Patent ID: 7102851

Claim:
A hydrodynamic bearing comprising; (a) a shaft; (b) a flange being a substantial disc and fixed on one end of said shaft; (c) a sleeve, when said shaft is inserted into its inside, allowed to revolve around said shaft and placed where a hollow provided on an inner surface of said sleeve is in the vicinity of a surface of said flange; (d) a thrust plate hermetically sealing a first opening end of said sleeve, thereby being placed close to said flange when said shaft is inserted inside said sleeve; and (e) a lubricant with which the whole of radial dynamic-pressure generating grooves provided at least one of a side of said shaft and an inner surface of said sleeve, and the whole of thrust dynamic-pressure generating grooves provided at least one of the surfaces of said flange and said thrust plate opposed to each other, are filled and covered; wherein: inequalities A<B, A<D, C<B, C<D, B<H, D<H, and G<H all hold, where A is a distance in the axial direction of said shaft between said flange and said thrust plate over said thrust dynamic-pressure generating groove and its vicinity, B is a distance in the radial direction of said shaft between a perimeter of said flange and said hollow of said sleeve, C is a distance in the axial drrection of said shaft between said flange and said hollow of said sleeve, D is a distance in the radial direction of said shaft between said shaft and said sleeve around the joint between said shaft and said flange, G is a distance in the radial direction of said shaft between said shaft and said sleeve over said radial dynamic-pressure generating groove and its vicinity, and H is a distance in the radial direction of said shaft between said shaft and said sleeve at a second opening end of said sleeve.