JP2007032799A - Fluid-pressure control circuit with regeneration function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid-pressure control circuit with a regeneration function having a simple structure which can be made small and compact. <P>SOLUTION: A fluid pressure pump motor 3 is adopted as a capacity-variable fluid pressure pump motor 3, a flywheel 4 is provided between the fluid pressure pump motor 3 and a motor 2, and a control means 5 is provided to control a inclined rotation angle of the capacity-variable fluid pressure pump motor 3 based on the number of rotation of the flywheel 4 and the discharge quantity requested for the pump motor 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fluid pressure control circuit with a regenerative function capable of recovering energy applied to a load.

  In forklifts, etc., hydraulic pressure is used to lift the load against gravity, but when lowering the lifted load, it is possible to recover the energy stored in the hydraulic fluid returned to the hydraulic tank. For example, Patent Document 1 proposes an energy recovery device for that purpose, that is, a fluid pressure control circuit with a regeneration function.

  In this patent document 1, as energy saving means usable in an energy recovery device, a. An accumulator, b. Flywheel, c. We are proposing an energy recovery device that raises the battery and eventually uses the battery.

  However, in the case of using a battery, a multiple conversion process is required in which kinetic energy is temporarily converted into electrical energy by a generator and stored in the battery, and then converted into kinetic energy by an electric motor. However, there is a drawback that energy loss is large, and the apparatus and control are complicated, and there is a point unsuitable for simplification.

Further, when using a battery, as described in Patent Document 1, there is a problem that the responsiveness is low, and particularly, it is difficult to instantaneously collect large energy generated in a cargo handling device or the like.
JP 2000-136806 A (FIGS. 1 and 6)

  An object of the present invention is to provide a fluid pressure control circuit with a regenerative function that can reduce the energy loss and can be simplified, and has good response.

The fluid pressure control circuit with a regeneration function of the present invention is a fluid pressure control circuit with a regeneration function, comprising a fluid pressure actuator, a motor, and a fluid pressure pump motor, and regenerating the driven energy of the fluid pressure actuator,
The fluid pressure pump motor is a variable displacement fluid pressure pump motor, a flywheel is interposed between the fluid pressure pump motor and the motor, and the tilt angle of the variable displacement fluid pressure pump motor is set to the rotational speed of the flyhole. And a control means for controlling based on the discharge amount required for the pump motor.

  Here, the fluid pressure control circuit includes not only hydraulic oil generally used in a hydraulic circuit but also water and a polymer compound fluid as a working fluid, and various controls using the pressure of such a fluid. This means a circuit that performs the above.

  The driven energy of the fluid pressure actuator means energy received when the fluid pressure actuator is driven in reverse by the load driven by the fluid pressure actuator.

  As a specific example, in a hydraulic forklift, when a load lifted by hydraulic pressure is lowered due to gravity, the energy is included in the hydraulic oil returned from the hydraulic cylinder of the hydraulic forklift to the hydraulic tank.

  The fluid pressure control circuit of the present invention uses a flywheel as the energy saving means, and the load is driven by a combination of this flywheel, a variable capacity fluid pressure pump motor, and the control means having the above function. In some cases, the energy of the flywheel is used to control the tilt angle of the variable displacement fluid pressure pump motor to supply the required amount of fluid to the fluid pressure actuator. The fluid from the pressure actuator is recirculated by a predetermined amount, and the driven energy is stored in the flywheel.

  Therefore, according to this fluid pressure control circuit, the conventional fluid pressure pump motor is of a variable displacement type, a flywheel is provided between the motor and the motor, and control means for performing predetermined control (this does not require a space). Since the regenerative function is achieved only by providing the above-mentioned and there is no multiple energy conversion as in the conventional example, the energy loss is small, the circuit is simple, the simplification is possible, and the responsiveness is good.

  In addition, the combination of this flywheel, variable displacement fluid pressure pump motor, and control means can reduce the discharge amount of the variable displacement fluid pressure pump motor not only when the fluid pressure actuator is driven but also when driven by the fluid pressure actuator. Since it can be controlled to a desired value, meter-out control can be performed while eliminating the need for a counterbalance valve and a throttle valve that regulate the reflux speed as in the prior art.

  Hereinafter, embodiments (examples) of the present invention will be described with reference to the drawings.

  1 is a circuit diagram showing an example of a fluid pressure control circuit with a regenerative function of the present invention (when holding a load), FIG. 2 is a circuit diagram when the load of the fluid pressure control circuit of FIG. 1 is increased, and FIG. It is a circuit diagram at the time of load fall of 1 fluid pressure control circuit.

  The fluid pressure control circuit 10 with a regenerative function is exemplified to explain the basic function, and is like a forklift that raises the load W against gravity by the fluid pressure cylinder 1 that is a fluid pressure actuator. It is built into a fluid pressure device.

  The fluid pressure control circuit 10 includes a motor 2 that rotates the fluid pressure cylinder 1, the flywheel 4 and the variable displacement fluid pressure pump motor 3 within a predetermined rotational speed range, and a pump for driving the fluid pressure cylinder 1. The fluid pressure pump motor 3 that functions as a motor when driven from the fluid pressure cylinder 1, the flywheel 4 that functions as energy storage means in the circuit 10, the tilt angle of the fluid pressure pump motor 3, etc. And a fluid tank 6 for storing the working fluid used in this circuit.

  The circuit of the working fluid enters the fluid pressure pump motor 3 from the fluid tank 6 through the check valve CV1, and the main circuit 10a from the fluid pressure pump motor 3 to the fluid pressure cylinder 1 through the check valve CV2; A reflux circuit 10b bypassed to the main circuit 10a and a return circuit 10c for returning the working fluid discharged from the fluid pressure pump motor 3 to the fluid pressure tank 6 are provided.

  The two check valves CV1 and CV2 installed in the main circuit 10a are a working fluid in the direction from the fluid pressure tank 6 to the fluid pressure pump motor 3 and from the fluid pressure pump motor 3 to the fluid pressure cylinder 1. Is allowed, but is prevented from flowing in the opposite direction.

  The recirculation circuit 10b bypasses between the check valve CV1 of the main circuit 10a and the fluid pressure pump motor 3, and between the check valve CV2 and the fluid pressure cylinder 1, and includes an open / close solenoid valve 5d. It has. This open / close solenoid valve 5d permits the return from the fluid pressure cylinder 1 to the fluid pressure pump motor 3 when the power is on, and prevents the flow when the power is off.

  The return circuit 10c branches from between the fluid pressure pump motor 3 and the check valve CV2 of the main circuit 10a to reach the fluid pressure tank 6, and includes an open / close electromagnetic valve 5e in the circuit. The open / close electromagnetic valve 5e permits the return from the fluid pressure pump motor 3 to the fluid pressure tank 6 when the power is off, and prevents the flow when the power is on.

  The control means 5 includes a manual operation lever 5b, a control unit 5a, and a rotation speed sensor 5c for measuring the rotation speed of the flywheel 4, and performs on / off control of the above-described opening / closing electromagnetic valve 5d and opening / closing electromagnetic valve 5e. The tilt angle of the variable displacement fluid pressure pump motor 3 is controlled based on the rotational speed of the flyhole 4 and the discharge amount required for the pump motor 3, that is, the speed required for the load W. .

 The rotational speed sensor may measure the rotational speed of the fluid pressure pump motor 3.

  Regarding the operation mode of the fluid pressure control circuit 10 with the regenerative function having such a configuration, FIG. 1 showing a state when the load is held, FIG. 2 showing a state when the load is increased, and a state when the load of the fluid pressure control circuit is lowered. This will be described using FIG. 3 in order.

  In the load holding state of FIG. 1, the operation lever 5b is in a neutral state, the open / close solenoid valve 5d of the reflux circuit 10b is turned off, and the reflux from the fluid pressure cylinder 1 to the fluid pressure pump motor 3 is prevented. Yes. The open / close solenoid valve 5e of the return circuit 10c is turned off, and the flow of the working fluid from the fluid pressure pump motor 3 to the fluid pressure tank 6 is allowed.

  Thus, the current state of the load W is maintained, and the working fluid circulates between the fluid pressure pump motor 3 and the fluid pressure tank 6.

  At the start of operation of the fluid pressure control circuit 10, normally, the load is not in the load W. First, the motor 2 starts to rotationally drive the flywheel 4 and the variable displacement fluid pressure pump motor 3.

  At this time, the motor 2 only needs to have a torque necessary to rotate the variable displacement fluid pressure pump motor 3 and the flywheel 4 in an unloaded state against the associated resistance force. This is because the energy for driving the load W is supplied from the flywheel 4.

  Therefore, the capacity of the motor 2 can be remarkably reduced as compared with the case where the fluid pressure pump motor 3 is directly driven, and the circuit 10 can be reduced in size, size and cost.

  The motor 2 is ON / OFF controlled by the control means 5 so that the flywheel 4 keeps rotating within a predetermined rotational speed range by the rotational speed obtained from the rotational speed sensor 5c. At the start of operation of the circuit 10, the motor 2 continues to rotate until the rotational speed of the flywheel 4 reaches a predetermined rotational speed.

  Thus, in this load holding state, the motor 2 only holds the rotational speed of the flywheel 4 to such an extent that the working fluid is kept circulating between the fluid pressure pump motor 3 and the fluid pressure tank 6. Energy consumption can be suppressed as much as possible.

  At this time, the variable displacement fluid pressure pump motor 3 is controlled by the control means 5 so as to have a minimum tilt angle in order to reduce its driving resistance, and the amount of circulating working fluid is reduced. Furthermore, energy consumption can be reduced.

  When the operation lever 5b is operated so as to increase the load W, as shown in FIG. 2, the open / close solenoid valve 5d of the reflux circuit 10b is turned off and the reflux from the fluid pressure cylinder 1 to the fluid pressure pump motor 3 is prevented. Is done. The open / close solenoid valve 5e of the return circuit 10c is turned on, and the flow of the working fluid from the fluid pressure pump motor 3 to the fluid pressure tank 6 is blocked.

  Therefore, the working fluid is supplied from the tank 6 to the cylinder 1 by the variable displacement fluid pressure pump motor 3 driven by the flywheel 4, and the load W increases.

  At this time, the tilt angle control of the variable displacement fluid pressure pump motor 3 is performed by the control means 5 that monitors the rotational speed of the flywheel 4 and the rising speed of the load W is controlled by the discharge amount of the working fluid. Can do.

  Note that the rotational speed of the flywheel 4 decreases as the rotational energy is used, but the flywheel 4 depends on the moment of inertia and the rotational speed of the flywheel 4 according to the size of the load W, the lift height, and the lift speed. There is no problem if the determined rotational energy is set appropriately.

  When the operation lever 5b is operated to lower the load W, as shown in FIG. 3, the open / close solenoid valve 5d of the reflux circuit 10b is turned on, and the reflux from the fluid pressure cylinder 1 to the fluid pressure pump motor 3 is permitted. Is done. The open / close electromagnetic valve 5e of the return circuit 10c is also turned off, and the flow of the working fluid from the fluid pressure pump motor 3 to the fluid pressure tank 6 is permitted.

  Therefore, the working fluid discharged from the fluid cylinder 1 flows into the variable displacement fluid pressure pump motor 3 through the reflux circuit 10b and the main circuit 10a, and this variable displacement fluid pressure pump motor 3 is driven as a motor. The drive energy directly increases the rotational speed of the flywheel 4 and is stored and stored as the rotational energy of the flywheel 4.

  At this time, the load W needs to be lowered at a constant speed, not a sudden drop. For that purpose, the flow rate of the working fluid into the variable capacity fluid pressure pump motor 3 is controlled by the rotational speed of the flywheel 4. The control means 5 controls the tilt angle of the variable displacement fluid pressure pump motor 3 from the relationship with the required discharge amount.

  Therefore, according to the fluid pressure control circuit 10 with the regeneration function, it is necessary to provide a counter balance valve, a throttle valve, etc. that do not have such a regeneration function, which are necessary in a conventional fluid pressure control circuit such as a hydraulic forklift. In addition, meter-out control is possible, and the driven energy lost as heat energy by such a valve can be regenerated, that is, reused.

  Thus, according to the fluid pressure control circuit 10 with the regenerative function, the conventional fluid pressure pump motor is made to be a variable displacement type, and a flywheel is provided between the motor and the control means for performing predetermined control (this means that the space is reduced). Since the regenerative function is achieved by simply providing a), there is no multiple energy conversion as in the conventional example, so there is little energy loss, the circuit has a simple configuration, and simplification is possible. Responsiveness is also good, and the various effects described above are exhibited.

  Further, in the fluid pressure control circuit 10 with a regenerative function in operation, energy is stored in the flywheel 4, so that even in the event of an emergency and the power supply is shut off, a controller with low power consumption and an open / close electromagnetic As long as the power supply of the valve can be secured, the load W can be operated for a certain period of time, which is also effective as a disaster countermeasure.

  In addition, the combination of the open / close solenoid valves 5d and 5e is in a state in which the load W is maintained when the power is turned off.

  Further, in Patent Document 1 as a conventional example, since the pump motor is bi-directionally rotated, there is a problem that the responsiveness is not good when the pump motor is lowered immediately after being raised to recover energy. The pump motor 3 used in the function-equipped fluid pressure control circuit 10 has good responsiveness because it rotates in the same direction when operated as a pump and when operated as a motor.

  FIG. 4 is a circuit diagram showing another example of the fluid pressure control circuit with a regeneration function of the present invention. Accordingly, the same parts as those already described are denoted by the same reference numerals and redundant description is omitted.

  This fluid pressure control circuit 10A with a regeneration function uses a fluid pressure rotary actuator 1A that outputs a driving force by a fluid pressure as a torque as a fluid pressure actuator, compared to the fluid pressure control circuit 10 with a regeneration function of FIGS. The difference is that the loads W1, W2 are like an elevator provided with a counterweight.

  In other words, the fluid pressure control circuit with a regenerative function of the present invention is not limited to a forklift, but for any drive system in which energy applied to a load is returned to the circuit side as driven energy. Such a drive system is also applicable, and here, as an example, a fluid pressure control circuit 10A with a regenerative function applied to an up-and-down lifting and handling equipment such as an elevator is shown.

  This fluid pressure control circuit 10A with a regenerative function also exhibits the same effect as the fluid pressure control circuit 10 with a regenerative function of FIGS. 1 to 3 for loads W1 and W2 that rise and fall by such rotational torque.

  In addition, this invention is not limited to the said Example, The invention described in the claim and its equivalent range are included.

  In addition, a clutch for connecting / disconnecting the transmission of rotational force is provided between the variable displacement fluid pressure pump motor 3 and the flywheel 4, and the rotational load of the fluid pressure pump motor 3 is transmitted to the flywheel 4 when unnecessary. However, the loss of rotational energy of the flywheel 4 may be further reduced.

  The fluid pressure control circuit with a regenerative function of the present invention can recover the driven energy of the fluid pressure actuator, and can be used in any industrial field where simplification of the circuit and responsiveness are required.

The circuit diagram which shows an example of the fluid pressure control circuit with a regeneration function of the present invention (at the time of load maintenance) Circuit diagram when the load of the fluid pressure control circuit of FIG. Circuit diagram of the fluid pressure control circuit of FIG. The circuit diagram which shows the other example of the fluid pressure control circuit with a regeneration function of this invention

Explanation of symbols

1, 1A Fluid pressure actuator 2 Motor 3 Fluid pressure pump motor (variable capacity fluid pressure pump motor)
4 Flywheel 5 Control means 10, 10A Fluid pressure control circuit with regeneration function W, W1, W2 Load

Claims (2)

A fluid pressure control circuit with a regeneration function, comprising a fluid pressure actuator, a motor, and a fluid pressure pump motor, and regenerating the driven energy of the fluid pressure actuator,
The fluid pressure pump motor is a variable displacement fluid pressure pump motor, and a flywheel is interposed between the fluid pressure pump motor and the motor,
A fluid pressure control circuit with a regenerative function, comprising control means for controlling the tilt angle of the variable displacement fluid pressure pump motor based on the rotational speed of the flyhole and the discharge amount required for the pump motor. .   2. The fluid pressure control circuit with a regenerative function according to claim 1, wherein the motor is provided with a torque necessary for rotating the flywheel when the fluid pressure pump motor is in an unloaded state.

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