| 摘要 |
Provided are a lubricating oil base oil excellent in durability and low-torque property, and a lubricating oil composition suitable for a fluid dynamic pressure bearing, an oil-impregnated porous bearing, or a dynamic pressure-type oil-impregnated porous bearing to be used in a bearing for a small spindle motor related to information equipment. Specifically, provided are a lubricating oil base oil including, as a major component, a diester represented by the following formula (1), and a lubricating oil composition including the lubricating oil base oil. In the formula, R 1 and R 2 each independently represent a 1-ethylpentyl group, an n-heptyl group, or a n-hexyl group, and when the diester in which both of R 1 and R 2 each represent an n-heptyl group or an n-hexyl group is defined as A, the diester in which one of R 1 and R 2 represents a 1-ethylpentyl group is B, and the diester in which both of R 1 and R 2 each represent a 1-ethylpentyl group is defined as C, the molar ratio of the diesters falls within a range of A:B:C=25 to 65:30 to 50:3 to 25. |
