JP2000046225A - Solenoid valve - Google Patents

Abstract

(57) [Summary] [Problem] To not increase the size of a solenoid valve. SOLUTION: A housing 5, a yoke 2.3 disposed inside the housing 5 and having a coil wound around 22 outside, and a plunger 4 coaxially and slidably disposed in the yoke 2.3. In a solenoid valve in which the plunger 4 is slidably variable according to the amount of electricity supplied to the coil 22, at least one of the inner peripheral surfaces of the yokes 2 and 3 and the outer peripheral surface of the plunger 4 is coated. thing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve used for a vehicle transmission and the like.
The present invention relates to a linear solenoid valve that slides in a linear state by varying the amount of current supplied to a coil.

[0002]

2. Description of the Related Art A conventional solenoid valve of this type is disclosed, for example, in Japanese Patent Application Laid-Open No. Hei 6-123378. The solenoid valve includes a coil wound on a bobbin, a first yoke supporting the bobbin, and a second yoke.
A yoke, a plunger supported on both sides by bearings provided on the first yoke and the second yoke and sliding by energizing the coil, and an outer periphery of the coil disposed between the first yoke and the second yoke And a housing provided to cover the housing.

[0003] However, for smooth linear movement of the plunger, it is necessary to magnetically isolate the plunger from the yoke. For this reason, in this prior art,
An air gap is formed between the plunger and the yoke, and the air gap is magnetically isolated between the two.

[0004]

However, in the above-described conventional solenoid valve, the plunger is supported on both sides in the axial direction by the shaft by the bearings fixed to the first yoke and the second yoke. If the plunger is tilted due to an error or the like, the plunger may come into contact with the yoke, and the air gap must be set large so that such a situation does not occur. Then, there is a problem that the solenoid valve becomes large.

Accordingly, an object of the present invention is to provide a solenoid valve which does not cause the above-mentioned problems.

[0006]

The technical measures taken to solve the above-mentioned problems include a housing, a yoke disposed inside the housing and having a coil wound outside, and a coaxial and coaxial inside the yoke. A plunger slidably disposed, wherein the plunger is variably slid according to the amount of current supplied to the coil, wherein at least one of the inner peripheral surface of the yoke and the outer peripheral surface of the plunger is coated. That is, the processing has been performed.

[0007]

Operation and effect By adopting the above configuration, an infinitely thin film can be formed between the plunger and the yoke, and this thin film can establish a magnetic separation between the plunger and the yoke. Thus, the conventional problems are eliminated.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of a solenoid valve 1 used for an automatic transmission or the like of a vehicle when power is not supplied. In FIG. 1, a description will be given below. A yoke 3 made of the same material as the yoke 2 is compared with a cylindrical yoke 2 having a flange 2 a made of an iron-based magnetic material (eg, SUM) at one end. It is fixed by press fitting. In this case, the boss 3b hollow in the axial direction of the yoke 3 is
The yoke 2 is inserted into the inner diameter 2c of the yoke 2 by press-fitting.
b is formed.

In the yoke 2, a non-magnetic member 2b is integrally provided near the position where the step 3b is formed by processing. The non-magnetic portion 2b is provided in an annular shape in the circumferential direction of the yoke 2 by adding nickel or the like to a material such as iron forming the yoke 2 and irradiating the material with a laser beam. In other words, the method of providing the non-magnetic portion 2b is specifically described below. A nickel foil is wound around a modified portion of the yoke 2 which is a ferromagnetic material such as iron (a portion to be the non-magnetic portion 2b). Is irradiated with laser light to alloy nickel, and the portion is modified to austenite (non-magnetic or weakly magnetic).

A coil 22 is wound around the outer periphery between the flanges 2a, 3a on both sides of the yokes 2, 3 integrated by press-fitting with a material having good conductivity (such as nichrome wire). The ends are welded by fusing to and electrically connected to substantially L-shaped terminals 6 (only one is shown) different from each other.

The sub-assembly 13 is formed by inserting the yokes 2 and 3, the coil 22, the terminal 6, and the like into a mold and performing resin molding. In this case, it is preferable to use 6-6 nylon for the resin in order to improve the heat resistance in the resin molding, and to include glass in order to improve the strength with respect to the 6-6 nylon. In the sub-assembly 13 formed of resin in this way, the yokes 2 and 3 and the coil 22 are integrated with the resin, and the connector 8 is formed integrally.

A plunger 4 made of a magnetic material such as SUM, which is slidable along the inner diameter 2c of the yoke 2, is provided for the sub-assembly 13 thus formed. The plunger 4 has a step 4c on one side in the sliding direction (left side shown in FIG. 1). Also, plunger 4
In a state in which a non-magnetic stopper 7 for restricting the movement in one direction is fitted from one side, a housing 5 made of a cylindrical cold-rolled steel plate having a bottom (for example, a pressed material such as SPCC) is provided. , A sub-assembly 13 is provided.

In this case, the sliding surface of the outer circumference of the plunger 4 or the inner circumferences 2c and 3c of the yokes 2 and 3 is coated with a Teflon-based coating to reduce the sliding resistance. Due to the Teflon-based coating process, a thin film for magnetically isolating the outer periphery of the plunger 4 and the inner periphery 2c of the yoke 2 (the inner periphery 3c of the yoke 3) is formed as thin as possible. Since the plunger 4 is restricted in one direction by the non-magnetic stopper 7, the plunger 4 is attached to the step 3 b of the yoke 3.
Of the yoke 2 within the range until the step 4c of the
It is possible to slide along c. The plunger 4 is a step 4c
A guide surface 4a is formed along the inner diameter 3c of the yoke 3, and a tapered surface 4b is provided from the guide surface 4a to a radially flat tip. The tapered surface 4b is provided at a constant angle θ with respect to the guide surface 4a, and is desirably provided at an inclined angle at which a magnetic field is easily formed when the coil is energized.

A sub-assembly 13 is provided in the housing 5, the yoke 2 is engaged with the housing 5, and the coil 2
A cylindrical valve body 10 made of aluminum or the like is disposed so as to contact the side surface of the flange 3a of the yoke 3 with the outer periphery of the housing 2 closed, and the end of the housing 5 is attached to the valve body 10. And fix by caulking.

The valve body 10 has a plurality of ports 23,
24, 25, 26, etc., are provided so that the spool valve 15 slides in the cylinder portion 10a inside the valve body 10. The spool valve 15 has a communication hole 15c for communicating the ports 24 and 26 at one location inside.
Is provided. A threaded hole is provided at an end of the valve body 10, one end of a compression spring 19 is locked to a plug 17 screwed into the hole, and the spool valve 15 is attached to the right side shown in FIG. It is being rushed. The valve body 10 has an input port 24, an output port 23, and a drain port 25 for switching a hydraulic circuit inside the automatic transmission.
Is provided, so that the movement of the plunger 4
Large diameter portion 15a (diameter: d1) and small diameter portion 15b in the axial direction
The spool valve 15 having a diameter (d2) is pushed (see FIG. 2) so that the ports communicate with each other so that the adjustment pressure can be supplied to the outside. The relationship between pressure and force is as follows. That is, spring reaction force: Fk, Fm: force applied to plunger 4 (proportional to current), output port 23
Fk = Fm + π / 4 · P · (d1
-D2) It becomes ² .

The plunger 4 is in contact with the right end 15d of the spool valve 15 which receives the urging force from the compression spring 19 at the left end shown in FIG. 1, and the right end of the plunger 4 is regulated by the non-magnetic stopper 7. Then, it comes into contact with the non-magnetic stopper 7.

Next, the operation of the solenoid valve 1 will be described. When the coil 22 is not energized from the outside through the terminal 6 of the connector 8, the plunger 4 receives the rightward biasing force from the compression spring 19, so that the spool valve 15 is pressed rightward, and the plunger 4 is disengaged. It comes into contact with the magnetic stopper 7 (see FIG. 1).

When the coil 22 is energized in this state, an attractive force is generated between the yokes 2, 3 and the plunger 4 according to the magnitude of the current flowing through the coil 22. That is, by energizing the coil 22, the yoke 2, the plunger 4, and the yoke 3,
A magnetic field H is generated around the housing 5. In this case, since the yoke 2 is provided with the non-magnetic material portion 2b integrally and the step portion 3b is provided near the non-magnetic material 2b, no magnetic field passes through the non-magnetic material portion 2b, Since the magnetic field does not pass directly from both sides of the body part 2b, and the magnetic field is generated via the plunger 4, the plunger 4
, The spool valve 15 is pushed leftward. In this case, the attraction force corresponding to the amount of current (current) supplied to the coil 22 and the compression spring 1
The spool valve 15 moves to a position where the urging force of the spool 9 is balanced, and the pressure regulated by the moving position of the spool valve 15 is generated in the port and can be supplied to the outside.

In the first embodiment, the coils 22
The yokes 2 and 3 around which are wound are provided by press-fitting. However, as shown in FIG. 3, a yoke 12 in which the shapes of the yokes 2 and 3 are integrated is provided. If it is provided in an annular shape by processing, the number of parts can be reduced and coaxiality can be more easily obtained.

As shown in FIG. 4, the bobbin 50 is provided with an extending portion 50a, and the extending portion 50a is fitted into a hole 2x formed in the yoke 2 to form the non-magnetic material portion 2b.
May be used as an alternative configuration.

[Brief description of the drawings]

FIG. 1 is a sectional view of a solenoid valve according to a first embodiment of the present invention when power is not supplied.

FIG. 2 is a sectional view of the solenoid valve according to the first embodiment of the present invention when energized.

FIG. 3 is a sectional view of a solenoid valve according to a second embodiment of the present invention.

FIG. 4 is a partial cross-sectional view showing a modification of the non-magnetic member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solenoid valve 2,3,12 Yoke 2b, 12b Non-magnetic part 2c, 3c Inner diameter 4 Plunger 5 Housing 10 Valve body 15 Spool valve 23 Output port 24 Input port

Claims (2)

[Claims] 1. A housing, a yoke disposed inside the housing and wound around a coil, and a plunger disposed coaxially and slidably in the yoke, the amount of electricity supplied to the coil. A solenoid valve, wherein the plunger is slidably slidable, wherein at least one of an inner peripheral surface of the yoke and an outer peripheral surface of the plunger is subjected to a coating process. 2. The solenoid valve according to claim 1, wherein the coating process uses a Teflon-based material.