| 摘要 |
A fluid dynamic bearing device (1), comprising a dynamic pressure generating groove region (B) being provided on an inner peripheral surface (3a) of a bearing member (3), which forms a radial bearing gap, the region (B) comprising: a first region (B1) for generating a fluid dynamic pressure when the bearing member (3) and a shaft member (2) are rotated relative to each other in a forward direction; and a second region (B2) for generating a fluid dynamic pressure when the bearing member (3) and the shaft member (2) are rotated relative to each other in a reverse direction. A portion of the region (B), corresponds to an end portion on an open-to-air side of the radial bearing gap, comprises an annular projecting portion (6) provided closer to the shaft member (2) with respect to a groove bottom of each of the plurality of dynamic pressure generating grooves (4).
|
