Small sized electromagnetic relay

Abstract: In an electromagnetic relay, the position of an electromagnet assembly (X) having a core (4), a bobbin (1), a yoke (5), a hinge spring (6), and an armature (7) relative to a base block assembly (Y) having a base block (8) and a contact spring assembly (9, 10, 11) is adjustable to maintain a desired contact follow and compensate for variation of elements during assembly.

Description: The present invention relates to an electromagnetic relay used in an industrial apparatus, an automobile, and the like. In general, an electromagnetic relay is constructed by a core, a bobbin into which the core is inserted, a winding wound on the bobbin, a yoke fixed to an end of the core, an armature coupled via a hinge spring to the yoke, and coupled to the other end of the core, a movable contact, a stationary contact, a base block for adhering the contacts thereto, and the like. An electromagnetic assembly including the core, the bobbin, the winding, the yoke, the armature, and the like is located at a predetermined position with the base block. Such a relay is described in EP-A-0161473. In this case, after these elements are assembled, a relationship therebetween is determined to thereby obtain a load of the armature, and thus establish a sufficient contact pressure between the movable contact and the stationary contact in an active mode. Similarly, EP-A-0322181 representing the closest prior art discloses an electromagnetic relay according to the opening portion of claim 1. Nevertheless, in practice the dimensions, strength and the like of the elements of the relay fluctuate, and therefore, a contact gap between the movable contact and the stationary contact and an armature load characteristic also fluctuate in accordance with the electromagnetic relay. As a result, the contact gap and the armature characteristic are designed by taking into consideration the fluctuations of each of the elements. Therefore, in the above-mentioned prior art, since an absorption force (coercive force) of an electromagnet must be designed to satisfy a maximum armature load characteristic, the size of the electromagnet, i.e., the size of the relay, is increased, and as a result, a power dissipation must be increased to cope with the increased size of the relay. Therefore, an object of the present invention is to provide an electromagnetic relay having a small size and a low power dissipation. A relay according to the present invention is characterised by the features set out in the characterising portion of claim 1. The present invention will be more clearly understood from the following description, by way of example, with reference to the accompanying drawings, wherein: Fig. 1 is an exploded, perspective view illustrating an embodiment of the electromagnetic relay according to the present invention; Fig. 2 is a longitudinal cross-sectional view of the assembled relay of Fig. 1; Fig. 3 is a transverse cross-sectional view of the assembled relay of Fig. 1; Fig. 4 is a perspective view of the winding terminal of Fig. 1;

Claims: An electromagnetic relay comprising: an electromagnet assembly (X) having a core (4), a bobbin (1) for inserting said core thereinto, a yoke (5) fixed to an end of said core, and an armature (7) coupled to the other end of said core; a hinge spring (6) for the armature; and a base block assembly (Y) having a base block (8) and a contact spring assembly (9, 10, 11) including a movable contact (9a) and a stationary contact (10a, 11a) adhered to said base block, characterised in that said armature (7) is coupled via said hinge spring (6) to said yoke (5), said armature is adjustably mounted relative to said contact spring assembly (9, 10, 11) by adjustable mounting of said electromagnet assembly (X) relative to said base block assembly (Y) and the adjusted position of said electromagnet assembly (X) is fixable relative to said base block (8). A relay as set forth in claim 1, wherein said armature is arranged on the side opposite to said contact spring assembly with respect to said core, and sloped portions (8d, 8e) are formed on said base block along said winding, said relay further comprising a card (12) having two parallel arms (12e, 12f) for coupling said movable contact to said armature, said parallel arms being arranged on said sloped portions (8d, 8e) of said base block. A relay as set forth in claim 2, wherein protrusions (8f, 8f', 8g, 8g') are provided at said sloped portions of said base block, to thereby define the positions of said parallel arms. A relay as set forth in any of claims 1 to 3, wherein said electromagnet assembly further comprises two winding terminals (3a, 3b) inserted under pressure into said bobbin, each of said winding terminals comprising a first squeeze (31) by which said winding terminals are retained in a provisional position in which ends (2a, 2b) of said winding are twisted on said winding terminals, and a second squeeze (32) by which said winding terminals are retained in a permanent position. A relay as set forth in claim 4, wherein the distance (ℓ 1 ) between a winding groove (1e) of said bobbin and a twisting starting point of the end of said winding at the provisional position defined by said first squeeze of said winding terminal is approximately the same as the distance (ℓ 2 ) between the winding groove of said bobbin and a twisting starting point of the end of said winding at the permanent position defined by said second squeeze of said winding terminal. A relay as set forth in claim 4 or 5, wherein a soldering operation is performed upon said twisted ends of said winding terminals except for one or two turns thereof. An electromagnetic relay as set forth in any preceding claim, wherein a gap (A) between the top of said core (4) and an end portion of said bobbin (1) enables the bobbin to be moved relative to the core (4).

Inventors: ICHIKAWA TOMOHISA, KOBAYASHI ATSUTO, NAKABAYASHI TAKAHIRO, OZAWA HISAO, SHIBUSAWA TAKESHI, TOMONO NOBORU, ICHIKAWA, TOMOHISA, KOBAYASHI, ATSUTO, NAKABAYASHI, TAKAHIRO, OZAWA, HISAO, SHIBUSAWA, TAKESHI, TOMONO, NOBORU
Applicants: TAKAMISAWA ELECTRIC CO, TAKAMISAWA ELECTRIC CO., LTD.
Application year: 1991
Main classification: H01H50
IPC codes: H01H49, H01H50