Patent ID: 7053515

Claim:
A rotor for a rotary electric machine, comprising: a pair of pole cores in each of which a plurality of claw-shaped magnetic poles having a tapered shape are formed at a uniform angular pitch in a circumferential direction on an outer circumferential edge portion of a cylindrical base portion such that a direction of taper of said claw-shaped magnetic poles is aligned in an axial direction, said pair of pole cores being constructed by placing end surfaces of said base portions in contact with each other such that said claw-shaped magnetic poles intermesh; a bobbin constructed into an annular shape having an angular C-shaped cross section by disposing first and second flange portions so as to extend radially outward from two axial end portions of a cylindrical drum portion, said bobbin being mounted to said base portions so as to be held between root portions of said claw-shaped magnetic poles of said pair of pole cores; and a rotor coil having a coil field constructed by winding a coil wire having a circular cross section onto an outer circumference of said drum portion of said bobbin in multiple layers so as to make columns in each of said layers equal in number in an axial direction, wherein: odd numbered layers of said coil field are constructed such that said coil wire is wound for approximately one turn around said drum portion in contact with an inner peripheral wall surface of said first flange portion, then wound into a plurality of columns in an axial direction such that said columns of said coil wire contact each other, and said coil wire in a final column forms a gap S relative to an inner peripheral wall surface of said second flange portion; even numbered layers of said coil field are constructed such that said coil wire is wound for approximately one turn around said drum portion in contact with an inner peripheral wall surface of said second flange portion, then wound into a plurality of columns in an axial direction such that said columns of said coil wire contact each other, and said coil wire in a final column forms said gap S relative to an inner peripheral wall surface of said first flange portion; said gap S satisfies an expression D/4≦S≦D/2 relative to a diameter D of said coil wire; and, said coil field is constructed such that crossover points formed by said coil wire in radially-adjacent layers do not overlap in a radial direction.