Patent ID: 7777382

Claim:
A rotor comprising; a rotor core having a rotor surface; a plurality of permanent magnets embedded in the rotor core with each of the permanent magnets defining a pole of the rotor, each pole of the rotor having a pole center and a peripheral edge section, with the peripheral edge section of each of the permanent magnets being located in a vicinity between the poles and a vicinity of the rotor surface; and a plurality of non-magnetic layers being located in a vicinity of the rotor surface at a pole center side position with respect to the peripheral edge section of each of the permanent magnets, the peripheral edge sections and the non-magnetic layers being positioned to cancel 5-th order harmonics or 7-th order harmonics of an induction voltage, the poles being disposed at every approximately constant interval, varying in a constant angle, the peripheral edge section of each of the permanent magnets and the non-magnetic layers being independent from one another, and the rotor core being interposed between them, and an angle θ 1 between the peripheral edge section of each of the permanent magnets and a position between the poles, and an angle θ 2 between a pole center side edge section in the vicinity of the rotor surface of the non-magnetic layer and the position, are determined to be 0<θ1<180/(5 ·Pn ) and 180/(5 ·Pn )≦θ2≦180×2/(5 ·Pn ) or 0<θ1<180/(7 ·Pn ) and 180/(7 ·Pn )≦θ2≦180×2/(7 ·Pn ) where a pole pair number is Pn.