Patent ID: 9350204
Filing Date: 2016-05-24
CPC Classification: H02K

Claim Text:
1. A permanent magnet rotating electrical machine, comprising: a rotor having a rotor core and a plurality of magnetic poles formed of permanent magnets provided to the rotor core; and a stator having a plurality of teeth opposing the plurality of magnetic poles, a stator core provided with slots in which to store an armature winding wire wound around the teeth, and supplemental grooves provided to the teeth in portions opposing the rotor in an axial direction of the stator core, the permanent magnet rotating electrical machine being characterized in that: the supplemental grooves are provided to the stator so as not to be formed in an axial end portion of the stator core; and let P be the number of the magnetic poles (the number of poles) and S be the number of the slots (the number of slots), then a relation, 0.75<S/P<1.5, is established, and let Lc be an axial length of the stator core and Ld be a length of a portion in which the supplemental grooves are provided in the axial direction of the stator core, then Lc and Ld satisfy a relational expression, 0.4≦Ld/Lc≦0.6, wherein a phase of a cogging torque S'th-order component generated in the portion in which the supplemental grooves are provided and a phase of a cogging torque S'th-order component generated in the portion in which no supplemental grooves are provided are inverted from each other.