JP3588830B2 - Ignition coil for internal combustion engine - Google Patents

Description

[0001]
[Industrial applications]
The present invention particularly relates to an ignition coil (hereinafter simply referred to as an ignition coil) for an internal combustion engine that outserts a high voltage terminal to a coil case.
[0002]
[Prior art]
A high-voltage terminal a connected to a secondary coil is mounted in a terminal mounting hole c provided in a coil case b, and an ignition coil for injecting and hardening a potting resin d in the coil case b is a high-voltage terminal as shown in FIG. The O-ring e fitted on the outer periphery of a seals the potting resin d to be injected from leaking from the terminal mounting hole c. However, in the ignition coil having the above configuration, when high voltage generated in the secondary coil ignites when it is ignited by the rotor of the distributor or the electrode of the spark plug, the high voltage terminal functions as an antenna for the ignition noise and causes other functions. However, there is a problem that radio noise is exerted on the electrical components.
[0003]
Japanese Patent Application Laid-Open No. 2-207512 discloses a configuration in which radio noise can be prevented by piercing a conductive needle-like body on the secondary coil side into a rubber soft conductor provided on the high voltage terminal side. ing. However, in this configuration, if ignition noise is generated when a spark is generated by the rotor of the distributor or the electrode of the spark plug, the high-voltage terminal functions as an antenna for the ignition noise and exerts electrical noise on other electrical components.
[0004]
[Problems to be solved by the invention]
The present invention has been made in order to solve the above problems, and an object of the present invention is to provide an ignition coil that can prevent the potting resin to be injected from leaking from a terminal mounting hole and can enhance an effect of preventing radio noise. And
[0005]
[Means for Solving the Problems]
In order to achieve the above object, an ignition coil according to the present invention has a cup-like shape, a projection to which a high-voltage end side of a secondary coil is connected is formed on a top portion, and a terminal mounted on a coil case. A high-pressure terminal attached to the hole and a hole through which the protrusion formed at the top of the high-voltage terminal is formed, and the high-voltage terminal is covered so as to pass the protrusion of the high-voltage terminal through the hole. And a cap made of a conductive elastic material interposed between the terminal mounting hole and the high-voltage terminal, wherein potting resin is injected into the coil case and cured.
[0006]
According to a second aspect of the present invention, there is provided an ignition coil according to the first aspect, wherein the outer peripheral surface of the high-voltage terminal and the inner peripheral surface of the cap are fitted in a male-female relationship. A projection and a recess are provided.
[0007]
[Action and effect of the invention]
According to the ignition coil according to the first aspect of the present invention, the cap formed of the conductive elastic material is placed in a cup-like shape, and is mounted on the high-voltage terminal having the projection to which the secondary coil is connected on the top, and the terminal is mounted. Attach to the hole. Therefore, a conductive elastic material is interposed between the terminal mounting hole and the high-voltage terminal, so that the sealing property that prevents the injected potting resin from leaking is enhanced, and the cap that covers the high-voltage terminal reflects and absorbs ignition noise. And the effect of reducing the radio noise applied to the outside can be reduced, thereby improving the effect of preventing the ignition coil from generating radio noise.
[0008]
Further, according to the ignition coil of the present invention, when the high-voltage terminal is covered with the cap, the projection and the recess having a male and female relationship are fitted. Therefore, the sealing property between the terminal mounting hole and the high-voltage terminal is further improved, and the adhesion between the high-voltage terminal and the cap is improved. There is an effect that can be attached to.
[0009]
【Example】
Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows an ignition coil 1 according to the present invention. A cylindrical high-voltage terminal mounting portion 3 is integrally formed by injection molding on a coil case 2 made of an insulating resin having one end opened. A high-voltage terminal mounting hole 4 is formed in the high-voltage terminal mounting section 3 in a penetrating manner. The high-pressure terminal mounting hole 4 has a reduced diameter step 5 provided substantially in the middle, and is formed in a shape in which the hole diameter is gradually increased from the reduced diameter step 5 toward the distal end. In the coil case 2, a winding portion 10 formed by fitting a coil bobbin 9 wound with a secondary coil 8 around the outer periphery of a coil bobbin 7 wound with a primary coil 6 is inserted.
[0010]
Both ends of the primary coil 6 are connected to two terminals 12 and 13 provided on the connector 11 by soldering or the like. The low-voltage side of both ends of the secondary coil 8 is soldered to the terminal 12 or 13 of the connector 11 which is connected to the battery. The high pressure side is connected to the high voltage terminal 14. As shown in FIG. 3A, the high-voltage terminal 14 made of metal such as aluminum or brass has a cup-like shape provided with a concave portion 14a into which a male terminal of a high tension cord (not shown) is inserted. Are formed with two parallel fitting ring grooves 15. At the top of the high voltage terminal 14, a winding protrusion 16 for winding and soldering the high voltage side end of the secondary coil 8 is formed.
[0011]
The high-voltage terminal 14 is covered with a cap 17 made of conductive rubber as shown in FIG. The cap 17 is formed in a shape substantially corresponding to the appearance of the high-voltage terminal 14, and is fitted into a hole 18 through which the winding projection 16 of the high-voltage terminal 14 passes and a fitting ring groove 15 on the inner periphery. A ridge 19 having a substantially semicircular cross section is formed, and a ridge 32 having a substantially semicircular cross section is formed on the outer periphery. The high-voltage terminal 14 covered with the cap 17 is wound around the high-voltage end of the secondary coil 8, soldered and connected, and then pushed down to the reduced-diameter step portion 5 of the high-voltage terminal mounting hole 4 for mounting. At this time, the protrusion 32 on the outer periphery of the cap 17 is pressed against the inner periphery of the terminal mounting hole 4. Thereafter, a thermosetting potting resin 20 such as an epoxy resin is injected and filled into the coil case 2 and is cured by heating to integrate the ignition coil 1. Then, two U-shaped cores 21 are press-fitted from both sides of the center hole 7a of the coil bobbin 7 of the primary coil 6 and fixed.
[0012]
In the ignition coil 1 having the above-described structure, the cap 17 is sandwiched between the terminal mounting hole 4 and the high-voltage terminal 14, and the sealing property is improved by fitting the ridge 32 and the terminal mounting hole 4. Since the circumferential ridge 19 is fitted in the fitting ring groove 15 of the high-voltage terminal 14, the adherence between the high-voltage terminal 14 and the cap 17 is improved, so that the cap 17 It can be easily mounted without turning up from the edge of the. Further, since the protrusions 32 on the outer periphery of the cap 17 are pressed against the inner periphery of the terminal mounting hole 4, the potting resin 20 to be injected does not leak from between the terminal mounting hole 4 and the high-voltage terminal 14.
[0013]
The cap 17 is made of conductive rubber. The conductive rubber is made of carbon black, metal powder, or the like, and can have a desired resistance depending on the compounding, and reflects and absorbs ignition noise. The shield effect can be exhibited. The cap 17 may be made of various synthetic rubbers such as EPDM and NBR, natural rubber, polyethylene, polypropylene, ABS resin, and other soft resins mixed with a predetermined amount of carbon black, metal powder, or the like. Those having properties can be used. The cap 17 may be assembled to the high-pressure terminal 14 after molding, or may be integrally formed with the high-pressure terminal 14.
[0014]
The number of fitting ring grooves 15 provided on the outer periphery of the high-voltage terminal 14 is not limited to two as in the above embodiment, but may be three or more. Alternatively, a spiral fitting groove 25 may be used as shown in FIG. In this case, on the inner periphery of the cap 17, as shown in FIG. 4 (b), a spiral ridge 29 having a relationship between the fitting groove 25 and the male and female is formed. Thus, the cap 17 can be easily attached to the high-voltage terminal 14 by screwing.
In addition, it is not always necessary to provide the protrusions 32 on the outer periphery of the cap 17. In this case, the potting resin 20 to be injected is sealed by the outer periphery of the cap 17 and the high-pressure terminal mounting hole 4.
[0015]
Further, as shown in FIG. 5, an inward flange 30 that covers the edge of the concave portion 14 a of the high-voltage terminal 14 and abuts on the reduced-diameter step portion 5 of the terminal mounting hole 4 is formed on the edge of the cap 17. In addition, when mounted in the terminal mounting hole 4, the cap 17 may be prevented from turning up from the end.
The high voltage terminal 14 and the cap 17 can be applied to a simultaneous ignition type ignition coil 31 having two high voltage terminals as shown in FIG.
[Brief description of the drawings]
FIG. 1 is a perspective view of an ignition coil.
FIG. 2 is a sectional view of an ignition coil.
FIG. 3 is a sectional view of a high-pressure terminal and a cap.
FIG. 4 is a sectional view of another high-pressure terminal and a cap.
FIG. 5 is a partially cutaway side view showing a modification of the cap.
FIG. 6 is a perspective view of a simultaneous ignition type ignition coil.
FIG. 7 is a sectional view of a main part for explaining a conventional example.
[Explanation of symbols]
1, 31 ignition coil 2 coil case 4 terminal mounting hole 8 secondary coil 14 high voltage terminal 15 fitting ring groove (recess)
17 cap 19 ridge (protrusion)
20 Potting resin 25 Spiral fitting groove (recess)
29 Spiral ridges (projections)

Claims (2)

A high-voltage terminal mounted in a terminal mounting hole provided in the coil case, the protrusion having a cup-like shape, having a top formed with a high-voltage end of the secondary coil connected thereto;
A hole is formed through the protrusion formed at the top of the high-voltage terminal. The hole is covered with the high-voltage terminal so that the protrusion of the high-voltage terminal passes through the hole. A cap made of a conductive elastic material interposed between the terminal and
An ignition coil for an internal combustion engine, wherein potting resin is injected into the coil case and cured. Wherein the outer peripheral surface of the high-tension terminal and the inner peripheral surface of the cap, the ignition coil for an internal combustion engine according to claim 1, characterized by providing a protrusion and a recess to be fitted with male and female relationships.

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