Nidec Corporation

Kyodo Yushi Co., Ltd.

Cosmo Oil Lubricants Co., Ltd.

Yuji Hagiwara

Takayuki Oe

Iwaki Hirooka

Ryuji Terauchi

Sayuri Tsubata

A conductive lubricating oil composition including at least one lubricating base oil selected from the group consisting of compounds represented by the following General Formula (1) and compounds represented by the following General Formula (2), and at least one conductivity imparting agent selected from the group consisting of potassium trifluoromethanesulfonate, lithium trifluoromethanesulfonate, lithium nonafluorobutanesulfonate, lithium bis(trifluoromethanesulfonyl)imide, potassium bis(trifluoromethanesulfonyl)imide, and lithium tris(trifluoromethanesulfonyl)methide, in an amount of from 0.01% by mass to 1% by mass, and having a rate of change in conductivity after storage at 120&#xb0; C. for 200 hours of 10% or less. The definitions of R, R, m and n in the formulae are as indicated in the specification. Cases of m&#x2212;n=2 are excluded. 

Conductive lubricating oil composition and spindle motor

The invention provides a lubricating oil for fluid dynamic bearing including as a base oil a monoester oil free of unsaturated bond, and having an absolute viscosity of 2.0 to 3.0 mPa&#xb7;s at 100&#xb0; C. a viscosity index of 130 or more and a pour point of &#x2212;20&#xb0; C. or less.

Lubricating oil for fluid dynamic bearing and spindle motor equipped with the lubricating oil

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Kyoto, Japan

Yuji Hagiwara