Patent ID: 7374341

Claim:
A hydrodynamic bearing arrangement for an electric spindle motor, the bearing arrangement comprising a shaft ( 1 ), a bearing bush ( 2 ) and a thrust plate ( 4 ) disposed fixedly on the shaft, the shaft and the thrust plate rotating with respect to the bearing bush, and grooved patterns ( 8 ; 10 ) to generate fluid-dynamic pressure being provided on the thrust plate and/or the surfaces located opposite the thrust plate of the bearing sleeve ( 2 ) and/or a cover plate ( 5 ), and each grooved pattern ( 8 ; 10 ) comprising a total number g of grooves ( 9 ; 11 ) distributed over the surface of the thrust plate, the bearing sleeve or the cover plate, and in the shaft and/or in the thrust plate, a total number h of holes and/or recesses ( 7 ) being provided at an inner edge of the thrust plate and/or at an outer edge of the shaft, wherein the number g of grooves ( 11 ) cannot be integrally divided by the number h of recesses ( 7 ) or holes and that h cannot be integrally divided by g, characterized in that the greatest common divisor (GCD) of the natural number g and h is the digit 1.