JP2010182842A - Ignition coil for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition coil for an internal combustion engine at low cost, for certainly grounding an iron core by a simple configuration and effective in reduction of noise. <P>SOLUTION: The ignition coil for an internal combustion engine includes: a primary coil and a secondary coil; an iron core 12 for magnetically coupling the primary coil and the secondary coil; an insulating case 13 for containing the coils and the iron core; and a ground terminal 11' of a connector socket 11 electrically connected to a ground side of a power transistor 19a included in an ignitor 19 from an external harness. In the ignition coil for an internal combustion engine, an end portion 11'a of the ground terminal 11' of the connector socket 11 is arranged close to a bottom portion 12a of the iron core 12 such that the ground terminal 11' of the connector socket 11 and the iron core 12 are electrically coupled, and conductive rubber 10 for stress relaxation is interposed between the ground terminal 11' of the connector socket 11 and the bottom portion 12a of the iron core 12 so as to ground the iron core 12. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ignition coil for an internal combustion engine, for example, an internal combustion engine, which is attached to an engine of an automobile and supplies a high voltage for generating a spark discharge to a spark plug provided at the bottom of the plug hole of the engine.

  Conventional ignition coils for internal combustion engines are generally configured as shown in FIG. 2 (a) to 2 (c) are diagrams for explaining an ignition coil for an internal combustion engine in a conventional example. (A) is a longitudinal sectional view, (b) is a plan view, and (c) is (b). It is BB 'sectional drawing of). In FIG. 2, the insulating case 23 of the internal combustion engine ignition coil includes, for example, a connector socket 21, a fixing flange 25 provided on the opposite side of the connector socket 21, and the connector socket 21. And at least a storage part such as a coil assembly. The coil assembly storage portion stores a coil assembly 22 ′ including a coil and an iron core 22, and an igniter 29 including a power transistor and the like, and is filled with a filler 28.

  A mounting hole 26 is formed in the fixing flange 25, and, for example, a metal bush 26 'is formed therein. A conductive metal film 24 is formed on the upper surface of the fixing flange 25 as shown in the figure. The conductive metal film 24 is formed by a known method and is formed so as to be exposed on the inner peripheral surface of the insulating case 23. The iron core 22 in the coil assembly storage portion is in contact with and electrically connected to the conductive metal film 24. The coil-side ground terminal 21 ′ in the connector socket 21 opposite to the conductive metal film 24 is in contact with and electrically connected to the iron core 22 in the coil assembly storage portion.

  Furthermore, the fixing flange 25 is fixed to a part of an engine (not shown) with a bolt, for example. The coil-side ground terminal 21 'is electrically connected to the engine side via a conductive metal film 24', an iron core 22, a conductive metal film 24, a bolt (not shown), and a metal bush 26 '. The iron core 22 is grounded by a ground terminal 21 'or an engine (not shown) by a conductive metal film 24 and a conductive metal film 24'. For this reason, the noise radiated | emitted from a coil can be reduced. An example of an ignition coil for an internal combustion engine having such a configuration is described in Patent Document 1.

JP 2007-180295 A

  However, in conventional ignition coils for internal combustion engines, in order to ground the iron core to the engine or the like, a conductive metal film is provided on the inner wall of the insulating case, and the conductive metal film and the iron core are brought into contact with each other. The iron core was grounded to the engine.

  For this reason, the conductive metal film has to be bent in accordance with the outer shape of the iron core. Further, in order to maintain good contact with the iron core, the conductive metal film is bent to give spring properties. Therefore, it takes time to bend and form one of the causes of high costs.

  Further, if the shape of the conductive metal film and the shape of the iron core do not exactly match, a contact failure may occur and the electrical connection may be broken.

  The present invention has been made in view of the above, and it is an object of the present invention to provide an ignition coil for an internal combustion engine that can reliably ground an iron core with a simple configuration and is effective in reducing noise at a low cost. .

  The invention according to claim 1 is a power provided in an igniter from a primary coil and a secondary coil, an iron core that magnetically couples the primary coil and the secondary coil, an insulating case that houses the coil and the iron core, and an external harness. An internal combustion engine ignition coil comprising a connector socket ground terminal electrically connected to a ground side of a transistor, wherein the connector socket ground terminal is electrically connected to the iron core. A terminal is disposed close to the iron core, and a conductive rubber for stress relaxation is interposed between the ground terminal of the connector socket and the bottom of the iron core to ground the iron core. And

  The invention according to claim 2 is the ignition coil for an internal combustion engine according to claim 1, wherein the conductive rubber is a conductive adhesive.

  In the ignition coil for an internal combustion engine of the present invention, since conductive rubber is interposed between the ground terminal of the connector socket and the iron core, the electrical connection between the ground terminal of the connector socket and the iron core is made. Can be easily obtained. That is, the iron core can be reliably grounded to the engine or the like via the ground terminal of the connector socket. Therefore, the noise can be effectively reduced by grounding the iron core, and the noise prevention resistor can be omitted. In addition, the conductive rubber provides continuity between the iron core and the ground terminal of the connector socket, so no mechanical processing such as welding or caulking is required between the iron core and the ground terminal, making it extremely easy to assemble. Can do.

1 is a schematic explanatory view with a part omitted showing an ignition coil for an internal combustion engine according to the present invention. The outline of the conventional ignition coil for internal combustion engines is shown, (A) is a longitudinal cross-sectional view, (B) is a plan view, and (C) is a BB 'cross-sectional view of (B).

  FIG. 1 is a view for explaining an ignition coil for an internal combustion engine according to an embodiment of the present invention, and is a schematic explanatory view with a part omitted.

  In FIG. 1, an insulating case 13 for an internal combustion engine ignition coil includes, for example, a connector socket 11, a fixing flange 15 provided on the opposite side of the connector socket 11, and the connector socket 11 and the fixing flange 15. And at least a storage part such as a coil assembly formed between them. In the storage section for the coil assembly or the like, a coil assembly 12 'including a coil and an iron core 12, and an igniter 19 including a power transistor 19a and the like are stored. The ground terminal 19b of the power transistor 19a is connected to a connector ground terminal 11'b branched from the ground terminal 11 '.

  The fixing flange 15 is provided with a mounting hole 16 in which, for example, a metal bush 16 'is formed. For example, the fixing flange 15 is fixed to a part of an engine (not shown) with a bolt.

  The iron core 12 in the coil assembly housing portion of the ignition coil for the internal combustion engine is a conductive metal film (not shown) formed on the inner peripheral surface of the insulating case 13 as in the conventional ignition coil for the internal combustion engine. ) And is electrically connected. Also, the coil-side ground terminal 11 ′ in the connector socket 11 on the side opposite to the conductive metal film is in contact with the iron core 12 in the coil assembly housing portion, so that the iron core 12 and the ground terminal 11 ′ are electrically connected. It is connected.

  In the conventional internal combustion engine ignition coil, as shown in FIG. 2, the following steps have been taken in order to electrically connect the ground terminal 21 ′ and the iron core 22. That is, the conductive metal film 24 ′ is bent so as to match the shape of the lower end portion of the iron core 22 to form the fitting portion 24 a, and the iron core 22 is fitted into the fitting portion 24 a, thereby first conducting. The conductive metal film 24 ′ and the iron core 22 are electrically connected. Also, a bent pressure contact portion 21a is provided on one end side of the ground terminal 21 'of the connector socket 21, and the pressure contact portion 21a is pressed into contact with the conductive metal film 24', whereby the ground terminal 21 'and the conductive metal film 24' are provided. And gained continuity. Then, the iron core 22 and the ground terminal 21 'are electrically connected via the conductive metal film 24' that is electrically connected to both the iron core 22 and the ground terminal 21 '.

  Therefore, in the conventional ignition coil for an internal combustion engine, it is very complicated to ground the iron core 22.

  Therefore, in this embodiment, as shown in FIG. 1, the coil-side end portion 11 ′ a of the ground terminal 11 ′ of the connector socket 11 is extended while being bent so as to be close to the bottom portion 12 a of the iron core 12. ing. A stress-reducing conductive rubber 10 is interposed in the gap between the bottom 12a of the iron core 12 and the end 11'a of the ground terminal 11 'of the connector socket 11. The insulating case 13 is filled with a filler 18 to insulate and cover the iron core 12, the coil assembly 12 ', the igniter 19, and the like.

  The conductive rubber 10 is obtained by adding a conductive filler such as carbon black, metal powder, and metal fiber to a rubber material and vulcanizing (crosslinking) the rubber. The conductive rubber 10 has rubber elasticity and conductivity.

  Therefore, when the conductive rubber 10 is interposed between the iron core 12 and the ground terminal 11 ′ of the connector socket 11, the iron core 12 and the ground terminal 11 ′ of the connector socket 11 can be electrically connected. At this time, in order to obtain continuity between the iron core 12 and the ground terminal 11 ′ of the connector socket 11, there is no need for mechanical processing such as welding or caulking both, and electrical connection can be made very easily. .

  Further, since the conductive rubber 10 has an appropriate elasticity as a stress relaxation member, the allowable range is widened when positioning the iron core 12 and the ground terminal 11 ′ of the connector socket 11. Work becomes easy.

  Further, due to the elasticity of the conductive rubber 10, when the iron core 12, the ground terminal 11 'of the connector socket 11 or the filler 18 expands and contracts due to heat, the difference in expansion coefficient of each member can be absorbed. Therefore, it is possible to contribute to prevention of the occurrence of cracks in the filler 18 and, in turn, to improve the quality of the ignition coil.

  In this way, when the iron core 12 and the ground terminal 11 ′ of the connector socket 11 are electrically connected and the iron core 12 is grounded to the engine or the like, the electric charge charged in the iron core 12 can be removed. Therefore, noise can be reduced.

  Moreover, since the iron core 12 can be grounded very easily, it is useful for improving the efficiency of assembly work and reducing costs. That is, since the iron core 12 and the ground terminal 11 'of the connector socket 11 are electrically connected without undergoing a mechanical processing process such as welding or caulking, the work man-hours can be greatly reduced, and it is easy. It is possible to obtain continuity between the two with a simple operation.

  In the above-described embodiment, the iron core 12 and the ground terminal 11 ′ of the connector socket 11 are electrically connected via the conductive rubber 10. Instead of the conductive rubber 10, a conductive adhesive is used. Thus, the iron core 12 and the ground terminal 11 ′ of the connector socket 11 may be electrically connected.

  That is, when a conductive adhesive is applied to the iron core 12 or the ground terminal 11 ′ of the connector socket 11, and then assembled and cured, or conductive adhesion is applied to the gap between the assembled iron core 12 and the ground terminal 11 ′ of the connector socket 11. When the material is injected and cured, the two are electrically connected.

  Also according to this embodiment, the iron core can be easily grounded to the engine or the like, and the electric charge charged to the iron core can be surely removed. Therefore, it is extremely effective for reducing noise.

  Although the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments. The present invention can be modified in various ways without departing from the scope of the claims. For example, the materials of the conductive rubber and the conductive adhesive in the embodiment are not particularly limited as long as they have good conductivity, and known or well-known materials can be adopted.

DESCRIPTION OF SYMBOLS 10 Conductive rubber 11 Connector socket 11 'Ground terminal 11'a End 11'b Connector ground terminal 12 Iron core 12' Coil assembly 12a Bottom 13 Insulating case 15 Fixing flange 16 Mounting hole 16 'Metal bush 18 Filler 19 Igniter 19a power transistor 19b ground terminal 21 connector socket 21a pressure contact portion 21 'ground terminal 22' coil assembly 22 iron core 23 insulating case 24 conductive metal film 24a fitting portion 24 'conductive metal film 25 fixing flange 26 mounting hole 26' Metal bush 28 filler

Claims (2)

Electrically from the primary coil and the secondary coil, the iron core that magnetically couples the primary coil and the secondary coil, the insulating case that houses the coil and the iron core, and the grounding side of the power transistor included in the igniter from the external harness In an ignition coil for an internal combustion engine comprising a ground terminal of a connector socket to be connected,
The ground terminal of the connector socket is disposed close to the iron core so that the ground terminal of the connector socket and the iron core are electrically coupled,
An ignition coil for an internal combustion engine, wherein a conductive rubber for stress relaxation is interposed between a ground terminal of the connector socket and a bottom portion of the iron core to ground the iron core.   The ignition coil for an internal combustion engine according to claim 1, wherein the conductive rubber is a conductive adhesive.

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