On-Load Characteristics of Local and Global Forces in Co-Axial Magnetic Gear with Reference to Additively Manufactured Parts of Modulator

Abstract

The paper presents an analysis of local and global forces acting on the ferromagnetic material of a modulator in a co-axial magnetic gear, taking several design variants and the impact of loading into account. The analyses include a modulator with cores manufactured from a soft-magnetic composite material and two variants made from electrical steel with laminations stacked in different directions. Variations of local forces acting on individual pole pieces of the modulator are analyzed at different loads, showing that the force spectra are subject to significant variation with an increasing load. The presented magnetostatic analyses are extended by structural analysis that provides estimation of stress and displacement for the modulator assembled from additively manufactured acrylonitrile butadiene styrene (ABS)-plastic parts. The analysis carried out for the least favorable design case of the magnetic circuit of the modulator shows that an application of the technology is significantly restricted by the magnetic gear torque volumetric density. Some changes to the modulator mechanical design are proposed in the paper to mitigate the drawbacks of this technology.

Forces in Axial Flux Magnetic Gears with Integer and Fractional Gear Ratios

“…The authors of this paper have been researching MGs for some time [21][22][23]; however, their main focus so far has been on coaxial MGs (CMGs, being also part of an RFMG). Taking into account the principle of operation of CMGs and AFMGs, the selection of rotor pole pairs (high-and low-speed rotors-p h , p l ) and ferromagnetic pole pieces (n s ) is identical.…”

“…A relatively small number of works concern the issue of MG's structural analysis, and in particular its crucial element-the modulator [19,20]. Ensuring the adequate rigidity of gear parts is a particularly relevant issue at the prototyping phase, using tools and additive methods, while this is not a significant problem for MGs with relatively short active length and low radial forces [21]. As shown in Ref.…”

“…Therefore, the main objective of this paper is to fill the knowledge gap by analyzing local interactions within modulator cores in terms of the rigidity of the entire AFMG modulator structure. While considering two AFMG configurations with integer (G r1 = 5:1) and fractional (G r2 = 5.5:1) gear ratios, the authors also wish to consider the radial unbalanced magnetic forces (RUMF) derived from RFMGs [21]. In this paper, we focus on a detailed decomposition of local forces and the analysis of their components in terms of magnetic pull reduction, pulsation reduction and modulator rigidity, keeping the total air gaps' thickness constant; these being challenging issues not yet deeply considered.…”

Simplified Design of Magnetic Gear by Considering the Maximum Transmission Torque Line

“…The number of pole-pairs at high-speed rotor is 2, which required four PMs, while the number of pole-pairs at low-speed rotor is 10, which required 20 PMs. Thus, the number of pole pieces is 12, which is the sum of the number of pole pairs at both high-speed and low-speed rotors, as in Equation (2). The magnetic gears are designed with 0.5 mm air gaps between the rotors and the pole pieces, as the narrower air gaps increase the permeance and reduce the flux resistance.…”

“…Since 1901, magnetic gears (MGs) have been developed as an alternative to the mechanical gear with the use of permanent magnetic force. Unlike mechanical gears, magnetic gears make a contactless speed conversion with a very efficient torque transmission performance, inherent to overload, reduced audible noise, and lubrication-less systems [1,2]. The transmission torque is an important output to meet the demand of its application, especially from the conversion of high-speed input to low-speed output.…”