JPS6364674B2 - - Google Patents

Description

Detailed Description of the Invention (a) Object of the Invention (Technical Field of the Invention) The present invention relates to a plunger-type solenoid valve that drives a valve body by a plunger that reciprocates inside an excitation coil, and more specifically, to This invention relates to a sliding guide portion of a plunger.

(Technical Background of the Invention) Since the plunger frequently slides back and forth inside the excitation coil, the plunger must be able to slide smoothly over a long period of time, and the magnetic resistance between the plunger and the yoke must be designed to improve magnetic efficiency. is required to be as small as possible.

(Prior art and its problems) In order to meet such demands, a configuration as shown in FIG. 1 has conventionally been generally adopted. That is, a non-magnetic guide sleeve 3 is inserted into the inner periphery of a bobbin 2 around which an excitation coil 1 is wound, and a plunger 4 is slid therein. A valve body 5 is attached to the plunger 4 and opens and closes a valve seat 6. A fixed iron core 7 is fixedly installed at the upper end of the guide sleeve 3 and is fixed to a yoke plate 8 at the upper end of the excitation coil. Further, a yoke plate 9 is arranged at the lower end of the excitation coil 1,
The lower end of the guide sleeve 3 is inserted into the circular hole of the yoke plate 9. And upper and lower yoke plates 8, 9
is a yoke frame 1 surrounding the outside of the excitation coil 1
It is magnetically connected to the upper and lower ends of 0.

When the excitation coil 1 is not energized, the valve body 5 is pushed down by the return spring 11 and comes into contact with the valve seat 6 to close the valve, as shown in the figure. However, excitation coil 1
When energized, the magnetic flux passes through a closed loop of yoke frame 10 - yoke plate 8 - fixed core 7 - plunger 4 - yoke plate 9 - yoke frame 10 to minimize the magnetic resistance between fixed core 7 and plunger 4. , the plunger 4 is attracted to the fixed iron core 7. In this way, the plunger 4 is pulled up against the return spring 11 to open the valve.

By the way, the guide sleeve 3 is the plunger 4.
The plunger 4 is required to have low friction and wear so as to withstand frequent sliding, and the plunger 4 must be able to slide smoothly inside the long guide sleeve 3. However, as the guide surface becomes wider, it becomes more difficult to obtain flatness with high precision, so the gap between the guide sleeve 3 and the plunger 4 must be increased to some extent over the entire length of the guide sleeve 3. As a result, the magnetic resistance increases by the gap between the guide sleeve 3 and the plunger 4, and the magnetic efficiency decreases. Further, the guide sleeve 3 must maintain its strength over its entire length and must endure wear even after long-term use, so it is necessary to increase the wall thickness to some extent. In this case, the magnetic resistance increases by the thickness of the non-magnetic guide sleeve 3, and together with the increase in the gap, the magnetic efficiency is further reduced. the result,
In order to obtain sufficient driving force, the ampere-turn of the excitation coil 1 must be increased, which increases the size of the solenoid valve and increases power consumption and heat generation.

Furthermore, since the gap between the guide sleeve 3 and the plunger 4 must be enlarged, the gap is likely to expand due to wear, and the looseness will rapidly increase and vibrations will become more intense.

(Technical Problem of the Invention) A technical problem of the present invention is a plunger-type electromagnetic valve in which a valve body is driven by a plunger reciprocating inside an excitation coil. The objective is to improve magnetic efficiency by minimizing the gap.

(b) Structure of the invention (technical means of the present invention) The technical means of the present invention for solving this technical problem is a plunger type that drives a valve body by a plunger that reciprocates inside an exciting coil. This electromagnetic valve includes a first fixed core disposed on the opposite side of the valve body and a second fixed core disposed on the valve body side, and the plunger is inserted into a guide hole of the first fixed core. The valve body side of the plunger is structured to be inserted into the second fixed core, and the plunger guide shaft is located at a position on the inner surface of the guide hole of the first fixed core where the plunger guide shaft slides. A thin film sliding material with low friction and low wear is provided on the inner surface of the plunger insertion portion of the second fixed core, and the second fixed core is provided with a thin film sliding material with low friction and low wear. It is provided so as to be movable relative to the yoke member forming the circuit, and is elastically pressed against the yoke member forming the magnetic circuit.

(Operation of technical means) FIG. 2 is a longitudinal sectional view for explaining the operation of the technical means of the present invention in an easy-to-understand manner, and parts corresponding to those in FIG. 1 are given the same reference numerals. The first fixed iron core 7 has a guide hole 71 opened in its axial direction, and a nonmagnetic guide shaft 41 fixed to the plunger 4 is inserted into the guide hole 71. A thin film sliding material 12 with low friction and low wear is provided on the inner surface of the guide hole 71 at the position where the guide shaft 41 slides.
is provided.

Further, the second fixed iron core 13 has a substantially cylindrical shape, into which the lower end of the plunger 4 is inserted. A low-friction, low-wear thin film sliding material 14 is also provided on the inner surface of the second fixed core 13 at a position on which the plunger 4 slides. A valve body 5 is connected to the lower end of the plunger 4 via a valve stem 15. The second fixed iron core 13 is not fixed to the yoke plate 9, but is separated so that it can be moved mechanically. Then, it is pressed against the yoke plate 9 side by a return spring 11.

When the excitation coil 1 is energized now, the magnetic flux flows through the yoke frame 10 - yoke plate 8 - first fixed iron core 7
- Plunger 4 - Second fixed iron core 13 - Yoke plate 9 - Yoke frame 10 pass through a closed loop, and in order to minimize magnetic resistance between first fixed iron core 7 and plunger 4, plunger 4 connects to first fixed iron core. 7 is adsorbed. In this way, the plunger 4 is pulled up against the return spring 11 to open the valve.

The plunger 4 is slidably guided only in limited areas at the upper and lower ends, and the entire length of the plunger 4 is not slidably guided as in the conventional case. That is, at the upper end of the plunger 4, the guide shaft 41 is slidably guided by the low-friction, low-wear thin film sliding material 12 on the inner surface of the guide hole 71 of the first fixed iron core 7. The lower end of the plunger 4 is a low-friction, low-wear thin film sliding material 1 on the inner surface of the second fixed core 13.
4 is slidingly guided. Since the sliding area of the plunger 4 is short in this way, it is possible to finish it with high precision so that the gap between the plunger 4 and the low-friction, low-wear thin film sliding material 14 of the second fixed iron core 13 is extremely small. can. Magnetic resistance is therefore significantly reduced. Also, low friction and low wear thin film sliding material 1
4, the sliding guide area of the plunger 4 is short, it can be guided with high precision, and the mechanical strength is small, so the wall thickness can be made extremely thin, and as a result, the magnetic field between the plunger 4 and the second fixed iron core 13 is reduced. The resistance is much lower and the magnetic efficiency is greatly improved.

Furthermore, the second fixed iron core 13 is movable relative to the yoke plate 9 and is only pressed by the return spring 11. Therefore, even if the outer periphery of the plunger 4 and the low-friction, low-wear thin film sliding material 1
Even if there is deviation in contact with the inner circumference of the plunger 4, the second fixed iron core 13 follows the plunger 4 and is displaced so that the sliding guide is most stable. Due to the movability of the second fixed iron core 13, the gap with the plunger 4 can be further reduced, and magnetic resistance, friction, and wear are significantly improved.

(c) Effects of the Invention As described above, according to the technical means of the present invention, the magnetic resistance is extremely reduced and the magnetic efficiency is improved, so that a small solenoid valve with a large driving force can be realized.
Furthermore, since it is small, power consumption is low and heat generation is reduced. Furthermore, since the gap between the plunger and its guide becomes smaller, there is less backlash, and vibration and noise are also reduced.

(d) Embodiments of the Invention FIG. 3 is a cross-sectional view showing a low-friction, low-wear thin film sliding material 12 provided in the guide hole 71 of the first fixed iron core 7. FIG. 4 is a sectional view showing a low-friction, low-wear thin film sliding material 14 provided on the inner surface of the second fixed iron core 13. Low friction, low wear thin film sliding material 1
4 and 12 may be provided by press-fitting thin-walled cylinders, or by providing the second fixed core 13 and the first
The inner surface of the fixed core 7 may be coated or coated with a low-friction, low-wear material.

When the spring receiver 16 is interposed between the second fixed iron core 13 and the return spring 11, stability is improved. Second
The spring for pressing the fixed iron core 13 against the yoke plate 9 also serves as the return spring 11 of the valve body.
A dedicated spring or elastic body may also be used.

Further, the yoke frame 10, the yoke plate 8, and the yoke plate 9 can all be formed integrally, and the structure of the abutting portion between the yoke member and the second fixed iron core 13 is also such that the yoke member and the second fixed core 13 are magnetically coupled and mechanically coupled. There is no particular restriction as long as it can be engaged with.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of a conventional plunger type solenoid valve, Fig. 2 is a longitudinal sectional view of the electromagnetic valve for explaining the action of the technical means according to the present invention, and Fig. 3 is a longitudinal sectional view of the solenoid valve on the first fixed core side. FIG. 4 is a cross-sectional view showing the guide portion of the second fixed iron core and the plunger. In the figure, 1 is an excitation coil, 4 is a plunger, 41 is a guide shaft, 5 is a valve body, 7 is a first fixed core, 71 is a guide hole, 11 is a return spring, 13 is a second fixed core, 12, 14 indicates a thin film sliding material with low friction and low wear.

Claims (1)

[Scope of Claims] 1. A plunger-type solenoid valve in which a valve body is driven by a plunger that reciprocates inside an excitation coil, comprising: a first fixed iron core disposed on the opposite side of the valve body; The plunger is provided with a guide shaft inserted into the guide hole of the first fixed iron core, and the valve body side of the plunger has a structure that is inserted into the second fixed iron core. A thin film sliding material with low friction and low wear is provided on the inner surface of the guide hole of the first fixed iron core at the position where the plunger guide shaft slides, and a thin film sliding material with low friction and low wear is provided on the inner surface of the plunger insertion part of the second fixed iron core. is provided with a thin film sliding material with low friction and low wear, and the second fixed iron core is provided so as to be movable relative to the yoke member forming the magnetic circuit, and the second fixed iron core is provided so as to be movable relative to the yoke member forming the magnetic circuit. A plunger type solenoid valve that is elastically pressed against the side.