A spindle motor and a hard disk drive apparatus including such a motor

摘要

A spindle motor including a double row bearing apparatus (2) for supporting a rotor hub (9) rotatably on a base (1) incorporating a labyrinth seal mechanism. The bearing apparatus includes a two-stepped shaft (3) and a pair of rows of rotating balls (5a) and (5b) interposed between the shaft and a sleeve outer race (4) surrounding the shaft. A pair of inner and outer sealing plates (13a) and (13b) are provided between the sleeve outer race and an inner race (6) fitted around a reduced diameter portion (3b) of the shaft to form a labyrinth seal. A pair of inner and outer sealing plates (14a) and (14b) are also provided between the sleeve outer race and optionally an inner race fitted around an enlarged diameter shaft portion (3a) to form a labyrinth seal. The bearing apparatus avoids the necessity to incorporate an additional sealing mechanism into the motor as a separate fabrication step.