Single-phased angular electromagnetic actuator

Claim 1

An angular single-phased electromagnetic actuator comprising: a stator structure having two stator parts provided opposite each side of a thin magnetized portion of an angularly movable member, each of said stator parts made of a material having a very high magnetic permeability, at least one of the stator parts having 2N+1 magnetic poles where N is an integer, at least one of said magnetic, poles being energized by an electrical coil, a finite portion, being formed with 2N pairs of alternate poles, transversely magnetized, the thin magnetized portion having over its working range a substantially linear demagnetization characteristic; wherein the two stator parts are connected exclusively by one or more non-magnetic spacers defining an air gap in which is fitted the thin magnetized portion of the movable member; and wherein the following relationship holds, ##EQU9## where, S fer is the section of one of the stator parts as measured in any radial plane defined by the radius passing between the two thin magnetized portions and a rotation axis of the movable member, S a is the surface area of one of the 2N pairs of the poles as measured in the plane normal to the magnetization, B fer is the induction in the stator, B a is the induction in the magnet, and the movable member clearance is limited so as to prohibit the displacement of the magnetized portion beyond an area wherein a release force becomes decreasing.