Patent ID: 7358637
Filing Date: 2008-04-15
Classification: H02K

Abstract:
1. A method of compressing lamination stacks for a permanent magnet rotor, comprising the steps of: a) providing a plurality of stages of lamination stacks and magnets on a rotor shaft to form an assembly; b) positioning a spacer between each of the lamination stacks of each of the plurality of stages such that the spacers and lamination stacks abut each other; and c) fitting a disc-shaped retainer plate at each end of the assembly for axially restraining the lamination stacks and spacers, each retainer plate having a circular groove facing away from the lamination stacks and being radially inward of the outer radial edge of the disc-shaped retainer plates, wherein the grooves allow centrifugal force to deflect the outer radial edges of the retainer plates inward toward the lamination stacks, wherein the spacers are milled to a size that is slightly wider than an axial gap between the lamination stacks of each stage.