Patent ID: 7932658

Claim:
An electric machine comprising: a stator; a rotor positioned adjacent the stator and configured to rotate with respect to the stator, the rotor including a plurality of laminations having a circular outside diameter and stacked in a stackwise direction, each lamination including a plurality of continuous arcuate slots positioned inward of the outside diameter, each continuous arcuate slot including an inner portion spaced a first distance from the outside diameter, a first end portion disposed a second distance from the outside diameter, a second end portion disposed the second distance from the outside diameter, the second distance being smaller than the first distance, a first arcuate protrusion configured to narrow the continuous arcuate slot adjacent the first end portion, and a second arcuate protrusion configured to narrow the continuous arcuate slot adjacent the second end portion; and a plurality of permanent magnets, each magnet disposed in one of the continuous arcuate slots completely between the first arcuate protrusion and the second arcuate protrusion.