Patent ID: 8613553

Claim:
A fluid dynamic bearing comprising: a shaft arranged along a center axis extending axially; an annular portion expanding radially outwards from the shaft; a sleeve including a top surface opposed to an under surface of the annular portion, the sleeve arranged to support the shaft and the annular portion in a relatively rotatable manner; and a lubricating fluid interposed between the shaft, the annular portion, and the sleeve, wherein the under surface includes a substantially annular edge surrounding the center axis, the substantially annular edge being radially spaced away from the shaft and the substantially annular edge being arranged radially outward from and adjacent to an axial recess defined in the under surface, a region of the under surface radially outward from the substantially annular edge is covered with a solid lubricating film, and the substantially annular edge is an edge of the axial recess, the axial recess is a substantially annular groove including sidewalls and surrounding the center axis disposed on the under surface.