Patent ID: 7528519

Claim:
A permanent magnet rotary motor, comprising: a rotor including a rotary shaft, a rotor core fixed to the rotary shaft, and a plurality of permanent-magnet magnetic pole sections composed of a plurality of permanent magnets attached to the rotor core; a stator core including an annular yoke, N wherein N is an even number of 4 or more pole columns disposed inside the annular yoke at intervals in a circumferential direction of the yoke with one end of the pole column being connected to the yoke and the other end thereof being positioned on an inner side than the one end in a radial direction of the yoke, N magnetic pole surface constituent sections respectively formed on the other ends of the N pole columns, each having an inner side magnetic pole surface facing the rotor, and N connecting portions connecting two adjacent sections among the magnetic pole surface constituent sections, and formed with one or more through-holes penetrating therethrough in the radial direction; and N exciting winding sections, respectively mounted onto N pole columns of the stator core, the N connecting portions including N/2 first type connecting portions and N/2 second type connecting portions, the first and second type connecting portions being alternately disposed in a circumferential direction of the rotor, wherein when an angle formed between two virtual lines respectively connecting a center of the rotary shaft and both ends, mutually opposed in the circumferential direction, of the first type connecting portion is defined as a first angle θ 1 and an angle formed between two virtual lines respectively connecting the center of the rotary shaft and both ends, mutually opposed in the circumferential direction, of the second type connecting portion is defined as a second angle θ 2 , a relationship between the first angle θ 1 and the second angle θ 2 is θ 1 >θ 2 ; wherein one through-hole is formed in the first type connecting portion, extending from a center position of the first type connecting portion as viewed in an axial direction of the rotary shaft toward both sides in the axial direction; wherein one through-hole is formed in the second type connecting portion, extending from a center position of the second type connecting portion as viewed in the axial direction toward both sides in the axial direction; wherein the length of the through-hole formed in the first type connecting portion is longer than the length of the through-hole formed in the second type connecting portion in the circumferential direction; and wherein the length of the through-hole formed in the first type connecting portion is shorter than the length of the through-hole formed in the second type connecting portion in the axial direction.