Permanent magnet-embedded electric motor

An interior permanent magnet motor, comprising:

• a rotator comprising a rotator core;
• and
• a stator provided so as to surround the rotator,
• wherein the rotator core comprises:
• a plurality of magnet accommodating holes formed as many as the number of poles along a circumferential direction;
• and
• a plurality of permanent magnets accommodated in the plurality of magnet accommodating holes,
• wherein the magnet accommodating hole is formed into a recessed shape when viewed along a rotation axis direction of the rotator, and is arranged so that a recessed side is directed toward an outer side of the rotator,
• wherein the magnet accommodating hole is formed so as to have a symmetrical shape with respect to a center line of a magnetic pole when viewed along the rotation axis direction of the rotator, and is formed into an integral structure without being divided in the same pole,
• wherein a thickness in a short-side direction of the magnet accommodating hole is minimum at a center portion of the magnetic pole, and is gradually increased toward a radially outer side of the rotator core,
• wherein at least a thickness in a short-side direction of the permanent magnet at the center portion of the magnetic pole is equal to the thickness in the short-side direction of the corresponding magnet accommodating hole at the center portion of the magnetic pole,
• wherein the magnet accommodating hole and the permanent magnet are formed so that, when viewed along the rotation axis direction of the rotator and when a radius of an arc on a center side of the rotator core and a radius of an arc on an outer peripheral side of the rotator core in arcs defining the magnet accommodating hole are represented by R1 and R2, respectively, and a radius of an arc on an outer peripheral side of the rotator core in arcs defining the permanent magnet is represented by R3, a relationship of R1>R3>R2 is satisfied, and
• wherein a space portion is formed between the magnet accommodating hole and each of both end portions of the corresponding permanent magnet, and the space portion is gradually increased toward the end portion of the corresponding permanent magnet.