JP2000182862A - Ignition coil for engines - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent cracking due to thermal stresses by providing a cracking prevention spacer between a core housing and a secondary coil bobbin. SOLUTION: A core housing 3 is an insert molding of a rod-like core 2 so as to project in a case, a primary and secondary coil bobbins 4, 5 are fitted parallel in the outer side of the core housing 3, an insulative resin is injected in a coil case 1 opened at one end to form a unified body, and a crack stop spacer 11 is provided between the core housing 3 and the secondary coil bobbin 5. This spacer 11 may extend over the entire length of the core housing 3, but here is provided partly near the secondary coil output end wound around the secondary coil bobbin 5 which has a heating quantity to give a comparatively high thermal stress to the surrounding.

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 a resin-molded engine.

[0002]

2. Description of the Related Art Conventionally, an insulating molten resin is injected into a coil case in which a unit composed of a primary coil bobbin, a secondary coil bobbin and a core is incorporated, and the resin is cured to integrally form the whole. In an ignition coil device for an engine, a partition is provided around the unit inside the coil case, and the thermal stress generated by the heat generation of the unit is reduced by the partition so that cracks are generated in the mold resin. (See Japanese Patent Application Laid-Open No. 50-78857).

[0003]

The problem to be solved is that if the mold resin interposed between the coil case and the internal unit is separated by a partition, cracks are formed between the coil case and the internal unit. Although it is possible to prevent the occurrence of cracks, it is not possible to prevent the occurrence of cracks due to the thermal stress that occurs partially in the unit incorporated inside the coil case, and the insulation breakdown occurs in the unit itself and the characteristics are reduced. It will be degraded.

[0004]

According to the present invention, a core accommodating portion into which a dedicated core is insert-molded from the outside is formed to protrude inside the case, and a primary coil bobbin and a secondary coil bobbin are provided around the outer periphery of the core accommodating portion. An ignition coil device for an engine in which an insulating resin is injected into the inside of a coil case, which is mounted so as to be fitted, and which is open on one side, and which is integrally molded as a whole, has a core housing portion and a secondary coil bobbin. Between them, a spacer for preventing the occurrence of cracks is provided to prevent the occurrence of cracks at locations where relatively large thermal stress is likely to occur.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In an ignition coil device for an engine according to the present invention, as shown in FIGS. 1 and 2, a core housing portion 3 into which a dedicated core 2 is insert-molded from the outside is formed so as to protrude inside the case. Insulating resin is injected into the inside of the coil case 1 having an open side and mounted side by side so that the primary coil bobbin 4 and the secondary coil bobbin 5 are fitted around the outer periphery of the core housing portion 3. Are integrally molded.

The output terminal socket 6 is provided in the coil case 1.
Are formed integrally, and when the secondary coil bobbin 5 is mounted in the coil case 1, the secondary output terminal 7 provided on the bobbin side has the terminal pin 8 of the socket projecting into the case. An electrical connection is established by engaging the rear end portion. Also, the primary coil bobbin 4
The primary input terminal 9 of the primary coil and the GN
D terminals 10 are respectively attached.

In the above-mentioned structure, in particular, in the present invention, as shown in FIGS. 3 and 4, a spacer 11 for preventing the occurrence of cracks is provided between the core housing 3 and the secondary coil bobbin 5. It is provided.

The spacer 11 for preventing the occurrence of cracks may be provided over the entire length of the core accommodating portion 3. However, in this case, in particular, a secondary heat generating a large amount of heat and giving a relatively large thermal stress to the periphery is provided. It is partially provided near the output end side of the secondary coil wound around the coil bobbin 5 so as to effectively prevent cracks and reduce the size and weight of parts.

As the spacer 11, for example, when an epoxy-based mold resin is used, a spacer made of a thermoplastic resin such as polypropylene, which has poor affinity with the resin, is used.

As described above, according to the present invention, the spacer 1
1. The mold resin is rejected at the place where cracks are most likely to occur, and the generated thermal stress is effectively suppressed by being buffered by the spacers 11 to cause cracks in the surrounding mold resin portion. Can be prevented.

[0011]

As described above, according to the present invention, the core accommodating portion into which the rod-shaped core is insert-molded from the outside is formed so as to protrude inside the case, and the primary coil bobbin and the secondary coil bobbin are fitted around the outer periphery of the core accommodating portion. In the ignition coil device of the engine, in which an insulating resin is injected into the inside of the coil case with one side open and molded as a whole, it is mounted between the core housing and the secondary coil bobbin. Since the spacer for preventing the occurrence of cracks is provided, there is an advantage that cracks can be effectively prevented from being generated in a portion where relatively large thermal stress is likely to occur.

[Brief description of the drawings]

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

FIG. 2 is a side view of the ignition coil device of the engine in the embodiment.

FIG. 3 is a front sectional view when the upper half surface of the ignition coil device of the engine in the embodiment is cut away.

FIG. 4 is a side sectional view of the ignition coil device of the engine in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coil case 2 Core 3 Core storage part 4 Primary coil bobbin 5 Secondary coil bobbin 11 Spacer

Claims (2)

[Claims] A core accommodating portion into which a dedicated core is insert-molded from the outside is formed so as to protrude inside the case, and a primary coil bobbin and a secondary coil bobbin are fitted around an outer periphery of the core accommodating portion. In an ignition coil device for an engine in which an insulating resin is injected into the inside of a coil case that is open on one side and the whole is integrally formed, a spacer for preventing cracking is provided between the core housing portion and the secondary coil bobbin. An ignition coil device for an engine. 2. The ignition coil device for an engine according to claim 1, wherein a spacer for preventing cracks is partially provided near the output end of the secondary coil wound around the bobbin.