Patent ID: 8711514

Claim:
A motor comprising: a rotating portion including a rotor magnet; and a stationary portion including a stator facing the rotor magnet; wherein the stationary portion includes: a shaft component including an inner shaft portion arranged around a central axis and an outer shaft portion fixed to an outer circumferential surface of the inner shaft portion; an upper plate portion defining a single monolithic member together with one of the inner shaft portion and the outer shaft portion and extending radially outward from an upper portion of the one of the inner shaft portion and the outer shaft portion; and a lower plate portion defining a single monolithic member together with the other of the inner shaft portion and the outer shaft portion and extending radially outward from a lower portion of the other of the inner shaft portion and the outer shaft portion; the rotating portion includes a sleeve portion which is disposed between the upper plate portion and the lower plate portion; a lubricating oil is continuously present between an upper thrust gap between the sleeve portion and the upper plate portion, a radial gap between the sleeve portion and the outer shaft portion, and a lower thrust gap between the sleeve portion and the lower plate portion; an upper seal portion is arranged to extend radially outward from the radial gap and between the stationary portion and the rotating portion, an upper surface of the lubricating oil being located in the upper seal portion; a lower seal portion is arranged to extend radially outward from the radial gap between the stationary portion and the rotating portion, a lower surface of the lubricating oil being located in the lower seal portion; a lower thrust dynamic pressure generating groove array is arranged on at least one surface of a lower surface of the sleeve portion and an upper surface of the lower plate portion, the lower surface of the sleeve portion and the upper surface of the lower plate portion defining the lower thrust gap; a radial dynamic pressure generating groove array is arranged on at least one surface of an inner circumferential surface of the sleeve portion and an outer circumferential surface of the outer shaft portion, the inner circumferential surface of the sleeve portion and an outer circumferential surface of the outer shaft portion defining the radial gap; the radial dynamic pressure generating groove array includes an upper radial dynamic pressure generating groove array and a lower radial dynamic pressure generating groove array; the inner shaft portion is fixed to the outer shaft portion in an interference fit; and an axial range of a fixing region of the inner shaft portion and the outer shaft portion which is in the interference fit is included in a range between the upper radial dynamic pressure generating groove array and the lower radial dynamic pressure generating groove array.