Patent ID: 8148864

Claim:
A dynamoelectric machine comprising: a rotor comprising: a pole core comprising: a boss portion; a pair of yoke portions that are disposed so as to extend radially outward from two axial end edge portions of said boss portion; and a plurality of claw-shaped magnetic pole portions that are disposed so as to extend in an axial direction alternately from each of said pair of yoke portions, and that are arranged circumferentially so as to intermesh with each other, said pole core being fixed to a shaft that is inserted through a central axial position of said boss portion; a resin bobbin comprising: a drum portion that is mounted so as to be fitted over said boss portion; and a pair of flange portions that extend radially outward from two axial end portions of said drum portion along inner wall surfaces of said pair of yoke portions; and a field coil that is wound onto said bobbin, and that is housed inside a space that is surrounded by said boss portion, said pair of yoke portions, and said plurality of claw-shaped magnetic pole portions; and a stator that is disposed so as to surround said rotor with a predetermined air gap interposed, wherein: a magnet housing portion is disposed integrally on an outer circumferential portion of at least one flange portion of said pair of flange portions of said bobbin so as to extend axially outward and so as to extend near a portion of said yoke portions that faces an inner circumferential surface near a tip end of said claw-shaped magnetic pole portions; a permanent magnet is housed and held in said magnet housing portion, is disposed so as to face said inner circumferential surface near said tip end of said claw-shaped magnetic pole portions, and is magnetically oriented in a reverse direction to a direction of a magnetic field that said field coil produces; trough portions are formed so as to curve concavely radially inward at portions of said yoke portions between respective circumferentially adjacent claw-shaped magnetic pole portions; a magnetic body is housed and held inside said magnet housing portion together with said permanent magnet so as to be positioned radially inside said permanent magnet; and said magnet housing portion is held by said yoke portions by fitting together with said trough portions.