Force and Stiffness of Passive Magnetic Bearings Using Permanent Magnets. Part 1: Axial Magnetization
Résumé
This paper deals with the calculation of the force and the stiffness between two ring permanent magnets whose polarization is axial. Such a configuration corresponds to a passive magnetic bearing. All the calculations are determined by using the Coulombian model. This paper also discusses the optimal ring dimensions in order to have a great force or a great stiffness between the rings. Such properties are commonly searched in passive magnetic bearings and we propose a three-dimensional method allowing to optimize these parameters. Furthermore, an important result is established in this paper: the exact relative position of the rings for which the force is the strongest depends on the air gap dimension. As the expressions presented in this paper give this exact relative position, manufacturers can easily optimize their passive magnetic bearings. It is noted that this result is new because the curvature effect is taken into account in this paper. Furthermore, such semi-analytical expressions are more precise than the numerical evaluation of the magnetic forces obtained with the finite element method. In addition, semi-analytical expressions have a low computational cost whereas the finite element method has a high one. Thereby, as shown in this paper, such calculations allow an easy optimization of quadripolar lenses or devices using permanent magnets.
Domaines
Electromagnétisme
Origine : Fichiers produits par l'(les) auteur(s)
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