Effects of misalignment on the transmission characteristics of magnetic couplings

Abstract

Magnetic couplings possess no mechanical contact and permit higher assembly tolerance for transmitting torque from a primary driver to a follower by magnetic force. This paper investigates the eVects of misalignment on the transmission characteristics of synchronous magnetic couplings. The misalignment can be categorized into the following three types: transverse, angular and a combination of these two misalignments. Without loss of generality, an axial synchronous magnetic coupling is adopted in the present because of its simplicity both in design and fabrication. The phenomenon and in¯uence of shafts with assembly misalignment are described ®rst. The mathematical model for the magnetic coupling with misalignment is then constructed for the purpose of deriving the equations governing the torque transmission and force interaction characteristics. The method of equivalent magnetic charge is employed to calculate the variations in the transmitted torque owing to each type of misalignment. Finally, a test apparatus is constructed for verifying the static and dynamic characteristics of the designed coupling under various misalignment conditions. Good agreement between numerical simulation and experimental results is obtained.

Design and fabrication of magnetic couplings in vacuum robots

“…The results of each model, which were maximal coupling torque of PMC, were summarized in Table II in next subsection. The maximal torque is yielded when the twisted angle is half‐a‐pole pitch (Huang et al , 2001).…”

Development of a bearing-free, low-vibration vacuum chuck for a spin-coating apparatus

“…However, magnetic fields are never perfectly balanced and will always cause assemblies to shift to the lowest energy state. Consequently, all magnetic couplings require full mechanical support through radial and thrust bearings (Huang, Chen, Yau, & Sung, 2001;Wallace, Wohlgemuth, & Lamb, 1995;Yonnet, 1981).…”

Condition Monitoring of Forward Curved Centrifugal Blower Using Coast Down Time Analysis

“…Prabhakar et al [15] analyzed the transient response of a misaligned rotorcoupling-bearing system passing through the critical speed using the finite element method for flexural vibrations and found that the subcritical speeds at one-half, one-third, and one-fourth of the critical speed. The mathematical model constructed for the effect of misalignment on magnetic coupling [16] derived a set of nonlinear equations for parallel misalignment effect [17] between two rotating shafts and two rotor segments with angular misalignment [18]. Extensive experimental studies were made by researchers [19][20][21][22][23] on unbalance and misalignment [24,25], misaligned rotorball bearing systems [26,27], rigidly coupled rotors [28,29], and pointing complexity of diagnosis for misalignment and unbalance using vibration analysis.…”