JPS58681A - Proportinal valve - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a proportional valve, and further relates to a proportional valve for controlling a fluid path from a pressure source to at least one working boat of a hydraulic device.

Conventionally, several proportional valves for controlling fluid paths are known. The valves are used to control the flow of fluid through the volume. The piston, which moves within the bore of the nozzle, has two end faces that are each biased by a spring to hold the piston in a central position. When a control pressure is applied to one end face of the piston, the piston moves from the central position against the spring force. Both end faces of the piston receive the control pressure either directly or through a pilot valve having a control piston actuated by a weight or a proportional solenoid. Accordingly, the live piston moves in proportion to the electrical input signal.

The object of the invention is to improve the proportional control of moving a piston in both directions.

To achieve this objective, the invention proposes to move the piston by means of a single spring which acts as a compression spring in one direction of piston movement and as a pressure spring through a tension rod in the other direction. I try to keep it in the center position.

By using only one spring to actuate the piston, the movement of the piston can be completely symmetrical in both directions. On the other hand, if we use two springs that act on both end faces of the piston as in the past,
Since the spring coefficient a+compression value of each spring is different, symmetry as in the present invention cannot be obtained. Furthermore, since there is no difference in the steady operation of the two springs, that is, there is no difference in the loading speed that occurs with time, the present invention can maintain a perfect KN symmetric KN even if it operates for a long period of time. Furthermore, another advantage of the present invention is that the opposite free end of the piston is equipped with a limit switch or a displacement transducer in the middle or stroke.
It is possible to attach devices such as Kurita.

It should be noted that the lateral spring force is balanced by the gimbal suspension of the spring. This considerably reduces valve hysteresis. Also, by providing two adjacent end coils on either side of the spring, the lateral forces acting on the control piston can be reduced. That is, in the present invention, the stroke hysteresis can be reduced to about 3-4%, whereas in the conventional one with two springs, it is about
It shows a hysteresis of 8-. In this way, the present invention works to improve the accuracy of proportional control of valves.

Embodiments of the present invention will be described below based on the accompanying drawings.

The directional proportional valve of the invention consists of a pilot valve 10 with a solenoid 11, 12, a green pulp 14 with a main piston 15 and a centering spring 16.

In the illustrated neutral position, the king piston 15 is held in the central position by the centering spring 16. For example, when the solenoid 11 is energized, the control piston 18 of the pilot pulp 10 moves to the right in the drawing.

Then, fluid y! Fluid flows from P to the control pressure chamber 19 via the pilot valve IQ, the king piston 15 moves in proportion to the electrical input signal, a fluid passage with a curved cross section having forward movement characteristics is opened, and the fluid flows from the fluid source P to the control pressure chamber 19. Flows to the load via the port. On the other hand, boat B passes through the throttle section of the main piston 15 and stores boat)? I am paying my respects to.

When the solenoid 12 is energized, the control piston chamber 20 receives a corresponding control pressure and reverses the fluid path. A single spring isU acting on the main piston ISk is subjected to compressive stress regardless of the sliding direction of the raw piston 15. The spring 16 is pressed by two spring holders 21,22. These holders are attached to rods 23 that are screwed into holes formed in the live piston 15.

These spring holders are also attached to the rod 23 and are in contact with spherical stop members 25,26.

Stop #25/Ii1 is axially located by adjusting nut 21 to change or readjust the compression of spring 16.

The spring holders 21, 22 are mounted loosely on the rod 23, so that they can rotate freely within predetermined limits.

The gimbal suspension of spring 16 acts to reduce the force exerted by the spring on the main piston (perhaps the hysteresis tube of the valve), since the force exerted by the spring on the main piston acts only in the axial direction, in contrast to the two sliding directions of the piston in which the spring is pressure loaded. this is,
It functions to balance the reactions of the piston 15 in the two emotional directions. Therefore, the curves that tend to increase the friction of the piston are not affected by moments.

Between the spring holders 21, 22 of the rod 23 there is provided a base spring leaf 28 which limits the movement of the spring in both directions of the main piston 15.

[Brief explanation of the drawing]

The drawing is a sectional view of the proportional valve of the invention. 10...High lot valve, 11.12... ・
・Solenoid, 15... Main piston, 16...
・Spring, 18...1 Control piston, 19... Control pressure chamber, 20... Control piston chamber, 2
1.22... Spring holder, 23... Lot, 2
5.26...stop member, 2T...adjustment nut,
P...Fluid source.

Claims (1)

[Scope of Claims] (1) Mounted in a hole in the housing by a weiqin pin and held in a central position by a spring force, the two end faces are moved from said central position by selective application of control pressure. It has a piston device capable of moving the piston in one direction, as a compression spring in the first sliding direction of the piston device (1s) Fi, the piston device 05), and as a tension rod (t) in the opposite second sliding direction. 23) A single spring (1 m) acting as a compression spring via K is maintained in a central position flK. A proportional valve that controls the fluid path from a pressure source to at least one working boat member. (2. Valve #C described in claim 1 has died,
The spring (16) has two spring holder members (21, 22)
Each holder member is compressed into a piston! IflF
(15) Supported in the axial direction by K-connected rods
A proportional valve that is characterized by the following. (In the valve described in Patent Claim 1!!2F, the spring holder members (21, 22) are pivotally mounted to the spherical stop members (25!, 21) of the rod in the form of a K gimbal. (4) The valve KsI according to any one of claims 2 and 3 of the patent claim, in which the rod is connected between the pair of spring holder members (21, 22) #' A proportional valve, characterized in that it is attached to a CMI and has nine spacer sleeves (28). (5) In the valve according to any one of claims 1 to 4, A proportional valve characterized in that the spring member (16) has a pair of aS end coils on both Iw.