JP3220647B2 - Hydraulic power unit device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic power unit, and more particularly to a hydraulic power unit which does not require a manual key switch, an electromagnetic contact switch, and a safety valve, which are required for a conventional power unit.

[0002]

2. Description of the Related Art Conventionally, this type of hydraulic power unit has
It was configured as shown in FIG.

FIG. 8 is a circuit diagram of a conventional device, in which 1 is a manual key switch, 2 is a push button switch for external operation, 4 is a motor, 5 is a hydraulic pump, 6 is an oil tank, and 7 is a switch. Reference numeral 8 denotes an oil discharge port (A), 9 denotes an oil discharge port (B), 10 denotes a hydraulic cylinder, 11 denotes a safety valve, 12 denotes a battery, 13 denotes a cylinder, and 14 denotes a power unit.

In such a conventional apparatus, when the operator closes the manual key switch 1 and closes the external operation push button switch 2, the electromagnetic contactor switch 3 operates and the motor 4 rotates.

[0005] The motor 4 and the hydraulic pump 5 are directly connected via a coupling (not shown), and the hydraulic pump 5 is driven to rotate. Oil tank 6 with rotation of hydraulic pump 5
Hydraulic oil is sucked into the hydraulic pump 5 and discharged from the oil discharge port boat (A) 8 (or the oil discharge port (B) 9) via the switching valve 7. The discharged hydraulic oil is sent to one oil chamber of the hydraulic cylinder 10 and reciprocates the piston 13, while the hydraulic oil removed from the other oil chamber by the piston 13 is discharged to the oil discharge port (B) 9. (Or return to the switching valve 7 via the oil discharge port (A) 8) and is returned to the oil tank 6.

When the reciprocating motion of the cylinder piston 13 is completed, the surplus hydraulic oil is returned to the oil tank 6 via the safety valve 11.

Here, the manual key switch 1 is used to prevent the motor from operating when the external push button switch 2 is erroneously pressed. This switch is required to manually turn off the motor when the circuit keeps closing.

The push button switch 2 for external operation is
This is a switch for operating the power unit at hand, and includes a switch SW for a motor and a switch for a switching valve (not shown). In a normal operation, the operator determines that the movement of the cylinder piston 13 is completed, and the external operation push button switch 2 is involved.

[0009] However, the switch SW may be closed continuously due to hard traffic, or the operator may continue to close the circuit by mistake. When the cylinder piston 13 does not operate normally due to leakage of hydraulic oil in the oil tank 6, the operator may continuously close the external operation push button switch 2.

Due to the above reasons, the cylinder piston 13
It is necessary to provide a safety valve 11 in order to prevent an excessive rise in oil pressure when the pushbutton switch 2 for external operation is kept pressed even after the forward movement (or the backward movement) is completed. If the safety valve 11 is not provided, the hydraulic system is destroyed due to an excessive increase in the hydraulic pressure, or the motor current increases, leading to a motor burnout accident and a dangerous state.

Further, the normal operating current of the motor 4 is as large as several tens to several hundreds of amps, and when this is opened and closed by a manual switch, the size of the switch becomes large. Therefore, the motor current can be opened and closed by a small manual switch. And the electromagnetic contactor switch 3 is provided. Safety valve 1
The contact current of the electromagnetic contactor switch 3 when the switch 1 operates may sometimes exceed the allowable current of the electromagnetic contactor switch 3.

[0012]

Therefore, the conventional hydraulic power unit has the following disadvantages. That is, 1. When the forward movement (or the backward movement) of the cylinder piston 13 is completed, the safety valve 11 is operated, and surplus hydraulic oil is returned to the oil tank 6 via the safety valve 11, but the safety valve 11 is operated. Occasionally, abnormal noise is generated from the safety valve and causes noise.

2. If rust or foreign matter adheres to the contact of the electromagnetic contactor switch 3 for starting the motor, the motor may not be able to operate due to poor contact conduction.

3. If the contacts of the electromagnetic contactor switch 3 are welded due to overcurrent and heat generated by long-time use, the motor 4 is in a continuous operation state and the motor is burned.

4. If the frequency of use is too high, it may cause burnout.

5. When the external operation push-button switch 2 is in a continuous closed state due to a stuck or erroneous operation, the motor 4 is in a continuous operation state, and the motor is burned.

6. If the cylinder piston 13 does not operate normally due to shortage or deterioration of the hydraulic oil in the oil tank 6, the operator causes the external operation push button switch 2 to be in a continuous closed state, resulting in motor burnout.

[7] When the cylinder piston 13 is in a state of being unable to move due to some mechanical obstacle during the movement, an overload is applied to the motor 4 and the motor burns out.

The present invention improves on this point and does not require a manual key switch, an electromagnetic contactor switch, and a safety valve, which are necessary for the conventional power unit. It is an object of the present invention to provide a hydraulic power unit that is lightweight and inexpensive to manufacture.

[0020]

SUMMARY OF THE INVENTION According to the present invention, a semiconductor is used for a switching device for opening and closing a motor current of a power unit,
The completion of the forward and backward movements of the cylinder piston is detected from the change in the discharge pressure of the hydraulic pump, and the pressure is maintained even after a predetermined time (time during which the motor does not burn out or time when the hydraulic pressure rises and the hydraulic system does not break). When the button switch is in the closed state, the state of the path of the opening / closing device is maintained, whereby the motor can be protected even if the operating push button switch is accidentally pressed.

Further, according to the present invention, even if a sufficient time is required for the forward or backward movement of the cylinder piston to be completed after the operation push-button switch is closed, there is no change in the pressure and the push-button switch can be further pressed. When the button switch is in the closed state, the opening / closing device is opened, whereby continuous operation of the motor due to shortage or deterioration of the hydraulic oil in the oil tank is eliminated, and the motor is protected.

Further, according to the present invention, a pressure control circuit is provided in the pressure detecting section, and the discharge pressure of the hydraulic pump generated when the forward or backward movement of the cylinder piston is completed is controlled so as to become a predetermined value. When the start of the pressure control is detected and the push button switch is still in the closed state even after a predetermined time, the open / close state of the opening / closing device is maintained, whereby the motor and the hydraulic system can be further protected. It is characterized by being constituted so that it becomes.

[0023]

Embodiment 1 A first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a circuit diagram showing a main part of a first embodiment of the present invention. 1, the same reference numerals as those in FIG. 8 denote the same components as those in FIG.

A driver seat switch 16 for preventing the motor 4 from operating even when the external operation push button switch 2 is accidentally pressed is connected to the battery 12. The pushbutton switch 2 for external operation is connected in series with the driver seat switch 16. The pushbutton switch 2 for external operation outputs a signal "1" when the pushbutton switch 2 for external operation is in a roadway state, and the pushbutton switch 2 for external operation has a predetermined time ( A timer circuit 17 (second timer) for outputting a signal “0” after a time sufficient for the cylinder piston 13 to make a forward or backward movement is connected. Further, the external operation push button switch 2 is connected to one input terminal of the AND circuit 18 and one input terminal of the holding circuit 19, respectively. The output of the timer circuit 17 is A
The ND circuit 18 is connected to another input terminal.

The output of the AND circuit 18 is a MOS transistor 2 which is a semiconductor switch for opening and closing the motor current.
Connected to 0.

A pressure sensor 21 is connected to the discharge side of the hydraulic pump 5.

The output of the pressure sensor 21 is connected to a pressure detecting device 23, the output of the pressure detecting device 23 is connected to a timer circuit 25 (first timer), and the output of the timer circuit 25 is connected to the holding circuit. 19 is connected to the other input terminal. The output of the holding circuit 19 is the AND
It is connected to another input terminal of the circuit 18.

The battery 12 is also connected to the MOS transistor 20 via a flywheel diode 22.
Is connected.

Here, the holding circuit 19 is a timer circuit 2
5 and the output of the pushbutton switch 2 for external operation are input. When the output of the pushbutton switch 2 for external operation is "0", the circuit is reset, and the signal "1" is output. When the output of the timer circuit 25 is "0", the circuit is set, and the signal "0" is output. When both the outputs of the timer circuit 25 and the pushbutton switch 2 for external operation are "1", the circuit before the output becomes "1". The state is maintained, and a signal "0" is output when both outputs become "0" at the same time.

The flywheel diode 22
Are configured to absorb a surge voltage generated when the motor current is turned off.

The timer circuit 25 outputs a signal "1" when the output of the pressure detector 23 is "0", and outputs a signal "1" for a predetermined time (1) after the output of the pressure detector 23 becomes "1".
After 2 seconds, the signal "0" is output.

The pressure detecting device 23 is provided with a pressure sensor 2
1 to detect whether or not the discharge pressure of the hydraulic pump has reached a predetermined value. If the discharge pressure has not reached the predetermined value,
It is configured to output a signal "0" and output a signal "1" when the signal reaches a predetermined value.

The predetermined value is a pressure when the movement of the cylinder piston 13 is completed.

The motor 4 is directly connected to the hydraulic pump 5 via a coupling (not shown).
Are arranged in the hydraulic oil in the oil tank 6. The hydraulic pump 5 is connected to an oil discharge port (A) 8 through a switching valve 7.
Alternatively, the oil discharge port (B) 9 is connected, the oil discharge port (A) 8 is connected to one oil chamber formed by the piston 13, and the oil discharge port (B) 9 is connected to the piston 1.
3 is connected to the other oil chamber. Also, the oil discharge port (B) 9 (or the oil discharge port (A)
8) is returned to the oil tank 6 via the switching valve 7.

FIG. 2 is a circuit diagram of the timer circuits 17 and 25.

In FIG. 2, RI is a discharge resistor, DI is a discharge diode, RTI is a time setting resistor, CTI is a time setting capacitor, and UI is an inverter element.

The time is set at RT1 and CT1, and the product of the two is approximately the set time. The discharging diode D1 is a diode for rapidly discharging the charge of the time setting capacitor CT1 when the input changes from "1" to "0".

FIG. 3 shows a circuit diagram of the holding circuit 19.

In FIG. 3, U2 and U3 are NAND elements, U4
Is an inverter element.

FIG. 4 is a circuit diagram of the pressure detecting device 23.

In FIG. 4, U5 denotes a converter element, VI denotes a reference voltage source, and VRI denotes a current setting volume.

[0043]

[Explanation of Operation] The characteristic operation of the first embodiment of the present invention configured as described above will be described.

In the following description, it is assumed that the driver seat switch 16 is always closed.

When the external operation switch 2 is at a gateway, A
Since there is a signal “0” at one of the inputs of the ND circuit 18, A
The ND circuit 18 outputs a signal “0”, the MOS transistor 20 is turned off, and the motor 4 is stopped. In this state, since the output of the timer circuit 25 is "1", the holding circuit 19 is in the reset state and outputs "1". The timer circuit 17 also outputs "1".

When the external operation switch 2 is closed, the holding circuit 19 outputs "1" in the reset state, and all the inputs of the AND circuit 18 become "1".
The ND circuit 18 outputs “1”. Thereby, MOS
The transistor 20 becomes conductive, a current flows through the motor 4, the motor 4 and the hydraulic pump 5 rotate, and the cylinder piston 13 is driven.

When the movement of the cylinder piston 13 is completed, the load on the motor 4 increases, the discharge pressure of the hydraulic pump increases, and the pressure sensor 21 outputs a voltage proportional to the pressure.

When the pressure rises to the set pressure (predetermined value) of the pressure detecting device 23, the pressure detecting device 23 outputs "1".

The signal "1" is input to the timer circuit 25, and the signal "0" is output after a predetermined time (after 1-2 seconds).

As a result, the holding circuit 19 enters the set state and outputs a signal "0".

Since the signal "0" is input from the holding circuit 19 to the input of the AND circuit 18, the AND circuit 18 outputs the signal "0", the MOS transistor 20 is turned off, and the motor current stops flowing. , The motor 4 stops.

At the moment when the MOS transistor 20 is turned off, a surge voltage is generated from the motor 4 and the flywheel diode 22 absorbs the surge voltage.

If the surge voltage from the motor 4 is not enough to damage each element in the power unit, the flywheel diode 22 is not needed.

When the motor current stops flowing, the pressure detector 23 outputs "0" again, and the timer circuit 25 outputs "1". The input of the holding circuit 19 is “1”,
It becomes "1", the set state is maintained, and "0" is still output.

As described above, the external operation push button switch 2
This state is maintained as long as is kept closed,
The stopped state of the motor 4 is maintained. Therefore, even if the pushbutton switch 2 for external operation is continuously pressed after the movement of the cylinder piston 13 is completed due to a hard or trouble of the pushbutton switch 2 for external operation, the motor 4 is automatically stopped. There is no burning. This is one of the features of the present invention.

Here, the discharge pressure of the hydraulic pump when the motor 4 is started is higher than the pressure during normal operation. Therefore, when the motor 4 is started, the starting pressure is detected by the pressure detecting device 23 and the holding circuit 19 is operated. Is set, and the motor 4 is stopped. In order to prevent this, in the present invention, the time counted by the timer circuit 25 is set longer (for example, 1 second to 2 seconds) than the start time of the motor 4 to prevent the malfunction.

In about 1 to 2 seconds, the cylinder piston 1
After the movement of the motor 3 is completed, the motor 4 does not burn out, and the hydraulic pressure does not increase enough to destroy the hydraulic system.

When it is desired to start the motor 4 again, the external operation tree button switch 2 is opened once (the holding circuit 1).
9 is reset), and when it is closed, it is in the initial state and can be started.

Normally, hydraulic oil is supplied to the hydraulic cylinder 10
However, if the hydraulic oil in the oil tank 6 is insufficient due to leakage or the like and the hydraulic oil cannot be normally sent to the cylinder 10, the operator must keep pressing the pushbutton switch 2 for external operation. There is. In this case, since the movement of the cylinder piston is not completed and the discharge pressure of the hydraulic pump does not increase, the pressure detection device 23 keeps outputting "0".

On the other hand, the timer circuit 17 outputs a signal "0" after a predetermined time has elapsed, and the output of the AND circuit 18 becomes "0", so that the MOS transistor 20 is turned off and the motor 4 is stopped. I do. Therefore, in such an abnormal state, even if the external operation push button switch 2 is continuously pressed (closed), the timer circuit 17 continues to output “0”, so that the stopped state of the motor 4 is maintained.
Is prevented from burning. This is one of the features of the present invention.

Further, normally, the operator determines that the movement of the cylinder piston 13 is completed, and opens the external operation switch 2. However, even if the operation is not opened due to an operation error or a solid traffic of the external operation switch 2, Alternatively, even if the external operation switch 2 is kept pressed due to shortage or deterioration of the hydraulic oil in the oil tank 6, one of the above operations is automatically performed, and the motor 4 is automatically stopped. . This state is maintained while the external operation switch 2 is kept closed. This is one of the features of the present invention.

Further, during the movement of the cylinder piston 13,
Even when the motor 4 cannot move due to any mechanical damage, the above operation is performed from the change in the discharge pressure of the hydraulic pump, and the motor 4 can be protected from burning. This is one of the features of the present invention.

[0063]

Second Embodiment A second embodiment of the present invention will be described with reference to the drawings.

FIG. 5 shows a circuit diagram of a main part of the second embodiment.

In FIG. 5, the same reference numerals as those in FIGS. 1 and 8 denote the same components.

When the second embodiment is compared with the first embodiment shown in FIG. 1, a pressure control device 27 for maintaining a constant discharge pressure of a hydraulic pump is used instead of the pressure detection device 23 of the first embodiment. It is characterized in that this output is connected to an AND circuit 28.

That is, the driver switch 16 for preventing the motor 4 from operating even when the external operation push button switch 2 is erroneously pressed is connected to the battery 12. The pushbutton switch 2 for external operation is connected to the driver seat switch 16 in series. The pushbutton switch 2 for external operation outputs a signal "1" when the pushbutton switch 2 for external operation is in an open state, and a predetermined time (cylinder piston piston) after the pushbutton switch 2 for external operation is in a closed state. A timer circuit 17 for outputting a signal "0" after a sufficient time for the forward and backward movements of the motor 13;
(Second timer) is connected. Further, the external operation push button switch 2 is connected to one input terminal of the AND circuit 28 and one input terminal of the holding circuit 19, respectively. The output of the timer circuit 17 is connected to another input terminal of the AND circuit 28.

The output of the AND circuit 28 is a MOS transistor 2 which is a semiconductor switch for opening and closing the mode current.
Connected to 0. A pressure sensor is connected to the discharge side of the hydraulic pump. A pressure detecting device 23 is connected to the pressure sensor 21, and the battery 12 is connected to the MOS transistor 20 via a flywheel diode 22.

The output of the pressure sensor 21 is connected to a pressure control device 27, the output of the pressure control device 27 is connected to a timer circuit 25 (first timer), and the output of the timer circuit 25 is connected to the holding circuit. 19 is connected to the other input terminal. The output of the holding circuit 19 is the AND
The circuit 28 is connected to another input terminal. Further, the output of the pressure control device 27 is connected to another input terminal of the AND circuit 28.

Here, the holding circuit 19 includes the timer circuit 2
5 and the output of the pushbutton switch 2 for external operation are input. When the output of the pushbutton switch 2 for external operation is 0, the circuit is reset, a signal “1” is output, and the output of the timer circuit 25 is output. Is set to 0 and the signal “0”
When both outputs of the timer circuit 25 and the pushbutton switch 2 for external operation are "1", the state before the output becomes "1" is held. When both outputs simultaneously become "0", a signal is output. It is configured to output “0”.

The flywheel diode 22 is configured to absorb a surge voltage generated when the motor current intersects.

When the output of the pressure control device 27 is 0, the timer circuit 25 outputs a signal “1”.
It is configured to output a signal "0" a predetermined time (1-2 seconds) after the output of the signal 7 becomes "1".

The pressure control device 27 which is a feature of the second embodiment.
Inputs the output of the pressure sensor 21 and outputs a signal "1" to the AND circuit 28 when the input is equal to or lower than the lower limit of the predetermined value (output c in FIG. 7). , A signal “0” is output to the AND circuit 28 (output c in FIG. 7), and a signal “1” is output to the timer circuit 25 when the output of the pressure sensor 21 is above or below (pulsating) a predetermined value. It is configured to output (output d in FIG. 7), and otherwise output a signal “0” to the timer circuit 25 (output d in FIG. 7).

The motor 4 is directly connected to the hydraulic pump 5 via a coupling (not shown).
Are arranged in the hydraulic oil in the oil tank 6. The hydraulic pump 5 is connected to an oil discharge port (A) 8 through a switching valve 7.
Alternatively, the oil discharge port (B) 9 is connected, the oil discharge port (A) 8 is connected to one oil chamber formed by the piston 13, and the oil discharge port (B) 9 is connected to the piston 1.
3 is connected to the other oil chamber. Also, the oil discharge port (B) 9 (or the oil discharge port (A)
8) is returned to the oil tank 6 via the switching valve 7.

FIG. 6 is a circuit diagram of a main part of the pressure control device 27.

In the drawing, U6 is a converter element, V2 is a reference voltage source, VR2 is a pressure setting volume, D2 is a diode, R2 is a hysteresis resistor, R3 and R4 are resistors, CI is a capacitor, and U7 is an inverter element. Shown respectively. R3 and R4 are set so that R3 <R4. The time constant of CI × R4 is set to be longer than the ON / OFF cycle of the MOS transistor.

FIG. 7 shows that the discharge pressure of the hydraulic pump is controlled after the external operation push button switch 2 is closed, the motor current is turned off by the timer circuit 25, and the external operation push button switch 2 is opened. Figure 5
FIG. 3 is a signal waveform diagram showing each point indicated by a mark, the capacitor CTI voltage of the timer circuit 25 shown in FIG. 2, and the capacitor CI voltage of the pressure control device 27 shown in FIG.

[0078]

[Explanation of Operation] The characteristic operation of the second embodiment configured as described above will be described.

When the external operation switch 2 is open, A
Since there is a signal “0” at one of the inputs of the ND circuit 28, A
The ND circuit 28 outputs a signal “0”, the MOS transistor 20 is turned off, and the motor 4 is stopped.

In this state, the output (c) of the pressure control device 27 is "1" and the output (d) is "0". The timer circuit 25 outputs the signal “1” to the holding circuit 19 because the input is “0”. As a result, the holding circuit 19 enters a reset state and outputs a signal “1” to the AND circuit 28. Further, the timer circuit 17 also outputs the signal “1”. Therefore, the motor 4 is stopped.

When the operator closes the external operation switch 2, the holding circuit 19 outputs a signal "1" in the reset state, and the inputs of the AND circuit 28 all become "1". 28 outputs "1". As a result, the MOS transistor 20 becomes conductive, a current flows through the motor 4, the motor 4 and the hydraulic pump 5 rotate, and the cylinder piston 13 is driven.

When the movement of the cylinder piston 13 is completed (the piston stops in FIG. 7), the load on the motor 4 increases, the discharge pressure of the hydraulic pump increases, and the pressure sensor 21 outputs a voltage proportional to the pressure. When the motor current reaches the upper limit value of the set current of the current control device 27 (the set upper limit in FIG. 7), the output (c) of the current control device 27 becomes “0”,
The output of the AND circuit 28 becomes "0", and the MOS transistor 20 is turned off.

In this state, when the pressure starts to drop and reaches the lower limit of the set pressure of the pressure control device 27 (the set lower limit in FIG. 7), the output (c) of the pressure control device 27 becomes "1".
The output of the AND circuit 28 becomes "1". This gives M
The OS transistor 20 is turned on again.

The set pressure of the pressure control device 27 has a hysteresis when the pressure increases and when the pressure decreases. The upper limit of the hysteresis is set to a value at which the motor does not burn out and each part of the device is not damaged by an increase in hydraulic pressure, and the lower limit is set to be larger than the normal operating pressure of the cylinder piston 13.

In the second embodiment, the pressure is maintained at the constant pressure in the above-mentioned predetermined range, so that the motor 4 and the hydraulic system can be further protected. Further, the conduction / non-conduction period of the MOS transistor 20 can be set within an allowable range, and damage to the semiconductor switch can be prevented.

On the other hand, since the pressure fluctuates above and below the set value of the pressure control device 27, the output (d) of the pressure control device 27 becomes "1", and this signal "1" is inputted to the timer circuit 25. The timer circuit 25 outputs a signal “0” to the holding circuit 19 after a predetermined time (after 1 to 2 seconds).

The holding circuit 19 enters a set state according to an input condition, and outputs a signal “0” to the AND circuit 28.

Since signal "0" is input to the input of AND circuit 28, AND circuit 28 outputs signal "0" and M
The OS transistor 20 is turned off, the motor current stops flowing, the motor 4 stops, and the discharge pressure of the hydraulic pump decreases.

When the pressure decreases, the output (d) of the pressure control device 27 outputs a signal “0” again, and the timer circuit 25
Outputs a signal "1". The input signals to the holding circuit 19 are “1” and “1”, but the set state is held,
The holding circuit 19 keeps outputting “0”.

Therefore, as long as the external operation push button switch 2 is kept closed, this state is maintained, so that the motor 4 maintains the stopped state.

When it is desired to start the motor 4 again, the pushbutton switch 2 for external operation is once set to the route (the holding circuit 1).
9 is reset), and the circuit closes to the initial state and can be started.

[0092]

As described above, according to the present invention, a semiconductor is used for an opening / closing device for opening / closing a current of a motor for driving a hydraulic pump, and the motor is driven by a command from an operation push button switch. The completion of the forward or backward movement of the driven cylinder piston is detected from a change in the discharge pressure of the hydraulic pump, and the pushbutton switch is still closed after a predetermined time after the predetermined pressure is exceeded. The present invention is characterized in that the semiconductor switch is made emergency through a holding circuit that detects the presence of the switch by a timer circuit and holds the detection of the timer circuit until the push-button switch is opened.

Further, according to the present invention, the change in the discharge pressure of the hydraulic pump can be maintained even after the operation push button switch is closed and the cylinder piston has sufficient time to complete the forward or backward movement. In addition, the timer circuit detects that the push button switch is in a closed state, and the semiconductor switch is turned off.

Further, the present invention comprises a pressure control device for turning off the semiconductor switch when the discharge pressure of the hydraulic pump is higher than a predetermined value and turning on the semiconductor switch when the discharge pressure is lower, and controlling the pressure to a predetermined value. A detection circuit for detecting the start of pressure control is provided in the control device, and the timer circuit detects that the pushbutton switch is still in a closed state even after a predetermined time has elapsed since the detection circuit detected the pressure control. The semiconductor switch is configured to be non-conductive by a holding circuit that holds the detection of the timer circuit until the push button switch is opened.

Therefore, the motor can be protected from burnout and the like even when the operation push button switch is kept pressed by mistake.

Further, continuous operation of the motor due to shortage or deterioration of the working oil in the oil tank is eliminated, and the motor can be protected.

Further, the motor and the hydraulic system can be further protected.

Further, since a safety valve is not required, generation of noise can be prevented.

Further, since the motor is started by the semiconductor switch, contact failure is eliminated, reliability can be improved, and burnout of the motor due to contact welding can be avoided.

Further, the present invention has excellent effects such as reduction of the weight and size of the device and reduction of the manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a main part of a first embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of timer circuits 17 and 25.

FIG. 3 shows a circuit configuration diagram of a holding circuit 19;

FIG. 4 is a circuit configuration diagram of the pressure detection device 23.

FIG. 5 is a circuit diagram of a main part of a second embodiment.

FIG. 6 is a circuit diagram of a main part of a pressure control device 27;

FIG. 7 is a diagram showing a state in which the discharge pressure of the hydraulic pump is controlled after the external operation push button switch 2 is closed, the motor current is darkened by the timer circuit 25, and the external operation push button switch 2 is turned off. FIG. 7 is a signal waveform diagram showing points indicated by crosses in FIG. 5, the capacitor CTI voltage of the timer circuit 25 shown in FIG. 2, and the capacitor CI voltage of the pressure control device 27 shown in FIG.

FIG. 8 is a circuit configuration diagram of a conventional device.

[Explanation of symbols]

1 manual key switch, 2 pushbutton switch for external operation, 3 electromagnetic contact switch, 4 motor, 5
Hydraulic pump, 6 oil tank, 7 switching valve, 8 oil discharge port (A), 9 oil discharge port (B), 10
Hydraulic cylinder, 11 Safety valve, 12 Battery, 13
Cylinder piston, 14 power unit, 16 switch for driver's seat, 17 timer circuit, 18 AND circuit, 19 holding circuit, 20 MOS transistor, 21
Pressure sensor, 22 flywheel diode, 23
Pressure detector, 25 timer circuit, 27 pressure controller, 28 AND circuit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-226500 (JP, A) JP-A-5-318370 (JP, A) Fully open 1986-81003 (JP, U) Really open 1983 182879 (JP, U) Jiko 62-4615 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F15B 20/00 F15B 11/00

Claims (2)

(57) [Claims] 1. A hydraulic power unit device comprising: a motor for driving a hydraulic pump; a cylinder piston driven by the hydraulic pump; and a drive power source for the motor. An opening / closing device comprising: an external operation switch for instructing an operator to open / close the opening / closing device; and a predetermined range for a discharge pressure of a hydraulic pump generated when the operation of the cylinder piston is completed. Output a non-conduction signal of the switchgear when the predetermined upper limit value or more,
When the discharge pressure is below the predetermined lower limit value of the predetermined range, the conduction signal of the switching device is output, and when the discharge pressure pulsates within the predetermined range, a detection signal for detecting that the pressure is being controlled is output. A pressure control circuit, a timer which is activated by the detection signal from the pressure control device and outputs a cylinder piston operation completion detection output after a predetermined time has been counted, and a cylinder piston operation completion detection signal from the timer. And a holding circuit for holding the switching device in a non-conductive state while the external operation switch is in a closed state. 2. A hydraulic power unit device comprising: a motor for driving a hydraulic pump; a cylinder piston driven by the hydraulic pump; and a power source for driving the motor. An opening / closing device made of a semiconductor; an external operation switch for instructing an operator to open / close the opening / closing device; and a predetermined range for a discharge pressure of a hydraulic pump generated when the operation of the cylinder piston is completed. Outputting a non-conduction signal of the switchgear when the range is equal to or more than a predetermined upper limit value,
When the discharge pressure is below the predetermined lower limit value of the predetermined range, the conduction signal of the switching device is output, and when the discharge pressure pulsates within the predetermined range, a detection signal for detecting that the pressure is being controlled is output. The pressure control circuit is activated by the detection signal from the pressure control device, outputs a cylinder piston operation completion detection output after a predetermined time is measured, and detects non-cylinder piston operation completion when a non-detection signal is input from the pressure control device. A first timer for outputting an output, and a second timer for outputting a cylinder piston operation completion detection output after measuring a time sufficient for completing the movement of the cylinder piston after the external operation switch is closed. A cylinder piston operation completion detection output or a non-cylinder piston operation completion detection output of the first timer, and an open / close state signal of the external operation switch There are input, when the switch for external operation is closed state,
A holding circuit for holding a non-conducting signal for bringing the switching device into a non-conducting state after the input of the cylinder piston operation completion detection output, a non-conducting signal from the holding circuit, and a cylinder piston operation completion detection from the second timer An output, a circuit for turning off the switchgear when any of a non-conduction signal from the pressure control circuit or a link state signal of the external operation switch is present. Hydraulic power unit equipment.