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Shock and Vibration
Volume 2016, Article ID 2787524, 10 pages
Research Article

Dynamics Analysis of Unbalanced Motorized Spindles Supported on Ball Bearings

1College of Mechatronic Engineering and Automation, National University of Defense Technology, Changsha 410073, China
2The State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044, China

Received 21 January 2016; Revised 1 August 2016; Accepted 16 October 2016

Academic Editor: Gianluca Gatti

Copyright © 2016 Junfeng Liu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper presents an improved dynamic model for unbalanced high speed motorized spindles. The proposed model includes a Hertz contact force model which takes into the internal clearance and an unbalanced electromagnetic force model based on the energy of the air magnetic field. The nonlinear characteristic of the model is analysed by Lyapunov stability theory and numerical analysis to study the dynamic properties of the spindle system. Finally, a dynamic operating test is carried out on a DX100A-24000/20-type motorized spindle. The good agreement between the numerical solutions and the experimental data indicates that the proposed model is capable of accurately predicting the dynamic properties of motorized spindles. The influence of the unbalanced magnetic force on the system is studied, and the sensitivities of the system parameters to the critical speed of the system are obtained. These conclusions are useful for the dynamic design of high speed motorized spindles.