JPS60139903A - Servo valve - Google Patents

Abstract

PURPOSE:To achieve a stabilized high-speed drive of a resonance load system by arranging a mechanical hydraulic type dynamic load damper between the servo valve and the actuator which drives the resonance load in a servo valve which converts an electric signal into a hydraulic signal. CONSTITUTION:So-called resonance load system is constructed by linking a body 203 having a large inertia with a shaft 127 which is formed as one body with a piston 112 of an actuator 110 via a spring 200 and further by linking a rigid body 202 with a cylinder 111 via a spring 201. Furthermore, a servo valve 101 which functions as a positioning control device, comprises a servo valve main body 102 and a mechanical hydraulic type dynamic load damper D arranged between the passages 107, 108 which in turn connects a pair of ports of the main body to the actuator 110. The damper D consists of an isolation piston section 210 and a circuit in series of a bypass valve 220. Thus, a stabilized high-speed drive of the resonance load is achieved and the static accuracy at rest is ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a servo valve that converts electrical signals into hydraulic signals.

A conventional example will be explained with reference to FIGS. 1 to 5. 1st
The figure is a diagram showing a schematic configuration of the valve. Code 2 in the diagram
indicates the main spool. This main spool 2 is provided so as to be able to slide inside the cylinder 3 in directions 1-11 indicated by arrows in the figure, and springs 4A and 4B tensioned from the cylinder 3 are connected to both ends. . Valve bodies 5A and 5B are formed at both ends of the spool 2, and a valve body 5C is formed at the center. On the other hand, a hydraulic pressure supply channel 6 is connected to the center of the cylinder 3, and the cylinder 3 is connected between the valve bodies 5A and 50 and between 5B and 5C on the side facing this hydraulic pressure supply channel 6.
Hydraulic load passages 7 and 8 are connected to the hydraulic load passages 7 and 8, respectively. A constant oil pressure source 9 is connected to the hydraulic pressure supply passage 6, and the hydraulic load passages 7 and 8 are connected to an actuator cylinder IIK. The above actuator 10
The piston 12 is comprised of the cylinder 1 and a piston 12 that is slidably provided within the cylinder 11 in the direction indicated by the arrow in the figure. A shaft 27 is connected to the piston 12.

A back pressure control passage 13 is provided between the constant oil pressure source 9 and both ends of the spring 4 of the cylinder 3 where the spring 4B is provided. An orifice 14 with a constant opening is inserted in the back pressure control passage 13 between the constant oil pressure source 9 and the cylinder 3 on the spring 2-4A side), - the power running oil pressure source 9 and the spring 4B side. back pressure control flow path 13 between the cylinder 3 of
An orifice 15 with a constant opening degree is inserted in the hole. And the back pressure control channel 1 on the spring 4A side of the orifice 14
The solenoid valve 17 is branch-connected to 3J/C. On the other hand, in the back pressure control flow path 13 on the spring 4B side of the orifice 15,
A solenoid valve 19 is branch-connected.

These electromagnetic valves 17 and 19 are driven by signals from a pulse width modulation drive unit (hereinafter referred to as sphere drive unit) 20, and this PWM drive unit 20 is controlled by a command signal generation unit 211C.

That is, the command signal generating section 21 outputs a command signal E'i to the PWM driving section 2o as shown in FIG. PWM
As shown in FIG. 3, the drive unit 2o transmits the command signal E at a constant period T with a duty of D=Δt/T: D'=Δ
t/, etc., and the duty is D to supply the drive signal to the electromagnetic valve 17, and the duty is D' to supply the drive signal to the electromagnetic valve 19.

Therefore, the solenoid valve 17 is turned on and off by the drive signal shown in FIG.
17, it is turned off and becomes fully closed. On the other hand, the solenoid valve 19 is turned on and off by a drive signal as shown in FIG. 317, it is on and in a fully open state. By intermittently turning on and off the electromagnetic valves 17 and 19 and controlling their fully closed and fully opened states, the amount of oil in the main spool 2 is adjusted.
The main spool 2 is completely positioned by controlling the back pressure on both ends.

Further, the command signal generating section 21 adjusts the command signal E in accordance with the amount of deviation of the signals from the displacement amount detecting section 22 which is provided on the shaft 27 and detects the amount of displacement, and the displacement amount setting section 23 which sets the amount of displacement. .

Note that a flow path 24 is connected to the cylinder 3 between the back pressure control flow path 13 and the hydraulic load flow path 7, and to the cylinder 3 between the back pressure control flow path 13 and the hydraulic load flow path 7. This channel 24 communicates with a tank 25. Also, the electromagnetic
A tank 26 is provided below 17 and 19 to accommodate the oil that flows out.

In the above configuration, when the load on actuator io is a resonant load, the actuator electrically detects the multi-load pressure by inserting an electrical filter into the displacement feedbook system, and its approximate differential pZIn is a signal proportional to i7・
The system was completely stabilized by driving the resonant load stably by using the dopa-', but since it was composed of an electric system, it had the problem of low reliability.

□ The present invention has been made based on the above points, and its purpose is to provide a valve capable of stably handling a resonant load.

□In other words, the valve according to the present invention uses a solenoid valve to selectively divert the oil flow rate 5- from a constant oil source through the □ orifice with a constant opening to the tank, thereby differentially controlling the back pressure of the main spool. In the servo valve, which has an electric/hydraulic converter that generates a differential pressure proportional to the command signal and positions the main spool, a mechanical-hydraulic damper is connected between the resonant actuator and the actuator that drives the load. , Claude Dan Lee was set up and left.

An embodiment of the present invention will be described below with reference to FIG. The symbol in the figure 'l '0 'J is sir? The valve is also indicated by the symbol 11.
``0'' indicates ``actuation = work.'' This actuator 1
10 consists of a cylinder 111 and a piston 112 that slides inside this cylinder 1"11. This piston 112KFi shaft 127 is connected to the shaft 7).
'J 2 y is connected to a large □ inertia 2θ3 via a spring 200, and the cylinder 111
The surf valve 10 is connected to the key 11 body 2δ2 via the Sderin f'201 to position the resonant load system.
1 has the following configuration. In other words, between the passages 107 and 10B connecting the pair of boats of the valve body 102 and the actuator 110, there is an ice ray piston portion 21σ and a pinot (
A mechanical-hydraulic dynamic load damper consisting of a series circuit of a gas valve 22θ is inserted. The isolation piston portion 210 is a cylinder 211. This cylinder 2
11, and isolation piston springs 213 and 214 tensioned from the cylinder 211 at both ends of the isolation piston 212. Further, the pi-nine valve 220 is connected to the cylinder 221. This cylinder 22
Bypass valve spool 222° sliding inside 1 This pie A
? A metering orifice 223 formed in the spool spool 222 and communicating with both sides of the pi/4' valve spool 2220
and metering piston springs 224 and 225 stretched across both ends of the bypass valve spool 222.

Between the cylinder 221 and the passage 107 is a passage 22.
A passage 227 is disposed between the cylinder 221 and the passage 108.

Further, in the figure, reference numeral 12θ indicates a position detector, 121 indicates a serve amplifier, 122 indicates a PWM drive section, and 123 indicates a position setting device.

In the above configuration, the displacement of the pin-four valve spool 222 is set to Xs, and the pressures on the passages 107 and 108 sides are set to pc4. If pc2 is the displacement X.

and the load pressure (Pc1-P, ) have a relationship as shown in the following equation (I).

Diameter of gu orifice 223, metering piston spring 22
Spring constant of 4,225, pressure receiving area of bypass valve spool 222, ice rayon piston spring 213.214
It is determined from the spring constant of and the pressure receiving area of the isolation piston 212. In addition, the time constant τD of the differential is the diameter of the metering orifice 223, the metering piston spring 22
4.225 spring constant, Pi/IP spool 222
Pressure receiving area, isolation, piston.

It is determined from the spring constants of the pins 21.9 and 274 and the pressure receiving area of the nine range thin piston 21'2.

As is clear from the above formula (■), is it based on this example? Dynamic Load Dan Z4 has characteristics as a so-called bandpass filter, and by matching its band frequency with the natural frequency of the entire system, it is proportional to the load pressure (PcI Pc2) in the vicinity of the natural frequency of the entire system. The displacement X8 of the pi-gus valve susol 222 and the load pressure (
Pi/4' proportional to the product of the square roots of PCI Pc2)
A gas flow rate Q8 is generated. That is, as shown by the arrow in the figure, from the passage 1079- side to the passage 226. The binoculars are made to flow through the cylinder 221 and the passage 227 to the passage 10g side.

Or, conversely, it is bypassed from the passage 108 side to the shift 0 side. The damping effect in the actuator 110 can be ensured by this no-pass flow rate QB. , In addition, in the low frequency range, r-in decreases significantly, and when stationary, the bypass valve spool 222 is positioned at the neutral point, causing Nonoi A? The flow rate and amount Q are 0. This makes it possible to ensure the rigidity of the entire system.

□ Note that the number of band layers i is the same as above. diameter of the metering orifice 223, the spring constant of the metering piston springs 224, 225, and the path valve spool 22.
2 pressure receiving area, ice rayon piston spring 213.
It can be appropriately selected by combining the spring constant of 214 and the pressure receiving area of the ice rayon piston 212.

Therefore, the natural frequency of the entire system including the resonant load is 10− If given, an optimal design is possible.

As detailed above, the valve according to the present invention uses a solenoid valve to selectively divert the flow of oil that passes through an orifice with a constant opening from a constant oil pressure source to a tank, thereby differentially controlling the back pressure of the main spool. A mechanical-hydraulic dynamic load damper is installed between the valve and the actuator that moves the resonant load. This is a configuration in which aJI is provided.

Therefore, mechanical-hydraulic dynamic load damping/fK
It is possible to drive the resonant load more stably and at high speed, and the bypass flow rate can be set to 0 when it is stationary, ensuring rigidity and thereby effectively ensuring static accuracy. It can greatly improve your sexuality.

[Brief explanation of drawings]

Figures 1 to 5 are diagrams showing conventional examples, and Figure 1 is a diagram showing a conventional example. A schematic configuration diagram showing the configuration of the valve, Figure 2 is a diagram showing the command signal output from the command signal generator, and Figure 3 is the P917M.
Figures 4 and 5 are diagrams showing command signals converted by the drive unit; Figures 4 and 5 are diagrams showing drive signals supplied to the solenoid valve;
The figure shows an embodiment of the present invention. It is a schematic block diagram of a valve. 101...Sir? Ben, 102...Sir? Valve body, 1
DESCRIPTION OF SYMBOLS 10... Actuator, 210... Eye relation piston part, 220... Pinoyasu valve. Applicant Sub-Agent Patent Attorney Takehiko Suzue Figure 2 4. Figure 4 □ Time, Det' Figure 5 Figure 6 03 112/-1□7 00 201 , \202- , i 224 212 213 . 225 211 221 Garden■” □Time

Claims (1)

[Claims] The flow of oil passing through an orifice with a constant opening from a constant oil pressure source is selectively diverted to the tank by a solenoid valve, and the back pressure of the main spool is differentially changed, generating a total differential pressure proportional to the command signal. A servo valve, characterized in that the servo valve has an electric/hydraulic converter for positioning the main spool, and a mechanical-hydraulic dynamic load damper is provided between the valve and an actuator for driving a resonant load.