Linear variable reluctance (VR) micro motor with horizontal flux guidance: concept, simulation, fabrication and test

This paper reports on a novel concept and realization of a variable reluctance micro motor consisting of a high aspect ratio fabricated stator and a separate traveler guided by friction or ball bearings. The flux is generated and guided in plane by a three dimensional meander coil wound around laterally toothed stator poles. The traveler´s comb shaped poles reach in between the stator poles and therefore are attracted from both sides. Thus, the attraction forces exceeding thrust, common to any VR-motor concept, are eliminated. The magnetic NiFe-structures and Cu-conductors are fabricated by electroplating through high aspect ratio photolithographic masks. SU8 photo epoxy is used as embedding material enabling the realization of high aspect ratio via interconnects.