Patent ID: 8585290

Claim:
A fluid dynamic bearing having pressure-generating surface patterns, comprising a shaft ( 11 ) that is rotatably accommodated in a bore ( 12 ) of a bearing bush ( 10 ), the shaft comprising an end projecting from the bearing bush, wherein the shaft carries a hub at said end, wherein the bearing bush ( 10 ) and the hub ( 26 ) are rotatable with respect to one another about a common rotational axis ( 14 ), and form a bearing gap ( 16 ) filled with a bearing fluid between associated bearing surfaces, the fluid dynamic bearing further comprising an axial bearing ( 28 ) formed by a lower surface of the hub ( 26 ) in combination with an end face of the bearing bush ( 10 ), and two radial bearings ( 18 , 22 ) formed by the shaft and the bearing bush ( 10 ), the axial bearing comprising pressure-generating axial surface patterns ( 34 ; 134 ; 234 ; 334 ; 434 ; 534 ; 634 ) being disposed on a ring-shaped bearing surface ( 30 ) of the bearing bush ( 10 ) that is defined by an outer rim ( 36 ) and an inner rim ( 38 ) which is adjacent to the bore ( 12 ) of the bearing bush ( 10 ), wherein at least parts of the surface patterns ( 34 ; 134 ; 234 ; 334 ; 434 , 436 ; 534 ; 634 , 635 ) extend without interruption from the outer rim ( 36 ) to the inner rim ( 38 ) of the bearing surface ( 30 ), and the radial bearings comprising pressure-generating radial surface patterns ( 20 , 24 ) disposed on a cylindrical bearing surface of the shaft ( 11 ) and/or the bore of the bearing bush, and a recirculation channel disposed in the bearing bush connecting the ring-shaped bearing surface to an underside of the shaft, wherein the recirculation channel is disposed between a region radially inside the outer rim of the axial bearing and a region adjoining a lower radial bearing of the two radial bearings such that the said regions are fluidly connected, and such that pressure compensation of the bearing fluid within the bearing is improved, wherein the axial surface patterns ( 134 ; 234 ; 334 ; 434 , 436 ; 534 , 536 ; 634 , 635 , 636 ) take the form of spiral-shaped grooves, and wherein parts of the axial surface patterns ( 536 ; 636 ) extend with an interruption from the outer rim to the inner rim of the ring-shaped bearing surface, wherein the interruption is defined by a supporting surface ( 538 ) which is in the same plane as an uppermost bearing surface of the bearing bush ( 10 ).