JPH03217659A - Ignition distributor cap for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent the occurrence of radio noise by providing a central electrode composed of conductive resin, which is assembled between an ignition coil and a distribution rotor. CONSTITUTION:An electrode 4 composed of conductive resin, the resistance value of which is 3 to 5kOMEGA, is used to connect a distribution contact element 3 to an ignition coil. By this constitution, high frequency noise can be reduced. In addition, conductors 7 and 8 are fixed onto the contacting sections of the electrode 4 with the distribution contact element 3 and the ignition coil. This thereby makes the respective contacting sections well conductive, thereby preventing the occurrence of corona discharge.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ignition distributor cap for an internal combustion engine, and more particularly to means for preventing radio noise generated within the distributor.

[Conventional technology]

Conventional radio noise prevention means for ignition distributors for internal combustion engines include, for example, Nippondenso Publication Technical Report Reference Number 16-075 (
As shown in the publication date October 20, 1979), it is known that a center electrode and side electrodes embedded in a power distribution cap are formed of a conductive resin to which a conductive additive such as carbon is added.

[Problem to be solved by the invention]

However, in the conventional apparatus described above, after the electrode is formed of conductive resin, a thin resin insulating layer is inevitably formed on the surface of the conductive resin (electrode surface). For this reason, if a power distribution contact is directly connected to an electrode made of conductive resin, corona discharge will occur between the electrode (conductive resin) and the power distribution contact, causing the problem that the electrode made of conductive resin will deteriorate. Therefore, an object of the present invention is to prevent deterioration of electrodes made of conductive grease for preventing radio noise.

[Means to solve the problem]

Therefore, as a means to solve the problem, the present invention provides a power distribution contact that contacts a brush that is integrated with a power distribution rotor, and a 3 to 50 kΩ that connects the power distribution contact and the ignition coil.
a center electrode made of a conductive resin having a resistance value of We propose an ignition power distributor cassob for internal combustion engines, which is characterized by fixing.

(Function) As a result, high frequency noise can be reduced by using an electrode made of conductive resin with a resistance value of 3 to 50 kΩ to connect the power distribution contact and the ignition coil. Since the conductor is fixed to the contact portion with the contactor and the connection portion with the ignition coil, it is possible to improve conduction at each of the connection portions and prevent corona discharge.

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

A first embodiment is shown in FIGS. 1 and 2. FIG. 1 is a sectional view of a main part showing the configuration of an embodiment of the present invention, and FIG. 2 is an enlarged front view of a center electrode in the power distributor shown in FIG. 1 is a resin cap that encloses the power distributor body, 2 is a carbon coil contactor whose one end is connected to the secondary high voltage terminal l2a of the ignition coil, and 3 is connected to a brush integrated with the power distribution rotor. Carbon distribution contact, 4 is coil contact 2
A center electrode connecting the power distribution contact 3 and the power distribution contact 3 is embedded and fixed in the cap l. 5 is a coil spring that presses the coil contactor 2 toward the ignition coil side; 6 is a coil spring that presses the distribution contactor toward the distribution rotor side; 7 and 8
1 is a conductive layer that is a conductor fixed to the center electrode; 9 is a brush that connects the power distribution contact 3 and the site electrode 11; and 10 is a power distribution rotor that easily distributes voltage, to which the brush 9 is fixed. A side electrode 11 is provided for each cylinder and is embedded in the cap 1. l2 is an ignition coil having a primary coil and a secondary coil, and is fixed in the ignition distributor. 13 is a rotating shaft connected to the camshaft of the engine, 14 is a signal rotor fixed to the rotating shaft 13, and 15 is an electromagnetic big amplifier that emits a signal in accordance with the rotation of the signal rotor l4.

The center electrode 4 is molded from a conductive resin having a resistance value of 3 to 50 kΩ in order to reduce high frequency noise generated by the ignition coil. The molding method will be described later. This conductive resin is made of thermoplastic resin such as polypropylene (PP) and polybutylene terephthalate (PBT).
As shown in the figure, the volume resistivity of this thermoplastic resin can be changed depending on the amount of carbon black added.

7 and 8 are conductive layers forming conductors. This conductive layer 7, 8
is a conductive paint integral molding method (for example, Japanese Patent Application Laid-Open No. 6111133
When molding the center electrode 4 made of a conductive resin, the center electrode 4 can be integrally formed over the entire surface of each contact storage hole of the center electrode 4. In this example, it is made of 88wt% Ni and 12wt% acrylic, and is approximately -
A conductive paint charged to 50 kV is electrostatically applied to portions of the preheated molding die corresponding to the conductive layers 7 and 8. Then, a conductive resin made of nylon 6-6 containing carbon black was injected into a molding die, and a center electrode 4 having a resistance value of 10 kΩ was obtained under molding conditions of a mold temperature of 115°C and a resin temperature of 270°C. ing. Note that the film thickness of the conductive layers 7 and 8 at this time is about 50 μm. Here, PBT (polybutylene terephthalate) shown in Figure 3 was used instead of nylon 6-6.
, nylon 610, and PET (polyethylene terephthalate) may also be used. The conductive layer formed by this method (
conductor) is formed integrally during center electrode molding,
The conductive layers 7 and 8 with high adhesion can be obtained by the pressure and heat during molding and the anchoring effect of the conductive paint into the conductive resin. Since no insulating layer is formed on the conductive resin surface (center electrode) to which the conductive layers 7 and 8 are fixed, corona discharge occurs at the connection between the center electrode 4 and the coil contact 2 and the connection between the distribution contact 3. can be prevented from occurring. Therefore, the center electrode is not degraded.

A second embodiment will be explained based on FIG. 4. This embodiment is the same as the first embodiment except for the method of fixing the conductive layer to the center electrode.

In the second embodiment, after molding the center electrode 4 with a conductive resin, a conductive paint serving as a conductor is applied to the center electrode 4 in FIG.
Connection part 16 between and coil contactor 2 (contactor storage hole)
A conductive layer is obtained by coating the connecting portion 17 (contact storage hole) between the center electric scraper 4 and the power distribution contact.

A third embodiment will be explained based on FIG. The difference from the first and second embodiments is that metal is used as the conductor instead of the conductive layer. The cylindrical portion 18 (contact storage hole) that becomes the connection part with the coil contact 2 in the center electrode 4 and the cylindrical part 19 (contact storage hole) that becomes the connection part with the distribution contact 3 each have excellent electrical conductivity. , for example using a metal such as copper. The metal cylindrical parts 18 and 19 are insert molded into the conductive resin (center electrode) 4. The center electrode 4 made of a conductive resin to which metal is fixed has improved conductivity at the connection portion with the coil contactor 2 and the connection portion with the power distribution contactor 3, and can prevent corona discharge.

In addition, the first to third embodiments are distributor caps for distributors with an integrated ignition coil, but in the case of a distributor camp where the ignition coil and the distributor are connected via a high-voltage cord, a cap made of conductive resin is used. A conductor may be fixed to the connection portion of the center electrode with the high voltage cord.

〔Effect of the invention〕

As described above, in the present invention, the center electrode made of conductive resin assembled between the ignition coil and the power distribution rotor has the effect of preventing radio noise, and the connection part of the center electrode with the ignition coil and the power distribution contact By fixing the conductor to the contact portion with the electrode, corona discharge at each connection portion is prevented and the center electrode is prevented from deteriorating, which is an excellent effect.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of essential parts showing the structure of a first embodiment of a power distributor for an internal combustion engine according to the present invention, FIG. 2 is an enlarged longitudinal cross-sectional view of a center electrode in the power distributor shown in FIG. 1, and FIG. FIG. 2 is a characteristic diagram of the material of the center electrode in the ignition distributor of the present invention. 4 and 5 are enlarged cross-sectional views showing the center electrode in the second and third embodiments of the present invention. 2...Coil contact, 3...Distribution contact. 4...
Center electrode, 7.8... Conductive layer forming a conductor, 18.1
9...Metal tube that serves as a conductor.

Claims (1)

[Claims] A power distribution contact that contacts a brush integrated with a power distribution rotor, and a 3 to 50 kΩ connecting the power distribution contact and the ignition coil.
a center electrode made of a conductive resin having a resistance value of An ignition distributor cap for an internal combustion engine, which is characterized by fixing.