JP2007227411A - Ignition coil device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small ignition coil device for internal combustion engine excellent in waterproofness. <P>SOLUTION: An intake air structure excellent in waterproofness can be obtained by simplifying the intake air passage, and installing a thin film resin member of porous structure passing only air at a part of the passage. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ignition coil device for an internal combustion engine that is mounted for each ignition plug of the internal combustion engine.

  An internal combustion engine ignition coil device is inserted into a plug hole formed in a cylinder head and connected to an ignition plug. When the ignition coil device is inserted into the plug hole or when the air in the plug hole is thermally expanded due to the operation of the internal combustion engine, the air needs to be discharged from the plug hole to the outside.

  Therefore, an air vent hole (groove) that communicates the inside and outside of the plug hole is formed in the ignition coil device. It is necessary to prevent water from entering the plug hole from the outside through the air vent hole. There is.

  Therefore, in the technique described in Patent Document 1, in order to prevent water from entering the plug hole through the vent hole (air vent hole), a portion where a seal rubber for closing the opening of the plug hole is attached. A first groove connected to the outside is formed on the low-voltage terminal socket side of the first, a second groove connected to the mounting portion and a third groove connected to the second groove on the low-voltage socket side are formed, and the closed space portion The first groove and the third groove are configured to communicate with each other.

  When water is about to enter from the outside, the water is stored in the space portion, and intrusion into the plug hole is prevented. And the water stored in the space part at the time of exhausting from the inside of a plug hole to the exterior is discharged | emitted outside.

JP 2000-291523 A

  However, in the ignition coil device for an internal combustion engine in the above-described prior art, as described above, the ventilation hole (intake passage) is formed in the first to third grooves and the space portion in order to ensure waterproofness. However, a complicated labyrinth structure must be adopted, and the structure of the seal rubber and coil case having a waterproof function between the ignition coil and the plug hole becomes complicated and the size of the coil is increased, which is an obstacle to downsizing the ignition coil device for an internal combustion engine. It was.

  An object of the present invention is to realize an ignition coil device for an internal combustion engine that is excellent in waterproofness, can be miniaturized, and is easy to manufacture.

  In order to achieve the above object, the present invention is configured as follows.

  It has a cylindrical ignition coil part inserted into the plug hole and a resin-made ignition circuit storage case part provided at the head, and one end of the resin part of the ignition circuit storage part opens into the plug hole. A cover having an air passage that opens to the outside at the other end and that covers the opening on the other end of the air passage was attached to the ignition circuit housing case.

  Thereby, in this invention, a ventilation path becomes a simple shape, size reduction is possible, and manufacture becomes easy. Further, by covering the opening of the air passage with the cover, it is possible to obtain an air intake structure with excellent waterproofness.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIG.

  A primary coil 11 is wound around a primary bobbin 10 formed of a thermoplastic synthetic resin.

  A secondary coil 9 is wound around a secondary bobbin 8 formed of a thermoplastic synthetic resin.

The primary coil 11 is formed by laminating an enameled wire having a wire diameter of about 0.5 to 0.7 mm several tens of times per layer, about 150 to 250 times in total over several layers. The secondary coil 9 has a wire diameter of 0.03 to
An enameled wire of about 0.05 mm is divided and wound about 15,000 to 25,000 times. The coil case 1 c is formed of a thermoplastic synthetic resin similar to the primary bobbin 10. The center core 7 is disposed inside the secondary bobbin 8 by press laminating silicon steel plates. A magnet 6 is disposed on the end surface of the center core 7. The side core 12 is disposed outside the coil case 1c, and a silicon steel plate is rounded into a tubular shape. However, in order to prevent a short turn of the magnetic flux, at least one place on the circumference of the side core 12 is provided with a cut. An igniter case 1a with a connector at the upper part of the coil is provided with an igniter 13 that cuts off the current to the primary coil 11. The coil case 1c and the igniter case 1a with a connector are made of insulating thermosetting synthetic resin. An epoxy resin 14 is poured and cured by heating, and then a decorative cover 5 made of thermoplastic synthetic resin is placed on the upper surface of the igniter case 1a with connector to form the ignition coil device 1.

  An annular seal rubber 2 is attached below the igniter case 1a with a connector above the coil case 1c inserted into an insertion portion of a plug hole (not shown) formed in the cylinder head. A part of the seal rubber 2 is provided with an annular plug hole side convex part 2a and a igniter case 1a side convex part 2b with a connector, and the plug hole side convex part 2a is in pressure contact with the inner surface of the plug hole. The igniter case with connector 1a side convex portion 2b is pressed against the inner surface of the igniter case with connector 1a to ensure waterproofness.

  A groove for forming the coil case side intake passage 4b is formed in a part of the coil case 1c and the seal rubber 2, and the igniter case 1a with connector for forming the igniter case side intake passage 4a with connector is formed. A hole is formed. And by providing the recessed part 1b in a part of igniter case 1a with a connector and arrange | positioning the porous member 3, the inside and outside of a plug hole can be ventilated. The cover 5 that covers the ignition coil head so as to cover the porous member 3 also serves to prevent water from splashing directly on the porous member 3 unexpectedly for cosmetic purposes.

  Since the porous member 3 has micropores, the porous member 3 has a characteristic that gas passes but liquid does not pass. This prevents water from entering the plug hole. The porous member 3 is typically a tetrafluoroethylene resin porous membrane.

  The porous member 3 can be fixed by adhesive fixing by double-sided tape or caulking, and welding fixing that is possible when the other side is a resin. In severe cases such as an ignition coil for an internal combustion engine used in a temperature range of −40 ° C. to 150 ° C., caulking fixing or welding fixing is suitable, but in the case of an ignition coil that requires downsizing, a space is required. The minimum welding fixation is considered optimal.

  Since the igniter case 1a with a connector is formed of a resin such as polybutylene terephthalate (PBT) or polyphenylene sulfide (PPS), it can be welded at a temperature lower than the heat resistance temperature of the tetrafluoroethylene resin that is the porous member 3. it can. Therefore, strong fixing strength can be obtained without damaging the porous member 3.

  When welding to the igniter case 1a with a connector, the diameter of the through hole for the intake passage 4a of the igniter case 1a with a connector can only be about φ0.5 to φ2 due to space. The resin on the case 1a side melts and deforms in a direction to close the hole. In order to prevent this, it is necessary to enlarge a part of the through hole for the intake passage 4a on the side where the porous member 3 is attached.

  As described above, according to the first embodiment of the present invention, a part of the through hole for the intake passage 4a on the side of the igniter case with connector 1a to which the porous member 3 is attached is enlarged in a tapered shape or the like. In addition, it is possible to prevent the through hole portion for the intake passage 4a from being blocked when the porous member 3 is fixed, and it is possible to ensure the intake performance and the waterproofness.

  FIG. 2 shows a second embodiment in which the porous member 3 is installed on the side surface side different from the casting surface side of the coil portion insulating epoxy resin 14 with respect to FIG. The reason for installing the porous member 3 on the side surface different from the casting surface side of the epoxy resin 14 for coil part insulation is that the epoxy resin 14 adheres to the surface of the porous member 3 when the epoxy resin 14 is injected and cured. This is to prevent the vent hole from being blocked.

  As described above, with the above-described structure, it is possible to provide a small-sized internal combustion engine ignition coil with high waterproof reliability.

  The aspect of this example and its effects are as follows.

  (1) In an ignition coil device for an internal combustion engine having an elastic body that is inserted into a plug hole formed in a cylinder of the internal combustion engine and connected to the spark plug and waterproofly seals the plug hole opening, the inside and outside of the plug hole The porous structure member which gas passes and blocks | interrupts the liquid is arrange | positioned in this ventilation path.

  (2) Preferably, in the above (1), a part of the air passage is formed as a through passage that penetrates the case, and the porous structure member is an inlet or an outlet of the through passage provided in the case. Provided in the department.

  By providing a porous structural member that simplifies the air passage, allows gas to pass through a part of the air passage, and blocks the liquid, it is possible to provide an air intake structure with excellent waterproofness.

  Further, since the seal rubber does not require a labyrinth structure, the seal rubber has a simple structure and can be a small and inexpensive waterproof structure.

  INDUSTRIAL APPLICABILITY The present invention can be used for a cylindrical ignition coil that is inserted into a plug hole and that has an igniter case on the top, and a so-called plug top type ignition coil.

The principal part fracture | rupture block diagram of the ignition coil for internal combustion engines which is the 1st Embodiment of this invention. The principal part fracture | rupture block diagram of the ignition coil for internal combustion engines which is the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ignition coil apparatus, 1a ... Igniter case with connector, 1b ... Porous structure member attachment dent, 1c ... Coil case, 2 ... Seal rubber, 2a ... Plug hole side convex part, 2b ... Igniter case side convex part with connector, DESCRIPTION OF SYMBOLS 3 ... Porous member, 4a ... Igniter case side intake passage with connector, 4b ... Coil case side intake passage, 5 ... Cover, 6 ... Magnet, 7 ... Center core, 8 ... Secondary bobbin, 9 ... Secondary coil, 10 ... Primary bobbin, 11 ... primary coil, 12 ... side core, 13 ... igniter, 14 ... epoxy resin.

Claims (8)

  A cylindrical ignition coil portion inserted into a plug hole of each cylinder of the internal combustion engine, and an ignition circuit storage case portion made of a resin material provided at the head thereof, the resin portion of the ignition circuit storage portion, An internal combustion engine ignition coil comprising an air passage having one end opened to a plug hole and the other end opened to outside air, and a cover that covers the opening on the other end side of the air passage attached to the ignition circuit housing case.   The ignition coil for an internal combustion engine according to claim 1, wherein a moisture absorbing member that captures moisture through air is provided in a part of the air passage.   The ignition coil for an internal combustion engine according to claim 2, wherein the moisture absorbing member is attached to an opening on the other end side of the air passage.   2. An ignition coil for an internal combustion engine according to claim 1, comprising a waterproof member made of an elastic material that seals between a plug hole opening and an outer periphery of the ignition coil portion.   4. The ignition coil for an internal combustion engine according to claim 3, wherein the cover covers a head of the ignition circuit housing case.   6. The ignition coil device for an internal combustion engine according to claim 2, wherein the hygroscopic member is formed of a thin film resin material having a porous structure.   7. The ignition coil device for an internal combustion engine according to claim 6, wherein the moisture absorbing member is installed on a casting surface side of an insulating thermosetting resin injected into the ignition coil portion. 2. The ignition coil device for an internal combustion engine according to claim 1, wherein the other end opening of the intake passage opens to a side surface portion of the ignition coil storage case.

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