JPS59195812A - Ignition coil for internal combustion engine - Google Patents

Abstract

PURPOSE:To obtain electrical characteristics equal to or higher than those of an ignition coil with an iron core and reduce the weight by a method wherein a primary bobbin and a case are formed by molding of electrically insulating resin filled with electrically insulating magnetic powder. CONSTITUTION:A primary bobbin 1 is formed by molding of electrically insulating resin filled with magnetic powder such as ferrite. The primary bobbin 1 is composed of a hollow drum portion 13, flanges 11, 14 provided to both ends of the drum portion 13 and a primary terminal fixing protrusion 12 provided to the end of one flange 11. The outside diameter of the flange 11 is such that a gap of 0.5- 3mm. is formed between the inside circumference of a case and the flange 11. A case 3 is formed by molding of the resin which is similar to that used for the primary bobbin 1 and filled with ferrite powder. The case 3 is composed of a shaft 31 arranged to the direction of the center axis, a cylinder 32 provided to the outside circumference, a disc-shape end plane 30 which connects the shaft 31 and the cylinder 32, a protrusion 33 for fitting to the body provided to the outside of the shaft core of the end plane 30 and a high potential cord terminating cylinder 34 provided to the outside and close to the circumference of the end plane 30 and all these parts are molded solidly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of an ignition coil in which a primary bobbin and a case made of electrically insulating resin are filled with magnetic powder having electrically insulating properties.

Conventionally, a primary bobbin was provided outside the laminated iron core, and the
Next, since the coil was S wired to the bobbin, it was heavy,
The outer diameter was also large.

Therefore, the present invention has developed an ignition coil that is equivalent to or higher than the conventional iron-core ignition coil by molding the secondary bobbin and case with an electrically insulating resin filled with electrically insulating magnetic powder (ferrite, etc.). The purpose is to have electrical performance and to reduce the weight by eliminating the need for a heavy iron core.

Furthermore, since the weight is reduced, if a protrusion for attaching to the vehicle body is provided on one wheel of the case, it becomes possible to attach at two locations.

The present invention will be explained below with reference to embodiments shown in the drawings.

1 is a primary bobbin made of electrically insulating resin filled with magnetic powder such as ferrite, and has a hollow body part 1.
3, a collar portion 11°14 provided at both ends thereof, and a protrusion portion 12 for fixing the primary terminal provided on the end face of one tail portion 11, and the collar portion 11 is 0.5 in.
The outer diameter dimensions create a gap of ~3. 3 is a case made of resin filled with ferrite powder similar to that of the primary bobbin 1, and a shaft portion 3 is arranged in the direction of the central axis.
, a cylindrical portion 32 provided on the outer diameter, a disk-shaped end surface portion 3o connecting the shaft portion 31 and the cylindrical portion 32, and an axial center of the end surface portion 30 (a cylindrical portion 32 provided on the side The protruding portion 33 and the high-voltage cord insertion cylinder portion 34 provided near the outer diameter (side) of the end surface portion 30 are integrally molded. The dimensions are determined so as to fit with a clearance in the section 13. 4 is a primary winding wound on the secondary bobbin 1, 6 is arranged on the outer diameter of the secondary bobbin 1, and a plurality of windings are arranged in the axial direction. This is the secondary bobbin that makes the groove.

Reference numeral 5 denotes a secondary winding that is sequentially wound in each winding groove of the secondary pobbin 6.

Reference numeral 7 denotes a primary terminal fixed by a protrusion 12 of the collar portion 11 of the secondary pobbin 1.

Reference numeral 8 denotes a high-pressure terminal that is press-fitted and fixed to the high-pressure side end surface of the secondary bobbin 6 and whose tip protrudes into the cylindrical portion 34 of the case 3.

A high voltage cord 9 is inserted and fixed into the cylindrical portion 34 of the case 3, and its core wire 91 is electrically connected to the high voltage terminal 8. Reference numeral 2 denotes a resin for insulating and fixing the coils 4 and 5 housed in the space 3, and epoxy resin filled with an inorganic filler is mainly used.

The bobbin 1 and the case 3 are preferably made of a thermoplastic resin (eg, polybutylene terephthalate, nylon, etc.) filled with magnetic powder such as ferrite at a weight ratio of 1:1.

In the above structure, the primary bobbin 1 and the case 3 are made of an electrically insulating resin filled with magnetic powder such as ferrite, and the flange 1 of the secondary bobbin 1 on the opening side of the case 3 is
1 has an outer diameter dimension that creates a gap of 0.5 to 3IIll with the cylindrical part 32 of the case 3, and the hollow body part 13 at the center of the next pobbin 1 and the shaft part 31 of the case 3 are fitted and fixed. As a result, an almost closed magnetic circuit can be created between the primary bobbin 1 made of resin filled with magnetic powder and the case 3.
A sufficient secondary voltage can be obtained without using an iron core as in the conventional case, and a heavy iron core is not required, so the weight can be reduced by about 25% compared to the conventional case. Furthermore, since the weight is reduced, it is possible to withstand sufficient fixing strength by simply fixing the vehicle body mounting protrusion 33 integrally provided at one end of the case 3, thereby improving the ease of mounting. Can be done.

The magnetic powder filled in the case 3 is preferably a highly insulating magnetic powder, and the volume fixed resistance in the resin-formed state is I.
X1'010Ω・cm or more is good.

[Brief explanation of drawings]

The figure is a longitudinal sectional view showing an embodiment of the device of the present invention. 1... - next bobbin, 2... resin, 3... case,
4:...-secondary winding, 5...secondary winding, 11.14...
-Brim part, 13...Body part, 30...End face part, 31-
... Shaft part, 32... Cylindrical part. Representative Patent Attorney Takashi Okabe

Claims (1)

[Claims] It has a hollow body and a flange formed at both ends of the body, and the flange on the end face on the case opening side is 0.5 to 3 mm larger than the inner diameter of the case.
A primary bobbin with an outer diameter dimension having a gap of I+ll11, a shaft portion arranged in the direction of the central axis, a cylindrical portion provided on the outer diameter of this shaft portion, and an end face portion connecting the shaft portion and the cylindrical portion. An ignition coil for an internal combustion engine, the ignition coil being molded from an electrically insulating resin filled with magnetic powder.