A stator core of an AC generator for vehicles is laminated by helically winding a band-like steel plate and is formed to be approximately cylindrical. A yoke of the stator core is held between a pair of frames. An axial extending groove-like recess is provided in the outer peripheral portion of the stator...http://www.google.ca/patents/US6337530?utm_source=gb-gplus-sharePatent US6337530 - AC generator for vehicle with helical stator having bolt recesses on outer cylindrical surface
