Patent ID: 7602582

Claim:
A fluid dynamic bearing system, particularly for the rotational support of a spindle motor, comprising: a sleeve-shaped first bearing disk ( 1 ) having a bore concentric to a rotational axis ( 22 ), a cylindrical shaft ( 2 ) disposed in the bore and connected to the first bearing disk ( 1 ) having a second bearing disk ( 3 ) disposed at one end that is arranged at a spacing to the first bearing disk ( 1 ) such that an annular disk-shaped space is formed between the first and the second bearing disk; a third annular bearing disk ( 4 ; 24 ) that is disposed in the annular disk-shaped space and is rotatable about the rotational axis ( 22 ), the opposing surfaces of the first, the second and the third bearing disk ( 1 ; 3 ; 4 ) as well as the shaft ( 2 ) being separated from one another by a bearing gap ( 5 ) filled with bearing fluid; at least one radial bearing ( 6 ) formed by the opposing circumferential surfaces of the shaft ( 2 ) and the third bearing disk ( 4 ; 24 ) and the hydrodynamic bearing patterns ( 7 ) associated with these circumferential surfaces, a first axial bearing ( 8 ) formed by the opposing end faces of the first and the third bearing disk ( 1 ; 4 , 24 ) and the hydrodynamic bearing patterns ( 9 ) associated with these end faces, and a second axial bearing ( 10 ) formed by the opposing end faces of the second and the third bearing disk ( 3 ; 4 , 24 ) and the hydrodynamic bearing patterns ( 11 ) associated with these end faces, wherein the bearing system forms a part of a spindle motor, the third bearing disk ( 4 ; 24 ) being connected to a hub ( 12 ; 16 ; 25 ) of the spindle motor at its outside circumference, and wherein an annular space ( 20 ) connected to the bearing gap ( 5 ) and tapering in the direction of the bearing gap is disposed between a surface of the inside circumference of the hub ( 12 ; 16 ; 25 ) and an opposing surface of the outside circumference of the first bearing disk ( 1 ), the annular space being at least partly filled with bearing fluid.