Patent ID: 8207642

Claim:
Power conversion apparatus comprising a shaft, a stator, and a rotor, the shaft, stator, and rotor being coaxially disposed with the rotor mounted on the shaft, the stator including at least one winding, and the rotor including a plurality of permanent magnets disposed proximate to the stator, separated from the stator by a predetermined gap distance, such that relative motion of the rotor and stator causes magnetic flux from the magnets to magnetically interact with the stator winding, wherein: the shaft has a diameter and includes a tapered portion disposed between the ends of the shaft at a predetermined position relative to the stator, the diameter of the tapered portion varying in accordance with a predetermined taper from a minimum diameter greater than the diameter of the shaft to a maximum diameter greater than the diameter of the shaft; the rotor includes a central through-bore having a predetermined taper corresponding to that of the tapered portion of the shaft; and the shaft is journaled through the rotor tapered bore, such that shaft tapered portion is received in the rotor bore, cooperation of the tapered rotor bore and tapered shaft portion positioning the rotor with respect to the shaft and the stator.