| 摘要 |
PROBLEM TO BE SOLVED: To provide a fluid dynamic-pressure bearing which can miniaturize its size in axial direction using a pair of circular cone dynamic-pressure bearings, and has a structure easily controlling the amount of lubricant fluid simultaneously, and a spindle motor using it. SOLUTION: The fluid dynamic-pressure bearing, fixed in a fixing shaft 11 in such a manner of outer fitting, comprises a pair of circular cone members 12 having circular-cone-like outer surfaces 12a which increase in their outer diameters toward axial direction base side or tip side, and a cylindrical member 13 having a pair of circular cone inner surfaces 13b facing their circular cone outer surfaces 12a. A pair of the circular cone dynamic-pressure bearings is constituted by forming a fluid dynamic-pressure generating groove 13d in the circular-cone-like inner surface 13b in such a way that a bearing gap between the circular-cone-like outer surface 12a and the circular-cone-like inner surface 13b is filled with the lubricant fluid. The lubricant fluid filling the bearing gap is consecutive across a pair of the circular cone bearings, and a pair of taper seal portions TS1, TS2, which release an interface of the lubricant fluid to atmospheric air, are prepared in both axial ends. COPYRIGHT: (C)2007,JPO&INPIT
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