Dynamoelectric machine with a laminated pole permanent magnet rotor

Claim 1

A dynamoelectric machine comprising: a stator assembly; a rotor mounted for rotation within said stator assembly; said rotor comprising a laminated core having a central portion including a plurality of non-magnetic structural laminations and a plurality of magnetic laminations interspersed among said non-magnetic structural laminations, and said core having two end portions each having a plurality of said non-magnetic structural laminations positioned adjacent to each other; a plurality of permanent magnets extending longitudinally within said core, each of said permanent magnets having pole faces oriented in planes which are substantially perpendicular to the circumferential direction; a plurality of magnetic pole pieces extending longitudinally within said core, each of said magnetic pole pieces lying adjacent to one of said pole faces of each of said permanent magnets and extending circumferentially from the associated major surface to an edge of adjacent ones of said magnetic laminations to produce a plurality of magnetic flux paths circumferentially disposed about the periphery of said core, wherein the cross-sectional area of each of said pole pieces in a plane perpendicular to the rotor axis is substantially constant within the central portion of said core and decreases as said pole pieces extend from said central portion into the end portions of said core; and means for securing said laminations into a unit.