JPH10223464A - Ignition coil device for internal-combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the diameter of a primary coil without a bobbin by a method wherein an insulating film is wound on a core which is arranged in the center and an insulating covered wire is wound on it so as to form the primary coil. SOLUTION: First, an insulating film 9 is wound on a core 7, and an insulating covered copper wire is wound on it so as to assemble a primary coil 10. The primary coil 10 is inserted into bobbin 11 on which a secondary coil 12 is wound, and the bobbin 11 is bused in an outside case 14 in which a shielding plate 13 is housed in advance. Then, a spring 17 is attached by a screw 18, and high-voltage terminals 15, 16 are connected. In addition, the end part of the primary coil 10, the secondary coil 12 and an ignitor part 2 are connected, an epoxy resin 20 and a silicone casting agent 21 are injected so as to be thermally hardened, and respective components which are housed inside the outside case 14 are insulated and fixed. When the core 7 is used also as a bobbin for the primary coil 10, an ignition coil device can be miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ignition coil device for an internal combustion engine, and more particularly to an ignition coil device for an internal combustion engine which is mounted in a plug hole of an engine body and directly applies a high voltage to a spark plug.

[0002]

2. Description of the Related Art Conventionally, there has been proposed an ignition coil device for an internal combustion engine which is mounted in a plug hole of an engine body and directly applies a high voltage to a spark plug. This conventional ignition coil device includes an iron core, a primary coil formed by winding an insulated wire around a small-diameter bobbin, and a secondary coil formed by winding an insulated wire around a large-diameter bobbin. The configuration was such that it was arranged coaxially in the case, and then the insulating resin was vacuum-poured into the outer case and thermosetted.

[0003]

However, in the above-mentioned conventional ignition coil device, the primary coil and the secondary coil each have a configuration in which a bobbin is wound with an insulated wire.
The diameters of the primary coil and the secondary coil become large, and furthermore, in order to prevent dielectric breakdown between the primary coil and the secondary coil, the distance between the primary coil and the secondary coil must be made larger than a predetermined value. Therefore, it was difficult to reduce the size of the ignition coil device.

An object of the present invention is to solve the above-mentioned conventional problems, and in particular, to provide an ignition coil device for an internal combustion engine that can reduce the diameter of a primary coil.

[0005]

In order to achieve the above object, the present invention does not use a bobbin for a primary coil, but wraps an insulating film around an iron core disposed at the center, and places an insulating film on the insulating film. A primary coil is formed by winding a covered wire. Accordingly, since the bobbin is not used, the iron core wound with the insulating film can also be used as the bobbin of the primary coil, the diameter of the primary coil can be reduced, and the ignition coil device can be downsized. Can be. In addition, since the diameter of the primary coil can be reduced, the distance between the primary coil and the secondary coil can be increased, and dielectric breakdown between the primary coil and the secondary coil can be prevented. Has advantages.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is to provide insulation between an outer peripheral surface of a bobbin and an inner peripheral surface of an iron core via an insulating film. A primary coil formed by winding a covered wire is disposed, the primary coil and the secondary coil are housed in a cylindrical outer case, and an insulating resin is poured into the outer case.
The diameter of the secondary coil can be reduced, and the size of the ignition coil device can be reduced, and dielectric breakdown between the primary coil and the secondary coil can be prevented.

According to a second aspect of the present invention, there is provided an internal combustion engine according to the first aspect, wherein a plurality of magnetic plates having different widths are laminated to form a substantially cylindrical iron core. This is an ignition coil device for an engine, and an iron core can be easily manufactured.

According to a third aspect of the present invention, a polygonal iron core is formed by laminating a plurality of magnetic plates having the same width and combining a plurality of substantially parallelogram blocks.
An ignition coil device for an internal combustion engine as described above, wherein an iron core can be easily manufactured.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 shows an outer shape of an ignition coil device according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a cylindrical ignition coil main body, in which a primary coil, a secondary coil, an iron core, and the like are housed. Reference numeral 2 denotes an igniter section mounted on the upper portion of the ignition coil main body 1. The igniter section 2 has an igniter main body 2A in which a power transistor, a switching transistor, and the like are housed, a connector section 2B, and mounting screws. It is composed of a mounting portion 2D in which a mounting hole 2C is formed. Reference numeral 3 denotes a spark plug connection portion which is a rubber cylindrical body fitted to the lower end of the ignition coil body 1.

FIG. 2 shows a state in which the ignition coil device shown in FIG. 1 is mounted on an engine. In FIG. 2, reference numeral 4 denotes an engine main body, and a plug hole 4A is formed in the engine main body 4, and a spark plug 5 is attached to the bottom of the plug hole 4A. Reference numeral 6 denotes a cylinder head.
A hole 6A communicating with A is formed, and a protrusion 6C having a screw hole 6B into which the ignition coil device is screwed is formed. As shown in FIG. 2, when the ignition coil main body 1 of the ignition coil device is inserted into the plug hole 4A through the hole 6A of the cylinder head 6, the high-voltage terminal at the lower end of the ignition coil main body 1 is connected to the connection portion of the ignition plug 5. . The ignition coil device is fixed by inserting the mounting screw S into the hole 2C of the mounting portion 2D of the igniter unit 2 and screwing the screw 8 into the screw hole 6B of the projection 6C of the cylinder head 6. When a current is supplied through the connector 2B, it is turned on and off by the switching transistor of the igniter 2 and is supplied to the primary coil in the ignition coil body 1, thereby generating a high voltage in the secondary coil. A voltage is applied to the spark plug 5 to generate a spark.

FIG. 3 shows a cross section of the ignition coil device.
FIG. 4 is an enlarged view of a portion P in FIG. In FIG. 3, reference numeral 7 denotes a substantially cylindrical iron core. The iron core 7 is formed by laminating magnetic plates having different widths as shown in FIG. Reference numerals 8A and 8B denote magnets disposed at the upper and lower ends of the iron core 7, and these magnets 8A and 8B are used to generate a bias magnetic field. Reference numeral 9 denotes an insulating film wound around the outer periphery of the iron core 7 and the magnets 8A and 8B, and a polyimide film or the like is used as the insulating film 9. Reference numeral 10 denotes a primary coil wound around the outer periphery of the insulating film 9, and the primary coil 10 is made of an insulated copper wire. Reference numeral 11 denotes a cylindrical bobbin, and a secondary coil 12 is formed by winding an insulated copper wire around the outer periphery of the bobbin 11. Reference numeral 13 denotes a cylindrical shield plate, and a cutout (not shown) is formed in the shield plate 13 along an axis. Reference numeral 14 denotes a cylindrical outer case made of an insulating resin (for example, polyphenylene sulphite), and a case constituting the igniter unit 2 is integrally formed on the upper part of the outer case 14. Reference numeral 15 denotes a first high-voltage terminal attached to the bottom surface of the bobbin 11, to which one end of the secondary coil 12 is connected. Reference numeral 16 denotes a second high-voltage terminal previously mounted inside the outer case 14. Reference numeral 17 denotes a spring. The upper end of the spring 17 is fixed to the bottom surface of the bobbin 11 by a screw 18. Further, the second high voltage terminal 16 is pressed against the first high voltage terminal 15 by the screw 18. For this reason, one end of the secondary coil 12 and the spring 17
First high-voltage terminal 15 and second high-voltage terminal 16 and screw 1
Electrical continuity is attained through 8. Further, by fitting the ring-shaped groove 3A formed on the inner peripheral surface of the spark plug connection portion 3 into the ring-shaped protrusion 14A formed at the lower portion of the outer case 14, the ignition plug connection portion 3 is moved outward. It is held at the lower part of case 14. Reference numeral 19 denotes an annular shield cover. The shield cover 19 is mainly used for waterproofing when the ignition coil device is attached to the engine body.

When assembling the ignition coil device according to the present embodiment, first, an insulating film 9 is wound around an iron core 7 and an insulating-coated copper wire is wound around the iron core 7 to assemble a primary coil 10. The primary coil 10 is inserted into a bobbin 11 around which a secondary coil 12 is wound, and the bobbin 11 is further housed in an outer case 14 in which a shield plate 13 is housed in advance.
Next, mounting of the spring 17 and connection of the high voltage terminals 15 and 16 are performed with the screws 18. Further, the end of the primary coil 10, the secondary coil 12, and the igniter unit 2 are connected, and thereafter, an epoxy resin 20 and a silicone casting agent 21 (see FIG. 4) are injected by vacuum casting, and thermally cured. Then, the components housed in the outer case 14 are insulated and mechanically fixed to complete.

Then, when the ignition coil device shown in FIG. 3 is inserted into the plug hole 4A of the engine body 4 as shown in FIG.
A high voltage generated in the secondary coil 12 in contact with the connection portion of the ignition plug 5 is applied to the ignition plug 5.

As described above, in the prior art, an insulating-coated copper wire is wound around a bobbin to form a primary coil. In contrast, in the present embodiment, an insulating film 9 is wound around the outer peripheral surface of an iron core 7.
Since the primary coil 10 is formed by winding an insulation-coated copper wire on the insulating film 9, the diameter of the primary coil 10 can be reduced because the bobbin is not used, and the outer diameter of the ignition coil device is reduced. And the size of the ignition coil can be reduced. In addition, since the distance between the secondary coil 12 and the primary coil 10 can be increased, the insulation between the primary coil 10 and the secondary coil 12 can be increased. Therefore, the output voltage generated by the secondary coil 12 can be increased.

(Embodiment 2) FIG. 6 shows an iron core according to a second embodiment of the present invention. In the second embodiment, three magnetic parallel plate blocks 20 each having a substantially parallelogram are formed by slightly shifting magnetic plates having the same width, and these three blocks 20 are combined as shown in FIG. 21, an insulating film 22 is wound on the outer peripheral surface of the iron core 21, and an insulating coated copper wire is wound on the insulating film 22 to form a primary coil 23. Also, the same effect as in the first embodiment can be obtained.

[0016]

According to the present invention, as apparent from the above embodiment, the iron core wound with the insulating film can be used also as the bobbin of the primary coil, so that the diameter of the primary coil can be reduced, and This has the effect of reducing the size of the coil device and easily preventing dielectric breakdown between the primary coil and the secondary coil.

[Brief description of the drawings]

FIG. 1 is a front view of an ignition coil device according to Embodiment 1 of the present invention.

FIG. 2 is a sectional view showing a state in which the ignition coil device according to Embodiment 1 of the present invention is mounted on an engine body.

FIG. 3 is a cross-sectional view of the ignition coil device according to Embodiment 1 of the present invention.

FIG. 4 is an enlarged sectional view of a part P in FIG. 3;

FIG. 5 is a plan view of an iron core of the ignition coil device according to Embodiment 1 of the present invention.

FIG. 6 is a plan view of an iron core of the ignition coil device according to Embodiment 2 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ignition coil main body 2 Igniter part 3 Ignition plug connection part 4 Engine main body 5 Ignition plug 6 Cylinder head 7 Iron core 8A, 8B Magnet 9 Insulation film 10 Primary coil 11 Bobbin 12 Secondary coil 13 Shield plate 14 Outer case 15 First High voltage terminal 16 second high voltage terminal 17 spring 18 screw 19 shield cover 20 epoxy resin 21 silicone casting agent S mounting screw

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Akira Kanazawa Inventor 4-3-1 Tsunashima Higashi, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture Inside Matsushita Communication Industrial Co., Ltd. (72) Akira Nakatsuka Tsunashima, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture Matsushita Communication Industrial Co., Ltd.

Claims (3)

[Claims] A primary coil formed by winding an insulation-coated wire on an outer peripheral surface of an iron core via an insulating film, inside a secondary coil formed by winding an insulation-coated wire on an outer peripheral surface of a bobbin; An ignition coil device for an internal combustion engine in which a primary coil and a secondary coil are housed in a cylindrical outer case, and an insulating resin is poured into the outer case. 2. The ignition coil device for an internal combustion engine according to claim 1, wherein an iron core formed by laminating a plurality of magnetic plates having different widths into a substantially cylindrical shape is used. 3. The ignition coil device for an internal combustion engine according to claim 1, wherein a plurality of magnetic plates having the same width are laminated and a plurality of substantially parallelogram blocks are combined to form a polygonal iron core.