| 摘要 |
PROBLEM TO BE SOLVED: To reduce the size of a motor device of a class of 1 to 300 W. SOLUTION: In a brushless motor, a field magnet is formed of a hollow cylindrical anisotropic bond magnet 13 and subjected to quadrupole magnetization. The anisotropic bond magnet 13 has a maximum energy product four times as large as a conventional sintered ferrite magnet. By subjecting the bonded magnet to the quadrupole magnetization, the length of a magnetic path of a magnetic circuit per pole is shortened and a magnetic force contributing to torque impartment is increased. If torque is the same with the conventional torque, the length of an electromagnetic rotating body and the length of a permanent magnet are shortened. The anisotropic rear earth bonded magnet is composed of a mixture of an Sm-Fe-N system material or an SmCo system material and an Nd-Fe-B system material. In this configuration, the motor device of the class of 1 to 300 W can be reduced in size. COPYRIGHT: (C)2004,JPO
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