JPH0115707B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a power distribution device for an internal combustion engine, and in particular, to a power distribution device for an internal combustion engine, and particularly to a power distribution device for use in an internal combustion engine. The present invention relates to a power distribution device for an internal combustion engine for suppressing power generation.

[Conventional technology]

Noise radio waves caused by spark discharge in the ignition system of an internal combustion engine such as an automobile may interfere with communications such as television and radio. Furthermore, it may cause damage to electronic equipment installed in automobiles, such as electronically controlled fuel injection devices, electronic anti-skid devices, and electronically controlled automatic transmissions, thereby impeding safe driving of automobiles. For this reason, it is desired to suppress the above-mentioned noise radio waves as much as possible.
Various methods have been researched and developed as described in the above publications.

[Problem to be solved by the invention]

However, the above-mentioned conventional techniques have not yet proposed a power distributor having a sufficient noise prevention effect.

SUMMARY OF THE INVENTION In view of the problems in the prior art described above, it is an object of the present invention to provide a power distributor for an internal combustion engine that has a sufficient noise prevention effect.

[Means to solve the problem]

The object of the present invention is to provide a rotor electrode fixed on a rotor base made of an insulator that rotates in conjunction with the rotation of an internal combustion engine, and a plurality of side electrodes facing the rotor electrode through a small gap. and
In the power distributor configured to supply power from the side electrode to a spark plug provided in each cylinder of an internal combustion engine, the rotor electrode is formed of a thin metal plate with a thickness of less than 1.0 mm, and the rotor electrode and the rotor The tips of the bases are arranged substantially flush, and an auxiliary plate made of a heat-resistant, high-resistance material with low thermal conductivity is provided between the rotor electrodes and the rotor base;
and the auxiliary plate is interposed so as to cover the entire opposing surface of the rotor electrode and the rotor base, and the tip of the auxiliary plate is configured to be substantially flush with the tip of the rotor electrode and the rotor base. This is achieved by a power distribution device for an internal combustion engine, characterized in that heat generated at the tip of the rotor electrode is prevented from being transmitted to the rotor base.

[Effect]

According to the above power distributor for internal combustion engines, the rotor electrode
By forming the metal thin plate with a thickness of less than 0.1 mm, it increases the electric field strength when voltage is applied, and also by the function of the auxiliary plate interposed between the rotor electrode and the rotor base, that is, its high resistance. , it becomes possible to significantly strengthen the electric field strength when the voltage is applied due to the residual charge effect. By making the tip of the auxiliary plate flush with the rotor electrode and the tip of the rotor base, the tip of the auxiliary plate remains at the tip of the auxiliary plate due to discharge, and when voltage is applied to the rotor electrode again, the Due to preignition (partial discharge) occurring between the rotor electrode and the tip thereof, discharge between the rotor electrode and the side electrode is likely to occur, and the discharge occurs at a relatively low voltage. moreover,
The heat shielding function of the auxiliary plate can maintain the temperature of the rotor electrode at a high temperature and increase the number of initial emitted electrons, thereby reducing the capacitance discharge current. Even if the rotor is maintained at a high temperature, the heat is not easily transmitted to the rotor base, and the rotor base is not deformed by the heat and loses its function.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

FIG. 1 is a sectional view of the main parts of a generally known power distributor. In FIG. 1, the power distributor is attached to an internal combustion engine (not shown) together with a camshaft 2 protruding into a housing 1. The camshaft 2 is connected to a crankshaft of an internal combustion engine for rotation, and is equipped with a rotor 5 comprising a rotor electrode 3 and a rotor base 4 made of an insulator to which the rotor electrode 3 is fixed. Further, a cap 10 is attached to the housing 1, and has a central terminal 7 fixed in the center and a plurality of side electrodes 6 (number corresponding to the number of cylinders) fixed in the circumferential direction. Further, the center carbon 9 is in contact with the rotor electrode 3 by a spring 8.

In the above configuration, a high voltage from an ignition coil (not shown) is introduced from the center terminal 7 via a high voltage cable (not shown), is transmitted to the rotor electrode 3 via the spring 8 and the center carbon 9, and is transmitted to the tip of the rotor electrode 3. After the air in the discharge gap G between the side electrode 6 and the side electrode 6 is dielectrically broken down and the electricity is distributed to the side electrode 6, it is sent to the spark plug via a high voltage cable (not shown).

In the above operation, the rotor electrode 3 and the side electrode 6
The spark discharge phenomenon during this period is the main source of noise in the ignition system.

In order to prevent the generation of noise radio waves due to this spark discharge phenomenon, the present invention basically reduces the thickness of the rotor electrode 3 to, for example, about 1.0 mm as shown in FIGS. 2 and 3, and 3 and the rotor base 4 of the rotor 5, there is an auxiliary plate 1 formed of a heat-resistant high-resistance material such as a silicon-based material plate or an alumina substrate.
1 and by extending this auxiliary plate 11 to the vicinity of the discharge part 13 of the rotor electrode 3, the electric field strength when voltage is applied is significantly strengthened, and its heat shielding function reduces the discharge heat generated during discharge. The function of maintaining the temperature of the rotor electrode 3 at a high temperature and increasing the number of initial emitted electrons during spark discharge, and the auxiliary plate 1
The residual charge effect of 1 reduces the capacitive discharge current.

Here, in FIGS. 2 and 3, after stacking the auxiliary plate 11 and the rotor electrode 3 on the protrusion 12 provided on the rotor base 4 of the rotor 5, the protrusion 12 is fixed by high-frequency heating caulking or the like, and the rotor 5 is assembled. This is an example of the formation.

In this configuration, if the plate thickness of at least the spark discharge portion 13 of the rotor electrode 3 is less than 1.0 mm, the capacitive discharge flow during spark discharge can be reduced as shown in FIG. 4, thereby reducing noise radio waves. In Fig. 4, the lines marked with...Γ...Γ... show examples of brass, and the lines marked with ●-●-●- show examples of stainless steel. This is because the thinner the rotor electrode 3 is, the higher the electric field strength is when voltage is applied, and the more easily it is heated by the heat generated during spark discharge.
This is thought to be due to the fact that as the temperature increases, initial electron emission becomes more active. In order to maintain the spark discharge section 13 at a high temperature, it is desirable to cover the rotor electrode 3 with a material having low thermal conductivity. In the graph of FIG. 4, the vertical axis indicates the magnitude of the current flowing through the rotor electrodes (0 dB=1 μA), and this current is proportional to the magnitude of the noise. Further, although this flowing current generally ranges from 10 to 1000 MHz, a typical 100 MHz component is shown here.

Furthermore, in the power distributor for an internal combustion engine of this embodiment, the rotor electrode 3 and the rotor base 4 are assembled more as shown in FIG. 3 than in the case where the rotor electrode 3 protrudes from the rotor base 4 as shown in FIG. Experiments have shown that the radio noise prevention effect is better when the rotor electrode 3 is on the same end surface as the rotor base 4, or rather when the electrode 3 is recessed.

However, if the electrodes 3 and the rotor base 4 are assembled at the same end surface or rather so that the electrodes 3 are retracted, the rotor base 4 near the discharge section 13 is There is a problem in that the tip end portion 14 of the stand melts or burns due to the discharge heat. In order to solve this problem, in the present invention, an auxiliary plate 11 made of a material with excellent heat resistance and low heat transfer coefficient is interposed between the electrode 3 and the insulator 4, and this auxiliary plate 11 is used for spark discharge. It extends to part 13.

Furthermore, if the auxiliary plate 11 is made of a high-resistance material such as a silicon plate, silicone rubber, or an alumina plate, which is made by impregnating a glass base fabric with silicone varnish and then hardening it under pressure and heat, the auxiliary plate 11 can be used as a material during the previous spark discharge. The charge accumulated in the electrode 11 causes a residual charge effect that increases the current near the discharge portion 13 of the electrode 3 when the next voltage is applied, and the noise reduction effect can be further improved.

Also, instead of incorporating the electrodes 3 into the rotor base 4 after molding as shown in FIGS. 2 and 3, the electrodes 3 are insert-molded into the rotor base 4 as shown in FIG. In this case, there is a problem that the thin plate electrode 3 is deformed. Another problem is that the contact portion 15 between the thin plate electrode 3 and the center carbon 9 is deformed due to long-term sliding. In order to solve these problems, the present invention adopts a structure in which the electrode 3 and the auxiliary plate 11 are reinforced by caulking with rivets 16 in advance and then insert molded.

Further, if the thickness of the auxiliary plate 11 is set to a predetermined level or more, there is a great advantage that resin can be prevented from entering the electrode tip portion 13 when insert molding is performed on the rotor base 4.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, it is possible to sufficiently suppress the generation of noise radio waves caused by discharge between the rotor electrode and the gap side electrode, and also to suppress the adverse effects caused by the high temperature heating of the rotor electrode caused by the discharge. Therefore, it is possible to provide a power distribution device for an internal combustion engine that is radio noise-proof and has excellent durability.

[Brief explanation of drawings]

Figure 1 is a sectional view of a generally known power distributor, Figure 2 is a plan view of the rotor of the power distributor according to the present invention, Figure 3 is a sectional view of Figure 2, and Figure 4 is a diagram showing plate thickness and flowing current. The related diagram, FIG. 5, is a sectional view of a rotor according to another embodiment of the present invention. 3...Rotor electrode, 4...Rotor base, 5...
Rotor, 11... Auxiliary plate, 13... Spark discharge section.

Claims (1)

[Claims] 1. A rotor electrode fixed on a rotor base made of an insulator that rotates in conjunction with the rotation of the internal combustion engine;
A power distributor comprising a plurality of side electrodes facing the rotor electrode through a small gap, and configured to supply power from the side electrode to a spark plug provided in each cylinder of an internal combustion engine, wherein the rotor The electrode is formed from a thin metal plate with a thickness of less than 1.0 mm,
The rotor electrode and the tip of the rotor base are arranged substantially flush with each other, and an auxiliary plate made of a heat-resistant, high-resistance material with low thermal conductivity is provided between the rotor electrode and the rotor base. , and is interposed so as to cover the entire opposing surface of the rotor electrode and the rotor base, and the tip of the auxiliary plate is configured to be substantially flush with the tip of the rotor electrode and the rotor base, A power distribution device for an internal combustion engine, characterized in that heat generated at the tip of the rotor electrode is prevented from being transmitted to the rotor base.