Mathematic Modelling and Numerical Analysis for a Novel Inner-Type Nutation Magnetic Drive

Abstract

This paper presents an inner-type of magnetic gears for non-contact driving, based on the nutation gearing principle. An improved three-dimensional analytical model, based on the magnetic vector potential of rectangular permanent magnets, via the equivalent current, is deduced for the proposed nutation magnetic gears. The transformation of coordinates is applied for a global field solution. The analytical model and the finite element model have analyzed the output torque of the nutation magnetic drive, respectively. The results show that the values calculated by the two models are consistent. The proposed analytical model can provide a reference for the design and optimization of nutation magnetic gears and other permanent magnetic mechanisms with rectangular magnets.

Concentric Magnetic Gear without Separate Modulator Structure - A Theoretical Study Based on Harmonics Interaction

“…Chosen value of outer gear sp eed ω o Apply equation ( 11) at a particular position θ, evaluate total over a full rotation 2π, using equations ( 14) to (16). Some of the relevant results from the simulation of the equations are shown in Fig.…”

“…There has been some research done [15][16][17] using harmonic magnetic gears and nutation magnetic gears where air gap variation is done differently to modulate the magnetic field as the gear rotates. It is true that harmonic gears also do not need a separate modulation structure.…”

“…So, in terms of parts count the design has its complexity. Nutation magnetic gears [16,17] use a different process, where there is a nutation sleeve at angle with respect to the input shaft. One set of permanent magnets is attached to a rotor connected to this bent shaft.…”

“…This leads to air gap variation between the two sets of rotors and hence the variation of magnetic field strength. There is also a guide pin connected to the housing of the whole gear system to constrain the motion of the rotor connected to the bent axis [16]. So, even though this nutation gear does not have a separate modulator structure, it also has complexity in its design.…”