JP5847112B2 - Ignition coil for internal combustion engine - Google Patents

Description

The present invention relates to an ignition coil for supplying a high voltage to an ignition plug provided in an internal combustion engine, and more particularly to an ignition coil for an internal combustion engine in which a coil portion is disposed outside a plug hole.

2. Description of the Related Art Conventionally, an ignition coil for an internal combustion engine has been required to reduce the size and weight of components disposed in the engine room in recent years in order to narrow the engine room and widen the vehicle interior space. In addition, there is an urgent need to improve fuel efficiency due to the rising oil prices and the depletion of fossil fuels.In order to ensure ignition even in lean combustion with reduced fuel injection volume, the number of windings and the core There is also a demand for higher output by increasing the size. Further, when the engine room is narrowed, various on-vehicle control parts constituting the automobile are densely packed, and the parts are easily affected by noise.

As such an ignition coil, for example, a structure as disclosed in JP 2007-214198 A (hereinafter “Patent Document 1”) is known. A cross-sectional view of the internal combustion engine ignition device of Patent Document 1 is shown in FIG. The ignition device for an internal combustion engine of Patent Document 1 is housed in a case 40 in which a transformer in which a primary coil 10 and a secondary coil 20 are wound around an iron core 30 in which thin steel plates are laminated is made of conductive plastic. Insulating resin 80 is filled to insulate and fix the transformer. The conductive plastic constituting the case 40 is kneaded with metal fibers, and a high-pressure tower 42 having an insertion hole is fitted into the bottom surface of the case 40. Further, on one side surface of the case 40, a low voltage connector 60 having an input terminal connected to the primary coil 10 and supplying an exciting current to the primary coil 10 is provided. A high voltage output terminal connected to the coil 20 is inserted.

The internal combustion engine ignition device having the above-described configuration is manufactured according to an assembly procedure described below. First, the high voltage tower 42 with the high voltage output terminal inserted is press-fitted into the case 40. Next, a transformer that is electrically connected to the input terminal of the low-voltage connector 60 is connected to the high-voltage output terminal in the case 40. Thereafter, a configuration has been proposed in which the insulating resin 80 is injected and cured into the case 40 from the low voltage connector 60 side to insulate and fix the low voltage connector 60, the high voltage output terminal, and the transformer.

JP 2007-214198 A

However, the conventional ignition coil for internal combustion engine has the following problems. That is, in Patent Document 1, even if the case has a complicated shape, noise can be prevented from being radiated to the outside from the transformer without requiring a special man-hour, but it is required for the ignition coil. Achieving compatibility between compact size and light weight and high output has not been achieved. In particular, in an ignition coil in which a coil portion including a primary coil, a secondary coil, and an iron core is disposed outside a plug hole, it is difficult to achieve both a reduction in size and weight and an increase in output.

The present invention has been made in view of the above problems, and achieves a reduction in the size and weight of the ignition coil, and at the same time, achieves high output for reliably igniting even in a severe combustion state, and other vehicle control components even in a narrow engine room. It is an object to provide an ignition coil for an internal combustion engine that is not affected by noise.

In order to solve the above problems, the present invention is configured as follows. That is, a primary coil in which a primary winding is wound around a primary bobbin, a secondary coil in which a secondary winding is wound around a secondary bobbin, and an outer peripheral iron core are sequentially provided on the outer periphery of the central iron core. In the ignition coil for an internal combustion engine that supplies a high voltage generated from the coil portion to the ignition plug, the coil portion is formed of an insulating resin that constitutes a high-pressure tower side on a surface facing the ignition plug. And a second case molded from a magnetic material disposed on the opposite side of the surface facing the spark plug of the first case, and the inner peripheral surface of the second case is The internal combustion engine ignition coil is characterized in that it is in surface contact with the outer peripheral surface of the outer peripheral iron core, and the first case and the second case are filled with a thermosetting mold resin.

In the above configuration, the second case may form a flange that is fixed to the engine block. The first and second cases may be connected by press-fitting, or the first and second cases may be connected by welding. Furthermore, the first and second cases may have a configuration in which an opening surface for filling the mold resin is formed on the same surface as a surface including a connector for supplying a power supply voltage to the primary coil. The first and second cases may be configured such that an opening surface that fills the mold resin is formed on a surface facing the high-pressure tower forming surface.

As described above, the first case molded from the insulating resin constituting the high-pressure tower side on the surface facing the spark plug, and the magnetic material disposed on the opposite side of the surface facing the spark plug of the first case The coil part is accommodated by the second case molded from the inner surface, the inner peripheral surface of the second case is in surface contact with the outer peripheral surface of the outer peripheral iron core, and is thermoset in the first case and the second case. By filling the mold resin, the size and weight of the ignition coil can be reduced, and it is possible to achieve high output to ensure ignition even under severe combustion conditions. An ignition coil for an internal combustion engine that is not affected by noise can be realized.

1 is a perspective view of an ignition coil according to a first embodiment of the present invention. The assembly drawing of the ignition coil of Example 1 is shown. The figure which looked at the 2nd case of the ignition coil of Example 1 from the back side is shown. The upper surface sectional view of the ignition coil of Example 1 is shown. Sectional drawing of the ignition device for internal combustion engines of patent document 1 is shown.

An example showing the embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a perspective view of an ignition coil according to a first embodiment of the present invention, FIG. 2 is an assembly view of the ignition coil, FIG. 3 is a diagram of a second case of the ignition coil viewed from the back side, and FIG. 4 is a cross-sectional top view of FIG.

1 and 2, the ignition coil 100 includes an iron core having a closed magnetic circuit structure by combining an I-shaped central iron core formed by laminating about 30 silicon steel plates and a substantially circular outer peripheral iron core 32; A primary coil 10 in which a primary winding is wound about 100 turns on the outer periphery of a primary bobbin formed of resin on the outer periphery of the central iron core, and a secondary bobbin formed of resin on the outer periphery of the primary coil 10 The secondary coil 20 is formed by winding a secondary winding about 8000 to 15000 turns on the outer periphery. The coil portion is housed in a box-shaped case by combining a first case 40 molded from an insulating resin and a second case 50 molded from a magnetic material. Further, the first case 40 is disposed with the spark plug side disposed in the plug hole formed in the upper part of the engine with respect to the coil portion as a bottom surface, and the second case 50 is disposed with respect to the coil portion. The side opposite to the spark plug is disposed as an upper surface.

The first case 40 has a shape that covers one surface in the spark plug direction with respect to the six outer peripheral surfaces of the coil portion, and the second case 50 corresponds to the six outer peripheral surfaces of the coil portion. Thus, the first case 40 is arranged to cover five surfaces excluding the arrangement surface. Further, a high-pressure tower 42 is formed on the outer bottom surface of the first case 40 so as to protrude from the plug hole toward the spark plug.

The first case 40 is formed with a convex portion 40a at a position relative to the connection portion with the second case 50, and the second case 50 is provided with the convex portion 40a of the first case 40. A recess 50a is formed at a position relative to the connecting portion. Further, the convex portion 40a and the concave portion 50a are connected and fixed by welding when the first and second cases 40 and 50 are assembled.

Further, a substantially triangular prism-shaped mounting flange 52 for mounting the ignition coil 100 to the engine block is formed on the side surface of the second case 50, and the flange 52 is bolted with respect to the axial direction of the high-pressure tower 42. By being penetrated, it is fixed in surface contact with the engine block. Further, a resin-molded connector 60 is attached to the side surface of the second case 50 facing the flange 52 formation surface.

Further, an opening 50b for filling an insulating mold resin is formed in the assembled ignition coil 100 on the same surface as the connector 60 of the second case 50. Further, an igniter 70 composed of a switching element for supplying an ignition signal to the primary coil 10 is accommodated in the vicinity of the connector 60 mounted on the second case 50.

The coil unit and the igniter 70 are electrically connected to a battery or an ECU via the connector 60, respectively. Further, in the ignition coil 100, the coil portion and the igniter 70 are electrically insulated and physically fixed by the molding resin filled from the opening 50b.

In FIG. 2, the assembly procedure of the ignition coil 100 will be described. First, the coil part assembled from the primary coil 10, the secondary coil 20, the central iron core, and the outer peripheral iron core 32 is accommodated in the first case 40 in the direction of arrow A in the figure. Next, the second case 50 to which the connector 60 and the igniter 70 are connected and fixed is put on the coil case and the first case 40 in the direction of arrow B in the figure. Finally, the mold resin is filled from the opening 50b, and the coil part and the igniter 70 are electrically insulated and physically fixed.

3 or 4, the side surface of the second case 50 is formed along the curved shape of the outer peripheral iron core 32, and the inner peripheral surface 50 c of the second case 50 is the outer peripheral surface of the outer peripheral iron core 32. Surface contact with 32a. Further, a magnetic path having a cross-sectional area including the second case 50 is formed on the outer peripheral iron core 32 with respect to the magnetic path in the M direction of the outer peripheral iron core 32.

With the above configuration, the inner peripheral surface 50c of the second case 50 formed of a magnetic material is brought into surface contact with the outer peripheral surface 32a of the outer peripheral iron core 32, thereby ensuring the magnetic flux of the outer peripheral iron core 32. However, the dimension of the ignition coil 100 in the L direction (described in FIG. 4) is suppressed, and the size and weight can be reduced. Further, the second case 50 formed of a magnetic material has a shape that covers five surfaces excluding the first case 40 placement surface with respect to the six outer peripheral surfaces of the coil portion, so that the coil portion can be Noise from other in-vehicle control components can be blocked. Further, the first case 40 is disposed with the ignition plug side of the ignition coil 100 as a bottom surface, and forms the high-voltage tower 42 so that a high voltage from the secondary coil 20 is applied to the second case 50. To prevent leaks.

In addition, the second case 50 is formed with the flange 52, and the inner peripheral surface 50c of the second case 50 is in surface contact with the outer peripheral surface 32a of the outer peripheral iron core 32, thereby Heat generated in the iron core 32 can be released to the engine block via the flange 52.

As a modification of the first embodiment, a magnetic material such as an amorphous alloy or permalloy may be used as the magnetic material constituting the second case 50. Further, the shape of the outer peripheral iron core 32 can be arbitrarily changed according to the design circumstances as long as the outer peripheral surface 32a of the outer peripheral iron core 32 is in surface contact with the inner peripheral surface 50a of the second case 50. Also good. Furthermore, the shape of the second case 50 may be changed to an arbitrary shape depending on design circumstances, such as a thickness necessary for securing the magnetic flux of the outer peripheral iron core 32.

Further, the flange 42 may be formed at any position as long as the strength can be maintained when the ignition coil 100 is fixed. Further, although the high-pressure tower 42 is formed in the first case 40, it may be formed as a separate part.

Further, the first and second cases 40, 50 may be configured to connect the convex portion 40a formed in the first case 40 and the concave portion 50a formed in the second case 50 by press-fitting. Good. Furthermore, although the opening 50b for filling the mold resin is formed on the same surface as the connector 60 of the second case 50, it is formed on the surface of the second case 50 facing the high-pressure tower 42. May be.

10: 1 primary coil
20: Secondary coil
32: Outer iron core
32a: Outer surface
40: First case
40a: Convex part
42: High-pressure tower
50: Second case
50a: recess
50b: Opening
50c: Inner peripheral surface
52: Flange
60: Connector
70: Igniter
100: Ignition coil

Claims (6)

A coil having a primary coil in which a primary winding is wound around a primary bobbin, a secondary coil in which a secondary winding is wound around a secondary bobbin, and an outer peripheral iron core in order on the outer periphery of the central iron core In the internal combustion engine ignition coil that supplies the high voltage generated from the part to the ignition plug,
The coil portion is disposed on a surface opposite to the spark plug, on a side opposite to the surface facing the spark plug of the first case, and a first case molded from an insulating resin constituting the high-voltage tower side. And a second case molded from a magnetic material to be
The inner peripheral surface of the second case is in surface contact with the outer peripheral surface of the outer peripheral iron core,
An ignition coil for an internal combustion engine, wherein the first case and the second case are filled with a thermosetting mold resin. The ignition coil for an internal combustion engine according to claim 1, wherein the second case forms a flange that is fixed to the engine block. The internal combustion engine ignition coil according to claim 1 or 2, wherein the first and second cases are connected by press-fitting. The internal combustion engine ignition coil according to claim 1 or 2, wherein the first and second cases are connected by welding. The first and second cases are characterized in that an opening for filling the mold resin is formed on the same surface as a surface having a connector for supplying a power supply voltage to the primary coil. 5. The ignition coil for an internal combustion engine according to any one of 4. 5. The first and second cases according to claim 1, wherein an opening for filling the mold resin is formed on a surface facing the high-pressure tower forming surface. 6. Ignition coil for internal combustion engines.

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