| 摘要 |
A sintered ring magnet ( 10 ) is produced through processes of magnetically orienting magnetic powder by applying a magnetic field, pressing the magnetic powder and sintering a ring-shaped powder compact ( 30 ) thus formed. The sintered ring magnet ( 10 ) has a generally cylindrical outer surface with surface corrugations formed by alternating hollows ( 11 ) and protrusions ( 12 ) at regular intervals around the sintered ring magnet ( 10 ) at least in part along an axial direction thereof, wherein the sintered ring magnet ( 10 ) varies in cross-sectional shape from one position to next along the axial direction, and magnetic poles are formed along the surface corrugations with boundaries of the magnetic poles located in the hollows ( 11 ). The hollows ( 11 ) and the protrusions ( 12 ) are skewed about a longitudinal axis of the sintered ring magnet ( 10 ). The surface corrugations are shaped into a wavy pattern expressed approximately by absolute values of a sine wave.
|
