Patent ID: 8379345

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 and extending in a vertical direction; an upper thrust portion extending radially outward from an upper portion of the shaft portion; 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; 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, an upper surface arranged to define a fourth gap together with a lower surface of the upper thrust portion, and a communicating hole arranged to extend through the flange portion from the upper surface to the lower surface thereof; an upper hub annular portion arranged above an outer edge portion of the flange portion; and a lower hub annular portion arranged below the outer edge portion of the flange portion; the upper thrust portion and the upper hub annular portion are arranged to together define a fifth gap that is continuous with the fourth gap therebetween; the outer tubular portion and the lower hub annular portion are arranged to together define a sixth gap that is continuous with the third gap therebetween; the fifth gap includes an upper surface of a lubricating oil located therein, while the sixth gap includes a lower surface of the lubricating oil located therein; the communicating hole and a space extending from the fifth gap to the sixth gap through the fourth gap, the first gap, the second gap, and the third gap are continuously filled with the lubricating oil; and the first gap includes a dynamic pressure bearing provided therein.