Magnetic gearbox for automotive power transmissions: An innovative industrial technology

Conventional coaxial magnetic gears are structures with permanent magnets, which working principle is equivalent to that of epicyclic gearing. The motion is transferred between different axles, without contact in the rotating elements, by modulating the magnetic field generated by permanent magnets on inner and outer rotors of the machine, exploiting ferromagnetic poles in the middle rotor. The challenge of replacing standard mechanical gears in an automotive powertrain has led to the development of a new technology of paramount importance for the automotive industry which could solve several problems related to classical gears like, e.g. need of lubricant, wearing, vibration, noise, and need of friction material. In this paper a novel topology of magnetic gearbox is proposed. The presented solution is expected to have a higher reliability and efficiency compared to equivalent mechanical gearboxes, allowing the torque transmission from the power source (electrical or thermal) to the wheels, with a certain number of fixed gear ratios. Several topological solutions of magnetic gearbox are proposed, with possible application in different industrial fields. The gearshift phase has been dynamically analysed with an analytical approach and then a magnetic powertrain has been developed in Matlab/Simulink to validate the proposed technology, as alternative to the mechanical one.