A linear magnetic bearing with integrated long stroke propulsion - design and realization of an IU-module

The active magnetic bearings (AMB) and linear electrical actuators (LEA) are the important elements for high precision systems such as semiconductor equipment and machine tools. This paper concerns the initial design of a single I U-shaped electromagnetic module as a part of six degrees of freedom (6-DoF) contactless sliding system reached by integration of electromagnetic and mechanical structures of magnetic bearing and electrical actuator. The initial performance (magnetostatic behaviour) of the non-optimized electromagnetic module is investigated. Its vertical suspension forces (1), depending on the bias flux originated from the permanent magnets and planar position of the rotor, are obtained by means of the numerical solutions for electromagnetic field and application of the Coulomb virtual work (CVW) principle. The results obtained by means of finite element models (Ansys 3-D and Maxwell 3-D software packages) are validated by measurements. It allows the understanding of the electromagnetic behavior, flux leakage distributions in the air gaps, values of the generated forces in the contactless sliding system and further evaluation of the structure.