R-FE-B RADIAL ANISOTROPIC SINTERED RING MAGNET AND VOICE COIL MOTOR

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PROBLEM TO BE SOLVED : To provide an R-Fe-B radial anisotropic sintered ring magnet which constitutes the movable magnet member of a voice coil motor and also reduces an eddy current, and an efficient movable magnet type voice coil motor using it. SOLUTION : This voice coil motor is equipped with a stator member which has a cylindrical yoke and a stator member having field coils arranged around the above yoke, and a movable magnet member which has an R-Fe-B (R is at least one kind among rare earth elements including Y) radial anisotropic sintered ring magnet opposed via an air gap to the field coils and a supporting member for supporting the above ring magnet. For the above ring magnet, at least one slit each is made axially from the upper and lower edges, and the above slit has a length (Ls) shorter than the axial length (L) of the above ring magnet. COPYRIGHT : (C)2006, JPO&NCIPI