阅读说明：本技术 液压装置以及液压装置的控制方法 (Hydraulic device and control method for hydraulic device ) 是由 饭泉仁美 金谷顕一 西田宏幸 于 2020-02-10 设计创作，主要内容包括：本发明提供一种可提升耐久性并以高的可靠性进行运行的液压装置及液压装置的控制方法。液压装置通过流体供给部将已被存积在流体存积部的工作流体,朝输出由工作流体所产生的动力的动力输出部供给。通过无刷马达来驱动流体供给部。设置可切换成第一状态及第二状态的旁通流路部,在所述第一状态中从流体供给部朝流体存积部供给工作流体,在所述第二状态中将流体供给部与流体存积部隔断。进行如下控制的至少一者：在无刷马达的启动后将旁通流路部从第一状态切换成第二状态的控制、及在无刷马达的停止时将旁通流路部从第二状态切换成第一状态的控制。通过防逆流阀来防止工作流体从动力输出部朝旁通流路部的逆流。(The invention provides a hydraulic device and a control method of the hydraulic device, which can improve durability and operate with high reliability. The hydraulic device supplies the working fluid stored in the fluid storage unit to a power output unit that outputs power generated by the working fluid, via the fluid supply unit. The fluid supply portion is driven by a brushless motor. A bypass flow path section is provided which is switchable between a first state in which a working fluid is supplied from a fluid supply section to a fluid storage section and a second state in which the fluid supply section is blocked from the fluid storage section. Performing at least one of the following controls: the control unit switches the bypass flow path unit from the first state to the second state after the brushless motor is started, and switches the bypass flow path unit from the second state to the first state when the brushless motor is stopped. The backflow of the working fluid from the power output section to the bypass flow path section is prevented by the backflow prevention valve.)

1. A hydraulic device, comprising:

a fluid storage unit for storing a working fluid;

a power output unit that outputs power generated by the working fluid;

a fluid supply unit configured to supply the working fluid stored in the fluid storage unit to the power output unit;

a brushless motor that drives the fluid supply unit;

a bypass flow path portion switchable between a first state in which a working fluid is supplied from the fluid supply portion to the fluid storage portion and a second state in which the fluid supply portion is blocked from the fluid storage portion;

a control unit that performs at least one of the following controls: control for switching the bypass flow path section from the first state to the second state after start-up of the brushless motor, and control for switching the bypass flow path section from the second state to the first state when the brushless motor is stopped; and

and a backflow prevention valve that prevents backflow of the working fluid from the power output section to the bypass flow path section.

2. The hydraulic apparatus according to claim 1, wherein the control portion includes:

a start receiving unit that receives a start instruction of the power output unit;

a first rotation control unit that gives a first rotation signal for rotating the brushless motor in a predetermined direction in response to the start instruction received by the start receiving unit; and

and a blocking control unit configured to switch the bypass flow path unit from the first state to the second state after a rotation speed of the brushless motor has increased to a predetermined value.

3. The hydraulic device of claim 2, wherein the brushless motor is a sensorless brushless motor without a position sensor.

4. The hydraulic apparatus according to any one of claims 1 to 3, wherein the control portion includes:

a stop receiving unit that receives a stop command from the power output unit; and

and an opening control unit that switches the bypass flow path unit from the second state to the first state in response to the stop receiving unit receiving a stop command.

5. The hydraulic apparatus according to claim 4, wherein the control portion further includes a second rotation control portion that gives a second rotation signal corresponding to a rotation direction opposite to the rotation direction of the brushless motor to the brushless motor in response to reception of the stop instruction by the stop receiving portion to stop rotation of the brushless motor.

6. A control method of a hydraulic apparatus, characterized by comprising:

supplying the working fluid stored in the fluid storage unit to a power output unit that outputs power generated by the working fluid, via the fluid supply unit;

driving the fluid supply unit by a brushless motor;

switching a bypass flow path section between a first state in which a working fluid is supplied from the fluid supply section to the fluid storage section and a second state in which the fluid supply section is blocked from the fluid storage section; and

preventing, by a backflow prevention valve, a backflow of the working fluid from the power output section to the bypass flow path section; and is

The step of switching the bypass flow path section includes at least one of the following steps: the bypass flow path unit is switched from the first state to the second state after the brushless motor is started, and the bypass flow path unit is switched from the second state to the first state when the brushless motor is stopped.

Technical Field

The present invention relates to a hydraulic apparatus and a control method for the hydraulic apparatus.

Background

A work machine such as a truck is provided with a hydraulic device for driving a support arm by hydraulic pressure. For example, patent document 1 describes a hydraulic device including a hydraulic cylinder, a pump, and an electric motor. In the hydraulic device, the motor drives the pump in response to a user of the work machine operating the remote controller. Thus, the pump supplies the hydraulic fluid to the hydraulic cylinder that operates the support arm of the cargo bed.

In the hydraulic device, a Direct Current (DC) brush motor is generally used as an electric motor. However, the durability of the brush motor is limited by the life of the brush, and therefore, the durability of the hydraulic device using the brush motor is not high. Therefore, in recent years, it has been required to improve the durability of the hydraulic device.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent laid-open No. 2007-223419

Disclosure of Invention

[ problems to be solved by the invention ]

It is conceivable to use a brushless motor instead of the brush motor as the electric motor, whereby the durability of the hydraulic device can be improved. However, if the hydraulic device is configured using a brushless motor, there is a possibility that a failure in starting due to insufficient torque, a problem of pressurization (pressurization) of piping, and the like may occur. Therefore, the hydraulic device may not be operated with high reliability. Here, the pressurization refers to a state in which the pressure in the pipe increases when the brushless motor is stopped.

The invention aims to provide a hydraulic device which can improve durability and operate with high reliability.

[ means for solving problems ]

An aspect according to an aspect of the invention relates to a hydraulic apparatus including: a fluid storage unit for storing a working fluid; a power output unit that outputs power generated by the working fluid; a fluid supply unit configured to supply the working fluid stored in the fluid storage unit to the power output unit; a brushless motor that drives the fluid supply unit; a bypass flow path portion switchable between a first state in which a working fluid is supplied from the fluid supply portion to the fluid storage portion and a second state in which the fluid supply portion is blocked from the fluid storage portion; a backflow prevention valve that prevents a backflow of the working fluid from the power output section toward the bypass flow path section; and a control unit that performs at least one of the following controls: the control unit includes control for switching the bypass flow path unit from the first state to the second state after the brushless motor is started, and control for switching the bypass flow path unit from the second state to the first state when the brushless motor is stopped.

Another aspect of the present invention relates to a method for controlling a hydraulic apparatus, including: supplying the working fluid stored in the fluid storage unit to a power output unit that outputs power generated by the working fluid, via the fluid supply unit; a step of driving the fluid supply section by a brushless motor; preventing, by a backflow prevention valve, a backflow of the working fluid from the power output section to a bypass flow path section; and switching the bypass flow path unit between a first state in which the working fluid is supplied from the fluid supply unit to the fluid storage unit and a second state in which the fluid supply unit is blocked from the fluid storage unit; and the step of switching the bypass flow path section includes at least one of the following steps: the bypass flow path unit is switched from the first state to the second state after the brushless motor is started, and the bypass flow path unit is switched from the second state to the first state when the brushless motor is stopped.

[ Effect of the invention ]

According to the present invention, it is possible to improve the durability of the hydraulic device and to operate the hydraulic device with high reliability.

Drawings

Fig. 1 is a diagram showing a configuration of a hydraulic apparatus according to an embodiment of the present invention.

Fig. 2 is a block diagram showing a configuration of the control unit of fig. 1.

Fig. 3 is a timing chart for explaining an example of the operation of the control unit.

Fig. 4 is a flowchart showing an algorithm of the hydraulic device control process by the hydraulic device control program.

Description of the symbols

1: starting receiving part

2: stop receiving part

3: forward rotation control unit

4: inversion control unit

5: partition control unit

6: opening control part

7: output control unit

10: fluid reservoir

20: fluid supply unit

30: brushless motor

40: bypass flow path part

41: bypass pipe

42: bypass valve

50: anti-reflux valve

60: power take-off

61. 62: fluid pressure actuator

63. 64: directional control valve

70: control unit

71：CPU

72: memory device

100: hydraulic device

101: operation part

102: piping

Detailed Description

(1) Construction of hydraulic devices

A hydraulic apparatus and a method for controlling the hydraulic apparatus according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the hydraulic device is provided in a working machine such as a truck, but the embodiment is not limited thereto, and may be provided in another machine. Fig. 1 is a diagram showing a configuration of a hydraulic apparatus according to an embodiment of the present invention. As shown in fig. 1, the hydraulic apparatus 100 includes: a fluid storage unit 10, a fluid supply unit 20, a brushless motor 30, a bypass flow path unit 40, a valve 50 for preventing reverse flow, a power output unit 60, and a control unit 70.

The fluid reservoir 10 is, for example, a tank for storing a working fluid (hereinafter, simply referred to as a fluid) such as oil. The fluid supply unit 20 is, for example, a pump, and pressure-feeds the fluid stored in the fluid storage unit 10 to the power output unit 60. The brushless motor 30 drives the fluid supply portion 20. In the present embodiment, the brushless motor 30 is a sensorless brushless motor and does not have a position sensor such as a Hall (Hall) sensor. The embodiment is not limited to this, and the brushless motor 30 may be a brushless motor with a sensor.

The bypass flow path portion 40 includes a bypass pipe 41 and a bypass valve 42. The bypass pipe 41 is connected between the fluid reservoir 10 and the fluid supply unit 20 so as to return the fluid pumped by the fluid supply unit 20 to the fluid reservoir 10. The bypass valve 42 is inserted into the bypass pipe 41 and can be switched between an open state in which the bypass pipe 41 is opened and a blocked state in which the bypass pipe 41 is blocked. The valve 50 is inserted between the power output unit 60 and the fluid supply unit 20 and the bypass passage unit 40, and prevents the fluid from the power output unit 60 from flowing backward to the bypass passage unit 40.

The power output portion 60 outputs power generated by the fluid to, for example, a support arm of the cargo bed. Specifically, the power output unit 60 includes: a fluid pressure actuator 61, a fluid pressure actuator 62, and a directional control valve 63, a directional control valve 64. In this example, the fluid pressure actuator 61 is a double-acting tilt cylinder (tilting cylinder) that is operated by fluid pressure and tilts the support arm of the cargo bed. The directional control valve 63 is provided between the fluid pressure actuator 61 and the fluid reservoir 10 and the valve 50 for preventing reverse-flow, and controls the operation of the fluid pressure actuator 61.

In this example, the fluid pressure actuator 62 is a single-acting lift cylinder (lift cylinder) that is operated by fluid pressure to lift and lower the support arm of the cargo bed. The directional control valve 64 is provided between the fluid pressure actuator 62 and the fluid reservoir 10 and the valve 50 for preventing reverse-flow, and controls the operation of the fluid pressure actuator 62. The user can instruct the operation of the fluid pressure actuators 61 and 62 by operating the operation unit 101 such as a remote controller.

The Control Unit 70 is, for example, an Electronic Control Unit (ECU) and includes a Central Processing Unit (CPU) 71 and a memory 72. The CPU 71 controls the operations of the brushless motor 30, the bypass valve 42, the direction control valve 63, and the direction control valve 64 in accordance with instructions from the operation unit 101. A hydraulic device control program for controlling the operation of the CPU 71 is stored in the memory 72. The detailed configuration of the control unit 70 will be described below.

(2) Control unit

Fig. 2 is a block diagram showing a configuration of the control unit 70 of fig. 1. As shown in fig. 2, the control unit 70 includes a start receiving unit 1, a stop receiving unit 2, a normal rotation control unit 3, a reverse rotation control unit 4, a blocking control unit 5, an opening control unit 6, and an output control unit 7 as functional units. The CPU 71 of fig. 1 executes a hydraulic device control program that has been stored in the memory 72, thereby realizing functional portions of the control portion 70. A part or all of the functional units of the control unit 70 may be realized by hardware such as an electronic circuit.

The activation receiving unit 1 receives a command (hereinafter, referred to as an activation command) for activating either the fluid pressure actuator 61 or the fluid pressure actuator 62 of fig. 1 from the operation unit 101. The stop receiving unit 2 receives a command (hereinafter, referred to as a stop command) for stopping the activation of the fluid pressure actuators 61 and 62 from the operation unit 101.

In response to the start receiving unit 1 receiving the start instruction, the forward rotation control unit 3 gives a forward rotation signal for rotating the brushless motor 30 in the forward direction. In response to the stop receiving unit 2 receiving the stop command, the inversion control unit 4 supplies an inversion signal corresponding to the inversion to the brushless motor 30. The normal rotation control unit 3 and the reverse rotation control unit 4 are examples of a first rotation control unit and a second rotation control unit, respectively.

The blocking control unit 5 controls the bypass valve 42 to be in the blocking state in response to the start receiving unit 1 receiving the start command. The opening control unit 6 controls the bypass valve 42 to be in the open state in response to the stop receiving unit 2 receiving the stop command. The output control unit 7 specifies the operations of the fluid pressure actuators 61 and 62 based on the commands given from the operation unit 101, and controls the directional control valves 63 and 64 so that the specified operations are executed.

Fig. 3 is a timing chart for explaining an example of the operation of the control unit 70. As shown in fig. 3, at initial time t0, the start of fluid pressure actuators 61 and 62 is stopped, the rotation of brushless motor 30 is stopped, and bypass valve 42 is in the open state.

At time t1, the user operates the operation unit 101 to instruct the desired activation of the fluid pressure actuators 61 and 62, thereby giving an activation instruction to the activation accepting unit 1. In this case, the forward rotation control unit 3 gives a forward rotation signal to the brushless motor 30 so as to rotate at a predetermined low rotation speed (for example, a fixed speed of 500rpm or less). After the speed of the brushless motor 30 reaches the low rotation speed, the low rotation speed is maintained until a time point t 2.

At a time point t2, the shut-off control portion 5 controls the bypass valve 42 so as to be in the shut-off state. The time from time t1 to time t2 is, for example, 0.1 second or more and 0.3 second or less. At time t2, the forward rotation control unit 3 further gives a forward rotation signal to the brushless motor 30. After the rotational speed of the brushless motor 30 reaches the maximum speed, the maximum speed is maintained until the stop of the start of the fluid pressure actuators 61, 62 is instructed.

At time t3, the user operates the operation unit 101 to instruct the desired stop of the start of the fluid pressure actuators 61 and 62, thereby giving a stop instruction to the stop receiving unit 2. In this case, the opening control portion 6 controls the bypass valve 42 so as to be in the open state. At time t3, the reverse rotation control unit 4 gives a reverse rotation signal to the brushless motor 30. Thereby, the forward rotation speed of the brushless motor 30 decreases, and the rotation speed becomes 0 at time t 4. At a time point t4, the reverse rotation control portion 4 stops the control of the brushless motor 30.

(3) Hydraulic device control process

Fig. 4 is a flowchart showing an algorithm of the hydraulic device control process by the hydraulic device control program. The hydraulic device control process will be described below with reference to the control unit 70 of fig. 2 and the flowchart of fig. 4. In the initial state, the start of the fluid pressure actuators 61 and 62 is stopped, the rotation of the brushless motor 30 is stopped, and the bypass valve 42 is opened.

First, the activation accepting unit 1 determines whether or not an activation instruction is accepted from the operation unit 101 (step S1). When the start instruction is not received, the start receiving unit 1 waits until the start instruction is received. When the start instruction is received, the output control unit 7 controls the directional control valve 63 and the directional control valve 64 so that the operation corresponding to the received start instruction can be performed (step S2). Further, the forward rotation control unit 3 gives a forward rotation signal to the brushless motor 30 (step S3).

Next, the blocking control unit 5 determines whether or not the rotation speed of the brushless motor 30 has reached a predetermined low rotation speed (step S4). When the rotation speed of the brushless motor 30 does not reach the low rotation speed, the blocking control unit 5 returns to step S3. Until the rotation speed of the brushless motor 30 reaches the low rotation speed, steps S3, S4 are repeated. When the rotation speed of the brushless motor 30 has reached the low rotation speed, the normal rotation control unit 3 maintains the rotation speed of the brushless motor 30 at the low rotation speed in step S3.

In this example, the blocking control unit 5 determines that the rotation speed of the brushless motor 30 has reached the low rotation speed by the elapse of a predetermined time (for example, 0.1 seconds or more and 0.3 seconds or less) from the reception of the start command in step S1. Therefore, in step S4, the blocking control unit 5 determines whether or not a predetermined time has elapsed since the start command was received in step S1, and waits until the time has elapsed without the elapse of the predetermined time.

When the rotation speed of the brushless motor 30 has reached the predetermined low rotation speed in step S4 (when the predetermined time has elapsed), the blocking control unit 5 switches the bypass valve 42 to the blocking state (step S5). Further, the forward rotation control unit 3 increases the forward rotation signal of the brushless motor 30 (step S6). Thereby, the rotation speed of the brushless motor 30 is increased.

Thereafter, the stop receiving unit 2 determines whether or not a stop instruction is received from the operation unit 101 (step S7). When the stop instruction is not received, the stop receiving unit 2 returns to step S6. Until the stop instruction is accepted, steps S6 and S7 are repeated. When the rotation speed of the brushless motor 30 has reached the maximum speed, the normal rotation control unit 3 maintains the rotation speed of the brushless motor 30 at the maximum speed in step S6.

When the stop command is received in step S7, the on control unit 6 switches the bypass valve 42 to the on state (step S8). Further, the reverse rotation control unit 4 gives a reverse rotation signal to the brushless motor 30 (step S9). Thereby, the rotation speed of the brushless motor 30 is reduced. Then, the reverse rotation control unit 4 determines whether or not the rotation speed of the brushless motor 30 has become 0, that is, whether or not the rotation of the brushless motor 30 has stopped (step S10).

When the rotation of the brushless motor 30 is not stopped, the reverse rotation control unit 4 returns to step S9. Until the rotation of the brushless motor 30 is stopped, steps S9 and S10 are repeated. When the rotation of the brushless motor 30 is stopped, the reverse rotation control unit 4 ends the hydraulic device control process.

(4) Effect

In the hydraulic apparatus 100 of the present embodiment, the working fluid stored in the fluid storage portion 10 is supplied to the power output portion 60 by the fluid supply portion 20. The fluid supply section 20 is driven by the brushless motor 30. According to the above configuration, since the brushless motor 30 is used as the motor, the durability of the motor is not limited by the life of the brush. Therefore, the durability of the hydraulic device 100 is improved.

Further, a bypass flow path portion 40 is provided, and the bypass flow path portion 40 is switchable between an open state in which the working fluid is supplied from the fluid supply portion 20 to the fluid storage portion 10 and a blocked state in which the fluid supply portion 20 is blocked from the fluid storage portion 10. When the start receiving unit 1 receives the start command of the power output unit 60, the forward rotation control unit 3 gives a forward rotation signal to the brushless motor 30, and the brushless motor 30 rotates in the forward direction.

In the initial state, since the bypass flow path portion 40 is in the open state, the fluid from the fluid supply portion 20 passes through the bypass flow path portion 40 and returns to the fluid storage portion 10 before the rotation speed of the brushless motor 30 increases to a predetermined low rotation speed. The backflow of the working fluid from the power output portion 60 to the bypass flow path portion 40 is prevented by the backflow prevention valve 50. Here, since the brushless motor 30 has a low rotation speed, the flow rate of the fluid passing through the bypass flow path portion 40 is small, and thus the generation of fluid noise can be prevented.

After the rotation speed of brushless motor 30 has increased to the low rotation speed, bypass flow path unit 40 is switched from the open state to the blocked state by blocking control unit 5. In this case, when the power output unit 60 is started, the working fluid is supplied to the power output unit 60 after the brushless motor 30 has rotated at a sufficient rotation speed, and therefore, a failure in starting the brushless motor 30 due to insufficient torque can be avoided. Therefore, as the brushless motor 30, it is not necessary to use a motor having a large capacity of an inverter corresponding to a high starting torque, and a motor having a small capacity of an inverter can be used.

In addition, since failure of the start-up of the brushless motor 30 due to insufficient torque is avoided, as the brushless motor 30, a sensorless type brushless motor 30 having no position sensor may be used. In this case, the brushless motor 30 and the fluid supply unit 20 can be connected with fewer wires.

When the stop receiving unit 2 receives a stop command from the power output unit 60, the bypass passage unit 40 is switched from the blocked state to the open state by the opening control unit 6. Therefore, the pipe 102 connecting the fluid supply unit 20 and the power output unit 60 is prevented from being pressurized. This reduces the burden on the pipe 102.

When the stop receiving unit 2 receives the stop command from the power output unit 60, the reverse rotation control unit 4 gives a reverse signal to the brushless motor 30 to stop the rotation of the brushless motor 30. In this case, after the stop of power output unit 60, the rotation of brushless motor 30 is stopped in a shorter time. This can more reliably prevent the pipe 102 from being pressurized. As a result of these configurations, it is possible to improve the durability of the hydraulic apparatus 100 and to operate the hydraulic apparatus 100 with high reliability.

(5) Other embodiments

(a) In the above embodiment, the first control of switching the bypass flow path unit 40 from the open state to the blocked state after the start of the brushless motor 30 and the second control of switching the bypass flow path unit 40 from the blocked state to the open state when the brushless motor 30 is stopped are performed, but the embodiment is not limited to this. Only one of the first control and the second control may be performed without performing the other control.

(b) In the above embodiment, the reverse signal is given to the brushless motor 30 when the power output unit 60 is stopped, but the embodiment is not limited thereto. When the power output unit 60 is stopped, the brushless motor 30 may be naturally stopped without giving a reverse signal to the brushless motor 30.

(c) In the above embodiment, the power output unit 60 includes the plurality of fluid pressure actuators 61 and 62, but the embodiment is not limited thereto. The power take-off 60 may also comprise a fluid pressure actuator.

(6) Form of the composition

The hydraulic apparatus according to the first aspect may include:

a fluid storage unit for storing a working fluid;

a power output unit that outputs power generated by the working fluid;

a fluid supply unit configured to supply the working fluid stored in the fluid storage unit to the power output unit;

a brushless motor that drives the fluid supply unit;

a bypass flow path section that is switchable between a first state in which a working fluid is supplied from the fluid supply section to the fluid storage section and a second state in which the fluid supply section is blocked from the fluid storage section;

a control unit that performs at least one of the following controls: control for switching the bypass flow path section from the first state to the second state after start-up of the brushless motor, and control for switching the bypass flow path section from the second state to the first state when the brushless motor is stopped; and

and a backflow prevention valve that prevents backflow of the working fluid from the power output section to the bypass flow path section.

In the hydraulic device, the working fluid stored in the fluid storage portion is supplied by the fluid supply portion to the power output portion that outputs the power generated by the working fluid. The fluid supply portion is driven by a brushless motor. A bypass flow path section is provided which is switchable between a first state in which a working fluid is supplied from a fluid supply section to a fluid storage section and a second state in which the fluid supply section is blocked from the fluid storage section. Performing at least one of the following steps: the bypass flow path section is switched from the first state to the second state after the brushless motor is started, and the bypass flow path section is switched from the second state to the first state when the brushless motor is stopped. The backflow of the working fluid from the power output section to the bypass flow path section is prevented by the backflow prevention valve.

According to the above configuration, a brushless motor can be used as the electric motor. Thus, the durability of the motor is not limited by the life of the brush. Therefore, the durability of the hydraulic device is improved.

In addition, when the bypass flow path portion is switched from the first state to the second state after the brushless motor is started, a high torque is not applied to the electric motor immediately after the brushless motor is started. Thereby, the brushless motor can start to rotate smoothly. After the brushless motor starts rotating, the working fluid stored in the fluid storage unit is supplied to the power output unit by the fluid supply unit. Therefore, failure in starting the brushless motor caused by insufficient torque can be avoided.

On the other hand, when the bypass flow path portion is switched from the second state to the first state at the time of stopping the brushless motor, the working fluid supplied from the fluid supply portion passes through the bypass flow path portion and returns to the fluid storage portion. In this case, the piping connecting the fluid supply unit and the power output unit is not pressurized, and therefore the burden on the piping is reduced.

Therefore, by performing at least one of the controls of the bypass passage portion, the reliability of the hydraulic device is improved. As a result, the durability of the hydraulic device can be improved and the hydraulic device can be operated with high reliability.

(second item) the hydraulic apparatus according to the first item, wherein

The control unit may include:

a start receiving unit that receives a start instruction of the power output unit;

a first rotation control unit that gives a first rotation signal for rotating the brushless motor in a predetermined direction in response to the start instruction received by the start receiving unit; and

and a blocking control unit configured to switch the bypass flow path unit from the first state to the second state after a rotation speed of the brushless motor has increased to a predetermined value.

In this case, when the power output unit is started, the working fluid is supplied to the power output unit after the brushless motor has rotated at a sufficient rotation speed. Therefore, the failure of the start-up of the brushless motor due to the insufficient torque can be more surely avoided.

(third item) the hydraulic apparatus according to the second item, wherein

The brushless motor may also be a sensorless type brushless motor without a position sensor.

In this case, since failure of the start of the brushless motor due to insufficient torque is avoided, as the brushless motor, a sensorless type brushless motor having no position sensor can be used. This allows the brushless motor to be connected to the fluid supply unit with fewer wires. As a result, the durability and reliability of the hydraulic device can be further improved.

(fourth) the hydraulic apparatus according to any one of the first to third aspects, wherein

The control unit may include:

a stop receiving unit that receives a stop command from the power output unit; and

and an opening control unit that switches the bypass flow path unit from the second state to the first state in response to the stop receiving unit receiving a stop command.

In this case, the bypass flow path portion is switched from the second state to the first state when the power output portion is stopped. This can more reliably prevent the occurrence of a pressure increase in the pipe connecting the fluid supply unit and the power output unit.

(fifth item) the hydraulic apparatus according to the fourth item, wherein

The control unit may further include a second rotation control unit that, in response to the stop instruction being received by the stop receiving unit, gives a second rotation signal corresponding to a rotation direction opposite to the rotation direction of the brushless motor to stop the rotation of the brushless motor.

In this case, after the stop of the power output portion, the rotation of the brushless motor is stopped in a shorter time. This can more reliably prevent the occurrence of a pressure increase in the pipe connecting the fluid supply unit and the power output unit.

(sixth aspect) the method for controlling a hydraulic apparatus according to the other aspect includes:

supplying the working fluid stored in the fluid storage unit to a power output unit that outputs power generated by the working fluid, via the fluid supply unit;

driving the fluid supply unit by a brushless motor;

switching a bypass flow path section between a first state in which a working fluid is supplied from the fluid supply section to the fluid storage section and a second state in which the fluid supply section is blocked from the fluid storage section; and

preventing, by a backflow prevention valve, a backflow of the working fluid from the power output section to the bypass flow path section; and is

The step of switching the bypass flow path portion may include at least one of the following steps: the bypass flow path unit is switched from the first state to the second state after the brushless motor is started, and the bypass flow path unit is switched from the second state to the first state when the brushless motor is stopped.

According to the control method of the hydraulic apparatus, a brushless motor may be used as the electric motor. Thus, the durability of the motor is not limited by the life of the brush. Therefore, the durability of the hydraulic device is improved. In addition, at least one of the following controls is performed: the control unit switches the bypass flow path unit from the first state to the second state after the brushless motor is started, and switches the bypass flow path unit from the second state to the first state when the brushless motor is stopped. Thereby, the reliability of the hydraulic device is improved. As a result, the durability of the hydraulic device can be improved and the hydraulic device can be operated with high reliability.