JPH10196836A - Servo valve - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To smoothly move a spool. SOLUTION: A spool 1 in which a plurality of spool bodies 1a to 1c and spool communication portions 1d and 1e are alternately formed along an axial direction is movably inserted into a cylindrical spool cover 2, and each of the spool bodies 1a, A plurality of annular grooves 3a to 3h are formed at intervals on the outer peripheral surface of the spool cover 1b, 1c, and pressurized fluid Q is supplied into the spool cover 2 from both end openings 4a, 4b of the spool cover 2 so that the spool 1 Is moved, the plurality of ports P, T formed on the outer peripheral wall of the spool cover 2 via the spool communication portions 1d, 1e.
1, T2, C1, and C2, the two ends of a spool body 1a, 1
c, a communication passage 5 is formed from the end faces of the spool bodies 1a, 1c to communicate with the outer annular grooves 3a, 3h.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a servo valve used for controlling, for example, an aircraft or a vehicle.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a conventional servo valve. This is because a plurality of large-diameter spool bodies 1a, 1b, 1c and small-diameter spool communicating portions 1d, 1e are provided.
And a spool 1 formed alternately is a cylindrical spool cover 2
The spool bodies 1a, 1
A plurality of annular grooves 3a to 3h are formed at intervals on the outer peripheral surfaces of the spool cover 2 and 1c, and openings 4a and 4b for supplying a pressure fluid Q are formed at both ends of the spool cover 2, and the spool cover 2 is formed. A supply oil port P, return ports T1 and T2, and load ports C1 and C2 are formed on the outer peripheral wall of each of these, and these load ports C1 and C2 communicate with a hydraulic cylinder (not shown) connected to a load. .

In the above configuration, as shown, when the spool 1 is in a neutral state, the supply oil port P and the return ports T1, T2 are closed by the spool bodies 1a, 1b, 1c.

Next, when the pressure of the pressure fluid Q supplied to one opening 4a becomes larger than the pressure of the pressure fluid Q supplied to the other opening 4b, and the spool 1 is moved to the right side a, the supply is stopped. The oil port P and the load port C1 communicate with each other to supply hydraulic oil to the hydraulic cylinder.
And the return port T2 communicate with each other to return the hydraulic oil from the hydraulic cylinder, and the load is moved to the right side a.

Subsequently, the pressure of the pressure fluid Q supplied to the other opening 4b is changed to the pressure fluid Q supplied to the one opening 4a.
When the spool 1 is moved to the left side b, the supply oil port P and the load port C2 communicate with each other to supply hydraulic oil to the hydraulic cylinder, and the load port C
1 communicates with the return port T1, and the hydraulic oil is returned from the hydraulic cylinder, and the load is moved to the left side b.

[0006]

In the above-mentioned conventional configuration,
An annular groove 3a formed in each spool body 1a, 1b, 1c
When the spool 1 is uniformly pressed from the entire circumference by the pressure of the pressure oil that has entered the inside of the spool 1 to 3 h, the spool 1 is concentrically held with the spool cover 2 and smoothly moved. If the spool 1 is moved to the right side a or the left side b and left as it is for several days, the pressure balance caused by the pressure oil entering each of the annular grooves 3a to 3h is disrupted, and a so-called sticking phenomenon occurs. This makes it difficult to smoothly move, and the responsiveness is reduced.

Since the outer peripheral edges 1A of the end surfaces of the spool bodies 1a, 1c are formed at right angles, the outer peripheral edges 1A of the end surfaces are formed on the inner peripheral surface of the spool cover 2 as shown by phantom lines in FIG. There is also a possibility that the smooth movement of the spool 1 may be hindered.

In view of the above problems, an object of the present invention is to provide a servo valve capable of moving a spool smoothly.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, a spool in which a plurality of large-diameter spool bodies and small-diameter spool communicating portions are alternately formed along the axial direction is provided. A plurality of annular grooves are formed movably inserted into the cylindrical spool cover, and a plurality of annular grooves are formed at intervals on the outer peripheral surface of each of the spool bodies, and pressurized fluid flows into the spool cover from both ends of the spool cover. In the servo valve, by supplying and moving the spool, a plurality of ports formed on the outer peripheral wall of the spool cover are appropriately communicated through the spool communication portion. A communication passage communicating from the end face of the main body to the outer annular groove is formed.

According to the above construction, the spool is moved to the right or left and left for several days, and then the pressure fluid is supplied into the spool cover from both ends of the spool cover to move the spool. Also, since the pressure fluid is supplied into the outer annular groove through the communication passage, and the pressure of the supplied pressure fluid uniformly presses the spool from the entire circumference to hold the spool concentrically with the spool cover, The so-called sticking phenomenon can be eliminated and the spool can be moved smoothly, and the responsiveness is excellent. In addition, since it is only necessary to form a communication passage in the spool body at both ends, the processing is easy, the production cost is hardly increased, and it is economical.

According to a second aspect of the present invention, in the first aspect of the invention, the outer peripheral edge of the end face of the spool body at both ends is formed in an arc shape. According to the above configuration, since the outer peripheral edge of the end surface of the spool body at both ends is formed in an arc shape, the outer peripheral edge of the end surface does not bite into the inner peripheral surface of the spool cover as in the related art. Further, since the outer peripheral edge of the arc-shaped end face is evenly pressed from the entire circumference by the pressure of the pressurized fluid, the spool can be held concentrically with the spool cover and can be moved more smoothly. In addition, since it is only necessary to form the outer peripheral edge of the end face of the spool body at both ends in an arc shape, machining is easy, the production cost is hardly increased, and it is economical.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a servo valve according to an embodiment of the present invention, in which spool bodies 1a, 1c at both ends of a spool 1 are provided.
A communication passage 5 communicating from the end face of the spool body 1c to the outer annular grooves 3a, 3h is formed on the outer circumferential face of each spool body 1a, 1c.
A is formed in an arc shape, and in this embodiment,
The outer peripheral edge 1B on the inner side of the inner side of the outer annular grooves 3a and 3h is also formed in an arc shape. FIG. 4 shows a configuration and an operation effect other than the above.
5 are substantially the same as those in the conventional example shown in FIG.

In the above configuration, the spool 1 is moved from the neutral position shown in FIG. 1 to the right side a or the left side b and left as it is for a few days, and then the spool cover 2 is opened from both end openings 4a and 4b of the spool cover 2. Even if the spool 1 is moved by supplying the pressure fluid Q into the
Is supplied into the outer annular grooves 3a and 3h through the communication path 5, and the pressure of the supplied pressure fluid Q uniformly presses the spool 1 from all the circumferences, so that the spool 1 is
Since the spool 1 is held concentrically, the so-called sticking phenomenon can be eliminated and the spool 1 can be moved smoothly, and the responsiveness is excellent.

Further, since the outer peripheral edges 1A of the end surfaces of the spool bodies 1a, 1c are formed in an arc shape, the outer peripheral edges 1A of the end surfaces do not bite into the inner peripheral surface of the spool cover 2 as in the prior art.

Further, since the outer peripheral edge 1A and the outer peripheral edge 1B formed in an arc shape are pressed uniformly from the entire circumference by the pressure of the pressure fluid Q, the spool 1
The movement can be performed more smoothly while being held concentrically.

In addition, since it is only necessary to form the communication passage 5 in the spool body 1a, 1c at both ends and to form the outer peripheral edge 1A of the end face and the outer peripheral edge 1B of the inner surface on the back side in an arc shape, the processing is easy and the production cost is low. Is hardly high and economical.

[0017]

According to the first aspect of the present invention, after the spool is left for a few days with the spool moved to the right or left, pressure fluid is supplied into the spool cover from both ends of the spool cover. Even if the spool is moved, the pressure fluid is supplied through the communication passage into the outer annular groove, and the pressure of the supplied pressure fluid uniformly presses the spool from the entire circumference, so that the spool is concentric with the spool cover. In this case, the so-called sticking phenomenon can be eliminated, and the spool can be moved smoothly, resulting in excellent responsiveness.
Moreover, since it is only necessary to form a communication passage in the spool body at both ends, processing is easy, and the production cost is hardly increased.
It is economical.

According to the second aspect of the present invention, since the outer peripheral edge of the end surface of the spool body at both ends is formed in an arc shape, the outer peripheral edge of the end surface does not bite into the inner peripheral surface of the spool cover as in the prior art. . Further, since the outer peripheral edge of the arc-shaped end face is evenly pressed from the entire circumference by the pressure of the pressurized fluid, the spool can be held concentrically with the spool cover and can be moved more smoothly. In addition, since it is only necessary to form the outer peripheral edge of the end face of the spool body at both ends in an arc shape, machining is easy, the production cost is hardly increased, and it is economical.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a servo valve according to an embodiment of the present invention.

FIG. 2 is a side view of the spool body at both ends.

FIG. 3 is an end view of the spool body at both ends.

FIG. 4 is a longitudinal sectional view showing a conventional example.

FIG. 5 is a side view of the both-end spool main body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spool 1a, 1c Both ends spool main body 1d, 1e Spool communication part 1A End outer peripheral edge of both ends spool main body 2 Spool cover 3a, 3h Outer annular groove 4a, 4b Opening 5 Communication passage P Supply oil port T1, T2 Return port C1, C2 Load port Q Pressure fluid

Claims (2)

[Claims] 1. A spool in which a plurality of large-diameter spool bodies and a small-diameter spool communication portion are alternately formed along the axial direction is movably inserted into a cylindrical spool cover, and an outer peripheral surface of each of the spool bodies. A plurality of annular grooves are formed at intervals, and a pressure fluid is supplied into the spool cover from both end openings of the spool cover to move the spool, thereby allowing the spool cover to move through the spool communication portion. A plurality of ports formed in the outer peripheral wall of the servo valve, wherein a communication passage communicating from the end face of each spool body to the outer annular groove is formed in the spool body at both ends of the spool. A servo valve. 2. The servo valve according to claim 1, wherein an outer peripheral edge of an end face of the both-end spool body is formed in an arc shape.