Patent ID: 8237323

Claim:
A rotor for an alternator in a motor vehicle, comprising: a) a shaft ( 14 ) having knurls ( 57 ) which extend from its outer surface; b) an intermediate sleeve ( 58 ) which i) is made of ferromagnetic material; ii) has been force-fitted onto the shaft ( 14 ); iii) contains an inner surface that frictionally engages force-fit onto the knurls ( 57 ) during force-fitting to prevent relative rotational movement between said intermediate sleeve and the shaft; iv) is fixed against relative rotation with respect to the shaft ( 14 ); and v) has been machined to have an outer surface ( 60 ) which is cylindrical and generally concentric with said shaft ( 14 ); and c) a left pole piece ( 20 ) and a right pole piece ( 22 ) that are arranged axially on each side of an annular core that is coaxial with the shaft, said annular core having a coil that extends radially around it, both of which contain bores ( 38 ) which 1) have been machined to have an inner surface which is cylindrical, concentric with and of generally the same diameter as said outer surface ( 60 ); and 2) surround and mate with the machined outer surface ( 60 ) so that said left pole piece ( 20 ) and said right pole piece ( 22 ) are arranged axially on each side of said annular core; said intermediate sleeve ( 58 ) being situated radially between said shaft and said inner surfaces of said left pole piece and said right pole piece after they are mounted on said intermediate sleeve.