Modeling and simulation of a new dynamic balancing system based on magnetic interaction

Abstract

This paper presents a new type of dynamic balancing system, having a driving solution of the rotating part based on magnetic interactions. The magnetic system also plays the role of an elastic bearing. The technical solution allows the dynamic balancing evaluation depending on the radial displacement between two disks with permanent magnets. If the tested part, a disk subjected to balancing, has a dynamic unbalance, this will create a centrifugal force. Due to the finite stiffness of the magnetic coupling, a displacement Δ in the radial direction will occur; the displacement Δ will increase as the centrifugal force will increase. The magnetic system is design so as the magnetic interaction force, which occurs between the centers of the permanent magnets, will be in opposition with the centrifugal force. The radial displacement is stopped when an equilibrium between the mechanical and magnetic forces occur. The magnetic forces are analytically calculated, using a 2D model, the value of these forces depending on the misalignment of the balanced part, against the equilibrium position. The calculation shows that the unbalance value is not dependent on its angular position, relative to permanent magnets arrangement on the disks circumference. Also, the magnetic force, which oppose to the centrifugal force caused by the dynamic unbalance, does not give a torque to the rotation center of the system. Due to the specific geometry it was necessary to create a FEM model of the magnetic system to validate the 2D analytical calculation model,. It was used a 3D simulation software, specific for these kind of problems - the INFOLYTICA software. The results allow built of a numerical model of the magnetic sub-systems and confirmed the feasibility of the proposed idea.