JPH08145148A - Resin made pulley - Google Patents

Abstract

PURPOSE: To provide a pulley of phenol resin in which the dimensional accuracy and strength are well balanced, by including as inorganic base material a specific quantity of glass fiber and a specific quantity of mica powder in a novolak type phenol resin. CONSTITUTION: As a filler for novolak type phenol resin, inorganic base materials such as glass fiber and mica powder are used to form a resin pulley. The content of glass fiber should be 130 to 300 parts by wt. for 100 parts by wt. phenol resin. Under 130 parts allows the brittleness as one defect of phenol resin to appear, while over 300 parts causes enlargement of the partial change of the molding dimension in post-shrinkage due to the heat when it is used as a puley. The mean particle size of mica powder should be below 100μm and the content be 60-200 parts by wt. for 100 parts by wt. phenol resin, wherein under 60 parts gives insufficient improvement for the post-shrinkage due to mica powder while over 200 parts presents a problem of strength drop resulting from the lesser content of glass fiber.

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a resin pulley (including a toothed pulley) suitable as an engine part for automobiles and the like.

[0002]

2. Description of the Related Art As one of cost reduction and weight reduction of mechanical parts such as automobiles, various pulleys are replaced with resin from metal. These pulleys are required to have heat resistance, strength, dimensional stability, and abrasion resistance with the belt,
Toothed pulleys are particularly required to have heat resistance and wear resistance as well as dimensional accuracy and dimensional stability when heat is applied during use, as compared with other pulleys. Conventional resin pulley materials are
As a main filler for phenolic resin, (1) a piece of cotton cloth containing an organic base material such as wood powder, (2) a combination of glass fiber and an inorganic substance (for example, silica, calcium carbonate, talc, clay, etc.) The thing containing the thing is examined. However, in (1), since the organic base material is used, abrasion to the belt is good, but there is a problem that dimensional stability and heat resistance are poor.
In (2), the resin pulley is required to have dimensional accuracy (particular change in the dimension of the molded product due to anisotropy during post-shrinkage) and strength, among other automobile mechanical parts. It is necessary to balance the improvement in dimensional accuracy with inorganic base materials such as calcium carbonate, talc, and clay at a higher level than that of the phenol resin material used in conventional automobile mechanical parts.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a resin pulley using the phenol resin molding material in which the dimensional accuracy and the strength are balanced.

[0004]

According to the present invention, a glass fiber 130 is added to 100 parts by weight of a novolac type phenol resin.
~ 300 parts by weight and mica powder 60 having a particle size of 100 μm or less
The present invention relates to a phenol resin pulley excellent in dimensional accuracy, characterized in that it contains about 200 parts by weight.

The number average molecular weight of the novolac type phenolic resin used in the present invention is preferably 500 to 1,000.
If it is less than 500, the melt viscosity of the novolak resin is too low, so that the molten resin entrains the air remaining in the mold and the gas generated from the resin during the molding, causing a filling failure especially in the part where the mold has a blind alley. 100 easier
When it is 0 or more, the viscosity of the novolac resin is too high, so that the fluidity is deteriorated, and a small amount of resin as in the present invention tends to cause insufficient filling.

As the filler used, an inorganic base material such as glass fiber or mica powder is used, which has good dimensional stability against temperature change due to the low thermal expansion coefficient of the filler. It depends. The glass fiber is usually a chopped strand type having a fiber diameter of 8 to 15 μm and a fiber length of 1 to 5 mm, and the compounding amount is phenol resin 10
It is in the range of 130 to 300 parts by weight with respect to 0 parts by weight.
If the amount is less than 130 parts by weight, brittleness, which is a drawback of the conventional phenol resin, may appear and strength reduction may be a problem.
When the amount is more than the weight part, the orientation of the glass fiber causes anisotropy in the post-shrinkage due to the heat applied when the glass fiber is used as a pulley, and a partial change in the dimension of the molded product becomes large.

On the other hand, the mica powder used together with the glass fiber is a flaky powder and has an average particle size of 100 μm or less. If the particle size is larger than this, it may impair the smoothness of the molded product, or if a pinpoint gate or the like is used, the gate may be clogged. The mica powder used is in the range of 60 to 200 parts by weight with respect to 100 parts by weight of the phenol resin. If it is 60 parts by weight or less, the effect of improving the post-shrinkage due to the mica powder is not sufficient, and if it is 200 parts by weight or more, the proportion of the glass fiber in the filler becomes small, and the brittleness, which is a drawback of the phenol resin, appears, Deterioration becomes a problem.

In the present invention, the novolac resin and hexamine are used as a curing agent, the filler, the coloring agent, a release agent, a curing accelerator, etc. are blended, and mixed and kneaded using a mixing roll or the like. The material obtained by the subsequent pulverization is subjected to compression molding, transfer molding, or injection molding to obtain a resin pulley. The pulley usually has a metal insert in the center.

[0009]

The phenolic resin pulley of the present invention contains glass fiber to improve mechanical strength, and further, the glass fiber is mixed with mica powder to improve the defect that the belt is abraded and to improve dimensional stability. Has been done. Therefore, even after long-term use, the pulley itself and the mating material are hardly worn, and the dimensional accuracy and mechanical strength are good.

[0010]

EXAMPLES Examples and comparative examples will be described below. A mixture having the composition shown in Table 1 was mixed with a mixing roll and then pulverized to obtain a molding material. This molding material was compression molded to obtain a pulley and a test piece for measuring bending strength. The molding conditions are a mold temperature of 180 ° C. The characteristics of the pulley and the characteristics of the test piece are also shown in Table 1. The pulley wearability and belt wearability are 5000 rpm in air at 100 ° C with a belt mainly composed of ordinary rubber.
m, after 600 hours of motoring test, pulley,
The abrasion state of the belt was visually evaluated. Further, the dimensional stability of the pulley was evaluated by the deterioration state of the pulley in the motor ring test.

[0011]

[Table 1]

[0012]

The resin pulley of the present invention contains glass fiber and mica powder as main fillers,
The abrasion resistance is good, and the dimensional accuracy and strength are improved at the same time, so that its industrial value is extremely large.

Claims (1)

[Claims] 1. In a phenol resin pulley, 130 to 300 parts by weight of glass fiber as an inorganic base material and an average particle size of 1 per 100 parts by weight of a novolac type phenol resin.
A resin pulley comprising 60 to 200 parts by weight of mica powder having a size of 00 μm or less.