Patent ID: 8179015

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 fixed to a shaft that is inserted through a central axial position of said boss portion; and a field coil that is wound onto a bobbin that is mounted to said boss portion, 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; a stator that is disposed so as to surround an outer circumference of said rotor; and a permanent magnet that is disposed in said trough portion so as to face an inner circumferential surface near a tip end of said claw-shaped magnetic pole portions, said dynamoelectric machine further comprising: an interfitting groove that is disposed in a bottom portion of said trough portion so as to have a groove direction that is axial and so as to extend axially outward from axially inside; a rotation arresting portion housing recess portion that is recessed into an axially inner opening edge portion of said interfitting groove on said yoke portions; a magnet holding seat that is disposed in said trough portion by being fitted into said interfitting groove such that radial movement is restricted, and that holds said permanent magnet; and a rotation arresting portion that is disposed so as to project axially outward from a flange portion of said bobbin, wherein said rotation arresting portion is housed inside a space that is constituted by said rotation arresting portion housing recess portion and said magnet holding seat such that rotation of said bobbin around said shaft is restricted.