Patent ID: 8315010
Filing Date: 2012-11-20
Classification: G11B,H02K,Y10T

Abstract:
1. A spindle motor comprising: a stationary unit; and a rotary unit supported for rotation with respect to the stationary unit, wherein the rotary unit includes: a hub provided with a circular flat portion extending radially with respect to a vertically-extending center axis and having an upwardly-indented annular groove portion formed on the lower surface thereof and a cylinder portion extending downwards from an outer edge of the circular flat portion; and a substantially cylindrical magnetic member having an upper portion fixed to the annular groove portion by an adhesive agent, the hub including a first side surface opposed to an inner circumferential surface of the upper portion of the magnetic member, a second side surface opposed to an outer circumferential surface of the upper portion of the magnetic member and a ceiling surface arranged to interconnect an upper end of the first side surface and an upper end of the second side surface, the adhesive agent applied in an uncured state during a motor manufacturing process being interposed between the inner circumferential surface of the upper portion of the magnetic member and the first side surface of the hub and between the upper surface of the magnetic member and the ceiling surface of the hub, the radial distance between the inner circumferential surface of th upper portion of the magnetic member and the first side surface of the hub and the axial distance between the upper surface of the magnetic member and the ceiling surface of the hub being smaller than the radial distance between the outer circumferential surface of the upper portion of the magnetic member and the second side surface of the hub, the inner circumferential surface of the cylinder portion including a third side surface positioned below the second side surface and having an inner diameter greater than the inner diameter of the second side surface, the radial distance between the outer circumferential surface of the magnetic member and the third side surface being greater than the radial distance between the outer circumferential surface of the upper portion of the magnetic member and the second side surface.