Rotor with arcuate magnets

Abstract

A spoked rotor is rotatable about an axis. The rotor includes a core. The core includes a plurality of pole segments arranged arcuately about the axis. The rotor includes a plurality of arcuately arranged magnets alternating arcuately with the pole segments, such that each of the magnets is at least in part interposed between a pair of adjacent pole segments. Each of the magnets includes a curved section extending arcuately between radially inner and outer curved section ends. An effective rotor pole location is defined on each of the pole segments. Each of the pole segments has an end opposite the effective rotor pole location. A center point is defined at the pole segment end. Each of the effective rotor pole locations is arcuately offset from a corresponding one of the center points by between about five tenths (0.5) rotor poles and about two (2.0) rotor poles.

What is claimed is: 
     
         1 . A spoked rotor rotatable about an axis, said rotor comprising:
 a core including a plurality of pole segments arranged arcuately about the axis; and   a plurality of arcuately arranged magnets alternating arcuately with said pole segments, such that each of the magnets is at least in part interposed between a pair of adjacent pole segments,   each of said magnets including a curved section extending arcuately between radially inner and outer ends.   
     
     
         2 . The rotor as claimed in  claim 1 ,
 said curved section presenting opposite axially extending curved faces, each extending arcuately between the inner and outer ends.   
     
     
         3 . The rotor as claimed in  claim 1 ,
 said curved section presenting opposite axially extending curved faces, each having a constant radius of curvature between the inner and outer ends, with spacing between the curved faces being constant the full length of the curved section.   
     
     
         4 . The rotor as claimed in  claim 1 ,
 said curved section presenting opposite axially extending curved faces, each extending arcuately between the inner and outer ends,   one of said curved faces facing generally radially inward,   another of said curved faces facing generally radially outward.   
     
     
         5 . The rotor as claimed in  claim 1 ,
 each of said magnets further including a straight section adjacent the curved section thereof.   
     
     
         6 . The rotor as claimed in  claim 5 ,
 said curved section presenting opposite axially extending curved faces, each extending arcuately between the inner and outer ends,   said straight section presenting opposite axially extending straight faces, each extending from a corresponding one of the curved faces at the outer end.   
     
     
         7 . The rotor as claimed in  claim 6 ,
 each of said straight faces extending tangentially from the corresponding one of the curved faces at the outer end.   
     
     
         8 . The rotor as claimed in  claim 5 ,
 said curved section presenting opposite axially extending curved faces, each extending arcuately between the inner and outer ends, with spacing between the curved faces being constant the full length of the curved section,   said straight section presenting opposite, parallel, axially extending straight faces.   
     
     
         9 . The rotor as claimed in  claim 5 ,
 said curved section extending along a curved section centerline and having a curved section length defined along the curved section centerline,   said straight section extending along a straight section centerline and having a straight section length defined along the straight section centerline,   said magnet having a total length equal to the sum of the curved section length and the straight section length,   said curved section length being at least 50% of the total length.   
     
     
         10 . The rotor as claimed in  claim 9 ,
 said curved section length being between about  60 % and about 90% of the total length.   
     
     
         11 . The rotor as claimed in  claim 5 ,
 said straight section presenting a non-rectangular axial face.   
     
     
         12 . The rotor as claimed in  claim 1 ,
 each of said pairs of adjacent pole segments defining a slot therebetween,   each of said slots including a magnet-receiving portion and a gap portion,   said gap portion being at least substantially disposed radially outwardly of said magnet-receiving portion,   each of said magnets being at least in part received within a corresponding one of said magnet-receiving portions, with each of the corresponding gap portions being devoid of the magnet.   
     
     
         13 . The rotor as claimed in  claim 1 ,
 said curved section having an arc length between about 45 degrees and about 95 degrees.   
     
     
         14 . The rotor as claimed in  claim 13 ,
 said arc length being between about 60 degrees and about 80 degrees.   
     
     
         15 . A rotor rotatable about an axis, said rotor comprising:
 a core including a plurality of pole segments arranged arcuately about the axis; and   a plurality of arcuately arranged magnets alternating arcuately with said pole segments, such that each of the magnets is at least in part interposed between a pair of adjacent pole segments,   wherein an effective rotor pole location is defined on each of said pole segments,   each of said pole segments having an end opposite the effective rotor pole location,   wherein a center point is defined at said end,   each of said effective rotor pole locations being arcuately offset from a corresponding one of the center points by between about 0.5 rotor poles and about 2.0 rotor poles.   
     
     
         16 . The rotor of  claim 15 ,
 each of said rotor poles being arcuately offset from the corresponding ones of the center points by between about 1.25 rotor poles and about 1.5 rotor poles.   
     
     
         17 . The rotor of  claim 15 ,
 said rotor core defining a radially outermost circumferential margin,   each of said center points being spaced from said margin by a radial distance,   each of said magnets extending along a magnet centerline having a total length,   each of said total magnet lengths being at least 10% greater than a corresponding one of said radial distances.   
     
     
         18 . The rotor of  claim 15 ,
 each of said magnets including a curved section and a straight section adjacent the curved section.   
     
     
         19 . The rotor of  claim 18 ,
 said curved section extending along a curved section centerline and having a curved section length defined along the curved section centerline,   said straight section extending along a straight section centerline and having a straight section length defined along the straight section centerline,   said magnet having a total length equal to the sum of the curved section length and the straight section length,   said curved section length being at least 50% of the total length.   
     
     
         20 . The rotor of  claim 19 ,
 said curved section extending arcuately between radially inner and outer ends,   said curved section having an arc length between about 45 degrees and about 95 degrees.