JP2001193620A - Electrically connecting device for ignition coil and ignition plug for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the end face of a high voltage terminal from being worn even if the high voltage terminal of a soft metal such as aluminum alloy, brass or the like is used, and to also prevent very fine powder of a metal such as aluminum alloy, brass or the like from being produced, when connecting the high voltage terminal in the high voltage cylinder part of an ignition coil to the coil spring of a plug socket. SOLUTION: In this electrically connecting device for an ignition coil and an ignition plug for an internal combustion engine comprising the columnar high voltage terminal 5 of the ignition coil and the coil spring 28 of a plug socket 20 to supply the high voltage of the ignition coil to the top terminal of the ignition plug through the high voltage terminal, with its one end breaking in a high voltage cylinder part 4 and abutting on the end face of the high voltage terminal and with the other end brought into contact with the top terminal 13 of the ignition plug 12 attached to the internal combustion engine, a circular recessed part 30 is provided on the end face of the high voltage terminal of the ignition coil having one end part of the coil spring of the plug socket abutting on it, in order to make the terminal end 29 of the coil spring 28 break into the circular recessed part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for electrically connecting an ignition coil of an internal combustion engine and an ignition plug via a coil spring of a plug socket to supply a high voltage generated in the ignition coil to the ignition plug. The present invention relates to an electrical connection device between an ignition coil and an ignition plug of an internal combustion engine, which generates a spark discharge for igniting a fuel mixture of the internal combustion engine.

[0002]

2. Description of the Related Art Both primary and secondary coils of an ignition coil are housed, and an insulating resin layer cast and hardened inside is integrally and outwardly protruded from a wall surface of an insulating case in which the both coils are fixed. A cylindrical high-voltage terminal of the ignition coil, which is provided on the inner periphery of the hollow high-pressure cylinder and is connected to the winding end side of the secondary coil, and one end of which protrudes into the high-pressure cylinder and an end face of the high-voltage terminal; The high-voltage induced in the secondary coil of the ignition coil is applied through the high-voltage terminal to the head electrode of the ignition plug in elastic contact with the other end and the top terminal of the ignition plug attached to the internal combustion engine. 2. Description of the Related Art A device for electrically connecting an ignition coil and an ignition plug of an internal combustion engine, which comprises a plug socket having a coil spring to be supplied to a vehicle, is conventionally known.

[0003]

One end of the coil spring of the plug socket, when the plug socket is mounted over the high-pressure cylinder, ensures electrical continuity without being separated even by vibration of a vehicle equipped with an internal combustion engine. Therefore, it is in contact with the end face of the high voltage terminal while being elastically pressed by its own elasticity. By the way, high-voltage terminals are processed with headers from aluminum alloy, brass, etc. without cutting in order to efficiently and inexpensively manufacture, whereas coil springs of plug sockets are made of hard spring steel, considering workability and economy. A series of long base metal coils are manufactured by cutting with a cutter to the required length, and the cutting terminal by the cutter is not finished,
Since it is sharpened as it is cut off, one end that elastically contacts the high-voltage terminal of the ignition coil cuts the end face of the aluminum alloy, brass, etc. high-voltage terminal with a sharp terminal due to vibration of the vehicle, etc. The end faces of the terminals are worn and shaved, resulting in fine metal powder of aluminum alloy or brass. If this metal powder adheres to the resin of the high-pressure joint and non-dielectric metal powder (fine) adheres to a part of the high-dielectric resin pipe, the electric field concentrates on the low-dielectric part, and The insulation may be destroyed. Further, the metal powder may corrode in the spring, and may change the spring load of the spring. Furthermore, since a high voltage is applied to the spring, corona is generated, and ozone is generated by the corona, which causes various problems such as accelerated corrosion (oxidation) of the spring.

[0004]

SUMMARY OF THE INVENTION The present invention has been developed to solve the above-mentioned problem. A concave portion is provided in an end face of a high voltage terminal with which one end of a coil spring of a plug socket comes into contact, and the sharpness of the coil spring is improved. A terminal is inserted into the circular recess. In this case, the diameter of the inner circumference of the concentric circular recess on the end face of the high-voltage terminal is made slightly smaller than the outer diameter of the one end face of the coil spring, and the helical part of one end of the coil spring is applied to the annular part of the end face. It is preferable to make contact.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the illustrated embodiment, 10 is an ignition coil, 1 is a primary coil, 2 is a secondary coil concentrically fitted with the primary coil, and 3 is formed of synthetic resin or the like. 5 shows an insulating case with a bottom, the case having an opening at the bottom closed by one end of a bobbin of a primary coil. A high-pressure cylinder 4 protrudes from one side wall of the insulating case, and a high-voltage terminal 5 is mounted in the cylinder. A primary terminal seat 6 is provided on the other side of the side wall, and a primary terminal 7 is mounted here. The primary coil and the secondary coil, which are fitted concentrically, stand on the bottom in the insulating case, close the bottom opening at one end of the bobbin of the inner primary coil, and close the winding of the secondary coil. The end of the winding was connected to the high voltage terminal, and the winding of the primary coil was connected to the primary terminal 7, respectively, and the insulating case was filled with a thermosetting insulating resin, for example, an epoxy resin by vacuum casting and solidified. The insulating resin layer 8 fixes both the primary and secondary coils in the insulating case, the high-voltage terminal 5 in the high-pressure cylinder 4, and insulates the high voltage generated in the secondary coil. Then, the inner legs of a pair of iron cores 9 constituting a closed magnetic circuit such as a U-shape or a J-shape are inserted into the inner periphery of the bobbin of the primary coil from each end and fixed in a contact state by bonding or the like. The outer legs 9a, 9a of the two iron cores are directly butted outside the insulating case or butted via permanent magnets and fixed by bonding, welding, or the like. Thus, the illustrated ignition coil 10 is assembled.

In a cylinder head 11 of an internal combustion engine, a plug hole 1 having a spark plug 12 attached to the bottom for each cylinder is provided.
4 are provided. In the illustrated ignition coil 10, the ends 9 ′, 9 ′ of the pair of iron cores 9, 9 protrude out of the insulating case, and are used to fix the ignition coil directly above the plug hole. On the cylinder head, support stands 15, 15 are provided upright on the left and right sides of the upper end opening of the plug hole. Accordingly, the high-pressure cylinder of the ignition coil is directed downward and shallowly projects into the center of the upper end of the plug hole, and the respective ends 9 ', 9' of the iron core are placed on the supports 15, 15, and from each end, the support The ignition coil 10 can be fixed immediately above the plug hole by screwing the screws 16, 16 from above and tightening them on the ends of the iron core. Each end 9 'of the iron core is a connecting portion between the outer leg and the inner leg of the iron core.

Reference numeral 20 denotes a high voltage generated at the high voltage terminal 5 via the secondary coil when the current flowing through the primary coil of the ignition coil is cut off, to the top terminal 13 of the ignition plug 12 attached to the bottom of the plug hole. A hollow cylindrical portion 23 for elastically protruding into the upper inner periphery of the plug hole 14 and elastically holding the high-pressure cylindrical portion 4 of the ignition coil on the inner periphery, and extending around the hollow cylindrical portion. An upper socket 22 integrally provided with a seal flange 25 for elastically contacting the peripheral edge of the cylinder head around the upper end opening of the plug hole and sealing the upper end opening of the plug hole, and is attached to the bottom of the plug hole. An insulating sheathing material comprising a lower socket 26 elastically covering an upper portion having a top terminal 13 of a spark plug, and a relay tube 27 connecting the upper socket 22 and the lower socket 26. 1, the supported vertically during exterior material, a high voltage terminal 5 of the ignition coil, spring steel coil spring 2 for electrically connecting the top terminal 13 of the spark plug
And 8.

The upper socket 22 and the lower socket 26 are formed of synthetic rubber or synthetic resin having high elasticity, and the relay cylinder 27 is formed of ordinary synthetic resin. Then, the upper and lower ends of the relay tube are fitted into the inner periphery of the upper socket and the lower socket, then inserted into an annular groove provided concentrically outside the inner periphery, and fixed by bonding or the like, and the plug socket is fixed. Assemble. When the plug hole is shallow, the relay cylinder may be omitted, and the upper socket and the lower socket may be integrally molded to form an insulating exterior material. A high-voltage diode (not shown) is provided in the relay cylinder. A coil spring 28 is provided between the high-pressure diode and the top terminal 13 of the spark plug between the high-voltage diode and the high-voltage terminal 5. It may be composed of a compressed lower spring.

Therefore, the upper socket 22 of the plug socket 20 is fitted to the high-pressure cylinder of the ignition coil and the coil spring 28
The upper end of the plug socket is elastically abutted against the end face 5 'of the high voltage terminal 5, and the plug socket is attached to the ignition coil. The lower socket 26 of the plug socket is inserted into the plug hole from above, and the lower socket is elastically attached to the upper part of the ignition plug. When the lower end of the coil spring 28 is brought into contact with the top terminal 13 of the ignition plug, the hollow cylindrical portion 23 of the upper socket is pushed into the inner periphery of the upper end of the plug hole, and the sealing flange 25 is moved around the upper end opening of the plug hole. The upper end opening of the plug hole is sealed by contact. At this time, the air in the plug hole is compressed and the internal pressure increases. In addition, the operation of the internal combustion engine thermally expands the air in the plug hole and increases the internal pressure. When the internal pressure increases in this way, the air in the plug hole is exhausted from the seal flange 25 to the outside, though not shown.
Then, place the ignition coil 10 on the supports 15
Fix at 6.

Conventionally, as described above, the end face 5 'of the high-voltage terminal 5 of the ignition coil machined from an aluminum alloy, brass or the like with a header is connected to one end of the plug socket by a cutter of a spring steel coil spring made of spring steel. Sharp terminal 29
Are elastically in contact with each other (see FIG. 2), so that the sharp terminal 29 moves on the end face 5 'of the high-voltage terminal made of a soft metal due to the vibration of the vehicle or the like, and cuts and scratches the end face 5'. The insulating property is impaired by the metal powder generated in the step.

For this reason, in the present invention, a concentric circular recess 30 is provided in the end face 5 'of the high voltage terminal 5, and when one end of the coil spring 28 of the plug socket comes into contact with the end face 5', the sharpness is obtained. The terminal 29 is inserted into the circular recess 30 so as to be accommodated therein, thereby preventing the end face 5 'of the high voltage terminal from being damaged by the sharp terminal of the coil spring.

The diameter of the inner periphery of the circular recess 30 is slightly smaller than the outer diameter of one end of the coil spring 28, and the spiral portion 32 of one end of the coil spring comes into contact with the annular portion 31 of the outer periphery of the circular recess on the end surface. To do. To this end, the sharp end 29 of the coil spring is bent inward to ensure that it enters the circular recess 30 (see FIG. 1B), and the bottom of the circular recess 30 is not cut by the sharp end 29 of the coil spring. Deepen the circular recess so that sharp ends do not reach the circular recess.

[0013]

As is apparent from the above, according to the present invention, the end face of the high-voltage terminal made of a soft metal such as aluminum alloy or brass of the ignition coil is provided with the sharp end of one end of the spring steel coil spring of the plug socket. Terminal 29 does not abut. Therefore, there is no room for insulation failure due to the end face of the high voltage terminal being cut by the sharp end 29 of the coil spring.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view showing an embodiment of an electrical connection device using an ignition coil and a plug socket according to the present invention, in which an essential part is enlarged, and FIG. FIG.

FIG. 2 is an explanatory diagram showing a problematic part of a conventional electrical connection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Primary coil 2 Secondary coil 3 Insulating case 4 High voltage cylinder part 5 High voltage terminal 8 Insulating resin layer 9 Iron core 10 Ignition coil 12 Ignition plug 13 Top terminal of ignition plug 20 Plug socket 28 Coil spring of plug socket 29 Sharp terminal of coil spring Reference Signs List 30 Circular concave part on end face of high voltage terminal 31 Circular part on outer periphery of circular concave part 32 Spiral part of coil spring

Claims (2)

[Claims] 1. An insulating resin layer containing both primary and secondary coils of an ignition coil, which is cast and cured therein, and which is integrally and outwardly protruded from a wall surface of an insulating case in which the both coils are fixed. A cylindrical high-voltage terminal of the ignition coil, which is provided on the inner periphery of the hollow high-pressure cylinder and is connected to the winding end side of the secondary coil, and one end of which protrudes into the high-pressure cylinder and an end face of the high-voltage terminal; The high voltage induced in the secondary coil of the ignition coil is applied to the top terminal of the ignition plug through the high voltage terminal and the high voltage induced in the secondary coil of the ignition coil. In an electrical connection device for an ignition coil and an ignition plug of an internal combustion engine comprising a coil spring of a plug socket to be supplied, a recess is provided on an end face of a high voltage terminal of the ignition coil with which one end of the coil spring of the plug socket comes into contact. An electrical connection device for connecting an ignition coil and an ignition plug of an internal combustion engine, wherein the terminal is inserted into the circular recess. 2. The electrical connection device for an ignition coil and an ignition plug of an internal combustion engine according to claim 1, wherein the diameter of the inner circumference of the concentric circular recess on the end face of the high voltage terminal is determined by the one end face of the coil spring. An electrical connection device for an ignition coil and an ignition plug of an internal combustion engine, wherein an outer diameter of the coil is slightly smaller than an outer diameter of the coil, and a spiral portion of one end of a coil spring is brought into contact with an annular portion of the end face.