JPH0426897Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electro-hydraulic pressure regulator that can obtain an output pressure according to an input signal.

[Prior Art] Conventionally, according to Japanese Utility Model Application Publication No. 58-101213, there is a controller that outputs a current according to a command signal, and a secondary controller that is driven by the current from the controller and flows high-pressure fluid according to the amount of current. A pressure control valve main body that reduces the pressure and outputs it, and a pressure sensor that detects the output pressure as an electrical signal is provided on the pressure control valve main body, and the pressure sensor is electrically connected to a controller, An electromagnetic proportional control valve with a compensation device has been proposed, which includes a feedback circuit for controlling the amount of current applied from a controller to the pressure control valve body.

However, since the above-mentioned control valve is based on analog control, the pressure control valve body used therein is required to be a highly accurate and expensive one that can provide an output pressure proportional to the energizing current value, and the controller is analog. It must be constructed as an analog circuit that processes signals in a digital manner, and it is inevitable that the construction will be more complicated and expensive than a digital circuit.

[Problems to be Solved by the Invention] The purpose of the invention is to configure the electro-pneumatic proportional valve as one that performs digital control, thereby making it possible to obtain a product with a simple and inexpensive configuration; The purpose is to eliminate the influence of noise and obtain output pressure with high accuracy.

[Means for Solving the Problems] In order to achieve the above object, the electro-hydraulic pressure regulator of the present invention connects the supply port and the output port and closes the discharge port based on the on/off signal from the control circuit. an on-off solenoid valve that is switched between a first switching position that closes the supply port and a second switching position that connects the output port and the discharge port;
The output of the pressure sensor installed at the output port is used as a feedback signal, and the magnitude is compared with that of the input signal. If the input signal is larger, the on/off solenoid valve is switched to the first switching position, and the feedback signal is larger. The present invention is characterized in that it is configured to output an on/off signal for switching to the second switching position when the switching position is large.

[Function] In the control circuit, the magnitude of the feedback signal based on the output pressure and the input signal is compared, and an on/off signal is output based on the comparison result, and the on/off solenoid valve is switched based on it to regulate the output pressure. be done. That is, in the above control circuit,
The output of the pressure sensor installed at the output port is used as a feedback signal, and the magnitude is compared with that of the input signal. If the input signal is larger, a signal to switch the on-off solenoid valve to the first switching position is output from the feedback signal. If the second switching position is larger, a signal for switching to the second switching position is output, and the on/off solenoid valve is switched and controlled.

By repeating such a switching operation, the output pressure of the on/off solenoid valve is maintained at the set pressure set by the input signal.

[Effects of the invention] Since the electric-hydraulic pressure regulator of the present invention performs signal processing digitally, the control circuit can be configured with a simple digital signal processing circuit, and the control circuit can be controlled by the output from the control circuit. Since the electromagnetic valve used is a simple on-off type, it can be provided at low cost.

In addition, by making the solenoid valve an on-off type,
Compared to analog-controlled solenoid valves, it not only reduces the time required to set pressure and has faster response.
Since it is not affected by hysteresis, the fluid pressure can be set with high precision.

[Embodiment] FIG. 1 shows the basic configuration of an electro-hydraulic pressure regulator according to the present invention. This electro-hydraulic pressure regulator is configured to obtain an output pressure according to an input signal with high precision using an automatic control function based on feedback.It is equipped with a 3-port on-off solenoid valve, and this solenoid valve has a control function. Based on an on/off signal from the circuit, at least a first switching position where the supply port and the output port are in communication and the exhaust port is closed, and a second switching position where the supply port is closed and the output port and the exhaust port are in communication. It is configured to have two switching positions.

Further, a pressure sensor (pneumatic converter) is provided at the output port of the on/off solenoid valve, and the sensor is electrically connected to the control circuit, and the detected output pressure is configured to be sent to the control circuit as a feedback signal. ing. This control circuit compares the electric signal from the sensor with the input signal, and outputs an on/off signal to the on/off solenoid valve based on the result.

Therefore, in the electric-hydraulic pressure regulator having the above configuration, when an input signal for obtaining a certain set pressure is applied to the control circuit, the on-off solenoid valve will be turned off in the state where the feedback signal from the pressure sensor is smaller than the input signal. 1, the state is connected, and the pressure at the output port rapidly increases to near the set pressure. When the output pressure exceeds the set pressure, the feedback signal becomes larger than the input signal, and accordingly the on-off solenoid valve is switched to the second switching position, the fluid on the output port side is discharged from the discharge port, and the output pressure decreases. When the output pressure falls below the set pressure, the feedback signal becomes smaller than the input signal, and accordingly the on-off solenoid valve is switched back to the first switching position, and the output pressure rises again.

The above operation is performed at high speed as the output pressure rises and falls; for example, in the experimental example described later, it is approximately 40Hz.
The output pressure is regulated to the set pressure.

FIG. 2 shows a specific configuration example of the electric-hydraulic pressure regulator shown in FIG. , a first switching position where the movable core 3 is attracted to the fixed core 5 against the biasing force of the spring 4 when the current is not applied, and a first switching position where the movable core 3 is attracted to the fixed core 5 against the biasing force of the spring 4, and is biased toward the supply port 6 by the biasing force of the spring 4. In the first switching position, the supply valve body 8
opens the supply channel 9 to communicate with the output port 12 and the discharge valve body 10 closes the discharge channel 11 leading to the discharge port 13, and in the second switching position shown, the supply valve body 8 communicates with the supply channel 9. The discharge valve body 10 opens the discharge passage 11 to communicate with the output port 12.

In addition, in the figure, 14 indicates a pressure sensor.

Instead of the above-mentioned on-off solenoid valve, one having the structure shown in FIGS. 3A and 3B can also be used. The valve A in the same figure is constructed in a three-position type including the illustrated neutral position, and the valve B in the same figure is constructed by combining two two-port valves.

FIG. 4 shows an example of the above control circuit.
21 is a pressure sensor drive unit, 22 is a comparison unit, 23 is a solenoid valve drive unit, and the input terminal IN of the comparison unit 22 is
The input signal e ₃ applied to the pressure sensor is compared with the feedback signal e ₂ from the pressure sensor using the oven amplifier _OPC , and e ₂ >
If e ₃ , the output signal e ₄ = 0 (off signal) is output, and if e ₃ > e ₂ , the output signal e ₄ = 5 _V (on signal).
When an ON signal is output, the transistors Tr1 and Tr2 of the solenoid valve drive unit 23 are made conductive, and the solenoid 24 of the on/off solenoid valve connected to the transistor Tr2 is energized. .

Note that the oven amplifier _OP A in the pressure sensor driving section 21 constitutes a constant current supply circuit to the pressure sensor, and the oven amplifier _OP B constitutes a differential amplifier that differentially amplifies the output from the pressure sensor. The differential amplifier is configured to output a feedback signal _e2 proportional to the pressure applied to the pressure sensor, that is, the pressure at the output port.

FIG. 5 shows a system in which the on-off solenoid valve 1 in the electro-hydraulic pressure regulator shown in FIG. This is a type of electro-hydraulic pressure regulator. That is, the main valve 27 is switched by the output pressure from the pilot valve 28 to a first switching position where the supply port 29 and the output port 30 communicate with each other and the discharge port 31 is closed; It is configured to take a second switching position in which it is closed and the output port 30 and the discharge port 31 communicate with each other.

This main valve 27 connects the output port 30 to the pilot valve 2.
By communicating with the output port 12 of the main valve 8, the output pressure of the main valve 27 can be combined with the feedback signal, or the output pressure can be directly used as the feedback signal. Further, the supply pressure to the pilot valve 28 can be supplied through a branch passage 36 in the main valve 27, or can be supplied from a separate supply source in an external pilot type.

The large capacity electro-hydraulic pressure regulator shown in FIG. 5 can be constructed as shown in FIG.

The main valve 27 shown in FIG.
Almost the same as that shown in Publication No. 58-36405,
By supplying and discharging pilot fluid to and from the pilot chamber 41, the piston 42 descends and rises together with the piston rod 43, and the supply valve body 44 and the exhaust valve body 45 are alternately opened.
When the valve is lowered, the exhaust valve body 45 maintains the closed state in which the exhaust valve seat 46 is closed, and the piston rod 43 passing through the center of the exhaust valve body 45 moves downward, and the alligator portion 47 of the piston rod 43 closes the supply valve. The valve opening operation of the body 44 takes the first switching position in which the supply port 29 and the output port 30 communicate with each other and the discharge port 31 is closed, and the piston rod 4
3, the same operation is performed in the opposite direction as described above, and the supply valve body 44 closes the supply valve seat 48 to take a closed state, and the exhaust valve body 45 opens the valve at the alligator portion 47 of the piston rod 43. The output port 30 and the exhaust port 31 communicate with each other, and the supply port 29
6, the reference numeral 35 in FIG. 6 indicates a pressure sensor to which the output pressure of the main valve 27 is fed back.

In the electro-hydraulic pressure regulator with the above configuration, the pilot pressure vibrates minutely and acts on the main valve, which acts as a fluid dither on the main valve, thereby reducing nonlinear resistance such as friction on the main valve. Force is removed and activation improves properties such as hysteresis, sensitivity and responsiveness.

[Example] Figures 7A and 7B show the results of an experiment in which the pressure of a tank connected to the electro-hydraulic pressure regulator having the configuration shown in Figure 6 was regulated; ² and B are when 3.5Kgf/cm ² , and the following can be understood from these.

That is, the pilot valve is fully opened at the same time as the input signal is applied, and the pilot pressure increases. After that, when the set pressure is reached, the pilot valve repeats supply and exhaust while vibrating at approximately 40Hz, setting the output pressure of the main valve.
The pilot pressure oscillates with an amplitude of approximately 0.35 kgf/cm ² due to this influence, but the output pressure of the main valve is maintained at a constant value.

In addition, in a pilot valve, the movable iron core (valve body) vibrates at high speed to switch the flow path, but because the switching is done at high speed, the movable iron core does not completely contact or stick to the fixed iron core. Since the vibration occurs while suspended in the air, there is no decrease in durability.

FIG. 8 shows the input/output characteristics of the electro-hydraulic pressure regulator used in the above experiment, and it is confirmed that there is almost no hysteresis when the output pressure is gradually increased and decreased.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of an embodiment of the present invention, Figure 2 is a sectional view showing a specific example of the configuration, Figures 3A and B are symbol diagrams showing different examples of on/off solenoid valves, and Figure 4 is a control 5 is a circuit diagram showing one example of the circuit, FIG. 5 is a configuration diagram of a different embodiment of the present invention, FIG.
FIG. 3 is a diagram showing experimental results using the electro-hydraulic pressure regulator shown in the figure. 1...On-off solenoid valve, 6...Supply port, 1
2... Output port, 13... Exhaust port.

Claims (1)

[Scope of utility model registration request] A first switching position in which the supply port and the output port are communicated and the discharge port is closed, and a second switching position in which the supply port is closed and the output port and the discharge port are in communication based on an on/off signal from the control circuit. The above control circuit is equipped with an on/off solenoid valve that can be switched between
The on/off solenoid valve is compared in magnitude with the input signal, and when the input signal is larger, the on/off solenoid valve is switched to the first switching position, and when the feedback signal is larger, the on/off solenoid valve is switched to the second switching position. An electro-hydraulic pressure regulator configured to output an output.