Rotating electric machine having rotor embedded-permanent-magnets with inner-end magnetic gaps and outer-end magnetic gaps, and electric car using the same electric machine

Abstract

A permanent magnet rotating electric machine comprises a stator having stator windings wound round a stator iron core and a permanent magnet rotor having a plurality of inserted permanent magnets in which the polarity is alternately arranged in the peripheral direction in the rotor iron core. The rotor iron core of the permanent magnets is composed of magnetic pole pieces, auxiliary magnetic poles, and a stator yoke, and furthermore has concavities formed on the air gap face of the magnetic pole pieces of the rotor iron core of the permanent magnets, gently tilting from the central part of the magnetic poles to the end thereof. In a permanent magnet rotating electric machine, effects of iron loss are reduced, and an electric car using highly efficient permanent magnet rotating electric machine are realized.

1. A permanent magnet electric rotating machine, comprising:
 a stator; 
 a rotor having a rotor iron core and being arranged opposite said stator with a rotation air gap therebetween; 
 a plurality of magnetic poles in said rotor iron core and arranged in a peripheral direction of said rotor in which polarity is alternately arranged; 
 a plurality of auxiliary magnetic pole portions arranged in the peripheral direction between said magnetic poles; and 
 bridge portions which connect magnetic pole piece portions formed between said magnetic poles and a surface of said rotor with said auxiliary magnetic pole portions, each of said magnetic pole piece portions formed between two permanent magnets of each of said magnetic poles and an outer surface of the rotor, wherein 
 said two permanent magnets of each said magnetic pole has two permanent magnets ofhave common polarity and are in a V-shape arrangement opening towards said stator, 
 a core portion of said rotor iron core and a first magnetic gap are provided between each of the inner ends of said two permanent magnets, said core portion being provided to connect said magnetic pole piece portions with said rotor iron core radically radially inward of said magnetic poles, and 
 second magnetic gaps are provided between outer ends of said two permanent magnets and said bridge portions. 
 
     
     
       2. A permanent magnet rotating electric machine according to  claim 1  wherein
 said rotor iron is further composed of concavities formed on an air gap face of said magnetic pole pieces. 
 
     
     
       3. A permanent magnet rotating electric machine according to  claim 2 , wherein:
 a change in a length of the rotation air gap at a central part of said magnetic poles at a position of said concavities is smaller than a change in the length of the rotation air gap at an end of said magnetic poles. 
 
     
     
       4. A permanent magnet rotating electric machine according to  claim 2 , wherein:
 a length of the rotation air gap of said auxiliary magnetic pole portions is smaller than the length of the rotation air gap of said magnetic pole pieces. 
 
     
     
       5. A permanent magnet rotating electric machine according to  claim 2 , wherein:
 said concavities are within an electrical angle range of 20° to 30° from said magnetic pole center where there are two slots of said stator iron core per pole and per phase. 
 
     
     
       6. A permanent magnet rotating electric machine according to  claim 2 , wherein:
 said concavities are within an electrical angle range of 15° to 45° from said magnetic pole center where there is one slot of said stator iron core per pole and per phase. 
 
     
     
       7. An electric car comprising a permanent magnet rotating electric machine, wheels driven by said permanent magnet rotating electric machine, and control means for controlling drive torque outputted by said permanent magnet rotating electric machine, wherein:
 said permanent magnet rotating electric machine is composed of a stator; 
 a rotor having a rotor iron core and being arranged opposite said stator with a rotation air gap therebetween; 
 a plurality of magnetic poles in said rotor iron core and arranged in a peripheral direction of said rotor in which polarity is alternately arranged; 
 a plurality of auxiliary magnetic pole portions arranged in the peripheral direction between said magnetic poles; and 
 bridge portions which connect magnetic pole piece portions formed between said magnetic poles and a surface of said rotor with said auxiliary magnetic pole portions, each of said magnetic pole piece portions formed between two permanent magnets of each of said magnetic poles and an outer surface of the rotor, wherein 
 said two permanent magnets of each said magnetic pole has two permanent magnets ofhave common polarity and are in a V-shape arrangement opening towards said stator, 
 a core portion of said rotor iron core and a first magnetic gap are provided between each of the inner ends of said two permanent magnets, said core portion being provided to connect said magnetic pole piece portions with said rotor iron core radially inward of inside said magnetic poles, and 
 second magnetic gaps are provided between outer ends of said two permanent magnets and said bridge portions. 
 
     
     
       8. An electric car according to  claim 7 , wherein
 said rotor iron core is further composed of 
 magnetic pole pieces positioned on an air gap face of said permanent magnets for forming a magnetic path of said permanent magnets, 
 auxiliary magnetic poles projected up to said air gap face of said permanent magnets for producing reluctant torque, and 
 a stator yoke positioned on a reversed air gap face of said permanent magnets for forming a magnetic path of said auxiliary magnetic poles and said permanent magnets, and further includes concavities formed on an air gap face of said magnetic pole pieces. 
 
     
     
       9. An electric car according to  claim 8 , wherein:
 said concavities are within an electrical angle range of 20° to 30° from said magnetic pole center where there are two slots of said stator iron core per pole and per phase. 
 
     
     
       10. An electric car according to  claim 8 , wherein:
 said concavities are within an electrical angle range of 15° to 45° from said magnetic pole center where there is one slot of said stator iron core per pole and per phase.