Heat resistant lithium grease composition and a small motor reduced noise bearing

Abstract

A heat-resistant noise-reduction grease and a bearing containing the grease for a small motor such as a motor for imaging equipment such as a blower fan and motor bearing for a household electrical appliance such as an air conditioner, which is eco-friendly and excellent in noise-reduction properties is provided.The heat-resistant lithium grease composition is composed of 5 to 20% by weight of a thickener and 95 to 80% by weight of a base oil, wherein long-chain fatty acid lithium soap with 26 to 32 carbon atoms and lithium soap comprising a higher fatty acid with 10 to 20 carbon atoms and / or a higher hydroxyfatty acid with one or more hydroxyl groups and 10 or more carbon atoms are used as the thickener, and the base oil contains, as a main component, polymer ester oil (A) in which 8 or more ester groups are arranged in comb tooth form on one side of chain molecules of oil constituted with 8 or more carbon atoms, which is expressed by the following general formula:(where each of R1, R2, R3 and R4 represents an alkyl group, x represents an integer satisfying x≧2, and y represents an integer satisfying y≧2).and the base oil has a viscosity (40° C.) of 30 to 100 mm2 / s.

Description

TECHNICAL FIELD[0001]The present invention relates to a heat resistant grease composition for motor bearings for small motors, particularly home electric appliances such as an air conditioner, motor bearings for imaging equipment such as blower fan and the like, and more specifically to a heat resistant, noise reduction grease sealed in a bearing for a small motor to reduce the rotation noise of the motor.BACKGROUND ART[0002]Generally the use of greases sealed in a bearing is known. The prior art shows a grease composition in which 8 or more ester groups are arranged in a comb tooth form on one side of the chain molecules of oil composed of 8 or more carbon atoms. The grease is formed by adding a urea thickener to a base oil in which a synthetic hydrocarbon oil and a synthetic ester oil are mixed in a weight ratio of 0.65-0.75:0.35-0.25. See Japanese Patent No. 3514574 and U.S. Pat. No. 5,910,470. This grease is sealed in a ball bearing that supports a belt driven pulley placed in t...

AI Technical Summary

Benefits of technology

[0005]According to the invention, a heat resistant and noise-reduction grease composition that is desirably used in a bearing for a small motor is provided. In another aspect of the invention, a sealed bearing containing the grease composition is provided which is desirably installed in small motor to reduce the rotation noise of the motor in use.

[0011]The heat-resistant lithium grease composition is desirably sealed in a small motor bearing to reduce noise. The resulting composition has superior attachment to a metal surface. As a result in use, a protective film forms quickly and evenly on the bearing metal surfaces. The protective film can be maintained at a high temperature, which contributes to a longer operating life of the bearing. Furthermore, the composition has an advantageous dispersibility and resolvability of the additives in the base oil which keeps the noise low during operation of a motor using the sealed bearing according to the invention.

Problems solved by technology

Such devices makes a quick change in its rotation speed.

This lithium-soap-ester grease, however, tends to spatter and has a problem of damaging a recording medium if it is used as is.

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