Study effect of the back irons in passive magnetic bearings with alternating radially magnetized rings by using 2D analytical method

Abstract

Purpose Permanent magnet passive magnetic bearings (PMBs) are used for suspension of rotating shafts in one direction. PMBs with alternating radially magnetized rings having back iron is one of the most optimum configurations among all configurations of PMBs. This paper aims to investigate the effect of the conductivity and permeability of these back irons on the stiffness and damping of the configuration. Design/methodology/approach The stiffness and damping of the configuration will be calculated through a 2D dynamic analytical method and validated by FEM simulations. Findings The results of the paper show how the permeability and conductivity of the back irons can affect stiffness and damping of PMB. Furthermore, the size of the magnets and the air intervals between them are optimized for maximum stiffness and damping. Originality/value The results show that these bearings can have some intrinsic damping without any loss of stiffness, which can be useful for many applications.