Patent ID: 8766503

Claim:
A permanent magnet embedded rotor for a rotating electric machine, the rotor comprising: a rotor core having a pair of accommodating recesses adjacently located with a bridge portion arranged between the accommodating recesses; and a pair of permanent magnets accommodated in the corresponding accommodating recesses, the permanent magnets each having a magnetic pole surface, a magnetic pole facing surface facing each of the magnetic pole surfaces, wherein the rotor core has a rotor outer circumferential surface as an outer circumferential surface, a d-axis and a q-axis defined by the rotor, each of the accommodating recesses has a magnet accommodating portion for accommodating the corresponding permanent magnet and a cavity at the q-axis side of the magnet accommodating portion, the cavities open in the rotor outer circumferential surface, the d-axis side of each of the cavities is formed by an outer cavity forming surface, a starting point of each of the outer cavity forming surfaces is located on the rotor outer circumferential surface, the outer cavity forming surfaces each intersect either the corresponding magnetic pole surface or an imaginary extended plane of the corresponding magnetic pole facing surface, the rotor outer circumferential surface includes a portion of an imaginary annular line, the starting points of the outer cavity forming surfaces are each located between the d-axis and an intersection point between the imaginary annular line and the corresponding imaginary extended plane, an endpoint of each of the outer cavity forming surfaces is located on the corresponding magnetic pole facing surface, and an end portion of each magnetic pole surface proximate to the q-axis is exposed to the corresponding cavity.