JPH0121348B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a power distribution device for an internal combustion engine, and more particularly to a power distribution device for an internal combustion engine for suppressing the generation of radio noise caused by discharge between a rotor electrode and a gap side electrode facing the rotor electrode. 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. In addition, 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, which may impede safe driving of automobiles. For this reason, it is desirable to suppress the above noise radio waves as much as possible.
Various methods have been researched and developed. (For example, Publication No. 51-38853) However, at the current stage, no power distributor having a sufficient noise prevention effect has been proposed yet. An object of the present invention is to provide a power distribution device for an internal combustion engine having the above-mentioned noise prevention effect, and its characteristics are that the rotor electrode is formed of a plurality of thin sheets, and a silicon-based material is formed between the layers of the thin sheet electrodes. In this structure, an intermediate material is inserted, and this intermediate material extends to the spark discharge part. 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 consisting of a rotor electrode 3 and an insulating rotor base 4 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. The conventional silicon coating method is as shown in FIG.
2. Silicone grease 11 is applied to the entire bottom surface 14. However, this method has the disadvantage that intermittent discharge tends to occur during discharge between the rotor electrode 3 and the side electrode 6, especially in the region of inductive discharge, and noise enters the FM radio. According to the inventor's experiments, as shown in FIG. 4, silicone grease 11 is applied to at least one of the upper surface 13 and lower surface 14 of the rotor electrode 3,
It has been found that by creating a structure in which 2 is exposed, both FM radio noise and radio noise in the regular area can be reduced. Table 1 shows an example of the experimental results.

[Table] Measurement conditions (1) All rotor electrodes are brass.
(2) The side electrodes are all aluminum. However, if the silicone grease 11 is simply applied to the upper surface 13 or lower surface 14 of the rotor electrode 3 as shown in FIG. It has the disadvantage of being easily consumed by scattering and discharge heat. As an embodiment of the present invention is shown in FIG. 2, the rotor electrode 3 is formed of a plurality of thin sheets 3A, and a silicon-based material such as silicon grease 11 is applied between the layers.
By filling silicone grease 11 to the discharge surface 12 without applying silicone grease to the discharge surface 12. Furthermore, when the silicone grease 11 tries to scatter due to the centrifugal force caused by the rotation of the rotor 5, a negative pressure is created between the layers of the thin sheet 3A, and a suction force acts on the grease.
Thin plate 3A and grease 11 constituting rotor electrode 3
The adhesive force between them prevents them from scattering. Furthermore, since there is grease between the layers, wear due to discharge heat is extremely low. In FIG. 2, the rotor base 4 and the rotor electrode 3
This is done by caulking a protrusion 15 provided on the rotor base 4 using high frequency heating. Next, in addition to silicone grease as the material to be filled between the layers, other silicone-based substances such as glass base cloth are impregnated with silicone varnish and then pressurized.
Similar excellent noise prevention effects have been obtained using heat-cured silicone plates, silicone rubber, silicone oil-impregnated members, silicone adhesives, silicone tapes, and the like. This is presumed to be because, since there are metal electrodes on both sides of the silicon-based material, the electric field strength tends to locally increase when the next voltage is applied due to the residual charge accumulated in the dielectric during the previous discharge. Furthermore, the thinner the plate thickness of the electrodes 3 on both sides of the silicon-based material 11 is, the higher the electric field will be when voltage is applied, and the higher the temperature of the discharge part 12 of the electrode 3 will be, the more the initial number of emitted electrons will increase, and the voltage during discharge will be lower. By lowering it, the noise prevention effect improves. According to the inventor's experiments, when there is only one electrode, the relationship between the plate thickness and the noise prevention effect is as shown in Figure 5, and when the plate thickness of the electrode is 1.0
It has been found that the radio noise prevention effect improves rapidly when the thickness is less than mm. Here, the lines Γ...Γ... indicate brass, and the lines -●-●-●- indicate stainless steel. As described above, the present invention has the advantage that an extremely excellent noise prevention effect can be obtained due to the synergistic effects of electric field concentration due to the thin plate, activation of thermionic emission, and stray charge effect due to the silicon-based material.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a generally known power distribution section, Fig. 2 is a cross-sectional view of a rotor of a power distributor according to the present invention, Fig. 3 is a cross-sectional view of an electrode fully coated with silicon, and Fig. 4 is a top and bottom silicon Cross-sectional view of the electrode coated with
The figure is a diagram showing the relationship between electrode plate thickness and flowing current. 3... Rotor electrode, 3A... Thin plate, 11... Silicone grease, 12... Spark discharge part.

Claims (1)

[Claims] 1. A rotor electrode that rotates in conjunction with the rotation of an internal combustion engine, and a plurality of side electrodes that face the rotor electrode through a small gap, and an ignition device that is connected to each cylinder of the internal combustion engine from the side electrode. In a power distribution device configured to supply power to a plug, the rotor electrode is formed by overlapping two brass plates having a thickness of 1.0 mm or less and having the same shape, and a gap between the two brass plates. A power distribution device for an internal combustion engine characterized by comprising a laminated electrode in which a silicon-based material is interposed over the entire surface.