Patent ID: 7898137
Filing Date: 2011-03-01
Classification: H02K

Abstract:
1. A permanent magnet having a D-shaped cross section including a generally arcuate top surface, a flat bottom surface, and side surfaces, said generally arcuate top surface including a central region with an apex and transversely opposed end regions, wherein provided that a plurality of permanent magnets are circumferentially arranged so that a phantom great circle circumscribes the apexes on the arcuate top surfaces of the magnets, the central region of the magnet top surface delineates a contour which is entirely coincident with an arc of a phantom small circle off-centered from said great circle and having a smaller diameter than said great circle, said small circle and the magnet side surface intersect each other, and each of the transversely opposed end regions of the magnet top surface is positioned outside the intersection between said small circle and the magnet side surface and inside said great circle.