Patent ID: 7435003
Filing Date: 2008-10-14
Classification: F16C

Abstract:
1. A fluid dynamic bearing unit comprising: a sleeve including a bearing bore serving as a radial bearing, and a thrust face serving as a thrust bearing, formed around said bearing bore in a larger diameter than said bearing bore, and oriented perpendicular to a central axis of said bearing bore; a shaft inserted in said bearing bore of said sleeve so as to relatively rotate with respect to said bearing bore; and at least one flange attached to said shaft and having a face opposing said thrust face of said sleeve, wherein said flange includes at least two flange half pieces, at least one of said at least two flange half pieces includes in its surface a path formed in a radial direction and another path connecting said path in the radial direction to a region in the vicinity of an outer circumferential portion of said shaft, and at least a through hole formed in a radial direction upon combining said at least two flange half pieces with said radial path disposed therebetween, so as to connect a region in the vicinity of an outer circumferential surface of said shaft and a region in the vicinity of an outer circumferential surface of said flange; a radial dynamic pressure generating groove is formed on at least either of an inner circumferential surface of said bearing bore of said sleeve or an outer circumferential surface of said shaft; and a thrust dynamic pressure generating groove is formed on at least either of the face of said flange opposing said thrust face, or said thrust face of said sleeve; a lubricant is filled in a gap between said shaft and said bearing bore of said sleeve, and between said flange and said thrust face; and an object to be rotated is attached to either said shaft or said sleeve.