The present invention relates to an electromagnetic relay, in particular to an attachment structure of its movable block.
In the past, for example, there has been an electromagnetic relay in which, of a pair of hinge portions protruded from both sides of a movable block on a same axis, wide connection portions are welded so as to be integrated with common contact terminals of a base block to provide welded portions, and based on excitation and non-excitation of an electromagnetic block mounted on the base block, the movable block is rotated, with shaft portions of the hinge portions as a rotation axis to open and close contacts (refer to Patent Document 1).
However, in the above electromagnetic relay, the connection portions forming the hinge portions are merely connected so as to be integrated with the common contact terminals. Therefore, if the movable block is rotated based on excitation and non-excitation of the electromagnetic block, a stress whose point of action is at a basal portion of a shaft portion, which forms a hinge portion, is concentrated at end portions of a boundary between a connection portion and a welded portion, so that cracks are liable to occur at the hinge portion.
One or more embodiments of the present invention provides an electromagnetic relay in which cracks hardly occur and which has a much longer life.
In an electromagnetic relay according to one or more embodiments of the present invention, of a pair of hinge portions protruded from both sides of a movable block on a same axis, wide connection portions are welded so as to be integrated with common contact terminals of a base block to provide welded portions, and based on excitation and non-excitation of an electromagnetic block mounted on the base block, the movable block is rotated, with shaft portions of the hinge portions as the rotation axis to open and close contacts,
a reference line connecting a point of action, which is located between a welded portion provided in an inside edge portion of a connection portion of a hinge portion and the rotation axis, and a center of a welded portion intersects a boundary between the connection portion and the welded portion, which are welded so as to be integrated.
According to one or more embodiments of the present invention, since an internal stress generated from the point of action, which is located at the basal portion of the shaft portion forming the hinge portion, dispersedly acts on the boundary between the connection portion and the welded portion, a stress concentration does not occur. Therefore, cracks hardly occur, and an electromagnetic relay having a much longer life is obtained.
In an embodiment of the present invention, a bottom portion of a cutout portion provided in the inside edge portion of the connection portion of the hinge portion is welded so as to be integrated with a common contact terminal of the base block to provide the welded portion.
According to the present embodiment, the boundary between the connection portion and the welded portion becomes longer, so that a retention force obtained by welding is improved, and an electromagnetic relay having a much longer life is obtained.
In an embodiment of the present invention, the hinge portion may have a roughly T-shape in plan view or a roughly L-shape in plan view.
According to the present embodiment, the hinge shape can be selected as necessary, and there is an effect that a versatile electromagnetic relay is obtained.
In embodiments of the invention, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid obscuring the invention.
An embodiment of the present invention will be described with reference to the attached drawings of
An electromagnetic relay of the present embodiment consists of a base block 20 in which an electromagnetic block 10 is insert-molded, a movable block 40, and a case 60 as shown in
As shown in
The base block 20 is manufactured by insert molding the electromagnetic block 10 connected to the lead frame not shown in the base block 20, followed by press working. As shown in
In the electromagnetic block 40, as shown in
The movable iron piece 41 is covered by the movable block body 45 excluding both-side end portions 41a, 41b, and by cutting a corner portion of the one end portion 41b, the assembling direction is indicated.
Both-side end portions of the movable contact piece 43, which are bifurcated in a width direction, are provided with movable contacts 43a, 43b to provide a twin-contact structure, whereby contact reliability is improved. Further, a roughly T-shaped hinge portion 50 is coplanarly extended from a central portion of one side of the movable contact piece 43a. As shown in
The movable contact piece 44 has a shape that is line symmetrical with the movable contact piece 43, and both end portions thereof are provided with movable contacts 44a, 44b. Regarding the hinge portion 50, its description is omitted by giving the same numerals.
The movable block body 45 covers the movable iron piece 41 excluding the both-end portions 41a, 41b thereof, and a bottom surface of the movable contact block body 45 is provided with positioning recesses 45a, 45a fitted to the protrusions 21, 21 of the base block 20.
Then, the positioning recesses 45a, 45a of the movable block 40 are fitted to the protrusions 21, 21 of the base block 20 so as to be positioned, and the connection portions 52 of the hinge portions 50 are positioned with respect to the contact portions 30a, 31a of the common contact terminals 30, 31 exposed from the base block 20. Thereafter, the bottom portions of the second cutout portions 54 are irradiated with a laser, and the connection portions 52 and the connection receiving portions 30a, 31a are welded so as to be integrated to form welded portions, whereby the movable block 40 is rotatably supported around an axis of the shaft portions 51.
Subsequently, the case cover 60 is put on the base block 20, with which the movable block 40 is integrated, and sealed. After sucking and removing an internal gas from a degassing opening in the case cover 60, the degassing opening is thermally sealed, and an assembling work is completed.
Next, an operation of the electromagnetic relay will be described.
When the electromagnetic block 10 is in a non-excited state, one end portion 41a of the movable iron piece 41 is attracted to the magnetic pole portion 14a of the iron core 14 by a magnetic force of the permanent magnet 42, and the movable contacts 43a, 44a are in contact with the fixed contacts 32a, 33a, respectively.
If the coil 15 of the electromagnetic block 10 is excited by applying a voltage so that a magnetic flux is generated in a direction in which the magnetic force of the permanent magnet 42 is canceled, the magnetic pole portion 14b of the iron core 14 attracts the other end portion 41b of the movable iron piece 41, and the movable block 40 is rotated against the magnetic force of the permanent magnet 42. Therefore, the movable contacts 43a, 44a are separated from the fixed contacts 32a, 33a, the movable contacts 43b, 44b come in contact with the fixed contacts 34a, 35b, and then the other end portion 41b of the movable iron piece 41 is attracted to the other end portion 14b of the iron core 14.
If the voltage application to the magnetic block 10 is stopped, the movable block 40 is rotated in the opposite direction of the above based on the magnetic force of the permanent magnet 42, and the torsion moment of the shaft portions 51 of the hinge portions 50, and returned to the original position.
In the electromagnetic relay of the above embodiment, as shown in
As shown in
As is apparent from
This is considered as follows. The position of the bottom portion of the first cutout portion 53 is located deeper than the position of the bottom portion of the second cutout portion 54, and the bottom portion of the second cutout portion is welded so as to be integrated with the connection receiving portion 30a of the common contact terminal 30, so that the boundary between the welded portion 59 and the connection portion 52 is long. Therefore, a stress generated in the shaft portion 51 is dispersedly loaded from the point 58 of action to the periphery of the welded portion 59 of the second cutout portion 54.
As a result, according to the present embodiment, it is considered that the mechanical durability at the welded portion 59 is improved by 100 times or more if converted based on the S-N curve.
The present invention may be applied not only to an electromagnetic relay having a movable block provided with a hinge portion having a roughly T-shape in plan view, but also to an electromagnetic relay having a movable block provided with a hinge portion having a roughly L-shape in plan view.
While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.
Number | Date | Country | Kind |
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2007-115831 | Apr 2007 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2008/057499 | 4/17/2008 | WO | 00 | 10/22/2009 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2008/133174 | 11/6/2008 | WO | A |
Number | Name | Date | Kind |
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5015978 | Yokoo et al. | May 1991 | A |
5309623 | Okamoto et al. | May 1994 | A |
5617066 | Dittmann et al. | Apr 1997 | A |
Number | Date | Country |
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61-218025 | Sep 1986 | JP |
9-259726 | Oct 1997 | JP |
9-288954 | Nov 1997 | JP |
Number | Date | Country | |
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20100117771 A1 | May 2010 | US |