Patent ID: 8568033
Filing Date: 2013-10-29
Classification: F16C,G11B,H02K

Abstract:
1. A motor comprising: a bearing apparatus; a stationary portion including a stationary shaft arranged along a center axis extending in a vertical direction, and a first cup portion including a circular plate portion extending radially outward from the stationary shaft; an electromagnetic stator; a rotating portion arranged to rotate about the stationary shaft; and a lubricating oil; wherein the first cup portion further includes a cylindrical portion projecting downward from an outer edge portion of the circular plate portion; the rotating portion includes: the lubricating oil is arranged in a gap between the stationary and rotating portions; at least one of the outer circumferential surface of the stationary shaft and the first inner circumferential surface of the rotating portion includes a radial dynamic pressure groove array; the outer circumferential surface of the first cup portion and the second inner circumferential surface of the rotating portion together define a tapered seal portion therebetween, the tapered seal portion having a radial dimension gradually increasing in an upward direction; an upper surface of the lubricating oil is located in the tapered seal portion; a lower surface of the lubricating oil is located between the stationary and rotating portions at a level lower than that of the annular recessed portion; the rotating portion further includes a through hole filled with the lubricating oil, one end of the through hole opening into the annular recessed portion, an opposite end of the through hole opening into the gap between the stationary and rotating portions at a level lower than that of the annular recessed portion; the electromagnetic stator is arranged radially outward from the cylindrical portion; the electromagnetic stator is arranged radially inward from the permanent magnet; and a maximum axial thickness of the cylindrical portion is greater than a minimum axial thickness of all portions of the rotating plate portion directly axially opposed to the electromagnetic stator.