Abstract: A brushless motor includes a stator comprising a stator core with teeth protruding inwardly and windings wound on the teeth, and a rotor comprising a shaft, a rotor core fixed to the shaft, and a ring magnet fixed to the circumferential outer surface of the rotor core. The ring magnet includes a plurality of magnetic poles radially magnetized so that north poles and south poles are arranged alternately in the circumferential direction, boundary lines between adjacent magnetic poles being skewed by an angle ? relative to an axis of the shaft. A plurality of grooves are formed in a circumferential outer surface of the rotor core. Each groove extends from one axial end to the other axial end of the rotor core, has a circumferential width smaller than each of the magnetic poles, and is covered by the ring magnet with a void formed between the groove and the ring magnet.

Abstract: A brushless motor has a stator and a rotor rotatably installed inside of the stator. The stator includes a stator core with teeth protruding inwardly and windings wound on the teeth. The rotor includes a shaft, a rotor core fixed on the shaft, and a ring magnet fixed to the circumferential outer surface of the rotor core. The magnet includes a plurality of magnetic poles radially magnetized so that north poles and south poles are arranged alternately in the circumferential direction. Boundary lines between magnetic poles are skewed by an angle relative to an axis of the shaft.

Abstract: A brushless motor includes a stator comprising a stator core with teeth protruding inwardly and windings wound on the teeth, and a rotor comprising a shaft, a rotor core fixed to the shaft, and a ring magnet fixed to the circumferential outer surface of the rotor core. The ring magnet includes a plurality of magnetic poles radially magnetized so that north poles and south poles are arranged alternately in the circumferential direction, boundary lines between adjacent magnetic poles being skewed by an angle ? relative to an axis of the shaft. A plurality of grooves are formed in a circumferential outer surface of the rotor core. Each groove extends from one axial end to the other axial end of the rotor core, has a circumferential width smaller than each of the magnetic poles, and is covered by the ring magnet with a void formed between the groove and the ring magnet.

Abstract: A brushless motor has a stator and a rotor rotatably installed inside of the stator. The stator includes a stator core with teeth protruding inwardly and windings wound on the teeth. The rotor includes a shaft, a rotor core fixed on the shaft, and a ring magnet fixed to the circumferential outer surface of the rotor core. The magnet includes a plurality of magnetic poles radially magnetized so that north poles and south poles are arranged alternately in the circumferential direction. Boundary lines between magnetic poles are skewed by an angle relative to an axis of the shaft.