Spindle motor with fluid dynamic bearing and storage disk drive

摘要

A dynamic pressure bearing is defined in a first gap between a shaft portion and a sleeve portion. An upper seal portion extending upward and a lower seal portion extending downward are arranged radially outward of the dynamic pressure bearing. Each of the upper seal portion and the lower seal portion includes a surface including a lubricating oil located therein. The upper seal portion and the lower seal portion are arranged in communication with each other through a communicating hole defined in the sleeve portion. The communicating hole and a space ranging from the upper seal portion to the lower seal portion through the first gap are filled with the lubricating oil. The axial distance between the surfaces of the lubricating oil in the upper seal portion and the lower seal portion is arranged to be shorter than the axial distance between an upper end and a lower end of the dynamic pressure bearing.

主权项

1. A spindle motor comprising:
a stationary portion including a stator; and a rotating portion including a rotor magnet and rotatably supported by the stationary portion; wherein the stationary portion includes a shaft portion centered on a central axis and extending in a vertical direction; the rotating portion includes a sleeve portion arranged radially opposite to an outer circumferential surface of the shaft portion; the sleeve portion includes a communicating hole extending therethrough from an upper surface to a lower surface thereof; the shaft portion and the sleeve portion are arranged to together define a first gap therebetween, the first gap including a dynamic pressure bearing defined therein; an upper seal portion extending upward and a lower seal portion extending downward are arranged radially outward of the dynamic pressure bearing, each of the upper seal portion and the lower seal portion including a respective surface of a lubricating oil located therein, the upper seal portion and the lower seal portion being arranged in communication with each other through the communicating hole; the communicating hole and a space extending from the upper seal portion to the lower seal portion through the first gap are filled with the lubricating oil; and an axial distance between the surface of the lubricating oil in the upper seal portion and the surface of the lubricating oil in the lower seal portion is shorter than an axial distance between an upper end and a lower end of the dynamic pressure bearing.