| 摘要 |
PROBLEM TO BE SOLVED: To provide a field element of a radially anisotropic magnetic field type motor, wherein it has superior torque to weight ratio and cogging torque of reduced markedly from the conventional case is realized. SOLUTION: In a cylindrical field magnet 1 of a motor, the mixture of anisotropic magnetic powder with a binder is shaped into a form of a ring, and its field has a radial magnetic orientation, its anti-armature side peripheral surface 12 is circular, its armature-side peripheral surface 11 has a plurality of magnetic pole surfaces 13, whose circumferential polarities are formed alternately at predetermined pitches by being magnetized radially, each magnetic pole surface 13 is protrusive furthest to the armature side in the circumferentially central portion thereof, both the adjacent boundaries of each magnetic pole surface 13 are recessed most to the anti-armature side, each magnetic pole surface 13 has a corrugated curved surface which is gradually separated from the armature of the motor as proceeding circumferentially from the central portion thereof to both the boundary portions thereof, and a maximum magnetic energy (BH) max of not less than 13 MGOe is formed in the radial direction. A field element of a radially anisotropic magnetic field type motor comprises this cylindrical field magnet 1 and a soft magnetic field yoke 2 which makes contact with the anti-armature side peripheral surface 12 of the cylindrical field magnet 1. |
