Patent ID: 8714948

Claim:
A permanent magnet motor comprising: a stator; and a rotor, the stator including: a stator core, which is a layered cylindrical core, including a plurality of slots positioned in a circumferential direction; magnetic pole teeth each formed between adjacent slots among the plurality of slots; and cut surfaces formed in circumferential end portions on an inner peripheral surface of each of the magnetic pole teeth; and coils of concentrated winding that are wound directly around the magnetic pole teeth, the rotor, which faces an inner peripheral side of the magnetic pole teeth via an air gap, including: a rotor core including magnet retaining holes formed in places corresponding to respective sides of an approximate regular polygon whose center is a center of an axis; and pairs of first slits, each pair extending from circumferential end portions of each of the magnetic retaining holes along the circumferential direction, and being oriented toward a magnetic pole center; and permanent magnets that are embedded in the magnet retaining holes, and are magnetized so that N poles and S poles are arranged alternately, wherein each of the circumferential end portions of each of the magnet retaining holes has a continuous space in which at least two radially outward facing surfaces and a radially inward facing surface of each of the permanent magnets are exposed so as to be kept from being in contact with the rotor core, and wherein a length D of each of the permanent magnets in a longitudinal direction is no less than a width A between the circumferential end portions on the inner peripheral surface of each of the magnetic pole teeth in the circumferential direction, a distance C between tip portions of each pair of first slits is smaller than the width A between the circumferential end portions on the inner peripheral surface of each of the magnetic pole teeth in the circumferential direction, and thereby the cut surfaces face the pairs of first slits.