Patent ID: 7448805

Claim:
A thrust dynamic pressure bearing comprising: a bearing surface of a rotating-side bearing member; and a bearing surface of a fixed-side bearing member, both surfaces facing each other axiswise through a minute interspace, wherein the minute interspace is filled with lubricating oil; a plurality of dynamic pressure generating grooves are formed on at least one of the bearing surfaces of the rotating-side bearing member and the fixed-side bearing member; rotation is retained by dynamic pressure of lubricating oil being induced by means of the dynamic pressure generating grooves according to rotation of the rotating-side bearing member; and groove width G in a circumferential direction of rotation of the rotating-side bearing member, of the dynamic pressure generating groove; and width L in a circumferential direction of rotation of the rotating-side bearing member, of a land circumferentially adjacent to the dynamic pressure generating groove hold G>L in an area of 80% or more of the area in which the dynamic pressure generating grooves provided on the bearing surface are formed.