Patent ID: 8385017

Claim:
A motor comprising: a stationary portion including a stator; and a rotating portion including a rotor magnet and being rotatably supported by the stationary portion through a lubricating oil; wherein the stationary portion includes: a shaft portion centered on a central axis extending in a vertical direction; and an upper thrust portion arranged to extend radially outward from an upper portion of the shaft portion; the rotating portion includes: a sleeve portion arranged opposite an outer circumferential surface of the shaft portion and a lower surface of the upper thrust portion; and an upper hub annular portion including a tubular portion and an annular cover portion, the tubular portion being arranged to extend upward from an outer edge portion of the sleeve portion, and arranged opposite an outer circumferential surface of the upper thrust portion, the annular cover portion being arranged to extend radially inward from the tubular portion; the lower surface of the upper thrust portion and an upper surface of the sleeve portion are arranged to together define an upper thrust gap therebetween, the lubricating oil is arranged in the upper thrust gap, the outer circumferential surface of the upper thrust portion and an inner circumferential surface of the tubular portion are arranged to together define an upper seal portion therebetween, the upper thrust gap is arranged in communication with the upper seal portion, and the upper seal portion has a surface of the lubricating oil located therein; the upper thrust portion includes: an inner cylindrical surface arranged substantially in a shape of a cylinder, arranged radially inward of the outer circumferential surface to extend in the vertical direction or substantially in the vertical direction, and including an upper end arranged at a level higher than that of an upper end of the outer circumferential surface; and an outer annular surface arranged radially outward of the inner cylindrical surface, arranged at a level lower than that of the upper end of the inner cylindrical surface, and defined by an annular surface perpendicular or substantially perpendicular to the central axis; the outer annular surface and a lower surface of the annular cover portion are arranged to together define an annular radially extending gap therebetween, the radially extending gap including an axial width smaller than a maximum width of the upper seal portion; and the inner cylindrical surface and a radially inner edge of the annular cover portion are arranged to together define an annular axially extending gap therebetween, the axially extending gap having a radial width smaller than the maximum width of the upper seal portion.