JP2000216034A - Molded ignition coil for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized ignition coil which can generate high spark energy in high productivity. SOLUTION: This molded ignition coil is constructed by accommodating a primary coil 1, and a secondary coil 2 which is concentrically fitted around the coil 1 in a bottomed insulating case 3 having an opening in its bottom; closing the opening of the case 3 with one end of a bobbin 1' of the coil 1; charging an insulating resin into the case 3; fixing both coils 1 and 2 inside the case 3 with a cured insulating resin layer 7; inserting inner leg portions 9 of a pair of iron cores 8 and 8 for forming a closed magnetic circuit, which are integrally formed of the portions 9 penetrating into the bobbin 1' and outer leg portions 10 extending in parallel with the portions 9, while located outside the case 3, from their ends into a hollow portion of the bobbin 1' to thereby cause the portions 9 abut each other; and clamping a bonded magnet 12 having rubber-like elasticity between ends of the portions 10 outside the case 3, to thereby cause the ends of the portions 10 to be opposed to each other through the magnet 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold-type ignition coil for an internal combustion engine for supplying a high voltage for generating spark discharge to a spark plug of an automobile engine, for example.
In particular, the present invention relates to an ignition coil that requires miniaturization.

[0002]

2. Description of the Related Art A primary coil and a secondary coil concentrically fitted outside the primary coil are housed in an insulating case having a bottom and an opening at the bottom, and are housed at one end of a bobbin of the primary coil. The opening at the bottom of the insulating case is closed, an insulating resin is poured into the insulating case, the primary and secondary coils are fixed in the insulating case with a solidified insulating resin layer, and a bobbin of the primary coil is provided. A bobbin of a primary coil, wherein each of the inner legs is a primary coil of a pair of iron cores for a closed magnetic path integrally including an inner leg protruding into the inner leg and an outer leg parallel to the inner leg and located outside the insulating case; A mold for an internal combustion engine in which the ends of the outer legs are inserted into each hollow part of the hollow part of the inner part and butt against each other, and the ends of the outer legs are opposed to each other via a plate-shaped permanent magnet such as samarium-cobalt outside the insulating case. Type ignition coil is disclosed in Japanese Unexamined Patent Publication No. 9-30 of the present applicant.
It is known from U.S. Pat.

[0003]

The above-mentioned known ignition coil obtains a small but high spark energy due to the reverse excitation effect of the permanent magnet which is magnetized in the direction opposite to the excitation direction by energizing the primary coil. However, when assembling the ignition coil, the permanent magnet is often damaged when the permanent magnet is sandwiched between the ends of the outer legs of the pair of iron cores. It takes time and effort to sandwich the magnet between the ends of the outer legs so that the magnet is not damaged, resulting in poor productivity. For this reason, it has been proposed to attach a spacer to the magnet and sandwich it between the ends of the outer legs to prevent the permanent magnet from being damaged.However, in this case, the spacer is required, and the end of the outer leg is required. When the permanent magnet is sandwiched between the parts, there is a problem that it takes time and trouble to attach the spacer to the permanent magnet together.

[0004]

SUMMARY OF THE INVENTION The present invention has been developed to solve the above-mentioned problems, and has an inner leg projecting into a bobbin of a primary coil and an insulating case parallel to the inner leg. Of a pair of iron cores with the outer legs located outside,
A rubbery elastic bonded magnet is sandwiched between the ends of each outer leg, and the ends of the both legs are opposed to each other via a rubbery permanent magnet outside the insulating case.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the illustrated embodiment, 1 is 1
The secondary coil, 2 is a secondary coil concentrically fitted outside the primary coil, 3 is a bottomed insulating case made of synthetic resin or the like,
The bottom has an opening which is closed at one end of the bobbin 1 'of the primary coil, and a high-pressure cylinder portion 4 from which the high-voltage terminal is mounted projects downward from the bottom.

[0006] Both the primary and secondary coils are concentrically housed in the insulating case 3 and one end of the bobbin 1 'of the primary coil closes an opening at the bottom of the insulating case 3 so that the coils 1 and 2 are placed inside the case. And insert the high-voltage terminal 5 into the high-pressure cylinder 4 to close it, and connect the winding end of the lead wire of the secondary coil to the high-voltage terminal 5,
The lead wires at both ends of the primary coil and, if necessary, the winding start ends of the lead wires of the secondary coil are also connected to the primary connector 6 integrally formed at the other end of the primary bobbin. Then, an insulating resin such as a thermosetting epoxy resin is vacuum-injected into the insulating case 3, and the cured resin layer 7 is used to connect the primary and secondary coils, the high voltage terminal, and the primary connector to the insulating case. And fix it. The other end of the bobbin 1 ′ of the primary coil slightly projects upward from the upper surface of the insulating resin layer 7.

Reference numeral 8 denotes a pair of C-type or J-type closed magnetic cores formed by laminating silicon steel plates or the like, and each of the cores is inserted into a hollow portion of a bobbin of a primary coil from each end portion to form a hollow portion in the hollow portion. And the outer legs 10 and 10 located outside the insulating case are integrally provided. Outside the insulating case 3, when the inner legs 9, 9 of the pair of cores 8, 8 are inserted into the hollow portion of the primary bobbin from each end, the outer legs 1
The storage cylinder 11 into which the 0 and 10 enter from each end may be provided integrally in the vertical direction.

When each end of the inner legs 9, 9 of the pair of cores is inserted from each end into the hollow portion of the bobbin 1 'of the primary coil, rubber is attached to one end 10' of the outer legs 10, 10. The bonded magnet 12 having high quality is fixed by bonding or the like.

The rubbery bonded magnet is a permanent magnet powder that is made of a flexible binder such as NB.
R (acrylonitrile butadiene rubber) and CPE
(Chlorinated polyethylene), etc.
For use, the slice is sliced to have the same sectional area as the end of the outer leg 10 and a thickness of about 1 mm.

In this case, as shown in FIG. 1B, the length obtained by adding the thickness (t) of the bond magnet 12 to the total length (a + a) of both outer legs 10, 10 of the pair of iron cores is as follows: Both inner legs 9,
9 is slightly longer than the total length (b + b) of, for example, 0.1 mm, and when the ends of both inner legs abut each other, each end 10 ′, 10 ′ of both outer legs has a bond length of about 0.1 mm. It is preferable to bite into the magnet 12.

Thus, each end of the inner legs 9, 9 of the pair of iron cores is inserted into the hollow portion of the bobbin 1 'of the primary coil from each end and is abutted and bonded in the bobbin 1' or shown in the drawing. When the concave and convex engaging portions are engaged or fixed, the outer legs 1
The ends 10 'and 10' of the outer legs 10 'and 10' enter the housing cylinder from the respective ends, and are bonded to the bonded magnet 12 fixed to the end 10 'of one outer leg by bonding or the like. After the ends abut, each end 10 ', 10' bites into the bond magnet 12, so that the bond magnet 12 can be connected to both outer legs 10,
The ends 10 ′, 10 ′ of 10 face each other via the bond magnet 12.

The end face of each end 10 'of both outer legs is shown in FIG.
It may be perpendicular to the longitudinal direction of the leg as in (1) of (B), or 30 to 45 ° relative to the longitudinal direction of the leg as shown in (2) of FIG. May have a degree of inclination angle θ.

[0013]

As described above, since the bond magnet 12 has rubbery elasticity as described above, it does not break even if it is sandwiched between the ends 10 ', 10' of the outer legs 10, 10. Therefore,
The bond magnet can be sandwiched between the ends 10 ', 10' of the pair of outer cores located outside the insulating case of the pair of iron cores without breakage, thereby producing high productivity with small size and high spark energy. An ignition coil can be provided.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of one embodiment of an ignition coil according to the present invention, and FIG. 1B is an explanatory view of the relationship between a pair of iron cores and permanent magnets.

FIG. 2 is a perspective view of the ignition coil of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Primary coil 2 Secondary coil 3 Insulation case 4 High-pressure cylinder part of an insulation case 5 High-voltage terminal 6 Primary connector 7 Insulating resin layer 8 Iron core 9 Iron core inner leg 10 Iron core outer leg 11 Outer leg accommodation cylinder part 12 Rubber Quality bonded magnet

Claims (1)

[Claims] 1. A primary coil and a secondary coil concentrically fitted outside the primary coil are housed in an insulating case having a bottom and an opening at a bottom, and are housed at one end of a bobbin of the primary coil. The opening at the bottom of the insulating case is closed, an insulating resin is poured into the insulating case, the primary and secondary coils are fixed in the insulating case with a solidified insulating resin layer, and a bobbin of the primary coil is provided. A bobbin of a primary coil, wherein each of the inner legs is a primary coil of a pair of iron cores for a closed magnetic path integrally provided with an inner leg protruding into the inner leg and an outer leg parallel to the inner leg and located outside the insulating case; Insert from each end into the hollow part of the outer case and butt, sandwich the rubbery elastic bonded magnet between the ends of each outer leg outside the insulating case, and connect the ends of both outer legs via permanent magnets. A molded ignition coil characterized by being opposed to each other.