JP2002272080A - Solenoid-type actuator with shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress vibration and noise due to impact produced when a solenoid actuator is in action and simplify the structure of coupling between a plunger and a shaft. SOLUTION: An enclosed space 42 is formed at the upper part of the plunger 17 inside the cylindrical inner face 27 of a fixed core 25. The space 42 is communicated to a space at the lower part of the plunger 17 through an orifice 19 comprising the gap between the center hole 18 in the plunger 17 and the small- diameter portion 15 of the shaft 10 and the like. An air damper is constituted of the space 42 and the orifice 19, and rapid movement of the plunger 17 is damped. Therefore, impact is not produced when a valve body 11 is seated on a valve seat 9 and other occasions, and production of vibration and noise is prevented. Owing to the air damper, instantaneous exertion of large load on the joint between the plunger 17 and the shaft 10 is eliminated, and a simple structure in which detachment and attachment are facilitated can be adopted instead of integral junction, such as welding, press fit, and caulking.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid type actuator with a shaft used for an electromagnetic valve or the like.

[0002]

2. Description of the Related Art In a solenoid valve or the like having a solenoid type actuator, a reciprocating motion occurs in a cylindrical fixed iron core due to a force relationship between an electromagnetic force of the solenoid and an elastic force of a spring opposing the solenoid. A plunger made of a magnetic material such as iron is used as a driving body, but in order to transmit the displacement of the plunger to a driven body such as a valve body, the other end of a shaft having a valve body attached to one end is used. It is integrally and firmly fixed to the center hole of the plunger by press fitting, welding or caulking. In such a conventional solenoid valve, a large impact force is generated in the axial direction of the shaft when the valve body is seated on a valve seat, for example, when the valve is closed. Must be firmly bonded as described above.

The space inside a cylindrical fixed iron core made of a magnetic material such as iron, which is provided to allow the magnetic flux generated by the solenoid to act on the plunger and to slidably guide the plunger, The upper and lower spaces are separated by a plunger, which is a movable iron core, but the upper and lower two spaces are not mutually sealed. Usually, there is a large gap between the plunger and the fixed iron core, around the solenoid or the fixed iron core. Since they are in communication with each other through the formed gaps and the like, the movement of the plunger is not hindered by the air in those spaces.

[0004]

As described above, in the conventional solenoid valve, a large impact force is generated when the valve is closed and opened, particularly when the valve body is seated on a valve seat. There is a problem that vibration and noise are transmitted to the surroundings by force. Further, it is necessary to firmly and integrally connect the shaft to the plunger, which is a movable iron core, by a method such as welding or press fitting so as to withstand the impact force.

According to the present invention, in order to solve such a problem in a solenoid type actuator with a shaft typified by a conventional solenoid valve, an impact force generated during operation is effectively suppressed, and vibration and noise are transmitted to the surroundings. It is an object of the present invention to provide a solenoid actuator with a shaft having a simple structure that does not need to be firmly connected with a plunger as a movable iron core and a shaft to which a driven body is attached.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided a solenoid type actuator having a shaft as described in claim 1 as a means for solving the above-mentioned problems in the prior art. provide.

In the solenoid type actuator with a shaft according to the present invention, a closed space is formed in the upper portion of the plunger inside the cylindrical portion of the fixed iron core, and this space is formed through the orifice having a small passage area. It communicates with the space. Since the upper space of the plunger communicates with the lower space of the plunger only by the orifice, when the plunger moves up and down along the cylindrical inner surface of the fixed iron core, the space between the upper space and the lower space of the plunger is changed. The movement of air through the orifice occurs between them, but the flow area of the orifice is so small that its fluid resistance dampens the rapid movement of the plunger. That is, the space above the orifice and the plunger operates as an air damper for the plunger.

Accordingly, the driven body connected to the plunger by the shaft is also restrained from moving rapidly, so that the movement of the driven body suppresses the generation of an impact force, thereby preventing the generation of vibration and noise due to the impact force. . Further, since the impact force is reduced by the air damper, a large load is not instantaneously applied to the joint portion between the plunger and the shaft, so that the relative movement in the axial direction provided between the plunger and the shaft is prevented. Is not an integral joint such as welding, press-fitting or caulking, but a simple structure that can be easily attached and detached.

An orifice for communicating a closed space formed at an upper portion of the plunger with a space formed at a lower portion thereof is loosely inserted while leaving a small gap in a hole formed in the plunger. By taking the structure that
It can easily be formed as a gap between a part of the shaft and a slightly larger hole. However, the orifice can be formed by other means such as providing a small diameter through hole in the plunger.

As one preferred embodiment of the solenoid type actuator with a shaft of the present invention, an actuator for a solenoid valve can be constituted by attaching a valve body as a driven body to the tip of the shaft.
As another preferred embodiment of the present invention, the solenoid type actuator with a shaft can be applied to a switch or a clutch.

In practicing the present invention, specifically, means for preventing relative movement in the axial direction between the plunger and the shaft are provided at the step formed on the shaft and at the tip of the shaft. It can be constituted by retaining. If the retainer in this case is composed of an annular groove formed in the shaft and a snap ring that engages with the groove, not only the structure can be simplified, but also it can be easily disassembled, so that maintenance and inspection can be performed. Becomes easier.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A solenoid valve 1 provided with a preferred embodiment of a solenoid type actuator with a shaft according to the present invention will be described with reference to FIG. The solenoid valve 1 specifically belongs to an air switching valve (ASV) for intermittently controlling the flow of air. Although the inlet 3 and the outlet 4 are formed in the main body 2 of the valve, the inlet 3 and the outlet 4 may be alternated. The inlet 3 is connected to an air cleaner or the like of an internal combustion engine (not shown) by a pipe to introduce clean air into the main body 2. The outlet 4 is connected to an exhaust manifold 39 of the same internal combustion engine so that the air that has passed through the solenoid valve 1 is mixed into the exhaust gas as secondary air. In the case of the illustrated embodiment, the outlet 4 is provided with a reed valve 5 which is a check valve and a stopper 6 for protecting the same. The reed valve 5 reliably prevents exhaust gas from being blown back. Of the exhaust gas is protected from the heat of the exhaust gas and foreign substances such as fine particles contained therein.

A valve seat 9 having an opening 8 is formed in a partition wall 7 partitioning between the inlet 3 and the outlet 4. Valve seat opening 8
A valve shaft (shaft) 10 made of stainless steel is supported at a position where the center substantially coincides with the center, and a disc-shaped valve body 11 is integrated with a lower end of the valve shaft 10 by a method such as caulking or welding. . In addition, an annular seal rubber 12 is attached to a peripheral portion of the valve body 11 that comes into contact with the surface of the valve seat 9 in order to enhance the sealing performance when the valve is closed. An intermediate portion of the valve shaft 10 is supported by a bush 13 as a bearing so as to be slidable in the axial direction. Reference numeral 14 denotes a seal for preventing dust and the like from entering the bush 13 and causing trouble. The flange portion of the bush 13 functions as a spring holder and also as a stopper for controlling the stroke between the valve shaft 10 and the valve element 11.

A portion near the upper end of the valve shaft 10 is a small-diameter portion 15 having a slightly reduced diameter, and a step portion 16 is formed between the small-diameter portion 15 and an intermediate large-diameter portion. The small diameter portion 15 of the valve shaft 10 is loosely inserted into a center hole 18 of a cylindrical plunger 17 made of a magnetic material such as iron. The plunger 17 may be a permanent magnet made of a ferromagnetic material. The inner diameter of the center hole 18 of the plunger 17 is slightly larger than the outer diameter of the small diameter portion 15 of the valve shaft 10, and as a small annular gap between them,
An orifice 19 having a small passage area is formed.

After the small-diameter portion 15 of the valve shaft 10 is loosely inserted into the center hole 18 of the plunger 17, the tip of the small-diameter portion 15 is provided with a stopper 20. The retainer 20 in the illustrated embodiment is a simple and detachable one in which a snap ring 22 is radially mounted in an annular groove 21 formed at the tip of the small diameter portion 15. It is not limited to such a thing.
Other than 0, various structures may be used, such as forming an external thread at the tip of the small diameter portion 15 of the valve shaft 10, screwing the nut to the nut, and then turning the nut with a pine needle pin. Can be. At that time, 20
A washer may be fitted to a portion where the enlarged part of the plunger 17 comes into contact with the upper surface of the plunger 17.

Prior to assembling, a compression spring 24 is previously mounted between a flange portion 23 formed on the bush 13 and the lower surface of the plunger 17. The flange portion 23 of the bush 13 has a stepped portion 26 formed at the lower end of a substantially cylindrical fixed iron core 25 made of a magnetic material such as iron.
Supported by The cylindrical inner surface 27 of the fixed core 25 has an inner diameter slightly larger than the outer diameter of the plunger 17, thereby guiding the plunger 17 movably in the axial direction of the valve shaft 10. A solenoid (coil) 28 is wound around a plastic bobbin 29 and fixed around the fixed iron core 25.

A disk portion 30 integrally enlarged in the radial direction from the lower end of the fixed iron core 25 is supported by a step portion 31 of the valve body 2. The housing 32 of the actuator integrally mounted at right angles to the body 2 of the valve is substantially cylindrical,
A cylindrical yoke 33 having a bottom and made of a magnetic material such as iron is provided around a solenoid 28 inside the peripheral portion of the disk portion 30 so as to be an extension of the fixed iron core 25 and an upper portion of the center portion. Are in contact with each other. The solenoid 28
Is connected to the terminal 37 in the connector 35 through the opening 36 of the yoke 33. Fixed iron core 2
A cutout 38, such as an annular groove, is formed outside the center of 5.

As is apparent from the cross-sectional shape shown in FIG. 1, a current flows through the solenoid 28, thereby
When the magnet 5 is magnetized, a magnetic flux is formed in a donut-shaped closed magnetic circuit constituted by the fixed iron core 25 and the yoke 33. Since this magnetic circuit is constricted in the vicinity of the notch 38 of the fixed iron core 25, the magnetic flux concentrates near the notch 38 and the magnetic flux density increases. Therefore, the plunger 17 is magnetically attracted and moves toward the portion where the magnetic flux density is high, so that the plunger 17 descends against the urging force of the spring 24. At that time, the plunger 17 pushes down the valve shaft 10 by the step portion 16,
The valve body 11 attached to the lower end of the valve shaft 10 opens the opening 8 of the valve seat 9 to open the solenoid valve 1, and the air at the inlet 3 flows to the outlet 4.

In the illustrated embodiment, the valve seat opening 8 is provided.
Since the reed valve 5 is further provided on the downstream side of the valve, the air flowing to the outlet 4 when the solenoid valve 1 is in the open state pushes the reed valve 5 open by the pressure and flows inside the exhaust manifold 39. Flow into the exhaust gas and mix with it.

In accordance with the features of the present invention, in the solenoid valve 1 of the illustrated embodiment, the plunger 17 is not fixedly attached to the valve shaft 10 as described above, and the small diameter portion 15 of the valve shaft 10 Since there is a predetermined size difference between the outer diameter and the inner diameter of the center hole 18 of the plunger 17, the small diameter portion 15 of the valve shaft 10 is provided with a small gap and the center hole 18 of the plunger 17 is provided.
Has been loosely inserted. This gap thereby forms an orifice 19 having a predetermined small passage area. The downward movement of the plunger 17 is caused by the engagement of the lower surface of the plunger 17 with the step 16 of the valve shaft 10, and the upward movement of the plunger 17 is caused by the upper surface of the plunger 17.
This takes place with the valve stem 10 by engagement with a simple catch 20 consisting of an annular groove 21 formed at the upper end of the valve stem 10 and a snap ring 22 fitted therein.

Further, according to another feature of the present invention, the upper end of the fixed iron core 25 having the cylindrical inner surface 27 is formed as follows.
A plastic lid plate 4 integrated with the connector 35 and the like described above.
The space 4 sealed above the plunger 17 is fitted to the downwardly projecting portion 41 formed in a part of the plunger 17.
2 are formed. The space 42 substantially communicates with the space 43 below the plunger 17 only by the orifice 19 described above. Therefore, the plunger 17 is fixed
When moving up and down along the cylindrical inner surface 27 of the plunger 17, air moves through the orifice 19 between the upper space 42 and the lower space 43 of the plunger 17, and the fluid resistance causes the plunger 17 to move. Rapid movement is braked and buffered. That is, the orifice 19 and the closed space 42 constitute an air damper.

As described above, the orifice 19 and the closed space 4
2 operates as an air damper, so that the plunger 17 and the valve body 11 are closed when the valve body 11 is seated on the valve seat 9 or when the valve body is moved away from the valve seat 9 to the maximum lift position.
Is suppressed, no impact force is generated between the valve body 11 and the valve seat 9, and no vibration or noise is generated and transmitted from the electromagnetic valve 1 to the outside. Further, since the impact force is reduced by the air damper, a large load is not instantaneously applied to the joint portion between the plunger 17 and the valve shaft 10. A simple and detachable structure like the groove 21 and the snap ring 22 can be realized.

In the illustrated embodiment, a solenoid-type actuator which specifically drives the valve element 11 of the solenoid valve 1 is taken as an example. However, the present invention is not limited to the solenoid valve, but includes a switch, a clutch and the like. The present invention can be widely applied to general solenoid type actuators which are also used for driving the actuator. Further, when the present invention is applied to an electromagnetic valve, it is not limited to the electromagnetic valve 1 which merely opens and closes the valve seat opening 8 as in the illustrated embodiment, but is generated in accordance with the amount of current supplied to the solenoid 28. The control valve may be configured to change the valve opening in a stepless manner in balance between the generated electromagnetic force and the urging force generated by the spring 24.

Further, in the illustrated embodiment, the orifice 19 is formed by the gap between the center hole 18 of the plunger 17 and the small diameter portion 15 of the valve shaft 10, but there is substantially no gap between them. For example, a small hole may be provided in the plunger 17 so as to penetrate the plunger 17 in the vertical direction.
The orifice may be formed by utilizing a gap formed in the outer portion of the orifice.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electromagnetic valve 10 ... Valve shaft (shaft) 11 ... Valve body (driven body) 15 ... Small diameter part of valve shaft 16 ... Step 17 ... Plunger 18 ... Center hole of plunger 19 ... Orifice 20 ... Retaining 21 ... Annular Groove 22 ... snap ring 24 ... compression spring 25 ... fixed iron core 28 ... solenoid 42 ... closed space

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shinichi Nitta 1-1-1 Showa-cho, Kariya-shi, Aichi F-term in DENSO Corporation (reference) 3H106 DA07 DA13 DA23 DB02 DB12 DB23 DB32 DC02 DD03 EE19 EE20 EE33 GA13 GA15 GC11 KK04 3J048 AA02 AC04 BE02 CB30 EA20 5H633 BB07 BB08 BB10 GG02 GG04 GG05 GG15 HH03 HH14 JA02 JA04

Claims (6)

[Claims] 1. A solenoid, a fixed core having at least a cylindrical portion and magnetized when the solenoid is energized, and moving inside the cylindrical portion of the fixed core in an axial direction of the cylindrical portion. It comprises a possible plunger, a shaft coupled thereto by means for preventing axial movement relative to the plunger, and a driven body mounted on the shaft and movable together. At the same time, a sealed space is formed above the plunger inside the cylindrical portion of the fixed core, and the space communicates with the space below the plunger via an orifice having a small passage area. A solenoid type actuator with shaft. 2. The orifice according to claim 1, wherein a part of the shaft is loosely inserted into the hole formed in the plunger with a small gap left therebetween to form the orifice between the hole and the shaft. A solenoid-type actuator with a shaft. 3. The solenoid with a shaft according to claim 1, wherein the driven body is a valve body that opens and closes a valve seat opening, and is entirely configured as an actuator for a solenoid valve. Type actuator. 4. The solenoid type actuator with a shaft according to claim 1, which is applied to a switch or a clutch. 5. The shaft according to claim 1, wherein means for preventing relative movement in the axial direction between the plunger and the shaft are provided at a step formed on the shaft and at a tip of the shaft. A solenoid type actuator with a shaft, characterized in that it is provided with a retaining member. 6. The solenoid type actuator with a shaft according to claim 5, wherein the stopper comprises an annular groove formed in the shaft and a snap ring engaged with the annular groove.