JP2006291760A - Ignition coil for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition coil for an internal combustion engine capable of preventing liquid such as water from staying at a connection part of a boot part and an insulating pipe part and a boot part from coming off. <P>SOLUTION: This ignition coil consists of a rubber part 32 made of an elastic body for insulating and sealing high voltage supplied from an ignition coil main body 2 and preventing water from intruding in a plug hole, a boot part 34 made of an elastic body attached to a insulator part of a spark plug for sealing and insulating, and an insulating pipe part 33 provided with a conductive body 31 supplying high voltage supplied from an ignition coil main body 2 to a spark plug. An umbrella shape projection part 36 including an inclined surface 36a expanded toward an end to expand diameter of an insulating pipe part 33 is provided on a connection part of the insulating pipe part 33 and the boot part 34. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ignition coil for an internal combustion engine that generates a high voltage, for example, in order to cause spark discharge in an ignition plug of an automobile engine, and in particular, an ignition coil body is installed above the plug hole of the engine, and the ignition plug and ignition The present invention relates to an ignition coil for an internal combustion engine in which a coil is connected by a cylindrical protector part containing a conductor.

The outline of the ignition coil is, for example, as shown in FIG.
That is, the ignition coil 1 includes an ignition coil main body 2 and a protector portion 3 that connects the ignition coil main body 2 and an engine-side ignition plug (not shown). The ignition coil body 2 includes at least a primary coil 21 and a secondary coil 22, an iron core 23 (a center iron core 23a and a side iron core 23b) that magnetically couples both the coils 21 and 22, and a case 24 for housing these. The case 24 is filled with resin and is called a mold-type ignition coil.

  The ignition coil body 2 is installed above the plug hole of the engine head, and the ignition coil body 2 and the ignition plug on the engine side are electrically connected. Although it depends on the shape of the plug hole on the engine side from the engine side to the spark plug on the engine side, it usually has some distance and cannot be directly connected. Therefore, the protector unit 3 with the conductor 31 is provided. Connected using.

  The protector section 3 is usually composed of a rubber rubber section 32 that houses the high-voltage terminal 25, a resin-made insulating pipe section 33 that encloses a conductor 31 such as a coil spring, and the insulating pipe section. And a rubber boot portion 34 that accommodates the plug end of 33 (see, for example, Patent Document 1).

JP-A-8-144917

  For example, as shown in FIG. 2, the conventional protector portion 3 has a flat upper end surface 35 of the boot portion 34. For this reason, when water enters the plug hole fitted with the spark plug, the intruded water may flow down the outer peripheral surface of the insulating pipe portion 33 and accumulate on the upper end surface 35 of the boot portion 34. . If water accumulates, there is a possibility that the boot part 34 and the insulating pipe part 33 may deteriorate due to this water. And if the boot part 34 and the insulation pipe part 33 deteriorate, insulation performance will fall and there exists a possibility that it may stop igniting worst.

  Further, when the ignition coil 1 is removed from the plug hole on the engine side, in the conventional ignition coil 1, the corner of the boot portion 34 may interfere with the inner wall of the plug hole, and the boot portion 34 may fall off the insulating pipe portion 33. There was this.

  The problem to be solved by the present invention is to prevent the retention of a liquid such as water at the connecting portion between the boot portion and the insulating pipe portion and to prevent the boot portion from falling off.

  In the ignition coil for an internal combustion engine, the protector part is a rubber part made of an elastic body for insulatingly sealing high voltage supplied from the ignition coil body and preventing liquid from entering the plug hole of the engine head, A boot part, which is attached to an insulator part of the spark plug, is made of an elastic body for insulating sealing, and the rubber part and the boot part are connected to each other, and a high voltage supplied from the ignition coil body is supplied to the engine head. An insulating pipe portion having a conductor to be supplied to the attached spark plug, and a connecting portion between the insulating pipe portion and the boot portion is provided with a protrusion for expanding the diameter of the insulating pipe portion. It is characterized by that.

  The liquid that has entered the plug hole of the engine, such as water, does not collect on the upper end surface of the boot portion. Further, when the ignition coil is removed from the plug hole of the engine, the corner of the boot portion does not interfere with the inner wall of the plug hole, and the boot portion does not fall off from the insulating pipe portion.

  For internal combustion engines where a projection formed in the shape of an umbrella having an inclined surface that widens at the end is provided at the connection between the insulation pipe and the boot, so that water and other liquids do not accumulate at the connection between the boot and the insulation pipe I realized an ignition coil.

  FIG. 1 is a cross-sectional view of an ignition coil 1 according to the present invention. That is, the ignition coil 1 includes an ignition coil main body 2 and a protector portion 3 that connects the ignition coil main body 2 and an engine-side ignition plug (not shown). The ignition coil body 2 includes a primary coil 21 and a secondary coil 22, an iron core 23 (a center iron core 23a and a side iron core 23b) that magnetically couples both the coils 21 and 22, and a case 24 that houses them. The case 24 is filled with resin.

  On the other hand, the protector 3 includes an insulating pipe 33 having a conductor 31 for supplying a high voltage supplied from the ignition coil body 2 to an ignition plug attached to the engine head, and a rubber part 32 and a boot part to be described later. 34.

  That is, at the upper end of the insulating pipe part 33 constituting the protector part 3, the high voltage supplied from the ignition coil main body 2 is insulated and sealed, and a liquid such as water enters the plug hole of the engine head. In order to prevent this, for example, a rubber part 32 made of an elastic material such as rubber is joined.

  In addition, a boot portion 34 made of an elastic material such as rubber is attached to the lower end of the insulating pipe portion 33 to be attached to an insulator portion (not shown) of the spark plug for insulation sealing.

  A projecting portion 36 is provided at a connection portion between the insulating pipe portion 33 and the boot portion 34 so that liquid such as water does not collect on the upper end surface 35 of the boot portion 34. For example, the protrusion 36 may be formed in an umbrella shape having an inclined surface 36a that widens toward the end.

  According to this embodiment, even if water enters the plug hole and flows down along the outer peripheral surface of the insulating pipe portion 33, the water is guided to the outer surface side of the boot portion 34 by the inclined surface 36 a of the projection portion 36. be able to. For this reason, even if the upper end surface 35 of the boot part 34 is flat, water does not collect in the connection part of the boot part 34 and the insulation pipe part 33. FIG.

  In addition, when the spark plug is pulled out from the plug hole, the inclined surface 36a of the projection 36 serves as a guide, so that the inner wall of the plug hole and the boot portion 34 do not interfere with each other, and the boot portion 34 is separated from the insulating pipe portion 33. There is no fear of falling off.

It is a schematic longitudinal cross-sectional view of the ignition coil for internal combustion engines which concerns on this invention. It is a front view which shows the outline of the conventional ignition coil.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ignition coil 2 Ignition coil main body 3 Protector part 21 Primary coil 22 Secondary coil 23 Iron core 24 Case 25 High voltage terminal 31 Conductor 32 Rubber part 33 Insulation pipe part 34 Boot part 35 Upper end surface 36 Projection part 36a Inclined surface

Claims (2)

At least an ignition coil main body that generates a high voltage including an iron core that magnetically couples both the primary coil and the secondary coil, and a case that houses these coils, and a high voltage that is attached to and supplied to the ignition coil main body In the ignition coil for an internal combustion engine configured with a protector section that supplies the spark plug to the spark plug,
The protector part is
A rubber portion made of an elastic material for insulatingly sealing a high voltage supplied from the ignition coil body and preventing liquid from entering the plug hole of the engine head;
A boot part attached to the insulator part of the spark plug and made of an elastic body for insulation sealing;
The rubber part and the boot part are connected, and an insulating pipe part having a conductor for supplying a high voltage supplied from the ignition coil body to an ignition plug attached to the engine head, and
An ignition coil for an internal combustion engine, wherein a projecting portion for expanding the diameter of the insulating pipe portion is provided at a connection portion between the insulating pipe portion and the boot portion.   The ignition coil for an internal combustion engine according to claim 1, wherein the protruding portion is formed in an umbrella shape having a divergent inclined surface.

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