JPS62270805A - Servo valve - Google Patents

Abstract

PURPOSE:To supply pressure fluid stably without pulsation by superposing 1-3kHz electric signal on a control signal applied to a solenoid type flow control valve, and maintaining the control signal and the electromagnetic force generated on a magnet in linear relationship. CONSTITUTION:A servo valve is equipped at least with a pair of solenoid type flow control valves 10a, 10b and a control means A to put these control valves 10a, 10b in counter actions. The control means A compares actually supplied pressure p sensed by a pressure sensor 19 with a set pressure value in response to the setting signal e, and feedback control is made so that these are equal substantially. In this constitution, an oscillator circuit B is provided to superpose 1-3kHz electric signals on control signals applied to the control valves 10a, 10b according to the setting signal e. This allows maintaining of the control signal in linear relation with the electromagnetic force generated in electric magnets of the control valves 10a, 10b.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a servo valve used in a circuit to move fluid equipment as intended, and particularly to a servo valve used in a circuit for operating fluid equipment as intended. The present invention relates to a servo valve that can stably supply pressurized fluid at a desired pressure by adjusting the flow rate of the introduced and discharged pressurized fluid.

(Prior art) As a servo valve that can freely adjust the supply pressure of pressurized fluid to be supplied according to a control signal, there is an electromagnetic flow control system whose main parts are diagrammatically shown in FIG. 4(a). A set of two valves is arranged in the pressurized fluid flow path as shown in the operation explanatory diagram of FIG. There is one that allows the fluid supply pressure to be adjusted freely.

Here, these electromagnetic flow rate tIIIl [l valves attract the throttle adjustment plate 13 in the direction of the valve seat member 14 by the electromagnetic force generated in the electromagnet 11 in relation to the control signal, and cause the spherical valve body 12 to flow. The flow rate is adjusted by displacing the pressurized fluid against the energy it has, as shown in Figure 4 (
In the device shown in b), the amount of pressurized fluid introduced from an operating pressure source (not shown) through the inlet 15 is adjusted by one flow control valve 1'Oa, and the amount of pressurized fluid introduced from the outlet 16 is adjusted by one flow control valve 1'Oa. The discharge amount of the pressurized fluid to be discharged is the other flow rate i
, II and Ill are respectively adjusted by valves 10b.

Therefore, the electromagnetic flow control valves are operated in opposite directions to each other by a control means (not shown), in other words, when one control valve is opened, the other control valve is closed, so that the flow between these control valves is controlled. The supply pressure of the pressurized fluid supplied to other equipment via the supply port 17 communicated with the passage can be freely adjusted. Note that reference numeral 18 is an accommodation hole that accommodates a pressure sensor that detects the supply pressure of the pressurized fluid to be supplied.

(Problem to be Solved by the Invention) However, in general, there is a hysteresis relationship between the input signal applied to the electromagnet of the electromagnetic flow control valve and the electromagnetic force generated. The electric signal applied to the electromagnet of the control valve is expressed as 11, and the electromagnetic force generated in the electromagnet is expressed as ``Ou''.The relationship is illustrated in Figure 5 (a). The relationship between the electric signal applied to the electromagnet of the control valve and the electromagnetic force is shown in FIG. 5(b).

Therefore, as is clear from these figures, for the electric signal 1 applied to the electromagnet of each control valve, the pressure p of the pressurized fluid supplied from the supply 016 is constant, as shown in Fig. 5 (C ), there was a problem in that it fluctuated within a certain range.

This problem is usually not solved even if feedback control is performed to eliminate the deviation between the set pressure and the supply pressure.

The present invention has been made in view of such problems, and an object of the present invention is to provide a servo valve that can supply pressurized fluid in a stable state without causing fluctuations in the supply pressure of pressurized fluid. With the goal.

(Means for solving the problem) In order to achieve this object, the servo valve of the present invention is provided with an oscillation circuit that superimposes an electric signal of 1 to 3 KHz on the control signal that controls the flow control valve. .

(Function) Therefore, a frequency component of 1 to 3 KIh is superimposed on the control signal applied to each electromagnetic flow control valve. For this reason, the input signal to the electromagnet of each control valve repeatedly increases and decreases around the reference value when viewed at minute time intervals, but this causes the input signal and the electromagnetic force generated in the electromagnet to Since the hysteresis of can be eliminated, the supply pressure P has a linear relationship with the input signal that is to be the reference. In other words, the valve opening degree of each control valve can be adjusted while maintaining a linear relationship with respect to the control signal, and supply pressure can be stably supplied.

(Example) The servo valve of the present invention will be described in detail below with reference to the drawings.

FIG. 1(a) is a perspective view showing a part of the servo valve of the present invention, and parts similar to those shown in FIG. 4 are designated by the same reference numerals.

Reference numeral 15 denotes a pressurized fluid introduction port, 11 a supply port thereof, and 19 a pressure sensor housed in a housing hole.

Further, 20a and 20b are the valve bodies 1 of the electromagnetic flow control valve.
4, 21 is a lid member that is integrally fixed to the valve housing 10 and closes the opening on the throttle adjustment plate 13 side of the electromagnetic flow control valve, and 22 is a lid member that is related to a pressure sensor. 23 indicates a lead wire for applying an electric signal to the electromagnet 11 of each electromagnetic flow control valve. In addition, in this embodiment, the pressure sensor 19 is provided integrally with the valve housing 10, but
The present invention is not limited to this, and the type thereof is not limited either.

The lead wire 23 is a control means that adjusts the valve opening degrees of each control valve and operates them in opposite directions according to a setting signal e applied in relation to the magnitude of the pressure of the pressurized fluid to be supplied from the supply port 17. Connected to A. Further, the control means A compares the actual supply pressure p detected by the pressure sensor 19 with a set pressure corresponding to the setting signal e, and performs feedback control so that the supply pressure becomes substantially equal to the set pressure.

The servo valve of the present invention is provided with an oscillation circuit B that superimposes an electric signal of 1 to 3 K Ilz on the control signal applied to each electromagnetic flow control valve in accordance with the setting signal e. Note that as the oscillation circuit, a commonly available device on the market can be used, and it can also be configured integrally with the control means.

In a preferred embodiment of the servo-valve according to the invention, as shown in the block diagram, for example in FIG.
The configuration is such that an electrical signal with a frequency of 1 to 3 Kllz is superimposed on the signal applied to the signal b. Note that the symbol VO in the figure represents an initial signal applied to each electromagnetic flow j control valve, and defines the initial setting state of the control valves 10a and 10b.

Roughly speaking, in the other embodiment shown in FIG. 2, FIG. 1(b)
Unlike the embodiment shown in 1, this embodiment has a configuration in which an electrical signal of 1 to 3 KHz is superimposed on the setting signal e, and the setting signal on which this electrical signal is superimposed is inputted to the control means A.

In another embodiment shown in FIG.
The configuration is such that an electric signal of 1 to 3 Kllz is superimposed on the feedback signal fed back from the control means A to the control means A.

With this configuration, in any of the embodiments, an electric signal with a frequency of 1 to 3 KH2 can be superimposed on the control signal applied to each electromagnetic flow control valve, and the control signal The electromagnetic force can be uniquely set according to the input signal, and the problem of hysteresis between the input signal and the electromagnetic force can be solved.

By the way, the introduction pressure PO of pressurized fluid is 59X10'Pa.
, the pressure P to be supplied is 4.9X 10' to 49X 1
When the present invention is applied to a servo valve with a setting signal of 0'Pa and a setting signal of 1 to 5V, the electric signal to be superimposed has an amplitude in the range of 1/40 to 3 of the maximum setting value of the setting signal. Further, when the duty ratio is selected to be in the range of 5 to 30%, a remarkable effect is obtained, and pressure fluctuations in the pressurized fluid to be supplied can be suppressed to within 10% compared to conventional devices.

Note that the present invention is not limited to these examples,
It can also be applied to servo valves that have two or more pairs of electromagnetic flow control valves, and an electrical signal of 1 to 3 K Ilz may be applied directly to the electromagnet of each electromagnetic flow control valve, and various modifications can be made. is possible.

(Effects of the Invention) As detailed above, according to the servo valve of the present invention,
A servo valve having at least one pair of electromagnetic flow control valves has a control signal of 1 to 3 KH applied to each flow control valve.
By superimposing the electrical signals in step 2, it is possible to have a linear relationship between the control signal and the electromagnetic force generated in the electromagnet of each flow m control valve, causing pulsations in the supply pressure of the pressurized fluid. It is possible to provide a stable supply without any problems.

[Brief explanation of drawings]

FIG. 1(a) is an external perspective view showing a part of the servo valve of the present invention; FIG. 1(b) is a block diagram showing a control circuit of an embodiment of the servo valve of the present invention; 3 are block diagrams showing control circuits of other embodiments of the servo valve of the present invention, and FIGS. 4(a) and 4(b) are electromagnetic flow control circuits suitable for the servo valve of the present invention. Diagrams showing the main parts of a valve and a servo valve using the valve, FIGS. 5(a) and 5(b), are similar to FIG.
FIG. 5(C) is an explanatory diagram showing the relationship between the electric signal applied to the electromagnet of the electromagnetic flow control valve shown in FIG. 4(b) and the electromagnetic force generated; FIG. - It is an explanatory diagram showing the relationship between the electric signal applied to the valve and the supply pressure. 10a, 10b...electromagnetic flow control valve 11...
Electromagnet 12...Valve body 13...Aperture adjustment plate 14...Valve seat member 15...Introduction 0 1
6...Discharge port 11...Supply port 18...
Accommodation hole 19...pressure sensor 20a, 20b
... Accommodation hole 21 ... Lid member 22.23
... Lead wire A ... Control means B ... Oscillation circuit Figure 2 Figure 3 Figure 4 (b)

Claims (1)

[Claims] 1. comprising at least one pair of electromagnetic flow control valves and control means for operating the electromagnetic flow control valves in opposite directions,
One electromagnetic flow control valve adjusts the amount of pressurized fluid introduced,
In a servo valve that adjusts the discharge amount of the pressurized fluid introduced by the other electromagnetic flow control valve and freely adjusts the supply pressure of the pressurized fluid to be supplied according to the control signal, A servo valve that is equipped with an oscillation circuit that superimposes a 3KHz electrical signal and stably supplies pressurized fluid.