Magnetic thrust bearing with high force modulation capability

Claim 1

In an electromagnetic axial thrust bearing comprising a rotating member for turning about an axis, at least one stationary member fixed relative to the axis of the rotating member, means for generating a m.m.f. associated with said stationary member, said rotating member and stationary member having adjacent faces in close proximity, said rotating member, stationary member, and m.m.f. generating means arranged so that the path of magnetic flux resulting from said m.m.f. generating means passes from the stationary member to the rotating member and back, magnetic flux lines passing between the stationary member and rotating member having a component in the axial direction resulting in a magnetic attraction between the members that produces a restraining thrust force, the improvement comprising: said stationary member comprised of a solid ferromagnetic material having at least one of arc-shaped grooves substantially concentric with the turning axis of the rotating member, said groove being lined with laminates of a ferromagnetic material thus defining a lined groove, said groove being defined by two sides and a bottom, the long axes of laminates at the bottom of the groove being substantially in the radial and circumferential directions and the long axes of laminates at the sides of the groove being substantially in the axial and circumferential directions, said m.m.f. generating means comprising a coil laid into the lined groove of the stationary member, and said rotating member having a groove facing the groove in the stationary member, said groove in the rotating member having laminates of ferromagnetic material stacked therein, the long axes of the laminates in the groove on the face of the rotating member being substantially in the radial and circumferential directions.