| 摘要 |
PROBLEM TO BE SOLVED: To reduce inertia of a rotor without increasing cogging torque or torque ripple in a brushless motor, particularly, in a spork-type IPM motor.SOLUTION: In a brushless motor 1 which is a spork-type IPM motor of a ten-electrode and twelve-slot configuration, a pseudo magnetic pole part 36 is formed between neighboring magnets 34 of a rotor 3, and a mass reduction hole 38 is provided at an inner circumferential side of the pseudo magnetic pole part 36. The mass reduction hole 38 is disposed within a predetermined region X. The region X is positioned in a central portion of the pseudo magnetic pole part 36 with a 1/4 angle width between the neighboring magnets 34, and set to a region circumferentially outside from a 1/4 radial length L of the magnet 34 from a radially inside end face 34a of the magnet 34, and radially inside of a circular arc P2 connecting outer radial side end portions 34b of the neighboring magnets 34 with a center O of the rotor 3 as a central point. |
