US Patent 9595851 Rotary electric machine

Permanent magnets that form individual magnetic poles are configured by arranging three magnet blocks to be spaced apart from each other circumferentially, the three magnet blocks are each formed such that cross-sectional shapes that are perpendicular to a central axis of a rotor core are radially outwardly convex, and circumferential widths are narrower in magnet blocks that are further away from a magnetic pole center, and the three magnet blocks that are arranged circumferentially are formed to have mirror symmetry relative to a plane that passes through the magnetic pole center and the central axis of the rotor core.