JPH04337178A - Change-over valve - Google Patents

Abstract

PURPOSE:To provide a change-over valve which is more easily formed in a compact state compared with a conventional change-over valve, stabilizes a change-over state, and improves an operation sensation. CONSTITUTION:In a changing-over operation mechanism A, a spool 2 is forward and backward-movably inserted in the inner periphery of a partially cylindrical resilient holding body 4 having a notch 4a extending along the axial direction, and a peripheral groove 4b formed in the resilient holding body 4 and a protruding rigid ball 6 embedded in the shaft end part of the spool 2 are engaged with each other in each change-over position.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching valve used in hydraulic and pneumatic equipment, construction machinery, special vehicles, and the like.

0002

2. Description of the Related Art A switching valve typically has a switching mechanism for holding the spool in a predetermined switching position. FIG. 3 shows the detent mechanism, in which a radial through hole 102 is provided in the spool 101 of the switching valve.
A hard ball holder 102 having a diameter of 1.a is screwed onto the spool 101, and a pair of hard balls 103 are housed in this hard ball holder 102 with a coil spring 104 sandwiched between them. It is inserted into the cylindrical body 105 so that it can move forward and backward. Then, when the spool 101 comes to a predetermined switching position, the rigid ball 103 jumps out from the rigid ball holder 102 and falls into the circumferential groove 105a of the cylindrical body 105, and at this time, the two engage in uneven engagement and the spool 101 moves to the switching position. I try to keep it in place.

0003

However, if the switching operation mechanism has such a structure, the elastic force of the coil spring 104 becomes smaller when the switching valve is made more compact, and as a result, the spool at the switching position becomes smaller. 101 is reduced, resulting in the inconvenience of destabilizing the switching state, such as the switching position being deviated even by an unexpected slight external force. Further, when the holding force decreases, the operating force at the time of switching also decreases, resulting in a deterioration of the operating feel and the problem that it becomes difficult to grasp whether the spool 101 is set at the switching position. Furthermore, since the mechanism using the coil spring 104 has a large number of parts and is difficult to assemble, miniaturization further increases the inconvenience in manufacturing and assembling parts, leading to an increase in costs.

The present invention aims to solve these problems.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention employs the following configuration.

That is, in the switching valve according to the present invention, a spool is movably inserted into the inner circumference of a partially cylindrical elastic holding body having a notch along the axial direction, and either one of the elastic holding body and the spool is inserted. The present invention is characterized by having a switching operation mechanism configured such that a groove provided on one side and a protrusion provided on the other side are engaged with each other in a concave-convex manner at a switching position.

[0007]

[Operation] The partially cylindrical elastic holder with a notch can be expanded and contracted in the radial direction and exerts a spring action. That is, when the spool is in the switching position, the groove and the protrusion engage in a convex-concave manner, and when the spool moves from this state toward another switching position, the protrusion tries to ride up from the groove, and at that time the elastic The holding body is pushed apart. Therefore, the reaction force acts on the spool as a resistance force in the axial direction, and this becomes a switching operation force. On the other hand, when the spool approaches another switching position, the protrusion tries to fall into the groove again, and the elastic holder contracts at this time. Therefore, the retracting force acts on the spool as an axial assisting force, reducing the operating force.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

This switching valve is a three-position switching valve, and a rigid ball retainer 3 is fixed to the shaft end of a spool 2 extending outward from the body end surface 1, and the outer periphery of the rigid ball retainer 3 is covered. By attaching the cap 5 having the elastic holder 4 to the body end face 1 in this manner, the switching operation mechanism A is constructed. Specifically, the hard ball retainer 3 has a pair of hard ball holding holes 3a formed on its outer periphery at opposing positions sandwiching the axis, and the head is partially exposed in these hard ball holding holes 3a. The rigid ball 6 is integrally buried in a state where These hard balls 6
serves as the protrusion of the present invention. On the other hand, cap 5
The elastic retainer 4 is housed in the inner periphery, and the elastic retainer 4 has a partially cylindrical shape with a notch 4a along the axial direction, as shown in FIG. By expanding and contracting, it can act as a spring. This elastic holder 4 is provided with a circumferential groove 4b along the spherical surface of the hard ball 6, corresponding to the position where the hard ball 6 is disposed at each switching position of the spool 2. Then, when the spool 2 moves back and forth and the rigid ball holder 3 is displaced relative to the elastic holder 4, the rigid balls 6 and the circumferential groove 4b engage with each other at each switching position, and the spool 2 is moved to each switching position. I try to keep it that way.

Next, the operation at the time of switching will be explained. First, when the spool 2 is at a predetermined switching position, the circumferential groove 4b and the rigid ball 6 are engaged in a concave-convex manner. Then, when the spool 2 is moved from this state toward another switching position, the rigid ball 6 tries to climb up from the circumferential groove 4b, and at this time the elastic holder 4 is pushed apart. Therefore, the reaction force acts on the spool 2 as a resistance force in the axial direction, and this becomes a switching operation force. After the hard ball 6 rides on the circumference 4b groove,
The rigid ball holder 3 becomes movable along the inner periphery of the elastic holder 4 with a relatively small operating force. Next, when the spool 2 approaches another switching position, the rigid ball 6 tries to fall into the circumferential groove 4b again, and at this time, the elastic holder 4
is contracted. Therefore, the retracting force acts on the spool 2 as an axial assisting force, reducing the operating force.

In this way, the switching valve having this switching operation mechanism A can easily set the spool 2 to a specific switching position, and once the spool 2 is set to the switching position, It becomes impossible to displace from the switching position unless an operating force of . Moreover, when the switching operation mechanism A has the above-described structure, the partially cylindrical elastic holding body 4 exerts a spring action, so that the spool 2 is held in the switching position with a much stronger spring force than a conventional coil spring. You can leave it there. Therefore, even if the switching valve is made compact, the switching state can be stabilized, and the operating feeling can be improved by requiring a constant operating force at the time of switching. In addition, since it is mechanically simpler than the conventional one, it is easy to manufacture and assemble parts even if it is made compact, and it has excellent cost performance.

It should be noted that the present invention is not limited to the above embodiments. For example, the protrusion may be provided integrally with the spool from the beginning. Moreover, the shape of the protrusion may be a protrusion along the circumferential direction, and the shape of the groove may be a spherical surface. Furthermore, a structure may be adopted in which the protrusion is provided on the elastic holder side and the groove is provided on the spool side.

[0013]

As explained above, in the switching valve according to the present invention, the partially cylindrical elastic holding body exerts a spring action in the switching operation mechanism. For this reason, the spool can be held in the switching position with a much stronger spring force than conventional coil springs.As a result, even if the switching valve is made more compact, the switching state can be stabilized, and the operating feeling during switching can be improved. It becomes possible to improve. In addition, since the switching operation mechanism is mechanically simpler than the conventional one, it is easy to manufacture and assemble parts even if it is made compact, and excellent cost performance can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention.

FIG. 2 is a perspective view showing the elastic holding body of the same embodiment.

FIG. 3 is a sectional view corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

A...Switching operation mechanism 2...Spool 4...Elastic holding body 4a...notch 4b...Circumferential groove 6...Protrusion (rigid sphere)

Claims (1)

[Claims] Claim 1: A spool is movably inserted into the inner periphery of a partially cylindrical elastic holding body having a notch along the axial direction, and a groove provided in one of the elastic holding body and the spool and a groove provided in the other. 1. A switching valve comprising a switching operation mechanism configured such that a protrusion and a protrusion engage with each other in a concave and convex manner at a switching position.