Patent ID: 7674043

Claim:
A hydrodynamic bearing rotary device, comprising: a sleeve having a bearing hole, a shaft which is inserted into the bearing hole of the sleeve so as to be relatively rotatable; a flange forming a substantially disc-like shape which is integrally attached to one end of the shaft; a hub which is attached to the other end of the shaft and has an additional member receiving surface on which an additional member can be loaded; and a thrust plate which is placed so as to oppose the flange, wherein a first gap (S 1 ) between surfaces of the flange and the thrust plate which oppose one another in an axial direction, a second gap (S 2 ) between surfaces of the flange and the sleeve which oppose one another in the axial direction, and a third gap (S 3 ) between a surface of the hub and the other end surface of the sleeve which oppose one another in the axial direction are respectively formed, the hydrodynamic bearing rotary device further comprising a communication path which connects the first gap (S 1 ) or the second gap (S 2 ) and the third gap (S 3 ) and forms a circulation passage to which a lubricant is injected together with the second gap (S 2 ) and the third gap (S 3 ), in which widths of the first through third gaps (S 1 through S 3 ) satisfy the following relational expression (1): S 3>( S 1+ S 2) (1).