Patent ID: 7654743
Filing Date: 2010-02-02
Classification: F16C

Abstract:
1. A bearing assembly utilizing a fluid dynamic pressure for use in an electric motor, comprising: a shaft provided at a first end with a flange portion extending outwardly from a center axis of the shaft; an approximately cylindrical sleeve member inserted onto the shaft and having a first end surface opposed to the flange portion and a second end surface opposite to the first end surface; a radial dynamic pressure bearing mechanism disposed between an outer peripheral surface of the shaft and an inner peripheral surface of the sleeve member; and a thrust dynamic pressure bearing mechanism including a thrust dynamic pressure groove provided in a surface of the flange portion opposed to the sleeve member, the thrust dynamic bearing mechanism being disposed between the first end surface of the sleeve member and the flange portion; wherein the sleeve member includes a through hole provided therein, and the through hole extends between the first end surface of the sleeve member and the second end surface of the sleeve member or a portion of the radial dynamic pressure bearing mechanism on a side of the second end surface of the sleeve member, the through hole forming a circulation path continuously filled with lubrication oil together with a gap in the radial dynamic pressure bearing mechanism and a gap in the thrust dynamic pressure bearing mechanism, the through hole having an end which is superposed on the thrust dynamic pressure groove during rotation of one of the sleeve member and the flange portion with respect to the other.