JPH0539617Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention relates to a closed magnetic path type ignition coil for igniting and driving an internal combustion engine of an automobile.

<Prior art> It is necessary to provide an air gap between the two iron cores that make up the closed magnetic path of the ignition coil in order to prevent magnetic saturation of the iron core, but this air gap is inserted into the bobbin of the primary coil from each end. If an air gap is formed between the ends of the bobbin insertion legs, the air gap will have a large magnetic resistance, and magnetic flux will be dispersed at the air gap, reducing the efficiency of generating secondary voltage (high voltage).

For this reason, the applicant proposed in Japanese Utility Model Application Publication No. 1-24814 that a secondary coil is fitted outside the primary coil and housed in an insulating case, and an insulating resin is poured into the case and hardened. At the same time, the bobbin insertion legs of two opposing U-shaped iron cores are inserted into the bobbin of the primary coil from each end of the bobbin and butted,
In addition, the other leg of each of the U-shaped cores is arranged to face each other outside the insulating case while maintaining an air gap, thereby minimizing the dispersion of magnetic flux in the coil body, increasing the amount of effective magnetic flux, and increasing the efficiency of secondary voltage generation. By increasing the output voltage (secondary voltage) for the same weight and dimensions,
We proposed that it would be possible to improve the power consumption by 10%, and to reduce the weight by approximately 20% if the output voltage is the same.

<Problems to be solved by the invention> In the conventional example described above, the legs of two opposing U-shaped iron cores are sandwiched between two non-magnetic plates while maintaining an air gap outside the insulating case, and each leg is connected to the above plate with rivets. This is a very time-consuming process.

<Means for solving the problem> Therefore, in the present invention, each of the above-mentioned U-shaped coils is placed outside an insulating case that accommodates the primary coil and the secondary coil fitted outside the primary coil, and fills both coils with insulating resin. An accommodating cylindrical portion into which the other leg of the iron core enters from each end is provided, and the other leg of the iron core is inserted into the accommodating cylindrical portion from each end, and an air gap is formed in the accommodating cylindrical portion. It is.

<Example> In the illustrated example, 1 is a primary coil, 2 is a secondary coil fitted outside the primary coil, 3 is a bottomed case molded from synthetic resin, and 4 is a case cast into the case. 5 and 6 are a pair of U-shaped iron cores forming a closed magnetic circuit, and 7 is an air gap.

Case 3 has an opening at the bottom, and the primary,
When housing both secondary coils concentrically, the above opening is closed with one end of the bobbin 1' of the primary coil, then insulating resin is cast, and both coils 1 and 2 are placed inside the case using hardened insulating resin 4. Bury and fix.

The U-shaped iron cores 5 and 6 have their respective bobbin insertion legs 5a,
6a is inserted into the bobbin 1' of the primary coil from each end, and the ends are abutted against each other in the bobbin. A housing cylinder part 8 is integrally formed outside the side surface of the case 3 in accordance with the present invention. Therefore, each bobbin insertion leg 5a,
6a into the bobbin 1' of the primary coil from each end, insert the other legs 5b and 6b of the U-shaped cores 5 and 6, each of which is slightly shorter than the insertion leg, into the housing cylinder 8. By inserting from the end, an air gap 7 is created in the housing tube 8 between the tips of the legs 5b and 6b.

Bobbin insertion legs 5a, 6a, other legs 5b, 6b
By applying adhesive when inserting both U-shaped cores 5 and 6 to the primary coil bobbin 1',
It can be strongly adhesively fixed to the housing cylinder part 8.

Further, although the interior of the accommodating cylinder portion 8 is penetrated in this embodiment, a partition wall may be integrally provided at a position where the air gap 7 is formed, and the tips of the legs 5b, 6b may abut against the partition wall.

<Effect of the invention> According to the invention, when the bobbin insertion legs 5a and 6a of the pair of U-shaped iron cores are inserted into the bobbin of the primary coil from each end, the other leg 5b forms an air gap outside the case. , 6b provided in the case.
By inserting the ignition coils from each end, the U-shaped iron cores can be easily fixed in opposing positions, significantly improving the productivity of the ignition coil.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of a closed magnetic circuit type ignition coil according to the present invention, FIG. 2 is a side view of FIG. 1 viewed from the left, and FIG. 3 is a perspective view of a case. In the figure, 1 is the primary coil, 1' is its bobbin, and 2
is the secondary coil, 3 is the case, 4 is the insulating resin, 5 and 6 are the U-shaped iron cores, 5a and 6a are the bobbin insertion legs, 5b
and 6b are the other legs, 7 is an air gap, and 8 is a housing tube.

Claims (1)

[Claims for Utility Model Registration] A secondary coil is fitted outside the primary coil and housed in an insulating case, and an insulating resin is cast into the case and hardened, and the bobbin of the primary coil is Insert the bobbin insertion legs of two opposing U-shaped iron cores into the bobbin from each end of the bobbin and butt them together, and the other leg of each U-shaped iron core to face each other outside the insulating case while maintaining an air gap. In the closed magnetic circuit type ignition coil, a housing cylinder part is provided outside the insulating case, into which the other leg of each of the U-shaped cores enters from each end, and the cores are inserted into the housing cylinder part from each end. A closed magnetic path type ignition coil characterized in that the other leg is inserted and an air gap is formed in the housing tube.