Theoretical computations of the magnetic coupling between magnetic gears

The torque of magnetic coupling with different magnetic poles has been investigated by theoretical computations with both 2D and 3D modelling processes of the finite element analysis. The torque can be increased by increasing the number of poles for magnetic coupling between magnetic gears with 2 mm separation distance, provided that the number of poles is less than 10. However, the torque is inversely proportional to the number of poles when its number is larger than 10. This phenomenon is explained by analyzing the magnetic coupling strength of different poles. The 3D computer simulations are in excellent agreement with the experimental values. The 2D computer simulations can be improved by a "two magnetization vectors within a pole" technique; i.e. by properly rotating the angle between the two magnetization vectors.