Fluid dynamic bearing system for rotationally bearing spindle motor, has profiled protective cover closing opening ends of bore hole and directly lying opposite to front side of shaft, where cover includes thickness between specific ranges

摘要

The system has a bearing bushing (10) including a bearing bore hole with opening ends, and a shaft (12) arranged in the bearing bore hole. A bearing gap (16) is filled with bearing fluid and formed between an upper surface of the shaft and the bearing bore hole. A profiled protective cover (24) closes opening ends of the bearing bore hole and directly lies opposite to front side of the shaft. The protective cover includes thickness that ranges between 50 and 170 micro meters and a circular edge that rests on a front surface of the bearing bushing. An independent claim is also included for a hard disk drive comprising a data reading and writing unit.