Patent ID: 8810096

Claim:
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 extending in a vertical direction; a lower plate portion extending radially outward from a lower portion of the shaft portion; and an outer tubular portion extending upward from an outer edge portion of the lower plate portion; the rotating portion includes: an inner tubular portion including an inner circumferential surface arranged to define a first gap together with an outer circumferential surface of the shaft portion, and an outer circumferential surface arranged to define a second gap together with an inner circumferential surface of the outer tubular portion; and a flange portion projecting radially outward from the inner tubular portion, and including a lower surface arranged to define a third gap together with an upper surface of the outer tubular portion, and a communicating hole extending through the flange portion from an upper surface to the lower surface thereof; an upper seal portion is arranged radially outward of the first gap, and a lower seal portion is arranged radially outward of the second gap, 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, second, and third gaps are filled with the lubricating oil; the first gap includes a dynamic pressure bearing defined therein; and the third gap includes a dynamic pressure generation portion arranged to induce a radially inward pressure acting on the lubricating oil.