Analytical field calculation for linear tubular magnetic gears using equivalent anisotropic magnetic permeability

Abstract

Linear magnetic gears take the definite merit of direct force amplification or speed reduction without using any bulky, inefficient rotary-to-linear mechanism. In this paper, an analytical calculation approach to determine the performance of linear tubular magnetic gears is proposed. The key is to adopt the concept of anisotropic magnetic permeability to handle the field-modulation region which consists of iron rings and airspaces in a zebra-striped manner. By solving the Laplace's and Poisson's equations in the linear tubular magnetic gear, the corresponding magnetic field distributions can be analytically determined. Finally, the analytical calculation results are compared with the numerical results obtained from the finite element method, hence verifying the validity of the proposed analytical field calculation.