Patent ID: 7789565

Claim:
A fluid dynamic bearing apparatus comprising: a hydrodynamic groove region in which a plurality of hydrodynamic grooves are arranged; a smooth surface opposing the hydrodynamic groove region; and a bearing gap disposed between the hydrodynamic groove region and the smooth surface and in which a fluid dynamic pressure is produced by relative rotation between the smooth surface and the hydrodynamic groove region, wherein the hydrodynamic groove region includes first and second roll-over portions, the roll-over portions being generated when the hydrodynamic groove region is formed by thrusting a pattern corresponding to the shape of the hydrodynamic groove region so as to carry out plastic processing such that the first and second roll-over portions are disposed at first and second ends of the hydrodynamic groove region, respectively, and the smooth surface is defined by a step so as to have a length shorter than a length of the hydrodynamic groove region so that the smooth surface opposes the hydrodynamic groove region except at the first and second roll-over portions of the hydrodynamic groove region.