JPH09286901A - Phenol resin gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phenol resin gear that has excellent wear resistance, thermal resistance, dimensional stability and is useful for electric and electronic machines and equipment, and the like by molding a specific phenol resin material for molding without compounding fiberglass into the resin. SOLUTION: This phenol resin gear is obtained by compression molding or injection molding of a phenol resin molding material comprising the following components: (A) 100 pts.wt. of a phenol resin, (B) 200-250 pts.wt. of wollastonite, (C) 40-80 pts.wt. of natural organic fiber, (D) 5-30 pts.wt. of graphite and (E) 30-70 pts.wt. of powder silica. In addition, it is preferable to use, as component (A), a novolak or resol type of phenol resin, etc., as component (B), wollastonite of particle size of 10μm to 300μm or so, and as component (C), natural organic fiber having fiber length of 1mm or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phenol resin gear formed by compression molding or injection molding of a phenol resin molding material having excellent wear resistance, heat resistance and dimensional stability.

[0002]

2. Description of the Related Art Conventionally, gears made of a thermoplastic resin are often used as gears for electric and electronic equipment. Thermoplastic resins have been used in place of metal gears because they have excellent properties in terms of moldability, toughness, and wear resistance. However, the thermoplastic resin has problems such as deformation and dimensional change under heat, melting in some cases, and inferior transfer accuracy of mold size. The gear used was a metal gear. On the other hand, metal gears are used as gears in all fields, but there are problems in terms of workability, high cost, heavy weight, and noise. On the other hand, phenol resin has excellent heat resistance,
From the aspect of dimensional accuracy and dimensional stability, it is used for mechanical parts such as automobiles and industrial equipment. In particular, a phenol resin molding material containing glass fibers has excellent mechanical strength other than the above, and is therefore used in severe parts around the engine of an automobile. However, since the phenol resin molding material containing such glass fiber has remarkably poor wear characteristics, it is almost impossible to use it in a portion such as a gear which requires wear resistance.

[0003]

The present invention provides a resin gear formed by molding a phenol resin molding material having excellent wear resistance, heat resistance and dimensional stability without compounding glass fibers. is there.

[0004]

According to the present invention, a phenol resin molding material containing phenol resin and silica as a filler, natural organic fiber, graphite, and powder silica is formed by compression molding or injection molding. The present invention relates to a molded resin gear.

As the phenol resin, either a novolac type phenol resin or a resol type phenol resin may be used. Depending on the case, these two types may be used in combination. As the resol-type phenol resin, either dimethylene ether type or methylol type may be used. When a novolac type phenol resin is used, hexamethylenetetramine or the above-mentioned resol type phenol resin is used as a curing agent.

The silica stone preferably has a particle size of 10 μm to 300 μm. If it is less than 10 μm, workability is deteriorated when the composition is used as a molding material, and if it exceeds 300 μm, orientation occurs during molding, resulting in anisotropic difference in mechanical strength and poor dimensional accuracy, which is not preferable. Silica stone is phenolic resin 100
It is preferable to mix 200 to 250 parts by weight with respect to parts by weight. If it is less than 200 parts by weight, abrasion resistance and dimensional accuracy will be reduced. If it exceeds 250 parts by weight, the workability during materialization is deteriorated and the fluidity during molding is deteriorated, which makes molding difficult, which is not preferable.

As the natural organic fiber, defibrated pulp, raw cotton pulp, powder pulp, crushed cloth and the like can be used.
It is desirable that the fiber length be as fine as 1 mm or less, depending on the defibration degree, dispersion degree, bulkiness of the molding material and the like when formed into a molding material. The amount of the natural organic fiber is preferably 40 to 80 parts by weight with respect to 100 parts by weight of the phenol resin. Four
If it is less than 0 parts by weight, the wear characteristics are deteriorated, which is not preferable. Further, if it exceeds 80 parts by weight, the heat resistance is lowered, and the molding shrinkage ratio is increased, and the dimensional stability is lowered, which is not preferable.

The graphite may be natural or artificial, and may be scale-like, earth-like, lump-like or granular graphite. The blending amount of graphite is preferably 5 to 30 parts by weight with respect to 100 parts by weight of the phenol resin. If the amount is 5 parts by weight or less, the wear characteristics are deteriorated, which is not preferable. On the other hand, if it is 30 parts by weight or more, the mechanical strength is lowered, which is not desirable. In the present invention, powdered silica is also added. The powdered silica may be natural or synthetic silica, and its particle size is preferably 10 μm or less. Phenol resin 1
30 to 70 parts by weight is preferable with respect to 00 parts by weight. It is known that powdered silica improves wear characteristics when used in combination with organic natural fibers (JP-A-60-12464).
No. 6, Japanese Patent Application No. 4-214199).

A resin gear is obtained by compression molding or injection molding of such a molding material composed of a phenol resin and a filler.

In the present invention, since the silica stone used is acicular crystals, it is possible to obtain not only excellent mechanical strength characteristics due to the same effect as glass fiber but also abrasion resistance as compared with glass fiber. It has excellent properties. Therefore, even if a large amount of silica stone is blended, the mechanical strength is not lowered, the dimensional stability equivalent to that of glass fiber is maintained, and the abrasion resistance is not impaired. In addition, it is known that the combination of organic natural fiber and powdered silica improves wear characteristics. Furthermore, by using graphite in a range where mechanical strength does not decrease, further wear can be achieved without reducing mechanical strength. It is possible to improve the characteristics. With such a composition, a phenol resin molding material having excellent wear resistance, heat resistance and dimensional stability can be obtained. A resin gear having excellent wear resistance, heat resistance, and dimensional stability can be obtained by compression molding or injection molding of such a molding material.

[0012]

Next, the present invention will be described based on examples and comparative examples. In Example 1, 100 parts by weight of phenolic resin and 200 parts by weight of silica stone, 30 parts by weight of graphite (earth-like), 60 parts by weight of organic natural fiber, 30 parts by weight of powdered silica, and others (lubricant, coloring agent , Curing catalyst) in an amount of 5 parts by weight by injection molding. Comparative Example 1 contains 100 parts by weight of phenol resin and 2 parts of glass fiber.
A gear molded by injection molding of a material containing 5 parts by weight of 00 parts by weight and others (lubricant, colorant, curing catalyst).
Comparative Example 2 is a gear formed by injection molding a material in which 43 parts by weight of glass fiber is mixed with 100 parts by weight of 6,6-nylon resin.

Phenolic resins used in Examples and Comparative Examples,
The filler is as follows. Novolac resin: Number average quantity 900 Silica stone: Average particle size 50 μm Organic natural fiber: Average fiber length 0.5 mm Graphite: Natural earth powder silica: Average particle size 3 μm Table 1 shows the test results using these gears. .

[0014]

[Table 1]

[0015]

EFFECTS OF THE INVENTION A resin gear formed of a phenolic resin molding material using silica stone, organic natural fiber, graphite and powdered silica according to the present invention has excellent wear resistance, heat resistance and dimensional stability. Excellent resin gear.

Claims (3)

[Claims] 1. A resin gear made by molding a phenol resin molding material containing a phenol resin and silica wollaston, natural organic fiber, graphite, and powder silica as a filler. 2. With respect to 100 parts by weight of the phenol resin,
Molding a phenolic resin molding material containing 200 to 250 parts by weight of the silica stone, 40 to 80 parts by weight of the natural organic fiber, 5 to 30 parts by weight of the graphite, and 30 to 70 parts by weight of the powdered silica. The resin gear according to claim 1, wherein 3. The resin gear according to claim 1, wherein the phenol resin molding material is molded by compression molding or injection molding.