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.