Work vehicles

Abstract

To provide a work vehicle that can consume regenerative electric power.SOLUTION: A work vehicle comprises an electric motor, a travelling body, and a cooling device. The travelling body is driven by the electric motor. The cooling device is driven by regenerative electric power of the electric motor generated by braking the travelling body to cool an instrument provided in the work vehicle.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to work vehicles. [Background technology]

[0002] In open-cut mines, transport vehicles are sometimes driven downhill continuously for long periods of time. In such cases, it becomes necessary to keep the brakes applied while the vehicle is traveling downhill in order to maintain a constant downhill speed. Patent Document 1 discloses an electrically driven dump truck that converts regenerative power generated by braking into thermal energy using a resistor (retarder grid). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-054117 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to generate braking force by converting regenerative power into heat using a retarder grid, a large retarder grid capable of consuming the large amount of energy generated when going downhill is required. The retarder grid mounted on a large dump truck is installed on a platform. The platform is a flat portion of the vehicle body located above the front wheels. However, when installing structures other than the retarder grid on the platform, it is preferable to reduce the size of the retarder grid. For example, in order to install a hydrogen tank on the platform of a transport vehicle powered by a fuel cell, it is preferable to reduce the proportion of the platform occupied by the retarder grid. In order to reduce the size of the retarder grid, it is necessary to reduce the power consumed by the retarder grid.

[0005] An object of the present disclosure is to provide a work vehicle that is capable of consuming regenerative power. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, a work vehicle includes an electric motor, a running body driven by the electric motor, and a cooling device that is driven by regenerative power of the electric motor generated by braking the running body and that cools equipment provided on the work vehicle. [Effects of the Invention]

[0007] According to the above aspect, the work vehicle can consume regenerated power. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view schematically showing a transporter vehicle according to a first embodiment. [Figure 2] 1 is a diagram showing a configuration of a wet brake according to a first embodiment; [Figure 3] 1 is a schematic block diagram showing a configuration of an electrical system provided in a transporter vehicle according to a first embodiment. [Figure 4] FIG. 2 is a schematic block diagram showing the configuration of a control device according to the first embodiment. [Figure 5] 4 is a flowchart showing retarder control by the control device according to the first embodiment. [Figure 6] FIG. 10 is a schematic diagram showing the configuration of a wet brake according to a second embodiment. [Figure 7] FIG. 10 is a schematic diagram showing the configuration of a wet brake according to a third embodiment. [Figure 8] FIG. 10 is a schematic block diagram showing the configuration of an electrical system provided in a transporter vehicle according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] First Embodiment Configuration of transport vehicle 10 Hereinafter, the embodiments will be described in detail with reference to the drawings. The transport vehicle 10 according to the first embodiment is a rigid frame dump truck that transports crushed stone and the like excavated from a mine or the like. The transport vehicle 10 is powered by a fuel cell 41 that uses hydrogen gas as fuel. The transport vehicle 10 is an example of a work vehicle. 1 is a perspective view schematically showing a transporter vehicle 10 according to the first embodiment. The transporter vehicle 10 includes a dump body 11, a vehicle body 12, and a traveling device 13.

[0010] The dump body 11 is a member on which a load is loaded. At least a portion of the dump body 11 is disposed above the vehicle body 12. The dump body 11 performs a dumping operation and a lowering operation. By the dumping operation and the lowering operation, the dump body 11 is adjusted to a dumping position and a loaded position. The dump position refers to a position in which the dump body 11 is raised. The loaded position refers to a position in which the dump body 11 is lowered.

[0011] The dumping operation refers to an operation of moving the dump body 11 away from the vehicle body 12 and tilting it in the dumping direction. The dumping direction is toward the rear of the vehicle body 12. In the embodiment, the dumping operation includes lifting the front end of the dump body 11 and tilting the dump body 11 rearward. Due to the dumping operation, the loading surface of the dump body 11 tilts downward toward the rear.

[0012] The lowering operation refers to an operation of bringing the dump body 11 closer to the vehicle body 12. In the embodiment, the lowering operation includes lowering the front end of the dump body 11.

[0013] When performing soil removal work, the dump body 11 performs a dumping operation to change from a loaded position to a dumping position. If a load is loaded on the dump body 11, the load is discharged rearward from the rear end of the dump body 11 by the dumping operation. When a loading operation is performed, the dump body 11 is adjusted to the loaded position.

[0014] The vehicle body 12 includes a body frame (not shown). The vehicle body 12 rotatably supports the dump body 11 via hinge pins provided on the body frame. The vehicle body 12 is supported by the traveling gear 13. A platform 121 is provided on the body frame above the front wheels of the traveling gear 13. The platform 121 is a flat plate that forms the upper surface of the vehicle body frame. A driver's cab 122, a control cabinet 123, and a retarder grid 48 are provided on the platform 121. A fuel cell 41 is also provided on the body frame. An opening is provided in the front of the vehicle body 12 in front of the fuel cell 41, and a grill 124 is provided in the opening. A fan 125 for cooling the fuel cell 41 is provided between the grill 124 and the fuel cell 41. The fan 125 cools the fuel cell 41 by drawing outside air into the body frame through the grill 124. The fan 125 is an example of a cooling device for the fuel cell 41.

[0015] The control cabinet 123 converts power. Specifically, the control cabinet 123 controls power between the fuel cell 41, various electrical devices (the battery 42, the traction motor 47, the pump motor 43, etc.), and the retarder grid 48. The retarder grid 48 is a resistor for absorbing regenerative power generated by braking the traveling device 13. The retarder grid 48 converts the regenerative power into thermal energy.

[0016] The traveling device 13 supports the vehicle body 12. The traveling device 13 causes the transport vehicle 10 to travel. The traveling device 13 causes the transport vehicle 10 to move forward or backward. At least a portion of the traveling device 13 is disposed below the vehicle body 12. The traveling device 13 has a pair of front wheels and a pair of rear wheels. The front wheels are steered wheels, and the rear wheels are drive wheels. At least the drive wheels of the traveling device 13 are provided with wet brakes 14.

[0017] 《Configuration of Wet Brake 14》 FIG. 2 is a diagram showing the configuration of the wet brake 14 according to the first embodiment. The wet brake 14 brakes the rotation of the rotor R of the traveling device 13. The wet brake 14 includes a brake housing 141, a brake cylinder 142, a fixed friction plate 143, a rotating friction plate 144, a cooling oil tank 145, a cooling oil pump 146, and an oil cooler 147. The brake housing 141 is provided so as to cover the rotor R around the axis. The rotor R penetrates the brake housing 141. The inside of the brake housing 141 is filled with cooling oil, and an oil seal is provided at the interface with the rotor R. The fixed friction plates 143 are provided inside the brake housing 141. The brake housing 141 restricts the rotation of the fixed friction plates 143 around the axis of the rotor R and holds them movably in the axial direction of the rotor R. The rotating friction plates 144 are fixed to the rotor R and rotate integrally with the rotor R. Each rotating friction plate 144 is provided so as to be located between two of the fixed friction plates 143. The brake cylinder 142 is supported by the brake housing 141 and presses the fixed friction plates 143 in the axial direction of the rotor R. As a result, the fixed friction plates 143 and the rotating friction plates 144 come into strong contact with each other, generating a frictional force that brakes the rotation of the rotor R. In other words, the wet brake 14 according to the first embodiment is a disc brake.

[0018] A first flow path P1 and a second flow path P2 through which cooling oil flows are provided between the cooling oil tank 145 and the brake housing 141. A cooling oil pump 146 that pumps the cooling oil in the cooling oil tank 145 to the brake housing 141 and an oil cooler 147 that cools the cooling oil are provided in the first flow path P1. The oil cooler 147 cools the cooling oil through heat exchange between the air and the cooling oil. The cooling oil is supplied from the cooling oil tank 145 to the brake housing 141 through the first flow path P1 and returned to the cooling oil tank 145 through the second flow path P2. The cooling oil supplied to the brake housing 141 recovers heat generated by friction between the fixed friction plates 143 and the rotating friction plates 144. In other words, the cooling oil tank 145, the cooling oil pump 146, and the oil cooler 147 constitute a cooling device for the wet brake 14.

[0019] Note that the wet brake 14 according to another embodiment may be a fluid retarder instead of a disc brake. The fluid retarder includes a brake housing 141 and a propeller fixed to the rotor R inside the brake housing 141. The fluid retarder brakes the rotation of the rotor R by the frictional force generated between the propeller and the fluid when the propeller agitates the fluid inside the brake housing 141. In this case as well, the temperature of the fluid inside the brake housing 141 rises due to frictional heat, so it is necessary to cool the fluid by the cooling oil pump 146 and the oil cooler 147, as in the first embodiment.

[0020] Configuration of Electrical System 40 3 is a schematic block diagram showing the configuration of an electrical system 40 provided in the transporter vehicle 10 according to the first embodiment. The electrical system 40 includes a fuel cell 41, a battery 42, a pump motor 43, a first fan motor 44, a second fan motor 45, an air conditioner 46, a traction motor 47, a retarder grid 48, a first DCDC converter 49, a second DCDC converter 50, a first inverter 51, a third DCDC converter 54, a second inverter 55, and a control device 60. The first DCDC converter 49, the second DCDC converter 50, the first inverter 51, the third DCDC converter 54, the second inverter 55, and the control device 60 are provided in a control cabinet 123.

[0021] The fuel cell 41 generates electric power by reacting hydrogen gas supplied from a hydrogen tank (not shown) with oxygen contained in the outside air. The first DC-DC converter 49 supplies the DC power generated by the fuel cell 41 to the bus B. The battery 42 stores the power generated in the fuel cell 41. The battery 42 stores the regenerated power generated in the traction motor 47. The battery 42 outputs the stored power. The second DCDC converter 50 supplies the power charged in the battery 42 to the bus B. The second DCDC converter 50 also charges the battery 42 by adjusting the voltage of the DC power flowing through the bus B and supplying it to the battery 42. In other words, the second DCDC converter 50 is an example of a charging device. The battery 42 is equipped with a BMS (Battery Management System) (not shown) that monitors the state of the battery 42. The BMS measures the charging rate of the battery 42 and outputs the measurement data to the control device 60.

[0022] The pump motor 43 drives a cooling oil pump 146 shown in Fig. 2 using DC power flowing through the bus B. The pump motor 43 according to the first embodiment drives at a rotation speed according to the required load regardless of the presence or absence of regenerative power. In other words, the cooling oil pump 146 drives regardless of the presence or absence of regenerative power. The first fan motor 44 drives the fan 125 shown in FIG. The second fan motor 45 drives a fan 421 provided near the battery 42 for cooling the battery 42 by DC power flowing through the bus B. The fan 421 is an example of a cooling device for the battery 42.

[0023] The air conditioner 46 adjusts the temperature inside the cab 122. Specifically, the air conditioner 46 includes a compressor, a condenser, an expansion valve, and an evaporator. The compressor is driven by electricity and compresses the refrigerant. The condenser dissipates heat from the refrigerant by heat exchange between the high-pressure refrigerant discharged from the compressor and cooling water. The expansion valve reduces the pressure of the refrigerant that has passed through the condenser. The evaporator evaporates the refrigerant by heat exchange between the low-pressure refrigerant flowing from the expansion valve and the air inside the cab 122. As a result, cooled air is supplied to the cab 122. The air conditioner 46 is an example of a cooling device for the cab 122.

[0024] The traction motor 47 is a three-phase AC electric motor that drives the traction device 13. The inverter 51 converts the DC power flowing through the bus B into three-phase AC power and supplies it to the traction motor 47. The inverter 51 also converts regenerative power generated in the traction motor 47 by braking the traction device 13 into DC power and supplies it to the bus B. The traction motor 47 is provided with a voltmeter 52. The voltmeter 52 measures the voltage related to the traction motor 47. The voltmeter 52 transmits the measurement data to the control device 60.

[0025] The control device 60 controls the first DCDC converter 49, the second DCDC converter 50, the inverter 51, the first fan motor 44, the second fan motor 45 and the air conditioner 46 based on measurement data received from the BMS of the battery 42, the voltmeter 52 and the ammeters and voltmeters of other electrical equipment.

[0026] Configuration of the control device 60 FIG. 4 is a schematic block diagram showing the configuration of the control device 60 according to the first embodiment. The control device 60 is a computer including a processor 61 , a main memory 62 , a storage 63 , and an interface 64 . The processor 61 reads a program from the storage 63, loads it into the main memory 62, and executes processing in accordance with the program. Examples of the processor 61 include a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), and a microprocessor.

[0027] The program may be for realizing some of the functions to be performed by the control device 60. For example, the program may be combined with other programs already stored in storage or other programs implemented in other devices to perform the functions. In other embodiments, the control device 60 may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions realized by the processor 61 may be realized by the integrated circuit. Such an integrated circuit is also included as an example of a processor.

[0028] Examples of storage 63 include a magnetic disk, a magneto-optical disk, an optical disk, and a semiconductor memory. Storage 63 may be an internal medium directly connected to the bus, or an external medium connected to control device 60 via interface 64 or a communication line. In addition, when this program is distributed to control device 60 via a communication line, control device 60 that receives the program may load the program into main memory 62 and execute the above-mentioned processing. In at least one embodiment, storage 63 is a non-transitory tangible storage medium.

[0029] The program may also be a program for realizing part of the above-described functions. Furthermore, the program may be a so-called differential file (differential program) that realizes the above-described functions in combination with another program already stored in storage 63.

[0030] <Retarder control by a control device> The transport vehicle 10 according to the first embodiment starts retarder control, for example, when the operator depresses the brake pedal. When retarder control is started, the control device 60 of the transport vehicle 10 causes the travel motor 47 to function as a generator with a load corresponding to the depression of the brake pedal, and generates braking force by consuming the regenerated power in the retarder grid 48 (electric braking). The control device 60 of the transport vehicle 10 excites the brake cylinder 142 to cause the wet brake 14 to generate braking force that is insufficient with the braking force provided by the retarder grid 48 (mechanical braking). Note that the electric brake and the mechanical brake may be simultaneously generated based on the operator depressing the brake pedal.

[0031] 5 is a flowchart showing retarder control by the control device 60 according to the first embodiment. The control device 60 executes the retarder control shown in FIG. 5 at regular intervals. First, the control device 60 determines whether or not regenerative power is being generated based on the depression of the brake pedal (step S1). The control device 60 determines whether or not regenerative power is being generated based on, for example, the measurement value of a potentiometer provided on the brake pedal. Note that the control device 60 according to other embodiments may determine whether or not regenerative power is being generated based on the measurement data (sign of the voltage value) received from the voltmeter 52. If regenerative power is not being generated (step S1: NO), the control device 60 ends the retarder control.

[0032] On the other hand, if regenerative power is being generated (step S1: YES), the control device 60 determines whether the charging rate of the battery 42 is equal to or higher than the upper limit based on the measurement data received from the BMS of the battery 42 (step S2). If the charging rate of the battery 42 is lower than the upper limit (step S2: NO), the control device 60 outputs a charge instruction for the battery 42 to the second DC-DC converter 50 (step S3). This enables the control device 60 to have the regenerative power absorbed by the battery 42 (regenerative braking) and reduce the power consumed by the retarder grid 48 (dynamic braking).

[0033] If the instruction to charge the battery 42 has been output, or if the charging rate of the battery 42 is equal to or higher than the upper limit (step S2: YES), the control device 60 outputs an instruction to drive the cooling device (step S4). That is, the control device 60 outputs drive instructions to the first fan motor 44, the second fan motor 45, and the air conditioner 46. As a result, the first fan motor 44 is driven by the regenerative power flowing through the bus B, and drives the fan 125. Also, the second fan motor 45 is driven by the regenerative power flowing through the bus B, and drives the fan 421. Also, the air conditioner 46 operates by the regenerative power flowing through the bus B. Then, the control device 60 ends the retarder control.

[0034] Actions and Effects In this way, the control device 60 of the transporter vehicle 10 according to the first embodiment operates the first fan motor 44, the second fan motor 45, and the air conditioning device 46, i.e., the cooling device, using the regenerative power of the travel motor 47 generated by braking the travel device 13. This allows the transporter vehicle 10 to have the cooling device absorb the regenerative power. Furthermore, since the temperature of the electrical system 40 rises due to operation of the fuel cell 41, the cooling device can prevent this temperature rise.

[0035] As described above, the transport vehicle 10 according to the first embodiment can reduce the regenerative power consumed by the retarder grid 48 by operating the cooling device. When the travel route of the transport vehicle 10 is known in advance, the size of the retarder grid 48 can be designed based on the braking force of the wet brakes 14 and the amount of power that can be absorbed by the battery 42 and the cooling device. This allows the retarder grid 48 to be made smaller, thereby ensuring space for installing other structures on the platform 121. An example of other structures that can be installed on the platform 121 is a hydrogen tank filled with hydrogen gas to be supplied to the fuel cell 41.

[0036] The first fan motor 44, the second fan motor 45, and the air conditioner 46 may be operating even when no regenerative power is being generated. In this case, the control device 60 controls the cooling device so that the power consumption of the cooling device when regenerative power is being generated is greater than the power consumption of the cooling device when no regenerative power is being generated. For example, when no regenerative power is being generated, the control device 60 may rotate the first fan motor 44 at a rotation speed corresponding to the temperature of the fuel cell 41, or may rotate the first fan motor 44 at a constant rotation speed when no regenerative power is being generated. However, the control device 60 controls the first fan motor 44 so that the rotation speed of the first fan motor 44 when regenerative power is being generated is higher than the rotation speed of the first fan motor 44 when no regenerative power is being generated. Similarly, when no regenerative power is being generated, the control device 60 may rotate the second fan motor 45 at a rotation speed corresponding to the temperature of the battery 42, or may rotate the second fan motor 45 at a constant rotation speed when no regenerative power is being generated. However, the control device 60 controls the second fan motor 45 so that the rotation speed of the second fan motor 45 when regenerative power is being generated is higher than the rotation speed of the second fan motor 45 when no regenerative power is being generated. Furthermore, when regenerative power is not being generated, the control device 60 may operate the air conditioner 46 to maintain the temperature of the cab 122 at a preset temperature. In this case, the control device 60 may lower the set temperature of the air conditioner 46 when regenerative power is being generated, or may control the compressor not to stop regardless of the set temperature.

[0037] The first fan motor 44, the second fan motor 45 and the air conditioner 46 may not operate when no regenerative power is being generated.

[0038] Second Embodiment The wet brakes 14 are cooled by the cooling oil, thereby preventing a decrease in braking force due to heat generation (for example, the occurrence of fade). However, if the transport vehicle 10 is driven downhill for a long period of time, the wet brakes 14 may not be able to cool down fast enough, resulting in a decrease in braking force. In contrast, the transport vehicle 10 according to the second embodiment uses regenerative power to prevent a decrease in the performance of the wet brakes 14.

[0039] 6 is a schematic diagram showing the configuration of a wet brake 14 according to a second embodiment. The wet brake 14 according to the second embodiment includes a refrigerator 148 in the first flow path P1 in addition to the configuration of the first embodiment.

[0040] The refrigerator 148 includes a compressor 1481, a condenser 1482, an expansion valve 1483, and an evaporator 1484. The compressor 1481 is driven by DC power flowing through a bus B and compresses the refrigerant. The condenser 1482 dissipates heat from the refrigerant by heat exchange between the high-pressure refrigerant discharged from the compressor 1481 and cooling water. The expansion valve 1483 reduces the pressure of the refrigerant that has passed through the condenser 1482. The evaporator 1484 evaporates the refrigerant by heat exchange between the low-pressure refrigerant flowing from the expansion valve 1483 and the cooling oil passing through the first flow path P1. This allows the cooling oil passing through the first flow path P1 to dissipate heat. The refrigerator 148 is an example of a cooling device for the wet brake 14.

[0041] When regenerative power is being generated in the travel motor 47, the control device 60 outputs a drive command to the compressor 1481 in addition to the first fan motor 44, the second fan motor 45, and the air conditioner 46 (step S4 in FIG. 5). As a result, the compressor 1481 is driven by the regenerative power flowing through the bus B, and drives the refrigerator 148. This cools the cooling oil supplied to the brake housing 141, making it possible to prevent a decrease in the braking force of the wet brake 14.

[0042] As described above, according to the transport vehicle 10 of the second embodiment, the regenerative power is used to operate the refrigerator 148 of the wet brake 14, thereby absorbing the regenerative power and preventing a decrease in the braking force of the wet brake 14. By preventing a decrease in the braking force of the wet brake 14, the amount of regenerative power generated by the travel motor 47 can be reduced. In other words, the transport vehicle 10 of the second embodiment can significantly reduce the regenerative power absorbed by the retarder grid 48.

[0043] The pump motor 43 according to the second embodiment operates regardless of whether regenerative power is present, while the refrigerator 148 operates only when regenerative power is present. In other words, the combination of the pump motor 43 and the oil cooler 147 is a main cooling device, and the refrigerator 148 is an auxiliary cooling device. This makes it possible to reduce power consumption by the refrigerator 148 when the haulage vehicle 10 is not braking. Furthermore, when the haulage vehicle 10 is braking, the operation of the refrigerator 148 improves the braking force of the wet brake 14 and also makes it possible to absorb regenerative power.

[0044] Third Embodiment The transporter vehicle 10 according to the third embodiment has a different configuration from that of the second embodiment, and improves the braking force of the wet brake 14 during braking. Figure 7 is a schematic diagram showing the configuration of the wet brake 14 according to the third embodiment.

[0045] The wet brake 14 according to the third embodiment includes a third flow path P3 that connects a portion of the first flow path P1 between the cooling oil pump 146 and the oil cooler 147 and a cooling oil tank 145. An auxiliary pump 149 and a check valve V2 are provided in the third flow path P3. The auxiliary pump 149 is driven when the transporter vehicle 10 is braked, and pumps out the cooling oil held in the cooling oil tank 145. The check valve V2 allows the flow of cooling oil from the auxiliary pump 149 toward the oil cooler 147 and blocks the flow of cooling oil from the oil cooler 147 toward the auxiliary pump 149.

[0046] A check valve V1 is provided in the first flow path P1 between the connecting portion with the third flow path P3 and the cooling oil pump 146. The check valve V1 allows the flow of cooling oil from the cooling oil pump 146 toward the oil cooler 147 and blocks the flow of cooling oil from the oil cooler 147 toward the cooling oil pump 146.

[0047] 8 is a schematic block diagram showing the configuration of an electrical system 40 provided in a haulage vehicle 10 according to the third embodiment. In addition to the configuration of the first embodiment, the electrical system 40 according to the third embodiment further includes a fourth DC-DC converter 56, a third inverter 57, and an auxiliary motor 53. The auxiliary motor 53 drives an auxiliary pump 149.

[0048] When regenerative power is being generated in the travel motor 47, the control device 60 outputs a drive command to the auxiliary motor 53 in addition to the first fan motor 44, the second fan motor 45, and the air conditioning device 46 (step S4 in FIG. 5). As a result, the auxiliary motor 53 is driven by the regenerative power flowing through the bus B, which drives the auxiliary pump 149. By increasing the flow rate of cooling oil supplied to the brake housing 141 by the auxiliary pump 149, the cooling performance of the wet brake 14 is improved. As a result, the auxiliary pump 149 can prevent a decrease in the braking force of the wet brake 14.

[0049] The pump motor 43 according to the third embodiment operates regardless of whether regenerative power is present, while the auxiliary motor 53 operates only when regenerative power is present. In other words, the combination of the pump motor 43 and the oil cooler 147 forms a main cooling device, and the combination of the auxiliary motor 53 and the oil cooler 147 forms an auxiliary cooling device. This makes it possible to reduce power consumption by the refrigerator 148 when the haulage vehicle 10 is not braking. Furthermore, when the haulage vehicle 10 is braking, the operation of the auxiliary pump 149 improves the braking force of the wet brake 14 and further absorbs regenerative power.

[0050] Other Embodiments Although one embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design modifications are possible. That is, in other embodiments, the order of the above-described processes may be changed as appropriate. Furthermore, some processes may be executed in parallel. The control device 60 according to the above-described embodiment may be configured by a single computer, or the configuration of the control device 60 may be divided among multiple computers, and the multiple computers may work together to function as the control device 60.

[0051] In the above-described embodiment, the fuel cell 41 and the battery 42 are cooled by fans, but this is not limited to this. For example, a transport vehicle 10 according to another embodiment may be provided with a refrigerator as a cooling device for the fuel cell 41 or the battery 42. In this case, the transport vehicle 10 may constantly rotate the fan 125 and the fan 421 using the first fan motor 44 and the second fan motor 45, and operate the refrigerator when regenerative power is generated. In other words, the transport vehicle 10 may be provided with a refrigerator as an auxiliary cooling device. This allows the fuel cell 41 and the battery 42 to be cooled by blowing air at room temperature when regenerative power is not being generated, and to be cooled by blowing air cooled by the refrigerator when regenerative power is being generated.

[0052] In the above-described embodiment, the fuel cell 41 and the battery 42 are air-cooled by a fan, but this is not limited thereto. For example, the transport vehicle 10 according to another embodiment may be water-cooled, including a circulation pump, a circulation flow path, and a radiator as a cooling device for the fuel cell 41 or the battery 42. In this case, the fuel cell 41 is provided with a circulation flow path for circulating cooling water. The circulation flow path is provided with a circulation pump for supplying cooling water and a radiator for dissipating heat from the cooling water. The radiator cools the cooling water in the radiator by blowing air from the fan 125 or the fan 421 rotated by the first fan motor 44 or the second fan motor 45. As the cooling water supplied by the circulation pump circulates through the circulation flow path, it absorbs heat generated by the power generation reaction in the fuel cell and dissipates the heat in the radiator, thereby cooling the fuel cell.

[0053] In this case, the vehicle 10 may rotate the first fan motor 44 at a rotation speed corresponding to the temperature of the fuel cell 41 when no regenerative power is being generated, or may rotate the first fan motor 44 at a constant rotation speed when no regenerative power is being generated. However, the control device 60 controls the first fan motor 44 so that the rotation speed of the first fan motor 44 when regenerative power is being generated is higher than the rotation speed of the first fan motor 44 when no regenerative power is being generated. Similarly, when no regenerative power is being generated, the control device 60 may rotate the second fan motor 45 at a rotation speed corresponding to the temperature of the battery 42, or may rotate the second fan motor 45 at a constant rotation speed when no regenerative power is being generated. However, the control device 60 controls the second fan motor 45 so that the rotation speed of the second fan motor 45 when regenerative power is being generated is higher than the rotation speed of the second fan motor 45 when no regenerative power is being generated.

[0054] In the above-described embodiment, the transport vehicle 10 is driven by the power generated by the fuel cell 41 and the power stored in the battery 42, but this is not limited to this. For example, the transport vehicle 10 according to another embodiment may not include the fuel cell 41. For example, the transport vehicle 10 according to another embodiment may include only the battery 42 as a drive source and be driven only by the power stored in the battery 42.

[0055] In the above-described embodiment, the transport vehicle 10 has been described as an example of a work vehicle, but this is not limiting. For example, a work vehicle according to other embodiments may be another work vehicle such as a hydraulic excavator, a wheel loader, or a motor grader. [Explanation of symbols]

[0056] 10...Transport vehicle 11...Dump body 12...Vehicle body 121...Platform 122...Driver's cab 123...Control cabinet 124...Grille 125...Fan 13...Traveling gear 14...Wet brake 141...Brake housing 142...Brake cylinder 143...Fixed friction plate 144...Rotating friction plate 145...Cooling oil tank 146...Cooling oil pump 147...Oil cooler 148...Refrigeration unit 1481...Compressor 1482...Condenser 1483...Expansion valve 1484...Evaporator 149...Auxiliary pump 40...Electrical system 41...Fuel cell 42...Battery 421...Fan 43...Pump motor 44...First fan motor 45...Second fan motor 46...Air conditioning unit 47...Travel motor 48...Retarder grid 49...First DCDC converter 50...Second DCDC converter 51...First inverter 52...Voltmeter 53...Auxiliary motor 54...Third DC-DC converter 55...Second inverter 56...Fourth DC-DC converter 57...Third inverter 60...Control device 61...Processor 62...Main memory 63...Storage 64...Interface B...Busbar P1...First flow path P2...Second flow path P3...Third flow path R...Rotor V1...Check valve V2...Check valve

Claims

1. A work vehicle, an electric motor; a running body driven by the electric motor; a cooling device that is driven by regenerative power of the electric motor generated by braking of the traveling body and cools equipment provided in the work vehicle; Equipped with The cooling device is a main cooling device that operates regardless of the regenerative power; an auxiliary cooling device that is driven by the regenerative electric power when the regenerative electric power is generated; A work vehicle equipped with:

2. A fuel cell is provided which generates electricity by reacting hydrogen gas with oxygen in the atmosphere, the electric motor is driven by the power generated by the fuel cell; The cooling device is driven by the regenerative power and cools the fuel cell. The work vehicle according to claim 1 .

3. a brake device that brakes the traveling body by frictional force; The cooling device supplies a refrigerant for cooling the brake device to the brake device. The work vehicle according to claim 1 or 2.

4. The main cooling device has a refrigerant pump that operates regardless of the regenerative power and pressurizes the refrigerant, The auxiliary cooling device has a refrigerator that is driven by the regenerated electric power when the regenerated electric power is generated and cools the refrigerant. The work vehicle according to claim 3 .

5. The main cooling device has a refrigerant pump that operates regardless of the regenerative power and pressurizes the refrigerant, The auxiliary cooling device has an auxiliary pump that is driven by the regenerated power when the regenerated power is generated and that pumps the refrigerant. The work vehicle according to claim 3 or 4, comprising:

6. The power consumption of the cooling device when the regenerative power is generated is greater than the power consumption of the cooling device when the regenerative power is not generated. The work vehicle according to any one of claims 1 to 5.

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