JPH08159244A - Resin pulley - Google Patents

Abstract

PURPOSE: To provide a phenol resin pulley formed in such a manner that size precision and a strength are balanced with each other by a method wherein respective specified amounts of glass fibers, mica powder, clay, and wollastonite are contained in novolak type phenol resin. CONSTITUTION: A resin pulley suitable for the engine parts of an automobile is formed of material prepared in such a manner that, based on 100 pts.wt. novolak type phenol resin, 130-300 pts.wt. glass fibers (a), 30-100 pts.wt. mica powder (b) with an average grain size of 100μm or less, and 30-100 pts.wt. one or more kinds selected from calcium carbonate, clay, and wollastonite (c), the average grain sizes of which are 10μum or less are contained. A number average molecular eight of working novolak type phenol resin is preferably 500-1000. Further, a chopped strand type with an ordinary fiber diameter of 8-15μm and a fiber length of 1-5mm glass fibers (a) is used as the glass fibers (a), and the mica powder (b) is used to suppress wear of a belt due to the glass fibers (a).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 wear resistance to the belt, but toothed pulleys have heat resistance and wear resistance, and also dimensional accuracy and dimensional stability when heat is applied during use. Is especially required as compared with other pulleys. Conventional materials for resin pulleys include (1) a piece of cotton cloth, an organic base material such as wood powder, etc. as a main filler of phenol resin, (2) glass fiber and an inorganic material (for example, glass beads, Those containing a mixture of silica, talc, etc.) are being studied. 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 the automobile mechanical parts. It is necessary to balance the improvement in dimensional accuracy by using inorganic base materials such as beads, silica, and talc in a higher dimension 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 phenol resin pulley in which the above dimensional accuracy and strength are well balanced.

[0004]

According to the present invention, glass fiber (a) is added to 100 parts by weight of a novolac type phenol resin.
130 to 300 parts by weight, 30 to 100 parts by weight of mica powder (b) having an average particle size of 100 μm or less, and an average particle size of 100 μ
Includes 1 to 2 or more (c) 30 to 100 parts by weight selected from calcium carbonate of m or less, clay, and wollastonite, and has good wear characteristics and excellent dimensional accuracy and strength in good balance. It relates to a phenol resin pulley.

The number average molecular weight of the novolac type phenol resin (hereinafter referred to as novolac resin) used in the present invention is preferably 500 to 1,000. When the viscosity is 500 or less, the viscosity of the novolac resin is too low, so that the molten resin is liable to engulf air remaining in the mold and gas generated from the resin during molding, and it is easy to cause defective filling especially in the part where the mold is a blind alley. When it is 1000 or more, the viscosity of the novolac resin is too high and the fluidity deteriorates, and in the case of a material having a small amount of resin as in the present invention, insufficient filling tends to occur.

As the filler to be used, an inorganic base material such as glass fiber (a), mica powder (b), calcium carbonate, clay or wollastonite (c) is used. This is because the coefficient of thermal expansion is lower than that of the base material, so that the dimensional stability against temperature change is good. The glass fiber (a) usually has a fiber diameter of 8 to 15 μm,
It is a chopped strand type fiber having a fiber length of 1 to 5 mm, and the compounding amount is in the range of 130 to 300 parts by weight with respect to 100 parts by weight of the phenol resin. If it is less than 130 parts by weight, the weakness of the phenol resin may appear, which may cause a problem of strength reduction. If it is more than 300 parts by weight, anisotropy occurs due to the orientation of the glass fiber, which is received when used as a pulley. The heat causes large post-shrinkage and partial dimensional change.

Since the mica powder (b) used together with the glass fiber is a flaky powder and is isotropic, it has the effect of reducing non-uniform dimensional changes and suppressing belt wear due to the glass fiber. is there. Calcium carbonate, clay and wollastonite (c) are spherical powders having an average particle size of 100 μm or less. It has been found that these inorganic base materials reduce the dimensional change together with mica powder, and have a great effect of improving the wear characteristics as compared with silica powder, glass powder, talc, etc., especially when used in combination with mica powder. It was Silica powder, glass powder, talc, and the like have similar strength and dimensional stability, but the wear characteristics deteriorate. If the particle size is larger than this, the smoothness of the molded product may be impaired, and if a pinpoint gate or the like is used, the gate may be clogged.

The mica powder (b) used is in the range of 30 to 100 parts by weight with respect to 100 parts by weight of the phenol resin, and calcium carbonate, clay or wollastonite (c) is added to 100 parts by weight of the phenol resin. 30 ~
It is 100 parts by weight. If the amount of mica powder is less than 30 parts by weight or the amount of calcium carbonate, clay or wollastonite is less than 30 parts by weight, the isotropic effect of the above mica powder, calcium carbonate, clay or wollastonite is not sufficient. The effect of improving dimensional change such as post-shrinkage becomes small, and the wear characteristics become insufficient. Mica powder exceeds 100 parts by weight, or calcium carbonate,
If the amount of clay or wollastonite exceeds 100 parts by weight, the proportion of glass fibers in the substrate becomes small, and the brittleness that is a drawback of the phenol resin appears, resulting in a problem of strength reduction. In addition, in the above-mentioned inorganic base material used together with glass fiber, as an effect for reducing a partial change in the size of the molded product, mica powder is not only isotropic but also its improvement effect due to its flaky shape. Is the largest.

In the present invention, the novolac resin and hexamine are used as a curing agent, the inorganic base material, a coloring agent, a release agent, a curing accelerator, etc. are blended, and mixed using a mixing roll or the like. The material obtained by kneading and then pulverizing 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.

[0010]

The phenol resin pulley of the present invention has good mechanical strength by containing the glass fiber (a),
Further, mica powder (b) and calcium carbonate, clay or wollastonite are blended in order to improve the defect that the glass fiber wears the belt and to improve the dimensional stability. Therefore, the pulley itself and the mating member are hardly worn, and the dimensional accuracy and mechanical strength are good.

[0011]

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. The dimensional stability of the pulley was evaluated by the deterioration state of the pulley by the motor ring test.

[0012]

[Table 1]

[0013]

The phenol resin pulley of the present invention comprises glass fiber (a), mica powder (b), calcium carbonate, clay or wollastonite (c) as the main base material.
By containing, the abrasion resistance is extremely good, and the dimensional accuracy and the strength are improved at the same time, so that the industrial value thereof is extremely large.

Claims (1)

[Claims] 1. In a phenol resin pulley, 130 to 300 parts by weight of glass fiber (a) as an inorganic base material and 30 to 100 parts by weight of mica powder (b) having an average particle size of 100 μm or less are used with respect to 100 parts by weight of a novolac type phenol resin. Parts, and one or more selected from calcium carbonate having an average particle size of 100 μm or less, clay and wollastonite (c) 30 to 100 parts by weight, and a phenol resin pulley.