JP2012127478A - Drive device of hydraulic actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive device of a hydraulic actuator that can take out kinetic energy transmitted to the hydraulic actuator as usable energy in a hydraulic circuit of a closed circuit.SOLUTION: A winch 15 is rotated by the weight of a suspended load which descends when performing a reel-down operation, a working fluid of a drive circuit 25 is made to communicate by a hydraulic motor 21 which is driven by the rotating winch 15, and power is generated by the pressure of the working fluid which communicates in the drive circuit 25. By this arrangement, a rotation force which is generated by the transmission of the weight of the descending suspended load to the winch 15 can be utilized as electric energy, and energy efficiency can be improved.

Description

  The present invention relates to a drive device for a hydraulic actuator provided with a hydraulic circuit in which a hydraulic pump and a hydraulic actuator are connected in a closed circuit.

  Conventionally, in this type of hydraulic actuator driving device, a hydraulic actuator driving device in which a hydraulic pump driven by an engine and a hydraulic actuator driven by hydraulic oil discharged from the hydraulic pump are connected in a closed circuit is known. (For example, refer to cited document 1).

JP 2010-203527 A

This hydraulic actuator drive device does not need to control the drive speed of the hydraulic actuator by changing the opening of the valve, unlike the open circuit drive device, but with a variable displacement hydraulic pump used as a hydraulic pump. It is possible. For this reason, this closed circuit drive device can reduce energy loss during operation as compared to an open circuit drive device.
When this drive device is applied to, for example, a winch of a crane, when an operation for lowering the load suspended on the hook is performed, a rotational force generated by transmitting the weight of the lowered load to the winch is applied to the hydraulic motor. . This rotational force is generated at a high frequency when the hydraulic motor is driven, but is not extracted as usable energy, and the efficiency is not sufficiently improved.

  An object of the present invention is to provide a drive device for a hydraulic actuator that can extract energy transmitted to the hydraulic actuator as usable energy in a closed circuit hydraulic circuit.

  The invention according to claim 1 of the present invention includes a hydraulic circuit configured by connecting a hydraulic pump and a hydraulic actuator in a closed circuit, drives the hydraulic pump by engine power, and is discharged from the hydraulic pump. In a hydraulic actuator driving apparatus that drives a hydraulic actuator with oil, hydraulic oil in a hydraulic circuit is circulated by a hydraulic actuator driven by an external force applied from a connected member, and power is generated by the pressure of the hydraulic oil flowing through the hydraulic circuit It is characterized by having a power generation means.

The invention according to claim 2 of the present invention is characterized in that the power generation means is a generator capable of generating power using a hydraulic pump driven as a hydraulic motor by hydraulic oil that circulates in the hydraulic circuit. Power switching means for switching whether to transmit power or to transmit power of a hydraulic pump driven by hydraulic oil to a generator is provided.
According to a third aspect of the present invention, the power generation means includes a hydraulic motor connected to the hydraulic circuit in parallel with the hydraulic pump, a generator capable of generating power using the hydraulic motor as power, and a hydraulic fluid flow of the hydraulic circuit. And a flow path switching means for switching the path to the hydraulic pump side or the hydraulic motor side.
According to a fourth aspect of the present invention, there is provided a battery capable of storing the electric power generated by the generator.
According to a fifth aspect of the present invention, there is provided a storage amount detection unit that detects a storage amount of the battery, and a storage amount detected by the storage amount detection unit in a state where the hydraulic actuator is driven by an external force. A power storage control means for generating power by a generator when the amount is less than a predetermined power storage amount, and for driving the hydraulic pump with engine power without generating power by the generator when the power storage amount is not less than a predetermined power storage amount; It is characterized by having.
According to a sixth aspect of the present invention, in a state where the hydraulic actuator is driven by receiving an external force, if the external force received by the actuator is greater than or equal to a predetermined value, power is generated by a generator, and the external force is less than a predetermined value. In such a case, an operation switching control means for driving the hydraulic pump with the power of the engine without generating power by the generator is provided.

  According to the first aspect of the present invention, since kinetic energy generated in an actuator driven by an external force applied from a connected member can be used as electric energy, energy efficiency can be improved. It becomes possible.

According to the invention described in claim 2 of the present invention, it is possible to convert kinetic energy transmitted to the actuator by a single hydraulic pump into electric energy, so that the manufacturing cost can be reduced by reducing the number of parts. Become.
According to the invention described in claim 3 of the present invention, for the hydraulic pump, switching between a power source when driven as a hydraulic pump and a generator to which an output when driven as a hydraulic motor is transmitted. Since the kinetic energy transmitted to the actuator can be converted into electric energy without requiring a complicated mechanism to be used, the manufacturing cost can be reduced.
According to the invention described in claim 4 of the present invention, the electrical energy converted from the kinetic energy is stored in the battery, so that the energy can be used for other time zones and uses, so that the energy is effectively used. It can be used.
According to the invention described in claim 5 of the present invention, since the battery can be prevented from being overcharged, it is possible to reduce the occurrence of battery failure and extend the life of the battery. It becomes possible.
According to the invention described in claim 6 of the present invention, when the external force received by the actuator is small, the hydraulic pump is driven by the power of the engine. Can be prevented.

It is a side view of the mobile crane which shows one Embodiment of this invention. It is a schematic block diagram of the drive device of a hydraulic actuator. It is a block diagram which shows a control system. It is a schematic block diagram of the drive device of the hydraulic actuator which shows the flow path of the hydraulic fluid at the time of the winding operation | movement by a 1st hydraulic pump. It is a schematic block diagram of the drive device of the hydraulic actuator which shows the flow path of the hydraulic fluid at the time of the winding operation | movement by a 2nd hydraulic pump. It is a schematic block diagram of the drive device of the hydraulic actuator which shows the flow path of the hydraulic fluid at the time of regeneration of the kinetic energy by the 2nd hydraulic pump at the time of lowering operation. It is a flowchart which shows winding-up control processing. It is a flowchart which shows a winding-down control process. It is a schematic block diagram of the drive device of the hydraulic actuator which shows other embodiment of this invention. It is a block diagram which shows a control system.

  1 to 8 show an embodiment of the present invention. In the present embodiment, a case where the hydraulic actuator driving device of the present invention is applied to a mobile crane will be described.

  As shown in FIG. 1, the mobile crane 10 includes a vehicle 11 for traveling, a swivel 12 provided on the vehicle 11 so as to be able to turn, and a telescopic boom provided on the swivel 12 so as to be raised and lowered. 13 and a cabin 14 provided on the side of the telescopic boom 13 on the swivel base 12 for performing operations relating to traveling of the vehicle 11 and operation of the crane.

  A winch 15 is provided at the rear portion of the swivel base 12, and a wire rope 16 wound around the winch 15 is fed out through the distal end portion of the telescopic boom 13. A hook 17 is provided at the tip of the wire rope 16, and a load is suspended from the hook 17.

  The mobile crane 10 includes a winch drive device 20 for winding and unwinding the winch 15 and a controller 30 for controlling the operation of the winch drive device 20.

  The winch drive device 20 is provided in the vehicle 11, a hydraulic motor 21 as a hydraulic actuator that drives the winch 15 to rotate forward and reverse, a first hydraulic pump 22 as a hydraulic pump that is driven by an engine 11 a that runs the vehicle 11, and the vehicle 11. The electric motor 23 as an electric motor driven by the electric power of the battery 11b, the second hydraulic pump 24 as a hydraulic motor driven by the electric motor 23, the hydraulic motor 21, the first hydraulic pump 22, and the second hydraulic pump 24 are closed circuit. A drive circuit 25 as a connected hydraulic circuit, and a hydraulic oil supplement circuit 26 for supplementing the hydraulic fluid to the drive circuit 25 are provided.

  The hydraulic motor 21 can change the rotation direction in accordance with the flow direction of the hydraulic oil flowing through the drive circuit 25. The hydraulic motor 21 has a brake 21a for fixing the rotating shaft except when the winch 15 is driven. Furthermore, the hydraulic motor 21 can be driven by the winch 15 that rotates with the weight of the load that descends, and also has a function as a hydraulic pump that distributes the hydraulic oil of the drive circuit 25.

  The first hydraulic pump 22 and the second hydraulic pump 24 are variable displacement hydraulic pumps capable of flowing hydraulic oil in two directions. As shown in FIG. 2, the first hydraulic pump 22 has a first cylinder 22a driven by the hydraulic oil in the hydraulic oil supplement circuit 26, and a first direction for switching the flow direction of the hydraulic oil with respect to the first cylinder 22a. And a switching valve 22b. As shown in FIG. 2, the second hydraulic pump 24 is driven by the hydraulic oil of the hydraulic oil replenishment circuit 26, and the second direction for switching the flow direction of the hydraulic oil with respect to the second cylinder 24a. And a switching valve 24b. The first hydraulic pump 22 and the second hydraulic pump 24 can change the pump capacity between 0% and 100% with respect to the maximum pump capacity by operating the first cylinder 22a and the second cylinder 24a, respectively. Is possible. Further, the second hydraulic pump 24 can be driven by hydraulic oil flowing through the drive circuit 25, and also has a function as a hydraulic motor driven by hydraulic oil flowing through the drive circuit 25.

  The electric motor 23 can be driven by the electric power of the battery 11b and is configured to be able to rotate forward and reverse. Further, the electric motor 23 can generate electric power by a second hydraulic pump 24 that is driven as a hydraulic motor, and also has a function as a generator for generating electric power to be charged in the battery 11b.

In the drive circuit 25, a first hydraulic pump 22 and a second hydraulic pump 24 are connected in parallel to each other. A first hydraulic fluid passage 25 a is formed in the drive circuit 25 by connecting one port of each of the first hydraulic pump 22 and the second hydraulic pump 24 to one port of the hydraulic motor 21. In the drive circuit 25, a second hydraulic fluid passage 25 b is formed by connecting the other port of each of the first hydraulic pump 22 and the second hydraulic pump 24 to the other port of the hydraulic motor 21. . In addition, a pressure detection circuit 25c is configured between the first hydraulic fluid passage 25a and the second hydraulic fluid passage 25b connected to each port of the first hydraulic pump 22 of the drive circuit 25. The pressure detection circuit 25c can detect the discharge pressure of the hydraulic oil from the first hydraulic pump 22.
The drive circuit 25 adjusts the pump capacity of the first hydraulic pump 22 to 0% and adjusts the pump capacity of the second hydraulic pump 24 to be larger than 0%, so that the flow path of the hydraulic oil is second. It is set on the hydraulic pump 24 side. Further, the drive circuit 25 adjusts the pump capacity of the first hydraulic pump 22 to be larger than 0%, and adjusts the pump capacity of the second hydraulic pump 24 to 0%, so that the flow path of the hydraulic oil is reduced. It is set on the first hydraulic pump 22 side. In the present embodiment, switching in which the pump capacity is 0% in the first hydraulic pump 22 and the second hydraulic pump 24 corresponds to the flow path switching means of the present invention.

  The hydraulic oil replenishment circuit 26 has a pilot pump 26a driven by the engine 11a, and a hydraulic oil passage 26b is connected to the discharge side of the pilot pump 26a. The hydraulic fluid passage 26b includes a hydraulic fluid passage 26c connected to the first hydraulic fluid passage 25a of the drive circuit 25, a hydraulic fluid passage 26d connected to the second hydraulic fluid passage 25b, and a first hydraulic pressure. The first direction switching valve 22 b of the pump 22 and the second direction switching valve 24 b of the second hydraulic pump 24 are connected. The hydraulic oil passages 26c and 26d have check valves 26e for limiting the flow direction of the hydraulic oil from the hydraulic oil passage 26b side to the first hydraulic oil passage 25a side and the second hydraulic oil passage 25b side, respectively. , 26f. The hydraulic oil passage 26b is provided with a relief valve 26g for maintaining the pressure in the hydraulic oil supplement circuit 26 at a predetermined pressure.

  The controller 30 has a CPU, ROM, and RAM. When the controller 30 receives an input signal from a device connected to the input side, the CPU reads a program stored in the ROM based on the input signal, and stores a state detected by the input signal in the RAM. The output signal is transmitted to a device connected to the output side.

  On the output side of the controller 30, a battery 11b, a hydraulic motor 21, direction switching valves 22b and 24b, and an electric motor 23 are connected. The controller 30 transmits a signal related to the release of the brake of the rotating shaft to the hydraulic motor 21. The controller 30 transmits a signal related to switching between charging and discharging to the battery 11b. In addition, the controller 30 transmits a signal related to the release of the brake 21 a to the hydraulic motor 21. Further, the controller 30 transmits a signal related to the discharge amount of the hydraulic oil from the first hydraulic pump 22 and the second hydraulic pump 24 to the first direction switching valve 22b and the second direction switching valve 24b. Further, the controller 30 transmits a signal relating to driving or stopping of driving to the electric motor 23.

  On the input side of the controller 30, the battery 11 b, the electric motor 23, the operation unit 31 including a lever and a foot pedal operated by the operator, and the load of the load suspended on the hook 17 are detected and detected. An overload prevention device 32 for issuing a warning or stopping the crane work before the load exceeds the rated load is connected. The controller 30 includes a signal related to the charge amount of the battery 11b, a signal related to the operating state of the electric motor 23, an operation signal related to the operation direction and the operation amount of the operation unit 31, and the load of the load suspended on the hook 17 of the overload prevention device. A load signal is input.

  In the hydraulic actuator driving apparatus configured as described above, in the operation of winding up the normal winch 15, the pump capacity of the second hydraulic pump 24 is 0% with the electric motor 23 stopped. While adjusting the 2nd cylinder 24a, the 1st cylinder 22a is adjusted so that it may become the pump capacity | capacitance of the 1st hydraulic pump 22 according to the operation amount of the operation part 31, and the brake 21a is cancelled | released. As a result, the hydraulic oil discharged from the first hydraulic pump 22 flows through the drive circuit 25 to drive the hydraulic motor 21 and rotate the winch 15 in the winding direction, as shown in FIG.

  In the case where the winch 15 is wound up by the power of the battery 11b, such as when the engine 11a is stopped, the first cylinder 22a is adjusted so that the pump capacity of the first hydraulic pump 22 becomes 0%, The second cylinder 24a is adjusted so that the pump displacement of the second hydraulic pump 24 according to the operation amount of the operation unit 31 is set, and the brake 21a is released. As a result, the hydraulic oil discharged from the second hydraulic pump 24 flows through the drive circuit 25 to drive the hydraulic motor 21 and rotate the winch 15 in the winding direction, as shown in FIG.

  Further, in the case of the operation of lowering the winch 15 to lower the load suspended by the hook 17, the first cylinder 22a is adjusted so that the pump capacity of the first hydraulic pump 22 becomes 0%, The second cylinder 24a is adjusted so that the pump capacity of the second hydraulic pump 24 becomes a predetermined amount, and the brake 21a is released. Accordingly, the hydraulic motor 21 is driven by rotating the winch 15 with the weight of the load suspended from the hook 17. The hydraulic fluid discharged from the driven hydraulic motor 21 flows through the drive circuit 25 and drives the second hydraulic pump 24 as shown in FIG. The electric motor 23 rotating by driving the second hydraulic pump 24 functions as a generator to generate electric power, and the generated electric power is stored in the battery 11b.

  The controller 30 performs the hoisting control process of FIG. 7 when an operation for hoisting the winch 15 is input to the operation unit 31.

(Step S1)
In step S1, the CPU determines whether or not the operation input to the operation unit 31 is a winding operation. If it is a winding operation, the process proceeds to step S2.

(Step S2)
In step S1, when it is determined that the operation input to the operation unit 31 is a winding operation, in step S2, the CPU determines whether the charge amount of the battery 11b is equal to or greater than a predetermined charge amount. If the charge amount of the battery 11b is equal to or greater than the predetermined charge amount, the process proceeds to step S3. If the charge amount is less than the predetermined charge amount, the process proceeds to step S5.

(Step S3)
When it is determined in step S2 that the charge amount of the battery 11b is equal to or greater than the predetermined charge amount, in step 3, the CPU determines that the weight of the suspended load detected by the overload prevention device 32 is the capability of the second hydraulic pump 24. It is determined whether or not the weight is compatible. If the weight of the suspended load can be handled by the second hydraulic pump 24, the process proceeds to step S4. If the weight of the suspended load cannot be handled by the second hydraulic pump 24, the process proceeds to step S5.

(Step S4)
In step S3, when it is determined that the weight of the suspended load detected by the overload prevention device 32 can be handled by the capacity of the second hydraulic pump 24, the CPU drives the second hydraulic pump 24 in step S4. Then, the process returns to step S1.

(Step S5)
If it is determined in step 2 that the charge amount of the battery 11b is less than the predetermined charge amount, or the weight of the suspended load detected by the overload prevention device 32 in step S3 is the capacity of the second hydraulic pump 24. If it is determined that the response cannot be made, in step S5, the CPU drives the first hydraulic pump 22 and returns the process to step S1.

  Further, the controller 30 performs the lowering control process of FIG. 8 when an operation for lowering the winch 15 is input to the operation unit 31.

(Step S11)
In step S <b> 11, the CPU determines whether the operation input to the operation unit 31 is a lowering operation. If it is a lowering operation, the process proceeds to step S12.

(Step S12)
When it is determined in step S11 that the operation input to the operation unit 31 is a lowering operation, in step S12, the CPU determines whether or not the charge amount of the battery 11b is equal to or less than a predetermined charge amount that can be charged. If the charge amount of the battery 11b is less than or equal to a predetermined charge amount that can be charged, the process proceeds to step S13. If the charge amount is greater than the predetermined charge amount, the process proceeds to step S15.

(Step S13)
In step S12, when it is determined that the charge amount of the battery 11b is equal to or less than the predetermined charge amount, in step 13, the CPU determines that the weight of the suspended load detected by the overload prevention device 32 is the hydraulic pressure of the second hydraulic pump 24. It is determined whether or not the weight is drivable as a motor. When it is determined that the weight of the suspended load that can be driven by the second hydraulic pump 24 as a hydraulic motor is reached, the process proceeds to step S14, and the weight of the suspended load that cannot be driven by the second hydraulic pump 24 as a hydraulic motor. If it is determined, the process proceeds to step S15.

(Step S14)
In step S13, when it is determined that the weight of the suspended load can be driven using the second hydraulic pump 24 as a hydraulic motor, the CPU drives the second hydraulic pump 24 as a hydraulic motor in step S14. Return processing.

(Step S15)
If it is determined in step 12 that the charge amount of the battery 11b is greater than the predetermined charge amount, or in step S13, it is determined that the weight of the suspended load cannot drive the second hydraulic pump 24 as a hydraulic motor. In step S15, the CPU drives the first hydraulic pump 22 to lower the winch 15 and returns the process to step S11.

  As described above, according to the hydraulic actuator driving apparatus of the present embodiment, the winch 15 is rotated by the weight of the suspended load that is lowered when the lowering operation is performed, and the hydraulic motor 21 driven by the rotating winch 15 is used. The hydraulic oil in the drive circuit 25 is circulated, and power is generated by the pressure of the hydraulic oil that circulates in the drive circuit 25. Thereby, since the rotational force which arises when the weight of the hanging load which descend | falls is transmitted to the winch 15 can be utilized as electrical energy, it becomes possible to improve energy efficiency.

  A second hydraulic pump 24 that can be driven as a hydraulic motor connected in parallel to the first hydraulic pump 22 to the drive circuit 25; an electric motor 23 that is connected to the second hydraulic pump 24 and can be driven as a generator; And the rotational force generated when the weight of the suspended load descending when performing the lowering operation is transmitted to the winch 15 by switching the hydraulic fluid flow path of the drive circuit 25 to the second hydraulic pump 24 side. Has been converted. Accordingly, the first hydraulic pump 22 is used for switching between the engine 11a as a power source when driven as a hydraulic pump and the electric motor 23 to which an output when driven as a hydraulic motor is transmitted. Without requiring a special mechanism, it is possible to convert the rotational force generated when the weight of the suspended load to be transmitted to the winch 15 is converted into electric energy, and thus the manufacturing cost can be reduced.

  Moreover, the battery 11b which can store the electric power generated by driving the electric motor 23 is provided. Thereby, the electrical energy converted from the rotational force transmitted to the hydraulic motor 21 during the lowering operation can be stored in the battery 11b, so that the electrical energy can be used for other time zones and applications, so that the energy is effectively used. It can be used.

  Further, when performing the lowering operation, if the charged amount of the battery 11b is less than the predetermined charged amount, the second hydraulic pump 24 is driven as a hydraulic motor, and if the charged amount is equal to or greater than the predetermined charged amount. The first hydraulic pump 22 is driven. As a result, it is possible to prevent the battery 11b from being overcharged, thereby reducing the occurrence of failure of the battery 11b and extending the life of the battery 11b.

  Further, when performing the lowering operation, the weight of the load suspended on the hook 17 by the overload prevention device 32 is detected, and if the detected weight of the load is equal to or greater than a predetermined weight, 2 The hydraulic pump 24 is driven as a hydraulic motor, and the first hydraulic pump 22 is driven when the weight of the load is less than a predetermined weight. As a result, when the load on the winch 15 is small, the lowering operation is performed by driving the first hydraulic pump 22, and therefore the winch 15 can be lowered without being driven during the lowering operation. It is possible to prevent malfunctions such as failure.

  9 and 10 show another embodiment of the present invention. In addition, the same code | symbol is attached | subjected and shown to the component similar to the said embodiment.

As shown in FIG. 9, the hydraulic actuator driving device is an engine 11a or an electric motor, instead of the first hydraulic pump 22 driven by the engine 11a and the second hydraulic pump 24 driven by the electric motor 23. 23, a hydraulic pump 27 that is driven by switching the power, a piston 27a that is driven by the hydraulic oil of the hydraulic oil replenishment circuit 26, and a direction switching valve 27b that switches the flow direction of the hydraulic oil with respect to the piston 27a. Yes. The hydraulic pump 27 can change the pump capacity between 0% and 100% with respect to the maximum pump capacity by operating the piston 27a. The hydraulic pump 27 has a power switching mechanism 28 such as an electromagnetic clutch that switches power to the engine 11a or the electric motor 23, and is connected to the output side of the controller 30 as shown in FIG.
In the present embodiment, the power switching mechanism 28 for switching the power to the engine 11a or the electric motor 23 with respect to the hydraulic pump 27 corresponds to the power switching means of the present invention.

  The hydraulic actuator driving apparatus configured as described above can be operated in the same manner as in the above embodiment.

  As described above, according to the hydraulic actuator driving apparatus of the present embodiment, the power switching mechanism 28 that switches between transmitting the power of the engine 11a or transmitting the power of the electric motor 23 to the hydraulic pump 27 is provided. In addition, by switching the power to the electric motor 23 side, it is possible to regenerate the rotational force generated when the weight of the suspended load descending when performing the lowering operation is transmitted to the winch 15. As a result, it is possible to convert the rotational force generated by the weight of the suspended load descending by one hydraulic pump 27 to the winch 15 into electric energy, so that the manufacturing cost can be reduced by reducing the number of parts. It becomes possible.

  In the above-described embodiment, the hydraulic actuator driving device is applied to the winch driving device 20 that drives the winch 15 of the mobile crane 10. However, the present invention is not limited to this. For example, the inertial force when the turning speed is reduced in the turning operation of a swivel such as a crane or an aerial work vehicle may be converted into electric energy and used.

11a Engine 11b Battery 20 Winch drive device 21 Hydraulic motor 22 First hydraulic pump 23 Electric motor 24 Second hydraulic pump 25 Drive circuit 27 Hydraulic pump 28 Power switching mechanism 30 Controller 31 Operation unit 32 Overload prevention device

Claims (6)

A hydraulic actuator drive device comprising a hydraulic circuit configured by connecting a hydraulic pump and a hydraulic actuator in a closed circuit, driving the hydraulic pump by engine power, and driving the hydraulic actuator by hydraulic oil discharged from the hydraulic pump In
A hydraulic actuator comprising: a power generation unit configured to circulate hydraulic oil in a hydraulic circuit by a hydraulic actuator driven by an external force applied from a connected member, and to generate electric power by pressure of the hydraulic oil flowing through the hydraulic circuit. Drive device. The power generation means includes a generator capable of generating power using a hydraulic pump driven as a hydraulic motor by hydraulic oil flowing through a hydraulic circuit, and transmits engine power to the hydraulic pump or driven by hydraulic oil. The drive device for a hydraulic actuator according to claim 1, further comprising power switching means for switching whether to transmit the power of the hydraulic pump to the generator. The power generation means includes a hydraulic motor connected to the hydraulic circuit in parallel with the hydraulic pump, a generator capable of generating power using the hydraulic motor as power, and a flow for switching the hydraulic fluid passage of the hydraulic circuit to the hydraulic pump side or the hydraulic motor side. The hydraulic actuator driving device according to claim 1, further comprising: a path switching unit. The drive device for a hydraulic actuator according to claim 2 or 3, further comprising a battery capable of storing electric power generated by the generator. A storage amount detection means for detecting a storage amount of the battery;
In a state in which the hydraulic actuator is driven by an external force, if the stored amount detected by the stored amount detecting means is less than the predetermined stored amount, power is generated by the generator, and if the stored amount is greater than the predetermined stored amount The hydraulic actuator drive device according to claim 4, further comprising: a power storage control unit that drives the hydraulic pump with the power of the engine without performing power generation by the generator. In a state where the hydraulic actuator is driven by receiving an external force, if the external force received by the actuator is greater than or equal to a predetermined value, power is generated by a generator, and if the external force is less than a predetermined value, power is not generated by the generator. The hydraulic actuator drive device according to any one of claims 2 to 5, further comprising operation switching control means for driving the hydraulic pump with engine power.

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