JPH09186031A - Ignition coil device of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve output efficiency by providing an elastic member inside a case part, and interposing mold resin between the elastic member and the assembly, after forming the case part in a tubular form by metallic material, and providing 6 slit in its longitudinal direction. SOLUTION: A case 2 wherein an assembly can be put is made of magnetic material such as a conductive silicon steel plate high in permeability, and a slit of about 0.5-1.5mm to form a gap is provided in its longitudinal direction. Then, elastic material 17 such as rubber, elastomer, etc., is provided inside the case 2. This way, the assembly and the elastic member 17 are interposed between the case 2 and the mold resin being injected into it and hardened. Hereby, the output efficiency can be improved, and also cracks can be prevented from occurring in the mold resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition coil device for an open magnetic circuit type engine.

[0002]

2. Description of the Related Art Conventionally, a coil bobbin wound with a secondary coil is coaxially provided outside a coil bobbin wound with a primary coil, and a dedicated core is inserted into the hollow shaft of the coil bobbin on the primary side. Put it in the coil case,
Inject mold resin into the case and mold integrally,
An open magnetic circuit type in which a connector portion for holding an ignition plug is formed in a coil case, and the tip of the ignition plug inserted in the connector portion is brought into contact with a high-voltage terminal protruding inside the connector portion. There is an engine ignition coil device (see Japanese Utility Model Publication No. 4-23296).

[0003]

The problem to be solved is that in the conventional ignition coil device for an open-magnetic-path type engine, a rod-shaped rod is provided in a hollow shaft of a coil bobbin on which a primary coil and a secondary coil are wound. Due to the structure in which the core is inserted, the generated magnetic flux spreads around and is demagnetized by iron loss when passing through parts such as the cylinder block of the engine, resulting in poor output efficiency is there. Therefore, in order to secure a predetermined secondary output voltage, the size must be increased.

Further, there is a problem in that the mold resin interposed between the coil case and the assembly is apt to crack due to thermal stress, and when the crack occurs, a leak discharge is generated there and the mold resin is deteriorated.

[0005]

According to the present invention, an assembly in which a rod-shaped core is inserted into the hollow shaft of a coil bobbin around which a primary coil and a secondary coil are wound is placed in a coil case, and the case In an ignition coil device for an open magnetic circuit type engine in which a mold resin is injected into the inside to integrally mold the ignition coil device, the output efficiency is improved, and the thermal stress intervenes between the coil case and the assembly. In order to prevent cracks from occurring in the molding resin, the case portion in which the assembly is put is formed into a tubular shape with a metal material of high magnetic permeability, and after providing a slit forming a gap in its longitudinal direction, An elastic member is provided inside the case portion, and a mold resin is interposed between the elastic member and the assembly.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, in an ignition coil device for an engine according to the present invention, a cylindrical case 2 is fitted into one opening of the case 2, and the opening is closed. Thus, the coil case 1 is formed by the case 3 in which the tubular small hole 4 is formed in the central portion to be mounted.

Inside the coil case 1, a secondary coil 7 is provided outside a coil bobbin 6 around which a primary coil 5 is wound.
The coil bobbin 8 wound with is coaxially incorporated,
A rod-shaped core 9 is provided in the hollow shaft of the coil bobbin 6 on the primary side.
Is housed therein. Permanent magnets 10 are attached to both ends of the core 9 so that a large change in the amount of magnetic flux can be obtained when the primary current is interrupted.

As shown in FIG. 2, the core 9 is made of a plurality of iron plates having different widths so that the space factor in the hollow shaft of the cylindrical coil bobbin 6 can be increased to improve the magnetic flux generation efficiency. By lamination, the cross section has a substantially circular shape.

A mounting portion 11 for a high-voltage terminal is integrally formed on one of the flanges of the coil bobbin 8 on the secondary side so as to project to the central portion thereof. Further, a contactor 13 for making an electrical connection with the ignition plug 15 is attached to the high-voltage terminal 12 which is attached to the attachment portion 11 by adhesion.

When the assembly consisting of the coil bobbin 6 on the primary side, the coil bobbin 8 on the secondary side, the high voltage terminal 12 and the contact 13 is housed in the coil case 1, the contact 1
With the protruding portion 3 outside the small hole 4, the mounting portion of the high-voltage terminal 12 is press-fitted into the small hole 4, and the assembly is fixed at a predetermined position in the coil case 1. ing.

With the assembly fixed inside the coil case 1, a molding resin is injected from the other opening of the coil case 1 to be integrally molded.

At this time, the permanent magnets 10 provided at both ends of the core 9 are covered so that the resin does not enter the core 9, and a relatively large thermal stress is generated in the longitudinal direction of the core 9. A damper member 14 is provided that absorbs and prevents the surrounding mold resin from cracking.

Further, a plurality of holes 31 are formed in the mounting portion 11 of the high voltage terminal provided in the flange portion of the coil bobbin 8 on the secondary side, and the molding resin is formed from the holes 31 to the coil bobbin 6 on the primary side. A gap is formed between the coil bobbin 8 on the secondary side and the coil bobbin 8 can be fixed between them.

The case 3 also serves as a connector of the spark plug 15, and a plug rubber 16 for holding the spark plug 15 is attached to the tip of the case 3. And
When the spark plug 15 is inserted into the plug rubber 16, the tip of the spark plug 15 comes into contact with the contact 13 to establish an electrical connection.

In such a structure, particularly in the present invention, the case 2 is formed of a magnetic material such as a silicon steel plate having conductivity and a high magnetic permeability, and it has an electromagnetic shield effect and an open magnetic field. The magnetic flux generated in the road type core 9 serves as a side core so that most of the magnetic flux is concentrated in the case 2, and the generated magnetic flux is demagnetized through the cylinder block portion of the surrounding engine to generate the secondary output voltage. We are trying to suppress such a decrease.
In addition, the case 2 has a large heat dissipation effect.

If the length of the case 2 is too short, the spread of the magnetic flux generated in the core 9 becomes large and the magnetic resistance becomes large, and if it is too long, it becomes meaningless. The optimum length is 1 to 1.3 times the length of 9.

In order to suppress eddy current loss, the case 2 has a C-shaped cross section as shown in FIG.
0.5-1.5 mm forming a gap in the longitudinal direction
A slit 33 of a degree is provided.

In the present invention, inside the case 2,
An elastic member 17 such as rubber or elastomer is provided.

By interposing the elastic member 17 between the case 2 and the mold resin injected and solidified therein, the thermal stress due to temperature change is relaxed by the elastic member 17, and the mold is molded. The occurrence of cracks in the resin is effectively prevented.

Therefore, leakage and discharge from the high-voltage portion can be prevented, and the safety and durability can be improved without degrading the mold resin.

A plurality of ribs 30 are formed between the small hole 4 and the side surface of the case 3 in the case 3 to increase the insulation distance between the high voltage terminal 12 fitted in the small hole 4 and the case 2. I am trying.

Further, as shown in FIG. 1, a low voltage terminal socket 18 is fitted in the upper part of the case 2. An igniter 19 is housed inside the socket.

When the low-voltage terminal socket 18 is fitted into the case 2, the elastic member 17 provided inside the case 2 is folded back and the low-voltage terminal socket 18 is fitted into the folded-back portion 29 so that the sealing property is improved. I am trying to increase.

FIG. 4 shows the internal structure of the low-voltage terminal socket 18 when the cap 20 is removed, and FIG. 5 shows the igniter 19 installed in the low-voltage terminal socket 18.

When the mold resin is injected into the coil case 1 from the upper portion of the low voltage terminal socket 18 with the cap 20 removed, the rib 21 provided inside the cap 20 in the low voltage terminal socket 18 has a level L. After injecting the molding resin to the position, the cap 20 is attached. An air vent hole 22 is provided in the cap 20.

A plurality of ribs 21 are formed on the cap 20, and the cap 20 is fixed by the ribs 21, and the thermal stress applied to the molding resin due to the temperature change is dispersed by the plurality of ribs 21 to form an igniter. It is possible to effectively prevent cracks from being generated in the mold resin on the upper part of 19.

As shown in FIG. 1, a seal rubber 24 for embedding the coil case 1 in the cylinder head 23 of the engine is fitted to the lower side of the low voltage terminal socket 18 of the case 2. .

The coil case 1 is attached to the cylinder head 23.
In a state in which is embedded, the ignition coil unit is attached to the cylinder head 23 side by a bolt 26 via a bolt seat 25 formed integrally with the low voltage terminal socket 18.

Further, the seal rubber 24 and the low-voltage terminal socket 18 are connected to each other so as to communicate with each other so that the air in the embedded portion of the coil case 1 in the cylinder head 23 is not warmed and the pressure does not rise. Air vent holes 27 and 28 are formed. The flow of air at that time is shown by an arrow in the figure.

A flange 36 having the same diameter as the cylinder hole 23 is formed around the plug rubber 16 so as to project therefrom.
6 plays a role of a guide when inserting the coil case 1 into the cylinder hole 23, so that the connection with the spark plug 15 can be surely performed. Further, the engine vibration applied to the coil case 1 side through the spark plug 15 is absorbed by the flange 36, and the vibration applied to the electrical connection portion between the contact 13 and the spark plug 15 is suppressed, resulting in durability. Will be improved.

[0031]

As described above, in the engine ignition coil device according to the present invention, the assembly in which the rod-shaped core is inserted into the hollow shaft of the coil bobbin wound with the primary coil and the secondary coil is placed in the coil case. In an ignition coil device for an open magnetic circuit type engine, in which a molding resin is injected into the case to integrally mold the case, a cylinder is made of a high magnetic permeability metal material, and its longitudinal direction Since the assembly is put in a case that has a slit that forms a gap in the core, most of the magnetic flux generated by the core passes through the case part, and it spreads to the surroundings and is demagnetized. Is effectively suppressed, and the output efficiency can be improved.

Further, according to the present invention, since the elastic member is provided inside the case portion and the molding resin is interposed between the elastic member and the assembly, the thermal stress is applied to the elastic member. It is possible to prevent the mold resin that is effectively relaxed by the cracks from occurring in the mold resin interposed between the case portion and the assembly, and a large insulating effect can be obtained, so that the mold resin due to leakage discharge from the coil can be prevented. There is no deterioration, and safety and durability are improved.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing an embodiment of an ignition coil device for engine according to the present invention.

FIG. 2 is a cross-sectional view of the core in the embodiment.

FIG. 3 is a cross-sectional view of a cylindrical case according to the same embodiment.

FIG. 4 is a plan view showing the internal structure of the low voltage terminal socket in the embodiment.

FIG. 5 is a plan view showing a state where an igniter is attached to a low voltage terminal socket.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coil case 2 1st case 3 2nd case 4 Tubular small hole 6 Primary side coil bobbin 8 Secondary side coil bobbin 9 Core 11 High voltage terminal attachment part 12 High voltage terminal 13 Contactor 15 Spark plug 17 Elastic member 18 Low voltage terminal socket 19 Igniter 33 Slit

Claims (1)

[Claims] 1. An assembly in which a rod-shaped core is inserted into a hollow shaft of a coil bobbin wound with a primary coil and a secondary coil is placed in a coil case, and a mold resin is injected into the case to be integrated. In an ignition coil device for an open-magnet type engine, which is designed to be mechanically formed, a case portion in which an assembly is put is formed in a cylindrical shape by a metal material having high magnetic permeability, and a slit is formed in a longitudinal direction thereof. The ignition coil device for an engine, characterized in that an elastic member is provided inside the case portion, and a molding resin is interposed between the elastic member and the assembly.