Electromechanical actuator

A stator for a permanent magnet motor comprising, in combination:

• a pair of end bells in spaced apposition along an axis;
• a set of ferromagnetic inner pole pieces secured at their ends to said bells to extend therebetween parallel to said axis, said inner pole pieces having pairs of flat outer surfaces, intersecting at dihedral angles having vertices parallel to said axis, and concave inner curved surfaces comprising peripherally spaced portions of a first cylinder circular on said axis defined by angles less than the supplements of said dihedral angles;
• flat permanent magnets having inner poles which lie in inner surfaces secured to the flat outer surfaces of said inner pole pieces, said magnets further having outer poles lying in outer surfaces which compose the faces of a prism of rectangular polygonal cross section normal to said axis, said outer faces terminating short of the centers of said faces;
• and a set of ferromagnetic outer pole pieces having inner flat surfaces secured to the outer flat surfaces of said magnets, each of said outer pole pieces engaging one flat outer surface of each of two peripherally adjacent magnets to complete a ferromagnetic path from a first inner pole piece through a first magnet, an outer pole piece, and a second magnet to a second inner pole piece, by bridging a gap between said first and second magnets at surfaces of opposite polarity.