Patent ID: 8018110

Claim:
An internal permanent magnet machine comprising: a stator assembly comprising a stator core, the stator core comprising a plurality of stator teeth, the stator assembly is further configured with stator windings to generate a stator magnetic field when excited with alternating currents and extends along a longitudinal axis with an inner surface defining a cavity; and a rotor assembly comprising a rotor core, the rotor assembly disposed inside said cavity and configured to rotate about the longitudinal axis, wherein the rotor assembly comprises: a shaft comprising a plurality of protrusions alternately arranged relative to a plurality of bottom structures; a plurality of stacks of laminations, the stacks disposed radially outward on the protrusions and dovetailed circumferentially around the shaft; a plurality of permanent magnets disposed between the stacks and are configured to generate a magnetic field, which magnetic field interacts with the stator magnetic field to produce a torque; and a plurality of bottom wedges substantially distinct from the shaft and disposed radially outward on the bottom structures of the shaft and configured to hold the plurality of stacks to the shaft.