JPH063202B2 - Failure neutral mechanism of electro-hydraulic servo actuator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a failure neutral mechanism of an electrohydraulic servo actuator.

(Prior Art) One example of a conventional hydraulic control system is shown in FIG. 4, in which 01 is a main control valve, 02 is a main actuator, 03 bypass valve, 04 is a solenoid valve, and 05 is a main actuator. 02 piston rod 02a
Is a displacement detector that detects the displacement of the servo amplifier, 06 is a servo amplifier, 07 is a force motor, and 08 is a failure neutral mechanism.

When an electric input signal is input to the servo amplifier 06, the output from this is received and the force motor 07 operates to drive the spool 01a of the main control valve 01. Then, the pressure oil supply path to the main actuator 02 is switched and the main actuator 02 operates. The displacement of the piston rod 02a of the main actuator 02 is detected by the displacement detector 05
The detected signal is fed back to the servo amplifier 06. When the failure signal is input to the solenoid valve 04, the solenoid valve 04 occupies the position shown in the figure and discharges the pressure oil acting on the right end of the bypass valve 03 and the failure neutral mechanism 08. Then, the spool 03a of the bypass valve 03 is pushed to the right by the spring 03b to connect the right side chamber and the left side chamber of the main actuator 02 via the bypass valve 03, and at the same time, the cam 08a of the failure neutral mechanism 08 causes the spring 08b. Pushed up by piston rod 02a
It engages with the roller 02b provided on the above to return the piston rod 02a to its neutral position.

(Problems to be Solved by the Invention) In the above conventional mechanism, when the main actuator 02 becomes large for driving the control surface of an aircraft, the cam 08a and the spring 08b of the failure neutral mechanism 08 become very large,
There was a problem that it could not be put to practical use.

(Means for Solving Problems) In view of the above, the present invention downsizes the failure neutral mechanism to make it practical, and when the electric input signal system fails, automatically returns the actuator to the neutral position and incorporates the actuator. The purpose is to keep the entire hydraulic system safe, and the gist of it is
An actuator, a control valve operated by an electric input signal to control supply and discharge of hydraulic oil to the actuator, and a block for closing an oil passage from the control valve to the actuator when the electric input signal system fails. It has a valve and a spool that occupies a neutral position when the electric input signal system is normal, and only when the electric signal system fails, the spool is interlocked with the output side of the actuator through a link mechanism, and the actuator is An electro-hydraulic servo characterized by comprising a mechanical feedback valve that supplies hydraulic oil to the actuator when it is deviated from the neutral position and then returns to the neutral position to stop the supply and discharge of hydraulic oil. Actuator failure Neutral mechanism.

(Operation) In the present invention, since the above configuration is provided, the block valve opens the oil passage from the control valve to the actuator when the electric input signal system is normal, and the mechanical feedback valve is in the inoperative state, that is, its spool. Occupies the neutral position and closes the oil path to the actuator. However, when the electrical input signal system fails, the block valve closes the oil passage to prevent abnormal operation of the actuator due to the failed electrical input signal, and at the same time the mechanical feedback valve operates and its spool becomes the output side of the actuator. Interlocking linked via a link mechanism,
When the actuator is deviated from the neutral position, hydraulic oil is supplied to the actuator to restore the neutral position, and then the supply of hydraulic oil is stopped and stopped at the neutral position.

(Example) Hereinafter, the present invention will be specifically described with reference to an example shown in FIGS. 1 and 2.

In FIGS. 1 and 2, 1 is a main control valve, 2 is a main actuator, 3 is a solenoid valve for receiving a failure signal, 4 is a pair of oil passages 9 connecting the main control valve 1 and the main actuator 2,
Block valve mounted on 10; 5 mechanical feedback valve; 6 servo amplifier; 7 force motor; 8
Is a displacement detector.

In the normal state, as shown in FIG. 1, the supply pressure acts on the right end of the block valve 4 through the solenoid valve 3, and the spool 4a thereof is located on the left side against the spring 4b. The pair of oil passages 9 and 10 connecting the main actuator 2 and the main actuator 2 are open. Thus, when an electric input signal is applied to the servo amplifier 6, the force motor 7 is driven by the output from this and the spool 1a of the main control valve 1 is switched, and pressure oil is supplied to the main control valve 1 and the oil passages 9 and 10. Then, it is supplied to and discharged from the actuator 2 through the block valve 4 and the actuator 2 operates. The displacement of the piston rod 2a of the actuator 2 is detected by the displacement detector 8, and the detection signal is fed back to the servo amplifier 6. At this time, the supply pressure also acts on the right chamber 5a of the mechanical feedback valve 5 via the solenoid valve 3,
The spool 5b is pushed leftward against the spring 5c by the hydraulic pressure and occupies the position shown in the drawing, and the bypass circuits 11 and 12
Is closed. The cam 13a of the link mechanism 13 for mechanically feeding back the displacement of the spool 2a of the main actuator 2 is separated from the spool 5b of the feedback valve 5.

The state in which the electrical input signal system of the main control valve 1 fails is shown in FIG.

When a failure signal is input to the solenoid valve 3, it occupies the position shown in FIG. 2, the supply pressure is cut off, and at the same time, the pressure oil acting on the right end of the block valve 4 and the chamber 5a of the mechanical feedback valve 5 are blocked. The working pressure oil is discharged from the solenoid valve 3. Then, the spool 4a of the block valve 4 is pushed by the spring 4b to occupy the right side position,
The oil passages 9 and 10 are shut off to prevent abnormal operation of the main actuator 2 due to a faulty electric input signal. At the same time, the spool 5b of the mechanical feedback valve 5 is pushed by the spring 5c and moves leftward to come into contact with the cam 13a of the link mechanism 13. At this time, the spool of the main actuator 2 is
If 2a is not in the neutral position and is biased to the left as shown, for example, the spool of the mechanical feedback valve 5
Since 5b stops at the position corresponding to this, the hydraulic oil passes through the mechanical feedback valve 5 and enters the left side chamber of the main actuator 2 from the bypass circuit 11 and the piston rod 2a.
Is pushed to the right. Along with this, the oil in the right side chamber is discharged through the bypass circuit 12 and the mechanical feedback valve 5. When the piston rod 2a returns to the neutral position, this is transmitted to the spool 5b of the mechanical feedback valve 5 via the link mechanism 13 and the spool 5a also returns to the neutral position, closing the bypass circuits 11 and 12. Even when the spool 2a of the main actuator 2 is biased to the right side, the spool 2a returns to the neutral position and stops as in the above.

FIG. 3 shows a second embodiment of the present invention, in which, when normal, the spool 5b of the mechanical feedback valve 5 is a spring.
It is pushed by 5d and stopped at the right side position, and when there is a failure, the supply pressure is spooled via the solenoid valve 3 as shown.
The spool 5b is moved leftward against the spring 5d by acting on the chamber 5e at the right end of 5b until it abuts on the cam 13a of the link mechanism 13, as shown in FIGS. Although different from the first embodiment, the other constructional effects are similar, and corresponding members are designated by the same reference numerals. It is needless to say that a servo valve can be used as the main control valve in each of the above embodiments.

(Effects of the Invention) In the present invention, when the electric input signal system is normal, the block valve opens the oil passage from the control valve to the actuator, and the mechanical feedback valve is in a non-operating state, that is, the spool occupies the neutral position. Although the oil passage to the actuator is closed, if the electrical input signal system fails, the block valve closes the oil passage to prevent the actuator from operating abnormally due to the failed electrical input signal, and at the same time the mechanical feedback valve is activated. Then, the spool is linked to the output side of the actuator through a link mechanism, and if the actuator is biased from the neutral position, hydraulic oil is supplied to the actuator to return it to the neutral position and The oil supply can be stopped and stopped in the neutral position. Thus, even if the actuator is large, it can be returned to the neutral position by the hydraulic oil supplied thereto, so that a large output can be obtained. Therefore, since the machine is small and lightweight, it can be easily put to practical use, and when the electric input signal system fails, the actuator can be automatically returned to the neutral position.
It is possible to keep the entire system in which this actuator is incorporated safe.

[Brief description of drawings]

1 and 2 are system diagrams showing one embodiment of the present invention,
FIG. 1 shows a normal state, and FIG. 2 shows a fault state. FIG. 3 is a system diagram showing a state at the time of failure of another embodiment of the present invention. FIG. 4 is a system diagram showing a state at the time of failure of the conventional failure neutral mechanism. Actuator …… 2, control valve …… 1, block valve …… 4, mechanical feedback valve ……
5, spool …… 5b, link mechanism …… 13

Claims (1)

[Claims] 1. An actuator, a control valve which operates by an electric input signal to control supply and discharge of hydraulic oil to and from the actuator, and an oil from the control valve to the actuator when the electric input signal system fails. It has a block valve that closes the passage and a spool that occupies a neutral position when the electric input signal system is normal, and the spool is interlocked with the output side of the actuator through a link mechanism only when the electric signal system fails. When the actuator is deviated from the neutral position, it is equipped with a mechanical feedback valve for supplying hydraulic oil to the actuator to return it to the neutral position and then stopping the supply and discharge of the hydraulic oil. A neutral mechanism for failure of electro-hydraulic servo actuator.