SPINDLE MOTOR FOR HARD DISK DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a spindle motor which enables reduction in swinging of a shaft and has a long service life although having a thin thickness.SOLUTION: A spindle motor includes: a shaft internally inserted to a sleeve and rotating relative to a base; a hub rotating integrally with the shaft; a radial dynamic pressure bearing part formed between the shaft and the sleeve; a flange part installed on an outer peripheral portion of the sleeve to project in the radial direction; an annular wall part installed in the hub to project in a direction surrounding the sleeve; and an annular thrust ring which is installed adjacent to the flange part in the axial direction of the shaft and is fixed to an inner peripheral portion of the wall part. The spindle motor includes a lubricant filling part which contains at least a clearance between an inner peripheral surface from an upper part to a closed end of the sleeve and the shaft, a clearance between the sleeve and the hub, a clearance between the sleeve and the thrust ring and a clearance between the thrust ring and the sleeve and has only one opening end formed at a position nearer to the closed end of the sleeve from an end on the base side of the thrust ring in the rotating shaft direction to surround the radial dynamic pressure bearing part.