| 摘要 |
The present invention provides a grease composition which comprises a base oil and a thickening agent and in which the base oil comprises an ester oil represented by the following general formula (1) and composed of pentaerythritol and a fatty acid, the composition being characterized in that it comprises a pentaerythritol tetra-ester oil in which the fatty acid used for forming the ester, at least, comprises 2-ethyl hexanoic acid in an amount ranging from 51 to 55% by mass and caprylic acid and capric acid in a total amount ranging from 39 to 49% by mass wherein the content of caprylic acid is not less than 30% by mass and that of capric acid ranges from 5 to 10% by mass:
€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒC(CH 2 OCOR 1 ) 4 €ƒ€ƒ€ƒ€ƒ€ƒ(1)
wherein R 1 represents a linear and/or branched fatty acid residue having 6 to 12 carbon atoms as well as a bearing comprising the grease composition, filled therein. The grease composition of the present invention is suitably used in the rolling bearing under low temperature conditions and can show stable lubricating performance over a long period of time. |
