RING MAGNET, AND MANUFACTURING APPARATUS AND MANUFACTURING METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a ring magnet capable of reducing a harmonic component of magnetomotive force distribution for reduction in uneven torque. SOLUTION: A periodical recessed/protruding configuration is formed in the axial direction of a ring outer periphery. The center of a magnetic pole is magnetized in a protruding portion 12 in a recessed/protruding configuration so that a boundary of the magnetic poles is provided on a recessed portion 11. A direction of a magnetic orientation is directed to a point of an outer periphery side on the center line of the protruding portion connecting the center line of the ring magnet with the center of the protruding portion. If the thickness of a minimum radial direction of the recessed portion 11 of the recessed/protruding configuration of the magnet ring outer periphery is as a tmin and the thickness of a maximum radial direction of the protruding portion 12 is taken as a tmax, the tmin/tmax is 0.5 to 0.9 inclusive. Furthermore, the recessed/protruding configuration formed into the outer periphery of the ring magnet is formed obliquely by rotating a predetermined angle over the axial direction of the ring magnet. COPYRIGHT: (C)2007,JPO&INPIT