Fluid dynamic bearing system to rotatably support a spindle motor

Abstract

The invention relates to a fluid dynamic bearing system for the particular purpose of rotatably supporting a spindle motor used to drive the disk(s) of a hard disk drive having a stationary shaft, a thrust plate connected to the shaft, a bearing sleeve rotatable about the rotational axis of the shaft and a cover sealing the bearing sleeve, wherein the surfaces of the shaft, the thrust plate, the bearing sleeve and the cover, that face each other and are separated from each other by a fluid-filled bearing gap, form at least one radial bearing region and at least one axial bearing region. According to the invention, the shaft is designed as a hollow shaft, and the cover has a cylindrical section concentric to the rotational axis that is rotatably accommodated in the hollow shaft in such a way that between the inside diameter of the hollow shaft and the outside diameter of the cylindrical section of the cover, an inner bearing gap filled with bearing fluid is formed, the inner bearing gap being connected to the outer bearing gap.

Dependencies are inferred from the claim text.