Patent ID: 7768172

Claim:
A permanent magnet type electric rotary machine comprising: a stator including a stator core having teeth and slots between adjacent teeth, and a concentrated winding as an armature winding installed in each of the slots so as to surround each of the teeth; and a rotor provided with permanent magnets as magnet poles installed in a plurality of permanent magnet insertion holes provided in a rotor core respectively, the rotor being rotatably supported inside the stator keeping a gap between the rotor core and the stator core by a rotating shaft, wherein defining that a magnetic flux axis of each of the permanent magnets is a d-axis, and an axis 90° apart in electrical angle from the d-axis is a q-axis, respective install positions of the permanent magnets in the rotor core are set between adjacent q-axes, wherein a pole core portion between each of the permanent magnets and an outer surface of the rotor core is provided with a plurality of pole slits, wherein the region of the pole core portion is defined by concave portions provided on q-axes to be interpolars on both sides of the pole core portion, and thereby configured that a gap (g2) between the outer surface on the q-axis of the rotor core and an inner surface of the stator core is larger than a gap (g1) between the outer surface on the d-axis of the pole core portion and the inner surface of the stator, so that magnetic fluxes from the permanent magnet pass through the pole core portion concentrately, wherein the outer surface like an arc-shape of the pole core portion is formed asymmetrically with respect to the d-axis by making circumferential-direction lengths of the concave portions on both sides of the pole core portion different from each other; and wherein each of the concave portion is formed in the axial direction of the rotor core, with at least one stepped v-shape skew structure in view of the circumferential direction of the rotor core, so that the pole core portion has at least one stepped v-shape skew structure.