore, a separate motor for work power is not required for the work vehicle or the work equipment. Moreover, the motor is attached to a mounting unit of the coupling device, and the motor moves up and down together with the work equipment by this mounting unit. As a result, the coupling structure between the work equipment and the motor is simplified.

[0015] (2) In the work vehicle described in (1) above, the mounting unit is detachable from the vehicle body. The coupling device is detachable from the vehicle body.

[0016] (3) In the work vehicle described in (1) or (2) above, the vehicle body comprises a central frame and a pair of side frames located on both sides of the central frame and displaceable relative to the central frame, and the running gear is attached to each of the pair of side frames and has displacement actuators that allow the side frames to be displaced relative to the central frame in at least one of the following directions: front-rear direction, left-right direction, and up-down direction. For example, the vehicle body deforms according to the shape of the road surface on which it is traveling. The work vehicle can travel according to the shape of the road surface and have the work machine perform work.

[0017] (4) In any one of the work vehicles described in (1) to (3) above, the vehicle body comprises a central frame having a battery and a case for housing the battery, and a pair of side frames located on both sides of the central frame to which the running gear is attached, wherein the case is housed in the central frame and is displaceable in the front-rear direction. The work vehicle (vehicle body) deforms as the case is displaced in the front-rear direction.

[0018] (5) The coupling device of this embodiment is a coupling device for coupling a work machine to a work vehicle, and comprises a mounting unit for attaching the work machine to the work vehicle so that it can be raised and lowered, and a motor that outputs power to the work machine, wherein the motor is attached to the mounting unit, and the mounting unit raises and lowers the motor together with the work machine.

[0019] The coupling device for connecting the work equipment to the vehicle body has a motor, and the output of this motor is used to power the work equipment. Therefore, the work vehicle and work equipment do not need separate motors for power. Moreover, the motor is attached to a mounting unit on the coupling device, and the motor moves up and down together with the work equipment by this mounting unit. This simplifies the coupling structure between the work equipment and the motor.

[0020] (6) In the coupling device described in (5), the mounting unit is detachable from the work vehicle. The coupling device is detachable from the work vehicle.

[0021] (7) In the coupling device of (5) or (6) above, the mounting unit has a first mounting portion to be attached to the work vehicle, a second mounting portion to which the work machine is attached, and a lifting mechanism to raise and lower the second mounting portion and the motor relative to the first mounting portion. The mounting unit can be easily attached by attaching the first mounting portion to the work vehicle. The work machine can be easily attached by attaching the work machine to the second mounting portion.

[0022] (8) In the coupling device of (7) above, the lifting mechanism comprises a link mechanism and an actuator, the link mechanism comprises an upper link member and a lower link member, the first end of which is attached to the first mounting portion and the second end of which is attached to the second mounting portion, and the actuator drives the lower link member or the upper link member up and down relative to the first mounting portion. The link mechanism makes it possible to configure the lifting mechanism in a compact manner.

[0023] (9) Any one of the coupling devices described in (5) to (8) above has an inverter that outputs power to the motor. The motor's rotation is controlled by the inverter mounted on the coupling device. Furthermore, if the specifications of the motor, such as the output, are to be changed according to the work equipment, for example, if the inverter is mounted inside the work vehicle, this work would be relatively difficult. In contrast, by mounting the inverter on the coupling device, the work of changing the specifications as described above becomes easier.

[0024] (10) The coupling device of (7) has an inverter that outputs power to the motor, and the lifting mechanism has a link mechanism and an actuator, the link mechanism has an upper link member and a lower link member, the first end of which is attached to the first mounting part and the second end of which is attached to the second mounting part, the actuator drives the lower link member or the upper link member up and down relative to the first mounting part, and a coupling that connects the electrical wiring connected to the motor and the electrical wiring connected to the inverter is attached to the upper link member. The link mechanism makes it possible to configure the lifting mechanism compactly. The fact that the coupling is attached to the upper link member makes maintenance such as replacing the inverter or motor easier.

[0025] (11) In the coupling device of (8) or (10) above, the link mechanism comprises the upper link member and two lower link members located below the upper link member and on both sides of the upper link member in a plan view, and the motor is located below the upper link member and between the two lower link members. The motor is located in the space formed below the upper link member and between the two lower link members. Space is effectively utilized and the coupling device can be made compact.

[0026] (12) In the coupling device of (9) or (10) above, when the direction of travel of the work vehicle is defined as the front in the front-rear direction, and the horizontal direction perpendicular to the front-rear direction is defined as the left-right direction, the motor is located in the center in the left-right direction, and the inverter is located on the left or right side in the left-right direction. This makes it possible to make the coupling device more compact in the front-rear direction.

[0027] (13) The coupling device described in (7), (8), or (10) has an inverter that outputs power to the motor, the inverter is mounted on the first mounting part, and the motor is mounted on the second mounting part. The motor is mounted on the second mounting part and moves up and down, while the inverter is mounted on the first mounting part which is fixed to the work vehicle and does not move up and down. The load on the lifting mechanism is reduced.

[0028] (14) The coupling device described in (7), (8), (10), or (13) is located on the side of the first mounting portion and has a coupling for connecting one or both of the liquid piping and electrical wiring. When the coupling device is attached to the work vehicle, the coupling facilitates the connection of necessary connections between the coupling device and the work vehicle, such as hydraulic piping, liquid piping for the work machine, electrical wiring for the motor, or electrical wiring for the work machine.

[0029] (15) In the coupling device of (7), (8), (10), (13) or (14) above, the first mounting portion has a mounting frame that is long in the vertical direction, including an upper fixing member and a lower fixing member that connect to a fixing portion of the work vehicle, and the mounting frame has an opening that penetrates in the front-rear direction from the work vehicle side to the work machine side. The mounting frame of the first mounting portion is connected by the upper fixing member and the lower fixing member at the upper and lower positions of the fixing portion of the work vehicle, making the connection strong. Even if the mounting frame is large in the vertical direction, wiring or piping can be done between the work vehicle and the coupling device through the opening.

[0030] (16) In the coupling device of (7), (8), (10), (13), (14) or (15) above, the second mounting portion has a hitch frame that facilitates the attachment and detachment of the implement. The hitch frame is, for example, common to the hitch frame mounted on a conventional tractor. In this case, conventional implements can be attached, and the attachment and detachment of the implement is made easy.

[0031] <<Second Invention>> <Problems to be Solved by the Second Invention> With the (conventional) work vehicle described above, it is possible to connect a work machine (tiller) that performs work such as tilling to a work area such as farmland, which is useful. However, in addition to the three-point linkage, various equipment is mounted on the rear of the work vehicle. When the various parts are close together, maintenance of them may not be easy. The purpose of the second invention is to provide a work vehicle that can connect a work machine that performs work such as tilling to a work area such as farmland, and that enables improved maintenance performance.

[0032] <Effects of the Second Invention> According to the second invention, the maintenance performance of the work vehicle is improved.

[0033] <Outline of Embodiments of the Second Invention> The outline of embodiments of the second invention will be described below. (1) The work vehicle of this embodiment comprises a vehicle body and a running device for moving the vehicle body, the vehicle body comprises an operating device provided protruding from the upper part of the vehicle body and a fixing part for attaching a coupling device for connecting work equipment to the vehicle body, the fixing part is located below the operating device and extends from the vehicle body toward the coupling device.

[0034] It is possible to connect a work machine (a tiller) used for tasks such as plowing in a work area, such as farmland, to the fixed part of the vehicle body via a coupling device. A space is created between the upper operating equipment and the lower fixed part, and this space can be used to perform maintenance on the operating equipment, the fixed part, or the vehicle body. If the operating equipment were installed inside the vehicle body, maintenance such as adjustment of the operating equipment may be difficult. However, since the operating equipment is installed protruding from the top of the vehicle body, it is easy for workers to access the operating equipment and perform maintenance.

[0035] (2) The work vehicle described in (1) above has a coupling device for connecting the work machine to the vehicle body, and the coupling device has a lifting mechanism for raising and lowering the work machine. The operating equipment, which is provided protruding from the top of the vehicle body, and the fixing part for attaching the coupling device are separated in the vertical direction, so a space is provided between them. This space is used as space for raising and lowering the work machine by the coupling device attached to the fixing part.

[0036] (3) In the work vehicle described in (1) or (2) above, the operating equipment is equipment for operating the work machine or the coupling device. The equipment (operating equipment) includes, for example, a relief valve of a hydraulic unit. When a work machine is connected to the vehicle body via a coupling device, it may be necessary to adjust the relief pressure using the relief valve depending on the specifications of the work machine. In this case, since the relief valve is provided protruding from the top of the vehicle body, it is easy for the operator to access the relief valve and perform maintenance.

[0037] (4) In any one of the work vehicles described in (1) to (3) above, the fixed part is located at the lower part of the vehicle body and has a frame that extends in the front-rear direction and protrudes from the lower part, and a mounting block located at the front of the frame to which the coupling device is attached. The lower part of the vehicle body is extended by the frame. The coupling device is attached to the mounting block at the front of the frame. The mounting position of the coupling device is separated from the vehicle body in the front-rear direction. As a result, a large vertical space is provided between the fixed part and the coupling device and the operating equipment located above them. This space is used as space for raising and lowering the work machine by the coupling device.

[0038] (5) In any one of the work vehicles described in (1) to (4) above, the operating equipment and the fixed part are arranged to overlap in a plan view, at least in part. Neither the operating equipment nor the fixed part protrudes excessively, making it possible to make the work vehicle more compact.

[0039] (6) In any one of the work vehicles described in (1) to (5) above, the fixed part comprises a frame located at the lower part of the vehicle body and extending in the front-rear direction and protruding from the lower part, and a mounting block located at the front of the frame and to which the coupling device is attached, wherein the mounting block has a vehicle-side coupling for connecting one or both of the piping and wiring, and the frame has an opening through which one or both of the piping and wiring extending from the vehicle-side coupling towards the vehicle body passes. For example, piping extending from an operating unit including the operating equipment is connected to the vehicle-side coupling through the opening in the frame.

[0040] (7) In any one of the work vehicles described in (1) to (6) above, the running gear is arranged on both the left and right sides of the vehicle body, and the mounting positions of the fixing part and the coupling device overlap with a part of the running gear when viewed from the side. The fixing part does not protrude in the front-rear direction from the running gear.

[0041] (8) In any one of the work vehicles described in (1) to (7) above, the running gear has wheels positioned on the front, rear, left, and right sides of the vehicle body, and the mounting position of the fixing part and the coupling device overlaps with the wheels in a side view. The fixing part does not protrude further than the wheels in the front-rear direction.

[0042] (9) The work vehicle described in (7) above has the coupling device for connecting the work machine to the vehicle body, and the mounting positions of the coupling device and the work machine do not overlap with the running gear when viewed from the side. Space is provided on both the left and right sides of the coupling device, and this space is used as space for the work machine.

[0043] (10) In any one of the work vehicles (1) to (9) above, the vehicle body has a central frame and a pair of side frames located on both sides of the central frame and displaceable relative to the central frame. The traveling device is attached to each of the pair of side frames and has a displacement actuator that enables the central frame and the side frames to be displaced relative to each other in at least one of the left-right direction and the up-down direction. For example, the vehicle body is deformed according to the shape of the road surface on which it travels. The work vehicle can cause another device such as a work implement to perform work while traveling according to the shape of the road surface.

[0044] (11) In any one of the work vehicles (1) to (10) above, the vehicle body has a central frame having a battery and a case for housing the battery, and a pair of side frames located on both sides of the central frame and to which the traveling device is attached. The case is displaceable in the front-rear direction and is housed in the central frame. When the case is displaced in the front-rear direction, the work vehicle (vehicle body) is deformed.

[0045] <<Third Invention>> <Problem to be Solved by the Third Invention> The above-described (conventional) work vehicle has an output shaft (PTO shaft: power take-off shaft), and the rotational force of the output shaft is applied to the work implement. The output shaft is provided to protrude rearward from a gearbox mounted at the rear of the work vehicle. The rotational force of the output shaft is obtained from a drive source such as an engine or a motor mounted on the work vehicle.

[0046] Development has been carried out on a work vehicle that can be connected to a work implement at the rear of the work vehicle and, while the work vehicle is towing the work implement, not only enables the work implement to perform work but also allows for variations in the positional relationship between the work vehicle and the work implement and causes the work implement to perform work. The third invention aims to provide a work vehicle that can travel together with another device such as a work implement for performing work such as agricultural work and can cause the other device to function.

[0047] <Effect of the Third Invention> The work vehicle can travel together with another device, and can cause the other device to function by outputting power energy to the other device.

[0048] <Outline of Embodiment of Third Invention> The outline of the embodiment of the third invention will be listed and described below. (1) The work vehicle of the present embodiment includes a vehicle body, a traveling device that enables the vehicle body to travel in at least three traveling directions, and a fixing portion that can attach another device to the vehicle body and can output power energy to the other device. The fixing portion is provided at each position corresponding to the at least three traveling directions.

[0049] The work vehicle travels in at least three traveling directions together with another device attached to the fixing portion. The fixing portion is provided at each position corresponding to at least three traveling directions of the vehicle body. Each fixing portion can cause the other device to function by outputting power energy to the other device to be attached. Note that the power energy includes at least one of electrical energy such as electric power, physical energy such as rotational force, and energy by hydraulic pressure. The "position corresponding to the traveling direction" may include a position on the traveling direction side or a position on the opposite side of the traveling direction.

[0050] (2) In the work vehicle of (1) above, at least one fixing portion is provided at the position on the traveling direction side. For example, when the traveling direction of the vehicle body is forward, the "position on the traveling direction side" is the front position, and when the traveling direction of the vehicle body is right, the "position on the traveling direction side" is the right position. (3) In the work vehicle of (2) above, at least one fixing portion is provided at the position on the opposite side of the traveling direction. For example, when the traveling direction of the vehicle body is forward, the "position on the opposite side of the traveling direction" is the rear position, and when the traveling direction of the vehicle body is right, the "position on the opposite side of the traveling direction" is the left position. (4) In the work vehicle of (2) or (3) above, at least one fixing portion is provided at a position different from the position corresponding to the traveling direction.

[0051] In the work vehicles of (2) and (4) above, at least one fixing part is provided on the side facing the direction of travel, and at least one more fixing part is provided at a position different from the position corresponding to the direction of travel (the position on the side facing the direction of travel and the position on the opposite side). In the work vehicle of (3) above, at least one fixing part is provided on the side facing the direction of travel, at least one fixing part is provided at a position opposite to the direction of travel, and at least one more fixing part is provided at a position different from the position corresponding to the direction of travel (the position on the side facing the direction of travel and the position on the opposite side).

[0052] (5) In any one of the work vehicles described in (1) to (4) above, the other equipment is a work implement or a coupling device for attaching a work implement. It is possible to directly connect a work implement, for example, to a work area such as farmland, to a fixed part of the vehicle body. Alternatively, it is possible to connect the work implement to a fixed part of the vehicle body via a coupling device.

[0053] (6) In any one of the work vehicles described in (1) to (5) above, the at least three directions of travel are at least three of the forward, backward, left, and right directions. If another device is attached to a fixed part at the front of the vehicle body, the work vehicle can, for example, push the other device while traveling forward, and the other device can operate in front of the work vehicle. If another device is attached to a fixed part at the rear of the vehicle body, the work vehicle can, for example, tow the other device while traveling forward, and the other device can operate behind the work vehicle. If another device is attached to a fixed part at the left or right of the vehicle body, the work vehicle can, for example, travel forward with the other device on the left or right, and the other device can operate at the left or right of the work vehicle.

[0054] (7) In any one of the work vehicles described in (1) to (6) above, the vehicle body further has the fixing portion at one or both of the upper and lower positions of the vehicle body. It is also possible to attach other equipment to the fixing portion provided at one or both of the upper and lower positions of the vehicle body.

[0055] (8) Any one of the work vehicles described in (1) to (7) above outputs the power energy to each of the multiple other devices attached to the multiple fixed parts. One work vehicle can be fitted with multiple other devices, and these multiple other devices can operate simultaneously, resulting in high efficiency.

[0056] (9) In any one of the work vehicles described in (1) to (8) above, the vehicle body comprises a central frame and a pair of side frames located on both sides of the central frame and displaceable relative to the central frame, the running gear comprises front and rear wheels attached to each of the pair of side frames, and the fixing part is provided on one or both of the pair of side frames. The central frame and the side frames are displaced relative to each other, making it possible to deform the vehicle body. With the vehicle body deformed, it is possible to attach other equipment to the fixing part provided on one or both of the left and right side frames.

[0057] (10) In any one of the work vehicles described in (1) to (9) above, the fixed part has a vehicle-side coupling for connecting one or both of the piping and wiring. When it is necessary to connect piping and wiring between the other equipment and the vehicle body, the vehicle-side coupling makes it easier to attach the other equipment to the work vehicle.

[0058] (11) In any one of the work vehicles described in (1) to (10) above, the other device has either or both a drive unit for operating the other device and a drive unit for operating yet another device attached via the other device, and the vehicle body has a power source for supplying power to the drive unit. The vehicle body has a power source for supplying power to the drive unit, but does not require a drive unit such as an actuator for operating the other device, thereby simplifying the vehicle body.

[0059] (12) Any one of the work vehicles described in (1) to (11) above has a coupling device which can be attached to the fixed part as another piece of equipment and to which a work machine can be attached, and the coupling device has a lifting mechanism for raising and lowering the work machine and a motor which outputs power to the work machine. The vehicle body does not require a motor and inverter for operating the work machine, and furthermore, it does not require a lifting mechanism for raising and lowering the work machine. This makes it possible to simplify the vehicle body.

[0060] (13) In any one of the work vehicles described in (1) to (12) above, the vehicle body comprises a central frame and a pair of side frames located on both sides of the central frame and displaceable relative to the central frame, and the running gear is attached to each of the pair of side frames and has displacement actuators that allow the central frame and the side frames to be displaced relative to each other in at least one of the left-right and up-down directions. For example, the vehicle body deforms according to the shape of the road surface on which it is traveling. The work vehicle can operate other equipment while traveling according to the shape of the road surface.

[0061] (14) In any one of the work vehicles described in (1) to (13) above, the vehicle body comprises a central frame having a battery and a case for housing the battery, and a pair of side frames located on both sides of the central frame to which the running gear is attached, wherein the case is housed in the central frame and is displaceable in the front-rear direction. The work vehicle (vehicle body) deforms as the case is displaced in the front-rear direction.

[0062] <<Fourth Invention>> <Problems to be Solved by the Fourth Invention> The (conventional) work vehicle described above has an output shaft (PTO shaft: power take-off shaft), and the rotational force of the output shaft is supplied to the work machine. The output shaft is provided protruding rearward from a gearbox mounted on the rear of the work vehicle. The rotational force of the output shaft is obtained from a drive source such as an engine or motor mounted on the work vehicle. In addition, power lines for supplying power from the work vehicle to the work machine, or signal lines for controlling the operation of the work machine, may also be provided.

[0063] Such work vehicles are often used in outdoor environments with a lot of foreign matter, such as farms, where there is a lot of dust and other debris. Terminals are provided on the work vehicle for wiring power lines or signal lines, and if foreign matter adheres to the terminals, malfunctions may occur. Therefore, the fourth invention aims to provide a work vehicle that can be fitted with other equipment such as work machines and that can prevent malfunctions that occur when used in environments with a lot of foreign matter.

[0064] <Effects of the Fourth Invention> According to the fourth invention, even when a work vehicle is used in an outdoor environment with a lot of foreign matter such as soil dust and dirt, such as a farm, the fixed parts of the work vehicle are protected by the cover, making it possible to prevent malfunctions.

[0065] <Outline of Embodiments of the Fourth Invention> The outline of embodiments of the fourth invention is listed below. (1) The work vehicle of this embodiment comprises a vehicle body and a running device for moving the vehicle body, the vehicle body having a fixing part for attaching other equipment to a detachable part, the fixing part comprising a vehicle-side coupling for connecting one or both of the pipes and wiring, a cover, and a cover actuator for switching the cover between a first state and a second state, the cover covering the connection port side of the vehicle-side coupling of the fixing part in the first state, and opening the connection port side of the vehicle-side coupling of the fixing part in the second state.

[0066] When another device is attached to the vehicle's mounting point, the cover actuator sets the cover to the second state, and the mounting point is left open. When no other device is attached to the vehicle's mounting point, the cover actuator sets the cover to the first state, and the mounting point is covered by the cover. Having the cover in the first state provides a good appearance and prevents foreign matter from adhering to the mounting point, including the vehicle-side coupling. Even when the work vehicle is used in an outdoor environment with a lot of foreign matter such as soil and dust, such as a farm, the mounting point of the work vehicle is protected by the cover, preventing malfunctions.

[0067] (2) In the work vehicle described in (1), the cover actuator starts operating when predetermined conditions are met. The cover is opened and closed automatically. (3) In the work vehicle described in (2), the predetermined conditions are conditions relating to the state or operation of the vehicle body, conditions relating to the positional relationship between the vehicle body and the other equipment, or conditions relating to the identification of the other equipment.

[0068] (4) In any one of the work vehicles described in (1) to (3) above, the cover actuator operates to open and close the cover when the vehicle body and the other equipment change relative positions, while the other equipment is not attached to the fixed part.

[0069] (5) In any one of the work vehicles described in (1) to (4) above, when the vehicle body proceeds to an operation step for connecting to the other equipment or an operation step after disconnecting from the other equipment, according to the set operation program, the cover actuator starts to operate.

[0070] (6) In any one of the work vehicles described in (1) to (5) above, the vehicle body has a detection device, and when the detection device detects the other equipment or identification information of the other equipment, the cover actuator starts to operate.

[0071] (7) In any one of the work vehicles described in (1) to (6) above, the fixing part has a coupling part for mechanically connecting the other equipment, and the cover covers the vehicle-side coupling and the coupling part. The cover can cover the fixing part completely.

[0072] (8) In any one of the work vehicles described in (1) to (7) above, the fixed part has a storage section for storing the cover in the second state. When another device is attached to the fixed part, the cover in the second state is stored away, resulting in a good appearance.

[0073] (9) In any one of the work vehicles described in (1) to (8) above, the other equipment is a work implement or a coupling device for attaching a work implement. It is possible to directly connect a work implement, for example, to a work area such as farmland, to a fixed part of the vehicle body. Alternatively, it is possible to connect the work implement to a fixed part of the vehicle body via a coupling device.

[0074] (10) In any one of the work vehicles described in (1) to (9) above, the vehicle body comprises a central frame and a pair of side frames located on both sides of the central frame and displaceable relative to the central frame, and the traveling device is attached to each of the pair of side frames and has displacement actuators that allow the central frame and the side frames to be displaced relative to each other in at least one of the left-right and up-down directions. For example, the vehicle body deforms according to the shape of the road surface on which it is traveling. The work vehicle can travel according to the shape of the road surface while allowing other equipment, such as a work machine, to perform work.

[0075] (11) In any one of the work vehicles described in (1) to (10) above, the vehicle body comprises a central frame having a battery and a case for housing the battery, and a pair of side frames located on both sides of the central frame to which the running gear is attached, wherein the case is housed in the central frame and is displaceable in the front-rear direction. The vehicle body may be deformed by the displacement of the case housed in the central frame in the front-rear direction.

[0076] <Details of Embodiments> The details of embodiments of the invention (the first invention, the second invention, the third invention, and the fourth invention) will be described below with reference to the drawings. At least some of the embodiments described below may be combined in any way.

[0077] [Overall Configuration of the Work Vehicle] Figures 1 and 2 are perspective views showing one embodiment of the work vehicle. This work vehicle 10 has an exterior member 9, and Figure 2 shows the exterior member 9 removed. The exterior member 9 is attached to the frames 20 and 21 of the work vehicle 10. The exterior member 9 protects the various pieces of equipment on the work vehicle 10 and also enhances its aesthetic appearance. Figures 3, 4, and 5 are a plan view, left side view, and right side view of the work vehicle 10 shown in Figure 2. Figure 6 is a diagram showing the configuration of the work vehicle 10.

[0078] The work vehicle 10 has a running gear 12 and travels on road surfaces such as fields and roads. In the case of the work vehicle 10 of this embodiment, the direction pointed to by arrow X1 in each figure is the basic direction of travel and is defined as "forward". In each figure, the direction pointed to by arrow X2 is the opposite direction of the basic direction of travel and is defined as "rear". In each figure, the direction pointed to by arrow Y1 is defined as "left", the direction pointed to by arrow Y2 is defined as "right", the direction pointed to by arrow Z1 is defined as "up", and the direction pointed to by arrow Z2 is defined as "down".

[0079] The work vehicle 10 is capable of moving straight in both forward and backward directions, as well as turning left and turning right, thanks to its running gear 12. The running gear 12 is located at four points on the front, rear, left, and right of the vehicle body 11, and each running gear 12 has wheels 25. The work vehicle 10 has a hydraulic motor, which allows the direction of the wheels 25 (the direction in which the wheels 25 roll) to be changed within a 360-degree range. Therefore, the work vehicle 10, which can move forward and backward, can move straight in all 360 degrees. Note that an electric motor may be used instead of the hydraulic motor. Alternatively, the work vehicle 10 may be capable of changing the direction of the wheels 25 from the basic direction of travel within a range of 0 to 90 degrees, for example, by a hydraulic cylinder. When the direction of the wheels 25 changes by 90 degrees from the basic direction of travel, their rolling direction becomes either left or right. The work vehicle 10 can also move straight in either left or right. Furthermore, the work vehicle 10 may be able to change the direction of its wheels 25 within a range of 0 to -90 degrees using the hydraulic cylinder, from its initial state in the basic direction of travel. Since the direction of the wheels 25 can be changed within a range of 0 to 90 degrees and within a range of 0 to -90 degrees from its initial state in the basic direction of travel, and since it is possible to move forward and backward, the work vehicle 10 can move in a straight line in all 360 degrees.

[0080] The work vehicle 10 connects to the work machine 19 via a coupling device 15. Figures 1, 2, 4, and 5 show the work machine 19 as a dashed line. The work machine 19 has a configuration and functions for performing various tasks. The tasks performed by the work machine 19 include, but are not limited to, agricultural work, industrial work (civil engineering, construction, etc.), and transportation work. The work vehicle 10 travels together with the work machine 19, while the work machine 19 performs its tasks.

[0081] In this embodiment, the work performed by the implement 19 is agricultural work. The implement 19 includes, for example, a spraying device for applying fertilizer or chemicals to a field, a seeding device for sowing seeds, a tilling device for cultivating the soil, a tilling device for tilling the soil, a weeding device for weeding, a soil mounding device for mounding soil, and so on. The implement 19 is replaced according to the required work.

[0082] The configuration of each part of the work vehicle 10 will now be described. The work vehicle 10 has one vehicle body 11 and four running devices 12 for moving the vehicle body 11. The work vehicle 10 in this embodiment has a coupling device 15 attached to the vehicle body 11. The coupling device 15 is a device for connecting a work machine 19 to the vehicle body 11. The coupling device 15 has a lifting mechanism 70 for raising and lowering the work machine 19. The specific configuration of the coupling device 15 will be described later.

[0083] The coupling device 15 allows the work equipment 19 to be detached. The work vehicle 10 allows the coupling device 15 to be detached. If the work equipment 19 is not needed for the work vehicle 10, the work equipment 19 is detached from the coupling device 15. Furthermore, the coupling device 15 may be detached from the vehicle body 11. The work vehicle 10 can run with the coupling device 15 mounted, even though the work equipment 19 has been detached, and the work vehicle 10 can also run with not only the work equipment 19 but also the coupling device 15 detached from the vehicle body 11.

[0084] The vehicle body 11 has a central frame 20 and a pair of side frames 21, 21 located on the left and right sides of the central frame 20. The left side frame 21 may be described as "21L" and the right side frame 21 as "21R". The running gear 12, including the wheels 25, is mounted on the side frames 21. Each of the pair of side frames 21, 21 is displaceable relative to the central frame 20, and the work vehicle 10 can be deformed according to the work content or operating conditions such as the shape of the road surface.

[0085] Figures 7, 8, 9, and 10 are schematic diagrams showing a deformed work vehicle 10. As shown in Figures 7 and 8, the central frame 20 and the left side frame 21L and the right side frame 21R are each displaceable relative to each other in the left-right and up-down directions. The left side frame 21L and the right side frame 21R are each displaceable independently. The work vehicle 10 has displacement actuators 13 that allow the central frame 20 and the side frames 21L and 21R to be displaced relative to each other in the left-right and up-down directions.

[0086] The work vehicle 10 has left and right actuators 131 and up and down actuators 132 as displacement actuators 13. The left and right actuators 131 (see Figure 7) extend and retract, displacing the side frames 21L and 21R, respectively, in the left and right directions relative to the central frame 20. As a result, the work vehicle 10 changes the distance between the left and right wheels 25 according to the width of the furrows in the field, for example, and travels.

[0087] The vertical actuator 132 (see Figure 8) extends and retracts, displacing the central frame 20 vertically relative to the side frames 21L and 21R. The central frame 20 becomes higher than the side frames 21L and 21R. As a result, the work vehicle 10 changes the position of the central frame 20 vertically according to the height of the furrows in the field, for example, and travels while straddling the furrows.

[0088] The central frame 20 and the side frames 21L and 21R each only need to be displaceable in at least one of the left-right and up-down directions relative to each other. To this end, the work vehicle 10 only needs to have displacement actuators 13 in the direction that allows the side frames 21L and 21R to be displaced.

[0089] The deformation of the vehicle body 11 in the longitudinal direction occurs within the central frame 20. That is, as shown in Figure 10, the central frame 20 mounts the battery 16 (first battery 16A) and the case 205 that houses the battery 16. The case 205 can be displaced in the longitudinal direction by the longitudinal actuators 133. The battery 16 (first battery 16A) is heavy. As the battery 16 (first battery 16A) is displaced in the longitudinal direction within the central frame 20, the vehicle body 11 deforms, and its center of gravity can be changed. For example, when the work vehicle 10 travels on an inclined surface, it changes its center of gravity depending on its posture or depending on the work machine 19 it is connected to.

[0090] As another example of deformation of the work vehicle 10 in the longitudinal direction (see Figure 9), the work vehicle 10 may have front and rear actuators 133 as displacement actuators 13, and the front and rear actuators 133 may extend and retract to relatively displace the central frame 20 and the side frames 21L and 21R, respectively, in the longitudinal direction. By displacing the central frame 20 in the longitudinal direction, the center of gravity of the vehicle body 11 can be changed.

[0091] As shown in Figures 7 and 8, the central frame 20 and the side frames 21L and 21R are each relatively displaceable in at least one of the left-right and up-down directions. The displacement actuator 13 displaces the central frame 20 and the side frames 21L and 21R relatively in at least one of the left-right and up-down directions. As shown in Figure 10, the central frame 20 has a case 205 that houses the battery 16 (first battery 16A). The case 205 is displaceable in the front-rear direction and is housed in the central frame 20. The displacement actuator 13 displaces the case 205 in the front-rear direction within the central frame 20.

[0092] Each of the above-described forms of work vehicle 10 deforms its vehicle body 11 according to, for example, the shape of the road surface it is traveling on. The work vehicle 10 can operate with the work machine 19 while traveling with the vehicle body 11 deformed.

[0093] The work vehicle 10 (see Figures 2 to 5) has four running gears 12 located on the front, rear, left, and right sides of the vehicle body 11. The running gears 12 are attached to each of the left and right pair of side frames 21. The left front running gear 12 may be described as "12LF", the right front running gear 12 as "12RF", the left rear running gear 12 as "12LR", and the right rear running gear 12 as "12RR".

[0094] Each running gear 12 has wheels 25, a motor 26 for driving, a reduction gear 27, and a power transmission unit 28 including gears and a shaft. The rotational force of the motor 26 is reduced by the reduction gear 27, and the reduced power is transmitted to the wheels 25 through the power transmission unit 28, causing the wheels 25 to rotate. As a result, the work vehicle 10 moves.

[0095] The left front running gear 12LF and the left rear running gear 12LR are mounted on the left side frame 21L, and together they constitute the left running unit UL. The left running unit UL includes the left second battery 16L, a sub-junction box 24L, and inverters 31 connected to the front and rear running motors 26, respectively, which are mounted on the side frame 21L. The right front running gear 12RF and the right rear running gear 12RR are mounted on the right side frame 21R, and together they constitute the right running unit UR. The right running unit UR includes the right second battery 16R, a sub-junction box 24R, and inverters 31 connected to the front and rear running motors 26, respectively, which are mounted on the side frame 21R. The central frame 20 mounts the first battery 16A, a hydraulic unit 17, and a main junction box 24A, etc., and together they constitute the central unit UC. In this embodiment, as described above (see Figure 10), the case 205 housing the first battery 16A is displaced in the front-rear direction within the central frame 20. In contrast, the hydraulic unit 17 and other equipment, including the main junction box 24A, are not displaced in the front-rear direction.

[0096] The work vehicle 10 has steering actuators 29 that change the rolling direction of each of the four wheels 25 of the running gear 12 (see Figure 3). In this embodiment, the running gear 12 is supported by the side frame 21 and is pivotable around its vertical axis. The steering actuators 29 are mounted between the side frame 21 and the running gear 12. The steering actuators 29 change the orientation of the running gear 12 by extending and retracting. This changes the rolling direction of the wheels 25, and thus changes the direction of travel of the work vehicle 10.

[0097] The work vehicle 10 includes a control device 14, a battery 16, a hydraulic unit 17, and a cooling unit 23. The control device 14 controls the operation of each component of the work vehicle 10, such as the travel device 12 (motor 26), displacement actuator 13, steering actuator 29, hydraulic unit 17, and cooling unit 23.

[0098] Battery 16 is a rechargeable battery that can be discharged and recharged. Battery 16 supplies power to each piece of equipment on the work vehicle 10. In this embodiment (see Figure 6), the work vehicle 10 has one first battery 16A and two second batteries 16L and 16R. The first battery 16A is mounted on the central frame 20. One second battery 16L is mounted on the left side frame 21L, and the other second battery 16R is mounted on the right side frame 21R.

[0099] In this embodiment, the displacement actuator 13 and the steering actuator 29 are composed of hydraulic cylinders. The hydraulic unit 17 generates hydraulic pressure to extend and retract the hydraulic cylinders. The hydraulic unit 17 includes a tank for storing hydraulic fluid, a hydraulic pump, a motor 171 for driving the hydraulic pump, various valves, and hydraulic piping. The hydraulic unit 17 is mounted at the rear of the central frame 20.

[0100] The coupling device 15 (see Figure 4) has a hydraulic cylinder 811 as an actuator for raising and lowering the work equipment 19. The hydraulic unit 17 of the vehicle body 11 has hydraulic piping for supplying hydraulic pressure to the coupling device 15 (hydraulic cylinder 811). Furthermore, when the work equipment 19 is operated hydraulically, the hydraulic unit 17 has hydraulic piping for supplying hydraulic pressure to the work equipment 19. These hydraulic pipes (liquid pipes 36, see Figure 12) are connected to the vehicle-side coupling 44 of the vehicle body 11. The vehicle-side coupling 44 is located at the rear of the vehicle body 11 (central frame 20) and is provided at the lower fixing portion 41.

[0101] When the coupling device 15 is attached to the fixing part 41 of the vehicle body 11, the coupling 88 (see Figure 13) of the coupling device 15 is connected to the vehicle-side coupling 44. The hydraulic piping (pipe 89) of the coupling device 15 is connected to the coupling 88, and hydraulic fluid from the hydraulic unit 17 is supplied to the hydraulic cylinder 811 of the coupling device 15 and the hydraulic equipment of the work machine 19 through the hydraulic piping (liquid piping 36, pipe 89).

[0102] The cooling unit 23 (see Figure 3) includes a first cooling unit 231 for cooling the battery 16 (16A, 16L, 16R), a second cooling unit 232 for cooling the motor 171 that drives the hydraulic pump of the hydraulic unit 17, and a third cooling unit 233 for cooling the motor 26 of the traveling device 12. Each cooling unit has a heat exchanger or the like for cooling the cooling medium.

[0103] The first cooling unit 231 and the second cooling unit 232 are mounted on the central frame 20 and are located in front of the first battery 16A. The third cooling unit 233 is mounted on the front of the side frames 21L and 21R, respectively. In this embodiment, the first cooling unit 231 is air-cooled, while the second cooling unit 232 and the third cooling unit 233 are water-cooled.

[0104] The work vehicle 10 (see Figure 6) has a junction box 24 and inverters 31 connected to each motor. In this embodiment, the junction box 24 has a main junction box 24A and sub-junction boxes 24L and 24R. The main junction box 24A is mounted on the central frame 20. The sub-junction boxes 24L and 24R are mounted on the side frames 21L and 21R. Each inverter 31 receives power from the main junction box 24A or the sub-junction boxes 24L and 24R and outputs a predetermined amount of power to each motor.

[0105] The work vehicle 10 has a charging port 32, a DC-DC converter 33, and an OBC / DC-DC converter 34. The DC-DC converter 33 transforms (steps down or steps up) the power supplied from the battery 16A to supply to other electrical equipment such as the control device 14. The OBC / DC-DC converter 34 includes an onboard charger and a DC-DC converter. The OBC / DC-DC converter 34 is connected to the charging port 32. The charging port 32 is mounted on the vehicle body 11 and is connected to an external power source located at a charging station or the like. The OBC / DC-DC converter 34 converts the power supplied from the charging port 32 into power to charge the battery 16A.

[0106] [Mounting Structure of the Coupling Device 15] As described above (see Figure 2), the work machine 19 is attached to the vehicle body 11 via the coupling device 15. The configuration for attaching the coupling device 15 to the vehicle body 11 will now be described. Figure 11 is a perspective view showing the rear of the vehicle body 11 and the coupling device 15 as shown in Figure 2. Figure 12 is a perspective view showing the coupling device 15 detached from the vehicle body 11. The vehicle body 11 has a fixing part 41 for attaching the coupling device 15 in a detachable manner. The fixing part 41 has a frame 42 and a mounting block 43.

[0107] The frame 42 is located at the lower part 201 of the vehicle body 11 and protrudes rearward from the lower part 201. Due to the configuration of this frame 42, the fixing part 41 extends from the vehicle body 11 toward the coupling device 15. The frame 42 is fixed to the lower part 201 of the central frame 20. Like the central frame 20, the frame 42 is made of metal and has high rigidity. The frame 42 is provided extending rearward from the lower part 201, and its shape is longer in the front-to-back direction than in the vertical direction. The frame 42 is constructed by combining multiple beam members and has a rectangular parallelepiped shape. The mounting block 43 is located at the rear end of the frame 42. The mounting block 43 is fixed to the frame 42 by welding or the like. The mounting block 43 is the part to which the coupling device 15 is attached.

[0108] As will be explained later, the coupling device 15 has a lifting mechanism 70 for raising and lowering the work machine 19, as well as a first mounting section 71 and a second mounting section 72. The first mounting section 71 is the part that is attached to the work vehicle 10. In other words, the first mounting section 71 is attached to the mounting block 43 of the fixing section 41. The second mounting section 72 is the part to which the work machine 19 is attached.

[0109] As shown in Figure 12, the mounting block 43 has a vehicle-side coupling 44. One or both of the liquid piping 36 and electrical wiring 37 extending from each piece of equipment mounted on the work vehicle 10 are connected to the vehicle-side coupling 44. In this embodiment, both the liquid piping 36 and electrical wiring 37 are connected to the vehicle-side coupling 44. The mounting block 43 has a recess 431 that opens to the rear, and the vehicle-side coupling 44 is provided in the recess 431. The coupling 88 of the coupling device 15, which will be described later, is connected to the vehicle-side coupling 44 (see Figure 13).

[0110] The liquid piping 36 consists of a hydraulic pipe 361 extending from the hydraulic unit 17 and a liquid pipe 362 for the work machine 19. The hydraulic fluid sent from the hydraulic unit 17 flows through the hydraulic pipe 361 and is supplied from the vehicle-side coupling 44 to the hydraulic cylinder 811 of the lifting mechanism 70 of the coupling device 15. If the work machine 19 is, for example, a spraying device that sprays a liquid (chemicals or water), the liquid piping 362 is the piping for supplying that liquid to the work machine 19. A tank (not shown) for storing the liquid may be mounted on the vehicle body 11. The liquid piping 362 extending from the tank is connected to the vehicle-side coupling 44. The liquid in the liquid piping 362 is supplied from the vehicle-side coupling 44 to the work machine 19 through a relay pipe (not shown) of the coupling device 15.

[0111] The electrical wiring 37 includes, for example, a power wire 371 and a signal wire 372 for sensors, etc. The power wire 371 is a wire that supplies power from the battery 16 (first battery 16A) of the vehicle body 11 to the coupling device 15 and the work machine 19 via the vehicle-side coupling 44. When the work machine 19 requires power, the power from the battery 16 is supplied to the work machine 19 from the vehicle-side coupling 44 to which the power wire 371 is connected, via the wires of the lifting mechanism 70 (not shown).

[0112] The signal line 372 is an electrical wire that connects the control device 14 of the vehicle body 11 to the vehicle-side coupling 44. If the work equipment 19 attached to the coupling device 15 has a sensor (not shown), the signal from that sensor is sent to the control device 14 through the signal line (not shown) of the coupling device 15 and the signal line 372 connected to the vehicle-side coupling 44. Based on this signal, the control device 14 performs control related to the work of the work equipment 19. For example, the lifting mechanism 70 is used to change the height of the work equipment 19.

[0113] The frame 42 of the fixed part 41 has an opening 421 through which piping or wiring extending from the vehicle-side coupling 44 to the vehicle body 11 passes. The piping is the liquid piping 36, and the wiring is the electrical wiring 37. In this embodiment, both the liquid piping 36 and the electrical wiring 37 pass through the opening 421. As described above, the frame 42 is constructed by combining a plurality of beam members, so the space between these beam members becomes the opening 421. In this embodiment, the opening 421 through which the liquid piping 36 and the electrical wiring 37 pass is provided at the top of the frame 42. In other words, the frame 42 is constructed by four beam members that extend in the front-rear direction, located vertically and horizontally. The space between the two upper beam members becomes the opening 421 through which the liquid piping 36 and the electrical wiring 37 pass. The liquid piping 36, such as hydraulic piping, and the electrical wiring 37 extending from the hydraulic unit 17 are connected to the vehicle-side coupling 44 through the opening 421 of the frame 42. The liquid piping 36 and electrical wiring 37 may pass through openings on the sides of the frame 42.

[0114] The position of the fixing part 41 in the work vehicle 10 will now be described. The vehicle body 11 (see Figures 4 and 5) has an operating device 35 that protrudes horizontally from its upper part 111. In this embodiment, the operating device 35 is provided to protrude rearward from the upper part 111.

[0115] The operating device 35 is part of the equipment used to operate the work machine 19 or the coupling device 15. In this embodiment, the operating device 35 is part of the equipment of the hydraulic unit 17, and that equipment is a valve unit. The valve unit protrudes rearward from the upper part 111. The valve unit (operating device 35) is supported by a support member 202 of the central frame 20. The valve unit (operating device 35) includes a relief valve for releasing pressure in the event that excessive pressure occurs in the hydraulic piping.

[0116] When connecting a work implement 19 to the vehicle body 11 via a coupling device 15, for example, it may be necessary to adjust the relief pressure using the relief valve depending on the specifications of the work implement 19. Since the relief valve is provided protruding from the upper part 111 of the vehicle body 11, the operator can easily access the relief valve, making adjustment and maintenance easy. If the operating equipment 35, such as the relief valve, were provided inside the vehicle body 11, it may be difficult to adjust and maintain the operating equipment 35.

[0117] As shown in Figures 4, 5, and 11, the fixed part 41 is provided below the operating device (valve unit) 35. The fixed part 41 is positioned vertically apart from the operating device 35. This configuration provides a space S1 between the upper operating device 35 and the lower fixed part 41. This space S1 makes it possible to perform maintenance on the operating device 35, the fixed part 41 (vehicle-side coupling 44), or the rear equipment 39 on the vehicle body side. Furthermore, the space S1 facilitates the attachment and detachment of the coupling device 15 to the fixed part 41.

[0118] As described above, the fixing part 41 has a frame 42 that is long in the front-rear direction and protrudes from the lower part 201 of the vehicle body 11. The frame 42 extends the lower part of the vehicle body 11 in the rearward direction, and the coupling device 15 is attached to the mounting block 43 at the front end of the frame 42. As a result, the mounting position P1 of the coupling device 15 is moved away from the vehicle body 11 in the rearward direction. The space S1 provided between the fixing part 41 and the coupling device 15 and the operating equipment 35 located above them is widened in the vertical and front-rear directions. The space S1 is used as space for raising and lowering the work machine 19 by the coupling device 15.

[0119] As shown in the plan view of Figure 3 and the perspective view of Figure 12, the entire fixed part 41 overlaps with the operating device 35 located above it in a plan view. However, the operating device 35 and the fixed part 41 may be arranged to overlap in a plan view, at least in part. This arrangement prevents either the operating device 35 or the fixed part 41 from protruding excessively in the rearward direction, making the work vehicle 10 more compact.

[0120] The running gear 12, which has wheels 25, is located on both the left and right sides of the vehicle body 11. As shown in the side views of Figures 4 and 5, the mounting position P1 between the fixing part 41 and the coupling device 15 overlaps with a part of the rear running gear 12 in a side view. The mounting position P1 is the position in the front-rear direction of the joint surface between the fixing part 41 and the coupling device 15, and specifically (see Figure 12) is the position of the rear surface of the mounting block 43. The fixing part 41 does not protrude further rearward than the rear running gear 12. As shown in the side views of Figures 4 and 5, the mounting position P1 between the fixing part 41 and the coupling device 15 overlaps with the two rear wheels 25 in a side view. In other words, the mounting position P1 is located between the left and right wheels 25. The fixing part 41 does not protrude further rearward than the wheels 25.

[0121] The mounting position P2 between the coupling device 15 and the work machine 19 is located behind the rear running gear 12 (wheels 25) in a side view. The mounting position P2 is the position in the front-rear direction of the joint surface between the coupling device 15 and the work machine 19, and specifically (see Figure 11) is the position of the rear surface of the second mounting portion 72 of the coupling device 15. Even when the vertically swinging work machine 19 is in its furthest forward position, the mounting position P2 is located behind the rear running gear 12 (wheels 25) in a side view and does not overlap with the rear running gear 12 (wheels 25). Due to this mounting position P2, a space S2 (see Figure 3) is provided on both the left and right sides of the coupling device 15, and this space S2 is used, for example, as space for the work machine 19.

[0122] [Coupling device 15] The coupling device 15 is a device for connecting a work machine 19 (see Figure 2) to a work vehicle 10. When attached to the vehicle body 11, the coupling device 15 connects the work machine 19 to the vehicle body 11 and has a mechanism for raising and lowering the work machine 19, and a mechanism for operating the work machine 19. Figure 13 is a perspective view of the coupling device 15 as seen from the work vehicle 10 side. The coupling device 15 has a first mounting part 71 that is attached to the work vehicle 10, a second mounting part 72 for attaching the work machine 19, a motor 74 for the work machine 19, and a lifting mechanism 70. Furthermore, the coupling device 15 of this embodiment has an inverter 75 that outputs power to the motor 74. The first mounting part 71, the second mounting part 72, and the lifting mechanism 70 constitute the mounting unit 18 of the coupling device 15. The motor 74 that outputs power to the work machine 19 is attached to the mounting unit 18. The lifting mechanism 70 raises and lowers the second mounting section 72 and the motor 74 relative to the first mounting section 71. The mounting unit 18 is a part for attaching the work machine 19 to the work vehicle 10 (vehicle body 11) so that it can be raised and lowered, and the lifting mechanism 70 makes it possible to raise and lower the motor 74 together with the work machine 19.

[0123] The first mounting portion 71 is attached to a fixing portion 41 of the central frame 20 of the vehicle body 11 (see Figure 11). The first mounting portion 71 is detachably attached to a mounting block 43 (see Figure 12) of the fixing portion 41. The mounting block 43 has an upper engaging portion 432 at its upper part and a lower engaging portion 433 at its lower part. In this embodiment, the upper engaging portion 432 is a recess that opens upward, and the lower engaging portion 433 is a recess that opens downward and backward.

[0124] As shown in Figure 13, the first mounting portion 71 has a mounting frame 77 that is long in the vertical direction. The mounting frame 77 has an upper fixing member 771 at its upper part and a lower fixing member 772 at its lower part. In this embodiment, the upper fixing member 771 is an axial member whose axis is in the left-right direction and is fixed to the upper part of the mounting frame 77, and the lower fixing member 772 is an axial member whose axis is in the left-right direction and is fixed to the lower part of the mounting frame 77.

[0125] The coupling device 15 is brought close to the mounting block 43 of the fixing part 41 from above, and after the upper fixing member 771 is fitted into the upper engaging part 432 from above, the lower fixing member 772 is fitted into the lower engaging part 433 from behind while the orientation of the coupling device 15 is changed. In this state, although not shown, a stopper pin built into the lower engaging part 433 pops out downward. When the lower fixing member 772 fitted into the recess of the lower engaging part 433 tries to move backward, the stopper pin contacts the lower fixing member 772 and restricts its movement. As a result, the coupling device 15 (mounting frame 77) is supported and connected to the fixing part 41 (mounting block 43).

[0126] When the stopper pin is moved upward (to a state where it is built into the lower engagement portion 433), the lower fixing member 772 becomes displaceable. This makes it possible to detach the mounting frame 77 of the coupling device 15 from the mounting block 43 of the fixing portion 41. With the above configuration, the coupling device 15 is connected to the fixing portion 41 and is also detachable from the fixing portion 41. In this embodiment, the mounting frame 77 of the coupling device 15 is connected to the fixing portion 41 at the upper and lower positions by the upper fixing member 771 and the lower fixing member 772, resulting in a strong connection.

[0127] Figure 14 is a perspective view of the coupling device 15 as seen from the implement side (rear side). The second mounting section 72 is a frame structure for mounting the implement 19. The second mounting section 72 is displaced vertically by the lifting mechanism 70. In this embodiment, the second mounting section 72 swings vertically relative to the first mounting section 71. The second mounting section 72 has a hitch frame 79 that facilitates the attachment and detachment of the implement 19. The hitch frame 79 has a common configuration with, for example, the hitch frame mounted on a conventional tractor. The hitch frame 79 makes it possible to attach conventional implements 19, and also makes it easy to attach and detach the implement 19.

[0128] The second mounting section 72 swings up and down by the lifting mechanism 70, thereby changing its vertical position and its orientation (angle of inclination) in the vertical direction. The motor 74 is mounted to the second mounting section 72 via a bracket 78, and the motor 74 and the second mounting section 72 are relatively unable to change their orientation. The motor 74 is supported by the bracket 78 from the left and right directions.

[0129] The motor 74 has a rotationally driven output shaft 741. The rear end of the output shaft 741 is located in front of the rear end of the second mounting portion 72. In other words, the output shaft 741 does not protrude rearward from the second mounting portion 72. The output shaft 741 is connected to the input shaft of the work implement 19. Since the work implement 19 does not have a motor, the motor 74 of the coupling device 15 outputs power to the work implement 19. The motor 74 may include a reduction gear if necessary. The vertical orientation of the motor 74 (output shaft 741) is changed to match the vertical position (orientation) of the second mounting portion 72 and is uniquely determined in accordance with the vertical position (orientation) of the second mounting portion 72. When the work implement 19 is attached to the second mounting portion 72, the input shaft of the work implement 19 is connected to the output shaft 741 of the motor 74 without the need for a universal joint, and this state is maintained. The output of the motor 74 is then supplied to the input shaft of the work implement 19.

[0130] The lifting mechanism 70 includes a link mechanism 80 and an actuator 81. The link mechanism 80 in this embodiment includes one upper link member 85 and two lower link members 86, 86. The upper link member 85 has its first end 851 pivotably attached to a first mounting portion 71, and its second end 852 pivotably attached to a second mounting portion 72. Each of the two lower link members 86, 86 has its first end 861 pivotably attached to a first mounting portion 71, and its second end 862 pivotably attached to a second mounting portion 72.

[0131] The actuator 81 has two hydraulic cylinders 811 located on the left and right sides. The hydraulic cylinders 811 operate by receiving hydraulic fluid supplied from a hydraulic unit 17 mounted on the vehicle body 11 (see Figure 2). In this embodiment, the actuator 81 further has two arms 812 that are pivotably mounted on the upper part of the first mounting portion 71, and two rods 813 that connect the arms 812 to the lower link member 86. The rods 813 are pivotably mounted at both ends to the arms 812 and the lower link member 86, respectively.

[0132] Both ends of the hydraulic cylinder 811 are pivotably attached to the first mounting portion 71 and the middle portion of the arm 812, respectively. When the hydraulic cylinder 811 extends, the rod 813 lifts the lower link member 86, causing the second mounting portion 72 to swing upward. When the hydraulic cylinder 811 shortens, the lower link member 86 is displaced downward, causing the second mounting portion 72 to swing downward. With this link mechanism 80, the lifting mechanism 70 is configured compactly.

[0133] As described above, the actuator 81 having a hydraulic cylinder 811 drives the lower link member 86 up and down relative to the first mounting portion 71, thereby raising and lowering the second mounting portion 72. Since the motor 74 is integrated with the second mounting portion 72, the lifting mechanism 70 causes the second mounting portion 72 and the motor 74 to move up and down relative to the first mounting portion 71.

[0134] The two lower link members 86, 86 are located below the upper link member 85 and on both the left and right sides of the upper link member 85 in a plan view. The motor 74 is located below the upper link member 85 and between the two lower link members 86, 86. In other words, the motor 74 is located in the space formed below the upper link member 85 and between the two lower link members 86, 86. The coupling device 15 is equipped with the motor 74, but the arrangement of the motor 74 as described above allows for efficient use of space, making it possible to configure the coupling device 15 compactly.

[0135] The link mechanism 80 and actuator 81 of the lifting mechanism 70 may have configurations other than those shown. The actuator 81 only needs to drive the lower link member 86 or the upper link member 85 up and down relative to the first mounting portion 71. The lifting mechanism 70 may have a configuration other than having a link mechanism 80, and if it does have a link mechanism 80, the shape and number of link members included therein can be changed.

[0136] As described above, the coupling device 15 of this embodiment has an inverter 75 that outputs power to the motor 74. In the coupling device 15, the motor 74 is located in the center in the left-right direction, and the inverter 75 is located on the left or right side in the left-right direction. In this embodiment, the inverter 75 is located to the right of the motor 74 in the coupling device 15. This arrangement makes the coupling device 15 more compact in the front-rear direction.

[0137] The motor 74 is attached to the second mounting section 72, while the inverter 75 is attached to the first mounting section 71. The motor 74 moves up and down together with the second mounting section 72, whereas the inverter 75 is attached to the first mounting section 71, which is fixed to the work vehicle 10 (fixed section 41), and does not move up or down. Therefore, the load on the lifting mechanism 70 (hydraulic cylinder 811) is small.

[0138] The motor 74 (see Figure 13) has a terminal box 743 on its front side, which is the side of the first mounting portion 71. The electrical wiring 742 connected to the terminal block of the motor 74 extends from the terminal box 743 to the inverter 75 side. The inverter 75 has electrical wiring 751 connected to the motor 74 side. The electrical wiring 742 of the motor 74 and the electrical wiring 751 of the inverter 75 are electrically connected via a coupling 76. The coupling 76 connects the electrical wiring 742 connected to the motor 74 and the electrical wiring 751 connected to the inverter 75. The coupling 76 is attached to the upper link member 85. Because the coupling 76 is attached to the upper link member 85 which is exposed to the outside, maintenance such as replacement of the inverter 75 or motor 74 is made easier.

[0139] The coupling device 15 has a coupling 88 (coupling device side coupling 88). The coupling 88 is located on the first mounting portion 71 side of the coupling device 15. In this embodiment, the coupling 88 is provided on the mounting frame 77 of the first mounting portion 71. When the coupling device 15 is attached to the fixing portion 41 (see Figure 12) of the vehicle body 11, the coupling 88 is connected to the vehicle side coupling 44.

[0140] As described above, the vehicle-side coupling 44 is connected to the fluid piping 36 and the electrical wiring 37. The coupling device 15 has a pipe 89 that is connected to the coupling 88 and the fluid piping 36, and a wire 90 that is connected to the coupling 88 and the electrical wiring 37. When the coupling device 15 is attached to the fixing part 41 of the vehicle body 11, the coupling device-side coupling 88 and the vehicle-side coupling 44 are connected. Then, the hydraulic fluid supplied from the hydraulic unit 17 of the vehicle body 11 is supplied to the hydraulic cylinder 811 through the vehicle-side coupling 44, the coupling device-side coupling 88, and the pipe 89.

[0141] If the work machine 19 is, for example, a spraying device that sprays a liquid substance (chemicals or water), then the piping 89 connected to the coupling 88 includes liquid piping. As described above, liquid piping 362 extending from a tank (not shown) for storing the spraying substance is connected to the vehicle-side coupling 44. The spraying substance in the liquid piping 362 is supplied to the work machine 19 from the vehicle-side coupling 44 and the coupling device-side coupling 88 through the relay piping of the coupling device 15.

[0142] Furthermore, when the coupling device 15 is attached to the fixing part 41 of the vehicle body 11, the coupling 88 and the vehicle-side coupling 44 are connected. As described above, a power wire 371 for supplying power from the battery 16 (first battery 16A) is connected to the vehicle-side coupling 44. Power from the battery 16 is supplied to the inverter 75 and motor 74, etc., through the power wire 371, the vehicle-side coupling 44, the coupling device-side coupling 88, and the wiring 90 of the coupling device 15.

[0143] The mounting frame 77 of the first mounting section 71 has an opening 87 (see Figure 13). The opening 87 is a hole that penetrates in the front-rear direction from the work vehicle 10 side to the work machine 19 side. The piping 89 and wiring 90 pass through this opening 87. The mounting frame 77 is large vertically, but the opening 87 allows for piping and wiring between the work vehicle 10 and the coupling device 15.

[0144] Thus, the coupling 88 of the coupling device 15 serves as a connector for connecting the liquid piping 36 (hydraulic piping 361, liquid piping 362 for the work machine 19) and electrical wiring 37 provided on the vehicle body 11 side. When attaching the coupling device 15 to the work vehicle 10, the coupling 88 facilitates the connection of necessary connections between the coupling device 15 and the work vehicle 10, such as the hydraulic piping 361 for the lifting mechanism 70, the liquid piping 362 for the work machine 19, the electrical wiring for the motor 74 of the coupling device 15, or the electrical wiring for the work machine 19.

[0145] As described above, the coupling device 15 of this embodiment is a device for coupling a work machine 19 to a work vehicle 10. The coupling device 15 has a mounting unit 18 that attaches the work machine 19 to the work vehicle 10 (vehicle body 11) so that it can be raised and lowered, and a motor 74 that outputs power to the work machine 19. The motor 74 is attached to the mounting unit 18. The mounting unit 18 raises and lowers the motor 74 together with the work machine 19. In this embodiment, the mounting unit 18 is composed of a first mounting part 71, a second mounting part 72, and a lifting mechanism 70 that raises and lowers the second mounting part 72 and the motor 74 relative to the first mounting part 71.

[0146] As described above, the coupling device 15 for connecting the work machine 19 to the vehicle body 11 has a motor 74, and the output of the motor 74 is used to power the work machine 19. Therefore, the work vehicle 10 and the work machine 19 do not need a motor for work power. Since the work machine 19 does not require a motor to operate itself, it is possible to connect a conventional work machine 19 that does not have a motor to the work vehicle 10. Moreover, the motor 74 is attached to a mounting unit 18 of the coupling device 15, and the motor 74 moves up and down together with the work machine 19 by the mounting unit 18. Therefore, the work machine 19 and the motor 74 are directly connected without the need for a power transmission mechanism with a complex configuration such as a universal joint, and the connection structure is simplified.

[0147] The mounting unit 18 is detachable from the fixing part 41 of the work vehicle 10. In other words, the coupling device 15 is detachable from the work vehicle 10 (vehicle body 11). When the work vehicle 10 requires a work implement 19, it can connect the work implement 19 via the coupling device 15. Conversely, when the work vehicle 10 does not require the work implement 19, the work implement 19 can be detached from the coupling device 15, and the coupling device 15 can also be detached from the work vehicle 10. The work implement 19 and the coupling device 15 are detachable depending on the work, and the coupling device 15 makes it possible to increase the versatility of the work vehicle 10. By detaching the coupling device 15 from the work vehicle 10, maintenance of the work vehicle 10 becomes easier.

[0148] The work vehicle 10 can have the work machine 19 perform agricultural work or other tasks while it is in motion. The work machine 19 and the coupling device 15 can be attached and detached depending on the application, resulting in a highly versatile work vehicle 10. Depending on the type of work machine 19 to be coupled, the work performed by the work machine 19, or the state of that work, the posture of the mounting unit 18 is changed by the lifting mechanism 70. In other words, the lifting mechanism 70 changes the posture of the second mounting section 72 and the posture of the work machine 19 attached to the second mounting section 72, and also makes it possible to change the output direction of the motor 74 (the axial direction of the output shaft 741).

[0149] As described above, the coupling device 15 has an inverter 75 that outputs power to the motor 74. The rotation of the motor 74 is controlled by the inverter 75. For example, if the specifications of the motor 74, such as the output, are to be changed according to the work machine 19, if the inverter 75 is mounted inside the work vehicle 10, that work would be relatively difficult. In contrast, in this embodiment, the inverter 75 is mounted on the exposed coupling device 15. Therefore, the work of changing the specifications as described above becomes easy.

[0150] [Cover 95 of Fixing Part 41] Figure 15 is an explanatory diagram of the rear of the work vehicle 10. As described above, the vehicle body 11 has a fixing part 41 to which a coupling device 15, which is another piece of equipment, is attached detachably. The fixing part 41 has a vehicle-side coupling 44 for connecting the liquid piping 36 and electrical wiring 37 provided on the vehicle body 11. The vehicle-side coupling 44 has a connection port for connecting the coupling 88 (see Figure 13) on the coupling device 15 side.

[0151] The fixed part 41 includes a cover 95 and a cover actuator 96. The cover actuator 96 switches the cover 95 between a first state and a second state. Figure 16 shows the case where the cover 95 is in the first state, and Figure 15 shows the case where the cover 95 is in the second state. In the first state, the cover 95 covers the connection port side of the vehicle-side coupling 44 of the fixed part 41, and in the second state, it opens the connection port side of the vehicle-side coupling 44 of the fixed part 41. The operation of the cover actuator 96 is controlled by a control device 14 (see Figure 6) of the work vehicle 10.

[0152] The cover 95 shown in Figures 15 and 16 has a shutter curtain structure with multiple horizontally elongated strip-shaped slats 951. The cover actuator 96 has a motor for winding up such a cover 95. Although not shown, the fixing part 41 may have rails that guide the opening and closing operation of the cover 95 (multiple slats 951). The fixing part 41 has a storage part (storage box) 97 for storing the cover 95 in the second state (see Figure 15). The cover 95 in the second state is stored in the storage part 97. The cover actuator 96 with a motor is housed in the storage part 97.

[0153] When the coupling device 15 is attached to the fixed part 41, the cover actuator 96 sets the cover 95 to the second state, and the rear of the fixed part 41 is left open. When the coupling device 15 is not attached to the fixed part 41, the cover actuator 96 sets the cover 95 to the first state, and the fixed part 41 is covered by the cover 95. Having the cover 95 in the first state provides a good appearance and prevents foreign matter from adhering to the vehicle-side coupling 44.

[0154] The cover 95 may be configured to cover only the vehicle-side coupling 44, but in this embodiment, it covers the entire fixing portion 41. As described above, the fixing portion 41 has an upper engaging portion 432 as a coupling portion for mechanically connecting the coupling device 15. The upper engaging portion 432 is a recess that opens upward and is provided in the mounting block 43 of the fixing portion 41. As shown in Figure 16, the cover 95 covers the vehicle-side coupling 44 and the upper engaging portion 432, which is the coupling portion. The cover 95 may also be configured to cover the lower engaging portion 433, which is a coupling portion for mechanically connecting the coupling device 15.

[0155] Figures 17 and 18 are explanatory diagrams showing modified examples of the cover 95. The cover 95 shown in Figures 17 and 18 is plate-shaped. Figure 17 shows the cover 95 in the first state, covering the connection port side of the vehicle-side coupling 44 of the fixing part 41. Figure 18 shows the cover 95 in a state between the first state and the second state. The cover actuator 96 performs the operation of pulling the cover 95 into the storage part (storage box) 97 or sending it out from the storage part 97. The cover actuator 96 is configured, for example, with a retractable cylinder.

[0156] The opening and closing of the cover 95, that is, the operation of the cover actuator 96, will now be described. The cover actuator 96 starts opening and closing the cover 95 when predetermined conditions are met. The operation of the cover actuator 96 is controlled by the control device 14, and the opening and closing of the cover 95 is performed automatically. The predetermined conditions are conditions related to the state or operation of the vehicle body 11, conditions related to the positional relationship between the vehicle body 11 and the coupling device 15, or conditions related to the identification of the coupling device 15. Each of these cases will be described below.

[0157] When the coupling device 15 is not attached to the fixing portion 41 of the vehicle body 11, and the fixing portion 41 and the coupling device 15 are in a position that is relatively close to each other, and the vehicle body 11 starts moving using the running gear 12 (operation of the vehicle body 11), and approaches the coupling device 15 (the aforementioned positional relationship), the cover actuator 96 starts operating and opens the cover 95. Conversely, when the coupling device 15 is attached to the fixing portion 41, and the coupling device 15 is detached from the fixing portion 41, and the vehicle body 11 starts moving using the running gear 12 (operation of the vehicle body 11), and moves away from the coupling device 15 (the aforementioned positional relationship), the cover actuator 96 starts operating and closes the cover 95.

[0158] Thus, when the coupling device 15 is not attached to the fixed part 41, and the relative positions of the vehicle body 11 and the coupling device 15 change, the cover actuator 96 operates to open and close the cover 95. When the conditions related to the operation of the vehicle body 11 and the conditions related to the positional relationship between the vehicle body 11 and the coupling device 15 are met, the opening and closing of the cover 95 is automatically started. The vehicle body 11 has a detection device 92 such as a camera (see Figure 1), and the positional relationship is detected by the detection device 92.

[0159] Let's describe another example of the operation of the cover actuator 96. Various operation programs are stored in the work vehicle 10 (control device 14), and among these operation programs is an operation program that automatically connects and disconnects the coupling device 15. When the coupling device 15 is not attached to the fixed part 41, and the operation proceeds to the operation step for the vehicle body 11 to connect with the coupling device 15 according to the operation program, the cover actuator 96 starts to operate and opens the cover 95. Conversely, when the coupling device 15 is attached to the fixed part 41, and the operation proceeds to the operation step for disconnecting the fixed part 41 and the coupling device 15 according to the operation program, and then the operation proceeds to the operation step for moving the vehicle body 11 away from the coupling device 15, the cover actuator 96 starts to operate and closes the cover 95.

[0160] Thus, when the vehicle body 11 proceeds to an operation step for connecting with the coupling device 15, or an operation step after disconnecting from the coupling device 15, according to the set operation program, the cover actuator 96 starts operating. When the conditions related to the state of the vehicle body 11 based on the operation program are met, the opening and closing of the cover 95 starts automatically.

[0161] Let's describe another example of the operation of the cover actuator 96. The vehicle body 11 has a detection device 92 (see Figure 1), such as a camera. When the coupling device 15 is not attached to the fixing part 41, and the detection device 92 detects the coupling device 15 or identification information such as a mark attached to the coupling device 15, the cover actuator 96 starts to operate, and the cover 95 opens. When the detection device 92 can no longer detect the coupling device 15 or the identification information attached to the coupling device 15, the cover actuator 96 starts to operate, and the cover 95 closes.

[0162] Thus, when the detection device 92 detects the coupling device 15 or identification information of the coupling device 15, the cover actuator 96 starts operating. When the conditions for identifying the coupling device 15 are met, the opening and closing of the cover 95 starts automatically.

[0163] As described above, the fixed section 41 of the work vehicle 10 in this embodiment includes a vehicle-side coupling 44, a cover 95, and a cover actuator 96 that switches the cover 95 between a first state and a second state. In the first state, the cover 95 covers the connection port side of the vehicle-side coupling 44, and in the second state, it opens the connection port side of the vehicle-side coupling 44. Even when the work vehicle 10 is used in an outdoor environment with a lot of foreign matter such as soil dust and dirt, such as a farm, if the work machine 19 is not connected to the fixed section 41, the fixed section 41 having the vehicle-side coupling 44 is protected by the cover 95, making it possible to prevent malfunctions.

[0164] [Other] In the above embodiment, the coupling device 15 is attached to the rear of the vehicle body 11. The mounting position of the coupling device 15 on the vehicle body 11 may be other. For example, the coupling device 15 may be attached to the front of the vehicle body 11, in which case the work equipment 19 is also located in front of the vehicle body 11. Alternatively, the coupling device 15 may be attached to the right or left of the vehicle body 11, in which case the work equipment 19 is also located to the right or left of the vehicle body 11. Alternatively, the coupling device 15 may be attached to any other position on the vehicle body 11.

[0165] Furthermore, the vehicle body 11 may have multiple fixing parts 41 for attaching the coupling device 15 at various locations. For example, the vehicle body 11 may have fixing parts 41 at each of its four positions: front, rear, left, and right. In this case, for example, the coupling device 15 may be attached to one or both sides of the vehicle body 11 in the front-rear direction, and one or both sides in the left-right direction. Multiple work machines 19, each attached to one or both sides of the vehicle body 11 in the front-rear direction, and one or both sides in the left-right direction, may then perform their respective tasks.

[0166] In the above embodiment, another device attached to the fixing part 41 is a coupling device 15. The fixing part 41 having the cover 95 and the configuration related to the cover 95 as described above may be configured to attach a different device than the coupling device 15. For example, the work machine 19 may be directly attached to the fixing part 41, and the fixing part 41 may have the cover 95 and the configuration related to the cover 95. In other words, another device attached to the fixing part 41 is the work machine 19, or the coupling device 15 for attaching the work machine 19.

[0167] <Regarding the Third Invention> [Overall Configuration of the Work Vehicle According to the Third Invention] Figures 22 and 23 are perspective views showing one embodiment of the work vehicle 10 according to the third invention. This work vehicle 10 has an exterior member 9, and Figure 23 shows the state with the exterior member 9 removed. The exterior member 9 is attached to the frames 20 and 21 of the work vehicle 10. The exterior member 9 protects the various devices of the work vehicle 10 and enhances its design. Figures 24, 25, and 26 are a plan view, left side view, and right side view of the work vehicle 10 shown in Figure 23. The configuration diagram of the work vehicle 10 according to the third invention is the same as the configuration diagram shown in Figure 6.

[0168] The work vehicle 10 has a running gear 12 and travels on road surfaces such as fields and roads. In the case of the work vehicle 10 of this embodiment, the direction pointed to by arrow X1 in each figure is the basic direction of travel and is defined as "forward". In each figure, the direction pointed to by arrow X2 is the opposite direction of the basic direction of travel and is defined as "rear". In each figure, the direction pointed to by arrow Y1 is defined as "left", the direction pointed to by arrow Y2 is defined as "right", the direction pointed to by arrow Z1 is defined as "up", and the direction pointed to by arrow Z2 is defined as "down".

[0169] The work vehicle 10 is capable of moving straight in both forward and backward directions, as well as turning left and turning right, thanks to its running gear 12. The running gear 12 is located at four points on the front, rear, left, and right of the vehicle body 11, and each running gear 12 has wheels 25. The work vehicle 10 has a hydraulic motor, which allows the direction of the wheels 25 (the direction in which the wheels 25 roll) to be changed within a 360-degree range. Therefore, the work vehicle 10, which can move forward and backward, can move straight in all 360 degrees. Note that an electric motor may be used instead of the hydraulic motor. Alternatively, the work vehicle 10 may be capable of changing the direction of the wheels 25 from the basic direction of travel within a range of 0 to 90 degrees, for example, by a hydraulic cylinder. When the direction of the wheels 25 changes by 90 degrees from the basic direction of travel, their rolling direction becomes either left or right. The work vehicle 10 can also move straight in either left or right. Furthermore, the work vehicle 10 may be able to change the direction of its wheels 25 within a range of 0 to -90 degrees using the hydraulic cylinder, from its initial state in the basic direction of travel. Since the direction of the wheels 25 can be changed within a range of 0 to 90 degrees and within a range of 0 to -90 degrees from its initial state in the basic direction of travel, and since it is possible to move forward and backward, the work vehicle 10 can move in a straight line in all 360 degrees.

[0170] The work vehicle 10 connects to the work machine 19 via a coupling device 15. Figures 22, 23, 25, and 26 show the work machine 19 as a dashed line. The work machine 19 has a configuration and functions for performing various tasks. The tasks performed by the work machine 19 include, but are not limited to, tasks related to agriculture, industrial tasks (civil engineering, construction, etc.), and transportation tasks. The work vehicle 10 travels together with the work machine 19, while the work machine 19 performs its tasks.

[0171] In this embodiment, the work performed by the implement 19 is agricultural work. The implement 19 includes, for example, a spraying device for applying fertilizer or chemicals to a field, a seeding device for sowing seeds, a tilling device for cultivating the soil, a tilling device for tilling the soil, a weeding device for weeding, a soil mounding device for mounding soil, and so on. The implement 19 is replaced according to the required work.

[0172] In the case of the work vehicle 10 shown in Figure 22, the basic direction of travel is forward. The work vehicle 10 has a fixed part 41 at a position opposite to its direction of travel (forward), in the rear direction. A coupling device 15, which is another piece of equipment, is attached to this fixed part 41. The fixed part 41 can attach the other piece of equipment (coupling device 15) to the vehicle body 11 and can output power energy to the other piece of equipment (coupling device 15). This power energy includes at least one of electrical energy such as electricity, physical energy such as rotational force, and hydraulic energy. The configuration of the fixed part 41 will be described later.

[0173] In the case of the work vehicle 10 shown in Figures 22 to 26, the fixing part 41 is provided not only at the rear position of the vehicle body 11, but also at the front position, and furthermore, at both sides in the left-right direction of the vehicle body 11. In other words, the fixing part 41 is provided at four locations on the front, rear, left, and right sides of the vehicle body 11.

[0174] As described above, the vehicle body 11 is capable of traveling in four directions: forward, backward, left, and right, by the four running gears 12. However, the vehicle body 11 only needs to be capable of traveling in at least three directions. The fixing part 41 is provided at each of the positions corresponding to the at least three directions of travel. The at least three directions of travel are at least three of the forward, backward, left, and right directions. The "positions corresponding to the directions of travel" may include positions on the side of the direction of travel or positions on the opposite side of the direction of travel. For example, if the direction of travel of the vehicle body 11 is forward, the "position on the side of the direction of travel" is the front position, and if the direction of travel of the vehicle body 11 is right, the "position on the side of the direction of travel" is the right position. Furthermore, if the direction of travel of the vehicle body 11 is forward, the "position on the opposite side of the direction of travel" is the rear position, and if the direction of travel of the vehicle body 11 is right, the "position on the opposite side of the direction of travel" is the left position. Moreover, as described above, the work vehicle 10 is capable of moving straight in all 360 degrees. Therefore, for example, the work vehicle 10 can travel in an oblique direction, tilted to either the left or right relative to the front-rear direction. Thus, the fixing part 41 may be provided on the vehicle body 11 at a front position (or rear position) in the left oblique direction, or at a front position (or rear position) in the right oblique direction.

[0175] Further explanation will be given regarding the position of the fixing portion 41 on the vehicle body 11. The work vehicle 10 has a running device 12, which enables the vehicle body 11 to travel in three different directions: first, second, and third. The fixing portion 41 only needs to be provided at least on the first direction side, the second direction side, and the third direction side of the vehicle body 11. In this embodiment, the first direction is the forward direction, and the second direction is the rear direction, which is opposite to the forward direction. The third direction is one of the left and right directions that are perpendicular to the front and rear directions. In other words, the fixing portion 41 only needs to be provided at least at the position in the first direction (forward direction), the second direction (rear direction), and one of the left and right directions that are third directions. The third direction may be perpendicular to the first and second directions (front and rear directions), but it may also be inclined at an angle greater than 0 degrees and less than 90 degrees with respect to the first and second directions (front and rear directions).

[0176] The number of fixing parts 41 provided at each position of the vehicle body 11, that is, the number of other devices (coupling devices 15) attached to each position of the vehicle body 11, is at least one, but may be multiple. For example, two fixing parts 41 may be provided at the front of the vehicle body 11, and two other devices may be attached to the front of those. In other words, at least one fixing part 41 is provided at a position on the side of the direction of travel, at least one is provided at a position opposite to the direction of travel, and at least one is provided at a position different from the position corresponding to the direction of travel. An example of a position different from the position corresponding to the direction of travel is, for example, the upper or lower position of the vehicle body 11.

[0177] As will be explained later (see Figure 21), as a modified example of the work vehicle 10, the fixing part 41 may be provided not only at the aforementioned positions on the vehicle body 11, but also at the upper and lower positions on the vehicle body 11.

[0178] Comparing the work apparatus 10 according to the third invention with the work apparatus 10 according to the first, second, and fourth inventions, as described above, the number and arrangement of the fixing parts 41 are different, but the other configurations are the same. The same components are denoted by the same reference numerals, and explanations of the same components are omitted.

[0179] The configuration of the fixing parts 41 at positions other than the rear position of the vehicle body 11 (for example, the front position, the left and right positions) is the same as the configuration of the fixing part 41 at the rear position. The fixing parts 41 at the left and right positions are provided on the side frames 21L and 21R. Therefore, "central frame 20" in the description should be read as "side frames 21L and 21R". In addition, the fixing parts 41 at the left and right positions may be provided on both of the pair of side frames 21L and 21R, or on one of the pair of side frames 21L and 21R.

[0180] In the work device 10 according to the third invention, the fixing part 41 also has a cover 95 and a cover actuator 96 (see Figures 15 to 19). Not only the fixing part 41 at the rear position of the vehicle body 11, but also the fixing parts 41 at other positions have a cover 95, a cover actuator 96, and a storage part 97.

[0181] [Regarding the arrangement of the coupling device 15 and the work machine 19] Figure 19 is a schematic diagram showing another example of the work vehicle 10. The work vehicle 10 shown in Figure 19 has the same configuration as the work vehicle 10 shown in Figure 22, etc., but the arrangement of other equipment attached to the fixed part 41 is different. Also, in the above embodiment (see, for example, Figure 22), the other equipment attached to the fixed part 41 is the coupling device 15. The fixed part 41 may be configured to attach equipment other than the coupling device 15. For example, the work machine 19 may be directly attached to the fixed part 41 as another piece of equipment. In other words, the other equipment attached to the fixed part 41 is the work machine 19, or the coupling device 15 for attaching the work machine 19.

[0182] The work vehicle 10 shown in Figure 19 has different equipment connected to the front and rear fixing parts 41. Specifically, a first coupling device 15 is attached to the front fixing part 41 of the vehicle body 11, and a second coupling device 15 is attached to the rear fixing part 41 of the vehicle body 11. A first work machine 19 is attached to the first coupling device 15, and a second work machine 19 is attached to the second coupling device 15.

[0183] Figure 20 is a schematic diagram showing yet another example of the work vehicle 10. The work vehicle 10 shown in Figure 20 has the same configuration as the work vehicle 10 shown in Figures 22 and 19, but the arrangement of other equipment attached to the fixed part 41 is different. The work vehicle 10 shown in Figure 20, like the work vehicle 10 shown in Figure 22, has a first coupling device 15 attached to the rear fixed part 41, and second coupling devices 15 attached to the left and right fixed parts 41. A first work machine 19 is attached to the first coupling device 15, and a second work machine 19 is attached to the second coupling device 15. Note that the fixed part 41 may be provided on one or both of the left and right side frames 21L and 21R. When the fixed part 41 is provided on both the left and right side frames 21L and 21R, the coupling device 15 may be attached to both of the left and right fixed parts 41, or the coupling device 15 may be attached to either the left or right fixed part 41.

[0184] As described above, the fixing parts 41 are provided at the front, rear, left, and right positions of the vehicle body 11, and the coupling device 15 can be attached to at least one of the fixing parts 41 in the front, rear, left, or right positions. When the coupling device 15 and the work machine 19 are attached to the fixing part 41 at the front of the vehicle body 11, the work vehicle 10 can, for example, push the work machine 19 while traveling forward, and the work machine 19 can perform work in front of the vehicle body 11.

[0185] When the coupling device 15 and the work implement 19 are attached to the fixing part 41 at the rear of the vehicle body 11, the work vehicle 10 can, for example, tow the work implement 19 while traveling forward, and the work implement 19 can perform work, etc., at the rear of the vehicle body 11. When the coupling device 15 and the work implement 19 are attached to the fixing part 41 at the left or right position of the vehicle body 11, the work vehicle 10 can, for example, travel forward with the left or right work implement 19 accompanying it, and the work implement 19 can perform work, etc., at the left or right position of the work vehicle 10.

[0186] Figure 21 is a schematic diagram showing yet another example of the work vehicle 10. The vehicle body 11 may have additional fixing parts 41 at either the upper position or the lower position, or both. Additional equipment (coupling device 15, work machine 19) can also be attached to the fixing parts 41 provided at either the upper position or the lower position, or both, of the vehicle body 11.

[0187] In the case of the work vehicle 10 shown in Figure 21, a fixing part 41 is provided at the upper position of the vehicle body 11. A coupling device 15 is connected to this fixing part 41, and a work machine 19 is attached to the coupling device 15. Note that the coupling device 15 at the upper position shown in Figure 21 has a different form from the coupling device 15 at the rear position shown in Figure 22, etc. The coupling device 15 has a coupling part 151 that straddles a part of the vehicle body 11 from the upper fixing part 41, and the work machine 19 is attached to this coupling part 151. In the case of the work vehicle 10 shown in Figure 21, the work machine 19 is located at the rear of the vehicle body 11, but it may also be located at the front, or at either the left or right side, or both.

[0188] The fixing parts 41 are provided at the front, rear, left, right, top, and bottom positions, and the coupling device 15 and the work machine 19 can be attached to at least one of the fixing parts 41 in the front, rear, left, right, top, or bottom positions. If the fixing part 41 is provided at an upper position on the vehicle body 11, another device to be attached to that fixing part 41 may be mounted on top of the vehicle body 11, although this is not shown. In this case, the work machine 19 will perform its work on top of the vehicle body 11. If the fixing part 41 is provided at a lower position on the vehicle body 11, the fixing part 41 may be provided at a lower position on the central frame 20, or at a lower position on one or both of the left and right side frames 21L, 21R.

[0189] Each of the above-described forms (including the above-described alternative examples) of the work vehicle 10 is configured to output power energy to each of the multiple other devices attached to the multiple fixed parts 41. For example, power is supplied from the battery 16 (central first battery 16A) to the front and rear coupling devices 15 and the front and rear work machines 19, and at the same time, power is supplied from the battery 16 (side second batteries 16L, 16R) to one or both of the left and right coupling devices 15 and the left and right work machines 19. In addition to power, hydraulic pressure from the hydraulic unit 17 may also be supplied from each fixed part 41. With this configuration, one work vehicle 10 can be fitted with multiple other devices, and these multiple devices can perform work simultaneously, resulting in high work efficiency.

[0190] As explained in Figure 12, the fixed section 41 has a vehicle-side coupling 44 for connecting one or both of the piping and wiring. This vehicle-side coupling 44 is provided on each fixed section 41 of other work vehicles 10 (including the other examples described above), in addition to the fixed sections 41 of the forms shown in Figures 22 and 23, etc.

[0191] Each of the above-described forms of the work vehicle 10, including Figure 22, has a coupling device 15 as another device attached to the fixed part 41. As described above, the coupling device 15 is attached to the fixed part 41 in a detachable manner and allows the work equipment 19 to be attached. The coupling device 15 (see Figure 14) has a lifting mechanism 70 for raising and lowering the work equipment 19, a motor 74 that outputs power to the work equipment 19, and an inverter 75 that outputs power to the motor 74. Therefore, although the vehicle body 11 can have multiple work equipment 19 attached to multiple fixed parts 41 via the coupling device 15, the vehicle body 11 does not require a motor and inverter to operate the work equipment 19, and furthermore, it does not require a lifting mechanism for raising and lowering the work equipment 19. Thus, the vehicle body 11 can be simplified.

[0192] Furthermore, the coupling device 15, which is another device attached to the fixed part 41, has a hydraulic cylinder 73 of a lifting mechanism 70, which is a drive unit for operating the coupling device 15, and a motor 74, which is a drive unit for operating another device, the work machine 19, which is attached via the coupling device 15. The vehicle body 11 has a hydraulic unit 17 and a battery 16 as power sources to power these hydraulic cylinders 73 and motors 74. Thus, the vehicle body 11 has a hydraulic unit 17 and a battery 16 as power sources, but does not require a drive unit such as a hydraulic cylinder 73 and a motor 74 for operating the coupling device 15. In this embodiment, the work vehicle 10 can be fitted with multiple coupling devices 15, but even in this case, the work vehicle 10 does not require a drive unit (hydraulic cylinder 73 and motor 74) for each of the multiple coupling devices 15. Therefore, the vehicle body 11 can be simplified.

[0193] [Note] The embodiments of the first to fourth inventions described above are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims rather than the embodiments, and includes all modifications within the scope of equivalence to the configurations described in the claims.

[0194] 10 Work vehicle 11 Vehicle body 12 Running gear 13 Displacement actuator 15 Coupling device (another device) 16 Battery (power source) 17 Hydraulic unit (power source) 18 Mounting unit 19 Work machine 20 Central frame 21L, 21R Side frames 25 Wheels 35 Operating equipment (valve unit) 41 Fixing part 42 Frame 43 Mounting block 44 Vehicle side coupling 70 Lifting mechanism 71 First mounting part 72 Second mounting part 73 Hydraulic cylinder (drive unit) 74 Motor (drive unit) 75 Inverter 76 Joint 77 Mounting frame 78 Bracket 79 Hitch frame 80 Link mechanism 81 Actuator 85 Upper link member 86 Lower link member 87 Opening 88 Coupling (coupling device side coupling) 92 Detection device 95 Cover 96 Actuator for cover 97 Storage section 111 Upper part 201 Lower part 205 Case 421 Opening 432 Upper engaging part (connecting part) 433 Lower engaging part (connecting part) 771 Upper fixing member 772 Lower fixing member 851 First end 852 Second end 861 First end 862 Second end P1 Mounting position P2 Mounting position

Claims

1. A work vehicle comprising: a vehicle body; a running device for moving the vehicle body; and a coupling device for connecting a work machine to the vehicle body, wherein the coupling device comprises: a mounting unit for attaching the work machine to the vehicle body so as to be able to move up and down; and a motor for outputting power to the work machine, wherein the motor is attached to the mounting unit; and the mounting unit raises and lowers the motor together with the work machine.

2. The work vehicle according to claim 1, wherein the mounting unit is detachable from the vehicle body.

3. The work vehicle according to claim 1 or 2, wherein the vehicle body comprises a central frame and a pair of side frames located on both sides of the central frame and displaceable relative to the central frame, and the running gear is attached to each of the pair of side frames and has displacement actuators that allow the central frame and the side frames to be displaced relative to each other in at least one of the left-right and up-down directions.

4. The work vehicle according to any one of claims 1 to 3, wherein the vehicle body comprises a central frame having a battery and a case for housing the battery, and a pair of side frames located on both sides of the central frame and to which the running gear is attached, and the case is displaceable in the front-rear direction and housed in the central frame.

5. A coupling device for connecting a work machine to a work vehicle, comprising: a mounting unit for attaching the work machine to the work vehicle so as to be able to move up and down; and a motor for outputting power to the work machine, wherein the motor is attached to the mounting unit, and the mounting unit moves the motor up and down together with the work machine.

6. The coupling device according to claim 5, wherein the mounting unit is detachable from the work vehicle.

7. The coupling device according to claim 5 or 6, wherein the mounting unit comprises a first mounting portion to be attached to the work vehicle, a second mounting portion to which the work machine is attached, and a lifting mechanism for raising and lowering the second mounting portion and the motor relative to the first mounting portion.

8. The coupling device according to claim 7, wherein the lifting mechanism comprises a link mechanism and an actuator, the link mechanism comprises an upper link member and a lower link member, the first end of which is attached to the first mounting portion and the second end of which is attached to the second mounting portion, and the actuator drives the lower link member or the upper link member to move up and down relative to the first mounting portion.

9. The coupling device according to any one of claims 5 to 8, further comprising an inverter that outputs power to the motor.

10. The coupling device according to claim 7, comprising an inverter that outputs power to the motor, the lifting mechanism comprising a link mechanism and an actuator, the link mechanism comprising an upper link member and a lower link member, the first end of which is attached to the first mounting portion and the second end of which is attached to the second mounting portion, the actuator drives the lower link member or the upper link member to move up and down relative to the first mounting portion, and a coupling connecting electrical wiring connected to the motor and electrical wiring connected to the inverter is attached to the upper link member.

11. The coupling device according to claim 8 or 10, wherein the link mechanism comprises an upper link member and two lower link members located below the upper link member and on both sides of the upper link member in a plan view, and the motor is located below the upper link member and between the two lower link members.

12. The coupling device according to claim 9 or claim 10, wherein, when the direction of travel of the work vehicle is defined as the front in the front-rear direction, and the horizontal direction perpendicular to the front-rear direction is defined as the left-right direction, the motor is located in the center in the left-right direction, and the inverter is located on the left or right side in the left-right direction.

13. The coupling device according to claim 7, claim 8, or claim 10, comprising an inverter that outputs power to the motor, wherein the inverter is attached to the first mounting portion, and the motor is attached to the second mounting portion.

14. The coupling device according to claim 7, claim 8, claim 10, or claim 13, wherein it is located on the side of the first mounting portion and has a coupling for connecting one or both of the liquid piping and electrical wiring.

15. The coupling device according to claim 7, claim 8, claim 10, claim 13, or claim 14, wherein the first mounting portion has a mounting frame that is long in the vertical direction and includes an upper fixing member and a lower fixing member that connect to a fixing member of the work vehicle, and the mounting frame has an opening that penetrates in the front-rear direction from the work vehicle side to the work machine side.

16. A work vehicle comprising a vehicle body and a running gear for moving the vehicle body, wherein the vehicle body comprises an operating device protruding from the upper part of the vehicle body and a fixing part for attaching a coupling device for connecting work equipment to the vehicle body, the fixing part being located below the operating device and extending from the vehicle body toward the coupling device.

17. The work vehicle according to claim 16, further comprising a coupling device for connecting the work machine to the vehicle body, wherein the coupling device has a lifting mechanism for raising and lowering the work machine.

18. The work vehicle according to claim 16 or 17, wherein the operating equipment is equipment for operating the work machine or the coupling device.

19. The work vehicle according to any one of claims 16 to 18, wherein the fixing portion comprises a frame located at the lower part of the vehicle body and extending in the front-rear direction and protruding from the lower part, and a mounting block located at the front of the frame and to which the coupling device is attached.

20. The work vehicle according to any one of claims 16 to 19, wherein the operating equipment and the fixed part are arranged to overlap in a plan view, at least in part.

21. The work vehicle according to any one of claims 16 to 20, wherein the fixing portion comprises a frame located at the lower part of the vehicle body and extending in the front-rear direction and protruding from the lower part, and a mounting block located at the front of the frame and for attaching the coupling device, the mounting block having a vehicle-side coupling for connecting one or both of the pipes and wiring, and the frame having an opening through which one or both of the pipes and wiring extending from the vehicle-side coupling toward the vehicle body passes.

22. The work vehicle according to any one of claims 16 to 21, wherein the running gear is arranged on both the left and right sides of the vehicle body, and the mounting positions of the fixing part and the coupling device overlap with a part of the running gear in a side view.

23. The running gear has wheels positioned on the front, rear, left, and right sides of the vehicle body, and the mounting position of the fixing part and the coupling device overlaps with the wheels in a side view, as described in any one of claims 16 to 22.

24. The work vehicle according to claim 22, having a coupling device for connecting the work machine to the vehicle body, wherein the mounting positions of the coupling device and the work machine do not overlap with the running gear in a side view.

25. The work vehicle according to any one of claims 16 to 24, wherein the vehicle body comprises a central frame and a pair of side frames located on both sides of the central frame and displaceable relative to the central frame, and the running gear is attached to each of the pair of side frames and has displacement actuators that allow the central frame and the side frames to be displaced relative to each other in at least one of the left-right direction and the up-down direction.

26. The work vehicle according to any one of claims 16 to 25, wherein the vehicle body comprises a central frame having a battery and a case for housing the battery, and a pair of side frames located on both sides of the central frame and to which the running gear is attached, and the case is displaceable in the front-rear direction and housed in the central frame.

27. A work vehicle comprising: a vehicle body; a running device that enables the vehicle body to travel in at least three directions of travel; and a fixed part to which another device can be attached and which can output power energy to the other device, wherein the fixed part is provided at each of the positions corresponding to the at least three directions of travel.

28. The work vehicle according to claim 27, wherein at least one of the fixing parts is provided at a position on the direction of travel side.

29. The work vehicle according to claim 28, wherein at least one of the fixing parts is provided at a position opposite to the direction of travel.

30. The work vehicle according to claim 27 or 28, wherein at least one of the fixing parts is provided at a position different from the position corresponding to the direction of travel.

31. The work vehicle according to any one of claims 27 to 30, wherein the other equipment is a work machine or a coupling device for attaching a work machine.

32. The work vehicle according to any one of claims 27 to 31, wherein the at least three directions of travel are at least three of the directions of front, back, left, and right.

33. The work vehicle according to any one of claims 27 to 32, wherein the vehicle body further has the fixing portion at one or both of the upper and lower positions of the vehicle body.

34. A work vehicle according to any one of claims 27 to 33, which outputs the power energy to each of the multiple other devices attached to the multiple fixed parts.

35. The work vehicle according to any one of claims 27 to 34, wherein the vehicle body comprises a central frame and a pair of side frames located on both sides of the central frame and displaceable relative to the central frame, the running gear comprises front and rear wheels attached to each of the pair of side frames, and the fixing portion is provided on one or both of the pair of side frames.

36. The work vehicle according to any one of claims 27 to 35, wherein the fixed portion has a vehicle-side coupling for connecting one or both of the pipes and wiring.

37. The work vehicle according to any one of claims 27 to 36, wherein the other device has one or both of the following: a drive unit for operating the other device and a drive unit for operating yet another device attached via the other device, and the vehicle body has a power source for powering the drive unit.

38. The work vehicle according to any one of claims 27 to 37, wherein the work vehicle has a coupling device which is detachably attached to the fixed part and to which a work machine can be attached, and the coupling device has a lifting mechanism for raising and lowering the work machine and a motor that outputs power to the work machine.

39. The work vehicle according to any one of claims 27 to 38, wherein the vehicle body comprises a central frame and a pair of side frames located on both sides of the central frame and displaceable relative to the central frame, and the running gear is attached to each of the pair of side frames and has displacement actuators that allow the central frame and the side frames to be displaced relative to each other in at least one of the left-right direction and the up-down direction.

40. The work vehicle according to any one of claims 27 to 39, wherein the vehicle body comprises a central frame having a battery and a case for housing the battery, and a pair of side frames located on both sides of the central frame and to which the running gear is attached, and the case is displaceable in the front-rear direction and housed in the central frame.

41. A work vehicle comprising a vehicle body and a running device for moving the vehicle body, wherein the vehicle body has a fixing part for attaching other equipment to be attached and detached, the fixing part having a vehicle-side coupling for connecting one or both of piping and wiring, a cover, and a cover actuator for switching the cover between a first state and a second state, wherein the cover covers the connection port side of the vehicle-side coupling of the fixing part in the first state and opens the connection port side of the vehicle-side coupling of the fixing part in the second state.

42. The work vehicle according to claim 41, wherein the cover actuator starts operating when predetermined conditions are met.

43. The work vehicle according to claim 42, wherein the predetermined conditions are conditions relating to the state or operation of the vehicle body, conditions relating to the positional relationship between the vehicle body and the other equipment, or conditions relating to the identification of the other equipment.

44. The work vehicle according to any one of claims 41 to 43, wherein the cover actuator operates to open and close the cover when the vehicle body and the other device change relative positions when the other device is not attached to the fixed part.

45. The work vehicle according to any one of claims 41 to 44, wherein when the vehicle body proceeds to an operation step for connecting to the other device or an operation step after disconnecting from the other device in accordance with a set operation program, the cover actuator starts to operate.

46. ​​The work vehicle according to any one of claims 41 to 45, wherein the vehicle body has a detection device, and when the detection device detects the other device or identification information of the other device, the cover actuator starts to operate.

47. The work vehicle according to any one of claims 41 to 46, wherein the fixing part has a coupling part for mechanically connecting the other equipment, and the cover covers the vehicle-side coupling and the coupling part.

48. The work vehicle according to any one of claims 41 to 47, wherein the fixing part has a storage part for storing the cover in the second state.

49. The work vehicle according to any one of claims 41 to 48, wherein the other equipment is a work machine or a coupling device for attaching a work machine.

50. The work vehicle according to any one of claims 41 to 49, wherein the vehicle body comprises a central frame and a pair of side frames located on both sides of the central frame and displaceable relative to the central frame, and the running gear is attached to each of the pair of side frames and has displacement actuators that allow the central frame and the side frames to be displaced relative to each other in at least one of the left-right and up-down directions.

51. The work vehicle according to any one of claims 41 to 50, wherein the vehicle body comprises a central frame having a battery and a case for housing the battery, and a pair of side frames located on both sides of the central frame and to which the running gear is attached, and the case is displaceable in the front-rear direction and housed in the central frame.

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