| 摘要 |
Permanent magnets 52 a 1, 52 a 2 are inserted into magnet insert holes 51 a 1, 51 a 4 formed in a main magnetic pole 50 A of a rotor 50 . An outer circumferential surface of the rotor includes a first outer circumferential surface portion 50 a which intersects with a d-axis and second outer circumferential surface portions 50 da, 50 ab which intersect with a q-axis. A radius R 2 of curvature of the second outer circumferential surface portions 50 da, 50 ab is larger than a radius of curvature of the first outer circumferential surface portions 50 a. Recesses 50 a 1, 50 a 2 are formed in the second outer circumferential surface portions 50 da, 50 ab and in a position to face end walls 51 a 2, 51 a 5 of the magnet insert holes 51 a 1, 51 a 4 which are adjacent to the outer circumferential surface of the rotor. It is constructed such that [(74/P)°<=theta<=(86/P)°] and [(16/P)°<=alpha<=(48/P)°], where theta is a mechanical angle of the first outer circumferential surface portion 50 a, P is the number of pairs of poles of the rotor 50 , and alpha is a mechanical angle of the recesses 50 a 1, 50 a 2.
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