Design Research On The Magnetic Field Modulated Concentric Gear

As a new type of gear drive device, the magnetic gear mainly depend on themagnetic coupling to transmit torque and rotational speed. There is no mechanicalcontact between the input and output, therefore, the magnetic gear with low noise, highefficiency, easy maintenance, high reliability and overload protection, etc. Mgneticgear drive device provide the transmission industry to a new direction.However, the magnetic gear rotation device has its inherent drawbacks, lowtorque density has been the main factor restricting the development of magnetic gear.In recent years, due to the emergence of rare earth permanent magnet materials,magnetic gear transmission torque increase, but the traditional radial magnetic gearsdepends on a small part of the permanent magnet magnetic field which are close toeach other in the torque transmission, the utilization of permanent magnet is low andthe magnetic gear torque density is not high. Modulated magnetic field concentric gearis a new topology magnetic gears. During the transmission of torque all of thepermanent magnet magnetic fields are involved.So the torque density of this kind ofmagnetic gear can be achieved100kN.m/m3.Based on the analysis of this kind ofmagnetic gear, the external rotor structure is changed, and the changing impact of theouter rotor air-gap magnetic field studied compared with the original model.Calculated and analyzed the parameters which have big impact on the magnetic gear,such as the width of the modulated ring and the permanent magnet’s width and heightof the outer rotor finding out the effect on the transmission torque with the parameterschange. According to the optimization methods of permutations and combinations,give a calculation scheme of the magnetic gear according to the maximum static torqueof the inside and outside the rotor, loss and average torque density to determine theoptimal design plan. And then follow the non-uniform air-gap design method changethe inner rotor permanent magnet, to increase the efficient harmonic content of theouter rotor air gap. In addition, with the help of the Lanzhou Electric Corporation, theouter rotor improved magnetic field modulation concentric gear prototype is made andthe dynamic performance of the magnetic gear is studied, and the performance isverified by the experimental results which also lied the foundation for the applicationof the magnetic gear.