Work machine

Abstract

To provide a work machine which is less likely to cause erroneous mixing of types of cooling water at cooling water refilling work in maintenance works.SOLUTION: A work machine comprises: an electric motor 23 as a power source; a fuel cell 21 for generating electric power to be supplied to the electric motor 23; a water supply port 79a for supplying water to a fuel cell cooling system that circulates a first cooling water for cooling the fuel cell 21; and water supply ports 84a, 85a for supplying water to an electric equipment cooling circuit that circulates a second cooling water for cooling the electric motor 23, and to an auxiliary engine cooling circuit. The water supply port 79a is arranged on one side of the own machine while the water supply ports 84a, 85a being arranged on the other side of the own machine.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a work machine, and more particularly to a work machine that is equipped with a fuel cell and is driven by electric power generated by the fuel cell. [Background technology]

[0002] Generally, fuel cells generate electricity from hydrogen and oxygen (air), but at the same time, they also generate heat, making cooling necessary. A typical cooling system is made up of a cooling water circuit through which cooling water passes, and a radiator, but in high-voltage fuel cells, there is a risk of electrical leakage through the cooling water. General cooling water contains additives such as rust inhibitors and pH adjusters, so it cannot be used with fuel cells. For this reason, highly insulating cooling water is used as the cooling water for fuel cells, and an ion exchanger is installed in the cooling circuit to prevent the concentration of ions dissolved in the piping from becoming too high.

[0003] Patent Document 1 discloses a fuel cell temperature control system that adjusts the temperature of an FC stack by circulating a coolant. The fuel cell temperature control system includes a coolant flow path through which coolant with ion exchange resin particles added beforehand flows, an ion exchanger that removes ions that have dissolved in the coolant, and a radiator that cools the coolant. Only the amount of ion exchange resin particles added to the coolant is necessary to remove ions that dissolve in the initial stage from parts that come into contact with the coolant (such as the radiator), and ions that are generated over time are removed by the ion exchanger. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-186647 A Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, a work machine equipped with a fuel cell requires a cooling system for cooling electrically-driven devices such as an electric motor, in addition to a cooling system for the fuel cell. Electric devices such as electric motors generate relatively little heat energy, so the distance between the cooling unit and heat generating unit of each device can be kept relatively long while considering electrical safety, and there is little risk of electrical leakage even if ordinary cooling water is used. On the other hand, fuel cells generate a lot of heat, so higher cooling performance and miniaturization are required, and therefore the distance between the cooling unit and heat generating unit must be as short as possible. Therefore, as mentioned above, it is necessary to use highly insulating cooling water to achieve both electrical safety and safety. Highly insulating cooling water is very expensive, and it is difficult from a cost perspective to standardize on high-insulating cooling water. Therefore, two types of cooling water are mixed in the cooling system of a work machine equipped with a fuel cell. Therefore, when refilling the cooling water during maintenance, there is a risk of using the wrong type of cooling water. An object of the present invention is to provide a work machine which is less likely to replenish the wrong type of cooling water when performing work such as replenishing cooling water during maintenance or the like. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides a work machine comprising an electric motor as a power source, a fuel cell that generates electricity to be supplied to the electric motor, a first water inlet for supplying water to a first cooling circuit that circulates a first cooling water that cools the fuel cell, and a second water inlet for supplying water to a second cooling circuit that circulates a second cooling water that cools the electric motor, the first water inlet being provided on one side of the work machine and the second water inlet being provided on the other side of the work machine.In this case, a work machine can be provided that is less likely to replenish the wrong type of cooling water when performing work such as refilling cooling water during maintenance, etc.

[0007] Here, the first cooling circuit is provided with a first heat exchanger, the second cooling circuit is provided with a second heat exchanger, the first heat exchanger is provided on one side of the vehicle, and the second heat exchanger is provided on the other side of the vehicle facing the first heat exchanger. In this case, it is easier to provide the first water supply port and the second water supply port at positions on opposite sides of the vehicle body. In addition, the cooling system may include a first cooling fan for cooling the first heat exchanger and a second cooling fan for cooling the second heat exchanger, and the first and second cooling fans may be disposed opposite each other, thereby suppressing recirculation that deteriorates the cooling performance. Furthermore, the first water inlet and the second water inlet can be disposed along the left-right direction of the vehicle, in which case water inlets can be provided separately on the left and right sides of the vehicle body. Furthermore, the vehicle may have a driver's cab, and the first water supply port may be provided on the driver's cab side in the left-right direction of the vehicle, which makes maintenance of the fuel cell ion exchanger easier. The first water inlet and the second water inlet can be disposed along the front-rear direction of the vehicle, in which case the water inlet can be provided separately in the front-rear direction of the vehicle body. Furthermore, the water inlet cover covering the first water inlet and the water inlet cover covering the second water inlet can be separate members, which makes it even less likely that the wrong type of cooling water will be refilled. Effect of the Invention

[0008] According to the present invention, a work machine can be provided in which, when performing work such as refilling cooling water during maintenance, it is unlikely that the wrong type of cooling water will be refilled. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing the overall configuration of a work machine in an embodiment of the present invention. [Diagram 2] FIG. 1 is a diagram showing a system configuration of a hydraulic excavator. [Diagram 3]1 is an explanatory diagram of a fuel cell cooling system for a work machine according to an embodiment of the present invention; [Figure 4] FIG. 2 is a top view of a rotating body of the hydraulic excavator according to the embodiment. [Diagram 5] FIG. 2 is a left side view of a rotating body of the hydraulic excavator according to the embodiment. [Figure 6] FIG. 2 is a right side view of a rotating body of the hydraulic excavator according to the embodiment. [Figure 7] FIG. 11 is a top view of a rotating body of a hydraulic excavator in a modified example. [Figure 8] FIG. 11 is a top view of a rotating body of a hydraulic excavator in a modified example. [Figure 9] FIG. 11 is a top view of a rotating body of a hydraulic excavator in a modified example. [Figure 10] FIG. 11 is a left side view of a rotating body of a hydraulic excavator in a modified example. [Figure 11] FIG. 11 is a right side view of a rotating body of the hydraulic excavator in a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0011] <Explanation of the overall configuration of the work machine> FIG. 1 is a diagram showing the overall configuration of a work machine in this embodiment. The working machine shown in the figure is a hydraulic excavator 100. However, the working machine is not limited to this, and may be a construction machine such as a wheel loader, a bulldozer, a crane truck, etc. Furthermore, the working machine may be an agricultural machine such as a felling machine, a timber processing machine, a tractor, a forest work vehicle, a timber collector, etc.

[0012] The hydraulic excavator 100 comprises a running body 3 having a pair of left and right tracks 1, 2, a rotating body 4 mounted on the running body 3 and serving as an example of the excavator's own machine, a boom 5 rotatably connected to one end of the rotating body 4 with a pin, an arm 6 rotatably connected to one end of the boom 5 with a pin, and a bucket 7 rotatably connected to one end of the arm 6 with a pin. Furthermore, the hydraulic excavator 100 is equipped with a driver's cab 8 provided on the rotating body 4, a machine room 9 that houses an electric motor 23 and a main pump 31 (see FIG. 2) described below, a counterweight 10, travel motors 11, 12 that drive the tracks 1, 2, a pair of left and right boom cylinders 14, 15 that drive the boom 5, an arm cylinder 16 that drives the arm 6, and a bucket cylinder 17 that drives the bucket 7. At this time, the main working arm corresponds to the boom 5, arm 6 and bucket 7, and the posture of these working arm mechanisms is determined by the extension and contraction of the boom cylinders 14, 15, arm cylinder 16 and bucket cylinder 17, respectively.

[0013] FIG. 2 is a diagram showing the system configuration of the hydraulic excavator 100. Since the traveling motors 11, 12 and the swing motor 13 all have the same configuration as hydraulic motors, the following description will take the swing motor 13 as an example, and the description of the traveling motors 11, 12 will be omitted. Similarly, since the boom cylinders 14, 15, the arm cylinder 16, and the bucket cylinder 17 all have the same configuration as hydraulic cylinders, the following description will take the arm cylinder 16 as an example, and the description of the boom cylinders 14, 15, and the bucket cylinder 17 will be omitted. Therefore, Fig. 2 shows only the hydraulic circuit configuration related to the arm cylinder 16 and the swing motor 13, and does not show the other hydraulic actuators.

[0014] The hydraulic excavator 100 has, as its system configuration, an electric power circuit 20 that operates the electric equipment, a hydraulic circuit 30 that generates hydraulic pressure, an operation system 40 that performs operations to control the operation of the electric power circuit 20 and the hydraulic circuit 30, a hydrogen tank 50 that stores hydrogen, a low-voltage circuit 60 that is a low-voltage electric power circuit, and a cooling system 70 that cools the fuel cell and the like.

[0015] The hydraulic circuit 30 includes a main pump 31, a pilot pump 32, a hydraulic oil tank 33 for storing hydraulic oil, a rotation motor 13 for driving the rotating body 4, a first directional control valve 34 for controlling the flow of hydraulic oil related to the rotation motor 13, and a second directional control valve 35 for controlling the flow of hydraulic oil related to the arm cylinder 16. The main pump 31 is a variable displacement hydraulic pump driven by the electric motor 23. This main pump 31 draws hydraulic oil from a hydraulic oil tank 33, and supplies the hydraulic oil to the swing motor 13 and the arm cylinder 16 via a first directional control valve 34 and a second directional control valve 35. Note that in this embodiment, a variable displacement hydraulic pump is used for the main pump 31, but this is not limiting, and a fixed displacement hydraulic pump may also be used. The pilot pump 32 is a fixed displacement hydraulic pump driven by the electric motor 23. This pilot pump 32 draws hydraulic oil from a hydraulic oil tank 33, and supplies it to a pair of pressure receiving chambers 34A, 34B of the first directional control valve 34 and a pair of pressure receiving chambers 35A, 35B of the second directional control valve 35, respectively. The hydraulic circuit 30 further includes a main relief valve 36 that determines the upper limit of the discharge pressure of the main pump 31, a pilot relief valve 37 that determines 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 and the hydraulic oil tank 33.

[0016] In the operator's cab 8, an operation system 40 is provided, which includes an operation mode selection switch 41, a motor control dial 42 for setting the rotation speed of the electric motor 23 described below, operation levers 43A, 43B, a vehicle controller 45, and the like. The operation levers 43A, 43B correspond to the respective swing motors 13 and arm cylinders 16, and may be, for example, electric levers that output an electric operation signal (lever signal Lv) according to the operation amount. The vehicle body controller 45 receives the lever signal Lv of the operation levers 43A, 43B, and outputs a command signal according to the lever signal Lv to the solenoid proportional valves 34a, 34b and the solenoid proportional valves 35a, 35b, thereby controlling the switching direction and stroke amount of the first directional control valve 34 and the second directional control valve 35. At the same time, the controller outputs a command signal according to the lever signal Lv, the pump discharge pressure sensor 31S, the electric motor rotation speed sensor (not shown), etc., to the regulator 31R of the main pump 31, thereby controlling the pump capacity (discharge flow rate). With this configuration, the operation levers 43A, 43B cause each hydraulic actuator to perform a desired operation.

[0017] The first directional control valve 34 is a center bypass type directional control valve, and has a first switching position 34L for rotating the swing motor 13 forward, a neutral position 34N for communicating the main pump 31 with the hydraulic oil tank 33 to return hydraulic oil directly to the hydraulic oil tank 33, and a second switching position 34R for rotating the swing motor 13 backward. The first directional control valve 34 is configured to be switched to any one of the first switching position 34L, the neutral position 34N, and the second switching position 34R by an internal spool stroking in response to pilot pressures acting on a pair of pressure receiving chambers 34A, 34B, respectively. This controls the flow rate and direction (flow) of hydraulic oil supplied from the main pump 31 to the swing motor 13.

[0018] The second directional control valve 35 is a center bypass type directional control valve similar to the first directional control valve 34, and has a first switching position 35L for retracting the rod 16C of the arm cylinder 16, a neutral position 35N for communicating the main pump 31 with the hydraulic oil tank 33 to return hydraulic oil directly to the hydraulic oil tank 33, and a second switching position 35R for extending the rod 16C of the arm cylinder 16. The second directional control valve 35 is configured to be switched to any one of the first switching position 35L, the neutral position 35N, and the second switching position 35R by the stroke of an internal spool in response to the pilot pressures acting on the pair of pressure receiving chambers 35A and 35B, respectively, similar to the first directional control valve 34. This controls the flow rate and direction (flow) of hydraulic oil supplied from the main pump 31 to the arm cylinder 16.

[0019] The on-off valve 38 is an electromagnetic proportional valve whose opening is adjusted in proportion to the magnitude of a command current, and whose opening area is adjusted in proportion to the magnitude of a command current from the vehicle body controller 45. Therefore, even when the valve is not in operation or the load on the hydraulic actuator is small, the pressure of the main pump 31 can be freely set. The hydraulic circuit 30 is provided with an oil cooler 81 for cooling the hydraulic oil, and the hydraulic oil is appropriately cooled by an electric fan (not shown).

[0020] The power circuit 20 includes a fuel cell 21, an inverter 22, a secondary battery 25, a boost converter 28, and a high-voltage DCDC converter 29, and is connected to an electric motor 23 and various electric accessories (not shown). The hydraulic excavator 100 operates by driving the main pump 31 with the electric motor 23. In other words, the electric motor 23 is a power source. In this case, the electric motor 23 is driven using electric power generated by the fuel cell 21 to which hydrogen is supplied from the hydrogen tank 50. In other words, the fuel cell 21 generates electric power to be supplied to the electric motor 23.

[0021] 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., 650 V). However, the voltage is boosted by a boost converter 28 provided in the fuel cell 21 to correspond to the rated voltage of the electric motor 23. The inverter 22 converts the DC voltage (system voltage) boosted by the boost converter 28 into an AC voltage, and controls the rotation speed of the electric motor 23. The high-voltage DCDC converter 29 is a bidirectional voltage converter that 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. The secondary battery 25 can store electricity using surplus power generated by the fuel cell 21, and also functions as a power source that supplies power to loads including the electric motor 23. The secondary battery 25 may be any chargeable and dischargeable power storage device, and may be, for example, a lithium ion battery or a nickel-metal hydride battery. The secondary battery 25 is provided with a battery sensor (not shown) for detecting the operating state of the secondary battery 25, such as the voltage, current, and remaining capacity (SOC (State Of Charge)).

[0022] The vehicle body controller 45 is a higher-level controller that controls 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, the lower-level controllers (fuel cell controller 47, battery controller 46), the low-voltage DCDC converter 63, the inverter 22, etc. These controllers are connected to a low-voltage circuit 60 (e.g., 24 V) including a lead battery 61. A low-voltage DC-DC converter 63 is connected to the low-voltage circuit 60, and generates a stable low voltage using power from the power circuit 20. The lead battery 61 is connected to the low voltage circuit 60 via a disconnect switch 62, and is configured to be able to cut off the system power supply source for the purposes of preventing the lead battery from wearing out, preventing theft, improving safety during vehicle maintenance, etc. Furthermore, a key switch 64 is connected to the vehicle controller 45, and starts and stops the vehicle operations.

[0023] The hydrogen tank 50 stores hydrogen to be used in the fuel cell 21. The hydrogen tank 50 is a pressure-resistant container made of, for example, metal or resin. The hydrogen tank 50 may also include a compressor that adjusts the hydrogen to an appropriate pressure, a precooler that cools the hydrogen, a hydrogen valve that adjusts the flow rate of the hydrogen, and the like.

[0024] 3(a) to (c) are explanatory diagrams of a cooling system 70 for a work machine according to the present embodiment. The cooling system 70 is composed of a fuel cell cooling system 70a shown in Figure 3(a), an electric equipment cooling system 70b shown in Figure 3(b), and a fuel cell auxiliary cooling system 70c shown in Figure 3(c).

[0025] As shown in FIG. 3(a), the fuel cell cooling system 70a includes a fuel cell cooling circuit 71a which is a circulation path for fuel cell cooling water 90a, a fuel cell (FC) radiator 72 which is a heat exchanger, an electric fan 73a which cools the fuel cell cooling water 90a in the fuel cell radiator 72, an electric water pump 74a which pumps out the fuel cell cooling water 90a, a fuel cell ion exchanger 75 which removes ions from the fuel cell cooling water 90a, and water temperature sensors 76a, 77a, 78 which measure the temperature of the fuel cell cooling water 90a. In this embodiment, the fuel cell cooling circuit 71a is an example of a first cooling circuit which circulates the first cooling water which cools the fuel cell 21. Here, the fuel cell cooling water 90a is an example of the first cooling water. The fuel cell radiator 72 is an example of a first heat exchanger provided in the first cooling circuit, and the electric fan 73a is an example of a first cooling fan which cools the first heat exchanger.

[0026] The fuel cell cooling system 70a is connected to the fuel cell 21 and the fuel cell cooling circuit 71a, and the fuel cell cooling water 90a is circulated by an electric water pump 74a. A fuel cell radiator 72 is provided in the circulation path, and the fuel cell cooling water 90a is cooled by an electric fan 73a. Furthermore, in order to maintain the insulation of the fuel cell cooling circuit 71a, a fuel cell ion exchanger 75 is provided to prevent the ion concentration in the fuel cell cooling water 90a from becoming high. The fuel cell cooling system 70a is controlled by the vehicle controller 45 based on sensor information from water temperature sensors 76a, 77a, and 78 provided in the circulation path and a temperature sensor (not shown) in the fuel cell 21. The water temperature sensor 76a measures the outlet temperature of the fuel cell cooling water 90a that has cooled the fuel cell 21. The rotation speed of the electric fan 73a is mainly controlled based on the temperature measured by the water temperature sensor 76a. This allows the amount of airflow to the fuel cell radiator 72 to be adjusted. The water temperature sensor 77a measures the outlet temperature of the fuel cell cooling water 90a cooled by the fuel cell radiator 72. The temperature measured by the water temperature sensor 77a makes it possible to see the effect of the bypass flow path that does not pass through the fuel cell radiator 72 but passes through the fuel cell ion exchanger 75. The water temperature sensor 78 measures the inlet temperature of the fuel cell cooling water 90a flowing into the fuel cell 21. The rotation speed of the electric water pump 74a is mainly controlled based on the temperature measured by the water temperature sensor 78. This makes it possible to adjust the amount of fuel cell cooling water 90a circulating through the fuel cell cooling circuit 71a. In addition, a fuel cell supply tank 79 (see FIG. 4) is provided with a water supply port 79a for supplying fuel cell cooling water 90a to the fuel cell cooling circuit 71a. The water supply port 79a is an example of a first water supply port for supplying water to the fuel cell cooling circuit 71a, which circulates first cooling water that cools the fuel cell 21.

[0027] As shown in FIG. 3(b), the electric device cooling system 70b includes an electric device cooling circuit 71b which is a circulation path for the electric device cooling water 90b, an electric device radiator 82 which is a heat exchanger, an electric fan 73b which cools the electric device cooling water 90b in the electric device radiator 82, an electric water pump 74b which pumps out the electric device cooling water 90b, and water temperature sensors 76b, 77b which measure the temperature of the electric device cooling water 90b. In this embodiment, the electric device cooling circuit 71b is an example of a second cooling circuit which circulates the cooling water which cools the electric motor 23. Here, the electric device cooling water 90b is an example of the second cooling water. The electric device radiator 82 is an example of a second heat exchanger provided in the second cooling circuit, and the electric fan 73b is an example of a second cooling fan which cools the second heat exchanger.

[0028] The inverter 22, the electric motor 23, the secondary battery 25, the low-voltage DCDC converter 63, and the electric equipment cooling circuit 71b are connected to the electric equipment cooling system 70b, and an electric water pump 74b circulates electric equipment cooling water 90b. An electric equipment radiator 82 is provided in the circulation path, and an electric fan 73b cools the electric equipment cooling water 90b. The electric equipment cooling system 70b is controlled by the vehicle body controller 45 based on sensor information from water temperature sensors 76b, 77b provided in the circulation path and temperature sensors (not shown) in each of the electric equipment (22, 23, 25, 63). In addition, an electric device supply tank 84 (see FIG. 4) having a water supply port 84a for supplying electric device cooling water 90b to the electric device cooling circuit 71b is provided. The water supply port 84a is an example of a second water supply port for supplying water to the electric device cooling circuit 71b that circulates second cooling water for cooling the electric motor 23.

[0029] As shown in FIG. 3(c), the fuel cell auxiliary cooling system 70c includes an auxiliary cooling circuit 71c which is a circulation path for the auxiliary cooling water 90c, an auxiliary radiator 83 which is a heat exchanger, an electric fan 73c which cools the auxiliary cooling water 90c in the auxiliary radiator 83, an electric water pump 74c which pumps out the auxiliary cooling water 90c, and water temperature sensors 76c, 77c which measure the temperature of the auxiliary cooling water 90c. In this embodiment, the auxiliary cooling circuit 71c is also an example of the second cooling circuit. Here, the auxiliary cooling water 90c is also an example of the second cooling water. The auxiliary radiator 83 is also an example of the second heat exchanger, and the electric fan 73c is also an example of the second cooling fan.

[0030] The fuel cell auxiliary cooling system 70c is connected to the boost converter 28, the high-voltage DCDC converter 29, and the auxiliary cooling circuit 71c, and circulates auxiliary cooling water 90c by an electric water pump 74c. An auxiliary radiator 83 is provided in the circulation path, and the auxiliary cooling water 90c is cooled by an electric fan 73c. ​​The fuel cell auxiliary cooling system 70c is controlled by the vehicle controller 45 based on sensor information from water temperature sensors 76c, 77c provided in the circulation path and temperature sensors (not shown) in the fuel cell auxiliary devices (28, 29). In addition, an auxiliary equipment supply tank 85 (see FIG. 4) having a water supply port 85a for supplying auxiliary equipment cooling water 90c to the auxiliary equipment cooling circuit 71c is provided. The water supply port 85a is also an example of a second water supply port.

[0031] Fig. 4 is a top view of the revolving body 4 of the hydraulic excavator 100 of this embodiment. Fig. 5 is a left side view of the revolving body 4 of the hydraulic excavator 100 of this embodiment. Fig. 6 is a right side view of the revolving body 4 of the hydraulic excavator 100 of this embodiment. In Figs. 4 to 6, covers are removed to allow components to be seen, for ease of explanation of this embodiment.

[0032] The rotating body 4 is provided with a fuel cell 21, an inverter 22 electrically connected to the fuel cell 21, and an electric motor 23. The electric motor 23 and a main pump 31 are mechanically linked, and hydraulic oil discharged from the main pump 31 is distributed to hydraulic actuators (the rotating motor 13, the arm cylinder 16, etc.) in response to the operation of the operator, thereby enabling the hydraulic excavator 100 to perform the desired operation. The rotating body 4 is further provided with a secondary battery 25, and the fuel cell 21, the inverter 22, and the secondary battery 25 are connected by high-voltage cables (not shown) to form a power circuit 20.

[0033] A hydrogen tank 50 filled with high-pressure hydrogen is installed at the rear of the rotating body 4 and in front of the counterweight 10. With this configuration, the counterweight 10 protects the hydrogen tank 50 against object impacts from behind. The hydrogen tank 50 and fuel cell 21 are connected by hydrogen piping (not shown), making it possible to supply hydrogen to the fuel cell 21.

[0034] An oil cooler 81, an electric device radiator 82, and an auxiliary device radiator 83 are installed on the right outer edge (second direction) of the rotating body 4 behind the hydraulic oil tank 33. Meanwhile, a fuel cell radiator 72 for cooling the fuel cell 21 is installed on the left outer edge (first direction) of the rotating body 4 behind the cab 8. Here, the fuel cell radiator 72 is configured with three units as shown in FIG. 5 because high cooling performance is required, but the number is not limited as long as the cooling performance is satisfied. In addition, six electric fans 73a for cooling the fuel cell cooling water in the fuel cell radiator 72 are provided as shown in FIG. 5, but the number is not limited as long as the cooling performance is similarly satisfied. The fuel cell radiator 72 is connected to the fuel cell cooling circuit 71a and cools the fuel cell cooling water 90a circulating therethrough. Furthermore, a fuel cell supply tank 79 that supplies the fuel cell cooling circuit 71a with fuel cell cooling water 90a is provided near (in the first direction) the fuel cell radiator 72. The fuel cell supply tank 79 is provided with a water supply port 79a.

[0035] The oil cooler 81 is connected to the hydraulic circuit 30 including the main pump 31, the hydraulic oil tank 33, etc., and cools the hydraulic oil. The electric device radiator 82 is connected to the electric device cooling circuit 71b and cools the electric device cooling water 90b circulating therethrough. An electric device supply tank 84 that supplies the electric device cooling circuit 71b with the electric device cooling water 90b is provided near (in the second direction) the electric device radiator 82. The electric device supply tank 84 is provided with a water supply port 84a. The auxiliary equipment radiator 83 is connected to the fuel cell auxiliary equipment cooling system 70c and cools the auxiliary equipment cooling water 90c circulating therethrough. An auxiliary equipment supply tank 85 that supplies the auxiliary equipment cooling water 90c to the fuel cell auxiliary equipment cooling system 70c is provided near (in the second direction) the auxiliary equipment radiator 83. The auxiliary equipment supply tank 85 is provided with a water supply port 85a. The oil cooler 81, the radiator 82 for electric equipment, and the radiator 83 for auxiliary equipment are each provided with an electric fan 81F, an electric fan 73b, and an electric fan 73c. ​​As shown in Fig. 6, two electric fans 81F and two electric fans 73b are provided. Also, as shown in Fig. 6, one electric fan 73c is provided.

[0036] Returning to Fig. 2, the operation of the system in this embodiment will be described. When the driver turns on the key switch 64 in the driver's cab 8, the vehicle body controller 45 is started. The vehicle body controller 45 starts up the inverter 22, the low-voltage DCDC converter 63, the battery controller 46, and the fuel cell controller 47, and further, the battery controller 46 starts up the secondary battery 25 and the high-voltage DCDC converter 29, while the fuel cell controller 47 starts up the fuel cell 21, the boost converter 28, and a hydrogen valve (not shown) connected to the hydrogen tank 50. The vehicle controller 45 starts power generation by the fuel cell 21, driving of the electric motor 23, control of the hydraulic circuit 30, etc. according to the settings of the work mode selection switch 41, the motor control dial 42, and the lever signal Lv of the operation levers 43A, 43B. On the other hand, when the driver turns off the key switch 64 in the driver's cab 8, the vehicle body controller 45 stops the inverter 22, thereby stopping the electric motor 23. Next, the fuel cell controller 47 executes a purge process to discharge moisture remaining inside the fuel cell 21 and in the connecting piping to the outside of the vehicle.

[0037] The purging process requires the fuel cell to generate electricity, and not only the fuel system but also devices related to charging and consuming the generated electricity are operated. In detail, the fuel cell 21 generates electricity using the fuel cell 21, the hydrogen tank 50, the boost converter 28, and the fuel cell controller 47. At this time, the amount of air required for reacting hydrogen is intentionally reduced, and the heat exhausted from the fuel cell 21 is increased, so that moisture remaining inside the fuel cell 21 and in the connecting pipes is discharged to the outside of the vehicle. The generated electricity generated by the purging process can be charged into the secondary battery 25 via the power circuit 20, but since the fuel cell cooling system 70a needs to be started, at least a part of the generated electricity generated by the fuel cell 21 during the purging process is used to drive the electric fan 73a and the electric water pump 74a of the fuel cell cooling system 70a via the low-voltage DCDC converter 63 and the low-voltage circuit 60. In addition, the electric fan 73a and the electric water pump 74a of the fuel cell cooling system 70a are driven until the purging process is completed.

[0038] Therefore, since the electric fan 73a and the electric water pump 74a of the fuel cell cooling system 70a are driven while the purging process is being performed, the driver can recognize that the purging process is being performed when he or she leaves the cab 8 by the operating sounds of the electric fan 73a and the electric water pump 74a that cool the fuel cell radiator 72 located behind the cab 8. Note that the operating sound of the electric fan 73a is particularly loud, and is therefore effective in making the driver recognize that the purging process is being performed. This makes it possible to prevent the driver from interrupting the purging process by turning off the disconnect switch 62.

[0039] Once the purging process has been completed and a series of shutdown processes have been completed, maintenance can be performed, one example of which is the replenishment of cooling water. The cooling water in the work machine of this embodiment includes fuel cell cooling water 90a, electrically-operated equipment cooling water 90b, and auxiliary equipment cooling water 90c. The fuel cell cooling water 90a is highly insulating cooling water, and is a different type of cooling water from the electrically-operated equipment cooling water 90b and the auxiliary equipment cooling water 90c, which use general cooling water. Note that the same cooling water can be used for the electrically-operated equipment cooling water 90b and the auxiliary equipment cooling water 90c. The fuel cell supply tank 79, which supplies fuel cell cooling water 90a, is provided near the fuel cell radiator 72 (first direction), while the electric equipment supply tank 84, which supplies electric equipment cooling water 90b, and the auxiliary equipment supply tank 85, which supplies auxiliary equipment cooling water 90c, are provided near the electric equipment radiator 82 and the auxiliary equipment radiator 83 (second direction).

[0040] In this case, water supply port 79a of fuel cell supply tank 79 is provided on one side of the vehicle, and water supply port 84a of electric equipment supply tank 84 and water supply port 85a of auxiliary equipment supply tank 85 are provided on the other side of the vehicle. In the embodiment of Fig. 4, water supply port 79a, water supply port 84a, and water supply port 85a are arranged along the left-right direction of the vehicle.

[0041] With this configuration, the fuel cell supply tank 79, which supplies cooling water 90a for the fuel cell, is positioned separately to the left and right of the device from the electric equipment supply tank 84 and the auxiliary equipment supply tank 85, which supply general cooling water, making it possible to reliably maintain the insulation of the fuel cell without making any mistakes in the type of cooling water.

[0042] In the embodiment shown in FIG. 4, the water supply port 79a is provided at a position on the driver's cab 8 side in the left-right direction of the vehicle. The fuel cell ion exchanger 75 is accordingly provided at a position on the driver's cab 8 side. The fuel cell ion exchanger 75 requires frequent maintenance. With this configuration, the driver can more easily maintain the fuel cell ion exchanger 75 after leaving the driver's seat, improving convenience.

[0043] The fuel cell radiator 72 is provided on one side of the vehicle, and the electric device radiator 82 and the auxiliary device radiator 83 are provided on the other side of the vehicle, facing the fuel cell radiator 72. This can also be said to mean that the electric fan 73a, the electric fan 73b, and the electric fan 73c are arranged opposite each other. This prevents recirculation, in which hot air downstream of each radiator flows around to the upstream of the other radiator, deteriorating the cooling performance. In other words, the electric device radiator 82, the auxiliary device radiator 83, and the electric fan 73b and the electric fan 73c that cool them are arranged on the other side of the revolving body 4, facing the fuel cell radiator 72 across the fuel cell 21. These electric fans 73b and 73c take in outside air from the other side of the revolving body 4 and send it to the fuel cell 21 side. Meanwhile, the electric fan 73a that cools the fuel cell radiator 72 takes in outside air from one side of the rotating body 4 and sends it out towards the fuel cell 21. As a result, the hot air sent out from each radiator collides near the center of the rotating body 4, changes direction towards the counterweight 10, and is discharged from the rear of the rotating body 4. This makes it less likely that recirculation will occur, which would cause the hot air downstream of each radiator to flow around to the upstream of other radiators and deteriorate cooling performance.

[0044] <Modification> In the above example, the water supply port 79a of the fuel cell supply tank 79 is provided on one side of the vehicle along the left-right direction of the vehicle, and the water supply ports 84a, 85a of the electric equipment supply tank 84 and the auxiliary equipment supply tank 85 are provided on the other side of the vehicle, but they may be arranged along the front-to-rear direction of the vehicle as long as they are provided on opposite sides of the vehicle.

[0045] 7 to 11 are diagrams showing a case in which a water supply port 79a of a fuel cell supply tank 79 is provided on one side of the vehicle, and a water supply port 86a of a supply tank 86 that also serves as an electric equipment supply tank 84 and an auxiliary equipment supply tank 85 is provided on the other side of the vehicle, along the front-to-rear direction of the vehicle. Figs. 7 to 9 are top views of the revolving body 4 of a hydraulic excavator 100 in a modified example. Fig. 10 is a left side view of the revolving body 4 of the hydraulic excavator 100 in a modified example. Fig. 11 is a right side view of the revolving body 4 of the hydraulic excavator 100 in a modified example. In this case, water inlet 79a is provided on the front side of the vehicle, and water inlet 86a is provided on the rear side of the vehicle. In this case, the direction toward the front of the vehicle can be said to be the first direction, and the direction toward the rear of the vehicle can be said to be the second direction. In this embodiment, water inlet 79a and water inlet 86a can be said to be arranged along the front-to-rear direction of the vehicle. In this case, the same water is used as the electric device cooling water 90b and the auxiliary device cooling water 90c, and the water supply port 86a is provided as a water supply port for replenishing the water without distinguishing between them.

[0046] 7 and 8 show a state in which the vehicle body cover 210 is attached. Fig. 7 shows the state of the vehicle body cover 210 when cooling water is not being replenished, and Fig. 8 shows the state of the vehicle body cover 210 when cooling water is being replenished. As shown in Figs. 7 and 8, when refilling the fuel cell cooling water 90a, the worker opens the water inlet cover 211 provided on the upper part of the water inlet 79a of the vehicle body cover 210. This allows the worker to open the water inlet 79a and refill the fuel cell cooling water 90a. On the other hand, when refilling the electric device cooling water 90b and the auxiliary cooling water 90c, the worker opens the water inlet cover 212 provided on the upper part of the water inlet 86a of the vehicle body cover 210. This allows the worker to open the water inlet 86a and refill the electric device cooling water 90b and the auxiliary cooling water 90c. In other words, different water inlet covers are opened when refilling the fuel cell cooling water 90a and when refilling the electric device cooling water 90b and the auxiliary cooling water 90c. In this case, it can be said that the water inlet cover 211 that covers the water inlet 79a and the water inlet cover 212 that covers the water inlet 86a are separate members. This allows different water supply port covers to be opened depending on the type of cooling water, making it difficult to replenish the wrong cooling water.

[0047] Although the present embodiment has been described above, the technical scope of the present invention is not limited to the scope described in the above embodiment. It is clear from the claims that various modifications and improvements to the above embodiment are also included in the technical scope of the present invention. [Explanation of symbols]

[0048] 8...operator cab, 10...counterweight, 21...fuel cell, 23...electric motor, 70...cooling system, 70a...fuel cell cooling system, 70b...electric equipment cooling system, 70c...fuel cell auxiliary cooling system, 71a...fuel cell cooling circuit, 71b...electric equipment cooling circuit, 71c...auxiliary equipment cooling circuit, 72...fuel cell radiator, 73a, 73b, 73c...electric fan, 79a, 84a, 85a, 86...water inlet, 82...electric equipment radiator, 83...auxiliary equipment radiator, 100...hydraulic excavator, 210...body cover, 211, 212...water inlet cover

Claims

1. An electric motor as a power source; a fuel cell for generating power to be supplied to the electric motor; a first water supply port for supplying water to a first cooling circuit that circulates a first cooling water for cooling the fuel cell; a second water supply port for supplying water to a second cooling circuit through which a second cooling water for cooling the electric motor is circulated; Equipped with The first water supply port is provided on one side of the machine, The second water supply port is provided on the other side of the machine. A working machine characterized by:

2. the first cooling circuit is provided with a first heat exchanger; the second cooling circuit is provided with a second heat exchanger; The first heat exchanger is provided on the one side of the device itself, The second heat exchanger is provided on the other side of the device and opposite to the first heat exchanger.

2. The work machine of claim 1.

3. a first cooling fan for cooling the first heat exchanger; a second cooling fan that cools the second heat exchanger, 3. The work machine according to claim 2, wherein the first cooling fan and the second cooling fan are disposed opposite each other.

4. 2. The work machine according to claim 1, wherein the first water supply port and the second water supply port are arranged along the left-right direction of the work machine.

5. It has a driver's cab, The work machine according to claim 4 , wherein the first water supply port is provided at a position on the driver's cab side in the left-right direction of the work machine.

6. 2. The work machine according to claim 1, wherein the first water supply port and the second water supply port are arranged along a fore-aft direction of the work machine.

7. 2. The work machine according to claim 1, wherein a water inlet cover covering the first water inlet and a water inlet cover covering the second water inlet are separate members.

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