Lubricating grease composition
AssigneesKyodo Yushi Co., Ltd., Nsk Ltd.
InventorsAtushi Shibayama, Hiroshi Kimura, Youichiro Sugimori, Masao Yamamoto
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Abstract
An improved lubricating grease composition is herein disclosed, which comprises a base oil and a thickening agent, wherein the base oil comprises 50 to 100% by weight of a carbonate ester compound represented by the following general formula (I): R1O—CO—OR2 (I) wherein R1 and R2 each independently represents a saturated or unsaturated, linear or branched alkyl group having 6 to 30 carbon atoms, on the basis of the total weight of the base oil. The lubricating grease composition shows remarkably improved acoustic life and an improved frictional coefficient, as compared with those observed for conventional grease compositions.
Claims18
A spindle motor ball bearing lubricated with a lubricating grease composition, said lubricating grease composition comprising a base oil and a thickening agent, wherein the base oil comprises 50 to 100% by weight of a carbonate ester compound on the basis of the total weight of the base oil, said carbonate ester compound being represented by the following general formula (I):
- R1O—CO—OR2
- wherein R1 and R2 each independently represents a saturated or unsaturated, linear or branched alkyl group having 6 to 30 carbon atoms,
- wherein a simple metal soap selected from the group consisting of lithium soaps, sodium soaps, calcium soaps, and aluminum soaps, and
- wherein the amount of said thickening agent ranges from 5 to 25% by weight on the basis of the total weight of the grease composition.
A method of lubricating a ball bearing comprising
- contacting a spindle motor ball bearing with a lubricating grease composition comprising a base oil and a thickening agent, wherein said base oil comprises 50 to 100% by weight of a carbonate ester compound on the basis of the total weight of a carbonate ester compound on the basis of the total weight of the base oil, said carbonate ester compound being represented by the following general formula (I):
- R1O—CO—OR2
- wherein R1 and R2 each independently represents a saturated or unsaturated, linear or branched alkyl group having 6 to 30 carbon atoms,
- wherein a simple metal soap selected from the group consisting of lithium soaps, sodium soaps, calcium soaps, and aluminum soaps, and
- wherein the amount of said thickening agent ranges from 5 to 25% by weight on the basis of the total weight of the grease composition.
Dependencies are inferred from the claim text.