JPH0630305B2 - Ignition coil for internal combustion engine - Google Patents

Description

The present invention relates to an ignition coil for an internal combustion engine.

[Conventional technology]

As shown in FIG. 7, the conventional one has primary and secondary coils 2 and 3 housed in a case 1 having an open end at one end, and is connected to the secondary coil 3 inside the open end of the case 1. The connecting portion 4a of the high-pressure tower 4 is disposed, and the casting resin 5 is injected into the case 1 from the opening end of the case 1 and cured, so that the casting resin 5 connects the connecting portions 4a, 1 of the high-pressure tower 4. The secondary and secondary coils 2 and 3 are enclosed (for example, Nippon Denso Public Technical Report, reference number 34-147, 19).
Published March 15, 1984).

[Problems to be solved by the invention]

However, in the above-mentioned conventional case, the opening end of the case 1 is horizontal with respect to the bottom surface of the case 1, so that when the resin is poured into the case 1, the case bottom may hit a horizontal jig. Since the opening end of the case 1 is kept horizontal and the liquid surface of the casting resin 5 is formed along this opening end to cure the casting resin 5, the high pressure tower 4
There is a problem that the amount of the casting resin 5 on the inner side of the opening end side of the case 1 on the opposite side becomes larger than necessary, and the weight becomes heavy and expensive.

Therefore, the present invention effectively reduces the amount of casting resin used, and achieves weight reduction and cost reduction.

[Means for solving problems]

Therefore, according to the present invention, a case having an open end at one end, primary and secondary coils housed in the case, and
Next, a core forming a magnetic path of the secondary coil, a high-voltage terminal in which a connection portion with the secondary coil is arranged inside the opening end side of the case, a connection portion of the high-voltage terminal and the primary, Ignition for an internal combustion engine, comprising: a casting resin that is injected and cured into the case to enclose a secondary coil, and has a sloped liquid level that is high as it approaches the high-voltage terminal side and gradually decreases as it goes away from the high-voltage terminal side. Coil A coil is provided.

[Action]

As a result, the amount of the casting resin on the inner side of the case opening end side opposite to the high-voltage terminal is reduced by the amount by which the liquid surface of the casting resin is inclined.

〔Example〕

The present invention will be described below with reference to embodiments shown in the drawings. In a first embodiment shown in FIGS. 1 to 3, reference numeral 1 denotes a synthetic resin cup-shaped case, which has an inclined open end at one end thereof, and the higher side of the open end faces the outer peripheral side. A bulging portion 1a is formed to bulge. 2 and 3 are primary and secondary coils housed in the case, and 4 is a high voltage tower that forms a high voltage terminal,
It has a connecting portion 4a connected to the secondary coil 3, and the connecting portion 4a and the end portion on the connecting portion 4a side of the high voltage tower 4 are arranged in the bulging portion 1a on the inner side of the opening end side of the case 1. Has been done. 5 is a casting resin that is injected and cured in the case 1,
The liquid surface 5a is inclined along the opening end of the case 1, and the casting resin 5 allows the primary and secondary coils 2, 3,
The connection part 4a and the end of the high-voltage tower 4 on the connection part 4a side are enclosed. Reference numeral 6 is a closed magnetic circuit core that forms the magnetic paths of the primary and secondary coils 2 and 3, and is constructed by combining two U-shaped core portions in a square shape, and one of the legs has a primary shape. It is arranged at the center of the coil 2, and the other leg is arranged along the outside of a short side wall of the case 1 on the side opposite to the bulging portion 1a, and one leg is primary or secondary. It is encapsulated with a casting resin 5 together with the coils 2 and 3. Reference numeral 7 denotes a primary terminal connected to the primary coil 2, and is arranged and fixed to the inside of the opening end side of the case 1.

In the above-mentioned configuration, as shown in FIG. 1, the opening end of the case 1 serving as a container for casting the casting resin 5 is provided with the connecting portion 4a sufficiently on the side where the high-pressure tower 4 is mounted.
So that it can be covered with, and the opposite side (core 6 side) is an inclined surface that gradually lowers to reduce the extra space as much as possible, and the case 1 is set so that the opening end is horizontal during resin casting. The casting resin 5 is cast while being set at an inclination.

Here, the cast resin 5 has a drop in the liquid level during curing and a variation during manufacturing, and if the high-pressure portion is exposed, reliability is extremely impaired. For this reason, when the resin is cast into a case having a flat open end as shown in FIG. 7, a large amount of unnecessary resin 5 as shown in the figure is provided on the opposite side of the high pressure tower 4. I will be casting,
Further, along with this, the length of the leg portion of the core 6 needs to be increased by the height of the extra resin 5 injected,
This is not the case with the present embodiment. Further, in the present embodiment, as shown in FIG. 3, when the high-voltage tower 4 is mounted so as to face upward, even if the coil is exposed to water, the high-pressure part is still high, and therefore the high-pressure part is not exposed to water. Reliability is improved without accumulating.

As in the second embodiment shown in FIGS. 4 and 5, E
Also in the case of the mold core, the amount of the casting resin can be reduced by making the opening of the case 1 an inclined surface. Further, in this case, the length of the leg portion of the core 6 can be shortened only slightly. Therefore, if only the amount of casting resin is reduced, as in the third embodiment shown in FIG. It is possible to incline only the liquid surface 5a of the casting resin by setting the slant at a predetermined angle and casting.

In the embodiment described above, one leg of the core 6 is sealed in the casting resin casting, but as a hollow case, the casting resin is injected and cured, and then the core is fitted and fixed in the hollow portion of the case. Alternatively, a part of the core may be integrally molded with the case note in advance, and not only the core closed magnetic circuit core but also a single-character open magnetic circuit core may be used.

〔The invention's effect〕

As described above, in the present invention, since the casting resin liquid surface is inclined, the amount of casting resin on the inner side of the case opening end side opposite to the high-voltage terminal is reduced, so that the insulation property of the high-voltage terminal is reduced. There is an excellent effect that the entire weight can be reduced and the cost can be reduced without any loss.

[Brief description of drawings]

1 to 3 are longitudinal sectional views, plan views and rear views showing a first embodiment of the coil of the present invention, and FIGS. 4 and 5 are front views and side views showing a second embodiment of the coil of the present invention. Figure, 6th
FIG. 7 is a front view showing a third embodiment of the coil of the present invention, and FIG. 7 is a vertical sectional view showing a conventional coil. 1 ... Case, 2 ... Primary coil, 3 ... Secondary coil,
4 ... High-voltage tower forming high-voltage terminal, 4a ... Connection part, 5
…… Casting resin, 5a ・ ・ ・ Liquid level, 6 …… Core.

Claims (2)

[Claims] 1. A case having an open end at one end, primary and secondary coils housed in the case, a core forming a magnetic path of the primary and secondary coils, and an open end of the case. A high-voltage terminal in which a connection portion with the secondary coil is arranged on the inner side portion, and a connection portion of the high-voltage terminal and the primary and secondary coils are injected and hardened into the case so as to be enclosed, and the high voltage An ignition coil for an internal combustion engine, comprising: a casting resin having an inclined liquid surface that is higher as it approaches the terminal side and gradually lower as it goes away from the high-voltage terminal side. 2. The ignition coil for an internal combustion engine according to claim 1, wherein the opening end of the case is also inclined along the liquid surface of the casting resin.