Research on the nonlinear resonance response of the high-speed spindle system supported by preloaded ball bearings

This paper presents a comprehensive study on the nonlinear resonance response of the high-speed spindle system supported by preloaded ball bearings. Firstly, the nonlinear stiffness characteristic of the ball bearing-rotor system is studied based on the analysis of the contact nonlinearity and geometric nonlinearity generated by supporting ball bearings. Secondly, a simplified rigid rotor system is built to discuss its nonlinear “soft-spring” and “hard-spring” stiffness effects across varying speeds and external loads. Thirdly, the nonlinear resonance response mechanism of the spindle system near its 1st-order equivalent linear resonance frequency is predicted, and the effect of “soft-spring” and “hard-spring” stiffness characteristics on its resonance response mechanism is detailed analyzed. Finally, a hybrid-supported experimental spindle system is built to verify the theoretical prediction results on the nonlinear resonance response of the preloaded ball bearing-rotor system. The results show that the resonance response curves of the rotor system exhibit the leftward “bending” characteristic corresponding to the “soft-spring” stiffness effect under the low speed and light load ranges, while exhibit the rightward “bending” characteristic corresponding to the “hard-spring” stiffness effect under the high speed and heavy load ranges.