Work machine

Abstract

This work machine comprises: a fuel cell; an electric motor driven by electric power generated by the fuel cell; and a drain pipe line that is connected to the fuel cell and drains generated water generated by the fuel cell. The drain pipe line has a first drain pipe line and a second drain pipe line that guide the generated water to the outside. The first drain pipe line and the second drain pipe line are disposed so as to extend from the fuel cell to mutually opposite sides.

Description

Work machine

[0001] The present invention relates to a work machine such as a hydraulic excavator equipped with a fuel cell system.

[0002] In recent years, work machines such as construction machines have been proposed that are equipped with a fuel cell system that does not emit greenhouse gases (see, for example, Patent Document 1). The fuel cell system includes a fuel cell that supplies power to an electric motor serving as a power source, and a hydrogen storage container that stores hydrogen supplied to the fuel cell.

[0003] The fuel cell generates electricity using hydrogen and oxygen (air), and water is generated as a byproduct at that time. In the case of construction machines, since the required power is greater compared to passenger vehicles, the generated water (product water) also becomes a large amount. Also, in cold regions, etc., there is a risk that the product water will freeze, so it is desirable to drain the product water out of the vehicle body sequentially without accumulating it inside the vehicle body.

[0004] Japanese Patent Application Laid-Open No. 2022-180565

[0005] By the way, in work machines, situations such as long-term work on sloping ground and parking may occur. In such situations, there are problems that the drainage of the product water is hindered by the inclination of the vehicle body, or water remains in the drainage pipe.

[0006] The work machine according to an aspect of the present invention is a work machine including a fuel cell, an electric motor driven by the generated power of the fuel cell, and a drainage pipe connected to the fuel cell for draining the product water generated in the fuel cell, wherein the drainage pipe has a first drainage pipe and a second drainage pipe that lead the product water to the outside of the vehicle, and the first drainage pipe and the second drainage pipe are arranged to extend from the fuel cell to opposite sides of each other.

[0007] According to the present invention, the product water generated by the fuel cell can be drained to the outside of the vehicle body even when the vehicle body is inclined.

[0008] Figure 1 is a diagram showing the schematic configuration of a hydraulic excavator. Figure 2 is a block diagram showing the system configuration of a hydraulic excavator. Figure 3 is a block diagram illustrating drainage control. Figure 4 is a diagram illustrating the angle of the drainage pipeline. Figure 5 is a flowchart showing an example of drainage pipeline selection operation. Figure 6 is a diagram showing an example of drainage environment information displayed on a display device. Figure 7 is a diagram showing a modified example of the drainage pipeline system.

[0009] Embodiments of the work machine according to the present invention will be described below with reference to the drawings. The following description and drawings are illustrative examples for explaining the present invention, and have been omitted and simplified as appropriate for clarity of explanation. In addition, in the following description, the same or similar elements and processes are denoted by the same reference numerals, and redundant explanations may be omitted. It should be noted that the contents described below are merely examples of embodiments of the present invention, and the present invention is not limited to the embodiments described below, and can be implemented in various other forms.

[0010] Hereinafter, a hydraulic excavator will be used as an example of a working machine according to the embodiment of the present invention, but the present invention can be applied to various working machines, not limited to hydraulic excavators. Figure 1 is a diagram showing the schematic configuration of a hydraulic excavator 100. The hydraulic excavator 100 comprises a lower traveling body 3 equipped with a pair of left and right tracks 1a and 1b, an upper rotating body 4 attached to the upper part of the lower traveling body 3, and a front device 2 provided on the front side of the upper rotating body 4.

[0011] The front device 2 comprises a boom 5 rotatably pin-connected to one end of the upper slewing body 4, an arm 6 rotatably pin-connected to one end of the boom 5, and a bucket 7 rotatably pin-connected to one end of the arm 6. The boom 5 is driven by the extension and retraction of a pair of left and right boom cylinders 14a and 14b. The arm 6 is driven by the extension and retraction of the arm cylinder 16. The bucket 7 is driven by the extension and retraction of the bucket cylinder 17. The posture of the front device 2 is determined by the extension and retraction of the boom cylinders 14a and 14b, the arm cylinder 16, and the bucket cylinder 17, respectively.

[0012] The lower traveling body 3 is equipped with travel motors 11a and 11b that drive the tracks 1a and 1b. The upper slewing body 4 is equipped with a driver's cab 8, a machine room 9, and a counterweight 10. The machine room 9 houses the slewing motor 13, electric motor 23, fuel cell 21, hydrogen tank 50, and main pump 31, which will be described later. Below the machine room 9, a switching valve 75 and drainage pipes 70b and 70c are provided for draining the water generated by the fuel cell 21 from the upper slewing body 4.

[0013] Figure 2 is a block diagram showing the system configuration of the hydraulic excavator 100. Note that the travel motors 11a, 11b and the slewing motor 13 all have the same configuration as hydraulic motors. Therefore, in the following explanation, the slewing motor 13 will be used as an example to represent the hydraulic motors, and the illustration and explanation of the travel motors 11a and 11b in Figure 2 will be omitted. Similarly, the boom cylinders 14a, 14b, the arm cylinder 16, and the bucket cylinder 17 all have the same configuration as hydraulic cylinders. Therefore, in the following explanation, the arm cylinder 16 will be used as an example to represent the hydraulic cylinders, and the illustration and explanation of the boom cylinders 14a, 14b, and the bucket cylinder 17 will be omitted.

[0014] The hydraulic circuit 30 includes a main pump 31 and a pilot pump 32, a hydraulic fluid tank 33 for storing hydraulic fluid, a swing motor 13 representing a hydraulic motor, a first directional control valve 34 for controlling the flow of hydraulic fluid related to the swing motor 13, an arm cylinder 16 representing a hydraulic cylinder, and a second directional control valve 35 for controlling the flow of hydraulic fluid related to the arm cylinder 16, etc.

[0015] The main pump 31 is a variable displacement hydraulic pump driven by an electric motor 23. This main pump 31 draws hydraulic fluid from the hydraulic fluid tank 33 and supplies it to the swing motor 13 and the arm cylinder 16, respectively, via the first directional control valve 34 and the second directional control valve 35. In this embodiment, a variable displacement hydraulic pump is used for the main pump 31, but it is not limited to this, and a fixed displacement hydraulic pump may also be used.

[0016] The pilot pump 32 is a fixed-displacement hydraulic pump driven by an electric motor 23. This pilot pump 32 draws hydraulic fluid from the hydraulic fluid tank 33 and supplies it to the pair of pressure-receiving chambers 34A and 34B of the first directional control valve 34 and the pair of pressure-receiving chambers 35A and 35B of the second directional control valve 35.

[0017] Furthermore, the hydraulic circuit 30 is provided with a main relief valve 36 that defines the upper limit of the discharge pressure of the main pump 31, a pilot relief valve 37 that defines the upper limit of the discharge pressure of the pilot pump 32, and an on-off valve 38 that opens and closes the pipeline between the second directional control valve 35 and the hydraulic oil tank 33. A heat exchanger 81 is provided in the pipeline through which the hydraulic oil returns to the hydraulic oil tank 33.

[0018] The driver's cab 8 shown in Figure 1 is equipped with a work mode selection switch 41, a motor control dial 42 for setting the rotation speed of the electric motor 23 (described later), operating levers 43A and 43B, a display device 77, and a vehicle controller 45. Operating lever 43A is an operating lever for controlling the swing motor 13. Operating lever 43B is an operating lever for controlling the arm cylinder 16. For example, electric levers that output an electrical operating signal (lever signal Lv) according to the amount of operation are used for operating levers 43A and 43B. The lever signals Lv of operating levers 43A and 43B are input to the vehicle controller 45. The vehicle controller 45 outputs command signals according to the lever signals Lv to the electromagnetic proportional valves 34a and 34b of the first directional control valve 34 and the electromagnetic proportional valves 35a and 35b of the second directional control valve 35, controlling the switching direction and stroke amount of each directional control valve 34 and 35.

[0019] At the same time, the vehicle controller 45 controls the pump capacity (discharge flow rate) of the hydraulic pump 31 by outputting command signals to the regulator 61 of the hydraulic pump 31 according to the lever signal Lv, the pump discharge pressure sensor 62, and the electric motor rotation speed sensor (not shown). With this configuration, the desired operation can be made to each hydraulic actuator by operating levers 43A and 43B.

[0020] The first directional control valve 34, which is a center bypass type directional control valve, has a first switching position 34L that rotates the swing motor 13 in the forward direction, a neutral position 34N that connects the main pump 31 and the hydraulic oil tank 33 and returns the hydraulic oil directly to the hydraulic oil tank 33, and a second switching position 34R that rotates the swing motor 13 in the reverse direction. The first directional control valve 34 is configured to switch to one of the first switching position 34L, the neutral position 34N, or the second switching position 34R by the stroke of an internal spool in response to the pilot pressure acting on a pair of pressure-receiving chambers 34A and 34B, respectively. This controls the flow rate and direction (flow) of the hydraulic oil supplied from the main pump 31 to the swing motor 13.

[0021] The second directional control valve 35 is a center bypass type directional control valve, similar to the first directional control valve 34. The second directional control valve 35 has a first switching position 35L that retracts the rod 16C of the arm cylinder 16, a neutral position 35N that connects the main pump 31 and the hydraulic oil tank 33 and returns the hydraulic oil directly to the hydraulic oil tank 33, and a second switching position 35R that extends the rod 16C of the arm cylinder 16. Similar to the first directional control valve 34, the second directional control valve 35 is configured to switch to one of the first switching position 35L, the neutral position 35N, or the second switching position 35R by the stroke of an internal spool in response to the pilot pressure acting on a pair of pressure-receiving chambers 35A and 35B, respectively. This controls the flow rate and direction (flow) of the hydraulic oil supplied from the main pump 31 to the arm cylinder 16.

[0022] The on / off valve 38 is an electromagnetic proportional valve whose opening degree is adjusted in proportion to the magnitude of the command current, and whose opening area is adjusted in proportion to the magnitude of the command current from the vehicle body controller 45. Therefore, the pressure of the main pump 31 can be freely set even when the system is not in operation or when the hydraulic actuator load is small.

[0023] The hydraulic excavator 100 operates by driving the main pump 31 with an electric motor 23. The electric motor 23 is driven by the power generated by a fuel cell 21, which generates electricity using air and hydrogen supplied from a hydrogen tank 50. The high-voltage system 20 consists of an inverter 22, an electric motor 23, a secondary battery 25, a high-voltage DC-DC converter 29, a fuel cell 21, a boost converter 28, and a low-voltage DC-DC converter 63, which are electrically connected by high-voltage cables.

[0024] Since the output of the fuel cell 21 is controlled by voltage, voltage conversion is required between the fuel cell voltage and the system voltage (e.g., 650V). Therefore, the fuel cell 21 is equipped with a boost converter 28 to boost the voltage, which corresponds to the rated voltage of the inverter 22. The inverter 22 converts the DC voltage (system voltage) boosted by the boost converter 28 into AC voltage to control the rotational speed of the electric motor 23. The high-voltage DC-DC converter 29 is a bidirectional voltage converter that either steps down the system voltage to charge the secondary battery 25, or steps up the voltage of the secondary battery 25 to the system voltage and supplies it to the inverter 22.

[0025] The secondary battery 25 can store energy using surplus power generated by the fuel cell 21 and also functions as a power source to supply power to a load including the electric motor 23. Here, the secondary battery 25 can be any rechargeable energy storage device, and can be made up of, for example, a lithium-ion capacitor, lithium-ion battery, nickel-metal hydride battery, etc. The secondary battery 25 is equipped with a sensor (not shown) for detecting the operating status of the secondary battery 25, such as voltage, current, and remaining capacity (SOC).

[0026] The vehicle controller 45 is a higher-level controller that oversees the entire system of the hydraulic excavator 100, and outputs appropriate command values ​​to the electromagnetic proportional valves (34a, 34b, 35a, 35b) of the hydraulic circuit 30, lower-level controllers (fuel cell controller 47, battery controller 46), low-voltage DC-DC converter 63, inverter 22, switching valve 75 (described later), etc. These controllers are connected to a low-voltage circuit 60 (for example, voltage 24V) which includes a lead-acid battery 61.

[0027] The low-voltage circuit 60 is connected to the low-voltage DC-DC converter 63 described above, which generates a stable low voltage using power from the high-voltage system 20. The lead-acid battery 66 is connected to the low-voltage circuit 60 via a disconnect switch 65. This configuration makes it possible to shut off the system power supply, which helps prevent battery depletion, theft, and improves the safety of vehicle maintenance. A key switch 64 is connected to the vehicle controller 45, and the vehicle operation is started and stopped by operating the key switch 64.

[0028] Figure 3 is a block diagram illustrating the drainage control in the hydraulic excavator 100. The fuel cell 21 is supplied with hydrogen from the hydrogen tank 50 and air taken in from the atmosphere and compressed by the compressor 58. In the fuel cell 21, water is produced as a by-product during power generation. Generally, it is necessary to keep the inside of the fuel cell 21 humidified to promote hydrogen ionization, and a certain amount of moisture is required, but excess moisture is discharged outside the vehicle body through the drainage pipeline system 70.

[0029] The drainage pipeline system 70 consists of a drainage pipeline 70a connected to the fuel cell 21, a switching valve 75 for controlling drainage, and drainage pipelines 70b and 70c extending in the approximate front-rear direction of the upper swivel body 4. As shown in Figure 1, drainage pipeline 70b extends to the front side of the upper swivel body 4 in the front-rear direction, while drainage pipeline 70c extends to the rear side. It is preferable that the drainage pipelines 70b and 70c be set so that there are no upward slopes in the direction of extension, taking drainage into consideration. Preferably, they should have a downward slope in the direction of extension, as shown in Figure 1. In this embodiment, the two drainage pipelines 70b and 70c are configured to extend along the approximate front-rear direction of the upper swivel body 4 as shown in Figure 1, but the direction of extension of the drainage pipelines 70b and 70c is not limited to the front-rear direction. For example, they may be in a direction tilted to the left or right with respect to the front and rear, or they may be in the left-right direction. In either case, the drainage directions of the drainage pipes 70b and 70c should be in opposite directions.

[0030] The vehicle body controller 45 is connected to a tilt sensor 72, an imaging device 73, a display device 77, and a drainage operation device 78. The tilt sensor 72 and the imaging device 73 input drainage environment information related to drainage, such as vehicle body tilt information and surrounding images. Note that the tilt sensor 72, imaging device 73, and drainage operation device 78 are not shown in Figure 2. The tilt sensor 72 and the imaging device 73 are installed, for example, on the upper rotating body 4. The tilt sensor 72 uses an IMU (Inertial Measurement Unit) or the like, and can acquire the tilt angles of the upper rotating body 4 in the front-rear and left-right directions. The drainage operation device 78 is installed in the driver's cab 8 (see Figure 1).

[0031] The vehicle controller 45 controls the direction of water drainage by controlling the switching valve 75 based on this drainage environment information. As will be described later, the display device 77 displays vehicle tilt information and the drainage status by the switching valve 75 as drainage environment information. The operator of the hydraulic excavator 100 can manually control the switching valve 75 using the drainage operation device 78 based on the drainage environment information displayed on the display device 77. The switching valve 75 has a first switching position 75L for draining water from the drainage pipe 70b, a neutral position 75N for draining water from both drainage pipes 70b and 70c, and a second switching position 75R for draining water from the drainage pipe 70c.

[0032] Returning to Figure 2, the system operation in this embodiment will be described. When the driver turns on the key switch 64 in the driver's cab 8, the vehicle controller 45 is activated. The vehicle controller 45 activates the inverter 22, the low-voltage DC-DC converter 63, the battery controller 46, and the fuel cell controller 47. As a result, the battery controller 46 activates the secondary battery 25 and the high-voltage DC-DC converter 29, and the fuel cell controller 47 activates the fuel cell 21, the boost converter 28, and the hydrogen valve (not shown) connected to the hydrogen tank 50. The vehicle controller 45 controls the power generation of the fuel cell 21, the driving of the electric motor 23, the hydraulic circuit 30, etc., according to the settings of the work mode selection switch 41 and the motor control dial 42, and the lever signals Lv of the operation levers 43A and 43B.

[0033] On the other hand, when the driver turns OFF the key switch 64 in the driver's cab 8, the vehicle controller 45 stops the electric motor 23 by stopping the inverter 22. At the same time, the fuel cell controller 47 stops the fuel cell 21, the boost converter 28, and the hydrogen valve (not shown) connected to the hydrogen tank 50, thereby stopping power generation. After the fuel cell controller 47 has finished its shutdown process (after power generation has stopped), the vehicle controller 45 stops the low-voltage DC-DC converter 63 and the battery controller 46. Through this operation, surplus power in the high-voltage system 20 during the shutdown process is used to charge the lead-acid battery 61 and the secondary battery 25, ensuring safety.

[0034] As mentioned above, while the vehicle is in operation, generated water is produced by the power generation of the fuel cell 21. The generated water is drained outside the vehicle through the drainage pipeline system 70. As shown in Figure 3, the drainage pipeline system 70 includes a drainage pipeline 70b for draining water to the front of the upper rotating body 4 and a drainage pipeline 70c for draining water to the rear of the upper rotating body 4. By switching the switching valve 75 with a control signal from the vehicle controller 45, drainage can be performed from either one of the drainage pipelines 70b or 70c, or from both drainage pipelines 70b and 70c.

[0035] The switching setting of the switching valve 75 can be automatically or manually controlled by the operator by operating the drainage control device 78. The drainage control device 78 allows selection of four different setting states. The first setting state is an automatic control state for the switching valve 75, in which, as described later, the switching valve 75 is automatically switched according to the tilt state of the hydraulic excavator 100 detected by the tilt sensor 72, and water is drained from either the drainage pipe 70b or 70c.

[0036] On the other hand, the second to fourth settings are settings in which the switching valve 75 is manually controlled. The second setting is a setting in which drainage is performed from the drainage pipe 70b. The third setting is a setting in which drainage is performed from the drainage pipe 70c. The fourth setting is a setting in which drainage is performed from both the drainage pipes 70b and 70c.

[0037] Figure 4 illustrates the angles of the drainage pipes 70b and 70c. Figure 4 shows the hydraulic excavator 100 working on a slope. In Figure 4, the fuel cell 21 and drainage pipes 70b and 70c installed on the lower traveling body 3 and the upper rotating body 4 (shown by the dashed line) are shown as part of the hydraulic excavator 100's configuration. When working on a slope, the lower traveling body 3 is usually positioned so that its front-to-back direction coincides with the direction of the slope (left-to-right direction in the illustration), as shown in Figure 4.

[0038] Angle α is the angle of the drainage pipes 70b and 70c with respect to the upper swivel body 4. Drainage pipe 70b extends forward from the upper swivel body 4 with a downward slope of angle α. On the other hand, drainage pipe 70c extends backward from the upper swivel body 4 with a downward slope of angle α. The line indicated by the symbol PH represents the horizontal plane, and angle β is the inclination angle detected by the inclination sensor 72. In this case, the angle θc of drainage pipe 70c with respect to the horizontal plane PH is θc = α + β, and the angle θb of drainage pipe 7b with respect to the horizontal plane PH is θb = β - α. That is, the relationship θc > θb holds. Even when the upper swivel body 4 is rotated from the state shown in Figure 4, the relationship θc > θb is maintained as long as the rotation angle is between 0 and 90 degrees.

[0039] In the example shown in Figure 4, drain pipe 70c is inclined downward with respect to the horizontal plane pH, while drain pipe 70b is inclined upward with respect to the horizontal plane pH. In this case, by draining the generated water from the drain pipe 70c that is inclined downward, reliable drainage of the generated water can be ensured, and the residue of generated water in the drain pipe can be prevented.

[0040] Figure 5 is a flowchart showing an example of the drainage pipe selection operation by the vehicle controller 45. The vehicle controller 45 performs the process shown in the flowchart of Figure 5 at predetermined calculation cycles. In step S10, the vehicle controller 45 determines whether the setting state (drainage setting state) of the drainage operation device 78 is the first setting state (automatic control). If it is the first setting state (automatic control), the process proceeds to step S20; otherwise, the process proceeds to step S25.

[0041] First, the case of proceeding to step S20 (in the case of automatic control) will be described. In step S20, based on the detection information of the inclination sensor 72, the angles θb and θc (see FIG. 4) of the drain pipes 70b and 70c with respect to the horizontal plane PH are estimated.

[0042] In step S30, it is determined whether the angles θb and θc satisfy θb > θc. If it is determined in step S30 that θb > θc, the process proceeds to step S40, and the switching valve 75 is set to the first switching position 75L (see FIG. 3). As a result, the generated water is drained from the drain pipe 70b to the front side of the vehicle body. On the other hand, if it is determined in step S30 that θb > θc is not satisfied, the process proceeds to step S50, and the switching valve 75 is set to the second switching position 75R. As a result, the generated water is drained from the drain pipe 70c to the rear side of the vehicle body.

[0043] On the other hand, the case of proceeding to step S25 when it is determined in step S10 that the setting state (drain setting state) of the drain operation device 78 is not the first setting state (automatic control) will be described. In step S25, it is determined which of the second setting state (front), the third setting state (rear), and the fourth setting state (both) the drain operation device 78 is set to.

[0044] If it is determined in step S25 that the drain operation device 78 is set to the second setting state (front), the process proceeds to step S40, and the switching valve 75 is set to the first switching position 75L. As a result, the generated water is drained from the drain pipe 70b to the front side of the vehicle body.

[0045] If it is determined in step S25 that the drain operation device 78 is set to the third setting state (rear), the process proceeds to step S50, and the switching valve 75 is set to the second switching position 75R. As a result, the generated water is drained from the drain pipe 70c to the rear side of the vehicle body.

[0046] If it is determined in step S25 that the drain operation device 78 is set to the fourth setting state (both), the process proceeds to step S60. In step S60, the switching valve 75 is set to the neutral position 75N, and the generated water is drained from both the drain pipes 70b and 70c.

[0047] When the driver manually operates the drainage operation device 78 to the second to fourth set states to select the drainage pipelines 70b and 70c, the selection of the drainage pipelines can be made by referring not only to the actually visible surrounding environmental situation but also to the surrounding image (drainage environment information) displayed on the display device 77. FIG. 6 is a diagram showing an example of the display information displayed on the display device 77. In the example shown in FIG. 6, the surrounding images (drainage environment information) are displayed in the display areas 771 and 774. An icon 772 representing the hydraulic excavator 100 is displayed in the display area 771 provided at the center of the display screen 770, and the surrounding image 773 of the vehicle body captured by the imaging device 73 is displayed around the icon 772. In the example shown in FIG. 6, the surrounding image 773 of the vehicle body is composed of images of the rear and left and right directions of the vehicle body.

[0048] An icon 775 representing the hydraulic excavator is displayed in the display area 774 as a display representing the inclination information. The numerical value of the inclination angle is displayed in the display area 776 near the icon 775. Further, drainage information 777 indicating the drainage direction is displayed below the icon 775. In the example shown in FIG. 6, the icon 775 indicates that the vehicle body is tilted forward, and the value 5.3° of the inclination angle is displayed in the display area 776. The column of the drainage information 777 is displayed as "Draining forward", and the driver can recognize that the generated water is being drained to the front side of the vehicle body.

[0049] In the case of manual operation, since the driver can select one or both of the drainage pipelines 70b and 70c at his or her discretion, the drainage direction can be selected in consideration of not only the inclination of the vehicle body but also the surrounding situation.

[0050] In the automatic control described above, the system was configured to select only one of the drainage pipes 70b or 70c, but it is also possible to add a state in which drainage is performed from both drainage pipes 70b and 70c. For example, if the tilt angle detected by the tilt sensor 72 is close to 0°, the system may be configured to use both drainage pipes 70b and 70c. Alternatively, the system may be configured such that if both angles θb and θc are downward angles with respect to the horizontal plane, the switching valve 75 is set to the neutral position 75N; if only angle θb is downward angles with respect to the horizontal plane, the switching valve 75 is set to the first switching position 75L; and if only angle θc is downward angles with respect to the horizontal plane, the switching valve 75 is set to the second switching position 75R.

[0051] (Modification) In the above-described embodiment, a switching valve 75 was used to select one or both of the drainage pipes 70b and 70c. However, as shown in Figure 7, the switching valve 75 may be omitted, and the drainage pipes 70b and 70c may be directly connected to the drainage pipe 70a. In this case as well, it is preferable to set the drainage pipes 70b and 70c so that there are no upward slopes in the direction of extension, taking drainage into consideration. In the example shown in Figure 7, similar to the above-described embodiment, the drainage pipes 70b and 70c are configured to have a downward slope in the direction of extension. For example, when working on a sloped area as shown in Figure 4, even with the configuration shown in Figure 7, the drainage direction of one of the drainage pipes (drainage pipe 70c in Figure 4) will always have a downward slope with respect to the horizontal plane PH, so the generated water can be reliably drained.

[0052] The embodiments and modifications of the present invention described above provide the following effects.

[0053] (1) As shown in Figures 1 to 3, 7, etc., in a work machine (hydraulic excavator 100) comprising a fuel cell 21, an electric motor 23 driven by the power generated by the fuel cell 21, and drainage pipes 70a to 70c connected to the fuel cell 21 for draining the water generated by the fuel cell 21, the drainage pipes 70a to 70c have a first drainage pipe (drainage pipe 70b) and a second drainage pipe (drainage pipe 70c) extending from the fuel cell 21 mounting section (upper rotating body 4) to guide the water generated by the fuel cell 1 to the outside of the vehicle, and the first drainage pipe (drainage pipe 70b) and the second drainage pipe (drainage pipe 70c) are arranged to extend from the fuel cell 21 to opposite sides of each other.

[0054] In this way, by providing drainage pipes 70b and 70c that extend downwards in opposite directions, for example, even when the hydraulic excavator 100 is working on a slope as shown in Figure 4, one of the drainage pipes (drainage pipe 70c in the case of Figure 4) can be inclined downwards with respect to the horizontal plane PH. As a result, the water generated by the fuel cell 21 can be drained outside the vehicle body.

[0055] (2) In the above (1), as shown in Figures 1 to 3, 5, etc., the hydraulic excavator 100 is characterized by comprising: a switching valve 75 that switches the destination of the generated water produced by the fuel cell 21 to either a first drainage pipe (drainage pipe 70b) or a second drainage pipe (drainage pipe 70c); a tilt sensor 72 that detects the tilt state of the machine, which is the tilt information (tilt angle); and a controller (machine controller 45) that controls the switching state of the switching valve 75 based on the tilt information (tilt angle) detected by the tilt sensor 72.

[0056] In this way, the vehicle controller 45 selects the drainage pipes 70b and 70c based on the detected tilt angle, allowing the operator to perform the work without having to worry about the drainage direction of the work machine.

[0057] (3) In the above (2), as shown in Figures 3 to 5, the vehicle body controller 45 controls the switching state of the switching valve 75 so that the generated water is drained into the drain pipe with a greater downward slope in the angle (θb, θc) with respect to the horizontal plane PH, among the first drain pipe (drain pipe 70b) and the second drain pipe (drain pipe 70c), based on the vehicle body tilt information (tilt angle) detected by the tilt sensor 72, that is, so that the water is drained from the drain pipe 70c with an angle θc (>θb).

[0058] Conventionally, work machines such as hydraulic excavators 100 are generally equipped with tilt sensors (e.g., vehicle IMU) for vehicle stability management. By using these tilt sensors to select and control the drainage pipes 70b and 70c, it is possible to automatically control the switching valve 75 while keeping costs down.

[0059] (4) In the above (2), as shown in Figures 1 to 3, 5, etc., the hydraulic excavator 100 is further provided with a switching operation selection unit (drainage operation device 78) that allows manual operation to select one of a first switching state (first switching position 75L) and a second switching state (second switching position 75R), and the vehicle body controller 45 controls the switching valve 75 to the switching state selected by the drainage operation device 78, taking priority over the control of the switching valve 75 based on the vehicle body tilt information (tilt angle).

[0060] Thus, since the control of the switching valve 75 by the drainage operating device 78 takes precedence over the control of the switching valve 75 based on the vehicle body tilt information (tilt angle) (the automatic control described above), even during control based on the vehicle body tilt information (tilt angle), the operator can change to the desired drainage direction by operating the drainage operating device 78. Therefore, the operator can select a drainage pipeline while also considering conditions other than the tilt angle of the hydraulic excavator 100.

[0061] (5) In (1) above, as shown in Figures 3 and 5, the hydraulic excavator 100 includes a switching valve 75 having a first switching state (first switching position 75L) that directs the water generated from the fuel cell 21 to a first drainage pipe (drainage pipe 70b) and a second switching state (second switching position 75R) that directs the water generated from the fuel cell 21 to a second drainage pipe (drainage pipe 70c), a switching operation selection unit (drainage operation device 78) that selects one of the first switching state (first switching position 75L) and the second switching state (second switching position 75R) by manual operation, and a vehicle controller 45 that controls the switching valve 75 to the switching state selected by the drainage operation device 78. In addition to the effects described in (1) above, the operator can select a more appropriate drainage direction by operating the drainage operation device 78, taking into account the tilt state of the hydraulic excavator 100 and the surrounding environment.

[0062] (6) In (5) above, as shown in Figure 6, the hydraulic excavator 100 further includes an imaging device 73 that captures an image 773 of the area around the hydraulic excavator 100, and a display device 77 that simultaneously displays the image 773 of the area around the vehicle and the switching status of the switching valve 75 (drainage information 777). By referring to the image 773 of the area around the vehicle and the drainage information 777 indicating the switching status of the switching valve 75 displayed on the display device 77, the operator can learn more about the drainage environment and easily determine the appropriate drainage direction for the generated water.

[0063] 1a, 1b... Tracks, 2... Front equipment, 3... Lower running body, 4... Upper rotating body (mounting section), 8... Driver's cab, 9... Machine room, 21... Fuel cell, 23... Electric motor, 45... Vehicle controller, 50... Hydrogen tank, 70... Drainage pipeline system, 70b... Drainage pipeline (first drainage pipeline), 70c... Drainage pipeline (second drainage pipeline), 72... Inclination sensor, 73... Imaging device, 75... Switching valve, 75L... First switching position, 75N... Neutral position, 75R... Second switching position, 77... Display device, 78... Drainage operation device (switching operation selection section), 100... Hydraulic excavator, 773... Image of the area around the vehicle, 777... Drainage information, PH... Horizontal plane

Claims

1. A work machine comprising a fuel cell, an electric motor driven by the power generated by the fuel cell, and a drainage pipe connected to the fuel cell for draining the water generated by the fuel cell, wherein the drainage pipe has a first drainage pipe and a second drainage pipe for leading the water generated to the outside of the vehicle, and the first drainage pipe and the second drainage pipe are arranged to extend from the fuel cell on opposite sides.

2. A work machine according to claim 1, comprising: a switching valve for switching the destination of the generated water produced by the fuel cell to either the first drainage pipe or the second drainage pipe; a tilt sensor for detecting vehicle tilt information, which is the tilt state of the machine itself; and a controller for controlling the switching state of the switching valve based on the vehicle tilt information detected by the tilt sensor.

3. The work machine according to claim 2, wherein the controller controls the switching state of the switching valve based on the vehicle body tilt information detected by the tilt sensor, so that the generated water is drained into the drain pipe among the first drain pipe and the second drain pipe that has a greater downward slope angle with respect to the horizontal plane.

4. A work machine according to claim 2, further comprising a switching operation selection unit for selecting one of the first switching state and the second switching state, wherein the controller controls the switching valve to the switching state selected by the switching operation selection unit, in priority to the control of the switching valve based on the vehicle body tilt information, when a selection operation is performed by the switching operation selection unit.

5. A work machine according to claim 1, comprising: a switching valve having a first switching state for guiding the generated water from the fuel cell to a first drainage pipe and a second switching state for guiding the generated water from the fuel cell to a second drainage pipe; a switching operation selection unit for selecting one of the first switching state and the second switching state; and a controller for controlling the switching valve to the switching state selected by the switching operation selection unit.

6. A work machine according to claim 5, further comprising: an imaging device for capturing an image of the area around the work machine's body; and a display device for simultaneously displaying the image of the area around the body and the switching state of the switching valve.

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