JPH035738Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention relates to an electromagnetic switching valve.
Specifically, the invention relates to a spool that is switchably inserted into an electromagnetic switching valve.

(Prior Art) As a conventionally used electromagnetic switching valve, there is one shown in FIG. 3, for example. That is, in the figure, 1 is a switching valve main body, and this switching valve main body 1 is provided with a hole 3 into which a steel spool 2 is fitted so as to be slidable in the axial direction. Annular grooves 5, 6, 7, 8, 9, 1 are formed on the peripheral wall of the hole 3 at predetermined intervals.
0, 11 are formed, and small diameter portions 13, 14, 15 are formed on the outer peripheral surface of the spool 2. Electromagnets 17 and 18 are attached to the end face of the switching valve body 1 where both ends of the hole 3 are open, and the electromagnets 17 and 18 are connected to the stator 19 and the core 2, respectively.
0. It is composed of an electromagnetic coil 21 and a metal push rod 22. Each push rod 22 has a core 20 at one end.
The other end is adapted to come into contact with the corresponding end surface of the spool 2. 24, 25 are fixed in the annular grooves 5, 11, and the push rods 2 of the corresponding electromagnets 17, 18
One of the plugs 24 has a liquid chamber 2 in the annular groove 5 of the hole 3.
6, and the other plug 25 has a liquid chamber 27 in the annular groove 11 part.
are defined respectively. The liquid chamber 27 communicates with the port T via a flow path 28, and the liquid chamber 27
6 communicates with the flow path 28 via the flow path 29 .
Further, the annular groove 7 is connected to the port B via the flow path 30.
In addition, the annular groove 8 communicates with the port P via the flow path 31, and the annular groove 9 communicates with the port A via the flow path 32, respectively. Further, port P is connected to a hydraulic pump (not shown), ports A and B are connected to an actuator such as a hydraulic cylinder (not shown), and port T is connected to an oil storage tank (not shown).
It is designed to circulate oil.

When, for example, the electromagnetic coil 21 of the electromagnet 17 is energized from the neutral state shown in the figure, the core 20 is attracted to the stator 19 by the generated magnetic field and rapidly moves to the left in the figure. As a result, the push rod 22 pressed by the core 20 presses the spool 2 to move it to the left, so the annular groove 7 of the hole 3 and the liquid chamber 26 communicate with each other via the small diameter part 13 of the spool 2, and the small diameter part The annular groove 9 and the annular groove 8 communicate with each other via the annular groove 14 . Therefore, the pressure oil sucked up and discharged from the oil storage tank (not shown) by the hydraulic pump is transferred from the port P to the flow path 31, the annular groove 8, the small diameter portion 14, the annular groove 9, the flow path 32, and the port. It flows into an actuator such as a hydraulic cylinder via A. At the same time, the pressure oil discharged from this actuator flows from port B to flow path 30, annular groove 7, small diameter section 13, annular groove 6, and liquid chamber 2.
6. The oil is returned to the oil storage tank via flow paths 29, 28 and port T to drive the actuator.

(Problem that the invention aims to solve) However, in such conventional electromagnetic switching valves, the spool 2 is made of metal such as steel, which makes it heavy, and the electromagnet that drives it also needs to be large. There is a problem that the power consumption increases because the spool 2 must be used, and there is also a problem that the spool 2 has a short lifespan because it is easily rusted and worn.

(Means to solve the problem) Therefore, it was considered to make the spool from ceramics, which is lightweight, does not rust, has good sliding properties, and has excellent wear resistance. It has the disadvantage of being brittle and susceptible to impact, and the impact when the push rod collides with the spool due to the energization of the electromagnetic coil causes stress to concentrate at the corner of the spool end that comes into contact with the push rod and at the corner of the step at the spool end. There is a problem that it is easy to cause damage. Therefore, it was necessary to reinforce the end of the spool that comes into contact with the push rod with metal, and one idea was to form the main body of the spool from ceramics and attach a push rod abutting part made of metal to the end of this main body. However, if the metal push rod abutting portion is directly attached to the ceramic main body, the impact upon impact of the push rod will be directly transmitted to the main body, and the above problem will not be solved.

Therefore, this problem was solved by fixing the reinforcing push rod abutment part made of metal to the end of the spool body part made of ceramics using an elastic adhesive.

(Function) In other words, it is the metal push rod contacting part that comes into direct contact with the push rod, and since the elastic adhesive cushions the impact caused by the collision with the push rod, there is a risk that the ceramic spool body will be damaged. There isn't.

(Example) This invention will be explained below based on the drawings. Figures 1 and 2 show an embodiment of the electromagnetic switching valve according to this invention. First, I will explain the configuration.
The same parts as the conventional one are given the same reference numerals, and the explanation thereof will be omitted, and only the different parts will be explained.

In the figure, 35 is a spool. This spool 3
5 is made of ceramics and has a small diameter portion 1 on the outer peripheral surface.
3, 14, and 15, and an axial protrusion 36a at both ends, and an elastic adhesive, such as a rubber-based adhesive such as silicone rubber, on the protrusion 36a, as shown in detail in FIG. adhesive 37
It consists of a metal push rod abutting portion 38 fixed by. The configuration of other parts is the same as the conventional one described above. In addition, in FIG. 1, only one end of the spool 36 in the axial direction is shown.
The other end side is omitted because it has the same structure.

Next, the effect will be explained.

When the electromagnetic coil 21 of the electromagnet 17 or 18 is energized and the core 20 is attracted to the stator 19 side, the core 20
The push rod 22 pressed by the spool 35 collides with one end surface 38a of the metal push rod abutting portion 38 of the spool 35, causing the spool 35 to slide. The main body portion 36 of the spool 35 that makes sliding contact with the wall surface of the hole 3 of the switching valve main body 35 is made of ceramics, and is lightweight, rust-free, and has good sliding properties, so that the spool 35 operates smoothly. push rod 2
The impact generated when the two collide with each other is softened by the elastic adhesive 37 and then transmitted to the main body part 36.
There is no possibility that the tip end corner part a or the corner part 36b of the step part will be damaged. The functions of the other components and the flow path of the pressure oil are the same as those of the conventional electromagnetic switching valve described above.

(Effects) As explained above, according to this invention, the spool is composed of a main body made of ceramics and a contact part of a metal push rod fixed to the end of the main body with an elastic adhesive. . Therefore, the spool main body part that makes sliding contact with the wall of the hole in the switching valve main body is lightweight, does not rust, has excellent sliding properties and wear resistance, and operates smoothly, so it has a long life. The electromagnet may also be one with low power consumption. Furthermore, the push rod collides with the metal push rod abutting portion of the spool rather than the ceramic body, and the impact generated during the collision is transferred to the elastic adhesive before being transmitted to the main body. Therefore, various effects such as eliminating the risk of damage to the corners of the end portion of the main body portion and the corner portions of the step portion can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a front sectional view of one embodiment of the electromagnetic switching valve according to this invention, Fig. 2 is an enlarged partial cross-sectional view of one end of the spool of the electromagnetic switching valve of Fig. 1, and Fig. 3 is a conventional one. FIG. 3 is a front sectional view of the electromagnetic switching valve. 17, 18... Electromagnet, 20... Core, 21...
... Electromagnetic coil, 22 ... Push rod, 35 ... Spool, 36 ... Main body part, 36a ... Projection, 37
...Adhesive, 38...Push rod contact part.

Claims (1)

[Claims for Utility Model Registration] (1) The core, which is attracted and driven by energizing the electromagnetic coil of an electromagnet, is brought into contact with the end of the spool via a push rod to move the spool, and the direction of flow of the fluid is controlled. An electromagnetic type switching valve, characterized in that the spool is composed of a main body made of ceramics and a metal push rod abutment part fixed to an end of the main body with an elastic adhesive. switching valve. (2) The electromagnetic switching valve according to claim 1, wherein the attachment portion of the push rod abutting portion to the main body portion is a protrusion protruding from an end of the main body portion.