Interior permanent magnet synchronous motor

An interior permanent magnet synchronous motor comprising:

• a stator including a stator core provided with a plurality of magnetic pole sections having windings of at least one phase wound thereon;
• a rotor of which the number of pole pairs is p (p:
• a positive integer of 1 or more);
• said rotor including a shaft and a rotor core fixed on said shaft;
• said rotor core having a plurality of permanent magnets incorporated therein in a manner to be spaced from each other at intervals in a peripheral direction thereof;
• said permanent magnets each constituting a permanent magnet magnetic pole section formed on an outer periphery of said rotor core;
• said rotor being formed with a plurality of magnetic silent pole sections so as to interpose said permanent magnet magnetic pole section therebetween;
• said rotor core including an outer peripheral surface sections each positioned between each adjacent two of said magnetic silent pole sections;
• said outer peripheral surface sections of said rotor core each having a contour formed into an arcuate or elliptic configuration;
• and
• said arcuate or elliptic configuration being so determined that said outer peripheral surface section of said rotor core and said magnetic pole surface of each of said magnetic poles of said stator core cooperate with each other to define therebetween a gap of a size δd approaching to a value determined by the following expression:
• δd=δd0/cos(pθd)
• wherein δd0 is a size of said gap which is determined along a virtual central line defined so as to extend through centers of two virtual lines extending from a center of said shaft through both ends of each of said outer peripheral surface sections defined in a peripheral direction thereof and θd is an angle between said virtual central line and each of said virtual lines.

An interior permanent magnet synchronous motor comprising:

• a stator including a stator core provided with a plurality of magnetic pole sections having windings wound thereon;
• a rotor of which the number of pole pairs is p, wherein p is a positive integer of 1 or more;
• said rotor including a shaft and a rotor core fixed on said shaft;
• said rotor core having a plurality of permanent magnets incorporated therein in a manner to be spaced from each other at intervals in a peripheral direction thereof;
• said permanent magnets each constituting a permanent magnet magnetic pole section formed on an outer periphery of said rotor core;
• said rotor being formed with a plurality of magnetic salient pole sections so as to interpose said permanent magnet magnetic pole sections therebetween;
• said rotor core including outer peripheral surface sections each positioned between each adjacent two of said magnetic salient pole sections;
• and
• said rotor being configured so that an angle φp between two virtual lines extending from a center of said shaft through both ends of each of said outer peripheral surface sections defined in a peripheral direction thereof and an open angle α of the magnetic salient pole sections which is defined as an angle between two virtual lines extending through the center of said shaft and both ends of each of said magnetic salient pole sections in a peripheral direction thereof are defined so as to satisfy the following expression:
• (180/p+α−φp)/τs≈2n−1
• wherein τs is a slot pitch of said stator core, n is a natural number, α>0, φp >0, and α+φp≦180/p.