Rotating electrical machine

Abstract

A rotating electrical machine includes a supporting member, a stator core, a winding set, a shaft, a rotor, a magnetic generator, and a magnetic detector. The stator core has a ring-shaped yoke held inside the supporting member and tooth portions projecting from the yoke in a radial inward direction of the yoke. The winding set is wound on the tooth portions. The shaft extends through the stator core and is rotatably supported by the supporting member. The rotor is located in the stator core and rotates with the shaft. The magnetic generator is located at an end of the shaft. The magnetic detector outputs a signal indicative of a change in magnetic flux density created by the magnetic generator. The number of the tooth portions for every magnetic pole pair in the rotor is even.

What is claimed is: 
     
         1 . A rotating electrical machine comprising:
 a supporting member;   a stator core including a ring-shaped yoke and tooth portions, the yoke being held in the supporting member, the tooth portions projecting from the yoke in a radial inward direction of the yoke;   a winding set wound on the tooth portions;   a shaft extending through the stator core and rotatably supported by the supporting member;   a rotor located in the stator core and configured to rotate with the shaft;   a magnetic generator located at an end of the shaft; and   a magnetic detector configured to output a signal indicative of a change in magnetic flux density created by the magnetic generator, wherein   the number of the tooth portions for every magnetic pole pair in the rotor is even.   
     
     
         2 . The rotating electrical machine according to  claim 1 , wherein
 the winding set includes three phase windings, and   each of the three phase windings is wound on the tooth portions at intervals of an electrical angle equal to or greater than {(2k+1)×n/3k}, where k is the number of the tooth portions for every magnetic pole and every phase.   
     
     
         3 . The rotating electrical machine according to  claim 2 , wherein the number of the tooth portions for every magnetic pole in the rotor is equal to or greater than 3k−1. 
     
     
         4 . The rotating electrical machine according to  claim 1 , wherein the yoke and the tooth portions are formed as a single piece. 
     
     
         5 . The rotating electrical machine according to  claim 1 , wherein
 the magnetic pole pair includes a first magnetic pole and a second magnetic pole, and   a magnetic reluctance of the first magnetic pole is smaller than a magnetic reluctance of the second magnetic pole.   
     
     
         6 . The rotating electrical machine according to  claim 5 , wherein
 the first magnetic pole has a first length in a circumferential direction of the rotor,   the second magnetic pole has a second length in the circumferential direction, and   the first direction is not greater than the second direction.   
     
     
         7 . The rotating electrical machine according to  claim 1 , wherein
 the magnetic detector has a magnetoresistive element located in an axis direction of the magnetic generator.   
     
     
         8 . The rotating electrical machine according to  claim 1 , wherein
 the magnetic detector has a Hall element located in a radial outward direction of the magnetic generator.   
     
     
         9 . The rotating electrical machine according to  claim 1 , further comprising:
 a processor configured to calculate a relative rotation angle of the rotor with respect to the stator core based on the signal outputted from the magnetic detector, and   an energization controller configured to control an electric current flowing through the winding set based on the relative rotation angle.