JP2008261415A - Solenoid valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration of production efficiency due to the formation of a film 21, in a solenoid valve 1 with the nonmagnetic film 21 formed on the peripheral surface of a plunger 5. <P>SOLUTION: The peripheral surface of the plunger 5 is formed into an uneven shape with projecting portions 19 and recessed portions 20 axially alternated, and the nonmagnetic film 21 is formed on the peripheral surface. Thereby, the plunger 5 is slidably supported on a support portion by opposing the top 23 of each projecting portion 19 to the inner peripheral surface of the support portion through the film 21, and a clearance between the peripheral surface of the plunger 5 and the inner peripheral surface of the support portion becomes larger than the conventional case in a portion other than the top 23. Since the effective value of the clearance is reduced without deteriorating the concentricity of the plunger 5 and support portion, the thickness of the film 21 is reduced. From the foregoing, the deterioration of the productive efficiency accompanied by the formation of the film 21 is prevented by forming the peripheral surface of the plunger 5 into the uneven shape and reducing the thickness of the film 21. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electromagnetic valve that switches a fluid flow path by displacing a spool using a magnetic attraction force generated by energization of a solenoid coil as a driving force.

Conventionally, electromagnetic valves as described above have been used for switching hydraulic circuits in automatic transmissions, adjusting hydraulic pressure in variable valve timing devices, and the like.
The conventional solenoid valve includes a spool that functions as a valve body, a solenoid coil that generates a magnetic attractive force when energized, a plunger that displaces the spool in the axial direction by the magnetic attractive force, and a plunger. Some include a support member that is slidably supported in the axial direction from the outer peripheral side.

  According to this solenoid valve, since the clearance between the outer peripheral surface of the plunger and the inner peripheral surface of the support member can be minimized, the eccentricity of the plunger with respect to the support member can be suppressed, and the magnetic force in the axial direction for displacing the spool can be suppressed. The suction power can be strengthened. However, the magnetic attractive force (side force) acting in the radial direction between the plunger and the support member is strengthened together with the magnetic attractive force in the axial direction. Therefore, in order to suppress an increase in sliding resistance due to side force, as shown in FIG. 3, an electromagnetic valve is disclosed in which a nonmagnetic coating 102 is formed on the outer peripheral surface 101 of the plunger 100 to a predetermined thickness (for example, , See Patent Document 1).

By the way, the coating 102 needs to be formed uniformly in order to suppress the eccentricity of the plunger 100. For this reason, in the production of the solenoid valve, further strengthening of clearance management and surface roughness management and reduction in dimensional tolerance are required, so that the production efficiency of the solenoid valve decreases as the thickness of the coating 102 increases. Therefore, it is conceivable to reduce the thickness of the coating film 102 in order to prevent a decrease in production efficiency due to the formation of the coating film 102, but the plunger 100 is likely to be decentered and the sliding resistance is likely to increase.
JP 2002-222710 A

  The present invention has been made to solve the above-described problems, and an object of the present invention is to reduce the production efficiency associated with the formation of a coating film in a solenoid valve having a nonmagnetic coating film formed on the outer peripheral surface of the plunger. It is to stop.

[Means of Claim 1]
The electromagnetic valve according to claim 1 includes a spool that functions as a valve body, a solenoid coil that generates a magnetic attractive force when energized, a plunger that displaces the spool in the axial direction by the magnetic attractive force, and a plunger And a supporting member that slidably supports in the axial direction from the outer peripheral side. The outer peripheral surface of the plunger has convex and concave portions protruding radially outward and concave portions recessed radially inward in the axial direction to form an uneven shape, and the non-magnetic coating is formed on the uneven outer peripheral surface. Is formed.

Accordingly, the plunger is slidably supported by the support member with the top of the convex portion facing the inner peripheral surface of the support member through the coating, and between the outer peripheral surface of the plunger and the inner peripheral surface of the support member. The clearance becomes larger than that in the past in the portion other than the top of the convex portion. For this reason, since the effective value of the clearance can be reduced without lowering the coaxiality between the plunger and the support member, the eccentricity of the plunger hardly occurs even if the thickness of the coating is reduced.
As described above, in a solenoid valve having a nonmagnetic coating formed on the outer peripheral surface of the plunger, the outer peripheral surface of the plunger is provided in an uneven shape to reduce the thickness of the coating, thereby reducing the production efficiency associated with the formation of the coating. Can be blocked.

[Means of claim 2]
According to the electromagnetic valve of claim 2, the distance between the axis of the plunger and the top of the convex portion is the base material ridge radius r1, and the distance between the plunger axis and the bottom of the concave portion is the base material trough radius r2. When the thickness of the nonmagnetic coating is defined as nonmagnetic layer thickness A, the value of (r1−r2) / 2 + A is 40 μm or more and 80 μm or less.
Here, the value of (r1−r2) / 2 + A is an effective value of the thickness of the coating. If this effective value is 40 μm or more and 80 μm or less, the side force is strengthened while strengthening the magnetic attractive force in the axial direction. Can be suppressed. Therefore, if the base metal peak radius r1, base valley radius r2 and nonmagnetic layer thickness A are set so that the effective value is not less than 40 μm and not more than 80 μm, the magnetic attractive force in the axial direction is enhanced. Strengthening of side force can be suppressed.

  The electromagnetic valve of the best mode 1 includes a spool that functions as a valve body, a solenoid coil that generates a magnetic attractive force when energized, a plunger that displaces the spool in the axial direction by the magnetic attractive force, and a plunger And a support member that is slidably supported in the axial direction from the outer peripheral side. The outer peripheral surface of the plunger has convex and concave portions protruding radially outward and concave portions recessed radially inward in the axial direction to form an uneven shape, and the non-magnetic coating is formed on the uneven outer peripheral surface. Is formed.

  Further, according to this solenoid valve, the distance between the plunger shaft center and the top of the convex portion is the base metal peak radius r1, the distance between the plunger shaft center and the bottom of the concave portion is the base material trough radius r2, and nonmagnetic When the thickness of the coating is defined as the nonmagnetic layer thickness A, the value of (r1−r2) / 2 + A is 40 μm or more and 80 μm or less.

[Configuration of Example 1]
The structure of the solenoid valve 1 of Example 1 is demonstrated using FIG.
As shown in FIG. 1, the electromagnetic valve 1 includes a spool 2 that functions as a valve body by being displaced in the axial direction, a sleeve 3 that accommodates the spool 2 so as to be slidable in the axial direction, and magnetically attracted by energization. A solenoid coil 4 that generates a force; a plunger 5 that is displaced in the axial direction by a magnetic attraction force to displace the spool 2 in one axial direction; and a core stator 6 that slidably supports the plunger 5 in the axial direction. For example, a hydraulic circuit in an automatic transmission (not shown) is switched.

  The spool 2 has a plurality of large-diameter portions 9 that are in sliding contact with the sleeve 3, and together with the sleeve 3 forms an internal flow portion 10 through which hydraulic fluid flows. A restoring spring 11 that urges the spool 2 toward the other axial direction is attached to one axial end of the spool 2, and one end of the plunger 5 is in contact with the other axial end of the spool 2. As a result, the spool 2 is displaced to one side in the axial direction by a magnetic attraction force acting on the plunger 5 in the axial direction, and is biased by the restoring spring 11 along with the disappearance of the magnetic attraction force and displaced to the other side in the axial direction. .

  The solenoid coil 4 is resin-molded in a substantially cylindrical shape, and is insulated from the core stator 6 disposed on the inner peripheral side and the yoke 13 disposed on the outer peripheral side. The outer shell of the solenoid valve 1 is composed of a yoke 13 and a sleeve 3, and one end of the yoke 13 is caulked and fixed to the other end of the sleeve 3, so that the solenoid valve 1 is integrated.

  The plunger 5 is provided in a columnar shape and is slidably accommodated on the inner peripheral side of the core stator 6. The other end of the spool 2 is in contact with one end of the plunger 5. When the solenoid coil 4 is energized, the plunger 5 is displaced to the one side in the axial direction by the magnetic attracting force in the axial direction, and the spool 2 is displaced to the one side in the axial direction. When the energization of the solenoid coil 4 is stopped, the plunger 5 receives the urging force of the restoring spring 11 from the spool 2 due to the disappearance of the magnetic attractive force and is displaced to the other side in the axial direction.

  The core stator 6 is provided on one side of the support portion 15 as a support member that supports the plunger 5 so as to be slidable in the axial direction from the outer peripheral side, and the plunger 5 is axially moved by an axial magnetic attraction force. There is a suction part 16 that attracts to one side, and a magnetic delivery part 17 that is provided on the other side of the support part 15 and delivers magnetism to and from the yoke 13. In the suction part 16, the facing surface facing one end of the plunger 5 is covered with resin, so that direct contact between the suction part 16 and the plunger 5 is prevented.

[Features of Example 1]
Features of the solenoid valve 1 of the first embodiment will be described with reference to FIG.
According to the solenoid valve 1 of the first embodiment, the outer peripheral surface of the plunger 5 has, as shown in FIG. 2, convex portions 19 protruding radially outward and concave portions 20 recessed radially inward alternately in the axial direction. It is provided with a concavo-convex shape, and a nonmagnetic coating 21 is formed on the concavo-convex outer peripheral surface.

  The distance between the axis of the plunger 5 and the apex 23 of the convex portion 19 is the base metal peak radius r1, the distance between the axis of the plunger 5 and the bottom 24 of the concave portion 20 is the base trough radius r2, and the coating 21 When the thickness is defined as the nonmagnetic layer thickness A, the base material peak radius r1, base material trough radius r2, and nonmagnetic property are set so that the value of (r1−r2) / 2 + A is 40 μm or more and 80 μm or less. The layer thickness A is set.

For example, when the nonmagnetic layer thickness A is set to 10 μm, the base metal peak radius r1 and base trough radius r2 are set so that the value of r1-r2 is 60 μm to 140 μm.
The value of (r1−r2) / 2 + A is an effective value of the thickness of the coating 21 that substantially determines the magnetic attractive force (side force) acting in the radial direction between the plunger 5 and the support portion 15. is there. If this effective value is 40 μm or more and 80 μm or less, the side force can be prevented from being strengthened while strengthening the magnetic attractive force in the axial direction.

[Effect of Example 1]
According to the electromagnetic valve 1 of the first embodiment, the outer peripheral surface of the plunger 5 is provided with the convex portions 19 and the concave portions 20 alternately in the axial direction to form an uneven shape, and the non-magnetic film 21 is formed on the uneven outer peripheral surface. Is formed.
Thereby, the plunger 5 is supported by the support part 15 slidably by the top 23 of the convex part 19 facing the inner peripheral surface of the support part 15 through the coating 21, and the outer peripheral surface of the plunger 5 and the support part are supported. The clearance between the inner peripheral surface 15 and the inner peripheral surface 15 is larger than that in the conventional case at a portion other than the top 23 of the convex portion 19. For this reason, since the effective value of the clearance can be reduced without lowering the coaxiality between the plunger 5 and the support portion 15, the eccentricity of the plunger 5 hardly occurs even if the thickness of the coating 21 is reduced.
As described above, by providing the outer peripheral surface of the plunger 5 in an uneven shape to reduce the thickness of the coating 21, it is possible to prevent a decrease in production efficiency accompanying the formation of the coating 21.

The value of (r1−r2) / 2 + A using the base metal peak radius r1, the base trough radius r2 and the nonmagnetic layer thickness A as parameters is 40 μm or more and 80 μm or less.
Here, since the value of (r1−r2) / 2 + A is the effective value of the thickness of the coating 21 as described above, the base material peak radius r1 is set so that the effective value is 40 μm or more and 80 μm or less. If the base material trough radius r2 and the nonmagnetic layer thickness A are set, the strengthening of the side force can be suppressed while strengthening the magnetic attractive force in the axial direction.

It is sectional drawing which shows the whole structure of a solenoid valve (Example 1). (A) is sectional drawing of the plunger which shows the principal part of a solenoid valve, (b) is a principal part enlarged view which expands and shows the principal part of a solenoid valve (Example 1). It is sectional drawing of the plunger which shows the principal part of a solenoid valve (conventional example).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solenoid valve 2 Spool 4 Solenoid coil 5 Plunger 15 Support part (support member)
19 Convex part 20 Concave part 21 Coating 23 Top 24 Bottom

Claims (2)

A spool that functions as a disc,
A solenoid coil that generates a magnetic attraction when energized,
A plunger that is displaced in the axial direction by a magnetic attraction force to displace the spool;
In a solenoid valve comprising a support member that slidably supports the plunger in the axial direction from the outer peripheral side,
The outer peripheral surface of the plunger has an uneven shape in which convex portions protruding radially outward and concave portions recessed inward in the radial direction are alternately provided in the axial direction,
A solenoid valve characterized in that a nonmagnetic coating is formed on the outer peripheral surface of the irregular shape. The solenoid valve according to claim 1,
The distance between the shaft center of the plunger and the top of the convex portion is the base metal peak radius r1, the distance between the shaft center of the plunger and the bottom of the concave portion is the base material trough radius r2, and the thickness of the nonmagnetic coating When the thickness is defined as the nonmagnetic layer thickness A, the value of (r1−r2) / 2 + A is 40 μm or more and 80 μm or less.

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