Patent attributes
A brushless motor includes a stator and a rotor. The stator includes an annular stator core having teeth arranged with a spacing in a circumferential direction of the annular stator core; and coils wound around the teeth respectively. The rotor includes a rotor core and magnetic poles of segment magnets arranged annularly along a circumferential direction of the rotor core. The segment magnets are stacked at a plurality of stages in an axial direction of the rotor core. A length direction of each of the segment magnets is parallel with the axial direction of the rotor core. The following expression is satisfied:(2×β/P)+θ<(360/P)where P is the number of the magnetic poles of the segment magnets at each stage, β (electrical angle) is the effective pole angular aperture on the outer peripheral surface of the rotor core, and θ is the skew angle equivalent to a phase shift angle between the corresponding magnetic poles of the segment magnets at the adjacent stages.
