Working machine

Abstract

To provide a work machine capable of suppressing the amount of battery electric discharge when an operation member is switched to a non-operation state to an operation state to suppress deterioration of a battery.SOLUTION: A hydraulic shove is provided with: a main pump 22 driven by a motor 15; a work operation device 18A that outputs an operational signal corresponding to an operational amount of an operational lever; a boom control valve 26 driven through pilot pressure generated in response to the operational signal of the work operation device 18A to control a flow direction and control flow rate of pressured oil from the main pump 22 to a boom cylinder 8; fuel cells 36; a battery 40; and a vehicle body controller 32. The vehicle controller 32 sets, when the operational lever is not operated, a preset standard power at target power to control power of the fuel cells 36 so as to make it closer to the target power and controls electric charge and discharge of the battery so as to discharge electricity to compensate power shortage of the fuel cell by charging excessive amount of the power of the fuel cells 36.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a working machine such as a hydraulic excavator.

Background Art

[0002] Patent Document 1 discloses a vehicle such as a passenger car, which includes an electric motor that drives wheels, a fuel cell that generates electric power supplied to the electric motor, a battery that charges an excess of the electric power generated by the fuel cell and supplements a shortage of the electric power of the fuel cell, and a controller.

[0003] The controller of Patent Document 1 calculates required power using the accelerator opening degree acquired by an accelerator opening degree sensor and the vehicle speed acquired by a vehicle speed sensor, and sets target power using this required power. Then, the power of the fuel cell is controlled to approach the target power, and the charging and discharging of the battery are controlled to discharge in order to charge an excess of the power of the fuel cell and supplement a shortage of the power of the fuel cell.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when attempting to apply the fuel cell, battery, controller, and its control of Patent Document 1 to a working machine such as a hydraulic excavator, in a working machine such as a hydraulic excavator, compared to a vehicle such as a passenger car, the load required for the electric motor is high, the amount of variation in the load of the electric motor is large, and also, since the switching between the non-operation state and the operation state of the operation member by the driver is frequent, the frequency of variation in the load of the electric motor is high, so it cannot be applied as it is. For example, when the operation lever is switched from the non-operation state to the operation state, the required power that changes according to the operation amount of the operation member rapidly increases, and regardless of whether the operation member is in the operation state or the non-operation state, if the target power is set using the required power that changes according to the operation amount of the operation member, the target power also rapidly increases. Therefore, the power generation power of the fuel cell cannot catch up with the target power, the discharge power of the battery increases, and there is a risk that the battery will deteriorate prematurely.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide a working machine capable of suppressing the discharge power of a battery and suppressing the deterioration of the battery.

Means for Solving the Problems

[0007] To achieve the above object, the present invention includes an electric motor, a hydraulic pump driven by the electric motor, a hydraulic actuator driven by the pressure oil discharged from the hydraulic pump, an operation member operable by a driver, and an operation device that outputs a pilot pressure or an operation signal corresponding to the operation amount of the operation member. A control valve driven by the pilot pressure of the operation device or by a pilot pressure generated corresponding to the operation signal of the operation device, and that controls the flow direction and flow rate of the pressure oil from the hydraulic pump to the hydraulic actuator, a fuel cell that generates electric power supplied to the electric motor, a battery that charges the excess of the electric power generated by the fuel cell and discharges to compensate for the shortage of the electric power of the fuel cell, and uses the required electric power that changes according to the operation amount of the operation member when the operation member is operated to set a target electric power, controls the electric power of the fuel cell so as to approach the target electric power, and controls the charging and discharging of the battery so as to charge the excess of the electric power of the fuel cell and discharge to compensate for the shortage of the electric power of the fuel cell. The vehicle body controller sets a standard electric power, which is preset to be greater than the required electric power corresponding to the non-operation state of the operation member when the operation member is not operated and less than the required electric power corresponding to the maximum operation amount of the operation member, as the target electric power, controls the electric power of the fuel cell so as to approach the target electric power, and controls the charging and discharging of the battery so as to charge the excess of the electric power of the fuel cell and discharge to compensate for the shortage of the electric power of the fuel cell.

Advantages of the Invention

[0008] According to the present invention, it is possible to suppress the discharge power of the battery and suppress the deterioration of the battery.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0010] Taking a hydraulic excavator as an example of the application target of the present invention, an embodiment of the present invention will be described with reference to the drawings.

[0011] FIG. 1 is a side view showing the structure of a hydraulic excavator in the present embodiment. Hereinafter, the front side (the right side in FIG. 1), the rear side (the left side in FIG. 1), the right side (the front side with respect to the plane of the drawing in FIG. 1), and the left side (the back side with respect to the plane of the drawing in FIG. 1) of the driver sitting on the driver's seat in the cab of the hydraulic excavator are simply referred to as the front side, the rear side, the right side, and the left side.

[0012] The hydraulic excavator of the present embodiment includes a travelable traveling body 1, a revolving body 2 rotatably provided above the traveling body 1, and a working device 3 connected to the revolving body 2.

[0013] The traveling body 1 includes, for example, an H-shaped truck frame 4 as viewed from above, a crawler 5 rotatably disposed on the right side portion of the truck frame 4, a right traveling motor 6 for rotating the crawler 5, a crawler (not shown) rotatably disposed on the left side portion of the truck frame 4, and a left traveling motor (not shown) for rotating this crawler. The traveling body 1 travels by the rotation of the right traveling motor 6 and the left traveling motor.

[0014] The working device 3 includes a boom 7 rotatably connected to the revolving body 2, a boom cylinder 8 for rotating the boom 7, an arm 9 rotatably connected to the tip of the boom 7, an arm cylinder 10 for rotating the arm 9, an attachment (such as a bucket 11) rotatably connected to the tip of the arm 9, and an attachment cylinder 12 for rotating the attachment. The working device 3 is driven by the extension and retraction of the boom cylinder 8, the arm cylinder 10, and the attachment cylinder 12. Note that the bucket 11 is for excavating earth and sand, etc., and can be replaced with, for example, a grapple for gripping wood or a breaker for crushing rock formations, etc. Thereby, various operations can be performed.

[0015] The revolving body 2 revolves by the rotation of a slewing motor 13 (see FIG. 2 described later). The revolving body 2 includes a driver's cab 14 where the driver rides, a machine room 16 for housing devices such as an electric motor 15 (see FIG. 2 described later), and a counterweight 17 for maintaining the balance with the working device 3.

[0016] The driver's cab 14 is provided with a driver's seat (not shown) where the driver sits. In front of the driver's seat, a traveling operation device (not shown) for instructing the traveling of the traveling body 1 is provided. On the right side of the driver's seat, a working operation device 18A (see FIG. 2 described later) for instructing the rotation of the boom 7 and the rotation of the attachment, a rotation speed dial 19 (see FIG. 3 described later) for setting the rotation speed of the electric motor 15, etc. are provided. On the left side of the driver's seat, a working operation device 18B (see FIG. 2 described later) for instructing the slewing of the revolving body 2 and the rotation of the arm 9 is provided.

[0017] The hydraulic excavator is provided with a drive device that drives a plurality of hydraulic actuators (specifically, the right travel motor 6, the left travel motor, the boom cylinder 8, the arm cylinder 10, the attachment cylinder 12, and the swing motor 13 described above). FIG. 2 is a diagram showing, as a representative, the configuration related to the drive of the boom cylinder 8 and the swing motor 13 among the configurations of the drive device of the hydraulic excavator in the present embodiment. FIG. 3 is a block diagram showing the functional configuration of the vehicle body controller together with related devices in the present embodiment.

[0018] The drive device of the present embodiment includes the above-described electric motor 15, a power control unit 20 that controls the rotational speed of the electric motor 15, a rotational speed sensor 21 that detects the rotational speed of the electric motor 15, a variable displacement main pump 22 (hydraulic pump) driven by the electric motor 15, a regulator 23 that adjusts the capacity of the main pump 22 (specifically, the tilt angle of the swash plate), a main relief valve 24 that limits the discharge pressure of the main pump 22, a discharge pressure sensor 25 that detects the discharge pressure of the main pump 22, a boom control valve 26 that controls the flow direction and flow rate of the pressure oil from the main pump 22 to the boom cylinder 8, and a swing control valve 27 that controls the flow direction and flow rate of the pressure oil from the main pump 22 to the swing motor 13.

[0019] Further, the drive device of the present embodiment includes a pilot pump 28 driven by the electric motor 15, a pilot relief valve 29 that limits the discharge pressure of the pilot pump 28, boom solenoid valves 30A, 30B that generate a pilot pressure using the discharge pressure of the pilot pump 28 as the source pressure and output the generated pilot pressure to the pressure receiving portion of the boom control valve 26, swing solenoid valves 31A, 31B that generate a pilot pressure using the discharge pressure of the pilot pump 28 as the source pressure and output the generated pilot pressure to the pressure receiving portion of the swing control valve 27, and a vehicle body controller 32.

[0020] The vehicle body controller 32 includes a processor that executes processing according to a program, a memory that stores the program and data, and an interface that can communicate with other controllers described later. Functionally, the vehicle body controller 32 includes a solenoid valve control unit 33, a pump capacity control unit 34, and a motor speed control unit 35.

[0021] The working operation device 18A includes an operation lever (operation member) operable by the driver, a first potentiometer that generates and outputs a first operation signal according to the operation amount on the front side of the operation lever, and a second potentiometer that generates and outputs a second operation signal according to the operation amount on the rear side of the operation lever.

[0022] The working operation device 18B includes an operation lever (operation member) operable by the driver, a third potentiometer that generates and outputs a third operation signal according to the operation amount on the front side of the operation lever, and a fourth potentiometer that generates and outputs a fourth operation signal according to the operation amount on the rear side of the operation lever.

[0023] The solenoid valve control unit 33 of the vehicle body controller 32 generates a drive signal according to the first operation signal from the working operation device 18A and outputs it to the boom solenoid valve 30A. The boom solenoid valve 30A generates a pilot pressure corresponding to the drive signal and outputs it to a pressure receiving part on one side of the boom control valve 26. As a result, the boom control valve 26 is switched to the switching position on the right side in the figure, and the pressure oil from the main pump 22 is supplied to the upper rod chamber of the boom cylinder 8 via the boom control valve 26, and the boom cylinder 8 shortens. As a result, the boom 7 descends.

[0024] The solenoid valve control unit 33 of the vehicle body controller 32 generates a drive signal according to the second operation signal from the work operation device 18A and outputs it to the boom solenoid valve 30B. The boom solenoid valve 30B generates a pilot pressure corresponding to the drive signal and outputs it to the pressure receiving part on the other side of the boom control valve 26. As a result, the boom control valve 26 is switched to the switching position on the left side in the figure, and the pressurized oil from the main pump 22 is supplied to the bottom chamber on the lower side in the figure of the boom cylinder 8 through the boom control valve 26, and the boom cylinder 8 extends. As a result, the boom 7 rises.

[0025] The solenoid valve control unit 33 of the vehicle body controller 32 generates a drive signal according to the third operation signal from the work operation device 18B and outputs it to the swing solenoid valve 31A. The swing solenoid valve 31A generates a pilot pressure corresponding to the drive signal and outputs it to the pressure receiving part on one side of the swing control valve 27. As a result, the swing control valve 27 is switched to the switching position on the right side in the figure, and the pressurized oil from the main pump 22 is supplied to the port on the upper side in the figure of the swing motor 13 through the swing control valve 27, and the swing motor 13 rotates in one direction. As a result, the swing body 2 swings to the right.

[0026] The solenoid valve control unit 33 of the vehicle body controller 32 generates a drive signal according to the fourth operation signal from the work operation device 18B and outputs it to the swing solenoid valve 31B. The swing solenoid valve 31B generates a pilot pressure corresponding to the drive signal and outputs it to the pressure receiving part on the other side of the swing control valve 27. As a result, the swing control valve 27 is switched to the switching position on the left side in the figure, and the pressurized oil from the main pump 22 is supplied to the port on the lower side in the figure of the swing motor 13 through the swing control valve 27, and the swing motor 13 rotates in the opposite direction. As a result, the swing body 2 swings to the left.

[0027] Although not shown in the figure, the configurations related to the drive of the right traveling motor 6, the left traveling motor, the arm cylinder 10, and the attachment cylinder 12 are also substantially the same.

[0028] The pump capacity control unit 34 of the vehicle body controller 32 controls the regulator 23 to adjust the capacity of the main pump 22 based on the maximum value among the operation signals from the traveling operation device and the working operation devices 18A and 18B, the discharge pressure of the main pump 22 detected by the discharge pressure sensor 25, and the rotational speed of the electric motor 15 detected by the rotational speed sensor 21.

[0029] The power control unit 20 includes a DC / AC converter that converts DC power into AC power, an inverter that varies the frequency of the AC power converted by the DC / AC converter, and an inverter controller that controls the inverter. The inverter controller has a processor that executes processing according to a program, a memory that stores the program and data, and an interface capable of communicating with the vehicle body controller 32.

[0030] The electric motor rotational speed control unit 35 of the vehicle body controller 32 transmits the rotational speed of the electric motor 15 set by the rotational speed dial 19 to the inverter controller as the target rotational speed. Also, when the duration of the non-operation state of the traveling operation device and the working operation devices 18A and 18B (in other words, all the operation levers) reaches a predetermined value T, a predetermined idle rotational speed is transmitted to the inverter controller as the target rotational speed. The inverter controller controls the inverter so that the rotational speed of the electric motor 15 detected by the rotational speed sensor 21 becomes the aforementioned target rotational speed.

[0031] The drive device of the present embodiment further includes a fuel cell 36 that generates electric power by chemically reacting hydrogen and oxygen, a boost converter 37 that boosts the electric power generated by the fuel cell 36 and supplies it to the power control unit 20, a fuel cell controller 38 that controls the fuel cell 36 and the boost converter 37, a battery 40 (power storage device) connected to the boost converter 37 and the power control unit 20 via a DC / DC converter 39, and a battery controller 41 that controls the DC / DC converter 39. The battery 40 charges the excess power of the fuel cell 36 and discharges to compensate for the shortage of the power of the fuel cell.

[0032] The fuel cell controller 38 includes a processor that executes processing according to a program, a memory that stores programs and data, and an interface capable of communicating with the vehicle body controller 32. The fuel cell controller 38 monitors the fuel cell 36 based on the state quantities of the fuel cell 36 detected by a plurality of fuel cell sensors (not shown), and transmits the result to the vehicle body controller 32.

[0033] The battery controller 41 includes a processor that executes processing according to a program, a memory that stores programs and data, and an interface capable of communicating with the vehicle body controller 32. The battery controller 41 monitors the battery 40 based on the state quantities of the battery 40 detected by a plurality of battery sensors (not shown), and transmits the result to the vehicle body controller 32.

[0034] The vehicle body controller 32 further includes a power control unit 42 as a functional configuration. The power control unit 42 of the vehicle body controller 32 sets a target power (details will be described later) and transmits it to the fuel cell controller 38. The fuel cell controller 38 controls the fuel cell 36 so that the generated power of the fuel cell 36 approaches the target power, and controls the boost converter 37.

[0035] When the power of the fuel cell 36 is excessive with respect to the target power and the state of charge of the battery 40 is less than a predetermined value (for example, 90%), the power control unit 42 of the vehicle body controller 32 transmits a charging command to the battery controller 41. The battery controller 41 controls the DC / DC converter 39 in response to the charging command, charges the battery 40 using a part of the power of the fuel cell 36, and controls the charging power. Thereby, the excess of the power of the fuel cell 36 is consumed.

[0036] When the power of the fuel cell 36 is excessive with respect to the target power and the state of charge of the battery 40 is equal to or greater than a predetermined value, the power control unit 42 of the vehicle body controller 32 controls the load adjustment device 43 to increase the load on the electric motor 15. The load adjustment device 43 is, for example, a variable throttle valve disposed in the oil passage between the boom control valve 26 and the tank, and it is possible to increase the discharge pressure of the main pump 22 by reducing its opening degree. Thereby, it is possible to increase the load on the electric motor 15.

[0037] When the power of the fuel cell 36 is insufficient with respect to the target power, the power control unit 42 of the vehicle body controller 32 transmits a discharge command to the battery controller 41. The battery controller 41 controls the DC / DC converter 39 in response to the discharge command to discharge the battery 40 and control the discharge power. Thereby, the shortage of the power of the fuel cell 36 is compensated for.

[0038] The most significant feature of this embodiment lies in the method for setting the above-described target power, which will be described with reference to FIG. 4. FIG. 4 is a flowchart showing the procedure for setting the target power of the vehicle body controller in this embodiment.

[0039] In step S1, the power control unit 42 of the vehicle body controller 32 determines whether any of the operation levers of the traveling operation device and the working operation devices 18A and 18B is in an operating state. If any of the operation levers is in an operating state, the process proceeds to step S2, and the required power that changes according to the operation amount of the operation lever is calculated. Specifically, the power consumption of the electric motor 15 is calculated based on the control information of the regulator 23 by the pump capacity control unit 34 of the vehicle body controller 32, and the power consumption of the electric motor 15 is calculated based on the control information of the inverter by the inverter controller. The larger of these is taken as the true value of the power consumption of the electric motor 15. Then, the power consumption of the electric motor 15 and the power of the devices other than the electric motor 15 (including the power required when the state of charge of the battery 40 significantly decreases and the battery 40 needs to be charged) are added together to calculate the required power. Then, leveling processing (specifically, processing using a low-pass filter) is performed on the data of the required power at a predetermined time.

[0040] Thereafter, the process proceeds to step S3, where the leveled required power is compared with a standard power PC (see FIG. 6 described later) that is set in advance to be greater than the required power PA corresponding to the non-operating state of the operation lever and less than the required power PB corresponding to the maximum operation amount of the operation lever, and the larger of them is set as the target power.

[0041] If all the operation levers are in the non-operating state in step S1, the process proceeds to step S4. In step S4, the power control unit 42 of the vehicle body controller 32 determines whether the duration of the non-operating state of all the operation levers is equal to or greater than a predetermined value T. If the duration of the non-operating state of all the operation levers is less than the predetermined value T, the process proceeds to step S5, where the target power is set using the standard power PC. In the present embodiment, when all the operation levers become in the non-operating state, the standard power PC is set as the target power, and thereafter, the target power is decreased as the duration of the non-operating state of all the operation levers increases (see FIG. 6 described later).

[0042] If the duration of the non-operating state of all the operation levers is equal to or greater than the predetermined value T in step S4, the process proceeds to step S6. At this time, the motor speed control unit 35 of the vehicle body controller 32 has decreased the rotation speed of the motor 15 to a predetermined idle rotation speed. Therefore, in step S6, the power control unit 42 of the vehicle body controller 32 sets the minimum required power PD (where PD < PA) corresponding to the non-operating state of the operation lever and the predetermined idle rotation speed as the target power (see FIG. 6 described later).

[0043] Next, the effects of the present embodiment will be described using a comparative example. FIG. 5 is a time chart showing the changes over time in the operation amount of the operation lever, the target power, and the power of the fuel cell in the comparative example. FIG. 6 is a time chart showing the changes over time in the operation amount of the operation lever, the target power, and the power of the fuel cell in the present embodiment.

[0044] Regardless of the operating state and non-operating state of the operation lever, the vehicle body controller of the comparative example sets the required power corresponding to the operation amount of the operation lever as the target power, controls the power of the fuel cell so as to approach the target power, and charges the excess power of the fuel cell and discharges to compensate for the shortage to control the charging and discharging of the battery. That is, when the operation lever is not operated (time t1), the required power PA corresponding to the non-operating state of the operation lever is set as the target power. Then, when the operation lever is switched from the non-operating state to the operating state (time t2), the required power that changes according to the operation amount of the operation lever suddenly increases, and the target power also suddenly increases. Therefore, the power generation power of the fuel cell cannot catch up with the target power, and the discharge power of the battery increases (see the hatched portion in FIG. 5).

[0045] On the other hand, the vehicle body controller 32 of the present embodiment sets the target power using the standard power PC that is set in advance to be larger than the required power PA corresponding to the non-operating state of the operation lever and smaller than the required power PB corresponding to the maximum operation amount of the operation lever when the operation lever is not operated (time t1). Then, when the operation lever is switched from the non-operating state to the operating state (time t2), even if the required power that changes according to the operation amount of the operation lever suddenly increases, since the target power is maintained high, the increase amount of the target power can be suppressed. Therefore, the discharge power of the battery 40 can be suppressed (see the hatched portion in FIG. 6). As a result, the deterioration of the battery 40 can be suppressed.

[0046] Also, the vehicle body controller 32 of the present embodiment decreases the target power in accordance with an increase in the duration of the non-operating state of the operation lever. Further, the vehicle body controller 32 of the present embodiment sets the minimum required power PD corresponding to the non-operating state of the operation lever and a predetermined idle rotation speed as the target power when the duration of the non-operating state of the operation lever reaches a predetermined value T. Therefore, energy saving can be achieved.

[0047] Note that, as in the modification example shown in FIG. 7, the hydraulic excavator may be provided with a mode selection device 44 for selecting one of a plurality of modes (for example, an eco mode, a power mode, and a high power mode). The mode selection device 44 is composed of, for example, a mode selection dial capable of selecting one of a plurality of modes, or a plurality of mode switches each capable of selecting a plurality of modes.

[0048] The vehicle body controller 32 of this modification example controls the rotational speed of the electric motor 15 via the power control unit 20 according to the mode selected by the mode selection device 44, and controls the capacity of the main pump 22 via the regulator 23 to variably step the torque of the main pump 22. For example, in the eco mode, the torque of the main pump 22 is at a low level, in the power mode, the torque of the main pump 22 is at a medium level, and in the high power mode, the torque of the main pump 22 is at a high level.

[0049] Also, the vehicle body controller 32 of this modification example varies the standard power PC in accordance with the change in the torque of the main pump 22 described above. That is, in the eco mode, the standard power PC is at a low level, in the power mode, the standard power PC is at a medium level, and in the high power mode, the standard power PC is at a high level. Even in such a modification example, the same effects as those of the above-described embodiment can be obtained.

[0050] Also, in the above-described embodiment, the vehicle body controller 32 has been described by taking as an example the case where the standard power PC is set to the target power when the operation lever is switched from the operated state to the non-operated state, and then the target power is decreased according to the duration of the non-operated state of the operation lever. However, the present invention is not limited to this. The vehicle body controller 32 may fix the target power to the standard power PC until the duration of the non-operated state of the operation lever reaches a predetermined value.

[0051] In addition, in the above-described embodiment, the vehicle body controller 32 has been described by taking as an example the case where it has an idle function of reducing the rotational speed of the electric motor 15 to a predetermined idle rotational speed when the duration of the non-operation state of the operation lever reaches a predetermined value. However, the present invention is not limited to this. The vehicle body controller 32 may not have an idle function. That is, when the duration of the non-operation state of the operation lever reaches a predetermined value, it may not be necessary to change the target power to the minimum required power PD.

[0052] In addition, in the above-described embodiment, a battery has been described as the secondary battery that charges the excess power of the fuel cell and compensates for the shortage of power of the fuel cell. However, a capacitor having the same function may be applied.

[0053] In the above, a hydraulic excavator has been described as an example of the application target of the present invention. However, the present invention is not limited to this, and the present invention may be applied to other working machines.

Explanation of Reference Numerals

[0054] 6 Travel motor 8 Boom cylinder 10 Arm cylinder 12 Attachment cylinder 13 Swing motor 15 Electric motor 18A, 18B Working operation device 22 Main pump (hydraulic pump) 26 Boom control valve 27 Swing control valve 32 Vehicle body controller 36 Fuel cell 40 Battery

Claims

1. An electric motor, A hydraulic pump driven by the electric motor, A hydraulic actuator driven by the pressure oil discharged from the hydraulic pump, An operating device having an operating member operable by an operator and outputting a pilot pressure or an operation signal corresponding to the operation amount of the operating member, A control valve driven by the pilot pressure of the operating device or by a pilot pressure generated corresponding to the operation signal of the operating device, and controlling the flow direction and flow rate of the pressure oil from the hydraulic pump to the hydraulic actuator, A fuel cell that generates electric power supplied to the electric motor, A battery that charges the excess of the electric power generated by the fuel cell and discharges to compensate for the shortage of the electric power of the fuel cell, A vehicle body controller that sets a target power using a required power that changes according to the operation amount of the operating member when the operating member is operated, controls the power of the fuel cell so as to approach the target power, and controls the charging and discharging of the battery so as to charge the excess of the electric power of the fuel cell and discharge to compensate for the shortage of the electric power of the fuel cell. The vehicle body controller sets a standard power, which is preset to be greater than the required power corresponding to the non-operation state of the operating member when the operating member is not operated and less than the required power corresponding to the maximum operation amount of the operating member, as the target power, controls the power of the fuel cell so as to approach the target power, and controls the charging and discharging of the battery so as to charge the excess of the electric power of the fuel cell and discharge to compensate for the shortage of the electric power of the fuel cell. A working machine characterized by this.

2. In the working machine according to Claim 1, When the operating member is switched from the operating state to the non-operating state, the vehicle body controller sets the standard power as the target power, and then decreases the target power in accordance with an increase in the duration of the non-operation state of the operating member. A working machine characterized by this.

3. In the working machine according to claim 1, when the duration of the non-operation state of the operation member reaches a predetermined value, the vehicle body controller reduces the rotational speed of the electric motor to a predetermined idle rotational speed, sets the minimum required power corresponding to the non-operation state of the operation member and the predetermined idle rotational speed as the target power, controls the power of the fuel cell so as to approach the target power, and controls the charging and discharging of the battery so as to charge the excess of the power of the fuel cell and discharge to compensate for the shortage of the power of the fuel cell. The working machine is characterized by the above.

4. In the working machine according to claim 1, the vehicle body controller sets the larger of the required power and the standard power that changes according to the operation amount of the operation member when the operation member is operated as the target power, controls the power of the fuel cell so as to approach the target power, and controls the charging and discharging of the battery so as to charge the excess of the power of the fuel cell and discharge to compensate for the shortage of the power of the fuel cell. The working machine is characterized by the above.

5. In the working machine according to claim 1, comprising a mode selection device for selecting one of a plurality of modes, the vehicle body controller controls the rotational speed of the electric motor and the capacity of the hydraulic pump according to the mode selected by the mode selection device to vary the torque of the hydraulic pump and varies the standard power. The working machine is characterized by the above.

6. In the working machine according to claim 1, comprising a load adjustment device for adjusting the load of the electric motor, when the power of the fuel cell exceeds the target power and the power storage rate of the battery is equal to or higher than a predetermined value, the vehicle body controller controls the load adjustment device to increase the load of the electric motor. The working machine is characterized by the above.

Images