Electromagnetic switch and related manufacturing method

Abstract

An electromagnetic switch and related manufacturing method are disclosed having an electromagnetic coil creating an electromagnet when energized, a stationary core associated with the electromagnetic coil and operative to be magnetized when the electromagnet is created, one set of stationary contacts disposed in areas away from the stationary core, and a plunger carrying thereon a movable contact and operative to move toward the stationary contacts to close the same when the stationary core is magnetized by the electromagnet. The stationary core includes a base section and a disc section assembled to the base section. The disc section includes a plurality of stacked thin plates, fixedly secured to each other by fixing means, which have through-openings extending to each other in a circumferential direction in communication with each other to form a coil takeout opening through which an end portion of the electromagnetic coil is extracted.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view, taken on line B-B of FIG. 2, showing a stationary core of an electromagnetic switch of a first embodiment according to the present invention.

FIG. 2 is a plan view of the stationary core shown in FIG. 1 as viewed from a base section forming part of the stationary core.

FIGS. 3A to 3C are schematic views showing a basic sequence of forming thin plates for use in a disc section forming part of the stationary core shown in FIGS. 1 and 2.

FIG. 4 is a plan view of the stationary core as viewed from the disc section.

FIG. 5 is a side view of the stationary core shown in FIG. 4.

FIG. 6 is a cross sectional view of the electromagnetic switch incorporating the stationary core shown in FIGS. 1 and 2 and FIGS. 4 and 5.

FIG. 7 is a circuit diagram of the electromagnetic switch shown in FIG. 6.

FIG. 8 is a cross sectional view, taken on line B-B of FIG. 9, showing a stationary core of an electromagnetic switch of a second embodiment according to the present invention.

FIG. 9 is a plan view of the stationary core shown in FIG. 8 as viewed from a base section forming part of the stationary core.

FIG. 10 is a cross sectional view showing a stationary core of an electromagnetic switch of a third embodiment according to the present invention.

FIG. 11 is a cross sectional view showing a stationary core of an electromagnetic switch of a fourth embodiment according to the present invention.

FIG. 12 is an exploded perspective view showing a stationary core of an electromagnetic switch of the related art.

Claims

1. An electromagnetic switch comprising: an electromagnetic coil creating an electromagnet when energized;a stationary core operative to be magnetized by the electromagnet created by the electromagnetic oil;stationary electrical contacts fixedly disposed in a position away from the stationary core; anda movable contact movable with a plunger attracted by the magnetized stationary core in a direction to close the stationary electrical contacts;the stationary core including a base section and a disc section, assembled to the base section, which is disposed in an area on one side of the electromagnetic coil and has a coil takeout opening through which an end portion of the electromagnetic coil is extracted; andthe disc section including a plurality of stacked thin plates, formed in the same shapes, which have through-openings extending in a thickness direction of the disc section, respectively, and aligned to communicate with each other to form the coil takeout opening, and fixing means associated with the stacked thin plates to fixedly secure stacked thin plates with each other under a circumstance where the through-openings are aligned with each other with respect to a circumferential direction of the disc section.

2. The electromagnetic switch according to claim 1, wherein: the end portion of the electromagnetic coil is extracted from the coil takeout opening of the disc section to one surface of the outermost layer of the stacked thin plates at a position remote from the electromagnetic coil and jointed to the one surface of the outermost layer of the stacked thin plates by one of welding and soldering; andwherein the disc section has a fixing portion, through which the plurality of stacked thin plates are fixed by the fixing means, which has a height substantially equal to a thickness of the disc section.

3. The electromagnetic switch according to claim 2, wherein: the end portion of the electromagnetic coil is jointed to the one surface of the outermost layer of the stacked thin plates by one of the welding and soldering at an area close proximity to the fixing portion.

4. The electromagnetic switch according to claim 1, wherein: the stacked thin plates of the disc section are fixed to each other by caulking.

5. A method of manufacturing an electromagnetic switch, the method comprising the steps of: preparing an electromagnetic coil creating an electromagnet when energized;preparing a stationary core to be placed in a position adjacent to the electromagnetic coil;fixedly mounting stationary electrical contacts in a position away from the stationary core; andmounting a movable contact on a plunger operative to be attracted by the stationary core, when the electromagnetic coil is energized, to move in a direction to close the stationary electrical contacts;the stationary core preparing step including the step of:preparing a base section associated with the electromagnetic coil;forming a plurality of thin plates having the same shapes and having through-openings, respectively;stacking the plurality of thin plates in a way to allow the through-openings to be aligned with each other with respect to a circumferential direction;caulking the stacked thin plates at a caulked portion in a lump to prepare a disc section;assembling the disc section and the base section into the stationary core; andextracting an end portion of the electromagnetic coil through the takeout opening.

6. The method of manufacturing the electromagnetic switch according to claim 5, wherein: the step of forming a plurality of thin plates includes the steps of:forming the thin plates by punching; andforming the caulked portion, to be caulked, by press forming.

7. A method of manufacturing an electromagnetic switch, the method comprising the steps of: preparing an electromagnetic coil creating an electromagnet when energized;preparing a stationary core to be placed in a position adjacent to the electromagnetic coil;fixedly mounting stationary electrical contacts in a position away from the stationary core; andmounting a movable contact on a plunger operative to be attracted by the stationary core, when the electromagnetic coil is energized, to move in a direction to close the stationary electrical contacts;the stationary core preparing step including the step of:preparing a base section associated with the electromagnetic coil;forming a plurality of thin plates having the same shapes and having through-openings, respectively;stacking the plurality of thin plates in a way to allow the through-openings to be aligned with each other with respect to a circumferential direction;caulking the stacked thin plates at a caulked portion one by one in a sequence to prepare a disc section;assembling the disc section and the base section into the stationary core; andextracting an end portion of the electromagnetic coil through the takeout opening.

8. The method of manufacturing the electromagnetic switch according to claim 7, wherein: the step of forming a plurality of thin plates includes the steps of:forming the thin plates by punching; andforming the caulked portion, to be caulked, by press forming.

9. An electromagnetic switch comprising: an electromagnetic coil creating an electromagnet when energized;a plunger movably disposed in the electromagnetic coil and having a shaft axially extending from one end of the plunger;a stationary core associated the electromagnetic coil and operative to be magnetized by the electromagnet created by the electromagnetic oil;stationary electrical contacts disposed in positions away from the stationary core; anda movable contact, carried on one end of the shaft, which is normally urged in a position to open the electrical contacts and movable in a direction to close the stationary electrical contacts when the stationary core is magnetized by the electromagnetic coil;the stationary core including a base section, and a disc section, assembled to the base section, which is disposed in an area on one side of the electromagnetic coil and has a coil takeout opening through which an end portion of the electromagnetic coil is extracted; andthe disc section including a plurality of stacked thin plates, formed in the same shapes, which have through-openings extending in a thickness direction of the disc section, respectively, and aligned to communicate with each other to form the coil takeout opening.

10. The electromagnetic switch according to claim 9, wherein: the stacked thin plates are fixedly secured to each other by caulking under a circumstance where the through-openings are aligned with each other with respect to a circumferential direction of the disc section in communication with each other.

11. The electromagnetic switch according to claim 9, wherein: the stacked thin plates are fixedly secured to each other by a positioning pin press fitted to the stacked thin plates under a circumstance where the through-openings are aligned with each other with respect to a circumferential direction of the disc section in communication with each other.

12. The electromagnetic switch according to claim 9, wherein: the stacked thin plates are fixedly secured to each other by a rivet inserted to the stacked thin plates under a circumstance where the through-openings are aligned with each other with respect to a circumferential direction of the disc section in communication with each other.

13. The electromagnetic switch according to claim 9, wherein: the stacked thin plates are fixedly secured to each other by a spring pin inserted to the stacked thin plates under a circumstance where the through-openings are aligned with each other with respect to a circumferential direction of the disc section in communication with each other.

14. The electromagnetic switch according to claim 9, wherein: the end portion of the electromagnetic coil is extracted from the coil takeout opening of the disc section to one surface of the outermost layer of the stacked thin plates at a position remote from the electromagnetic coil and jointed to the one surface of the outermost layer of the stacked thin plates by one of welding and soldering; andwherein the disc section has a fixing portion, through which the plurality of stacked thin plates are fixed by the fixing means, which has a height substantially equal to a thickness of the disc section.

15. The electromagnetic switch according to claim 14, wherein: the end portion of the electromagnetic coil is jointed to the one surface of the outermost layer of the stacked thin plates by one of welding and soldering at an area close proximity to the fixing portion.