Solenoid having a barrier between a solenoid housing and package

Abstract

A solenoid is provided that includes: a primary package that is made of a molding resin and covers a solenoid body in which a coil is wound around a bobbin; and a secondary package that is made of a molding resin and covers the primary package. A contact surface between the primary package and the secondary package is provided with an anchor shape for enhancing joint strength between the primary package and the secondary package. The solenoid includes a connector part for electrifying the coil in addition to the solenoid body, the primary package covers both the solenoid body and the connector part, and the secondary package covers only a part of the primary package covering the solenoid body.

Claims

1. A solenoid comprising: a housing including a solenoid body in which a coil is wound around a bobbin, the housing including at least a section that is cylindrical; a primary package at least partially received within the section of the housing that is cylindrical, a portion of the primary package that is at least partially received within the section of the housing being radially spaced apart from the section of the housing by a first gap, and a flange of the primary package that extends radially outward from the portion is axially spaced apart from the section of the housing by a second gap that communicates with the first gap; and a secondary package that is made of a molding resin, covers the primary package, and is received within at least the second gap and configured to block entry of foreign matter into the housing, wherein the solenoid includes a connector part for electrifying the coil in addition to the solenoid body, the primary package covers both the solenoid body and the connector part, and the secondary package covers only a part of the primary package covering the solenoid body.

2. The solenoid according to claim 1, wherein a contact surface between the primary package and the secondary package is contoured to anchor the primary package to the secondary package.

3. The solenoid according to claim 1, wherein the primary package includes a plurality of apertures, and the molding resin of the secondary package is located in the apertures to secure the secondary package to the primary package.

4. The solenoid according to claim 2, wherein the primary package includes a plurality of apertures, and the molding resin of the secondary package is located in the apertures to secure the secondary package to the primary package.

5. The solenoid according to claim 1, wherein the primary package is formed of a resin.

Description

BRIEF EXPLANATION OF THE DRAWINGS

(1) FIG. 1 is a cross-sectional view illustrating a state in which a housing is equipped with a solenoid according to a first embodiment of the present invention.

(2) FIG. 2 is a cross-sectional view illustrating a state in which a housing is equipped with a solenoid according to a second embodiment of the present invention.

(3) FIG. 3 is an enlarged cross-sectional view illustrating a main portion of the solenoid.

(4) FIGS. 4A and 4B are views illustrating a solenoid according to a third embodiment of the present invention, where FIG. 4A shows a plan view and a front view illustrating a state after covering with a primary package and before covering with a secondary package, and FIG. 4B shows a plan view and a front view illustrating a state after the covering with the primary package and covering with the secondary package.

(5) FIGS. 5A to 5C are enlarged plan views of an anchor shape included in the solenoid.

(6) FIG. 6 is a cross-sectional view of a solenoid according to a conventional example.

(7) FIG. 7 is a cross-sectional view illustrating a state in which a housing is equipped with a solenoid according to a comparative example.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(8) Embodiments of the present invention will be described hereinafter, and for convenience of description, a solenoid 1 according to a comparative example will be first described.

Comparative Example

(9) Specifically, FIG. 7 illustrates a state in which the solenoid 1 according to the comparative example is attached to an opening portion of the upper end of a cylindrical housing 41 together with a valve operating part 31.

(10) The solenoid 1 according to the comparative example includes: a solenoid body 2 including an electromagnetic coil 3, a bobbin 4, a yoke 5, a fixed iron core 6, and so forth; and a connector part 7 for electrifying the coil 3. These components are covered (formed by molding) with a primary package 11 of a predetermined molding resin. Thus, the primary package 11 integrally includes a disc-shaped (turned-down-cup-shaped) first covering portion 12 covering the outer peripheral surface and the upper surface of the solenoid body 2, and a flange-shaped second covering portion 13 covering the connector part 7 with the lower surface of the connector part 7 exposed.

(11) When the solenoid 1 is attached to the opening portion of the upper end of the cylindrical housing 41 together with the valve operating part 31 including a movable iron core 32, a valve shaft 33, a valve body 34, and so forth, the illustrated state is obtained. At this time, a gap c is formed between the primary package 11 and the upper end of the housing 41. Accordingly, external foreign matter (not shown) might enter the gap c (indicated by arrow d) to cause a failure in operation of the solenoid 1. In view of this, a solenoid 1 according to an embodiment of the present invention additionally has the following configuration.

First Embodiment

(12) Specifically, as illustrated in FIG. 1, the primary package 11 covering the solenoid body 2 including the electromagnetic coil 3, the bobbin 4, and so forth is further covered with a secondary package 21, and this secondary package 21 closes the gap c between the primary package 11 and the top portion of the housing 41.

(13) The secondary package 21 is molded by using a predetermined molding resin. The secondary package 21 covers not the entire primary package 11 but a part of the primary package 11, specifically, covers only an outer peripheral edge portion of the disc-shaped first covering portion 12 in the primary package 11 to form a canopy shape for the first covering portion 12.

(14) Materials for the primary package 11 and the secondary package 21 are of the same type, but may be of different types in some operating conditions and environments.

(15) Since the solenoid 1 having the foregoing configuration includes the secondary package 21 that further covers the primary package 11 covering the solenoid body 2, the gap c between the primary package 11 and the upper end of the housing 41 can be closed by the secondary package 21. Accordingly, entering of external foreign matter through the gap c between the primary package 11 and the housing 41 can be suppressed so that occurrence of a failure in operation of the solenoid 1 due to entry of the foreign matter can be thereby reduced.

Second Embodiment

(16) In a solenoid 1 illustrated in FIG. 2 as a second embodiment, a contact surface between the primary package 11 and the secondary package 21 is provided with an anchor shape 8 for enhancing joint strength between these packages, in addition to the configuration according to the first embodiment. The anchor shape 8 is configured in the following manner.

(17) That is, as illustrated in FIG. 3 in an enlarged manner, a flange portion 14 covered with the secondary package 21 is integrally provided on the outer peripheral surface of the disc-shaped first covering portion 12 in the primary package 11, and the flange portion 14 has a plurality of through holes 15 arranged along the circumference so that the through holes 15 are filled with a part of the molding resin constituting secondary package 21, and thereby, the flange portion 14 serves as a pull-out stopper.

(18) Accordingly, with this configuration, since the contact surface between the primary package 11 and the secondary package 21 is provided with the anchor shape 8 for enhancing joint strength between these packages, it is possible to prevent the secondary package 21 from falling off to be detached from the primary package 11.

Third Embodiment

(19) The anchor shape 8 may take various possible shapes, and may have the following shape, for example.

(20) In a solenoid 1 illustrated in FIGS. 4A and 4B as a third embodiment, the contact surface between the primary package 11 and the secondary package 21 is provided with the anchor shape 8 for enhancing joint strength between these packages, in addition to the configuration according to the first embodiment. The anchor shape 8 is configured in the following manner.

(21) Specifically, as illustrated in the plan view of FIG. 4A, the upper surface of the outer peripheral edge portion of the disc-shaped first covering portion 12 in the primary package 11 has a plurality of (five in the Figure) bottomed holes 16 arranged along the circumference, and each of the holes 16 is filled with a part the molding resin constituting the secondary package 21 (not shown) so that the holes 16 serve as pull-out stoppers.

(22) Accordingly, with this configuration, since the contact surface between the primary package 11 and the secondary package 21 is provided with the anchor shape 8 for enhancing joint strength between these packages, it is possible to prevent the secondary package 21 from falling off to be detached from the primary package 11.

(23) The planar shape of each hole 16 is not limited to a specific shape, and may be an arc shape as illustrated in FIG. 5A or a circular shape as illustrated in FIG. 5B, for example.

(24) The holes 16 may be open at both the upper surface and the side surface (peripheral surface) of the primary package 11. In this case, the joint strength is further increased. FIG. 5C illustrates an example in this case, where the planar shape of each hole 16 is a T shape, and the tip of the vertical line of the “T” is also open at the side surface (outer circumferential surface) of the primary package 11.