JPH066498Y2 - Ignition coil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an ignition coil used in an ignition device for an internal combustion engine.

[Prior Art] An ignition coil used in an ignition device for an internal combustion engine includes an ignition coil main body including a primary coil, a secondary coil, and an insulating sheath that covers these coils, and an iron core insertion hole provided in the ignition coil main body. And an iron core inserted in.

Generally, the primary coil is wound around the outer circumference of the primary bobbin.
The secondary coil is wound around the secondary bobbin fitted around the outer periphery of the secondary coil. The primary bobbin is formed in a tubular shape, and
The inner hole of the next bobbin is the core insertion hole. In many cases, the primary coil and the secondary coil are inserted into an outer case, and a thermosetting insulating resin such as epoxy resin is cast between the case and the primary bobbin to form a primary coil and a secondary coil. Is molded with resin. An insulating outer casing of the ignition coil is formed by the resin molded portion, the outer casing, and the primary bobbin. The iron core is formed in various shapes such as an I-shape, an E-shape, and a U-shape depending on the purpose of use of the ignition coil.

FIG. 3 shows an E-shaped iron core 1 used when the ignition coil is arranged in a three-pole magnet generator. This iron core has three legs 1a, 1b, 1c and these legs. And a yoke portion 1d connecting one end of the portion, and is formed by stacking a large number of steel plates and fastening them by fastening means such as rivets. The iron core 1 has a central leg 1b.
Is inserted into the iron core insertion hole of the ignition coil body 2 and is coupled to the ignition coil body. Magnetic pole faces 1a1 and 1b1 facing the magnetic poles of the rotor of the magnet generator are provided at the tips of the legs 1a to 1c.
And 1c1 are formed.

In the conventional ignition coil, the inner diameter of a part of the iron core insertion hole of the ignition coil body is made smaller than the thickness of the iron core, and the iron core is pressed into the iron core insertion hole of the ignition coil body to fix the iron core to the ignition coil body. ing. Further, the iron core press-fitted into the iron core insertion hole may be further fixed to the ignition coil body with an adhesive.

Further, as shown in FIG. 4, a stopper portion 1e is formed by bending one outer steel plate forming the iron core near the tip of the leg portion 1b of the iron core 1, and the stopper portion 1e is formed.
There is also a device in which the ignition coil body 2 is prevented from coming off.

[Problems to be Solved by the Invention] In the ignition coil as described above, the iron core 1 has a small coefficient of thermal expansion, but the ignition coil body 2, particularly the bobbin and the case, are made of resin, and thus have a large coefficient of thermal expansion. Is very large. Also, the ambient temperature of the ignition coil changes significantly, and it is not uncommon to change from -20 ° C to about 10 ° C. Therefore, even if the iron core is press-fitted into the iron core insertion hole, or the iron core is adhered by an adhesive, However, there is a problem that play is generated between the ignition coil body and the iron core due to a large difference in thermal expansion coefficient between the iron core and the ignition coil body.

If there is looseness between the ignition coil and the iron core, the ignition coil body may drop off from the iron core due to the vibration of the internal combustion engine. Further, if there is a backlash between the ignition coil body and the iron core, the ignition coil body will move due to the vibration of the internal combustion engine, even if the ignition coil body does not fall off. There is a possibility that tension may be applied to the wiring or the like that connects between and the wire, resulting in disconnection.

In addition, as shown in FIG. 4, when the stopper portion 1e is formed by bending one steel plate outside the iron core,
Although it is possible to prevent the ignition coil body from falling off, it is not possible to firmly suppress the ignition coil body by simply bending a part of the steel plate after inserting the iron core into the iron core insertion hole of the ignition coil body. It was not possible to prevent the ignition coil body from moving due to vibration.

Further, since it is necessary to bend the steel plate after inserting the iron core into the iron core insertion hole of the ignition coil, there is a problem that the number of assembling steps of the ignition coil increases and the cost increases.

An object of the present invention is to provide an ignition coil in which the iron core and the ignition coil body are firmly connected to each other to prevent looseness between the iron core and the ignition coil body due to a difference in thermal expansion coefficient between the iron core and the ignition coil body.

[Means for Solving the Problems] The present invention includes an ignition coil body having a primary coil and a secondary coil arranged in an insulating sheath, and a steel plate laminated on the ignition coil body. The present invention relates to an ignition coil having an iron core press-fitted in an iron core insertion hole.

According to the present invention, a saw-toothed projection is provided on the laminated surface of the portion of the iron core that is press-fitted into the iron-core insertion hole, and the saw-toothed projection is configured to bite into the inner surface of the iron-core insertion hole. Has been done.

[Operation] As described above, when a serrated protrusion is provided in a portion of the iron core to be press-fitted into the iron core insertion hole, the serrated protrusion is inserted into the iron core insertion hole when the iron core is press-fitted into the iron core insertion hole. Since the iron core bites into the inner surface of the iron core, the iron core is firmly fixed to the ignition coil body in a state where it cannot be removed from the iron core insertion hole. Therefore, it is possible to prevent looseness between the ignition coil body and the iron core due to the difference in the coefficient of thermal expansion, and it is possible to obtain an ignition coil having high earthquake resistance.

Embodiments Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 and FIG. 2 show an embodiment of the present invention.
FIG. 1 is an exploded perspective view showing the iron core 10 and the ignition coil body 11, and FIG. 2 is a perspective view showing the appearance of the ignition coil of this embodiment.

The iron core 10 includes three leg portions 10a to 10c and a yoke portion 1
It is an E-shaped iron core having 0d and is composed of a laminated body of steel plates. A magnetic pole surface 1 facing the three magnetic poles of the rotor of the magnet generator (not shown) is provided at the tips of the legs 10a to 10c.
0a1, 10b1 and 10c1 are formed.

The ignition coil body 11 includes a primary coil (not shown) wound around the outer circumference of the primary bobbin 12, and a secondary coil wound around the outer circumference of the primary coil via a secondary bobbin (see FIG. (Not shown) is inserted into a cup-shaped case 13, and a thermosetting resin 14 is cast into the case 13 to have a known structure. The inner hole of the primary bobbin 12 is an iron core insertion hole. It is 15.

The ignition coil body has a high-voltage cord holder 18 to which the primary terminal fitting 16 and the high-voltage cord 17 are inserted and connected. The primary terminal fitting 16 and the high-voltage cord holder 1
8 are fixed in a state in which a part of each is embedded in the resin 14. The primary terminal 16 is connected to the non-grounded end of the primary coil, and the grounded end of the primary coil is
It is connected to the ground terminal together with the ground-side end of the next coil. The ground terminal is connected to the iron core after the iron core is attached to the ignition coil body.

Inside the high voltage cord holder 18, a high voltage terminal electrically connected to the non-grounded end of the secondary coil is provided.
The core wire of the high voltage cord 17 is connected to the high voltage terminal.

A pair of protruding portions 19a, 19b and 20a, 20b protruding in opposite directions are provided on the side surface of the case 13 on the side of the open end.
Are provided between the protrusions 19a and 19b and between the protrusions 20.
legs 10a and 10c of the iron core 10 between a and 20b, respectively.
Grooves 21 and 22 for fitting and positioning are formed.

In the ignition coil body described above, the primary bobbin 12 and the case 13 are made of thermoplastic resin molded products.

In this embodiment, the central leg portion 10b of the iron core 10 is press-fitted into the iron core insertion hole 15. The laminated surface formed on both sides of the leg portion 10b in the width direction has a large number of inclined surfaces 10e1 which are inclined so as to approach the central axis of the leg portion 10b toward the tip end side of the leg portion 10b. Serrated projections 10e of
10e, ... Are provided. The width dimension of the leg portion 10b measured between the tip portions of the protrusions 10e is set larger than the width dimension of the iron core insertion hole 15.

The leg portions 10a and 10c of the iron core 10 configured as described above are fitted into the groove portions 21 and 22, and the leg portion 10b is press-fitted into the iron core insertion hole 15 of the ignition coil body 11 as shown in FIG. Attach the iron core 10 to the ignition coil body 11. Then, an adhesive is injected into the gap between the leg portion 10b and the primary bobbin 12 to reinforce it to complete the ignition coil.

Sawtooth-shaped projections 10e, 1 provided on the leg portion 10b of the iron core
0e, ... have an inclined surface inclined so as to approach the central axis side of the leg portion 10b as it goes toward the tip end side of the leg portion 10b, so that the leg portion 10b is press-fitted into the iron core insertion hole. It can be inserted relatively easily. Once the leg portion 10b is inserted into the iron core insertion hole, the projections 10e, 10e, ... Enter into the inner surface of the iron core insertion hole 15 (generally made of a thermoplastic resin), so that the iron core insertion hole 1 is expanded by thermal expansion.
Even if the inner diameter of 5 is enlarged, the leg portion 10b is held firmly fixed in the core insertion hole. Therefore, it is possible to prevent the ignition coil body from moving or falling off due to the vibration of the internal combustion engine, and it is possible to improve the earthquake resistance.

In the above embodiment, the E-shaped iron core is used,
Of course, the present invention can be applied to the case where an iron core having another shape such as an I shape is used.

Further, the structure for drawing out the terminals from the ignition coil body is not limited to the above example. For example, in the above example, a part of the high-voltage cord holder is embedded and fixed in the resin 14, but the high-voltage cord holder may be formed integrally with the case 13.

[Effects of the Invention] As described above, according to the present invention, a saw-toothed projection is provided on the iron core, and when the iron core is press-fitted into the iron-core insertion hole, the saw-toothed projection bites into the inner surface of the iron-core insertion hole. As a result, the iron core can be firmly fixed to the ignition coil body. Therefore, it is possible to prevent looseness between the ignition coil body and the iron core due to the difference in the coefficient of thermal expansion, and it is possible to obtain an ignition coil having high earthquake resistance.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention. FIG. 1 is an exploded perspective view, FIG. 2 is a perspective view of a completed state, and FIGS. 3 and 4 are conventional ignition coils. It is the perspective view which showed the iron core used. 10 ... Iron core, 10a to 10c ... Leg portion, 10e ... Serrated protrusion, 10e1 ... Sloping surface, 11 ... Ignition coil body, 15 ... Iron core insertion hole.

Claims (1)

[Scope of utility model registration request] 1. An ignition coil body having a primary coil and a secondary coil arranged in an insulating sheath, and a stack of steel plates, which are press-fitted into an iron core insertion hole provided in the ignition coil body. In an ignition coil provided with an iron core, a sawtooth-shaped projection is provided on a laminated surface of a portion of the iron core that is press-fitted into the iron-core insertion hole, and the sawtooth-shaped projection bites into the inner surface of the iron-core insertion hole. Ignition coil characterized in that.