JP2000110961A - Fluid pressure actuator control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid pressure actuator control device which is capable of pressure control with no use of any differential pressure sensor, small, light and excellently reliable. SOLUTION: A fluid pressure actuator 10 is equipped with a valve element 31 interposed between the actuator 10 and a fluid source 20 and a valve element driving means 34 having movable part 32 coupled with the valve element 31 consolidatedly and a solenoid drive part 33 for it 32 and controls the supply/ exhaust pressure of a working fluid from the fluid source 20 to fluid chambers 13a and 13b in the actuator 10 in compliance with the displacement of the valve element 31, and when the working fluid is supplied to any of the chambers 13a and 13b with displacement of the valve element 31, the supplied pressure is received in the direction against the valve element displacement with respect to the valve element 31 while the fluid pressure in the exhaust side fluid chamber is received in the direction the same as the valve element displacement so that the differential pressure between the chambers is fed back to the valve element 31 at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for controlling the output load of a hydraulic actuator by controlling the supply / discharge pressure of a working fluid between a hydraulic actuator and a fluid supply source, and more particularly to a control device for a direct drive type valve. The present invention relates to a suitable control device for a hydraulic actuator output load.

[0002]

2. Description of the Related Art In a hydraulic actuator such as a hydraulic cylinder or a hydraulic motor, an output portion such as a piston rod or a rotor is displaced (directly or rotationally) in accordance with a pressure difference between a fluid chamber on one side and a fluid chamber on the other side. However, as a direct acting device for controlling the operation of such an actuator, a predetermined flow rate of hydraulic oil is supplied from a pressure oil supply source to a fluid chamber on one side of the actuator, and the other side is supplied. The operation of discharging the hydraulic oil from the fluid chamber to the reservoir side or restricting (blocking) the flow of the hydraulic oil into and out of both fluid chambers is repeated.

[0003] Some of the spring-balanced or moving coil type electro-hydraulic servo valves can control the pressure. However, the number of parts is large, the cost is high, and the large number of parts causes problems in reliability. It is easy to occur and the internal flow rate is large, so that the consumption flow rate is large.

Therefore, in applications requiring a high degree of reliability, such as an aircraft flight control system, a spool valve connected to a hydraulic oil supply / discharge port of an actuator is directly turned on / off by a solenoid. Electromagnetic proportional control systems are frequently used.

[0005]

However, in the above-described conventional control device for a fluid pressure actuator, since it is configured as a valve unit of a direct drive flow control type, there is a case where pressure control is performed. In addition, it is necessary to perform feedback control using a differential pressure sensor, which increases the cost as a whole, increases the weight and size of the entire actuator including the valve unit, and also complicates the control system. There was a problem.

SUMMARY OF THE INVENTION The present invention provides a small, lightweight, and highly reliable fluid pressure actuator control device capable of controlling pressure without using a differential pressure sensor.

[0007]

As a means for solving the above-mentioned problem, the present invention provides a method for controlling a fluid supply between a fluid pressure actuator for displacing an output portion in accordance with a pressure difference between first and second fluid chambers and a fluid supply source. And a valve body driving means having an electromagnetic drive section for electromagnetically driving the movable section and the movable section integrally connected to the valve body, and the fluid is provided in accordance with the displacement of the valve body. A control device for controlling supply / discharge of a working fluid from a supply source to said first and second fluid chambers, wherein the working fluid is transferred to one of said first and second fluid chambers by displacement of said valve body. Is supplied, the fluid pressure in the fluid chamber to which the working fluid is supplied is received by the valve body in a direction opposite to the displacement of the valve body, and the fluid in the fluid chamber from which the working fluid is discharged Pressure is received by the valve body in the same direction as the displacement of the valve body, And a differential pressure between the second fluid chamber, characterized in that so as to constantly fed back to the valve body.

According to the present invention, the pressure difference between the first and second fluid chambers corresponding to the pressure difference between the pair of supply / discharge ports of the fluid pressure actuator exerts a thrust on the valve body in the direction of reducing the pressure difference. That is, it acts as a reaction force opposing the valve element driving thrust by the valve element driving means. Therefore, the valve element stops in a state in which the valve element driving thrust by the valve element driving means and the reaction force proportional to the differential pressure between the fluid chambers are balanced, and the valve element is simple without using a differential pressure sensor. With this configuration, it is possible to perform pressure control for controlling the output load of the actuator according to the valve element driving thrust by the valve element driving unit.

Further, when the valve element is a spool valve and pressure receiving surfaces for receiving the fluid pressures of the first and second fluid chambers are formed on both axial ends of the valve element, the number of parts increases. The required pressure-receiving surface can be easily formed on the valve element without causing the pressure-receiving surface to be formed.

[0010]

Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a view showing one embodiment of a control device for a fluid pressure actuator according to the present invention.

In FIG. 1, reference numeral 10 denotes a cylinder body 1
1 is a hydraulic actuator (fluid pressure actuator) in which a piston 12 (output unit) is slidably housed.
And second fluid chambers 13a and 13b. These first and second fluid chambers 13a, 13b are formed by a pair of supply / discharge ports 14a, 14 formed in the cylinder body 11.
Hydraulic oil can be introduced and discharged via b. Further, the hydraulic actuator 10 introduces high-pressure hydraulic oil (hereinafter, also referred to as “pressure oil”) from the hydraulic pump 21 into one of the first and second fluid chambers 13a and 13b, discharges the other from the other, and outputs a piston. 12 is displaced.
The hydraulic oil discharged from the hydraulic actuator 10 enters the reservoir 22 and is sucked into the hydraulic pump 21 from the reservoir 22. The hydraulic pump 21 and the reservoir 22 constitute a fluid supply source 20.

Hydraulic actuator 10 and fluid supply source 20
A direct drive type valve 30 is provided in the hydraulic oil supply / discharge path between the two. The direct drive type valve 30 includes a slide valve element 31 interposed between the hydraulic actuator 10 and the fluid supply source 20 and a core 3 integrally connected to the valve element 31.
2 (movable part) and the core 3 according to a command signal described later.
And a valve housing 35 for accommodating them. The fluid supply source 20 according to the displacement of the valve 31.
From the first and second fluid chambers 1 of the hydraulic actuator 10
Supply and discharge of the working fluid to and from 3a and 13b are controlled.

More specifically, the slide valve element 31 is a spool valve having a plurality of lands 31a, 31b, 31c, and 31d. Second fluid chambers 13a, 13b
Pair of left and right annular pressure receiving surfaces 3 for receiving the respective fluid pressures
1e and 31f are formed to have the same pressure receiving area. Further, when hydraulic oil is supplied to one of the first and second fluid chambers 13a and 13b due to the displacement of the valve element 31, the fluid pressure of the high-pressure side fluid chamber 13a or 13b to which the hydraulic fluid is supplied is reduced. The valve body 31 receives pressure in a direction opposite to the displacement of the valve body 31, and the fluid pressure in the low-pressure side fluid chamber 13 b or 13 a from which the hydraulic oil is discharged is directed in the same direction as the displacement of the valve body 31. The lever 31 receives pressure.

Inside the valve housing 35, an operating chamber 35a for slidably storing the slide valve element 31 is formed.
The three land portions 31a to 31d define a supply pressure chamber 36a at the center, back pressure chambers 36b and 36c on both sides thereof, and feedback pressure chambers 36d and 36e on both ends.

The valve housing 35 has a supply pressure port P for introducing pressure oil from the fluid supply source 20 into the supply pressure chamber 36a, and a return port R1 for connecting the back pressure chambers 36b and 36c to the reservoir 22, respectively. R2, control pressure ports C1, C2 connected to the pair of supply / discharge ports 14a, 14b of the hydraulic actuator 10, and a feedback pressure port F constantly communicating with the control pressure ports C1, C2.
1 and F2. And the control pressure port C1,
C2 is a position where the slide valve element 31 is in the neutral position (the position shown).
Is in the closed state (opening degree is minimum), one side thereof communicates with the supply pressure chamber 36a and the other side communicates with the back pressure chamber 36b or 36c according to the displacement direction of the slide valve body 31. Thus, the supply / discharge path of the hydraulic oil to the pair of supply / discharge ports 14a, 14b of the hydraulic actuator 10 can be switched.

The core 32 of the valve body driving means 34 comprises a shaft portion 32a and a core portion 32b coaxially connected thereto. The shaft portion 32a is connected to one end of the slide valve body 31 by, for example, a screw. , Left and right leaf springs 37a, 37b
And is supported by the valve housing 35 so as to be axially displaceable. The leaf springs 37a and 37b have a centering function of positioning the core 32 at a predetermined neutral position in the axial direction (a stop position shown in FIG. 1) and a role of stabilizing the system.

The electromagnetic drive section 33 has a magnet section 33a surrounding the core 32 and electromagnetic coils 33b disposed on both sides thereof, and can electromagnetically drive the core 32 to be displaced in the axial direction. And this core 3
The slide valve element 31 is displaced from the predetermined position by the drive of 2, and the switching of the hydraulic oil supply / discharge path by opening and closing the control pressure ports C1 and C2 described above is performed. In FIG. 1, reference numerals 41a and 41b denote leaf springs 37.
a, 37b for fixing the valve housing 35 to the valve housing 35;
b and a distance piece interposed between the leaf springs 37a and 37b for maintaining an interval, 42c is a distance piece interposed between one leaf spring 37b and an end face of the slide valve body 31, and 43 is a distance piece which is the other leaf spring 37a. It is a nut for being sandwiched and fixed between the distance piece 42a.

According to the configuration of the present embodiment as described above, when the command signal for extending the hydraulic actuator 10 is input to the valve driving means 34 which is an electric motor, the slide valve 31 shown in FIG. The middle leftward thrust acts to displace the valve element 31 in the same direction, and high-pressure hydraulic oil from the fluid supply source 20 is supplied to the first fluid chamber 13a via the supply pressure chamber 36a and the control pressure port C1. At the same time, hydraulic oil is discharged from the second fluid chamber 13b to the reservoir 22 via the control pressure port C2 and the back pressure chamber 36c. Therefore, a thrust toward the right side in the drawing is generated in the piston 12 of the hydraulic actuator 10 according to the pressure difference between the first and second fluid chambers 13a and 13b, and the piston 12 moves in the extension direction.

On the other hand, when a command signal for the direction of contracting the hydraulic actuator 10 is input to the valve body driving means 34,
A rightward thrust in FIG. 1 acts on the slide valve body 31 to displace the valve body 31 in the same direction, and high-pressure hydraulic oil from the fluid supply source 20 is supplied through the supply pressure chamber 36a and the control pressure port C2. The hydraulic fluid is supplied to the second fluid chamber 13b, and the hydraulic fluid is discharged from the first fluid chamber 13a to the reservoir 22 via the control pressure port C1 and the back pressure chamber 36b. Therefore, the first and second pistons 12 of the hydraulic actuator 10 are provided.
A thrust toward the left side in the figure is generated according to the pressure difference between the fluid chambers 13a and 13b, and the piston 12 moves in the contracting direction.

In this operating state, when the slide valve element 31 is displaced by the driving thrust from the valve element driving means 34, the pressure difference between the pair of supply / discharge ports 14a, 14b of the hydraulic actuator 10 is reduced. Equivalent first
And the differential pressure between the second fluid chambers 13a and 13b is constantly fed back from both ends of the slide valve element 31 to the valve element 31. The valve body thrust acts in proportion to the differential pressure. Further, since the differential pressure changes according to the actual load applied to the piston 12, the differential pressure corresponding to the load is used as the feedback pressure as the slide valve body 3.
1 will work.

Accordingly, the valve element 31 stops sliding when the thrust corresponding to the differential pressure (feedback pressure) and the driving thrust by the valve element driving means 34 are balanced, and the differential pressure is controlled by the valve element driving. It will increase or decrease according to the driving thrust generated by the means 34. That is,
The first and second fluids of the hydraulic actuator 10 are changed by changing the command input to the valve body driving means 34 without performing feedback control using a differential pressure sensor as in the related art. Pressure control-type control that changes the differential pressure between the chambers 13a and 13b according to the input of the command signal can be performed. As a result, the weight and size of the entire actuator including the valve unit can be reduced, and the control system can be simplified.

The slide valve element 31 is a spool valve, and annular pressure receiving surfaces 31e and 31f for receiving the fluid pressure of the first and second fluid chambers 13a and 13b are provided on both axial ends of the valve element 31. Are formed, these required pressure receiving surfaces can be easily formed on the valve body 31 without increasing the number of parts.

[0024]

According to the present invention, the differential pressure between the first and second fluid chambers of the fluid pressure actuator is used as thrust in the direction of reducing the differential pressure with respect to the valve element, that is, the valve element driving means. The valve is driven in a state in which the valve body driving thrust by the valve body driving means and the reaction force proportional to the pressure difference between the fluid chambers are balanced. With a simple configuration without stopping and using a differential pressure sensor, it is possible to perform pressure control that changes the output load of the actuator according to the valve element driving thrust. As a result, the size and weight of the entire actuator system can be reduced, and the cost can be reduced.

Further, if the valve element is a spool valve and pressure receiving surfaces for receiving the fluid pressures of the first and second fluid chambers are formed on both axial ends of the valve element, the number of parts can be reduced. The required pressure-receiving surface can be easily formed on the valve body without increasing it.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of a control device for a fluid pressure actuator according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 hydraulic actuator (fluid pressure actuator) 14a, 14b supply / discharge port 12 piston 13a first fluid chamber 13b second fluid chamber 20 fluid supply source 30 directly driven valve 31 slide valve body 31a, 31b, 31c, 31d land portion 31e, 31f Pressure receiving surface 32 Core 33 Electromagnetic drive unit 34 Valve driving means 35 Valve housing 36a Supply pressure chamber 36b Back pressure chamber 36c Back pressure chamber 36d, 36e Feedback pressure chamber C1, C2 Control pressure port F1, F2 Feedback pressure port P Supply pressure port R1, R2 Return port

Claims (2)

[Claims] A valve body interposed between a fluid pressure actuator for displacing an output portion in accordance with a pressure difference between the first and second fluid chambers and a fluid supply source; and a valve body integrally connected to the valve body. A movable part and a valve body driving means having an electromagnetic drive part for electromagnetically driving the movable part, and a working fluid from the fluid supply source to the first and second fluid chambers in accordance with displacement of the valve body A control device for controlling the supply and discharge of the fluid chamber, wherein when the working fluid is supplied to any of the first and second fluid chambers by the displacement of the valve body, A fluid pressure is received by the valve body in a direction opposite to the displacement of the valve body, and the fluid pressure of the fluid chamber from which the working fluid is discharged is increased in the same direction as the displacement of the valve body. And the differential pressure between the first and second fluid chambers is always fed back to the valve body. A controller for controlling the differential pressure between the first and second fluid chambers. 2. The valve body according to claim 1, wherein the valve body is a spool valve, and pressure receiving surfaces for receiving the fluid pressures of the first and second fluid chambers are formed on both axial ends of the valve body. Control device for fluid pressure actuator.