JP2011077485A - Ignition coil for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition coil for an internal combustion engine capable of electrically connecting a terminal pin and a high-pressure terminal, without fail. <P>SOLUTION: The ignition coil for an internal combustion engine includes a primary coil and a secondary coil wound around a coil bobbin, an iron core magnetically coupling these two coils, and an insulating case for accommodating them therein. The primary coil, the secondary coil, the iron core, and the like, are fixed and held by an insulated synthetic resin with which the insulating case is filled. A curved portion is formed in a tip of a terminal pin connected to the secondary coil; a recessed groove is formed at a side of a high pressure terminal electrically connected with the terminal pin; and the curved portion formed in the tip of the terminal pin is fitted and conducted into the recessed groove formed on the side of the high-pressure terminal, thereby electrically connecting the terminal pin and the high-pressure terminal, without fail. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a molded type ignition coil for an internal combustion engine that supplies a high-voltage current to generate a spark discharge in an ignition plug of an engine such as an automobile.

  FIG. 4 is a longitudinal sectional view showing the relationship between a high voltage terminal and a terminal pin in a conventional ignition coil for an internal combustion engine. In FIG. 4, an ignition coil 1 for an internal combustion engine is attached to an iron core / coil assembly 2, a synthetic resin insulating case 3 that accommodates the iron core / coil assembly 2, and a high-pressure tower portion of the insulating case 3. The high-voltage terminal 4 and the thermosetting resin 5 having an insulating property for fixing each component in the insulating case 3 while being insulated.

  The above-described iron core / coil assembly 2 includes an iron core 6 that forms a closed magnetic circuit, a primary coil bobbin 7 through which the iron core 6 is inserted, a primary coil 8 wound around the primary coil bobbin 7, and a primary coil 8. A secondary coil bobbin 9 formed concentrically with the primary coil bobbin 7, a secondary coil 10 wound around the secondary coil bobbin 9, and a terminal pin 11 to which the winding end of the secondary coil 10 is connected Has been. The terminal pin 11 to which the winding end of the secondary coil 10 is connected is positioned so as to correspond to the high-voltage terminal 4 that has been cut or pressed into a cylindrical shape or a conical shape with aluminum, brass, or the like. The high voltage terminal 4 is disposed so as to be in pressure contact.

  The lower end of the insulating case 3 is a high-voltage tower 12 that houses the high-voltage terminal 4, and is fitted to a protector 13. Further, the lower end of the protector 13 is fitted to the spark plug 14, and a spring 15 housed in the protector 13 electrically connects the high voltage terminal 4 and the spark plug 14.

  When the primary coil 8 of the internal combustion engine ignition coil 1 configured as described above is cut off after a predetermined current is passed through the primary terminal 16 and both primary terminal pins, the high voltage generated in the secondary coil 10 Is supplied from the high-voltage terminal 4 and the spring 15 to the spark plug 14 via the terminal pin 11.

JP 2009-27064 A

  However, in the conventional ignition coil for an internal combustion engine having such a configuration, the position of contact with the high voltage terminal differs depending on the size of the high voltage side terminal of the secondary coil, and the contact area varies. For this reason, even if electrical continuity is obtained at the initial stage of manufacture, when the internal temperature rises during operation of the ignition coil, the linear expansion coefficients of the wire, the high voltage terminal, and the thermosetting resin are different, and the terminal pin and the high voltage terminal In the connection portion, the contact held by the elasticity of the terminal pin itself is interrupted, and a conduction failure may occur.

  The present invention has been proposed in view of the above. A curved portion is formed at the tip of the terminal pin, a concave groove is formed on the high-voltage terminal side electrically connected to the terminal pin, and the curved portion is formed into a concave groove. It is an object of the present invention to provide an ignition coil for an internal combustion engine that can ensure electrical connection by fitting.

  In order to achieve the above object, an ignition coil for an internal combustion engine according to the present invention includes a primary coil and a secondary coil wound around a coil bobbin, an iron core that magnetically couples these two coils, and an insulating case that houses them. An ignition coil for an internal combustion engine that fixes and holds a primary coil, a secondary coil, an iron core, etc. with an insulating synthetic resin filled in the insulating case, and a terminal pin connected to the secondary coil A concave portion is formed on the high-voltage terminal side, and a concave groove is formed on the high-voltage terminal side that is electrically connected to the terminal pin. It is characterized in that it is fitted inside and made conductive.

  In the present invention, the curved portion of the terminal pin is formed in a U shape with a convex tip.

  In the present invention, the curved portion of the terminal pin is formed by being refracted a plurality of times.

  In the present invention, the terminal pin holding portion is disposed so as to be in contact with substantially the center of the terminal pin.

  Since this invention consists of an above-described structure, there can exist an effect which is demonstrated below.

  In the present invention, there are provided a primary coil and a secondary coil wound around a coil bobbin, an iron core that magnetically couples these two coils, and an insulating case that accommodates them, and the insulating case filled in the insulating case An ignition coil for an internal combustion engine in which a primary coil, a secondary coil, an iron core, etc. are fixedly held by a synthetic resin, and a curved portion is formed at a tip of a terminal pin connected to the secondary coil, and the terminal pin and the electric coil A concave groove is formed on the side of the high-voltage terminal to be connected to the end, and the curved portion formed at the end of the terminal pin is fitted into the concave groove formed on the side of the high-voltage terminal so that the terminal pin is made conductive. The electrical connection can be ensured by reliably contacting the high voltage terminal. Therefore, it is possible to prevent conduction failure due to thermal stress generated during operation of the ignition coil.

  Further, in the present invention, the bent portion of the terminal pin is formed in a U-shape with a convex tip, so that the fitting operation into the recessed groove formed on the high-voltage terminal side is easy.

  Further, in the present invention, the bent portion of the terminal pin is formed by being refracted a plurality of times, so that stable conduction can be obtained without causing variations in the contact area with the high voltage terminal. Further, stable electrical continuity can be ensured without losing contact between the terminal pin and the high-voltage terminal, regardless of temperature stress caused by the difference in linear expansion coefficient among the wire, high-voltage terminal, and insulating material.

FIG. 1 is a longitudinal sectional view showing the relationship between a high voltage terminal and a terminal pin in an ignition coil for an internal combustion engine according to the present invention. FIG. 2 is an enlarged perspective view showing the relationship between the high-voltage terminal and the terminal pin. FIG. 3 is an enlarged perspective view showing another embodiment of the terminal pin. FIG. 4 is a longitudinal sectional view showing the relationship between a high voltage terminal and a terminal pin in a conventional ignition coil for an internal combustion engine.

  In the ignition coil for an internal combustion engine, a curved portion is formed at the tip of the terminal pin, and a concave groove into which the curved portion can be inserted is formed on the high-voltage terminal side electrically connected to the terminal pin. By fitting in the groove, the terminal pin and the high voltage terminal can be brought into reliable contact with each other, and the reliability of electrical conduction can be improved.

  Hereinafter, the present invention will be described in detail with reference to the drawings illustrating an embodiment. FIG. 1 is a longitudinal sectional view showing a relationship between a high voltage terminal and a terminal pin in an ignition coil for an internal combustion engine according to the present invention. Here, the ignition coil 20 for the internal combustion engine includes a primary coil bobbin 21, a primary coil 23 and a secondary coil 24 wound around a secondary coil bobbin 22, an iron core 25 that magnetically couples these two coils, and these. A primary coil 23, a secondary coil 24, an iron core 25, and the like are fixedly held by an insulating synthetic resin 27 filled in the insulating case 26. A curved portion 28a is formed at the tip of the terminal pin 28 connected to the terminal pin 28, and a concave groove 30 is formed on the side of the high voltage terminal 29 electrically connected to the terminal pin 28, and is formed at the tip of the terminal pin 28. The bent portion 28a is fitted into a concave groove 30 formed on the high-voltage terminal side to be conducted.

The secondary coil bobbin 22 has a plurality of flange portions 22a for dividing the secondary coil. The terminal pin 28 attached to one end of the secondary coil bobbin 22 extends in the direction of the high voltage terminal 29 disposed below, and has a curved portion 28a at the tip. As shown in FIG. 2, the bending portion 28 a of the terminal pin 28 is folded back in a U-shape and has a convex end.
In addition, the curved portion 28a is formed to have a diameter W that can be substantially fitted into the concave grooves 30 that are arranged to face each other. The folding height H is substantially equal to the depth of the concave groove 30. In addition, the concave groove 30 is formed in a cylindrical shape, for example, but may have another shape as long as the curved portion 28a can be fitted.

  FIG. 3 is an enlarged perspective view showing another embodiment of the terminal pin, and the curved portion 28b of the terminal pin 28 has a convex shape that is refracted a plurality of times. Also in this case, the curved portion 28a is formed to have a diameter W that can be fitted into the concave groove 30 of the high-voltage terminal 29 that is disposed to face the curved portion 28a. Further, the folding height H is also formed approximately equal to the depth of the concave groove 30.

  A procedure for assembling the ignition coil 20 for the internal combustion engine configured as described above will be described. First, after the high voltage terminal 29 is disposed in the high voltage tower section 12 of the insulating case 26, an assembly including the primary coil 23, the secondary coil 24, the iron core 25 and the like is accommodated in the insulating case 26.

  At this time, the curved portion 28 a of the terminal pin 28 extending to the lower end side of the assembly is fitted into a concave groove 30 formed at the upper end of the high-voltage terminal 29. Thereafter, an insulating synthetic resin 27 is injected to fix each component while being insulated.

  In the ignition coil 20 for an internal combustion engine manufactured in this way, the terminal pin 28 and the high voltage terminal 29 ensure electrical contact because the curved portion 28a of the terminal pin 28 is press-fitted into the concave groove 30. be able to. Even when a force is applied to the terminal pin 28 due to thermal stress or the like, the curved portion 28a is repelled by the elastic force of the wire itself, the contact between the terminal pin 28 and the high-voltage terminal 29 is released, and conduction is interrupted. There is no fear of being done.

  In addition, as shown in FIG. 3, when the tip of the bent portion 28 b of the terminal pin 28 refracted a plurality of times has a convex shape, the fitting operation into the concave groove 30 can be facilitated. it can. Furthermore, the terminal pin 28 can be configured not to easily come out of the recessed groove 30.

  As described above, according to the configuration of the present invention, even when there is a variation in dimensions on the high voltage side terminal of the secondary coil, it can be reliably press-fitted into the concave groove of the high voltage terminal. The reliability can be improved without fear of the contact being separated due to the temperature stress.

DESCRIPTION OF SYMBOLS 1 Ignition coil for internal combustion engines 2 Iron core and coil assembly 3 Insulation case 4 High voltage terminal 5 Thermosetting resin 6 Iron core 7 Primary coil bobbin 8 Primary coil 9 Secondary coil bobbin 10 Secondary coil 11 Terminal pin 12 High voltage tower part 13 Protector 14 Ignition Plug 15 Spring 16 Primary terminal 20 Ignition coil 21 for internal combustion engine Primary coil bobbin 22 Secondary coil bobbin 23 Primary coil 24 Secondary coil 25 Iron core 26 Insulating case 27 Insulating synthetic resin 28 Terminal pin 28a Bending portion 29 High voltage terminal 30 Concave groove

Claims (3)

A primary coil and a secondary coil wound around a coil bobbin, an iron core that magnetically couples these two coils, and an insulating case that accommodates them, and an insulating synthetic resin filled in the insulating case An ignition coil for an internal combustion engine that fixes and holds a primary coil, a secondary coil, an iron core, etc.
While forming a curved portion at the tip of the terminal pin connected to the secondary coil,
Forming a concave groove on the high-voltage terminal side electrically connected to the terminal pin;
An ignition coil for an internal combustion engine, wherein a bending portion formed at a tip of the terminal pin is fitted into a concave groove formed on a high-voltage terminal side to be conducted.   2. The ignition coil for an internal combustion engine according to claim 1, wherein the curved portion of the terminal pin is formed in a U shape having a convex tip.   The ignition coil for an internal combustion engine according to claim 1 or 2, wherein the curved portion of the terminal pin is formed by being refracted a plurality of times.

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