Patent ID: 8304950

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, a trough portion that curves radially inward being formed on a portion of each of said yoke portions between circumferentially adjacent claw-shaped magnetic pole portions, and said pole core being prepared such that tip end portions of said claw-shaped magnetic pole portions overlap with said yoke portions axially, and being fixed to a rotating shaft that is inserted through a central axial position of said boss portion; and a field coil 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 an outer circumference of said rotor so as to have a predetermined air gap interposed, said dynamoelectric machine comprising: a magnetic guidance member that is made of a magnetic material and is disposed so as to span said trough portion by being connected to each of consecutive yoke portions at locations above a bottom of said trough; and a permanent magnet that is disposed on said magnetic guidance member so as to face an inner circumferential surface near a tip end of said claw-shaped magnetic pole portions so as to have a predetermined clearance, and that is magnetically oriented in a reverse direction to an orientation of a magnetic field produced by said field coil.