JPH0129782Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cap structure for improving the insulation between the high voltage take-out portion of the secondary coil of a closed magnetic circuit type ignition coil and the case.

Generally, a closed magnetic circuit type ignition coil is assembled by fitting a primary coil 1 into the inner periphery of a bobbin of a secondary coil 2 and passing an iron core 3 through the inner periphery of the bobbin of the primary coil, as shown in Figures 1 and 2. - The core assembly is placed horizontally in a metal case 4, an oil-impregnated elastic piece 5 such as felt is placed on the upper surface of the outer periphery of the secondary coil, and the core assembly is placed on the step 4' of the enlarged part provided at the top of the case. Patsukin 6
After laying the cap 7, the flange 7' which is integrally protruding from around the cap 7 made of electrically insulating material is received on the packing 6, the cap 7 is fitted into the case, and the upper edge of the enlarged part of the case 4 is inserted into the cap. The cap is bent to the top surface of the flange and caulked, thereby fixing the cap to the case and closing the top surface of the case, and pressing and fixing the coil-iron core assembly to the bottom of the case via the oil-impregnated elastic piece 5 on the bottom surface of the cap. Then, after filling the case with insulating oil 9 through a hole at the bottom of the cylindrical high voltage tower 8 that stands upright from the cap 7, a high voltage terminal 10 is attached to the hole and the hole is sealed, and the lower end of the high voltage terminal is closed. It is electrically connected to the winding end of the secondary coil via a high voltage lead-out portion 11 such as a spring.

The cap 7 has a downwardly protruding frame 12 on its lower surface into which the upper parts of the secondary coil and the primary coil are fitted, and this frame 12 prevents the coil-core assembly from moving in the axial direction. Projecting pieces 12', 12' projecting downward from the frame 12 prevent the coil-core assembly from moving in a direction perpendicular to the axial direction.

Now, since the lower surface of the interior of the conventional cap surrounded by the frame 12 is a horizontal flat surface, a space s is created between this lower surface and the outer peripheral upper surface of the secondary coil, and when the ambient temperature is high, the case Oil filled inside 9
fills the space s, but as the ambient temperature drops, the oil contracts, the oil level 9' drops, and there is no oil in the space s, so it is generated in the secondary coil and taken out from the high voltage terminal 10. There is a drawback that the high voltage leaks from the high voltage lead-out portion 11 through the space s to the case 4, and the high voltage cannot be effectively taken out to the high voltage terminal 10.

Therefore, the present invention solves the conventional problems by curving the lower surface of the cap, that is, the lower surface of the interior surrounded by the above-mentioned frame 12, in correspondence with the outer peripheral upper surface of the secondary coil.

FIG. 3 shows an embodiment of the present invention, in which the lower surface of the cap surrounded by the frame 12 is formed into a smooth curved surface 13 corresponding to the outer peripheral upper surface of the secondary coil. As a result, when the cap is fixed to the case, the entire surface of the curved surface 13 comes into contact with the outer circumferential upper surface of the secondary coil via the oil-impregnated elastic piece 5, and there is no difference between the lower surface of the cap and the outer circumferential upper surface of the secondary coil as in the conventional case. space s
does not occur. Therefore, even if the oil level 9' drops, the high voltage generated in the secondary coil can be prevented from leaking from the high voltage lead-out portion 11 to the case.

Curving the lower surface of the cap is not limited to forming a smooth curved surface 13 as in the above example, but it is also possible to form step-like thick walls 14, 14 on both sides of the lower surface as shown in FIGS. 4 and 5. As shown in Fig. 6, a large number of parallel fins 15 are integrally protruded downward from the flat underside, and the downward length of the fins is made shorter toward the center and longer toward the outside on both sides. ,
A line connecting the corners of the thick parts 14, 14, or the fin 15
The wire connecting the lower ends of... may be placed along the upper surface of the outer periphery of the secondary coil, which effectively prevents leakage by increasing the insulation distance or edge distance when high voltage leaks into the case. can do.

Then, the oil-impregnated elastic piece 5 is sandwiched between the curved lower surface of the cap and the outer circumferential upper surface of the secondary coil, and both ends 5', 5' of the oil-impregnated elastic piece 5 are placed below the oil level when the ambient temperature drops. When left immersed in the oil-impregnated elastic piece, the oil-impregnated elastic piece always absorbs oil, and the oil-impregnated piece effectively prevents leakage to the high-voltage case.

Thus, according to the present invention, it is possible to stabilize the performance and improve the durability of the closed magnetic circuit type ignition coil.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional front view of a conventional closed magnetic circuit type ignition coil, FIG.
FIG. 5 is a vertical perspective view of the same cap as above, and FIG. 6 is a vertical side view of another embodiment. In the figure, 1 is a primary coil, and 2 is a secondary coil. , 3 is the iron core, 4 is the case, 5 is the oil-impregnated elastic piece, 7 is the cap, 7' is the collar, 9 is oil,
Reference numeral 11 indicates a high voltage lead-out portion, 13 indicates a curved surface on the lower surface of the cap, 14 indicates a stepped thick wall portion that curves the lower surface of the cap, and 15 indicates a fin.

Claims (1)

[Claims for Utility Model Registration] A coil-core assembly is constructed by penetrating an iron core through the inner periphery of a primary coil with a secondary coil fitted to its outer periphery. Next, an oil-impregnated elastic piece such as felt is placed on the top surface of the outer periphery of the coil, and a cap made of electrically insulating material that closes the top surface of the case is placed on top of the step of the enlarged section that has a step provided at the top around the case. The cap is fixed to the case by placing the integrally projecting flange and bending and caulking the upper edge of the case onto the flange of the cap, and attaching the coil-iron core assembly to the case via an oil-impregnated elastic piece on the underside of the cap. Press it against the bottom of the
In addition, in a closed magnetic circuit type ignition coil whose case is filled with oil, the lower surface of the cap is curved to correspond to the outer circumferential upper surface of the secondary coil in order to prevent high voltage leakage. coil.