WO2000063937A1

WO2000063937A1 - Electromagnetic relay and method of making the same

Info

Publication number: WO2000063937A1
Application number: PCT/EP2000/003421
Authority: WO
Inventors: Ralf Hoffmann; Heinz Stadler
Original assignee: Tyco Electronics Logistics AG
Current assignee: TE Connectivity Solutions GmbH
Priority date: 1999-04-16
Filing date: 2000-04-14
Publication date: 2000-10-26
Anticipated expiration: 2001-10-16
Also published as: DE19917338C2; DE19917338A1

Abstract

The invention relates to an electromagnetic relay adapted for universal application. The relay comprises an assembly of a base member (17), an electromagnetic system (16), an armature (5), a contact system (7), terminal conductors (11), a switching chamber (18) and a casing (15), with the switching chamber (18) being closed by a covering cap (12) and the casing being constituted by embedding said stationary parts of the electromagnetic system (16) and the covering cap (12) in insulating material.

Description

Specification

Electromagnetic Relay and Method of Making the Same

The invention relates to an electromagnetic relay com- prising the following features: a base member which carries an electromagnetic system including a coil, a core assembly and an armature and constitutes part of a switching chamber, a contact system arranged in the switching chamber and having at least one fixed contact and one movable contact spring carrying a switching contact and adapted to be actuated by said armature, terminal conductors for the contacts and for the coil, - a casing enclosing the electromagnetic system and the switching chamber.

In addition thereto, the invention relates to a method of making such a relay.

Relays usually are constructed in such a manner that a header, constituting a casing bottom, has the various components of the relay mounted thereon, and finally a casing cap is slid over the arrangement so that a closed casing results. With relays of such construction the coil winding and the contact system are spatially interconnected so that contact-damaging outgassing from the coil may impair the contact surfaces. While certain contact coatings may be burnt away by the switching current in case of power relays, this does not hold for miniature relays for switching small currents. It is thus desirable to spatially separate the coil region from the contact system region and to avoid outgassing from the coil, respectively.

DE 196 26 982 Cl already discloses a relay in which the coil winding is cast in casting resin so that outgassing from the coil winding cannot arise. However, in case of said arrangement, there is no optimum acoustic encapsulation of the relay, since the movable parts which cause noise are not separated from the surroundings by a thick casting resin layer, but by a comparatively thin casing wall .

It is the object of the invention to make available a relay of the type indicated at the outset which prevents contact damage by outgassing from the coil and is provided with a good acoustic encapsulation, without this entailing a complex construction.

According to the invention, this object is met in that the switching chamber is closed by a covering cap and in that the casing is constituted by shape-defining embedding of the stationary parts of the electromagnetic system and by at least partial embedding of the base member and the covering cap in insulating material, with the terminal conductors being passed to the outside through a casing wall.

The relay according to the invention meets the object in particularly advantageous manner since no additional parts need be employed for noise encapsulation. Partial molding or casting is usual anyway due to the winding outgassing, so that no additional expenditure arises and assembly is facilitated.

A method of making a relay according to the invention consists in that the switching chamber is sealed towards the outside by a covering cap before the stationary parts of the electromagnetic system, the covering cap and the base member are embedded in plastics material in part or completely. The relay is designed in particular- ly advantageous manner when the covering cap cooperates with the base member. The base member fixing the relay components during assembly thus also fulfils the function of a sealing wall.

A simple development of the relay according to the invention also results from the fact that no stable header has to be provided as in conventional relays, but that the necessary mechanical stability is achieved according to the invention by embedding in plastics material. The high stability is significant as the often low air gap and contact spacings are sensitive to distortion of the system. Moreover, the embedding provides for a favorable temperature behavior.

An additional advantage results from the fact that no interfering particles are formed during assembly, as it happens otherwise in the assembly of relay components in a casing.

In addition to the advantages already indicated hereinbefore, a relay according to the invention minimizes the number of parts and thus also the assembly costs.

Further details and developments of the invention are indicated in the dependent claims . The invention will be elucidated in more detail hereinafter by way of an embodiment with reference to the drawings in which:

Figs. 1A to C show schematic representations of a relay according to the invention and the assembly thereof,

Figs. 2A to D show a relay according to the invention in a concrete embodiment.

Figs, la to c schematically illustrate the manufacturing steps for making a relay according to the invention. Initially, there are preassembled an electromagnetic system consisting of a coil 1, a core assembly 4 and an armature 5 with a resetting spring 6, as well as a contact system 7 consisting of a contact spring 10 connected to armature 5, of two fixed contacts 8 and a switching contact 9 that is mounted to contact spring 10. On the side of electromagnetic system 7 having armature 5 mounted thereon, there is formed a switching chamber 18. In the latter, there is also provided contact system 7. In a second step, switching chamber 18 is closed by a covering cap 12. Cap 12 positively abuts a yoke of core assembly 4, a sealing-wall -establishing extension 13 of a coil body flange 14 and laterally, not shown in the drawings, abuts coil body flange 14, such that the arrangement with contacts 8 and 9, contact spring 10, armature 5 and resetting spring 6 is sealed completely to- wards the outside (Fig. IB) .

Extension 13 is designed mechanically such that it is adapted to fix contacts 8 and 9 as well as terminal conductor 11 thereof, respectively, but does not offer sta- bility therebeyond. It is also conceivable to have an arrangement in which extension 13 serves only for sealing switching chamber 18.

In the last manufacturing step (Fig. 1C) , the assembly of electromagnetic system 16, contact system 7 and covering cap 18 has plastics material molded therearound, so that the molding forms a casing 15, with the exterior ends of terminal conductors 11 being left free. Molding 15 effects the firm connection of all relay parts and takes up the forces acting in particular on the terminal conductors 11 of the relay. In addition thereto, it effects acoustic encapsulation of the relay. In particular in applications in which the acoustic behavior does not play a predominant role, covering cap 12 may constitute a part of the casing that has no plastics material molded therearound. The other advantages provided by the construction according to the invention are maintained.

Figs. 2A to 2D reveal the construction of a relay according to the invention in a concrete embodiment as well as the assembly thereof. At first, the relay is preassembled in known manner, with the design of an armature and a contact system being of subordinate signif- icance for a relay according to the invention, and these parts being thus not shown here, either. Fig. 2A basically shows such a relay in a perspective view. The movable parts are mounted on an extension 33 of coil body flange 34 and on a mounting header 36 molded onto coil body flange 34 and extension 33.

After assembly of the relay system, a covering cap 32 formed of plastics material according to Fig. 2B is applied. According to Fig. 2C, said covering cap 32 is applied over the movable parts of the relay in such a manner that it positively abuts extension 33 and coil body flange 34 and constitutes a closed switching chamber together with the same. By applying the molding material 35 in a last manufacturing step, the relay according to Fig. 2D is formed that is completely encapsulated except for terminal conductors 31.

Claims

Patent Claims

1. An electromagnetic relay comprising the following features : a base member (17; 37) which carries an electromagnetic system (16) including a coil (1; 21), a core assembly (4; 24) and an armature (5) and constitutes part of a switching chamber (18) , a contact system (7) arranged in the switching chamber (18) and having at least one fixed contact (8) and one movable contact spring (10) carrying a switching contact (9) and adapted to be actuated by said armature (5) , terminal conductors (11; 31) for the contacts (8, 9) and for the coil (1; 21), and a casing (15; 35) enclosing the electromagnetic system (16) and the switching chamber (18) , characterized in that the switching chamber (18) is closed by a covering cap (12; 32) , and in that the casing (15; 35) is constituted by shape- defining embedding of the stationary parts of the electromagnetic system (16) and by at least partial embedding of the base member (17; 37) and the covering cap (12; 32) in insulating material, with the terminal conductors (11; 31) being passed to the outside through a casing wall .

2. The relay of claim 1, characterized in that the base member (17; 37) is formed as coil body (2) and in that the switching chamber (18) is formed by an extension (13; 33) of a coil body flange (14; 34) .

3. The electromagnetic relay of claim 1 or 2 , characterized in that the mechanic stability of the relay is created by the casing (15; 35) formed by said embedding in insulating material .

4. A method of making a relay according to any of claims 1 to 3 , characterized in that the switching chamber (18) is sealed towards the outside by a covering cap (12; 32) before the stationary parts of the electromagnetic system (16), the covering cap (12; 32) and the base member (17; 37) are embedded in plastics material completely or in part.