JPH01360A - ignition distributor cap - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a single ignition distributor cap.

[Conventional technology]

Conventionally, this type of ignition distributor cap has been made of thermosetting synthetic resins with good electrical insulation such as phenol resin and epoxy resin, polypropylene, polybutylene terephthalate,
Thermoplastic synthetic resins with good electrical insulation properties, such as polyphenylene sulfide, are used. Among these cap materials, those made of thermoplastic synthetic resins are widely used because they can be produced by injection molding and have the advantage of reducing product costs compared to thermosetting resins. ing. Conventional examples of this type of ignition distributor cap include 1, for example, Japanese Patent Application Laid-Open No. 14939/1983, US Pat. No. 3,404,245, and US Pat. No. 1,217,113.
There is something disclosed in the issue.

[Problem that the invention seeks to solve]

By the way, when a power distributor cap is usually molded using thermoplastic synthetic resin, glass fibers, inorganic fillers, etc. are mixed into the resin for reinforcement, which inevitably causes minute irregularities on the surface. The surface tends to become rough easily, and as a result, the following phenomenon may occur.

In other words, when the outside of a power distribution cap is cooled due to a drop in outside temperature or water being sprayed on it, moisture condenses and adheres to the roughened inner wall surface, while when power is being distributed, water condenses on the ignition coil. Since a high voltage of LOkV or more is supplied to the spark plugs of each cylinder, when moisture adhering to the inner wall of the distributor cap comes into contact with nitrogen oxides generated by corona discharge during power distribution, nitric acid is formed, and this nitric acid Due to the long-term action of the cap, the inner wall of the power distributor cap is further eroded, and as a result, the inner wall of the cap contains moisture (water wetting phenomenon), and there is a concern that the inner wall of the cap may cause creepage leakage, resulting in malfunction of the engine.

The present invention has been made in view of the above points, and its purpose is to improve the durability and soundness of the ignition distributor cap by effectively preventing the water wetting phenomenon and corona deterioration of the inner wall of the cap. It's about letting people know.

[Means for solving problems]

The above object is to provide an ignition distributor cap molded with an insulating molded resin containing at least one of a reinforcing material and a filler, in which the distributor cap is made of the same type of thermoplastic synthetic resin but with different flow characteristics. This is achieved by molding with a mixed insulation molding resin.

[Effect]

Even thermoplastic synthetic resins with different flow characteristics have compatibility in mixing as long as they are of the same type. In addition, when a power distributor cap is molded by mixing thermoplastic synthetic resins with different flow characteristics, due to the nature of the resin, the more fluid the resin, the more likely it is that the surface layer of the molded product will be formed. Those with low flow properties have properties that sufficiently compensate for the rigidity of molded products, while those with medium flow properties have high fluidity and low It has intermediate properties of fluidity and contributes to impact resistance and rigidity. As a result, by molding the distributor cap with an insulating molding resin that mixes different types of resin with different flow characteristics, the surface layer of the cap has a smooth and glossy surface, and the entire cap is rigid.

A power distributor cap having NM resistance can be obtained.

Since the cap surface layer has smoothness, even if reinforcing materials, fillers, etc. are mixed into the cap molding resin, it is possible to almost completely eliminate unevenness on the inner wall of the cap, and even if the unevenness of the inner wall of the cap is Wetting of the inner wall of the cap and corona deterioration during power distribution can be effectively prevented.

[Example] Each example of the present invention will be described below. The first to seventh examples represent the composition ratios of components constituting the power distributor cap of each example of the present invention. In each example, the degree of fluidity is expressed as a melt flow rate (melt index), and the melt flow rate is hereinafter referred to as MF.
It is abbreviated as R.

In addition, each example shows polypropylene (p
p) Alternatively, polyphenylene sulfide (PPS), reinforcing material, inorganic filler, etc. are mixed and stirred in a mixer (at this time, colorants, antioxidants, stabilizers, etc. are added), and then pelletized in an extruder. The pellets were then used for injection molding to obtain a power distributor cap. The numerical unit of MFH in each example is g/10mln.

[Example 1] PP, homopolymer (MFH25)...50 parts by weight PP, block copolymer (MFH15)...50 parts by weight PP, block copolymer (MFH2,8)...50
Parts by weight Talc...60 parts by weight [Example 2] PP, homopolymer (MFH25)...50 parts by weight pp, Block Copo IJ? -(MFH9,0)...5
0 parts by weight PP, block copolymer (MFR4,3)...50 parts by weight Glass fiber...60 parts by weight [Example 3] pp, homopolymer (MFRII)...50 parts by weight pp, block copolymer (MFR30) ...50 parts by weight PP, block copolymer (MFR2,8)...50
Part by weight Talc/Silica (1/l)...60 parts by weight [Example 4] PP (MFR25)...40 parts by weight PP
(MFR9,6) ...60 parts by weight PP
(MFR2,8) ...50 parts by weight talc
...60 parts by weight [Example 5] pps (MFR15,0) ...50 parts by weight P
PS (MFR25)...50 parts by weight Glass fiber...60 parts by weight [Example 6] Pr'S (MFR150)...50 parts by weight P
PS (VFR75) ...50 parts by weight PPS
(MFR25) ・50 parts by weight Glass fiber ・90 parts by weight [Example 7] PPS (MFR150) ・40 parts by weight PPS
(MFR25) ...60 parts by weight glass fiber
...40 parts by weight Each of the above examples 1
In order to compare with the power distributor caps 1 to 7, conventional examples (comparative examples) 1 and 2 molded from polypropylene and polyphenylene sulfide having a single flow characteristic are illustrated.

[Comparative Example 1] PP (MFR25)...100 parts by weight Talc...40 parts by weight [Comparative Example 2] PPS (MFR150)...100 parts by weight Glass fiber...60 parts by weight However, the above implementation As a result of detecting the surface roughness of the power distributor caps molded with the components of Examples 1 to 7, the surface roughness was 0.5 microns or less in each example, and the cap surface was smooth and glossy without sink marks. As a result of conducting a temperature cycle durability test similar to that used in an actual vehicle using this power distributor cap, the inner wall of the power distributor cap was smooth and free from deterioration due to ozone, nitrogen oxides, and corona discharge. It did not get wet and was able to maintain its initial state.

The durability test in this example is a temperature cycle durability test (room temperature -
+30°C/3hr to 130°C/3hr → room temperature.

One cycle was 20 cycles with a total time of 8 hours in power distribution (rotation speed 1500 rpm, 14 V/20 kV).

On the other hand, in the case of Comparative Examples 1 and 2, the average cap surface roughness was about 3.0 to 5.0 microns, and when it got worse, it was 11 microns.
The surface layer of the cap had minute irregularities on the entire surface and lacked gloss, and as a result of the same durability test as above, it was confirmed that it was slightly water-wettable and was beginning to deteriorate.

〔Effect of the invention〕

As described above, according to the present invention, by improving the smoothness of the surface of the power distributor cap, water wetting of the inner wall of the cap and corona deterioration can be effectively prevented.

The durability and integrity of the ignition distributor cap can be improved.

Claims (1)

[Claims] 1. A cap for an ignition distributor that distributes ignition voltage to each plug of an internal combustion engine, wherein the cap contains at least one of a reinforcing material and a filler, and is made of thermoplastic synthetic material of the same type. An ignition distributor cap characterized by being molded with an insulating molded resin made by mixing resins with different flow characteristics. 2. The ignition distributor cap according to claim 1, wherein the insulating molded resin is made of polypropylene having different flow characteristics. 3. The ignition distributor cap according to claim 2, wherein the polypropylene is made of homopolymer and block copolymer polypropylene having different flow characteristics. 4. The ignition distributor cap according to claim 1, wherein the insulating molded resin is a mixture of polyphenylene sulfides having different flow characteristics.