JPH0229882B2 - ENKAKUSEIGYOSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a remote control device provided with a delay circuit for delaying the timing of shutting off operating oil to a hydraulic pilot cylinder from the timing of shutting off power.

The remote control device controls, via a hydraulic pilot cylinder cooperating with a directional valve, the direction and speed of movement of a piston of a main hydraulic cylinder which drives the operated means, such as the boom of a crane.

Conventionally, in this type of remote control device, the piston position of a hydraulic pilot cylinder has been controlled by controlling the opening and closing of three electromagnetic valves. Among the three solenoid valves, the first solenoid valve is a normally closed solenoid valve that is used to introduce the operating oil supplied from the hydraulic pump, and is opened when the remote control device is energized. Also, the valve is controlled to be closed at the same time as the power supply to the remote control device is cut off. The other two second and third solenoid valves are normally open solenoid valves, and the second solenoid valve directs the operating oil supplied through the first solenoid valve to one of the hydraulic pilot cylinders. The third solenoid valve directs the operating oil supplied through the second solenoid valve to the other chamber of the hydraulic pilot cylinder or to the oil tank. The piston position of the hydraulic pilot cylinder is controlled by controlling the opening and closing of the second and third solenoid valves.

However, in the conventional remote control device as described above, when power is cut off while operating oil is being supplied to the main hydraulic cylinder via the directional control valve, the first
~The third solenoid valve operates simultaneously, and the first solenoid valve immediately closes to stop supplying operating oil to the hydraulic pilot cylinder. For this reason, the directional control valve is in a position where, together with the piston of the hydraulic pilot cylinder, the operating oil in the main hydraulic cylinder is shut off only by the force of the return spring provided in the directional control valve (hereinafter, this position is referred to as the neutral position). It will be returned to. In this case, the supply of operating oil to the hydraulic pilot cylinder has already been stopped, and due to flow path resistance of the solenoid valve, etc., the chamber on the side where the volume of the hydraulic pilot cylinder increases during movement to the neutral position becomes negative. As a result, the force of the return spring is reduced and the return speed to the neutral position becomes slow, resulting in a disadvantage that it takes time to stop the movement of the piston of the main hydraulic cylinder.

The present invention has been made in view of the above, and an object of the present invention is to provide a remote control device that can accelerate the return speed of the piston of a hydraulic pilot cylinder to the neutral position when power is cut off.

In order to eliminate the above-mentioned drawbacks and achieve the above-mentioned objects, the present invention is constructed as follows.

The remote control device of the present invention is a hydraulic pilot cylinder in which the pressure receiving area of the piston on one chamber side is set smaller than the pressure receiving area of the piston on the other side of the chamber, and which controls the piston position of the main hydraulic cylinder in cooperation with a directional control valve. One chamber of the hydraulic pilot cylinder is connected to an operating hydraulic pressure source by a first normally closed solenoid valve, and one chamber of the hydraulic pilot cylinder is connected to the other chamber of the hydraulic pilot cylinder by a second normally closed solenoid valve. The other chamber and the operating oil tank are connected by a normally closed third solenoid valve,
In a remote control device that controls the piston position of a hydraulic pilot cylinder, and the hydraulic pilot cylinder is biased to a neutral position by a return spring, the first solenoid valve is energized after a predetermined time delay after the power supply voltage is cut off. It is equipped with a delay means for shutting off the signal.

While the power supply voltage is being applied, the first solenoid valve is controlled to be open, and the piston position of the hydraulic pilot cylinder is controlled by controlling the opening/closing of the second solenoid valve and the opening/closing of the third solenoid valve. , the directional control valve is switched according to the piston position to control the piston position of the main hydraulic cylinder.

When the power supply voltage is cut off while operating oil is being supplied to the main cylinder via the directional control valve, the second solenoid valve and the third solenoid valve become de-energized and open, and the first solenoid valve becomes open. The solenoid valve becomes closed after a predetermined time delay set by the delay means. Therefore, for a predetermined period set by the delay means from the time when the power supply voltage is cut off, the operating oil flows through the first solenoid valve, the second solenoid valve, and the third solenoid valve.
will be supplied to the solenoid valve.

Therefore, the chamber side, where the volume increases, does not become negative pressure, so the force of the return spring is not reduced, and the piston is quickly returned to the neutral position by the force of the return spring.

The present invention will be explained below using examples.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a circuit diagram showing an example of a delay circuit in the embodiment shown in FIG.

This embodiment exemplifies the case of a remote control device that controls an on-vehicle crane.

1 is a hydraulic pilot cylinder. Hydraulic pilot cylinder 1 has hydraulic pilot cylinder 1.
is driven by the piston 1 _A to control the supply direction and amount of operating oil to each chamber of the main hydraulic cylinder 6.
A directional control valve 2 is provided which is controlled in accordance with the position of the piston _1A . Note that 3 is a manual lever for manually controlling the directional switching valve 2, and 4 and 5 are return springs for the directional switching valve 2.

The hydraulic pilot cylinder 1 includes an operating hydraulic pump P and a hydraulic pilot cylinder 1 (not shown).
A normally closed solenoid valve 8 connects one chamber _S1 of the hydraulic pilot cylinder with one chamber _S1 of the hydraulic pilot cylinder and the other chamber _S2 of the hydraulic pilot cylinder.
a normally closed solenoid valve 9 that connects the other chamber S2 to an operating oil tank R (not shown), a normally open solenoid valve 10 that connects the other chamber _S2 to an operating oil tank R (not shown), and a feedback valve that detects the position of the piston _1A of the hydraulic pilot cylinder 1. A potentiometer 15 is provided, and the operating oil supplied through the solenoid valve 8 is configured to be selectively guided to the chamber S ₁ and/or the chamber S ₂ by the solenoid valves 9 and 10. . Further, the operating oil from the hydraulic pump P is also supplied to the directional switching valve 2, and is configured to be selectively led to the main hydraulic cylinder 6 via the directional switching valve 2.

On the other hand, 11 is a main switch, such as a key switch, which turns on and off the output voltage of the on-vehicle storage battery 12. The voltage of the on-vehicle storage battery 12 output through the main switch 11 is supplied to a power switch 13 that supplies power voltage to the remote control device. The output voltage of power switch 13 is shown in FIG. 1 as _VDD . 14 is a potentiometer as a setting device, and a voltage V _DD is applied to the potentiometers 14 and 15. Further, the potentiometer 14 is configured such that the slider returns to the center position of the potentiometer 14 by the force of a spring when no external force is applied to the slider. Further, the voltage V _DD is supplied to the relay 26 . Note 2
_6-1 is a relay contact of the relay 26.

The output voltage of the potentiometer 14 is supplied to a voltage follower 16.
The output voltage of 5 is supplied to a voltage follower 17. The output voltages of voltage followers 16 and 17 are supplied to a differential amplifier 18 to detect the difference between the output voltages of voltage follower 16 and voltage follower 17. Also voltage follower 16
The output voltage is supplied to a neutral position detector 19 which detects that the position of the slider of the potentiometer 14 is within a predetermined range sandwiching the midpoint position.

The output voltage of the differential amplifier 18 and the output voltage of the neutral position detector 19 are controlled by selectively turning on the transistor 21 and/or 22 by the output voltage of the differential amplifier 18, and controlling the output voltage of the neutral position detector 19.
The output voltage is supplied to a logic operation circuit 20 that controls transistors 21 and 22 to be in an off state. The output voltage of the main switch 11 is connected to the emitters of the transistors 21 and 22 through the relay contact 26-.
The output of the transistor ₂₁ excites the solenoid valve 9, and the output of the transistor 22
The solenoid valve 10 is configured to be excited by the output of the solenoid valve 10. Also, the solenoid valve 8 has a relay 25 which will be described later.
The solenoid valve 8 is energized by supplying the output voltage of the main switch 11 via the relay contact _25-1 .

Reference numeral 24 denotes a delay circuit which detects the voltage V _DD and puts the relay 25 into a de-energized state after a set time delay from when the voltage V _DD is cut off, and is constructed as shown in FIG.

That is, the delay circuit 24 connects the voltage V _DD to the capacitor _24-1 applied via the diode _24-5 .
and a time constant circuit consisting of series resistors _24-2 and _24-3 connected in parallel to the capacitor _24-1 , and the output voltage of the time constant circuit is supplied to the relay 2.
It consists of a transistor _24-4 that drives the transistor 5,
Capacitor _24-1 when the voltage V _DD disappears
The relay 25 is configured to be energized for a predetermined period of time, for example, 0.5 seconds after the voltage V _DD disappears, depending on the discharge time. Note that diode _24-5 is for blocking reverse current, and diode _24-6 is for relay 2.
This is for suppressing the spike voltage generated by 5.
Further, the relay contact _25-1 is a relay contact of the relay 25.

In this embodiment configured as described above, the main switch 11 is turned on, and the power switch 1 is turned on.
3 is turned on, the voltage V _DD is supplied to the remote control device. Furthermore, the relay 26 is energized by the voltage V _DD being applied, and the relay contact _26-1 is turned on and the transistor 21 is turned on.
The voltage of the storage battery 12 is applied to the emitters 22 and 22. The voltage V _DD is also supplied to the delay circuit 24 . Since the voltage V _DD is supplied to the delay circuit 24, the capacitor _24-1 is charged, and the voltage at the terminal b of the capacitor _24-1 increases as shown in FIG. 3b. Note that FIG. 3a shows the on/off state of the power switch 13. By charging capacitor _24-1 , the voltage at terminal b is changed to resistor 2.
The voltage divided by _4-2 and _24-3 also rises, transistor _24-4 turns on, collector C of transistor _24-4 becomes approximately at ground potential, and relay 25 is excited. FIG. 3c shows the collector voltage waveform of the transistor _24-4 , and FIG. 3d shows the on/off state of the relay contact _25-1 . Since the resistance of the charging path of the capacitor _24-1 is small, the relay 25 is energized almost at the same time as the power switch 13 is turned on. By energizing the relay 25, the relay contact _25-1 is controlled to be on, and the solenoid valve 8 is energized and opened.

If no force is applied to the slider of the potentiometer 14, the potentiometer 14
The output voltage is a midpoint voltage, the neutral position detector 19 generates an output, and the logic operation circuit 20 controls the transistors 21 and 22 to be in the off state. Therefore, both electromagnetic valves 9 and 10 are in a non-energized state and are in an open state. As a result, solenoid valve 8
The operating oil supplied from the directional control valve 2 is returned to the oil tank _R via the solenoid valves 9 and 10, and the piston _1A becomes free. The position is the neutral position. Therefore, the supply of operating oil to the main hydraulic cylinder 6 is stopped, both chambers of the main hydraulic cylinder 6 are closed, and the main hydraulic cylinder 6 is closed.
Piston 6 _A does not move.

By operating the lever 3 in this state, the position of the piston _1A can be controlled.

The slider of the potentiometer 14 is moved from a position where the slider of the potentiometer 14 is within a predetermined range sandwiching the midpoint position, and the slider of the potentiometer 14 is moved.
When the output voltage of 4 is set in the direction of increasing,
[Output voltage of potentiometer 14] > [output voltage of potentiometer 15], and differential amplifier 1
8, the logic operation circuit 20 controls only the transistor 21 to be in the ON state. Therefore, the solenoid valve 9 is energized and becomes closed. On the other hand, the solenoid valve 10 is de-energized and in an open state. As a result, the operating oil supplied from the hydraulic pump P is guided to the chamber S1 side of the hydraulic pilot cylinder 1 via the solenoid valve ₈ , and the operating oil from the chamber _S2 side is guided to the oil tank R via the solenoid valve 10. As a result, the piston _1A moves to the right in FIG.

As the piston _1A moves to the right, the switching valve 2 switches the direction of the operating oil to the main hydraulic cylinder 6, and the piston _6A is driven to the right in FIG. Further, the moving speed of the piston _6A in the rightward direction is proportional to the offset position of the slider of the potentiometer 14 from the midpoint position.

As the piston 1 _A moves to the right, the output voltage of the potentiometer 15 increases, and when [output voltage of potentiometer 14] = [output voltage of potentiometer 15], the differential amplifier 18 detects this. , logic operation circuit 20 controls transistors 21 and 22 to be on. As a result, solenoid valve 9
and 10 are in the closed state, and the position of the piston _1A is in the locked state. For this reason, the piston _6A continues to move to the right at a speed corresponding to the slider position of the potentiometer 14, as described above. If the slider of the potentiometer 14 is released when the crane reaches a predetermined position due to the movement of the piston _6A , the slider of the potentiometer 14 returns to the midpoint position. When the slider of the potentiometer 14 returns to the neutral position, the neutral position detector 19 detects this, and the output of the logic operation circuit 20 controls the transistors 21 and 22 to be in the OFF state, and as described above, the piston 1 _A is returned to the neutral position. When the piston _1A returns to the neutral position, the operating oil to the main hydraulic cylinder 6 is cut off, and the position of the piston _6A is maintained at the position immediately before the piston _1A returns to the neutral position.

Conversely, by moving the slider of the potentiometer 14 from a position where the slider of the potentiometer 14 is within a predetermined range sandwiching the midpoint position, the output voltage of the potentiometer 14 is decreased. When set, [output voltage of potentiometer 14] <
[Output voltage of the potentiometer 15], and the output voltage of the differential amplifier 18 causes the logic operation circuit 20
controls only the transistor 22 to turn on.
Therefore, the solenoid valve 10 is energized and becomes closed. On the other hand, the solenoid valve 9 is de-energized and in an open state. As a result, the operating oil supplied from the hydraulic pump P is guided to the chambers S ₁ and S ₂ of the hydraulic pilot cylinder 1 via the solenoid valves 8 and 9. Pressure receiving area of piston 1 _A on chamber S ₁ side and piston 1 _A on chamber S ₂ side
The area of the pressure receiving portion is set at a ratio of 1:2, and when the operating oil is introduced into the chambers _S1 and _S2 , the piston _1A moves to the left in FIG.

As the piston _1A moves to the left, the directional control valve 2 switches the direction of the operating oil to the main hydraulic cylinder 6, and the piston _6A is driven to the left. Further, the moving speed of the piston _6A in the leftward direction is proportional to the amount of deviation of the slider of the potentiometer 14 from the midpoint position.

As the piston _1A moves to the left, the output voltage of the potentiometer 15 decreases, and the output voltage of the potentiometer 14]=[the output voltage of the potentiometer 15]
When the output voltage reaches 1, the position of the piston _1A is locked as in the case described above. As a result, the piston _6A continues to move to the left at a speed corresponding to the slider position of the potentiometer 14. piston 6
When the crane reaches a predetermined position due to the movement of _A , if the slider of the potentiometer 14 is released, the slider of the potentiometer 14 returns to the midpoint position, and the piston moves as in the previous case. The position of _6A is maintained at the position immediately before the piston _1A returns to the neutral position.

However, the main hydraulic cylinder 6
When the power switch 13 is turned off to cut off the voltage V _DD while operating oil is being supplied to the system, the relay 26 becomes de-energized at the same time as the voltage V _DD is cut off, and the relay contact _26-1 turns off. become. Therefore, the emitter voltages of transistors 21 and 22 become zero, and solenoid valves 9 and 10 become open. On the other hand, in the delay circuit 24, the electric charge of the capacitor _24-1 is discharged via the resistor _24-2 and the resistor _24-3 due to the cutoff of the voltage V _DD , and the voltage at the terminal b of the capacitor _24-1 becomes lower than that of the time constant circuit. The voltage decreases according to the constant as shown in FIG. 3b, and the transistor _24-4 turns off after the voltage V _DD is cut off as _shown in FIG. This becomes the voltage of the storage battery 12. Therefore, relay contact 25-
₁ is the third delay time T _D after the voltage V _DD is cut off.
It is in the off state as shown in Figure d. As a result, the solenoid valve 8 continues to be energized for the delay time T _D after the voltage V _DD is cut off, and the operating oil from the hydraulic pump P flows through the solenoid valve 8 to the solenoid valve 9 and the solenoid valve 9 during this period. It is supplied to the solenoid valve 10 via the electromagnetic valve 10. Therefore, the piston _1A returns to the neutral position quickly. As a result, when the voltage V _DD is cut off, the position of the piston 6 _A can be maintained at the position when the voltage V _DD is cut off.

Now, suppose that the delay circuit 2 is set up like a conventional remote control device.
4. If the relay 25 is not provided and the solenoid valve 8 is energized by the voltage V _DD , the solenoid valve 8 is de-energized and closed at the same time as the voltage V _DD is cut off; Also, solenoid valves 9 and 10
At the same time as the voltage _VDD is cut off, the piston 1A becomes de-energized and becomes open, and the force of the return springs 4 and 5 attempts to return the piston _1A to the neutral position.
However, for example, in the case where the piston 1 _A is located to the left of the neutral position in Fig. 1,
Since the electromagnetic valve 8 is in the closed state, the inside of the chamber _S1 becomes a negative pressure, which reduces the force of the return spring 5. As a result, the return speed of the piston _1A to the midpoint position becomes slow.

However, in this embodiment, the solenoid valve 8 is kept open by the delay circuit 24 during the delay time T _D from the time when the voltage V _DD is cut off, so that the chamber S ₁ side becomes negative pressure as described above. The piston _1A smoothly and quickly returns to the neutral position by the force of the return springs 4 and 5.

Further, the same effect can be obtained even if a delay timer is used in place of the delay circuit 24.

As explained above, according to the present invention, the normally closed first solenoid valve connects the operating hydraulic pressure source and one chamber of the hydraulic pilot cylinder, and the first solenoid valve connects the one chamber and the other chamber of the hydraulic pilot cylinder. Always open second
and a normally open third solenoid valve connecting the other chamber of the hydraulic pilot cylinder and the operating oil tank to control the piston position of the hydraulic pilot cylinder, and the hydraulic pilot cylinder has a return spring. In a remote control device that is energized to a neutral position by The movement speed to the neutral position is no longer slowed down, and the piston position of the main hydraulic cylinder is no longer moved when the power supply voltage is cut off.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a circuit diagram showing an example of a delay circuit in an embodiment of the present invention. FIG. 3 is an explanatory diagram for explaining the operation of the delay circuit shown in FIG. 2. 1... Hydraulic pilot cylinder, 2... Directional switching valve, 4 and 5... Return spring, 6...
...Main hydraulic cylinder, 8, 9 and 10...Solenoid valve, 11...Main switch, 13...Power switch, 24...Delay circuit, 25...Relay, 25-
₁ ... Relay contact, 1 _A ... Piston, V _DD ... Power supply voltage, P... Operating hydraulic pump, R... Operating oil tank.

Claims (1)

[Claims] 1 One chamber of a hydraulic pilot cylinder whose piston pressure receiving area on one chamber side is set smaller than the piston pressure receiving area on the other chamber side, and which controls the piston position of the main hydraulic cylinder in cooperation with the directional control valve and the operating hydraulic pressure. A normally closed first solenoid valve connects one chamber of the hydraulic pilot cylinder to the other chamber, a second normally open solenoid valve connects one chamber of the hydraulic pilot cylinder to the other chamber, and the other chamber of the hydraulic pilot cylinder and the operating oil. In a remote control device, the piston position of a hydraulic pilot cylinder is controlled by controlling a normally open third solenoid valve connected to a tank, and the hydraulic pilot cylinder is biased to a neutral position by a return spring. A remote control device comprising: a delay means for cutting off energization to the first electromagnetic valve after a predetermined time delay after the voltage is cut off.