| 摘要 |
PROBLEM TO BE SOLVED: To miniaturize a motor and to reduce the amount of magnets to be used, by constituting a permanent magnet synchronous motor by the number of poles within a specific range, and at the same time by operating the motor at the maximum speed within the specific range. SOLUTION: The output of a motor is nearly determined according to the product of the torque and the speed of the motor. More specifically, when the maximum speed of the motor is set to 12,000 rpm, the weight W of the motor can be reduced at least by 30% as compared with a case when the motor speed is 8,000 rpm. Also, the best driving efficiency η can be obtained at approximately 8,000-20,000 rpm, thus increasing the maximum speed of the motor to approximately 12,000-20,000 rpm for reducing the weight W of the motor. Also, the number of poles is increased for reducing the amount of flux per pole and the thickness of a magnet being determined based on demagnetization is thinned for reducing the amount of the magnet Wmg to be used. More specifically, when the number of poles is changed from 8 to 12, the amount of the magnet Wmg to be used can be reduced at least by 30%. The best driving efficiency η can be obtained in the case of 8-16 poles. Therefore, the number of poles should be set to approximately 12 to 16, thus miniaturizing the motor and reducing the amount of the magnet to be used and the loss of the a driving system. |
