Work vehicle

Abstract

A work vehicle having excellent operation stability is provided.　This work vehicle (1) comprises a vehicle body frame (10), a travel device (3) that supports the vehicle body frame such that the vehicle body frame can travel, and a battery unit (8). The vehicle body frame has a left frame (11L) that constitutes a left-side section of the vehicle body frame, and a right frame (11R) that is placed at a predetermined gap apart from and to the side of the left frame and that constitutes a right-side section of the vehicle body frame. The battery unit has a center unit (8C) that is positioned within the gap between the left frame and the right frame, a left unit (8L) connected to the center unit and positioned above the left frame, and a right unit (8R) connected to the center unit and positioned above the right frame.

Description

Work vehicle

[0001] The present invention relates to a work vehicle driven by an electric motor.

[0002] In recent years, in order to achieve decarbonization, the development of work vehicles driven by electric motors has been progressing. The work vehicle (tractor) disclosed in Patent Document 1 includes a fuel cell, an electric motor, and a battery unit, stores the electric power generated by the fuel cell in the battery unit, and drives the electric motor. For this type of work vehicle, in order to maintain stable output over a long period of time, it is required to increase the battery capacity as much as possible.

[0003] Japanese Patent Application Laid-Open Gazette "JP-A-2024-095105"

[0004] However, in this type of work vehicle, in addition to the battery unit, heavy objects such as a fuel cell and an electric motor are mounted. Therefore, in order to increase the battery capacity as described above, if the battery unit is enlarged, depending on the arrangement of the battery unit, the weight balance of the entire vehicle may be impaired, leading to a decrease in running stability. In addition, in order to maintain the high charging performance of the battery unit, an improvement in the cooling efficiency of the battery unit is also required.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a work vehicle excellent in operation stability.

[0006] The present invention employs the following technical means to achieve the above object.

[0007] A work vehicle according to an aspect of the present invention includes a vehicle body frame, a traveling device that supports the vehicle body frame so as to be capable of traveling, and a battery unit. The vehicle body frame includes a left frame that constitutes the left side portion of the vehicle body frame, and a right frame that is arranged in parallel with the left frame with a predetermined interval therebetween and constitutes the right side portion of the vehicle body frame. The battery unit includes a central unit located within the interval between the left frame and the right frame, a left unit connected to the central unit and located above the left frame, and a right unit connected to the central unit and located above the right frame.

[0008] According to this invention, the center of gravity of the entire vehicle can be set low, resulting in highly stable driving. Furthermore, this also allows for efficient cooling of the battery unit, thus maintaining high charging performance. As a result, a work vehicle with excellent operational stability can be provided.

[0009] This is a schematic diagram of a positioning support system. This is a perspective view of a work vehicle according to an embodiment of the present invention. This is an overhead view of a work vehicle according to an embodiment of the present invention. This is a side view of a work vehicle according to an embodiment of the present invention. This is a front view of a work vehicle according to an embodiment of the present invention. This is a rear view of a work vehicle according to an embodiment of the present invention. This is a partially exploded perspective view of a work vehicle according to an embodiment of the present invention. This is a block diagram showing the basic configuration of a work vehicle according to an embodiment of the present invention. This is a perspective view showing the vehicle frame and its surrounding parts. This is a partially exploded perspective view showing the vehicle frame and its surrounding parts. This is a perspective view of the vehicle frame. This is an overhead view of the vehicle frame. This is a schematic cross-sectional view of a battery unit from the front. This is a schematic perspective view of a battery unit. This is a schematic exploded perspective view of a battery unit. This is a schematic cross-sectional view of a battery unit from the top. This is a schematic cross-sectional view of a battery unit from the front of a first modified example. This is a schematic cross-sectional view of a battery unit from the front of a second modified example. This is a schematic cross-sectional view of a battery unit from the front of a third modified example. This is a schematic cross-sectional view of a battery unit from the front of a fourth modified example. This is a schematic cross-sectional view of a battery unit from the front of a fifth modified example. This is a schematic cross-sectional view of a battery unit from the top of a fifth modified example.

[0010] Embodiments of the present invention will be described with reference to the drawings. The work vehicle 1 of this embodiment is a type of FCV (Fuel Cell Vehicle) driven by electricity generated by a fuel cell, and can be used by connecting work implements U1 such as tillers, mowers, seeders, spreaders, and balers, mainly according to the purpose and use of agricultural work (see Figure 3). However, the work vehicle 1 according to the present invention is not limited to agricultural work vehicles. For example, the work vehicle 1 according to the present invention may be a construction work vehicle, a material transport vehicle, a utility vehicle, etc.

[0011] As shown in Figure 1, the work vehicle 1 of this embodiment is an autonomous vehicle that drives autonomously based on the position information of the work vehicle 1 acquired from the positioning support system S, obstacle detection information from the object sensor 95, etc. In addition to the autonomous driving function described above, or alternatively, the work vehicle 1 may also be equipped with a remote control function that allows it to be driven manually by commands from a remote control device RC.

[0012] The work vehicle 1 of this embodiment includes a control device 90, a positioning device 91, and a work information communication device 93. Based on an operation program set in advance by the user, the control device 90 sets a target travel route from information about the target field, etc., and controls the movement of the vehicle body 2 to follow the target travel route using the position information (positioning information) of the work vehicle 1 acquired from the positioning support system S.

[0013] The positioning support system S comprises a positioning base station S1 and a support device S2. Multiple positioning base stations S1 are installed at predetermined reference points such as building roofs and around fields, and transmit satellite signals received from positioning satellites G to the support device S2 via an external communication network N. The support device S2 is a fixed computer terminal (server) installed at agricultural machinery manufacturers, agricultural cooperatives, positioning support system management companies, etc., and transmits observation information based on satellite signals received from the positioning base stations S1 to the outside via the external communication network N.

[0014] The positioning device 91 acquires position information (positioning information including latitude and longitude) from satellite positioning systems such as GPS (Global Positioning System), GLONASS (Global Navigation Satellite System), Michibiki (QZSS: Quasi-Zenith Satellite System), Galileo, and Beidou. The positioning device 91 receives satellite signals (positioning information such as the position of the positioning satellite G and the transmission time) transmitted from the positioning satellite G, and detects the position of the work vehicle 1 (for example, latitude and longitude) based on the satellite signals.

[0015] The work information communication device 93 is a field management communication device that wirelessly connects to an external communication network N and transmits positioning information (vehicle position), operation information of the work vehicle 1, operation information of the work device U1 connected to the work vehicle 1, etc., to the field management device T. The work information communication device 93 in this embodiment is a communication unit that can wirelessly connect to an external communication network N via a communication base station such as a telephone communication network of a telephone line operator or a data communication network of an internet line operator, and transmits positioning information and operation information to the field management device T via the external communication network N.

[0016] The work vehicle 1 may be equipped with a remote communication device 94. The remote communication device 94 is a communication device for remote operation that receives radio waves emitted from the remote control device RC and acquires operation information (operation command information) for the remote control device RC. The remote communication device 94 is wired to the control device 90 and transmits the operation information to the control device 90.

[0017] The work vehicle 1 is equipped with an object sensor 95. The control device 90 controls the movement of the vehicle body 2 based on the detection information from the object sensor 95. In this embodiment, the object sensor 95 is an imaging device that photographs the area around the work vehicle 1 and transmits the captured image to the control device 90. Based on the image, the control device 90 detects whether or not there are any objects around the work vehicle 1 that would obstruct its movement.

[0018] In this embodiment, the work vehicle 1 uses imaging devices such as a CCD (Charge Coupled Devices) camera, a CMOS (Complementary Metal Oxide Semiconductor) camera, or an infrared camera as the object sensor 95. However, the object sensor 95 is not limited to imaging devices as long as it can accurately detect the presence or absence of objects around the work vehicle 1.

[0019] For example, the object sensor 95 may be a laser sensor (LiDAR: Light Detection And Ranging) that irradiates laser light around the work vehicle 1 and measures the distance and position of an object based on the detection information of the reflected light. Alternatively, the object sensor 95 may be a millimeter-wave radar that irradiates radio waves around the work vehicle 1 and measures the distance and position of an object based on the detection information of the reflected waves.

[0020] The work vehicle 1 may be equipped with two or more sensors as object sensors 95, selected from an imaging device, a laser sensor, and a millimeter-wave radar, and may be configured to detect objects around the work vehicle 1 in combination with these multiple types of sensors.

[0021] The control device 90 is an ECU (Electronic Control Unit) and controls the running gear 3, power supply device 4, electric motor 5, etc. The control device 90 controls the movement of the vehicle body 2 based on information from the positioning device 91, work information communication device 93, object sensor 95, etc.

[0022] In more detail, the control device 90 sets a target travel path for the work vehicle 1 based on positioning information acquired by the positioning device 91. The control device 90 controls the steering direction of the travel device 3, the output of the electric motor 5, etc., according to the target travel path. In this way, the control device 90 autonomously controls the movement of the vehicle body 2.

[0023] The control device 90 may control the steering direction of the driving device 3, the output of the electric motor 5, the operation of the braking device 2E, etc., based on the operation information acquired by the remote communication device 94. In other words, the control device 90 may control the movement of the vehicle body 2 by command (remote control) from the remote control device RC. This allows the operator to remotely control the movement of the vehicle body 2 using the remote control device RC.

[0024] The control device 90 of this embodiment combines an autonomous driving function that controls the movement of the vehicle body 2 autonomously and a remote control function that controls the movement of the vehicle body 2 remotely. However, the control device 90 is not limited to having both the autonomous driving function and the remote control function. For example, the control device 90 may have only one of the autonomous driving function or the remote control function.

[0025] The control device 90 analyzes whether or not there are obstacles around the work vehicle 1 based on the detection information (image information) from the object sensor 95. The control device 90 restricts the operation of the work vehicle 1 according to the results of the image information analysis.

[0026] For example, if the control device 90 detects a person or an obstacle (object) that would hinder movement on the target driving path using the object sensor 95 during autonomous driving, and the distance from the obstacle to the work vehicle 1 is below a predetermined value, the control device 90 reduces the output of the electric motor 5 and activates the braking device 2E mounted on the vehicle body 2 to stop the work vehicle 1.

[0027] Furthermore, if the object sensor 95 is a laser sensor or millimeter-wave radar, the control device 90 analyzes whether or not there are obstacles around the work vehicle 1 based on the detection information (input information) from the laser sensor or millimeter-wave radar, instead of image information. The control device 90 then performs the same stopping operation on the work vehicle 1 as described above, according to the results of the analysis of the input information.

[0028] In the following explanation, the longitudinal direction of the vehicle body 2, which is the direction of straight-line travel of the work vehicle 1 (indicated by arrows X1 and X2 in Figures 2 to 4), will be referred to as the front-rear direction, the width direction of the vehicle body 2 (indicated by arrows Y1 and Y2 in Figures 2, 3, 5, and 6), will be referred to as the left-right direction, and the height direction of the vehicle body 2 (indicated by arrows Z1 and Z2 in Figures 2, 4 to 6), will be referred to as the up-down direction. Furthermore, in each figure, the direction indicated by arrow X1 will be referred to as the front, the direction indicated by arrow X2 as the rear, the direction indicated by arrow Y1 as the left, the direction indicated by arrow Y2 as the right, the direction indicated by arrow Z1 as the up, and the direction indicated by arrow Z2 as the down.

[0029] As shown in Figures 2 to 6, the work vehicle 1 comprises a body 2 and a running gear 3. The running gear 3 supports the body 2 so that it can move. That is, the work vehicle 1 has a drivable body 2. The running gear 3 of this embodiment includes a front wheel 3F as a front running gear that supports the front of the body 2, and a rear wheel 3R as a rear running gear that supports the rear of the body 2. As shown in Figures 3 and 5, the running gear 3 of this embodiment includes a left front wheel 3A as a left running gear and a right front wheel 3B as a right running gear.

[0030] Furthermore, the running gear 3 is not limited to wheels. For example, the running gear 3 may be a crawler. Also, of the running gear 3 that supports the front and rear of the vehicle body 2, one may be wheels and the other may be a crawler.

[0031] As shown in Figures 4, 7, and 8, the work vehicle 1 is equipped with a power supply device 4, an electric motor 5, and a power transmission device 20. The power supply device 4 includes a hydrogen tank 6, a fuel cell stack (fuel cell) 7, and a battery unit 8. In other words, the power supply device 4 is a device for supplying power to the electric motor 5 and the like.

[0032] The hydrogen tank 6 stores hydrogen gas. The fuel cell stack 7 generates electricity using the hydrogen gas supplied from the hydrogen tank 6 and supplies it to the electric motor 5. The battery unit 8 stores the electricity generated by the fuel cell stack 7 and supplies it to the electric motor 5 as needed. The electric motor 5 is driven by the electricity supplied from the fuel cell stack 7 and the battery unit 8. The power transmission device 20 transmits the power from the electric motor 5 to the traction device 3.

[0033] As shown in Figure 8, the work vehicle 1 is equipped with a hydraulic pump 9. The work vehicle 1 may also be equipped with a radiator device 61. The work vehicle 1 may further be equipped with an inverter 62 and a DC / DC converter 63.

[0034] The radiator system 61 is a cooler that cools the coolant (refrigerant) circulated to equipment such as the electric motor 5, fuel cell stack 7, inverter 62, and DC / DC converter 63 by heat exchange with the outside air. The radiator system 61 includes a first radiator system 66 and a second radiator system 67.

[0035] The first radiator unit 66 is connected to the electric motor 5, inverter 62, DC / DC converter 63, and boost circuit BC via a first coolant flow path FP1, and cools the coolant circulating through the first coolant flow path FP1 by heat exchange with the outside air. As a result, the electric motor 5, inverter 62, DC / DC converter 63, and boost circuit BC are maintained at a predetermined temperature or below.

[0036] The first radiator unit 66 is housed inside the rear bonnet 15B. The fuel cell stack 7, inverter 62, DC / DC converter 63, and boost circuit BC are also housed inside the rear bonnet 15B, similar to the first radiator unit 66.

[0037] The first radiator device 66 includes a first heat exchange section 71 and a first fan 72. The first heat exchange section 71 is a gas-liquid heat exchanger composed of a plurality of heat transfer fins and heat transfer tubes, and is connected to a first coolant flow path FP1. The first fan 72 circulates air over the surface of the first heat exchange section 71, promoting heat exchange between the air and the coolant flowing inside the first heat exchange section 71. The first radiator device 66 may have only one first fan 72, or it may have two or more first fans 72.

[0038] The first fan 72, when driven, draws air from outside the rear bonnet 15B into the rear bonnet 15B. The air drawn into the rear bonnet 15B by the first fan 72, as described above, passes through the first heat exchange unit 71, then passes around the fuel cell stack 7, inverter 62, and DC / DC converter 63, and is discharged to the outside of the rear bonnet 15B. As a result, the coolant flowing through the first heat exchange unit 71 is cooled efficiently. The air that has passed through the first heat exchange unit 71 also promotes the cooling of the fuel cell stack 7, inverter 62, and DC / DC converter 63.

[0039] The second radiator device 67 is connected to the fuel cell stack 7 via a second coolant flow path FP2, and cools the coolant circulating through the second coolant flow path FP2 by heat exchange with the outside air. As a result, the internal electrodes of the fuel cell stack 7 are maintained at a predetermined temperature or below. Consequently, the fuel cell stack 7 maintains a high power generation efficiency.

[0040] The second radiator unit 67 is housed inside the front bonnet 15A. The hydrogen tank 6 and battery unit 8 are also housed inside the front bonnet 15A, similar to the second radiator unit 67.

[0041] The second radiator device 67 includes a second heat exchange section 73 and a second fan 74. The second heat exchange section 73 is a gas-liquid heat exchanger composed of a plurality of heat transfer fins and heat transfer tubes, and is connected to the second coolant flow path FP2. The second fan 74 circulates air over the surface of the second heat exchange section 73, promoting heat exchange between the air and the coolant flowing inside the second heat exchange section 73. The second radiator device 67 may have only one second fan 74, or it may have two or more second fans 74.

[0042] The second fan 74, when driven, draws air from outside the front bonnet 15A into the front bonnet 15A. The air drawn into the front bonnet 15A by the second fan 74, as described above, passes through the second heat exchange section 73, then passes around the hydrogen tank 6 and battery unit 8, and is discharged to the outside of the front bonnet 15A. As a result, the coolant flowing through the second heat exchange section 73 is cooled efficiently. The air that has passed through the second heat exchange section 73 also promotes the cooling of the hydrogen tank 6 and battery unit 8.

[0043] As shown in Figures 3, 4, and 6, the work vehicle 1 is equipped with a coupling device 60. The coupling device 60 is located at the rear of the vehicle body 2 and connects to and supports the work device U1. That is, the work vehicle 1 is equipped with a vehicle body 2 that is drivable and capable of mounting the work device U1. In this embodiment, the coupling device 60 is a three-point linkage mechanism that connects to and raises the work device U1. The coupling device 60 has a hydraulic cylinder for raising and lowering the work device U1.

[0044] As shown in Figures 9 to 11, the vehicle body 2 has a vehicle body frame 10. The vehicle body frame 10 includes a front frame 11 and a transmission case 12. As shown in Figures 11 and 12, the vehicle body frame 10 may further include a central frame 13. The front frame 11 constitutes the front part of the vehicle body frame 10. The transmission case 12 constitutes the rear part of the vehicle body 2. The central frame 13 is provided at the front and rear of the front frame 11 and the transmission case 12, and connects the front frame 11 and the transmission case 12. That is, the central frame 13 constitutes the base frame in the center between the front and rear of the vehicle body 2.

[0045] As shown in FIGS. 9 to 12, the front frame 11 has a left frame 11L and a right frame 11R. The left frame 11L constitutes the left side portion of the front frame 11. The right frame 11R constitutes the right side portion of the front frame 11. As shown in FIGS. 3 and 5, the left front wheel 3A is disposed on the left side portion of the left frame 11L. The right front wheel 3B is disposed on the right side portion of the right frame 11R.

[0046] As shown in FIGS. 9 to 12, both the left frame 11L and the right frame 11R are plate-shaped frames that are long in the front-rear direction, and are arranged side by side facing each other in the left-right direction. A predetermined interval H1 is defined between the left and right of the left frame 11L and the right frame 11R. That is, the left frame 11L and the right frame 11R are arranged side by side with a predetermined interval H1 in the left-right direction.

[0047] As shown in FIGS. 11 to 13, the front frame 11 of the vehicle body frame 10 has a mounting flange 11T and a bottom frame 11U. The mounting flange 11T is provided along the left part of the upper edge of the left frame 11L and the right part of the upper edge of the right frame 11R, respectively. The bottom frame 11U extends between the lower edges of the left frame 11L and the right frame The bottom frame 11U is arranged in parallel in the front-rear direction with a gap at the lower part of the front frame 11. The battery unit 8 is attached to the mounting flange 11T and the bottom frame 11U. Details of the battery unit 8 will be described later.

[0048] As shown in FIG. 12, the front frame 11 has a front axle case 11C. The front axle case 11C houses the front axle 3FD. The front axle 3FD is connected to the left and right front wheels 3F and transmits the power of the electric motor 5 to the front wheels 3F. As shown in FIGS. 5 and 10 to 12, the front axle case 11C is continuously provided at the lower part of the front frame 11. The front frame 11 is supported from below by the front wheels 3F via the front axle case 11C. In this way, the front wheels 3F are supported by the front frame 11. <00As shown in Figures 11 and 12, the power transmission device 20 has a transmission case 12. The transmission case 12 is the housing of the power transmission device 20. The transmission case 12 may include a rear axle case 12C. The rear axle case 12C extends outward from the side of the transmission case 12 and houses the rear axle 3RD. The rear axle 3RD is connected to the left and right rear wheels 3R ​​and transmits power from the electric motor 5 to the rear wheels 3R. The transmission case 12 is supported laterally by the rear wheels 3R ​​via the rear axle case 12C. In this way, the rear wheels 3R ​​are supported by the transmission case 12.

[0050] The central frame 13 has a rectangular box-shaped frame structure. The electric motor 5 is incorporated into the space inside the central frame 13. The central frame 13 has a connecting bracket 13B. The central frame 13 is connected to the front of the transmission case 12 via the connecting bracket 13B. The electric motor 5 is connected to the front of the connecting bracket 13B. The electric motor 5 is connected to the front of the transmission case 12 via the connecting bracket 13B. Details of the electric motor 5 will be described later.

[0051] As shown in Figures 9 and 10, the vehicle body 2 may have a support frame 14. The support frame 14 in this embodiment has a frame structure that is long in the front-rear direction. The support frame 14 is provided on the upper part of the vehicle body frame 10. The support frame 14 in this embodiment extends from the front part of the front frame 11 to the rear part of the transmission case 12.

[0052] The support frame 14 includes a front support frame 14A and a rear support frame 14B. The front support frame 14A is connected and supported to the upper part of the front frame 11. The rear support frame 14B is connected and supported to the upper part of the transmission case 12.

[0053] The rear support frame 14B may have a support base portion 14C. The support base portion 14C has a rectangular box-shaped frame structure. As shown in Figure 4, the fuel cell stack 7 is supported on the upper part of the support base portion 14C. The fuel cell stack 7 is supported on the upper part of the transmission case 12 via the support frame 14. That is, the fuel cell stack 7 is located at the rear of the vehicle body 2. Details of the fuel cell stack 7 will be described later.

[0054] As shown in Figures 2 to 7, the vehicle body 2 has a bonnet 15. The bonnet 15 is a cover member that covers the equipment mounted on the upper part of the vehicle body 2. The bonnet 15 may be composed of multiple parts. In this embodiment, the bonnet 15 includes a front bonnet 15A and a rear bonnet 15B. The front bonnet 15A is provided on the upper part of the front frame 11. The rear bonnet 15B is provided on the upper part of the transmission case 12.

[0055] As shown in Figures 2 to 4 and Figure 7, the vehicle body 2 has a tank frame 16. The tank frame 16 is formed in a roughly rectangular box shape by a plurality of frames and plate materials. The tank frame 16 is connected and supported to the upper part of the front support frame 14A. The hydrogen tank 6 is housed inside the tank frame 16 and is supported to the upper part of the front frame 11 via the tank frame 16. In other words, the hydrogen tank 6 is located at the front of the vehicle body 2. Details of the hydrogen tank 6 will be described later.

[0056] As shown in Figure 8, the hydraulic pump 9 is connected to the power transmission device 20. The hydraulic pump 9 is connected to the transmission case 12 and is rotationally driven by the power of the electric motor 5 transmitted from the power transmission device 20. The hydraulic drive system, which includes the hydraulic cylinder for steering the running gear 3 and the hydraulic cylinder for driving the coupling device 60, is connected to the hydraulic pump 9 through a hydraulic circuit and is driven by the hydraulic fluid (pressurized oil) discharged from the hydraulic pump 9.

[0057] As shown in Figures 6 and 8, the vehicle body 2 has a PTO shaft (power take-off shaft) 2D. The PTO shaft 2D is located at the rear of the power transmission device 20 and is rotationally driven by the power of the electric motor 5 transmitted from the power transmission device 20. When the working device U1 is connected to the coupling device 60 (see Figure 6), the PTO shaft 2D is connected to the passive shaft of the working device U1 via a universal joint. The power of the electric motor 5 is transmitted from the PTO shaft 2D to the passive shaft of the working device U1 via the universal joint. In other words, the working device U1 is driven by the power of the electric motor 5.

[0058] The electric motor 5 is, for example, a three-phase AC synchronous motor with embedded permanent magnets. However, the electric motor 5 is not limited to a three-phase AC synchronous motor. For example, the electric motor 5 may be a synchronous motor in which coils are wound around a rotor and laminated steel plates are fitted to it. The electric motor 5 is not limited to an AC motor, but may also be a DC motor.

[0059] As shown in Figures 2 to 4 and Figures 8 to 12, the electric motor 5 includes a first motor 5A and a second motor 5B. The first motor 5A is a drive system motor that drives the travel device 3. That is, the first motor 5A generates the driving force for the vehicle body 2. The second motor 5B is a work system motor that drives the PTO shaft 2D. That is, the second motor 5B generates the driving force for the work device U1. The power transmission device 20 is configured to transmit the power of the second motor 5B to the PTO shaft 2D and also to the hydraulic pump 9.

[0060] As shown in Figures 3 and 4, both the first motor 5A and the second motor 5B are positioned in the center between the front and rear of the vehicle body 2. In this embodiment, both the first motor 5A and the second motor 5B are positioned in the center between the front and rear of the front wheel 3F and the rear wheel 3R.

[0061] The hydrogen tank 6 is located above the first motor 5A and the second motor 5B. That is, the first motor 5A and the second motor 5B are located below the hydrogen tank 6. The fuel cell stack 7 is located above and behind the first motor 5A and the second motor 5B. That is, the first motor 5A and the second motor 5B are located below and in front of the fuel cell stack 7. The battery unit 8 is located in front of the first motor 5A and the second motor 5B. That is, the first motor 5A and the second motor 5B are located behind the battery unit 8.

[0062] The power transmission device 20 is a device that reduces or increases the speed of the electric motor 5 and transmits it to the running gear 3. The power transmission device 20 is configured to transmit power not only to the running gear 3 but also to the hydraulic pump 9 and the PTO shaft 2D.

[0063] The power transmission device 20 of this embodiment is configured to be switchable between a two-wheel drive state in which the power of the electric motor 5 is transmitted only to the rear wheels 3R ​​of the running gear 3, and a four-wheel drive state in which the power of the electric motor 5 is transmitted to both the front wheels 3F and the rear wheels 3R. That is, the work vehicle 1 of this embodiment is a four-wheel drive vehicle capable of running with both the front wheels 3F and the rear wheels 3R ​​as drive wheels, and is configured to be able to be arbitrarily switched to a two-wheel drive vehicle state in which only the rear wheels 3R ​​are driven wheels, in response to an operation program set in advance by the user or a command from the remote control device RC. Note that the work vehicle 1 may be a two-wheel drive vehicle that runs with only the front wheels 3F as drive wheels, or a two-wheel drive vehicle that runs with only the rear wheels 3R ​​as drive wheels.

[0064] As shown in Figures 2 to 5, the hydrogen tank 6 is a roughly cylindrical container that stores hydrogen gas under high pressure. The hydrogen tank 6 is made of, for example, a rigid synthetic resin reinforced with carbon fiber or glass fiber. As shown in Figure 8, the work vehicle 1 is equipped with a gas filling port (receptacle) 2G and a valve device V1.

[0065] The hydrogen tank 6 is connected to a gas supply unit installed at a hydrogen gas station via a gas filling port 2G, and hydrogen gas is filled into the hydrogen tank 6 through a valve device V1 via the gas filling port 2G and stored in the hydrogen tank 6. The valve device V1 consists of an on-off valve, a pressure reducing valve, a check valve, etc., and introduces the hydrogen gas injected into the gas filling port 2G into the hydrogen tank 6. The valve device V1 adjusts the hydrogen gas in the hydrogen tank 6 to a predetermined flow rate and then leads it out to the fuel cell stack 7. In addition, the hydrogen tank 6 may be configured to be replaced with another hydrogen tank 6 that is pre-filled with hydrogen gas when the amount of hydrogen gas stored becomes low, rather than being replenished with hydrogen gas from the gas filling port 2G as described above.

[0066] As shown in Figures 2 to 5, the hydrogen tank 6 is located at the front of the vehicle body 2. The hydrogen tank 6 is positioned on top of the front frame 11 and is covered by the front bonnet 15A together with the tank frame 16. In other words, the hydrogen tank 6 is housed inside the front bonnet 15A.

[0067] The work vehicle 1 of this embodiment is equipped with two hydrogen tanks 6. These two hydrogen tanks 6 are installed side by side on the front of the vehicle body 2. Note that more than two hydrogen tanks 6 may be mounted on the vehicle body 2. For example, three hydrogen tanks 6 may be installed side by side on the front of the vehicle body 2, or four hydrogen tanks 6 may be installed in a 2x2 arrangement vertically and horizontally on the front of the vehicle body 2.

[0068] The fuel cell stack 7 generates electricity using hydrogen gas supplied from the hydrogen tank 6 and supplies power to the electric motor 5. The fuel cell stack 7 is composed of multiple single cells, each equipped with two types of electrodes, a positive electrode and a negative electrode, arranged in a stacked configuration inside a casing. By aggregating the electricity generated by each single cell, it generates the voltage and current power required to drive the electric motor 5.

[0069] As shown in Figure 8, the fuel cell stack 7 is connected to the inverter 62 and battery unit 8 via a boost circuit BC. The boost circuit BC increases the voltage of the power generated by the fuel cell stack 7. That is, the fuel cell stack 7 supplies the power increased by the boost circuit BC to the inverter 62 and battery unit 8. The inverter 62 is connected to the electric motor 5 and converts the DC power input from the boost circuit BC into three-phase AC power, which is then output to the electric motor 5. In this way, the fuel cell stack 7 drives the electric motor 5 with the power increased by the boost circuit BC.

[0070] The fuel cell stack 7 is connected to low-voltage devices that operate at a lower voltage than the electric motor 5 via a step-down circuit. The step-down circuit is a DC / DC converter 63. In this embodiment, the low-voltage devices include a first fan 72, a second fan 74 of the radiator device 61, and a battery unit 8. The DC / DC converter 63 converts the voltage of the DC power input from the fuel cell stack 7 to an even lower voltage and outputs it to each of the low-voltage devices. In this way, the fuel cell stack 7 supplies power stepped down by the DC / DC converter 63 to each of the low-voltage devices.

[0071] The battery unit 8 is a rechargeable secondary battery that stores power supplied from the fuel cell stack 7 and outputs the stored power to the inverter 62 as needed. The battery unit 8 absorbs excess power from the fuel cell stack 7 and assists the output of the fuel cell stack 7. As shown in Figures 3, 4, and 12, the battery unit 8 is located at the front of the vehicle body 2. As shown in Figure 12, the battery unit 8 is located between the left front wheel 3A and the right front wheel 3B on the vehicle body frame 10. In this embodiment, the battery unit 8 is located above the front wheel 3F on the vehicle body frame 10.

[0072] As shown in Figures 13 to 16, the battery unit 8 includes a plurality of battery modules 8A and a battery case 80. The battery unit 8 may also include a cooling device 81. Furthermore, the battery unit 8 may also include a hot air outlet duct 82 and a cold air introduction duct 83.

[0073] The battery module 8A is composed of lithium-ion batteries, lead-acid batteries, etc. The battery case 80 houses multiple battery modules 8A arranged in the front-to-back, left-to-right, and up-to-down directions. Thus, the battery unit 8 is a battery pack that is integrally constructed by housing multiple battery modules 8A inside the battery case 80.

[0074] The battery case 80 of this embodiment has a sealed structure that can house the battery module 8A in a sealed state. In other words, the battery unit 8 of this embodiment is a sealed battery. As described above, by using a sealed case for the battery case 80, it is possible to prevent mud splashes, dust, rainwater, etc. generated around the front wheel 3F during driving from adhering to the battery module 8A.

[0075] The battery unit 8 comprises a central unit 8C, a left unit 8L, and a right unit 8R. The left unit 8L is located on the upper left side of the central unit 8C. The right unit 8R is located on the upper right side of the central unit 8C. Thus, the battery unit 8 is configured in a T-shape when viewed from the front, consisting of the central unit 8C, the left unit 8L, and the right unit 8R.

[0076] As shown in Figure 13, the central unit 8C is located within the distance H1 between the left frame 11L and the right frame 11R. The left unit 8L is located above the left frame 11L. The right unit 8R is located above the right frame 11R.

[0077] The central unit 8C is fixed to the upper part of the bottom frame 11U. The left frame 11L and the right frame 11R are each fixed to the upper part of the mounting flange 11T. In this way, the battery unit 8 is supported and fixed to the mounting flange 11T and the bottom frame 11U with the lower part of the central unit 8C embedded in the inner gap H1 of the front frame 11.

[0078] In this embodiment, the battery unit 8 is fixed to the upper part of the front frame 11 such that the center of gravity of the battery unit 8 (for example, the center position between the left and right sides of the battery unit 8) coincides with the Z-axis centerline CL3 that passes through the center between the left and right sides of the vehicle frame 10 when viewed from the front and rear directions. As a result, the weight of the battery unit 8 is added to the center between the left and right sides of the vehicle frame 10, thus stabilizing the overall weight balance of the work vehicle 1.

[0079] As shown in Figures 14 to 16, the battery module 8A is divided into two blocks, front and rear, inside the central unit 8C. The battery module 8A includes a first battery module BM1 and a second battery module BM. The first battery module BM1 is located in the front part of the central unit 8C. The second battery module BM is located in the rear part of the central unit 8C. Thus, the first battery module BM1 and the second battery module BM are arranged front to back inside the central unit 8C.

[0080] The cooling device 81 includes a cooling duct 84, a circulation fan 85, and an external heat sink 86. The cooling device 81 may also have an internal heat sink 87. The cooling device 81 may also have a cooling fan 88. Details of each component of the cooling device 81 will be described later.

[0081] As shown in Figures 15 and 16, the hot air outlet duct 82 is a cylindrical body that is flattened in the front-rear direction and is provided on the opposing surfaces of the first battery module BM1 and the second battery module BM2 in the central unit 8C. The hot air outlet duct 82 is provided in the center between the front and rear of the central unit 8C and connects the internal space of the central unit 8C to the cooling duct 84.

[0082] The internal air (hot air) of the central unit 8C, which contains heat generated from each battery module 8A, is guided into the cooling duct 84 through the hot air outlet duct 82. Thus, the hot air outlet duct 82 is provided on the opposing surfaces of the first battery module BM1 and the second battery module BM2, and constitutes a warm air passage F1 that guides the air that has passed through the battery modules 8A into the cooling duct 84.

[0083] The cold air intake duct 83 is a cylindrical body that is flattened in the front-rear direction and is provided on the front of the first battery module BM1 in the central unit 8C and on the rear of the second battery module BM2 in the central unit 8C, respectively. The cold air intake duct 83 is provided on the outer side of the central unit 8C in the front-rear direction and connects the internal space of the central unit 8C to the cooling duct 84.

[0084] The air (cold air) cooled by heat exchange inside the cooling duct 84 is guided into the central unit 8C through the cold air introduction duct 83. Thus, the cold air introduction duct 83 is provided on the outer surface of the first battery module BM1 opposite to the second battery module BM2, and on the outer surface of the second battery module BM2 opposite to the first battery module BM1, forming a cold air passage F2 that guides the air that has passed inside the cooling duct 84 to the battery module 8A.

[0085] As shown in Figures 13 and 15, the cooling duct 84 is a rectangular cylindrical body that extends in the front-rear direction along the side surface of the central unit 8C. In this embodiment, the cooling duct 84 is provided on the left side surface of the central unit 8C and constitutes the outer casing of the left unit 8L. Two cooling ducts 84 are provided side by side, front to back, on the side surface of the central unit 8C. Alternatively, the cooling duct 84 may be provided on the right side surface of the central unit 8C as the outer casing of the right unit 8R.

[0086] As described above, the cooling duct 84 is connected to the interior of the central unit 8C through the hot air outlet duct 82 and the cold air introduction duct 83, and constitutes a circulation path for the internal air of the central unit 8C within the battery unit 8. In other words, the cooling duct 84 constitutes an internal air circulation path that is shielded from the external space of the battery unit 8 between itself and the central unit 8C.

[0087] The cooling duct 84 is made of a material with high thermal conductivity, and cools the air passing through the cooling duct 84 by heat exchange with the outside air of the battery unit 8. In other words, the cooling duct 84 absorbs heat from the air passing through it and releases it to the outside of the battery unit 8.

[0088] As shown in Figures 13 to 16, the circulation fan 85 is installed inside the cold air introduction duct 83 and circulates air between the central unit 8C and the cooling duct 84. As shown in Figures 15 and 16, the circulation fan 85 is installed in the cold air passage F2.

[0089] The circulation fan 85 may include a first circulation fan 85A and a second circulation fan 85B. In this embodiment, of the first circulation fan 85A and the second circulation fan 85B, the first circulation fan 85A is installed inside the cold air introduction duct 83. On the other hand, the second circulation fan 85B is installed at the connection point between the hot air outlet duct 82 and the cooling duct 84, and when operated, it circulates air between the central unit 8C and the cooling duct 84. In this way, the work vehicle 1 of this embodiment circulates air between the central unit 8C and the cooling duct 84 using two circulation fans 85. This makes it possible to cool the battery unit 8 more efficiently.

[0090] As shown in Figures 13 to 15, the external heat sink 86 is a component having a plurality of heat dissipation fins 86F and is made of a material with high thermal conductivity. In this embodiment, the external heat sink 86 is provided such that the heat dissipation fins 86F extend in the front-rear direction of the vehicle body 2.

[0091] The external heat sink 86 is provided on the outside of the cooling duct 84 and cools the cooling duct 84 by heat exchange with the outside air of the battery unit 8. In this embodiment, the external heat sink 86 is provided on the upper surface of the cooling duct 84. The cooling duct 84 may also have a liquid cooling structure that cools the cooling duct 84 by heat exchange with a coolant supplied from outside the battery unit 8.

[0092] As shown in Figures 13 and 15, the internal heat sink 87 is a component having a plurality of heat-absorbing fins 87F and is made of a material with high thermal conductivity. In this embodiment, the external heat sink 86 is provided such that the heat-absorbing fins 87F extend in the same direction as the extension direction of the cooling duct 84. The internal heat sink 87 is provided inside the cooling duct 84 and cools the internal air of the central unit 8C introduced into the cooling duct 84 by heat exchange with the cooling duct 84.

[0093] As shown in Figures 13 to 15, the cooling fan 88 is installed on the outside of the cold air intake duct 83, next to the external heat sink 86, and supplies external air from the battery unit 8 to the external heat sink 86. The cooling fan 88 is installed adjacent to the end of the heat dissipation fins 86F of the external heat sink 86 in the direction of extension, and circulates the external air in the direction of extension of the heat dissipation fins 86F.

[0094] As described above, in this embodiment, the battery unit 8 is equipped with a cooling device 81 in the left unit 8L. On the other hand, as shown in Figures 13 to 16, electrical components E1 are stored in the right unit 8R. The electrical components E1 include a control device 90, a work information communication device 93, a remote communication device 94, an auxiliary battery, etc. Note that the right unit 8R may store hydraulic equipment in addition to electrical components E1.

[0095] The right unit 8R and the central unit 8C maintain an internal seal. Therefore, hot air from inside the central unit 8C does not flow into the right unit 8R. This reduces the thermal load on the electrical component E1, even when it is placed near the battery module 8A.

[0096] As shown in Figures 14 and 15, the right unit 8R may have a ventilation opening 8H that penetrates the inside and outside of the right unit 8R. By providing the right unit 8R with a ventilation opening 8H in this way, the rise in the internal temperature of the right unit 8R can be suppressed.

[0097] <Modifications> In the battery unit 8 of the above embodiment, the external heat sink 86 is provided on the upper surface of the cooling duct 84. However, in the first modified battery unit 8, as shown in Figure 17, the external heat sink 86 may be provided on the side surface of the cooling duct 84, or in the second modified battery unit 8, as shown in Figure 18, it may be provided on the lower surface of the cooling duct 84.

[0098] Alternatively, as shown in Figure 19, in the third modified battery unit 8, the external heatsink 86 may be provided on any two of the top, side, and bottom surfaces of the cooling duct 84 (for example, the top and bottom surfaces of the cooling duct 84), or as shown in Figure 20, in the fourth modified battery unit 8, it may be provided on all three surfaces: the top, side, and bottom surfaces. As in these third and fourth modified battery unit 8s, by providing multiple external heatsinks 86 on the outside of the cooling duct 84, the battery unit 8 can be cooled more efficiently.

[0099] In the battery unit 8 of the above embodiment, the cooling device 81 is provided only on the left side of the battery unit 8 (left unit 8L). However, in the fifth modified battery unit 8, as shown in Figures 21 and 22, the cooling device 81 may be provided on both the left and right sides of the battery unit 8 (left unit 8L and right unit 8R). By providing the cooling device 81 on both the left and right sides of the battery unit 8, as in this fifth modified battery unit 8, it becomes possible to cool the battery unit 8 more efficiently.

[0100] The present invention provides a work vehicle 1 as described in the following items.

[0101] (Item 1) A work vehicle 1 comprising a vehicle frame 10, a running device 3 that supports the vehicle frame 10 so that it can move, and a battery unit 8, wherein the vehicle frame 10 has a left frame 11L that constitutes the left side of the vehicle frame 10, and a right frame 11R that is arranged side by side with a predetermined distance between the left frame 11L and constitutes the right side of the vehicle frame 10, and the battery unit 8 has a central unit 8C located within the distance H1 between the left frame 11L and the right frame 11R, a left unit 8L connected to the central unit 8C and located above the left frame 11L, and a right unit 8R connected to the central unit 8C and located above the right frame 11R.

[0102] According to the work vehicle 1 related to item 1, the central unit 8C of the heavy battery unit 8 is positioned within the central space H1 between the left and right sides of the vehicle frame 10, making it possible to set a low center of gravity for the entire vehicle. This enables highly stable driving. In other words, it is possible to create a work vehicle with excellent operational stability.

[0103] Furthermore, in this design, the left unit 8L and the right unit 8R, which constitute part of the battery unit 8, are positioned above the vehicle frame 10, making it easier to stabilize the overall weight balance of the vehicle. Therefore, a more stable driving experience can be achieved.

[0104] Furthermore, in this design, the left unit 8L and the right unit 8R of the battery unit 8 are positioned above the vehicle frame 10, allowing for efficient cooling of the battery unit 8 even if a portion of the battery unit 8 (the central unit 8C) is embedded inside the vehicle frame 10, as described above. This also maintains the high charging performance of the battery unit 8. In other words, it is possible to realize a work vehicle with superior operational stability.

[0105] (Item 2) The work vehicle 1 according to Item 1, wherein the running gear 3 includes a left running gear 3A located on the left side of the left frame 11L and a right running gear 3B located on the right side of the right frame 11R, and the battery unit 8 is located between the left running gear 3A and the right running gear 3B on the vehicle body frame 10.

[0106] If a heavy object is positioned further to the left or right than the center between the left and right sides of the vehicle body 2, it will exacerbate the rolling motion of the vehicle body 2 during travel (the direction of rotation from side to side around the X-axis centerline CL1). However, in the work vehicle 1 described in item 2, the battery unit 8 is supported between the left and right running gears 3 on the vehicle body frame 10, thus reducing the rolling motion of the vehicle body 2. Therefore, driving stability is further improved.

[0107] (Item 3) The work vehicle 1 according to Item 1 or Item 2, wherein the running gear 3 includes a front running gear 3F located at the front of the vehicle frame 10 and a rear running gear 3R located at the rear of the vehicle frame 10, and the battery unit 8 is located above the front running gear 3F on the vehicle frame 10.

[0108] According to the work vehicle 1 related to item 3, the battery unit 8 is supported above the front running gear 3F on the vehicle frame 10, thus further improving driving stability.

[0109] (Item 4) The work vehicle 1 according to any one of items 1 to 3, wherein the battery unit 8 comprises a battery module 8A and a cooling device 81 for cooling the battery module 8A, the battery module 8A is incorporated into the central unit 8C, and the cooling device 81 is incorporated into one of the first side units, the left unit 8L and the right unit 8R.

[0110] According to the work vehicle 1 related to item 4, by incorporating the heavy battery module 8A into the central unit 8C, the center of gravity of the entire vehicle can be set lower, and the rolling motion of the vehicle body 2 can also be reduced. Therefore, driving stability is further improved. Moreover, in this vehicle, the battery module 8A can be forcibly cooled by the cooling device 81 incorporated in the left unit 8L or the right unit 8R, so that the high charging performance of the battery unit 8 can also be maintained.

[0111] (Item 5) The work vehicle 1 according to Item 4, which is equipped with an electrical component E1, wherein the electrical component E1 is incorporated into the second side unit, which is different from the first side unit, of the left unit 8L and the right unit 8R.

[0112] In the work vehicle 1 related to item 5, the cooling device 81 for the battery module 8A is housed in one of the left unit 8L and right unit 8R of the battery unit 8, and the electrical component E1 is housed on the opposite side. Therefore, the electrical component E1 is less affected by the heat generated from the battery module 8A. Consequently, the operational stability of the electrical component E1 is also improved.

[0113] (Item 6) The work vehicle 1 according to Item 4 or 5, wherein the cooling device 81 comprises a cooling duct 84 that constitutes a circulation path for the internal air of the central unit 8C, a circulation fan 85 that circulates the internal air between the central unit 8C and the cooling duct 84, and an external heat sink 86 provided on the outside of the cooling duct 84 for cooling the cooling duct 84.

[0114] According to the work vehicle 1 related to item 6, the internal air of the central unit 8C, which contains heat generated from the battery module 8A, is sent into the cooling duct 84 by the circulation fan 85, cooled by heat exchange between the cooling duct 84 and the external heat sink 86, and then returned to the inside of the central unit 8C. As a result, the battery module 8A is always forcibly cooled to below a certain temperature, thereby maintaining the high charging performance of the battery unit 8.

[0115] (Item 7) The work vehicle 1 described in Item 6, wherein the external heat sink 86 cools the cooling duct by heat exchange with the outside air of the battery unit 8.

[0116] According to the work vehicle 1 related to item 7, since there is no need for piping to circulate a refrigerant, as in a liquid-cooled heat exchanger, the battery module 8A can be efficiently cooled even in a relatively narrow space such as the inside of the front hood 15A. Therefore, the high charging performance of the battery unit 8 can be maintained.

[0117] (Item 8) The work vehicle 1 according to Item 6 or Item 7, wherein the cooling device 81 is provided inside the cooling duct 84 and has an internal heat sink 87 that cools the internal air by heat exchange with the cooling duct 84.

[0118] According to the work vehicle 1 related to item 8, the internal air of the central unit 8C, which contains heat generated from the battery module 8A, is sent into the cooling duct 84 by the circulation fan 85, cooled by heat exchange with the outside air of the battery unit 8 via the internal heat sink 87, the cooling duct 84, and the external heat sink 86, and then returned to the inside of the central unit 8C. As a result, the battery module 8A is cooled more efficiently. Therefore, the high charging performance of the battery unit 8 can be maintained.

[0119] (Item 9) The work vehicle 1 according to any one of items 6 to 8, wherein the cooling device 81 has a cooling fan 88 that supplies external air from the battery unit 8 to the external heat sink 86.

[0120] According to the work vehicle 1 related to item 9, external air from the battery unit 8 can be forcibly supplied to the external heat sink 86, so the battery module 8A is cooled more efficiently. Therefore, the high charging performance of the battery unit 8 can be maintained.

[0121] (Item 10) The work vehicle 1 according to any one of items 6 to 9, wherein the battery unit 8 has a warm air passage F1 that guides the internal air that has passed through the battery module 8A into the inside of the cooling duct 84, and a cold air passage F2 that guides the internal air that has passed through the inside of the cooling duct 84 back to the battery module 8A.

[0122] According to the work vehicle 1 related to item 10, when the air passes through the battery module 8A, the air that has recovered heat from the battery module 8A is sent into the cooling duct 84 through the warm air passage F1. Furthermore, when the air passes through the cooling duct 84, the air that has been cooled by heat exchange in the cooling duct 84 is guided to the vicinity of the battery module 8A through the cold air passage F2. As a result, the battery module 8A is cooled more efficiently. Therefore, the high charging performance of the battery unit 8 can be maintained.

[0123] (Item 11) The work vehicle 1 according to Item 10, wherein the battery module 8A includes a first battery module BM1 and a second battery module BM2 arranged side by side inside the central unit 8C, the warm air passage F1 is provided on the opposing surfaces of the first battery module BM1 and the second battery module BM2, and the cold air passage F2 is provided on the outer surface of the first battery module BM1 opposite to the second battery module BM2, and on the outer surface of the second battery module BM2 opposite to the first battery module BM1.

[0124] According to the work vehicle 1 related to item 11, the air (hot air) from which heat has been recovered from the first battery module BM1 and the second battery module BM2 is collected in a warm air passage F1 provided between the opposing surfaces of the first battery module BM1 and the second battery module BM2 and guided to a cooling duct 84. This prevents the entire battery unit 8 from being heated by the hot air.

[0125] On the other hand, the air (cold air) that has released heat to the outside through the cooling duct 84 is guided to the first battery module BM1 and the second battery module BM2, respectively, through a cold air passage F2 provided on the outer surface opposite to the opposing surface of the first battery module BM1 and the second battery module BM2. In this way, the battery unit 8 according to item 11 circulates the air (hot air) that has recovered heat from both modules BM1 and BM2 in a flow that allows for natural convection from the opposing surface side to the outer surface side of the two modules BM1 and BM2, making it possible to cool the hot air more efficiently within the cooling duct 84. Therefore, the high charging performance of the battery unit 8 can be maintained.

[0126] (Item 12) The work vehicle 1 described in Item 11 is provided with the circulation fan 85 in the cold air passage F2.

[0127] If the fan motor of the circulation fan 85 is exposed to hot air and becomes hot, there is a risk that the motor performance will deteriorate, affecting the cooling performance of the battery module 8A. However, according to the work vehicle 1 related to item 12, since the circulation fan 85 is installed in the cold air passage F2, it can stably supply the air cooled by the cooling duct 84 into the interior of the central unit 8C. As a result, the battery module 8A is always forcibly cooled to below a certain temperature, so that the high charging performance of the battery unit 8 can be maintained.

[0128] Having described the present invention above, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope of equivalents of the claims are intended to be included.

[0129] 1. Work vehicle 2. Body 3. Running gear 3F Front wheels (front running gear) 3R Rear wheels (rear running gear) 5. Electric motor 5A First motor 5B Second motor 5C Third motor 6. Hydrogen tank 7. Fuel cell unit (fuel cell) 8. Battery unit 9. Hydraulic pump (hydraulic system) 12. Transmission case (casing) 20. Power transmission system 90. Control device U1. Work device

Claims

1. A work vehicle comprising: a vehicle frame; a running device that supports the vehicle frame so that it can move; and a battery unit, wherein the vehicle frame has a left frame that constitutes the left side of the vehicle frame; and a right frame that is arranged side by side with a predetermined distance between it and the left frame and constitutes the right side of the vehicle frame; and the battery unit has a central unit located within the distance between the left frame and the right frame; a left unit connected to the central unit and located above the left frame; and a right unit connected to the central unit and located above the right frame.

2. The work vehicle according to claim 1, wherein the running gear includes a left running gear disposed on the left side of the left frame and a right running gear disposed on the right side of the right frame, and the battery unit is located between the left running gear and the right running gear in the vehicle body frame.

3. The work vehicle according to claim 1, wherein the running gear includes a front running gear disposed at the front of the vehicle frame and a rear running gear disposed at the rear of the vehicle frame, and the battery unit is located above the front running gear on the vehicle frame.

4. The work vehicle according to any one of claims 1 to 3, wherein the battery unit comprises a battery module and a cooling device for cooling the battery module, the battery module is incorporated into the central unit, and the cooling device is incorporated into one of the first side units, the left unit and the right unit.

5. The work vehicle according to claim 4, wherein the work vehicle is equipped with electrical components, and the electrical components are incorporated into the second side unit, which is different from the first side unit, among the left unit and the right unit.

6. The work vehicle according to claim 4, wherein the cooling device comprises a cooling duct that constitutes a circulation path for internal air of the central unit, a circulation fan that circulates the internal air between the central unit and the cooling duct, and an external heat sink provided on the outside of the cooling duct for cooling the cooling duct.

7. The work vehicle according to claim 6, wherein the external heat sink cools the cooling duct by heat exchange with the outside air of the battery unit.

8. The work vehicle according to claim 6, wherein the cooling device is provided inside the cooling duct and has an internal heat sink that cools the internal air by heat exchange with the cooling duct.

9. The work vehicle according to claim 6, wherein the cooling device has a cooling fan that supplies external air from the battery unit to the external heat sink.

10. The work vehicle according to claim 6, wherein the battery unit has a warm air passage that guides the internal air that has passed through the battery module into the cooling duct, and a cold air passage that guides the internal air that has passed through the cooling duct to the battery module.

11. The work vehicle according to claim 10, wherein the battery module includes a first battery module and a second battery module arranged side by side inside the central unit, the warm air passage is provided on the opposing surfaces of the first battery module and the second battery module, and the cold air passage is provided on the outer surface of the first battery module opposite to the second battery module, and on the outer surface of the second battery module opposite to the first battery module.

12. The work vehicle according to claim 11, wherein the circulation fan is provided in the cold air passage.

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