JPH0828422A - Ignition distributor for internal combustion engine - Google Patents

Abstract

PURPOSE:To control noise by forming at least one of tip parts of a rotor electrode and a side electrode in a composition where silicon resin is used as a binder and almina is added. CONSTITUTION:The rotor 3 of a distributor has a rotor electrode 5 composed of brass stuck onto the upper face of an insulating member 4, and a side electrode 8 in the peripheral edge of a central terminal 7. A composite substance composed of Al2O3 80-90vol% and silicon resin serving as a binder is used for at least a part of the conductive body of the rotor electrode 5 and the side electrode 8. The composite substance is soft and excellent in processability, and when it is heated after forming, the silicon resin turns into a siloxane compound having Si-O-Si connection and sharply improve heat resistance, and when it is heated above 500 deg.C, the siloxane compound turns into almina system ceramics. Thus excellent durability can be obtained, and radio wave noise emitting source is directly shut off for obtaining a sufficient preventing effect to the radio wave noise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for suppressing noise radio waves generated from an ignition device of an internal combustion engine, and more particularly to suppressing noise radio waves generated between a rotor electrode and a side electrode constituting a distributor. The present invention relates to an ignition distributor for an internal combustion engine.

[0002]

2. Description of the Related Art FIG. 1 shows an example of an ignition distributor for internal combustion engine of this type which is generally known in the past. Reference numeral 1 denotes a housing, and the housing 1 is mounted on an internal combustion engine together with a cam shaft 2 housed inside the housing. The cam shaft 2 rotates in conjunction with the crank shaft of the internal combustion engine and drives the rotor 3. The rotor 3 has an insulating member 4 connected to the cam shaft, and a rotor electrode 5 made of brass or the like fixed to the upper surface of the insulating member 4. Reference numeral 6 denotes a cap mounted on the housing 1, which has a central terminal 7 and side edges 8 of which the number corresponds to the number of cylinders of the internal combustion engine. Between the center terminal 7 and the rotor electrode 5, a center carbon 1 is provided via a spring 9.
0 is arranged, and the center carbon 10 is constantly in pressure contact with the rotor electrode 5 by the spring 9. In the ignition distributor configured as described above, the high voltage generated in the ignition coil is supplied to the central terminal 7 through the high voltage cable. This high voltage is guided to the rotor electrode 5 via the spring 9 and the center carbon 10, and the rotor electrode 5 and the side electrode 8 are further guided.
The high voltage introduced to the rotor electrode 5 dielectrically destroys the air in the discharge gap G between the tip portion 11 of the rotor electrode 5 and the side electrode 8 every time when and face each other. The voltage is distributed. Then, a high voltage is supplied to the spark plug via the high voltage cable.

By the way, in this type of ignition device, a large current having a steep rise time flows during spark discharge of the ignition distributor.
As a result, a large amount of harmful high-frequency components are generated, and these are radiated to the outside through a high-voltage cable or the like as an antenna and become noise electric waves. The noise radio waves caused by the spark discharge may interfere with communication relations such as televisions and radios, and some countries regulate the noise radio waves generated from this type of automobile by law.

Further, this noise radio wave not only affects communication, but also affects electronic devices mounted in automobiles, such as electronically controlled fuel injection devices, electronic antiskid devices, and electronically controlled automatic transmissions. It may also interfere with the safe driving of a car or the like. Under these circumstances, it has been desired to reduce noise electric waves generated from the ignition distributor, and various devices and equipment have been researched and developed or put into practical use.

For example, conventionally, a damping resistance is inserted in the rotor electrode to reduce the high frequency current itself, a damping resistance is also inserted in the high voltage cord between the ignition coil, the ignition distributor and the ignition plug, or the high voltage cord is made of a magnetic material. To prevent the emission of noise radio waves.

In the ignition distributor disclosed in Japanese Examined Patent Publication No. 63-14194, a silicon-based dielectric plate (for example, glass or resin-based fiber) is provided on one or both of the upper surface and the lower surface of the tip of the rotor electrode. It is proposed that a body or a cloth is used as a base and a silicon varnish is impregnated, applied or sprayed on the base to be cured).

[0007]

Among the ignition noises, in order to prevent radio noise due to high-voltage spark discharge in the ignition distributor, conventionally, a damping resistor is provided in the rotor electrode and the high-frequency current as a noise source is generated by the damping resistor. Radiation of noise radio waves is prevented by reducing itself, by inserting a damping resistor in the high voltage cord between the ignition coil and the ignition plug, or by shielding the high voltage cord with a magnetic material. However, if an excessive resistance is put in the ignition system, the ignition energy may be destroyed, so that a large damping resistance cannot be used. In addition, the high-voltage cord with the shielding material only suppresses noise emission in the high-voltage cord, and sometimes cannot suppress noise emission in the distributor, which is one of the major sources of radio waves. The inhibitory effect of was not sufficient.

An object of the present invention is to provide an internal combustion engine ignition distributor for preventing radio noise, which has a sufficient noise suppressing effect.

[0009]

The ignition distributor for an internal combustion engine according to the present invention has Al _{2 on} at least a part of a conductor of a rotor electrode.
The object was achieved by using a mixed substance containing 80 to 90 vol% of O ₃ and a binder of silicon resin.

[0010]

The mixture containing 80 to 90 vol% of Al ₂ O ₃ and the binder of silicon resin according to the present invention is soft and has good workability. When this material is heated after molding, the silicon resin changes into a siloxane compound having a Si-O-Si bond, and the heat resistance is greatly improved. Further heating to 500 ° C. or higher changes the siloxane compound into alumina ceramics. Generally, when ceramics are used for radio noise, it is generally necessary to carry out a thermal spraying process, but by using this substance, the step of the thermal spraying is not necessary and sufficient adhesion with a conductor can be obtained, and the strength of the ceramics can be obtained. Also improves.
Further, as the cloth impregnated with the substance of the present invention, a cloth such as glass fiber cloth, asbestos cloth or the like which is less likely to be deteriorated by heat due to spark discharge is used.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

In this embodiment, the metal tip portion 12 of the rotor electrode shown in FIG. 2 has a three-layer structure formed by coating or depping. After formation, it was heated to obtain a cured product.

In this embodiment, the metal tip portion 12 of the rotor electrode shown in FIG. 2 was formed into a thickness of 0.56 mm by hot pressing a glass fiber cloth impregnated with the substance. This was punched into a predetermined shape and size using a die and bonded to the metal tip portion 12 using an adhesive to form a three-layer structure.

In this embodiment, the tip portion 12 of the rotor electrode shown in FIG. 3 is shaped to wrap around. After forming, it was heated and used.

Further, in the present embodiment, the metal tip portion 12 of the rotor electrode may be adhered by using an adhesive agent, and by additionally using a damping resistor for the rotor, noise prevention can be enhanced.

The scope of application of the present invention is not limited to the distributor rotor of an automobile internal combustion engine, but can be applied to a distributor rotor of a high pressure spark ignition engine for vehicles other than automobiles or for non-vehicles such as generators.

[0017]

INDUSTRIAL APPLICABILITY The present invention is an ignition distributor for an internal combustion engine, in which the metal tip portion of the rotor electrode is covered with a composition containing 80 to 90 vol% of Al ₂ O ₃ and a binder of silicon resin. The composition is soft and can be freely processed, and when heated, it becomes a siloxane compound to improve heat resistance. Further, even if the discharge heat is partially increased, it is transformed into alumina-based ceramics without deterioration and excellent durability is obtained. Therefore, the radio noise radiation source is directly shielded, and a sufficient radio noise prevention effect can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a conventional internal combustion engine ignition distributor.

FIG. 2 is an explanatory diagram in which a metal tip portion of a rotor electrode has a three-layer structure.

FIG. 3 is an explanatory diagram of a shape in which a metal tip portion of a rotor electrode is entirely covered.

[Explanation of symbols]

 5 ... Rotor electrode, 12 ... Metal tip part.

Claims (1)

[Claims] 1. An ignition coil having a rotor electrode rotating in conjunction with rotation of an ignition distributor for an internal combustion engine, and a plurality of side electrodes facing the rotor electrode with a predetermined gap therebetween. In a distributor for an internal combustion engine configured to supply and distribute a high voltage to a spark plug connected to the side electrode via discharge between the rotor electrode and the side electrode, at least one of the rotor electrode and the side electrode An ignition distributor for an internal combustion engine, characterized in that the tip portion of the is formed with a composition containing alumina as a binder of silicone resin.