Patent ID: 7345392
Filing Date: 2008-03-18
Classification: F16C,H02K

Abstract:
1. A spindle motor having a hydrodynamic bearing system, particularly to drive platters in a hard disk drive, the platters being disposed on a rotor ( 5 ; 5 ′), and the bearing system being formed by a bearing sleeve ( 3 ; 3 ′; 3 ″) arranged on a baseplate ( 1 ) and a shaft ( 4 ; 4 ′) rotatably supported in an opening in the bearing sleeve and at least one thrust plate ( 11 ; 11 ′) connected to the shaft, a liquid lubricant being filled into a bearing gap ( 8 ; 8 ′) formed between the shaft, the thrust plate and the bearing sleeve, wherein an annular space ( 13 ) is located between an outside diameter of the thrust plate ( 11 ; 11 ′) and an adjacent inside diameter of the bearing sleeve ( 3 ; 3 ′), the annular space ( 13 ) being tapered and widening in the direction towards the axial end of the bearing sleeve ( 3 ; 3 ′) facing the rotor ( 5 ; 5 ′) and which is at least partly filled with lubricant and forms a reservoir and an equalizing volume for the lubricant, and a cavity ( 17 ) connected to the bearing gap ( 8 ) and provided at the closed end of the bearing is connected via connecting channels ( 18 ; 19 , 19 ′) to an annular groove ( 12 ) which is directly connected to the tapered annular space ( 13 ), and the thrust plate ( 11 ; 11 ′) rests directly against the rotor ( 5 ; 5 ′) and is accommodated in an annular recess in the bearing sleeve ( 3 ; 3 ′; 3 ″) facing the rotor such that the thrust plate rests directly against the bearing sleeve when the motor is stationary.