JPS60141743A - Material composition for bearing sealant - Google Patents

Abstract

PURPOSE:To obtain titled composition capable of providing high-performance miniture bearing sealant with moderate rigidity and elasticity without using core metal by incorporating and dispersing, as reinforcing fiber, both organic and inorganic fibers in either synthetic rubber or synthetic resin. CONSTITUTION:(A) Oil- and heat-resistant rubber such as nitrile rubber or acrylic one, synthetic rubber or synthetic resin such as thermoplastic elastomer is incorporated and kneaded with (B) as reinforcing fiber, both organic fiber (pref. phenolic resin fiber, polyimide-, polyamide- or polyimide-amide fiber) and inorganic fiber (pref. carbon fiber) followed by subjecting to a cure molding machine to form a sealant. This sealant has moderate rigidity and elasticity, easily fittable to bearing with no deformation after the fitting, thus enabling seal performance to be adequately exerted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a material composition for use in bearing seals, particularly miniature bearing seals.

Conventionally, the method for manufacturing bearing sealants is to provide the desired shape of the sealant in the upper and lower molds, and then supply synthetic rubber, synthetic resin, and reinforcing core metal into the upper and lower molds. Then, the desired sealing material was obtained by taking it out from the mold.

For this reason, it is necessary to prepare multiple molds (many molds are needed at the same time to mold a large number of molds), it is difficult to obtain a large number of sealants in one molding, and mold costs are high. It was expensive and there were limits to mass production. Particularly in recent years, miniature bearings have become rapidly popular due to the miniaturization and high performance of machines, and sealing materials for these bearings have become widely used, but conventional manufacturing methods are cumbersome. Moreover, it had the disadvantage that it was expensive and could not be mass-produced. For this reason, sealing materials are often molded only from synthetic rubber or synthetic resin without using a reinforcing core metal, and recently many sealing materials have an annular labyrinth seal effect. However, when these sealing materials without a core metal are made thinner, they tend to lack strength and rigidity and end up being thicker. Furthermore, if the diameter is relatively large, it is very difficult to control the hardness. It is difficult to determine the balance between a certain degree of hardness and elasticity, and there are very severe restrictions on small sealing materials, and their molding has many problems.

The present invention provides an ideal material for molding bearing sealants with appropriate hardness and elasticity using conventional molding methods.

The present invention includes nitrile rubber, acrylic rubber, fluororubber,
It is a material composition used for sealing materials for bearings, which is made by mixing and dispersing reinforcing fibers in oil-resistant and heat-resistant rubbers such as silicone rubber and epichlorohydrin rubber, and synthetic rubbers or synthetic resins such as thermoplastic elastomers commonly known as TPE. .

Organic fibers and inorganic fibers are used as the reinforcing fibers, and the organic fibers may be either thermosetting or thermoplastic resin fibers, but if thermoplastic fibers are selected, they should be oil resistant and heat resistant. . As the thermosetting resin fibers, phenolic resin fibers are particularly suitable for the purpose of the present invention, and as the thermoplastic resin fibers, polyimide, polyamide, and polyimide-amide fibers are particularly suitable.

This is because it has good adhesion to various base synthetic rubbers and synthetic resins, excellent oil resistance and heat resistance, and extremely low expansion and contraction. Therefore, the sealing material for miniature bearings has excellent dimensional accuracy and stability under various usage conditions.

Further, as an inorganic fiber, carbon fiber has excellent properties, namely, the above-mentioned oil resistance and heat resistance, and very little expansion and contraction. In this case, there is no problem when mixed or dispersed in synthetic resin, but in the case of synthetic rubber, it is necessary to consider adhesion to the synthetic rubber.

In this way, when a bearing sealing material is molded only from materials such as synthetic rubber, thermoplastic elastomer, or synthetic resin, very strict values must be selected to obtain the desired hardness and elasticity, as described above. In other words, when the hardness was increased, the elasticity decreased slightly, and when the elasticity was increased, the hardness decreased, causing waving and sagging after fitting, but the bearing seal molded from the material composition of the present invention The material's elasticity is greatly improved by reinforcing fibers dispersed in synthetic rubber, thermoplastic elastomer, synthetic resin, etc., so a wide range of hardness can be achieved when molding it.

This makes it easy to fit and maintains elasticity and sealing performance even after fitting.

Next, examples will be shown.

Example 1゜Mid-high nitrile rubber 100 parts (N-237H manufactured by Japan Synthetic Rubber) Stearic acid 1 part Zinc white 6 parts Antioxidant 2 parts Paraffin (115°F) 2 parts Carbon black (HAF 3H) 7Q parts Sulfur 2 parts Thiazole type vulcanization accelerator 2 parts Thuram type vulcanization accelerator 1.5 parts Phenol fiber 60 parts (KP25BT manufactured by Nippon Kynor) After kneading the above composition, a sealing material was molded using a vulcanization molding machine. The bearing sealing material had a hardness of 90 to 95 on the J Engineering S hardness tester. When the obtained sealing material for bearings was subjected to an oil resistance test, the following favorable results were obtained.

Oil resistance test: :rxs #1 oil Rate of change after immersion at 100℃ x 70 hours Hardness change rate +6 or less Volume change rate -5% or less J Engineering S46 oil Rate of change after immersion at 100℃ x 70 hours Hardness change rate -5 or less Volume change rate +10% or more F Example 2゜Nitrile rubber 100 parts (Nippon Zeon DN-1032) Stearic acid 1 part Active zinc white 5 parts Anti-aging agent 4 parts Paraffin (115°F) 2 parts White carbon 80 parts Coloring Agent: 1 part sulfur 4 parts thiazole-based vulcanization accelerator 2-parts thulum-based vulcanization accelerator 1.5 parts Polyimide fiber 50 parts (Kevlar T-956 manufactured by DuPont) The above composition was vulcanized and molded in the same manner as in Example 1. As a result, a bearing sealing material with a hardness of 90 to 95 on the J Engineering S hardness tester was obtained.

When this was subjected to the same oil resistance test as in Example 1, similar excellent results were obtained.

The bearing sealing materials obtained in Examples 1 and 2 have appropriate hardness and elasticity, so when fitted into a bearing, they are easily bent and can be fitted easily, and after fitting, due to their hardness. The sealing effect was effectively demonstrated without any deformation.

As described above, according to the present invention, when a sealant for a bearing that does not use a core metal is molded using the rubber composition of the present invention, a sealant with appropriate hardness and elasticity and excellent sealing properties can be obtained. .

Patent applicant Uchiyama Kogyo Co., Ltd. 7-

Claims (1)

[Claims] A composition for a bearing sealant, which is a material used for a bearing sealant, characterized in that reinforcing fibers are mixed and dispersed in the synthetic rubber or synthetic resin of the sealant material.