JPS60192313A - Core-integrating mold type ignition coil - Google Patents

Abstract

PURPOSE:To prevent generation of cracks of resin supplied at the corners of core by setting the surface for supplying resin into the case lower than the upper surface of closed magnetic path core and extruding a part covered with elastomer of core from the resin. CONSTITUTION:A T-shape core 10 and a U-shape core 15 are combined into the shape squirish 8, forming a closed magnetic path core. The entire part of external circumference except for the joint with the U-shape core 15 of the T- shape core 10 is covered with thin elastomer 11 consisting of thermoplastic resin and when this elastomer 11 is molded, the primary spool 1A is integrally molded on the T-shape core 10 by the thermoplastic resin. The primary coil 2 is wound on this T-shape core 10, a secondary coil 4 is arranged at the external circumference thereof, these parts are housed in a cup-shape resin case 6 which is integrally molded with the core 15 along the shape of internal diameter of the U-shape core 15, inside of this case 6 impregnated with epoxy resin. 7. Moreover height of resin surface of this epoxy resin 7 is set lower than the upper surface of T-shape core and the upper part covered with the elastomer 11 of T-shape core 10 is extruded from the epoxy resin 7 in the case 6.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the structure of a core-integrated molded ignition coil used in an ignition device for an internal combustion engine.

(Prior art) The conventional structure is as shown in Figs. The secondary coil 4, the closed magnetic circuit core 5, etc. are housed in a case 6, and are cast and impregnated with an epoxy resin 7.The epoxy resin 7 on the upper surface of the upper E-shaped core constituting the closed magnetic circuit core 5 forms the core. By covering the entire 5, 2
Next, insulation between the high voltage terminal 8 and the core 5 was maintained. In addition, core 5 is made of thermoplastic elastomer 7 as a heat shock countermeasure.
9, which had the disadvantage of being large and expensive.

(Object of the Invention) In order to eliminate the above-mentioned drawbacks, the present invention covers at least the upper part of the core with an elastomer, and furthermore, the upper surface of a casting resin such as epoxy resin is set lower than the upper surface of the core. By configuring the covered part to protrude from the casting resin, insulation between the secondary high voltage terminal and the core can be maintained without covering the top surface of the core with the casting resin, making it possible to create a small and low-cost ignition coil. The purpose is to do something.

(2) (Example) The present invention will be described below with reference to embodiments shown in the drawings.

In FIG. 3 and FIG. 4, a T-shaped core 10 and a U-shaped core 15 are combined in a zigzag shape to form a closed magnetic circuit core. The entire outer periphery of the T-shaped core 10 except for the joint with the U-shaped core 15 is thinly coated with an elastomer 11 made of thermoplastic resin or the like, and when the elastomer 11 is molded, the primary spool IA is made of thermoplastic resin. T-type core 1
It is integrally molded on the 0. A primary coil 2 is wound on the primary spool IA of this T-shaped core 10, and two
A secondary coil 4 wound on the secondary spool 3 is arranged, and a high voltage terminal 8 is fixed to the upper end of the secondary spool 3. Each of these parts is housed in a cup-shaped resin case 6 integrally molded with the U-shaped core 15 along the inner diameter shape of the U-shaped core 15, and an epoxy resin 7 is cast and impregnated into the case 6. Furthermore, the height of the resin surface of the epoxy resin 7 is set to be lower than the upper surface of the T-shaped core, so that the upper (3) portion of the T-shaped core 10 covered with the elastomer 11 is exposed to the epoxy resin inside the case 6. It is more prominent than 7. Further, the upper part of the secondary high voltage terminal 8 is also made to protrude from the upper opening end of the epoxy resin 8 and the case 6.

In the conventional core integrally molded ignition coil, the first
As shown in the figure, by completely filling the core 5 with epoxy resin 7, insulation between the high voltage terminal 8 and the core 5 is maintained. As a countermeasure to this problem, the core 5 was covered with thermoplastic elastomer 9, and the thickness of the upper surface of the core 5 of the epoxy resin 7 was ensured to be at least 3 mm, which was disadvantageous in terms of size and cost. It had become.

In this embodiment, by setting the surface of the epoxy resin 7 lower than the upper surface of the core 10, it is possible to reduce the size of the coil and to prevent cranking from the corner portion of the core 10 of the epoxy resin 7.

Here, when molding the primary spool IA with thermoplastic resin or the like, it is possible to simultaneously cover the upper surface of the T-shaped core 10 with the elastomer (4) 11, and thereby,
Insulation between the high voltage terminal 8 and the core 10 can also be maintained. As for the effect of the physique, it is possible to reduce the size by about 7 meters in the height direction. In addition, in the case 6 that is integrally molded with the U-shaped core 15, not only the outer part of the tJ-shaped cocoa 6 but also the inner part is coated with the resin forming the case 6, so that the epoxy resin 7 and the core 15 are directly connected to each other. Cod resistance 7 without touching
Improves resilience.

The above explanation is about the T+U type core, but also in the configuration of the E+E type core, ■→-E type core, by setting the epoxy resin surface lower than the top surface of the core,
A similar effect can be obtained. (However, the core and the primary spool need to be molded separately.) Furthermore, the core 15 and the case 6 do not necessarily need to be molded integrally.

(Effects of the Invention) As described above, in the present invention, the injection surface of the casting resin injected into the case is set lower than the upper surface (5) of the closed magnetic circuit core, and the portion of the core covered with the elastomer is Because it protrudes from the casting resin, the elastomer can maintain insulation between the core and the secondary high-voltage terminal without covering the top surface of the core with casting resin, making it possible to provide a compact and low-cost ignition coil. It has excellent effects.

[Brief explanation of the drawing]

1 and 2 are a side longitudinal sectional view and a front longitudinal sectional view showing a conventional coil, and FIGS. 3 and 4 are a side longitudinal sectional view and a front longitudinal sectional view showing an embodiment of the coil of the present invention. . 2... Primary coil, 4... Secondary coil, 6... Case, 7... Epoxy resin forming the casting resin, 8...
Secondary high voltage terminal, 11... Elastomer, 10.15...
・T-shaped core and U-shaped core that make up the closed magnetic circuit core. Representative Patent Attorney Takashi Okabe (6) Figure 1 q Figure 2 Figure 4

Claims (1)

[Claims] A closed magnetic circuit core, a primary and secondary coil attached to the core, an elastomer coated on at least an upper part of the core, a case housing the core and the primary and secondary coils, and a case injected into the case. a cast resin, the injection surface of the cast resin is set lower than the upper surface of the closed magnetic circuit core, and the portion of the core covered with the elastomer protrudes from the cast resin. Molded ignition coil.