Dynamic force transmissibility of flywheel rotor systems supported by angular contact ball bearings considering clearance fit

Abstract

This study investigates the dynamic force transmissibility (DFT) of angular contact ball bearings (ACBB) supported flywheel rotor systems (FRS) considering the clearance fit. By introducing the influences of combined load and contact angle variation in the Jones formula, the internal load distribution and nonlinear stiffness of ACBBs are accurately solved. The rigid inner/outer ring contact model is adopted to characterize the clearance fit between the ACBB outer ring and mounting sleeve. Based on the Hertzian contact theory, the discontinuous and nonlinear support stiffness caused by the clearance fit is obtained analytically. The lateral vibration model of the FRS considering the fit clearance and ACBB nonlinear support stiffness is established. Combined with the harmonic balance method and alternative time/frequency technique, the DFT of the system is determined, and the stability of the results is proved. Numerical integration and dynamic tests are used to verify the accuracy of the analytical model and solution method. Based on these, the effects of unbalanced mass, fit clearance, axial preload, and rotor damping on the DFT are discussed. The support stiffness of the FRS is nonlinear after considering the ACBB and fit clearance. The amplitude of the unbalanced mass determines the nonlinear characteristics of the system. Increasing the fit clearance decreases the speed corresponding to the peak of the DFT curve. The resonant peak of the DFT curve shifts to the high-speed region with an increase in axial preload. In addition to increasing the peak value of the DFT curve, reducing the damping coefficient causes a soft-to-stiff alternation phenomenon in the system DFT curve. The results provide an important reference for designing a reasonable vibration isolation system to reduce the transmission of micro vibrations of the FRS to a spacecraft platform.