Work machine, work vehicle, and tank unit

Abstract

This work machine comprises: a vehicle body capable of traveling; a tank 13 mounted on the vehicle body; a fuel cell 24 mounted on the vehicle body and generating power with hydrogen supplied from the tank 13; a valve 60 capable of blocking supply of hydrogen from the tank 13 to the fuel cell 24; and a detection device 80 provided in the vehicle body. The vehicle body travels on the basis of detection information from the detection device 80, and the valve 60 is closed when it is determined that a travel state of the vehicle body obtained from the detection information is dangerous.

Description

Work machines, work vehicles, and tank units

[0001] The present invention relates to a work machine, a work vehicle, and a tank unit. This application claims priority to Japanese Application No. 2023-219114, filed December 26, 2023, and incorporates the entire contents of said Japanese application by reference. This application claims priority to Japanese Application No. 2023-219244, filed December 26, 2023, and incorporates the entire contents of said Japanese application by reference.

[0002] From the viewpoint of environmental protection, a work machine has been proposed that is equipped with a fuel cell and driven by a motor that rotates using electricity generated by the fuel cell (see, for example, Patent Document 1). Hydrogen is used as fuel for the fuel cell. The work machine disclosed in Patent Document 1 is a tractor, and a tank is mounted on the vehicle body.

[0003] Patent Document 2 describes a fuel cell system that includes a hydrogen tank that supplies hydrogen to a fuel cell, a main stop valve that is provided in the hydrogen tank and opens and closes to switch between supplying and stopping hydrogen, and an atmospheric pressure sensor that measures atmospheric pressure to control the supply of hydrogen to the fuel cell. The fuel cell system in Patent Document 2 detects a collision with the vehicle from the measurement results of the atmospheric pressure sensor when the drive wheels are locked and the main stop valve is open, and if a collision is detected, control is executed to close the main stop valve.

[0004] JP 2023-13186 A JP 2017-54711 A

[0005] A work machine according to one embodiment of the present invention comprises a vehicle body capable of running, a tank mounted on the vehicle body, a fuel cell mounted on the vehicle body that generates electricity using hydrogen supplied from the tank, a valve capable of cutting off the supply of hydrogen from the tank to the fuel cell, and a detection device provided on the vehicle body, wherein the vehicle body runs based on detection information from the detection device, and the valve is closed when the running conditions of the vehicle body obtained from the detection information are determined to be dangerous.

[0006] A work vehicle according to one embodiment of the present invention is a work vehicle comprising a vehicle body, a fuel cell mounted on the vehicle body, and a tank unit having a tank capable of storing fuel, wherein the tank unit has a casing that houses the tank and an impact sensor that can detect an impact applied to the casing.

[0007] A tank unit according to one embodiment of the present invention is a tank unit installed in a work vehicle whose driving source is a fuel cell, and includes a tank that can be filled with fuel to be supplied to the fuel cell, a casing that houses the tank, and an impact sensor that can detect impacts applied to the casing.

[0008] FIG. 1 is a perspective view showing an example of the overall structure of a work machine in Chapter 1. FIG. 2 is a right side view of the work machine in Chapter 1 with some of the exterior parts removed. FIG. 3 is a perspective view showing an example of the internal structure of a work vehicle in Chapter 1. FIG. 4 is a block diagram showing a portion of the functional configuration of the work vehicle in Chapter 1. FIG. 5 is a flow diagram explaining the operation of the work vehicle in Chapter 1. FIG. 6 is an explanatory diagram showing the work vehicle in Chapter 1 traveling on a road by autonomous driving. FIG. 7 is an explanatory diagram of a target route when autonomous driving is performed in a field in Chapter 1. FIG. 8 is a flowchart showing an example of control for autonomous driving in Chapter 1. FIG. 9 is an explanatory diagram of the work vehicle traveling by autonomous driving in Chapter 1. FIG. 10 is a perspective view of the work vehicle in Chapter 2. FIG. 11 is a right side view of the work vehicle in Chapter 2 with some of the exterior parts removed. FIG. 12 is a perspective view showing an example of the internal structure of a work vehicle in Chapter 2. FIG. 13 is a block diagram showing an example of the functional configuration of a work vehicle in Chapter 2. Fig. 14 is a block diagram showing an example of the internal configuration of the tank unit in Chapter 2. Fig. 15 is an explanatory diagram showing an example of the towing type work vehicle in Chapter 2.

[0009] <Chapter 1> <Problem to be Solved by the Present Invention> In work machines such as those described above, measures to prevent leakage of the hydrogen fuel are considered essential not only during normal operation of the work machine, but also in dangerous situations such as when the work machine collides with an obstacle or rolls over on an access road to a work site such as a farm field. Therefore, the present disclosure provides a work machine that can prevent leakage of hydrogen gas in dangerous situations.

[0010] <Effects of the Present Disclosure> According to the work machine of the present disclosure, it is possible to prevent hydrogen gas leakage in an emergency.

[0011] <Outline of Embodiments of the Present Disclosure> Below, an outline of embodiments of the present disclosure will be listed and described. (1) A work machine of this embodiment has a vehicle body that is capable of traveling, a tank mounted on the vehicle body, a fuel cell, a valve that is capable of blocking a supply path from the tank to the fuel cell, and a detection device provided on the vehicle body, the vehicle body traveling based on detection information from the detection device, and the valve being closed when the traveling condition of the vehicle body obtained from the detection information is determined to be dangerous.

[0012] According to the above-described working machine, as the vehicle body travels based on the detection information from the detection device, the detection information detected by the detection device is used to determine whether the traveling conditions of the vehicle body are dangerous. If the conditions are dangerous, the valve is closed, the supply of hydrogen gas from the tank is cut off, and hydrogen gas leakage is prevented.

[0013] (2) In the work machine of (1), the detection device can detect obstacles around the vehicle body, and the vehicle body takes action to avoid the obstacle or stop traveling if the position of the obstacle detected by the detection device is within a predetermined distance from the vehicle body, and the valve is closed when the position of the obstacle is within the predetermined distance from the vehicle body, indicating that the traveling situation is dangerous. With this configuration, the detection device detects surrounding obstacles while the work machine is traveling. If there is a possibility of collision with the obstacle, the valve is closed. It becomes possible to cut off the supply of hydrogen gas from the tank before a collision occurs.

[0014] (3) In the work machine of (1) or (2), the detection device includes at least one of a LiDAR sensor, a millimeter-wave radar, and an ultrasonic sensor, and the valve is closed based on the detection information detected by at least one of the LiDAR sensor, the millimeter-wave radar, and the ultrasonic sensor.

[0015] (4) In the construction machine according to any one of (1) to (3), when a signal is received from an operating device operated by a user, the valve switches from a closed state to an open state. According to this configuration, when the safety of the work vehicle is confirmed, the construction machine can be restored to the state it was in before it was determined to be dangerous, based on the operation of the user.

[0016] (5) In the work machine of (4) above, when the valve switches from a closed state to an open state, the vehicle body stops the operation to avoid the obstacle or the operation to stop traveling. According to this configuration, when the safety of the work vehicle is confirmed, the work machine can be returned to the state before it was determined to be dangerous based on the operation of the user.

[0017] (6) In the work machine of any one of (1) to (5), a tank unit is provided which has the tank and a support member that supports the tank, and the valve is provided in the tank unit.

[0018] <Details of Embodiments of the Present Disclosure> Hereinafter, details of embodiments of the present disclosure will be described with reference to the drawings. Note that at least some of the embodiments described below may be combined in any manner.

[0019] [Overall Structure of Work Machine] Figure 1 is a perspective view showing an example of the overall structure of a work machine. Figure 2 is a right side view of the work machine with some exterior parts (bonnet 34, cover 111, etc.) removed. The work machine of this embodiment is a work vehicle used for agricultural work, and more specifically, a tractor. The work machine is not limited to tractors, and may be a mobile body such as a construction machine or a utility vehicle. Below, a case will be described in which the work machine is a work vehicle (tractor) 10.

[0020] The directions of the work vehicle 10 are defined. The work vehicle 10 has a driver's seat 15. The front-rear, left-right, and up-down directions of the work vehicle 10 are defined based on the driver seated in the driver's seat 15. In other words, the direction forward for the driver is "front," and the direction behind is "rear." The right direction for the driver is "right," and the left direction is "left." The front-rear and left-right directions are parallel to the ground, and are perpendicular to the front-rear and left-right directions. The up-down direction is perpendicular to both the front-rear and left-right directions.

[0021] The left-right direction may be referred to as the "vehicle width direction." The forward direction is the "traveling direction" of the work vehicle 10. If the work vehicle 10 does not have a driver's seat 15, the direction in which work proceeds on the work vehicle 10 is the "forward," and the opposite direction is the "rear." Facing the direction in which work proceeds, the right side of the work vehicle 10 is the "right," and the left side is the "left."

[0022] The work vehicle 10 has a vehicle body 11 which has a chassis 41, a drive unit 14, a steering unit 39, a driver's seat 15, and a cabin 16. The vehicle body 11 further has a hood 34, a cover 111, a tank unit 21, a first radiator 48, and a second radiator 49.

[0023] The cabin 16 has front pillars, rear pillars, and a roof, and is a driver's compartment defined by these. The work vehicle 10 may have a canopy or roofing instead of the cabin 16. If the work vehicle 10 does not have a cabin 16, the tank unit 21 is disposed above the driver's seat 15 by the mounting frame 17.

[0024] 2, a first radiator 48, a fuel cell 24, and a second radiator 49 are mounted in this order from front to rear on the front part of the chassis 41. The first radiator 48 and the fuel cell 24 are covered by the hood 34, and the second radiator 49 is covered by a cover 111.

[0025] The tank unit 21 (see FIG. 2 ) has a tank 13 therein that stores fuel. The fuel is liquid or gas, such as hydrogen, methane, or carbon monoxide (CO). In this embodiment, the tank 13 stores hydrogen gas. The tank unit 21 of this embodiment has multiple tanks 13. The drive device 14 is driven by the stored fuel. The work vehicle 10 is a fuel cell vehicle (FCV), and runs on electricity generated by a chemical reaction between hydrogen and oxygen in a fuel cell 24 as its energy source.

[0026] The tank unit 21 has a support member 211 that supports the tank 13. A safety valve 60 (described later) is provided in the tank unit 21. The safety valve 60 can cut off the supply of hydrogen from the tank 13 to the fuel cell 24.

[0027] The drive device 14 has a fuel cell 24, a battery unit 30, and a motor 31 (see FIG. 3). FIG. 3 is a perspective view showing an example of the internal structure of the work vehicle 10. The battery unit 30 has a battery pack (battery) that stores the power generated by the fuel cell 24. The work vehicle 10 has a hydrogen gas pipe 22. Hydrogen gas is supplied from a fill port 42 (see FIG. 4) connected to the end of the pipe 22 and filled into each tank 13. The hydrogen gas in the tank 13 is supplied to the fuel cell 24 through the pipe 22.

[0028] The steering device 39 (see FIG. 2) has a steering shaft that is rotated by a steering wheel 39A. The steering device 39 changes the rolling direction of the wheels (front wheels 12A) and changes the traveling direction of the work vehicle 10. The steering device 39 has an assist mechanism (power steering device). The assist mechanism uses hydraulics or electricity to assist the driver's operating force on the steering wheel 39A. When the work vehicle is driven automatically, the assist mechanism is used to perform steering and change the traveling direction under the control of a control device 70 (see FIG. 4).

[0029] The travelling device 12 of the work vehicle 10 has front wheels 12A and rear wheels 12B. One or both of the front wheels 12A and the rear wheels 12B rotate by the power of a motor 31. One or both of the wheels 12A, 12B (drive wheels) that rotate by the power of the motor 31 may be crawlers (crawlers). The travelling device 12 enables the vehicle body 11 to travel.

[0030] [Internal Structure of Work Vehicle] As shown in Figure 3, the chassis 41 is configured with a steel frame that is long in the front-to-rear direction, and has a front frame 32 and a gear case 33. The gear case 33 is connected to the rear of the front frame 32. The gear case 33 and the front frame 32 form the framework of the vehicle body 11. The chassis 41 is a vehicle body frame on which the drive unit 14, driver's seat 15, cabin 16, tank 13, fuel cell 24, etc. are mounted.

[0031] A mounting frame 17 for the tank unit 21 is connected to the chassis 41. The mounting frame 17 supports the tank unit 21 above the cabin 16. The mounting frame 17 includes a substantially rectangular ceiling frame 17A that is longer in the front-to-rear direction than in the left-to-right direction, a plurality of pillars 17B that support the ceiling frame 17A from below, and a pair of left and right reinforcing frames 17C that are connected to the front end of the ceiling frame 17A. The tank unit 21 is connected to the ceiling frame 17A.

[0032] A support frame 37 is connected to the chassis 41, and the battery unit 30 is supported on the vehicle body 11 by the support frame 37. A gear case 33 located behind the motor 31 has a power transmission mechanism therein. The power transmission mechanism includes a transmission, a clutch, and a differential gear, and transmits the rotation of the output shaft of the motor 31 to the traveling device 12 by slowing or accelerating the rotation. The power transmission mechanism inside the gear case 33 includes a branching mechanism that outputs a portion of the power of the motor 31 to a PTO shaft 334 (see FIG. 2 ). The PTO shaft 334 is an output shaft that protrudes from the rear of the gear case 33.

[0033] The work vehicle 10 has a coupling device 43 (see FIG. 2 ) for coupling a work implement to the rear of the vehicle body 11 to perform the desired agricultural work. The work implement is also called an implement. Examples of work implements include cultivators and balers. The rotational motion of the PTO shaft 334 is transmitted to the input shaft of the work implement, for example, while the work vehicle 10 is traveling. The work vehicle 10 can drive the work implement with the power of the motor 31 while traveling in a field or the like.

[0034] [Regarding the detection device 80] Figure 4 is a block diagram showing part of the functional configuration of the work vehicle 10. The work vehicle 10 has a detection device 80 that detects the situation around the vehicle body 11, i.e., the driving situation. The detection device 80 is provided on the vehicle body 11. The work vehicle 10 includes, as the detection device 80, at least one of a camera 81, a LiDAR (Light Detection and Ranging) sensor 82, a microphone sensor 83, a millimeter-wave radar 84, and an ultrasonic sensor 85. A signal acquired by the detection device 80 is transmitted to the control device 70.

[0035] The cameras 81 are provided, for example, on the front, rear, left and right sides of the work vehicle 10, and capture images of the environment around the work vehicle 10. The cameras 81 are, for example, CCD cameras equipped with CCD image sensors, or CMOS cameras equipped with CMOS image sensors. The cameras 81 have a processing circuit that processes signals output from the image sensors, and the processing circuit acquires image information of the surroundings as detection information. The cameras 81, which are detection devices 80, are capable of detecting obstacles around the vehicle body 11.

[0036] The LiDAR sensor 82 is a three-dimensional range sensor. The LiDAR sensor 82 is disposed, for example, at the lower front portion of the vehicle body 11. The LiDAR sensor 82 acquires and outputs sensor data indicating the distance and direction of each measurement point on a surrounding object, and sensor data indicating the two-dimensional or three-dimensional coordinate values ​​of each measurement point on a surrounding object. The detection information (sensor data) of the LiDAR sensor 82 is used to detect surrounding obstacles. In other words, the LiDAR sensor 82, which is the detection device 80, can detect obstacles around the vehicle body 11.

[0037] The microphone sensor 83, millimeter wave radar 84, and ultrasonic sensor 85 are provided, for example, on the front, back, left, and right sides of the work vehicle 10, and can detect obstacles around the vehicle body 11 without contact using sound waves, millimeter waves, and ultrasonic waves.

[0038] The work vehicle 10 may have an inertial measurement unit 77 as the detection device 80. The inertial measurement unit 77 has one or both of a three-axis gyro sensor and a three-directional acceleration sensor. The detection signal from the inertial measurement unit 77 can detect at least one of the attitude, such as tilt, of the work vehicle 10 (vehicle body 11), vibration due to a collision or the like, and acceleration (acceleration / deceleration). The signal acquired by the inertial measurement unit 77 is sent to the control device 70.

[0039] As described above, the detection device 80 including at least one of the camera 81, the LiDAR sensor 82, the microphone sensor 83, the millimeter-wave radar 84, and the ultrasonic sensor 85 can detect obstacles around the vehicle body 11 as the traveling condition (surrounding condition) of the vehicle body 11. The inertial measurement unit 77 can detect at least one of the attitude, vibration, and acceleration of the vehicle body 11 as the traveling condition of the vehicle body 11.

[0040] The control device 70 is capable of executing a driving control for controlling the driving of the vehicle body 11, a determination process for estimating danger (abnormality) of the vehicle body 11 based on the detection information of the detection device 80, and a valve control process for executing control to close a safety valve 60 (described later) when danger is estimated by the determination process. Note that danger (abnormality) of the vehicle body 11 refers to, for example, when the vehicle body 11 collides with an obstacle, when the vehicle body 11 is about to collide with an obstacle, when the vehicle body 11 rolls over, or when the vehicle body 11 is about to roll over.

[0041] The work vehicle 10 has a positioning device 76. The positioning device 76 receives satellite signals transmitted from a plurality of GNSS satellites and performs positioning based on the satellite signals. GNSS is a general term for satellite positioning systems such as GPS (Global Positioning System), QZSS (Quasi-Zenith Satellite System: for example, "Michibiki"), GLONASS (Russia), Galileo (Europe), and BeiDou (China).

[0042] The positioning device 76 has a receiver that receives satellite signals, and a processor (arithmetic processing unit). The receiver has an antenna that receives signals from GNSS satellites. The processor calculates and determines the position (coordinates) of the work vehicle 10 based on the signals received by the antenna. Information indicating the position of the work vehicle 10 is transmitted to the control device 70 and used for automatic driving, etc.

[0043] [Regarding Driving Modes of Work Vehicle 10] The work vehicle 10 of this embodiment has the function of executing both a manual driving mode operated by a driver and an automatic driving mode not operated by a driver. The work vehicle 10 is capable of automatic driving and manual driving both within a field or other work site and on roads (farm roads) outside the field.

[0044] Manual driving is driving in which the operation (including driving) of the work vehicle 10 is performed by manual operation of a driver seated in the driver's seat 15 of the work vehicle 10. Automatic driving is driving in which the operation (including driving) of the work vehicle 10 is performed by the functions of a control device 70 that the work vehicle 10 has, without manual operation by the driver.

[0045] Autonomous driving is realized by the functions of the driving control unit 701 (described later) possessed by the control device 70. The control device 70 can control at least one of the steering required for the movement of the work vehicle 10, adjustment of the movement speed, and starting and stopping of movement. In the case of autonomous driving, in addition to the driving control of the work vehicle 10, the operation control of the work implement is also performed without the driver's operation. In other words, the work vehicle 10 drives automatically, while the work implement performs work automatically.

[0046] As described above, the work vehicle 10 has a positioning device 76. The control device 70 (travel control unit 701) causes the work vehicle 10 to travel automatically based on the position of the work vehicle 10 identified by the positioning device 76 and a target route that is pre-stored in the storage device of the control device 70.

[0047] Autonomous driving includes cases where the work vehicle 10 travels autonomously while sensing the surrounding environment using the detection device 80, without human involvement in controlling the movement of the work vehicle 10. Autonomous driving includes not only movement of the work vehicle 10 toward a destination along a predetermined route (the target route), but also movement of the work vehicle 10 following a tracking target. During such autonomous driving, obstacles are detected and avoidance driving is performed to avoid the obstacles.

[0048] The work vehicle 10 can also be driven remotely by someone other than the driver seated in the driver's seat 15. For this purpose, the work vehicle 10 has a communication device (not shown). The work vehicle 10 is remotely controlled by using wireless communication between the work vehicle 10 and a management computer at the management center. The detection information from the detection device 80 is also used when the work vehicle 10 is driven remotely.

[0049] [Regarding the Fuel System and Control System of the Work Vehicle 10] As shown in Figure 4, the work vehicle 10 has a fuel system FS and a control system SS. Components of the fuel system FS include the tank 13, the valve unit 45, and the safety valve 60. Components of the control system SS include a control device 70, a positioning device 76, a detection device 80, and an operation device 73. The operation device 73 is installed, for example, in the cabin 16, and is a device that includes buttons and the like that are operated by a user (such as the driver of the work vehicle 10, a worker, or a farmer).

[0050] The fuel system FS will now be described. The tank 13 is connected to a first pipe 22A and a second pipe 22B via a valve unit 45. The first pipe 22A is a gas pipe connecting the fill port 42 and the valve unit 45, and guides hydrogen gas introduced into the fill port 42 to the tank 13. The second pipe 22B is a gas pipe connecting the fuel cell 24 and the valve unit 45, and guides hydrogen gas stored in the tank 13 to the fuel cell 24.

[0051] The valve unit 45 is an assembly of valves including an on-off valve and a pressure reducing valve. By controlling the operation of the internal valves, the valve unit 45 adjusts the flow rate of hydrogen gas in the tank 13 and outputs it to the fuel cell 24. Hydrogen pipes 22C are provided between the valve unit 45 and each tank 13.

[0052] The safety valve 60 is in an open state during normal driving. When the safety valve 60 is in a closed state, it can cut off the supply of hydrogen from the tank 13 to the fuel cell 24. The safety valve 60 is closed when the driving conditions of the vehicle body 11 are determined to be dangerous. The safety valve 60 may be provided in the valve unit 45, but in this embodiment, it is provided in a nozzle portion 131 of the tank 13. The nozzle portion 131 is part of the tank 13 and is the connection portion of the tank to which the hydrogen pipe 22C is connected.

[0053] One safety valve 60 is provided for each tank 13. The safety valve 60 is an electromagnetic valve that opens and closes based on a control signal from the control device 70 (valve control unit 703). The safety valve 60 is configured to close when the power supply to the safety valve 60 is cut off. When the work vehicle 10 is in a normal driving state, power is supplied to the safety valve 60 and it is in an open state. When the state (driving situation) of the work vehicle 10 becomes dangerous, the control device 70 cuts off the power supply to the safety valve 60.

[0054] By providing the safety valve 60 in the nozzle portion 131, it is possible to prevent hydrogen from leaking from the tank 13 even if, for example, the work vehicle 10 collides with an obstacle or falls over, causing damage along the line connecting the tank 13 and the fuel cell 24 (first line 22A, second line 22B, and hydrogen line 22C).

[0055] As described above, the work vehicle 10 has a detection device 80 provided on the vehicle body 11. The work vehicle 10 includes, as the detection device 80, at least one of a camera 81, a LiDAR sensor 82, a microphone sensor 83, a millimeter-wave radar 84, and an ultrasonic sensor 85. Each of the detection devices 80 is capable of detecting obstacles around the vehicle body 11.

[0056] The detection information (sensor data) by the detection device 80 is transmitted to the control device 70. The control device 70 uses the detection information to detect obstacles around the work vehicle 10. As the vehicle body 11 travels (autonomously drives) based on the detection information from the detection device 80, the control device 70 can use the detection information detected by the detection device 80 to determine whether the driving conditions of the vehicle body 11 are dangerous. If it is determined to be dangerous, the safety valve 60 is closed. Furthermore, in this embodiment, if it is determined to be dangerous, an operation to avoid the obstacle or an operation to stop driving is performed. If the work vehicle 10 is driving autonomously, it will continue driving to automatically detour around the obstacle, or will stop driving by stopping autonomous driving.

[0057] [Regarding the system configuration of the work vehicle 10] The control device 70 is configured from a control unit (computer) including a processor (arithmetic processing device) and memory consisting of RAM, ROM, etc. The processor reads and executes a computer program from the memory, thereby performing each function of the control device 70. The control device 70 may be configured from one control unit (ECU: Electronic Control Unit) or from multiple control units. When the control device 70 is configured from multiple control units, information can be communicated between these control units.

[0058] The control device 70 includes a storage device such as a nonvolatile memory that stores various types of information. Various computer programs for causing the control units to function are stored in the storage device. Map information that can be used for autonomous driving is also stored in the storage device. In this embodiment, the control device 70 includes a cruise control unit 701, a determination unit 702, and a valve control unit 703 as functional units obtained by the processor executing the computer programs.

[0059] The driving control unit 701 executes control related to the driving of the vehicle main body 11. Specifically, the driving control unit 701 performs overall control related to the driving, including the automatic driving, of the work vehicle 10. The driving control unit 701 is capable of performing control related to automatic driving. Specific examples of automatic driving will be described later.

[0060] The driving control unit 701 can also perform control to make the vehicle body 11 detour around obstacles that exist around the work vehicle 10, or control to stop the vehicle body 11. The driving control unit 701 intervenes in the avoidance driving and driving stop during any of automatic driving, remote driving, and manual driving.

[0061] The determination unit 702 estimates danger (abnormality) of the vehicle body 11 based on the detection information of the detection device 80. If the detection device 80 is a camera 81 or a LiDAR sensor 82, the detection device 80 acquires the distance from the vehicle body 11 to the position of an obstacle. The determination unit 702 acquires information on this distance (detection distance) as detection information. If the detection distance is equal to or less than a predetermined distance, the determination unit 702 estimates that there is danger. If the detection distance exceeds the predetermined distance, the determination unit 702 estimates that there is no danger.

[0062] If the detection device 80 is a microphone sensor 83, a millimeter-wave radar 84, or an ultrasonic sensor 85, when the distance from the vehicle body 11 to the position of an obstacle becomes equal to or shorter than a predetermined distance, the detection device 80 outputs, as detection information, information indicating that the obstacle is in an approaching position (approach information). When the determination unit 702 acquires the approach information, it estimates that there is danger. When the determination unit 702 does not acquire the approach information, there is no danger.

[0063] When the determination unit 702 estimates that there is a danger, the valve control unit 703 executes control to close the safety valve 60. The valve control unit 703 can execute control to close the safety valve 60 before the vehicle body 11 collides or overturns, as well as when the vehicle body 11 collides or overturns.

[0064] [Operation of the Work Vehicle 10 in the Event of Danger] Figure 5 is a flow diagram illustrating the operation of the work vehicle 10. The fuel cell 24 of the work vehicle 10 receives a supply of hydrogen gas from the tank 13 and generates electricity (step S10). The motor 31 is driven by the power generated by the fuel cell 24, and the vehicle body 11 travels (step S20). In step S20, the vehicle body 11 travels based on detection information detected by the detection device 80. For example, the vehicle body 11 travels autonomously based on detection information from the detection devices 80, such as the camera 81 and LiDAR sensor 82.

[0065] Here, a case will be described in which the autonomously driving vehicle body 11 approaches an obstacle, such as a structure or a tree, on a road or in a field, resulting in a dangerous situation. The detection device 80 detects obstacles around the vehicle body 11 as the driving status of the vehicle body 11. The detection device 80 is always in a state of detecting the surrounding situation while driving (step S30). The detection device 80 is, for example, at least one of a camera 81, a LiDAR sensor 82, a millimeter-wave radar 84, an ultrasonic sensor 85, and a microphone sensor 83.

[0066] When an obstacle is detected by the detection device 80, the control device 70 calculates the distance between the obstacle and the vehicle body 11, and compares the calculated distance with a threshold value set in the control device 70. This comparison determines whether the traveling situation of the vehicle body 11 is dangerous (collision risk) or not (step S40).

[0067] If the distance between the obstacle detected by the detection device 80 and the vehicle body 11 is equal to or shorter than a predetermined distance ("Yes" in step S40), the vehicle body 11 executes an operation to avoid danger (step S50). That is, the vehicle body 11 executes an operation to avoid the obstacle. Or, it executes an operation to stop its traveling. Specifically, the traveling control unit 701 controls the steering device 39 to make the vehicle body 11 detour so as to avoid contact with the obstacle. Or, it controls one or both of the motor 31 and the gear case 33 to stop the traveling of the vehicle body 11.

[0068] Furthermore, if the distance between the obstacle and the vehicle body 11 is equal to or shorter than a predetermined distance (if "Yes" in step S40), the traveling conditions of the vehicle body 11 are determined to be dangerous, and the safety valve 60 is closed by the valve control unit 703 (step S60). That is, the power supply to the safety valve 60 is cut off. In this way, if the traveling conditions of the vehicle body 11 obtained from the detection information of the detection device 80 are determined to be dangerous, the safety valve 60 is closed as a precaution.

[0069] As described above, while the vehicle body 11 travels automatically based on the detection information of the detection device 80 (steps S20 and S30), the detection information detected by the detection device 80 is used to determine whether the traveling conditions of the vehicle body 11 are dangerous (step S40). If the traveling conditions are dangerous, the safety valve 60, which is open during normal traveling, is closed (step S60).

[0070] Here, a case will be described in which the autonomously driven vehicle body 11 is traveling on a road with an uneven slope, for example, and the traveling posture is disrupted, resulting in a dangerous situation, such as a risk of tipping over. The detection device 80 detects the posture of the vehicle body 11, i.e., the tilt angle of the vehicle body 11. To this end, the detection device 80 functioning here includes an inertial measurement unit 77 including a gyro sensor and / or an acceleration sensor, in addition to a camera 81 and a LiDAR sensor 82. When the vehicle body 11 is traveling on a flat surface, the tilt angle is zero. The more the vehicle body 11 tilts, the larger the tilt angle becomes.

[0071] The fuel cell 24 of the work vehicle 10 receives a supply of hydrogen gas from the tank 13 and generates electricity (step S10 in FIG. 5 ). The motor 31 is driven by the power generated by the fuel cell 24, and the vehicle body 11 travels (step S20). In step S20, the vehicle body 11 travels based on detection information detected by the detection device 80. For example, the vehicle body 11 travels in an autonomous driving mode based on detection information from the detection devices 80, such as the camera 81 and the LiDAR sensor 82.

[0072] The inertial measurement unit 77 (detection unit 80) detects at least one of the attitude, vibration, and acceleration of the vehicle body 11 as the traveling condition of the vehicle body 11. The inertial measurement unit 77 (detection unit 80) constantly detects the attitude, etc. of the vehicle body 11 while traveling (step S30).

[0073] When the tilt angle (posture) of the vehicle body 11 is detected, the control device 70 compares the tilt angle with a threshold value set in the control device 70. This comparison determines whether the traveling conditions of the vehicle body 11 are dangerous (whether the vehicle body 11 may fall over) (step S40).

[0074] If, for example, the vehicle body 11 tilts significantly while the vehicle body is traveling in autonomous driving and the possibility of tipping over is estimated (if "Yes" in step S40), the safety valve 60, which is open during normal traveling, is closed (step S60). In other words, the power supply to the safety valve 60 is cut off. Furthermore, the traveling control unit 701 controls one or both of the motor 31 and the gear case 33 to stop the traveling of the vehicle body 11 as a danger avoidance operation (step S50).

[0075] As described above, even if there is a possibility that the work vehicle 10 will collide with an obstacle or is about to tip over, the vehicle body 11 travels based on the detection information of the detection device 80 (steps S20 and S30), and the detection information detected by the detection device 80 is used to determine whether the vehicle body's traveling conditions are dangerous (step S40). If the traveling conditions are dangerous, the safety valve 60, which is normally open during traveling, is closed (step S60). This makes it possible to shut off the supply of hydrogen gas from the tank 13 in advance, thereby preventing hydrogen gas leakage.

[0076] The return operation of the safety valve 60 will now be described. Even if the determination unit 702 estimates a danger to the vehicle main body 11, if it subsequently determines that there is no danger based on the detection information from the detection device 80, the valve control unit 703 opens the safety valve 60, which was once in a closed state. For example, if it is determined that there is no possibility of danger by the work vehicle 10 performing an avoidance operation, that is, that there is no possibility of a collision, the valve control unit 703 returns the safety valve 60 to an open state. Alternatively, if the tilt angle subsequently decreases and it is determined that there is no possibility of tipping over, the valve control unit 703 returns the safety valve 60 to an open state.

[0077] Another example of the return operation of the safety valve 60 will now be described. As described above, the work vehicle 10 has an operation device 73 inside the cabin 16 that is operated by the user (the driver of the work vehicle 10) (see FIG. 4). The operation device 73 includes a return button. When the user confirms that the work vehicle 10 will not collide with an obstacle or tip over, the return button is operated.

[0078] When the reset button is operated ("Yes" in step S100 of FIG. 5), the operating device 73 outputs a signal for resetting to the control device 70 (travel control unit 701, valve control unit 703). When the control device 70 receives the signal for resetting from the operating device 73, the valve control unit 703 switches the safety valve 60 from a closed state to an open state (step S110). In other words, by supplying power to the safety valve 60, the safety valve 60 opens.

[0079] If the vehicle body 11 is already performing an operation to avoid an obstacle (step S50), when the safety valve 60 switches from a closed state to an open state (step S110), the vehicle body 11 stops the operation to avoid the obstacle (step S120). In other words, the avoidance operation is interrupted. In the case of autonomous driving, an operation to start autonomous driving is performed again (step S130). Alternatively, if the vehicle body 11 is already performing an operation to stop driving in order to avoid an obstacle (step S50), when the safety valve 60 switches from a closed state to an open state (step S110), the operation to stop driving is stopped (step S120). In other words, the vehicle enters a standby state in which driving can be resumed. In the case of autonomous driving, an operation to start autonomous driving is performed again (step S130).

[0080] In this way, when the driving control unit 701 receives a signal from the operation device 73 operated by the user (step S120), it can execute control to cancel the danger avoidance driving and return the vehicle body 11 to a state where it can normally drive. In other words, when safety is confirmed, the work vehicle 10 returns to the state it was in before it was determined to be dangerous, based on the user's operation.

[0081] As described above, the work vehicle 10 of this embodiment has a detection device 80 that detects the traveling status of the vehicle body 11. The control device 70 of the work vehicle 10 is capable of performing a traveling control process that executes control related to the traveling of the vehicle body 11, a determination process that estimates a danger (abnormality) in the vehicle body 11 based on information detected by the detection device 80, and a valve control process that executes control to close the safety valve 60 if a danger is estimated by the determination process.

[0082] The driving control process is executed by a driving control unit 701. The determination process is executed by a determination unit 702. The valve control process is executed by a valve control unit 703. The driving control unit 701 can control the autonomous driving of the vehicle body 11 based on information from sensor devices mounted on the vehicle body 11. In the present embodiment, the sensor devices are a camera 81 and a LiDAR sensor 82. The sensor devices (camera 81 and LiDAR sensor 82) for this autonomous driving function as the detection device 80 and output detection information to the determination unit 702.

[0083] The camera 81 and LiDAR sensor 82 (sensor device) used for autonomous driving detect surrounding obstacles and the vehicle state of the vehicle body 11 as the driving conditions of the vehicle body 11. The determination unit 702 estimates the risk to the vehicle body 11 based on the detection information from the sensor device consisting of the camera 81 and LiDAR sensor 82. In other words, for risk estimation, the sensor device for autonomous driving is utilized as the detection device 80. There is no need to provide a separate dedicated sensor for risk estimation.

[0084] The sensor device may include at least one of a camera 81, a LiDAR sensor 82, a millimeter-wave radar 84, an ultrasonic sensor 85, and a microphone sensor 83. The sensor device functioning as a detection device 80 is capable of detecting obstacles around the vehicle body 11 as the driving condition. As described above, when an obstacle is detected while the vehicle body 11 is driving in autonomous driving mode and the possibility of a collision with the obstacle is estimated, the safety valve 60 is closed and the supply of hydrogen gas from the tank 13 is cut off.

[0085] If the sensor device mounted on the vehicle body 11 includes one or both of a gyro sensor and an acceleration sensor, that is, if the sensor device is an inertial measurement unit 77, the sensor device (inertial measurement unit 77) functioning as the detection device 80 can detect at least one of the attitude, vibration, and acceleration of the vehicle body 11 as the driving condition. As described above, if, for example, the vehicle body 11 tilts significantly while the vehicle body is driving in autonomous driving and the possibility of tipping over is estimated, the safety valve 60 is closed and the supply of hydrogen gas from the tank 13 is cut off.

[0086] In this embodiment, when a danger is estimated by the determination unit 702, the driving control unit 701 can execute driving control (stopping driving and stopping automatic driving) to avoid the danger. When a danger is estimated, the supply of hydrogen from the tank 13 to the fuel cell 24 is cut off, and the work vehicle 10 can be brought to an emergency stop, for example, as a driving operation to avoid the danger. This makes it possible to avoid a collision with an obstacle, and to prevent the work vehicle 10 from tipping over even if it is about to do so.

[0087] [Autonomous Driving of Work Vehicle 10] A specific example of autonomous driving will be described. The work vehicle 10 requires a target route for autonomous driving. The target route is generated before autonomous driving begins. The target route is generated by the control device 70 possessed by the work vehicle 10. Alternatively, the target route may be generated by a computer in a management device other than the work vehicle 10. In this case, the work vehicle 10 acquires information about the target route via a communication device.

[0088] FIG. 6 is an explanatory diagram showing a work vehicle 10 traveling autonomously on a road 8 outside a field 7. When the work vehicle 10 travels autonomously on a road 8, the work vehicle 10 requires environmental map information. The environmental map is map information of the environment in which the work vehicle 10 travels, and includes map information such as the field 7 and the roads 8 for traveling between the fields 7. A target route G is generated based on the map information. In other words, when an arrival destination is set in the map information, a route from the current position of the work vehicle 10 to that destination is generated as the target route G. In the case of FIG. 6 , a target route G along the road 8 has been generated. Information about the target route G is stored, together with the map information, in a storage device provided in the control device 70.

[0089] FIG. 7 is an explanatory diagram of a target route G when autonomous driving is performed in a field 7. The field 7 includes a work area 7a where the work vehicle 10 will work, and a headland 7b located near the outer periphery of the field 7. Which areas of the field 7 correspond to the work area 7a and which correspond to the headland 7b is set by the user. The target route G in the field 7 includes multiple parallel main routes P1 and a turning route P2 connecting the two main routes P1. The main route P1 is located in the work area 7a, and the turning route P2 is located in the headland 74. Although the main route P1 shown in FIG. 7 is straight, the main route P1 may also include curved portions.

[0090] The distance between the dashed lines in FIG. 7 represents the working width of the work implement 50. The working width is set in advance and stored in the storage device of the control device 70. The user (driver) inputs the working width to the control device 70 by operating the operating device in the cabin 16. The working width may be automatically recognized and input to the control device 70 when the work implement 50 is connected to the work vehicle 10. The distance between adjacent main paths P1 is set to match the working width. The target path G is created so as to pass through (cover) the entire work area 7a. The work vehicle 10 automatically travels along the target path G, repeating round trips from the work start point S to the work end point G.

[0091] Once the target route G for the outside of the field 7 or the inside of the field 7 has been generated, automatic driving becomes possible. Figure 8 is a flowchart showing an example of control for automatic driving. The travel control unit 701 (see Figure 4) performs automatic steering by executing the processing of steps S201 to S205 shown in Figure 8 while the work vehicle 10 is traveling. The travel speed of the work vehicle 10 is maintained at a preset value, but may be automatically changed midway.

[0092] While the work vehicle 10 is traveling, the cruise control unit 701 acquires position information of the work vehicle 10 obtained by the positioning device 76 (step S201). The position information is information that indicates the current position of the work vehicle 10. The cruise control unit 701 calculates the deviation E between the current position of the work vehicle 10 and the target route G (step S202). Figure 9 is an explanatory diagram of a work vehicle 10 traveling by autonomous driving. The deviation E is the difference between the current position of the work vehicle 10 and the target route G, and is, for example, a distance. The cruise control unit 701 determines whether the deviation E exceeds a threshold value (step S203 in Figure 8).

[0093] If the deviation E exceeds the threshold value ("Yes" in step S203), the cruise control unit 701 outputs a command signal to the control unit of the steering device 39 (see FIG. 2) in order to reduce the deviation E. Upon receiving the command signal, the steering device 39 changes the steering angle (step S204). The steering angle is changed until the deviation E becomes equal to or less than the threshold value. If the deviation E is equal to or less than the threshold value in step S203, step S204 is skipped.

[0094] In this embodiment (see FIG. 9 ), the steering device 39 is controlled based on the deviation E between the current position of the work vehicle 10 and the target route G, but the control may also include a heading deviation. For example, the cruise control unit 701 determines whether the angular difference between the heading of the work vehicle 10 identified by one or both of the positioning device 76 and the inertial measurement unit 77 and the direction of the target route G exceeds a preset threshold. Note that this angular difference is the heading deviation. If the angular difference exceeds the threshold, the control parameters (e.g., steering angle) of the steering device 39 are changed in accordance with the deviation.

[0095] Step S205 in Fig. 8 is a step in which the driving control unit 701 determines whether or not it has received a command to end operation. A command to end operation is issued in the following cases, for example: 1) An administrator (user) issues a command to stop automatic driving, for example, by remote control; 2) The work vehicle 10 reaches the destination (end position).

[0096] If the driving control unit 701 does not receive the command to end the operation (if "No" in step S205), the driving control unit 701 returns to step S201 and executes the same process thereafter. The driving control unit 701 repeats the operations of steps S201 to S205 until it receives the command to end the operation.

[0097] As described above, if an obstacle is detected by detection device 80 at any step during the processing of steps S201 to S205 for autonomous driving, travel control unit 701 can execute avoidance travel to avoid the obstacle. In other words, while work vehicle 10 is traveling, camera 81, which is detection device 80, captures images of the surrounding environment, and LiDAR sensor 82, which is also detection device 80, senses surrounding objects. Based on the detection information from detection device 80, danger avoidance operation can be executed (step S50 in FIG. 5). Furthermore, safety valve 60 is closed (step S60 in FIG. 5).

[0098] [Others] The above-described embodiments are illustrative in all respects and are not limiting. The scope of the present invention is indicated by the claims, not by the above-described embodiments, and includes all modifications within the scope equivalent to the configurations described in the claims. The symbols used in Chapter 1 are used only in this Chapter and are unrelated to the symbols in other chapters.

[0099] [Explanation of symbols] 10 Work vehicle (work machine) 11 Vehicle body 13 Tank 21 Tank unit 24 Fuel cell 60 Safety valve (valve) 70 Control device 73 Operation device 80 Detection device 82 LiDAR sensor 84 Millimeter wave radar 85 Ultrasonic sensor 211 Support member

[0100] <Chapter 2> <Problems to be Solved by the Invention> In the fuel cell system of Patent Document 2, depending on the physical distance from the atmospheric pressure sensor to the hydrogen tank, it may not be possible to accurately detect an impact that occurs in the hydrogen tank. Also, in the fuel cell system of Patent Document 2, depending on the transmission distance of the control signal from the control device to the main stop valve, there is a possibility that the closing operation will be delayed due to a communication time lag.

[0101] In view of the above-mentioned conventional problems, a first object of the present disclosure is to provide a work vehicle or the like that can accurately detect an impact to a tank, and a second object of the present disclosure is to provide a work vehicle or the like that can reduce the delay between the impact detection and the valve closing operation.

[0102] Effect of the Present Disclosure According to the present disclosure, it is possible to provide a work vehicle etc. that can accurately detect an impact occurring to a tank. According to the present disclosure, it is possible to provide a work vehicle etc. that can reduce the delay from impact detection to the valve closing operation.

[0103] <Outline of Embodiments of the Present Disclosure> The following is a list and description of outlines of embodiments of the present disclosure: (1) A work vehicle of this embodiment is a work vehicle including a vehicle body, a fuel cell mounted on the vehicle body, and a tank unit having a tank capable of storing fuel, wherein the tank unit has a casing that houses the tank and an impact sensor that can detect an impact applied to the casing.

[0104] The work vehicle of this embodiment employs an impact sensor that can detect impacts applied to the casing that houses the tank, so the physical distance from the sensor to the tank can be shorter than when the impact sensor is mounted on the body of the work vehicle. This improves the accuracy of detecting impacts that occur in the tank, making it possible to provide a work vehicle that can accurately detect such impacts. Thus, the first object is achieved.

[0105] (2) In the work vehicle of (1) above, the tank unit may have a pipe connected to the tank and through which the fuel gas released from the tank flows, and an on-off valve capable of blocking the flow of the fuel gas in the pipe, and the on-off valve may close when the impact sensor detects the impact. In this way, the on-off valve automatically closes in response to the detection of the impact, thereby preventing gas leakage from the tank.

[0106] (3) In the work vehicle of (2) above, if a plurality of the tanks are housed in the casing and the piping includes a main pipe and branch pipes branching from the main pipe and leading to the tanks, the on-off valve may include at least one of a first valve disposed in the main pipe and a second valve disposed in each of the branch pipes. This is because gas leakage from the tank can be prevented by closing off gas flow in at least one of the main pipe and all of the branch pipes.

[0107] (4) In the work vehicle according to (1) to (3) above, the casing may have an outlet portion for discharging the fuel gas outside the casing, and the piping may include an outlet pipe connecting the tank and the outlet portion. In this way, the outlet pipe connects the tank and the outlet portion, and by connecting an external pipe leading to the fuel cell to the outlet portion, a supply path for the fuel gas from the tank to the fuel cell is formed.

[0108] (5) In the work vehicle according to any one of (1) to (4) above, the casing may have an inlet port for allowing the fuel gas to flow into the tank, and the piping may include an inlet pipe connecting the tank to the inlet port. In this way, the inlet pipe connects the tank to the inlet port, and by connecting a coupler of a hydrogen station to the inlet port, the tank can be filled with hydrogen from the hydrogen station.

[0109] (6) In the work vehicles described in (1) to (5) above, the tank unit may have a control device that closes the on-off valve in response to a detection signal from the impact sensor. In this case, since the tank unit has a control device that closes the impact sensor, the communication time lag is smaller than when another control device installed on the body of the work vehicle controls the impact sensor. Therefore, a work vehicle can be provided that can reduce the delay from impact detection to the valve closing operation. Thus, the second object is achieved.

[0110] (7) In the work vehicle of (6) above, the control device may be connected to a communication port for external communication provided on the casing. In this case, by connecting a communication cable connected to another control device on the vehicle side to the communication port, the control device of the tank unit can communicate with the other control device. Therefore, for example, information required for controlling the fuel cell can be exchanged with the other control device.

[0111] In addition, when another control device controls the opening and closing valve, the control device of the tank unit may transfer the detection signal of the impact sensor to the other control device, and the other control device that receives the detection signal may transfer a control command for the closing operation to the control device of the tank unit.

[0112] (8) The tank unit of this embodiment is a tank unit installed in a work vehicle whose power source is a fuel cell, and includes a tank that can be filled with fuel to be supplied to the fuel cell, a casing that houses the tank, and an impact sensor that can detect impacts applied to the casing.

[0113] The tank unit of this embodiment employs an impact sensor that can detect impacts applied to the casing that houses the tank, so the physical distance from the sensor to the tank can be shortened compared to when the impact sensor is mounted on the body of the work vehicle. This improves the accuracy of detecting impacts that occur in the tank, making it possible to provide a work vehicle that can accurately detect such impacts. Thus, the first objective is achieved.

[0114] (9) The tank unit of (8) above may further include a pipe connected to the tank and through which the fuel gas discharged from the tank flows, and an on-off valve capable of blocking the flow of the fuel gas in the pipe, wherein the on-off valve closes when the impact sensor detects the impact. In this way, the on-off valve automatically closes in response to the detection of the impact, thereby preventing gas leakage from the tank.

[0115] (10) In the tank unit of (9) above, a plurality of the tanks may be accommodated in the casing, the piping may include a main pipe and branch pipes branching from the main pipe and leading to the tanks, and the on-off valve may include at least one of a first valve disposed in the main pipe and a second valve disposed in the branch pipe. This is because gas leakage from the tank can be prevented by closing off the flow of fuel in at least one of the main pipe and all of the branch pipes.

[0116] <Details of Embodiments of the Present Disclosure> Hereinafter, details of embodiments of the present disclosure will be described with reference to the drawings. Note that at least some of the embodiments described below may be combined in any manner.

[0117] [Overall Structure of Work Vehicle] Figure 10 is a perspective view showing an example of the overall structure of the work vehicle 1. Figure 11 is a right side view of the work vehicle 1 with some exterior parts (such as the hood 34 and cover 111) removed. As shown in Figures 10 and 11 , the work vehicle 1 is a vehicle used for agricultural work, specifically a tractor. However, the work vehicle 1 is not limited to a tractor, and may be a mobile body such as agricultural machinery, construction machinery, or a utility vehicle.

[0118] The work vehicle 1 includes a vehicle body 11, a running device 12 that supports the vehicle body 11, a driver's seat 15, and a cabin 16. The vehicle body 11 includes a chassis 41, a hood 34, a cover 111, the cabin 16, and fenders for the rear wheels 12B. Specifically, the hood 34 and the cover 111 are mounted on the chassis 41 of the vehicle body 11 in this order from the front to the rear, and the cabin 16 is disposed behind the cover 111.

[0119] The work vehicle 1 further includes a tank unit 21 having multiple tanks 13 (see FIG. 11 ) therein for storing fuel, and a drive unit 14 that is driven by the stored fuel. The fuel is liquid or gas, and may be hydrogen, methane, carbon monoxide (CO), or the like. In this embodiment, the tank 13 stores hydrogen gas. The work vehicle 1 is a fuel cell vehicle (FCV). The work vehicle 1 includes a fuel cell power generation system (FC power generation system). The fuel cell 24 generates electricity using hydrogen. The fuel cell 24 may also generate electricity using methane or carbon monoxide (CO).

[0120] The drive device 14 includes a fuel cell 24, a battery unit 30, and an electric motor 31 (see FIG. 12 ; hereinafter also referred to as the "motor 31"). The battery unit 30 incorporates at least one battery pack 30A (see FIG. 13 ) that stores the output power of the fuel cell 24. The work vehicle 1 has an external pipe 22 for hydrogen gas. Hydrogen gas in the tanks 13 is supplied to the fuel cell 24 through the external pipe 22. The hydrogen gas is supplied from a gas filling connector 210 (see FIG. 14 ) of the tank unit 21 and filled into each tank 13.

[0121] The cabin 16 is a partitioned driver's compartment having front pillars, rear pillars, and a roof. The front pillars are located on the left and right sides in front of the driver's seat 15, and the rear pillars are located on the left and right sides behind the driver's seat 15. The work vehicle 1 may have a canopy or ropes instead of the cabin 16. When the work vehicle 1 is not equipped with the cabin 16, the tank unit 21 is disposed above the driver's seat 15 by a mounting frame 17, which will be described later.

[0122] The traveling device 12 is composed of front wheels 12A and rear wheels 12B, both of which are arranged symmetrically on the left and right sides of the vehicle body 11. One or both of the front wheels 12A and the rear wheels 12B rotate by the power of a motor 31. One or both of the wheels 12A, 12B (drive wheels) that rotate by the power of the motor 31 may be crawlers (crawlers).

[0123] 11 , a first radiator 48, a fuel cell 24, and a second radiator 49 are mounted in this order from front to rear on a portion of the chassis 41 corresponding to the front wheels 12A. The first radiator 48 and the fuel cell 24 are covered by the hood 34, and the second radiator 49 is covered by a cover 111.

[0124] 10, the top surface of the cover 111 is higher than the top edge of the hood 34 but lower than the top edge of the steering wheel of the driver's seat 15. The rear end of the hood 34 is located lower than the cover 111, and the top surface of the hood 34 is tapered from the rear end to the front end. This structure makes it difficult for the forward visibility of the operator sitting in the driver's seat 15 to be obstructed.

[0125] [Internal Structure of Work Vehicle] Figure 12 is a perspective view showing an example of the internal structure of the work vehicle 1. As shown in Figure 12, the chassis 41 that constitutes the vehicle body 11 is made of a steel frame that is long in the front-to-rear direction, and has a front frame 32 and a transmission case 33. The transmission case 33 is connected to the rear of the front frame 32, and the framework of the vehicle body 11 is formed by the transmission case 33 and the front frame 32.

[0126] A mounting frame 17 for disposing the tank unit 21 above the cabin 16 is connected to the chassis 41. The mounting frame 17 includes a substantially rectangular ceiling frame 17A that is longer in the front-to-rear direction than in the left-to-right direction, a plurality of pillars 17B that support the ceiling frame 17A from below, and a pair of left and right reinforcing frames 17C that are connected to the front end of the ceiling frame 17A.

[0127] The tank unit 21 is connected to the ceiling frame 17A in a horizontally placed state. As shown in Figure 11, the ceiling frame 17A is located higher than the roof of the cabin 16. Therefore, the tank unit 21 is disposed above the roof of the cabin 16. The reinforcing frame 17C is a reinforcing diagonal member that slopes downward from the front end of the ceiling frame 17A to the front frame 32. Therefore, the rigidity of the mounting frame 17 in the fore-and-aft direction is strengthened compared to when the ceiling frame 17A and the tank unit 21 are supported only by the pillars 17B.

[0128] A support frame 37 for supporting the battery unit 30 on the vehicle body 11 is connected to the chassis 41 of the work vehicle 1. Specifically, the motor 31 is mounted on the front frame 32 of the chassis 41, and the support frame 37 is attached to a portion of the front frame 32 corresponding to the motor 31. The support frame 37 is made of, for example, a metal frame member, and is attached in a cantilevered state so as to protrude to the right from the front frame 32.

[0129] The transmission case 33, located rearward of the motor 31, has a power transmission mechanism therein. The power transmission mechanism includes a transmission, a clutch, and a differential gear, and transmits the rotation of the output shaft of the motor 31 to the traveling device 12 while slowing or accelerating the rotation. The power transmission mechanism inside the transmission case 33 includes a branching mechanism that outputs a portion of the power of the motor 31 to a PTO shaft 334 (see FIG. 13 ). The PTO shaft 334 is an output shaft that protrudes rearward from the transmission case 33.

[0130] A coupling device 44 (see FIG. 11), which is configured, for example, by a three-point linkage mechanism, is attached to the transmission case 33 for coupling a work implement 335 (see FIG. 13; also referred to as an "implement") for performing a desired agricultural task to the rear of the vehicle body 11. The three-point linkage mechanism may be configured, for example, by an upper arm 44A that protrudes rearward from the transmission case 33 and a pair of lower arms 44B on the left and right. The work implement 335 is, for example, a cultivator or a baler.

[0131] For example, while the traveling device 12 is being driven, the rotational motion of the PTO shaft 334 is transmitted to the input shaft of the working device 335 connected to the coupling device 44. Therefore, the work vehicle 1 can drive the working device 335 with the power of the motor 31 while traveling in a field or the like.

[0132] [Functional Configuration of Work Vehicle] Fig. 13 is a block diagram showing an example of the functional configuration of the work vehicle 1. As shown in Fig. 13, the functional systems of the work vehicle 1 include a fuel system FS, a power system PS, and a temperature control system TS.

[0133] Components of the fuel system FS include an internal pipe 51, a gas coupler 52, an external pipe 22, and a tank unit 21. Components of the temperature control system TS include a plurality of radiators 48, 49 and an air conditioner 50. Components of the power system PS include a fuel cell 24, a boost circuit 61, an inverter 62, a motor 31, a transmission case 33, DC / DC converters 64, 65, and a battery unit 30.

[0134] The internal pipe 51 is a gas pipe arranged inside the vehicle body 11. The base end of the internal pipe 51 is connected to the fuel cell 24, and the tip end of the internal pipe 51 is connected to a gas coupler 52. The external pipe 22 is a gas pipe arranged outside the vehicle body 11. The base end of the external pipe 22 is connected to the gas coupler 52, and the tip end of the external pipe 22 is connected to a gas supply connector 215 (see FIG. 14 ) of the tank unit 21.

[0135] Therefore, hydrogen gas ejected from the tank unit 21 is supplied to the fuel cell 24 via the external piping 22 and the internal piping 51. The motor 31 has a rotor and a stator having a plurality of coils, and drives an output shaft at a predetermined torque and rotational speed. For example, only one motor 31 is mounted on the work vehicle 1, and the output shaft of the motor 31 is coupled to a transmission case 33.

[0136] A plurality of motors 31 may be mounted. For example, if two types of motors 31 are provided, one for the front wheels 12A and one for the rear wheels 12B, the power of each motor 31 may be output to the front wheels 12A and the other to the rear wheels 12B. The power transmission mechanism of the transmission case 33 outputs all or part of the power of the motor 31 to the traveling device 12. Furthermore, when operating the working device 335, the power transmission mechanism also outputs the power of the motor 31 to the PTO shaft 334.

[0137] The fuel cell 24 is, for example, a battery module configured by stacking a plurality of unit cells, each having a positive electrode and a negative electrode, side by side. The fuel cell 24 aggregates the electric power generated by each unit cell to generate the electric power required to drive the electric motor 31. The fuel cell 24 is connected to the second radiator 49 through a coolant flow path H2. That is, the electrodes are adjusted to a predetermined temperature by the coolant circulated from the second radiator 49. This allows the fuel cell 24 to maintain high power generation efficiency.

[0138] The fuel cell 24 is electrically connected to the input side of a boost circuit 61, and the output side of the boost circuit 61 is electrically connected to the DC side of an inverter 62. The boost circuit 61 boosts the voltage input from the fuel cell 24 and outputs it to the inverter 62 and the battery unit 30. The inverter 62 is electrically connected to the motor 31. The inverter 62 converts the DC input from the boost circuit 61 into three-phase AC and outputs it to the motor 31. Therefore, the power generated by the fuel cell 24 is boosted and converted into AC and transmitted to the motor 31.

[0139] The battery unit 30 is a power storage device that absorbs load fluctuations of the fuel cell 24. Specifically, the battery unit 30 temporarily charges with power supplied from the boost circuit 61, and discharges it under high load to supply drive power for the motor 31 to the inverter 62. The battery unit 30 includes a battery pack 30A and a monitoring unit 30B. The battery pack 30A includes at least one cell. The cell is, for example, a charge-discharge type cell such as a lithium-ion battery cell. The output voltage of the battery unit 30 is, for example, 24 V.

[0140] The monitoring unit 30B includes a processor that controls switching of the operation (charging or discharging) of the battery pack 30A and measures the state of charge (e.g., SOC). The monitoring unit 30B stores, for example, an SOC-OCV curve that defines the correspondence relationship between the open circuit voltage and SOC of the battery pack 30A. The processor of the monitoring unit 30B can measure the SOC of the battery pack 30A based on the OCV value detected by a voltage sensor (not shown) and the curve.

[0141] The work vehicle 1 has a plurality of electrical components that operate at a lower voltage than the motor 31. These electrical components are supplied with DC power that has been stepped down by a step-down circuit. The plurality of electrical components includes, for example, an auxiliary battery 63, radiators 48, 49, and an air conditioning unit 50. The step-down circuit is, for example, a plurality of DC / DC converters 64, 65 (hereinafter also referred to as the "first converter 64" and the "second converter 65") that have different output voltages.

[0142] The first converter 64 steps down the DC voltage input from the boost circuit 61 to a first voltage (e.g., 12 volts) and supplies it to the auxiliary battery 63, the air conditioning device 50, etc. The second converter 65 steps down the DC voltage input from the boost circuit 61 to a second voltage (e.g., 24 volts) and supplies it to the radiators 48, 49. The inverter 62 and both converters 64, 65 are disposed in a portion of the chassis 41 corresponding to the driver's seat 15. The second voltage of the second converter 65 may be supplied to the battery unit 30.

[0143] As described above, the first radiator 48 is disposed in front of the fuel cell 24, and the second radiator 49 is disposed behind the fuel cell 24 (see FIG. 11). These radiators 48, 49 constitute a cooling system that uses a coolant (refrigerant) to cool electrical components such as the fuel cell 24, boost circuit 61, inverter 62, motor 31, and first and second converters 64, 65.

[0144] A cooling flow path H1, through which coolant is circulated by a pump 66, is connected to the first radiator 48, and the coolant is cooled by heat exchange with the external air. The first radiator 48 has a first fan 35 for promoting heat exchange with the external air. The cooling flow path H1 of the first radiator 48 cools electrical components (heat-generating components), such as the boost circuit 61, the inverter 62, the motor 31, and the first and second converters 64, 65.

[0145] A cooling flow path H2, through which coolant is circulated by a pump 67, is connected to the second radiator 49, and the coolant is cooled by heat exchange with the outside air. The second radiator 49 has a second fan 36 for promoting heat exchange with the outside air. The object to be cooled by the cooling flow path H2 of the second radiator 49 is, for example, an electrical component such as the fuel cell 24.

[0146] The auxiliary battery 63 is an electricity storage device that supplies power to the display, communication devices, and the like mounted in the driver's seat 15. The auxiliary battery 63 is, for example, a charge-discharge type lead-acid battery. The output voltage of the auxiliary battery 63 is, for example, 12 V, which is lower than the output voltage (for example, 24 V) of the battery unit 30. The auxiliary battery 63 can also be used as an auxiliary power source that supplies power to the control device 70 (described later) when the fuel cell 24 is stopped.

[0147] 13, an in-vehicle communication network 71 including, for example, at least one control device 70 is established in the work vehicle 1. The control device 70 is configured by, for example, an ECU (Electronic Control Unit) that communicates with various electrical components using a communication protocol such as CAN (Controller Area Network).

[0148] A communication port 72 is connected to the in-vehicle communication network 71 for wired communication with an external device, such as a control device 206 (see FIG. 14 ) of the tank unit 21, which will be described later. A communication cable 73 conforming to a predetermined communication protocol for external communication is connected to the communication port 72. The communication cable 73 is connected to, for example, a communication port 223 (see FIG. 14 ) of the tank unit 21, which will be described later.

[0149] [Internal Configuration of Tank Unit] Fig. 14 is a block diagram showing an example of the internal configuration of the tank unit 21. As shown in Fig. 14, the tank unit 21 includes a casing 200, and a fuel equipment FE and an electrical equipment EP each housed in the casing 200.

[0150] The fuel equipment FE includes a plurality of hydrogen tanks 13 and pipes 201, 202 connected to each hydrogen tank 13. The pipes 201, 202 inside the casing 200 include an inlet pipe 201 and an outlet pipe 202. The electrical equipment EP includes an impact sensor 203, electromagnetic valves 204, 205, a control device 206, and a line concentrator 207. The electromagnetic valves 204, 205 function as "open / close valves" that close or open the gas flow in the pipes.

[0151] The casing 200 may be a substantially rectangular parallelepiped housing made of metal or synthetic resin. The casing 200 is not limited to a housing with all walls sealed, but may be, for example, a housing or frame with a hole in at least one wall. The multiple tanks 13 may be, for example, three hydrogen tanks 13. Each tank 13 is equipped with a temperature sensor 222. The number of hydrogen tanks 13 may be four or more, or two or less.

[0152] The inlet pipe 201 is a pipe for allowing hydrogen to flow into the multiple tanks 13. The inlet pipe 201 includes branch pipes 208 connected to each of the tanks 13, and one main pipe 209 to which all of the branch pipes 208 are connected. The main pipe 209 is connected to a gas filling connector 210 provided on the wall of the casing 200. The gas filling connector 210 functions as an "inlet section" that allows hydrogen to flow into the hydrogen tank 13. The branch pipes 208 and the main pipe 209 are each provided with a check valve 211. One of the multiple branch pipes 208 is provided with a pressure sensor 212 that detects the gas inlet pressure.

[0153] The outflow pipe 202 is a pipe for causing hydrogen to flow out from the multiple tanks 13. The outflow pipe 202 includes branch pipes 213 connected to each of the tanks 13, and one main pipe 214 to which all of the branch pipes 213 are connected. The main pipe 214 is connected to a gas supply connector 215 fixed to the wall of the casing 200. The gas supply connector 215 functions as an "outflow section" that causes hydrogen to flow out of the casing 200. The branch pipe 213 and the main pipe 214 are provided with electromagnetic valves 204, 205, respectively. The main pipe 214 is provided with a pressure sensor 217 that detects the gas outflow pressure.

[0154] A vent pipe 218 that can be opened by an on-off valve 219 is connected to the main pipe 214 of the outflow pipe 202. The outlet end of the vent pipe 218 is connected to a gas outlet 220 provided in the wall of the casing 200. The gas outlet 220 may also be connected to a piping device that can release hydrogen more safely, for example, at high altitudes. A pressure adjustment valve 221 is provided in the main pipe 214 of the outflow pipe 202 to adjust the supply pressure of hydrogen from the tank 13.

[0155] The concentrator 207 is, for example, a multi-port concentrator for sensors and actuators. The concentrator 207 aggregates the wiring of multiple sensors and actuators into one and routes the aggregated wiring to the control device 206 via a master cable. Therefore, the following multiple cables are connected to each port of the concentrator 207.

[0156] 1) A sensor cable connected to the impact sensor 203; 2) A sensor cable connected to the pressure sensor 212; 3) A sensor cable connected to the pressure sensor 217; 4) A sensor cable connected to the temperature sensor 222; 5) An actuator cable connected to the electromagnetic valve 204; and 6) An actuator cable connected to the electromagnetic valve 205.

[0157] The control device 206 is configured with an ECU that communicates with various electrical components using a communication protocol such as CAN. The control device 206 may also communicate with sensors using serial communication such as SENT (Single Edge Nibble Transmission). The control device 206 is connected to the concentrator 207 via a master cable and to a communication port 223 via a communication cable for external communication. The communication port 223 is connected to a communication cable 73 that leads to a communication port 72 (see FIG. 13 ) on the vehicle side.

[0158] In this way, by connecting the communication cable 73 to the communication port 223, the control device 206 of the tank unit 21 becomes a communication node belonging to the in-vehicle communication network 71. Therefore, the control device 206 can exchange information necessary for controlling the fuel cell 24, etc. with other control devices 70. For example, in response to an information request from the control device 70, the control device 206 calculates the amount of hydrogen gas filled from the measured values ​​of the pressure sensors 212, 217, and transmits an information response including the calculated amount of filled to the control device 70.

[0159] The impact sensor 203 is a sensor capable of detecting an impact occurring in the casing 200. For example, at least one of an acceleration satellite sensor and a satellite pressure sensor may be used as the impact sensor 203. The impact sensor 203 is installed, for example, on the inner surface of the wall of the casing 200. In the example of FIG. 14 , one impact sensor 203 is installed, but multiple impact sensors 203 may be installed. In this case, an impact sensor 203 may be installed for each direction in which impact detection is desired.

[0160] 14, the control device 206 of the tank unit 21 can execute "emergency closing control." The emergency closing control is a control for closing the electromagnetic valves 204 and 205 in response to the detection of an impact by the impact sensor 203.

[0161] Specifically, the control device 206 constantly monitors whether the detection signal input from the impact sensor 203 is equal to or greater than a predetermined threshold, and if the detection signal is equal to or greater than the threshold, outputs a control signal for closing the electromagnetic valves 204, 205. This makes it possible to prevent hydrogen from leaking from the outflow pipe 202 even if an impact occurs to the casing 200.

[0162] The tank unit 21 of this embodiment employs an impact sensor 203 that can detect an impact applied to the casing 200 that houses the hydrogen tank 13, and so the physical distance from the sensor to the hydrogen tank 13 can be shortened compared to when the impact sensor 203 is provided on the body 11 of the work vehicle 1. This improves the accuracy with which an impact occurring in the hydrogen tank 13 can be detected, making it possible to provide a work vehicle 1 that can accurately detect such an impact.

[0163] Furthermore, according to the tank unit 21 of this embodiment, the control device 206 that closes the impact sensor 203 is mounted on the tank unit 21, so the communication time lag is smaller than when the impact sensor 203 is controlled by another control device 70 provided on the body 11 of the work vehicle 1. Therefore, it is possible to provide a work vehicle 1 that can reduce the delay from impact detection to the valve closing operation.

[0164] It is also possible to employ a system in which the vehicle-side control device 70 controls the electromagnetic valves 204, 205. In this case, the control device 206 of the tank unit 21 transfers a detection signal from the impact sensor 203 to the vehicle-side control device 70, and the control device 70, having received the detection signal, transfers a control command for the closing operation to the control device 206 of the tank unit 21.

[0165] However, the tank unit 21 used in fuel cell-powered agricultural or construction machinery can be mounted in a variety of positions. As will be described later, the tank unit 21 may also be towed. Considering this variety of mounting configurations, it is preferable to mount the control device 206 and the impact sensor 203 on the casing 200 of the tank unit 21.

[0166] Furthermore, for off-road mobility, access to hydrogen stations is difficult. For this reason, tank units 21 that can be replaced individually may be adopted, and their shapes may vary widely. In this case, if the impact sensor 203 and control device 206 are housed in the casing 200, the impact sensor 203 can be positioned in a position that is suitable for the internal structure of the unit 21.

[0167] [Modification of Work Vehicle] Figure 15 is an explanatory diagram showing an example of a towing-type work vehicle 1. In the work vehicle 1 shown in Figure 15, a connecting member 401 of a trailer 400 that carries the tank unit 21 is detachably connected to the rear of the vehicle. In this way, the work vehicle 1 is not limited to the mounted type (Figure 10) in which the tank unit 21 is mounted on the vehicle body 11, and a configuration in which the work vehicle 1 tows the tank unit 21 with a trailer 400 or the like may be adopted.

[0168] Even in a towing-type work vehicle 1, hydrogen gas can be supplied to the fuel cell 24 by connecting the tank unit 21 and the work vehicle 1 with external piping 22. Furthermore, by connecting the tank unit 21 and the in-vehicle communication network 71 with a communication cable 73, the control device 206 of the tank unit 21 can be included as a communication node of the network.

[0169] [Other Modifications] The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is not limited to the above-described embodiments, and includes all modifications within the scope equivalent to the configurations described in the claims. For example, in the above-described embodiments, the mounting position of the tank unit 21 is not limited to above the cabin 16, but may be to the side or rear of the cabin 16, etc.

[0170] The symbols used in Chapter 2 are used only in this Chapter 2 and are unrelated to the symbols in other chapters. The configurations disclosed in Chapter 1 are applicable to the inventions disclosed in Chapter 2, and vice versa.

[0171] [Explanation of symbols] 1 Work vehicle 11 Body 12 Traveling device 12A Front wheels 12B Rear wheels 12A, 12B Wheels 13 Hydrogen tank (tank) 14 Drive device 15 Driver's seat 16 Cabin 17 Mounting frame 17A Ceiling frame 17B Pillar 17C Reinforcement frame 21 Tank unit 22 External piping 24 Fuel cell 30 Battery unit 30A Battery pack 30B Monitoring unit 31 Electric motor 31 Motor 32 Front frame 33 Transmission case 34 Bonnet 35 First fan 36 Second fan 37 Support frame 41 Chassis 44 Coupling device 44A Upper arm 44B Lower arm 48 First radiator 49 Second radiator 50 Air conditioning device 51 Internal piping 52 Gas coupler 61 Boost circuit 62 Inverter 63 Auxiliary battery 64 First converter 65 Second converter 66 Pump 67 Pump 70 Control device 71 In-vehicle communication network 72 Communication port 73 Communication cable 111 Cover 200 Casing 201 Inlet pipe (piping) 202 Outlet pipe (piping) 203 Impact sensor 204 Solenoid valve (opening / closing valve) 205 Solenoid valve (opening / closing valve) 206 Control device 207 Concentrator 208 Branch pipe 209 Main pipe 210 Connector for gas filling (inlet portion) 211 Check valve 212 Pressure sensor 213 Branch pipe 214 Main pipe 215 Connector for gas supply (outlet portion) 217 ​​Pressure sensor 218 Vent pipe 219 Opening / closing valve 220 Gas exhaust port 221 Pressure regulating valve 222 Temperature sensor 223 Communication port 334 PTO shaft 335 Work device 400 Trailer 401 Connecting member

Claims

1. A work machine having a vehicle body capable of traveling, a tank mounted on the vehicle body, a fuel cell, a valve capable of shutting off a supply path from the tank to the fuel cell, and a detection device provided on the vehicle body, wherein the vehicle body travels based on detection information of the detection device, and the valve is closed when it is determined that the traveling situation of the vehicle body obtained from the detection information is dangerous.

2. The detection device is capable of detecting obstacles around the vehicle body, and the vehicle body performs an operation of avoiding the obstacle or an operation of stopping the traveling when the position between the obstacle detected by the detection device and the vehicle body is equal to or less than a predetermined distance. The valve is closed assuming that the traveling situation is dangerous when the position between the obstacle and the vehicle body is equal to or less than a predetermined distance. The work machine according to claim 1.

3. The detection device includes at least one of a LiDAR sensor, a millimeter-wave radar, and an ultrasonic sensor, and the valve is closed based on the detection information detected by at least one of the LiDAR sensor, the millimeter-wave radar, and the ultrasonic sensor. The work machine according to claim 1 or 2.

4. When a signal from an operating device operated by a user is acquired, the valve switches from a closed state to an open state. The work machine according to any one of claims 1 to 3.

5. When the valve switches from a closed state to an open state, the vehicle body stops an operation of avoiding the obstacle or an operation of stopping the traveling. The work machine according to claim 4.

6. Having a tank unit having the tank and a support member for supporting the tank, and the valve is provided in the tank unit. The work machine according to any one of claims 1 to 5.

7. A work vehicle comprising a vehicle body, a fuel cell mounted on the vehicle body, and a tank unit having a tank capable of storing fuel, wherein the tank unit has a casing for housing the tank and a shock sensor capable of detecting a shock applied to the casing.

8. The tank unit has a pipe connected to the tank and through which the gas of the fuel discharged from the tank flows, and an on-off valve capable of shutting off the flow of the gas of the fuel in the pipe. The on-off valve closes when the impact sensor detects the impact. The work vehicle according to claim 7.

9. A plurality of the tanks are accommodated in the casing. The pipe includes a main pipe and branch pipes branched from the main pipe and each communicating with the tank. The on-off valve includes at least one of a first valve disposed in the main pipe and second valves respectively disposed in the branch pipes. The work vehicle according to claim 8.

10. The casing has an outflow portion for allowing the gas of the fuel to flow out of the casing. The pipe includes an outflow pipe connecting the tank and the outflow portion. The work vehicle according to any one of claims 7 to 9.

11. The casing has an inflow portion for allowing the gas of the fuel to flow into the tank. The pipe includes an inflow pipe connecting the tank and the inflow portion. The work vehicle according to any one of claims 7 to 10.

12. The tank unit has a control device for closing the on-off valve according to a detection signal of the impact sensor. The work vehicle according to any one of claims 7 to 11.

13. The control device is connected to a communication port for external communication provided in the casing. The work vehicle according to claim 12.

14. A tank unit provided in a work vehicle whose drive source is a fuel cell, the tank unit including a tank capable of filling fuel to be supplied to the fuel cell, a casing for accommodating the tank, and an impact sensor capable of detecting an impact applied to the casing.

15. The tank unit has a pipe connected to the tank and through which the gas of the fuel discharged from the tank flows, and an on-off valve capable of shutting off the flow of the gas of the fuel in the pipe. The on-off valve closes when the impact sensor detects the impact. The tank unit according to claim 14.

16. The tank is accommodated in the casing in plurality, the pipe includes a main pipe and branch pipes branched from the main pipe and each communicating with the tank, and the on-off valve includes at least one of a first valve disposed in the main pipe and a second valve disposed in the branch pipe, the tank unit according to claim 15.

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