Patent ID: 7362025

Claim:
An internal permanent magnet (IPM) rotary electric machine having a rotor with a rotor core formed with a plurality of magnet accommodation cavities disposed successively circumferentially with a fixed pitch and with a plurality of permanent magnets contained with respective ones of said magnet accommodation cavities, each said magnet accommodation cavity having circumferentially opposing faces respectively extending parallel to an axial direction of said rotor, and each said magnet accommodation cavity being located inward from a circumferential face of said rotor core that is disposed opposite a stator of said rotary electric machine, said circumferential face being disposed opposite a stator core of said rotary electric machine, the rotor core further formed with a plurality of flux barriers for blocking circumferentially-directed flows of magnetic flux of said permanent magnets, with a pair of said flux barriers disposed extending out of, or closely adjacent to, respective circumferentially opposing ends of each said magnet accommodation cavity, each said flux barrier extending radially to a position close to said circumferential face of said rotor core; wherein each said flux barrier is formed with a trench portion which extends to a deepest point within said rotor core, said deepest point being located at a greater radial distance from said circumferential face than a radial distance from said circumferential face to a deepest edge of a side face of said permanent magnet; said deepest edge being a location, on said permanent magnet side face, that is at a maximum radial distance from said circumferential face, wherein said each flux barrier is shaped substantially as a triangle, as seen in a cross-section taken in a plane at right angles to said rotor axis direction, said triangle having a first apex, corresponding to said deepest edge, a second apex, corresponding to said deepest point of said trench portion, and a third apex, corresponding to a point of intersection between an outer side face of said flux barrier and a tangent line that extends from said deepest edge and is tangent to an imaginary circle that is centered on a central axis of said rotor and has a radius equal to the distance from said central axis to said deepest edge.