JP5956947B2 - Ignition coil for internal combustion engine - Google Patents

Description

The present invention relates to an ignition coil that supplies a high voltage to an ignition plug of an internal combustion engine, and more particularly to an ignition coil that is disposed immediately above the ignition plug and fixed to a block of the internal combustion engine.

2. Description of the Related Art Conventionally, an internal combustion engine ignition coil is individually provided for an ignition plug provided in each cylinder and is fixed to an engine block with a mounting bolt. In particular, for the purpose of high energy or fuel efficiency in recent times, a technique has been generalized in which one ignition coil is arranged in one spark plug and ignition energy and ignition timing are controlled independently for each cylinder. Similarly, a so-called stick-type ignition coil that accommodates a primary coil, a secondary coil, an iron core, and the like in a plug hole of an engine that accommodates a conventional ignition plug has been mainstream. Larger copper wires and iron cores are inevitable, and each coil iron core of the ignition coil has been placed outside the plug hole, and after being housed in the case, it has shifted to a type that is bolted to the engine block directly above the ignition plug. ing.

As an example of such an ignition coil, an ignition coil disclosed in Japanese Patent Application Laid-Open No. 2004-241621 (Patent Document 1) has been proposed. FIG. 4 is a cross-sectional view of the ignition coil disclosed in Patent Document 1, and FIG. 5 is a top view of the ignition coil mounted on the in-line 4-cylinder engine. The structure of the ignition coil in Patent Document 1 will be described as follows. The case 50 disposed immediately above the plug hole has an upper surface opened, and the side surface of the case 50 is connected to a battery and from an external control device. A connector 60 for transmitting and receiving signals is disposed, and a mounting flange 52 for mounting the ignition coil 100 to the engine block 110 is formed on the side surface opposite to the side surface on which the connector 60 is disposed.

Further, in the case 50, a primary bobbin 10 disposed on the outer periphery of the central iron core 30, a primary winding 12 wound around the primary bobbin 10, and a secondary bobbin disposed on the outer periphery. A coil body in which a secondary winding 22 wound around the secondary bobbin 20 and an outer peripheral iron core 32 that forms a closed magnetic path in combination with the central iron core 30 is accommodated; An igniter 40 mainly composed of a switching element is disposed in the gap between the connector 60 and the coil body. The coil body and the igniter 40 are buried in the mold resin 70 injected into the case 50, and the mold resin It is integrated with the case 50 by 70 thermosetting.

As a characteristic configuration in the above, the arrangement position of the igniter 40 is provided close to the connector 60 for the convenience of routing the signal line from the connector 60. That is, the igniter 40 that is connected to the battery and the signal line from the outside and also has a connection path to the primary winding 12 and the secondary winding 22 in the ignition coil 100 has the shortest distance for the convenience of this input / output path. Since it is convenient to arrange between the connector 60 and the coil body that can be secured, such a configuration has been conventionally selected.

JP 2004-241621 A

However, the following problems occur in the conventional ignition coil. That is, further downsizing and weight reduction are desired as recent automobile design issues, and in accordance with this, downsizing and weight reduction of the engine body or peripheral devices are also desired. In particular, the ignition coil is mounted on the cylinder head of the engine, and the ignition coil structure outside the plug hole is enlarged with the switching from the stick coil to the ignition coil arranged outside the plug hole.

Due to this increase in size, it becomes an ignition coil that cannot be mounted on the engine or affects assembly and maintenance even if it can be mounted, and it is difficult to design an ignition coil that satisfies the required high output and is excellent in engine mountability. It has become a thing. Although it is ideal to reduce the length of the ignition coil in order to improve the mounting capability of the ignition coil in the engine, it is difficult to change the dimensions of the coil body due to electromagnetic characteristics. Conventionally, as shown in FIG. It is mounted on the cylinder head by rotating the spark plug electrode as an axis. For this reason, when the terminal to be inserted into and removed from the connector is inserted and removed, the terminal interferes with the engine block to cause deterioration in workability, and the degree of freedom in mounting the ignition coil is lost.

The present invention has been made in view of the above problems, and an object thereof is to provide an ignition coil that maintains a high output and is excellent in mountability to an engine.

In order to solve the above problems, the present invention has the following configuration of an ignition coil for an internal combustion engine. That is, an iron core composed of a central iron core and an outer peripheral iron core, 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, An igniter that supplies an ignition signal to the primary coil, a case that houses the iron core, the primary coil, and the secondary coil, and a mounting flange that is formed on the case that is fixed to a mounting portion that is formed on the engine block It equipped with a door,
The igniter is accommodated between the mounting flange and the outer peripheral iron core in the case.

In the above configuration, the igniter may be disposed in the case so as to be buried in the mounting flange. The case includes a connector for electrically connecting the primary coil, the secondary coil, and the igniter to the outside, and an igniter terminal for electrically connecting the connector and the igniter. It is good also as a structure arrange | positioned along the said internal peripheral surface, and the said igniter terminal may be buried and arrange | positioned at the said internal peripheral surface.

The mounting flange may include a metal mounting bush for fixing to the engine block with screws or bolts, and the mounting bush may be in surface contact with the igniter. Further, the mounting bush may form a contact portion that performs heat transfer from the igniter, or the mounting bush and the igniter may be brought into contact with an inclusion having thermal conductivity.

The ignition coil having the above configuration can reduce the length of the ignition coil as a whole while maintaining the electromagnetic characteristics of the coil body structure as it is in the conventional size. In addition, the terminal connected to the connector can be easily removed.

Further, by disposing the igniter in the vicinity of the mounting flange, the heat generated in the igniter is transmitted to the mounting bolt, whereby the thermal influence of the ignition coil can be reduced and the reliability of the ignition coil is improved.

1 is a sectional view of an ignition coil according to a first embodiment of the present invention. The upper surface sectional view of the ignition coil of Example 1 is shown. 1 is a top view of an ignition coil mounted on an in-line four-cylinder engine according to Embodiment 1. FIG. Sectional drawing of the ignition coil of patent document 1 is shown. The top view of the ignition coil with which the in-line 4 cylinder engine of patent document 1 was mounted | worn is shown.

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

FIG. 1 is a sectional view of an ignition coil according to a first embodiment of the present invention, FIG. 2 is a top sectional view of the ignition coil, and FIG. 3 is a top view of an ignition coil mounted on an in-line four-cylinder engine. .

1 and 2, the case 50 forming the outer shape of the ignition coil 100 is formed in a box shape having an opening on the upper surface in the vertical direction made of an insulating resin. Further, a substantially triangular prism-shaped mounting flange 52 for mounting the ignition coil 100 to the engine block 110 is formed on the side surface of the case 50, and a metal mounting bush 52a is disposed on the mounting flange 52 by insert molding. Has been. Further, the mounting flange 52 is fixed in surface contact with the engine block 110 by passing through the mounting bush 52a with a bolt from the vertical direction.

The ignition coil 100 includes an iron core having a closed magnetic circuit structure by combining an I-shaped central iron core 30 formed by laminating about 30 silicon steel plates and a B-shaped outer peripheral iron core 32, and A primary coil in which a primary winding 12 is wound around the outer periphery of a primary bobbin 10 formed of resin on the outer periphery of the central iron core 30 and a secondary bobbin 20 formed of resin on the outer periphery of the primary coil. A coil portion comprising a secondary coil having a secondary winding 22 wound about 8000 to 15000 turns around the outer periphery thereof is housed in the case 50. Further, a magnet 34 for generating a magnetic flux in a direction opposite to the magnetic flux generated in the primary coil in one of the connection surfaces of the central iron core 30 and the outer peripheral iron core 32 is provided.

Further, a high voltage tower 54 is formed on the outer bottom surface of the case 50 so as to protrude into a plug hole formed in the upper part of the engine, and the high voltage tower 54 ignites a secondary voltage output from the secondary coil. Even plugs are supplied. Further, a connector 60 is attached to the side surface of the case 50, and the connector 60 is disposed on the side surface of the case 50 facing the mounting flange 52.

In addition, the connector 60 has a structure that is inclined toward the opening surface side of the case 50 from the mounting portion with the case 50 toward the distal end connected to the external terminal.

An igniter 40 composed of a switching element for supplying an ignition signal to the primary coil is accommodated in the case 50 on the same side as the mounting flange 52. Further, the igniter 40 is disposed so as to be buried from the inside of the case 50 toward the mounting flange 52 side.

The igniter 40 is in surface contact with a contact portion 52b formed on the mounting bush 52a. Further, the igniter 40 is provided with an igniter terminal 42 for electrical connection with the terminal of the connector 60, and is arranged along the side surface in the case 50.

The coil unit and the igniter 40 are electrically connected to the battery or the ECU via the connector 60, respectively. Further, the connector 60 is provided with a terminal for connecting the connector 60 to the high voltage side of the primary coil and the low voltage side of the primary and secondary coils on the connector 60 arrangement side on the inner surface of the case 50. Electrically connected.

The primary coil and the igniter 40 are electrically connected by a terminal on the side of the case 50 where the mounting flange 52 is formed. Further, the case 50 is filled with a mold resin 70 for realizing electrical insulation and physical fixation of the coil part and the igniter 40, and the coil part accommodating part of the case 50 is disposed outside the plug hole. Installed.

With the above configuration, the igniter 40 is accommodated in the case 50 on the same surface side as the mounting flange 52, and the igniter 40 is embedded in the mounting flange 52 side from the case 50 so as to form a coil. The length of the ignition coil 100 as a whole can be shortened while maintaining the electromagnetic characteristics as the dimensions of the body structure as before, so the degree of freedom in positioning in the rotational direction can be increased when mounting to the engine block 110, and The terminal connected to the connector 60 can be easily removed.

That is, when the ignition coil 100 is disposed in the engine block 110 for each cylinder 120 of a four-cylinder engine, as shown in FIG. 3, the electrode of the ignition plug is fixed so that the axis of the central iron 30 is oriented. Since the engine blocks 110 can be arranged in the same direction, it is not necessary to process the engine block 110 in consideration of interference when the terminals connected to the connector 60 are removed.

Further, the igniter 40 is in surface contact with the contact portion 52b formed on the mounting bush 52a, thereby transferring the heat generated in the igniter 40 to the mounting bolt and reducing the thermal influence of the ignition coil 100. Thus, the reliability of the ignition coil 100 is improved.

As a modification of the first embodiment, if the igniter 40 is arranged in the case 50 on the same plane as the mounting flange 52, the case where the mounting flange 52 and the connector 60 are opposed to each other is provided. It is good also as a structure other than arrange | positioning on 50 side surfaces. Further, although the igniter 40 is disposed so as to be buried from the inside of the case 50 to the mounting flange 52 side, the igniter 40 is disposed in a housing portion in which an opening surface of the case 50 is extended to the mounting flange 52 side. Also good. Further, the igniter terminal 42 may be arranged buried in the inner peripheral surface of the case 50.

Further, the igniter 40 may be in direct contact with the mounting bush 52a to transmit heat generated in the igniter 40 to the mounting bolt to reduce the thermal influence of the ignition coil 100. Furthermore, the shape of the contact portion 52b that makes surface contact with the igniter 40 may be changed to a structure that can dissipate heat more efficiently depending on design circumstances.

Further, for example, an arrangement having high thermal conductivity such as polyethylene or nylon resin is disposed between the mounting bush 52a and the igniter 40 to transmit heat generated in the igniter 40 to the mounting bolt. Also good.

10: 1 primary bobbin
12: Primary winding
20: Secondary bobbin
22: Secondary winding
30: Central iron core
32: Outer iron core
34: Magnet
40: Igniter
42: Igniter terminal
50: Case
52: Mounting flange
52a: Mounting bush
52b: Contact area
54: High pressure tower
60: Connector
70: Mold resin
100: Ignition coil

Claims (7)

An iron core comprising a central iron core and an outer iron core, 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 the primary An igniter that supplies an ignition signal to the coil, a case that houses the iron core, the primary coil, and the secondary coil, a mounting flange that is formed on the case that is fixed to a mounting portion that is formed on the engine block, the ignition coil for an internal combustion engine having a
The igniter of the said casing, the mounting flange and the outer peripheral ignition coil, characterized in that it is housed between the iron core.   The ignition coil for an internal combustion engine according to claim 1, wherein the igniter is disposed in the case so as to be buried in the mounting flange. The case includes a connector for electrically connecting the primary coil, the secondary coil, and the igniter to the outside.
The ignition coil for an internal combustion engine according to claim 1 or 2, wherein an igniter terminal for electrically connecting the connector and the igniter is disposed along the inner peripheral surface of the case.   The ignition coil for an internal combustion engine according to claim 3, wherein the igniter terminal is buried in the inner peripheral surface of the case. The mounting flange includes a metal mounting bush for fixing to the engine block with screws or bolts,
The ignition coil for an internal combustion engine according to any one of claims 1 to 4, wherein the mounting bush is in surface contact with the igniter.   6. The ignition coil for an internal combustion engine according to claim 5, wherein the mounting bush forms a contact portion that performs heat transfer from the igniter.   6. The ignition coil for an internal combustion engine according to claim 5, wherein the mounting bush and the igniter are brought into contact with each other by inclusions having thermal conductivity.

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