JPH0359309B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a spool type electromagnetic directional control valve.

[Conventional technology]

Many return spring structures for this type of spool-type electromagnetic directional control valve are conventionally known.

This conventional structure is configured such that a spool within the valve body is held in position by a return spring, and the spool can be switched and slid by a plunger of a solenoid.

By the way, not only this type of electromagnetic directional control valve but also spool-type valves, if the spool remains stationary, a phenomenon of spool sticking (hydraulic lock) occurs, so a small ripple is added to the input electrical signal when the solenoid is energized. dither is used.

[Problem to be solved by the invention]

However, in the case of the conventional structure, as shown in Fig. 5, the horizontal axis represents the spool movement amount S, and the vertical axis represents the solenoid coil suction force F to represent the relationship between the two.As the suction force increases, the spool returns to the It moves while compressing the spring, and when it comes into contact with the stroke end of the spool or the stopper member, the spool stops and only the suction force increases.If a dither is applied to this structure, F ₁ - as shown in Figure 5.
Since only the suction force between _F3 acts on the spool, the spool has poor response and cannot be vibrated sufficiently.

It is also possible to make the return spring strong and determine the stroke end of the spool by the balance between the return spring and the suction force, but in this case, as shown in Figure 6, the suction force between F ₂ and F ₃ is applied to the vibration of the spool. Although it can be used, the spring stiffness of the return spring is low, so it tends to be a spring with uneven spring constant, and S ₂
−S ₃ becomes S ₂ ′−S ₃ ′, S ₂ ″− by springs L′, L″, L
This has the disadvantage of being significantly different from S ₃ ″ and S ₂ −S ₃ .

The present invention aims to eliminate these disadvantages.

[Means to solve the problem]

The gist of the present invention will be explained with reference to the accompanying drawings.

Recesses 14 are provided at both left and right ends of a valve body 22 provided with a plurality of fluid inlets and outlets 15, and a spool 3 for opening and closing the fluid inlets and outlets 15 is slidably internally installed in the valve body 2, and the ends of the spool 3 are placed in the recesses. 14, a solenoid 4 having a plunger 11 that can be projected and retracted is disposed on both sides of the valve body 2, and the end of the plunger 11 of the solenoid 4 is brought into contact with the end surface of the spool 3 in the recess 14. the spool 3 by fitting the spring seats 6 near the left and right ends of the spool 3, respectively.
The spring seat 6 is provided so as to be pushed as the spring slides.
A return coil spring 8 is fitted onto each spring seat 6 and plunger 11, and the return coil spring 8 is supported by the receiving portion 16 of the spring seat 6 and the opposing solenoid 4, and a disc spring 10 is fitted onto the plunger 11 of each solenoid 4. The base of the disc spring 10 is supported by the mounting end face of the solenoid 4, and the length of the disc spring 10 is adjusted so that the tip of the spring seat 6 contacts the opposing tip of the disc spring 10 near the stroke end of the spool 3. A dither operation mechanism is provided which applies a dither to the end of the spool 3 on the opposite side to the sliding direction of the spool 3 when the spool 3 slides and the spring seat 6 comes into contact with the disc spring 10. The present invention relates to a spool-type electromagnetic directional switching valve characterized by being provided in a solenoid 4.

[Effect]

When the plunger 11 of one solenoid 4 protrudes and the spool 3 slides, the spring seat 6 is pushed against the return coil spring 8 in the recess 14 on the opposite side of the protruding plunger 11 as the spool 3 slides. The reaction force of the disc spring 10 (projection force of the plunger 11) acts on the spring seat 6 near the spool end of the spool 3, and at the same time, the dither is moved by the dither operation mechanism to the side opposite to the sliding direction of the spool 3. Vibration is applied to the end of the spool 3 via the plunger 11, and vibration is applied to the spool 3 from both sides by the reaction force of the disk spring 10 and dither, so that the hydraulic locking phenomenon of the spool 3 is prevented.

〔Example〕

1 to 4 show embodiments of the present invention, and reference numeral 1 denotes a spool-type electromagnetic directional control valve, in which a spool 3 can be slid into a valve body 2. A solenoid 4 is provided at both the left and right ends of the valve body 2, and a spring seat 6 with a receiving part 16 (flange part in the embodiment) is inserted and locked into the stepped part 5 at both the left and right ends of the spool 3, and the spring A return coil spring 8 is provided between the seat 6 and the intermediate member 7, and the spring seat 6
Four disc springs 10 are loosely inserted into the plunger 11 of the solenoid 4 between the outer end surface 9 of the solenoid 4 and the intermediate member 7.

Reference numeral 12 is a coil, and reference numeral 13 is an iron core.

Since this embodiment has the above configuration, one solenoid 4 is in the neutral position of the spool 3 in FIG.
When energized, plunger 1 is activated by the attraction force of the coil.
1 makes a protruding motion, and the spool 3 slides.At this time, the return coil spring 8 is first compressed, and the spool 3
The end face 9 of the spring seat 6 compresses the disc spring 10 near the moving end of the spring seat 6, and the spool 3 is switched and slid as shown in FIG. The relationship between the spool movement amount S and the coil attraction force F in this embodiment is as shown in _{FIG .}
It can be used for the vibration of the spool 3, an effective dither effect can be obtained, and the spool 3, Regardless of the dimensional difference between the valve body 2 and the disc spring 10, it is possible to create a structure in which the disc spring 10 begins to deflect from a position Sf that is minus the free length of the disc spring 10 from the stroke end Se in FIG. It is possible to oscillate between a predetermined range of S ₂ -S ₃ .

Although the above embodiment shows a so-called double solenoid type electromagnetic valve, it can also be applied to a single solenoid type electromagnetic valve.

〔Effect of the invention〕

As described above, in the present invention, the return coil spring is first compressed, and the end face of the spring seat near the moving end of the spool compresses the disc spring, and at the same time, a dither is applied. Therefore, an effective dither effect can be obtained, and rigidity variations can be reduced. It is possible to use the unique effect of a disc spring, which has a small amount of deflection, and the unique effect of a coil spring, which allows for a large amount of deflection, and also allows the disc spring to have freedom from the stroke end, regardless of the dimensional difference between the spool, the valve body, and the disc spring. It is possible to create a structure in which the disc spring starts to accumulate from a position where the length is negative, so that a dither effect can be obtained in a predetermined area, and therefore the spool can be effectively vibrated.

As described above, the present invention can fully achieve the intended purpose of preventing the hydraulic lock phenomenon.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is an overall sectional view, FIG. 2 is a partial sectional view, FIG. 3 is a partial sectional view, and FIG. 4 is a diagram showing the spool and suction force. 5 and 6 are relationship diagrams between the spool of the conventional structure and the suction force. 2...Valve body, 3...Spool, 4...Solenoid,
6... Spring seat, 8... Return coil spring, 10... Belleville spring, 11... Plunger, 14... Recess, 15... Fluid inlet/outlet, 16... Receiving part.

Claims (1)

[Claims] 1 Recesses 14 are provided at both left and right ends of the valve body 2 provided with a plurality of fluid inlets and outlets 15, and a spool 3 that opens and closes the fluid inlets and outlets 15 is slidably internally installed in the valve body 2, and the ends of the spool 3 are recessed. A solenoid 4 having a plunger 11 that can be projected and retracted is disposed on both sides of the valve body 2, and the end of the plunger 11 of the solenoid 4 is connected to the end face of the spool 3 in the recess 14. The spring seats 6 are fitted near the left and right ends of the spool 3, respectively, and the spool 3
The spring seat 6 is provided so as to be pushed as the spring slides.
A return coil spring 8 is fitted onto each spring seat 6 and plunger 11, and the return coil spring 8 is supported by the receiving portion 16 of the spring seat 6 and the opposing solenoid 4, and a disc spring 10 is fitted onto the plunger 11 of each solenoid 4. The base of the disc spring 10 is supported by the mounting end face of the solenoid 4, and the length of the disc spring 10 is adjusted so that the tip of the spring seat 6 contacts the opposing tip of the disc spring 10 near the stroke end of the spool 3. A dither operation mechanism is provided which applies a dither to the end of the spool 3 on the opposite side to the sliding direction of the spool 3 when the spool 3 slides and the spring seat 6 comes into contact with the disc spring 10. A spool type electromagnetic directional control valve characterized by being provided in a solenoid 4.