Magneto-mechanical Design and Development of a Coaxial Magnetic Coupling with Optimization of Torque to Mass Ratio

This work covers the design and analysis of a coaxial magnetic coupling with the aim to optimize the torque to mass ratio. Magnetic couplings provide several unique benefits over standard mechanical couplings that are made possible via magnetic torque transmission including reduced maintenance, greater tolerance for misalignment and intrinsic overload protection. The main disadvantage of magnetic couplings is that their torque to mass ratio is significantly lower than equivalent mechanical couplings. 2D magnetostatic and 3D finite element mechanical models are used to analyze the proposed coupling geometry and ensure it can transfer a maximum torque of 224 Nm and operate at a steady rotational speed of 1000 RPM. The relationship between the magnetic design parameters (pole pairs number, air gap, etc.) and the target performance parameters (torque and relative rotor angle) are established and used to develop a rotor geometry that maximizes the peak static torque. A parametric static stress analysis of the coupling geometry is also performed to reduce its mass and obtain an optimal torque to mass ratio. Finally, the torque to mass ratio of the optimized magnetic coupling is compared with mechanical couplings to demonstrate improved practicality of the design.