In this effort, the nonlinear responses and stability of a spindle system supported by ball bearings are presented. The dynamics of this system is described by a set of second order differential equations with a nonlinear piecewise smooth force. The Floquet theory is applied to investigate the stability of the periodic solution. Due to the loss of contact between the raceways and balls in the ball bearing, the bending of the frequency response curves switch to the left at the weak resonance region, which is similar to the frequency response curves of a system with a soft spring. With the decrease of the bearing clearance, the bending of the frequency response curves switch to the right, which is similar to the frequency response curves of a system with a hard spring. Increase of the frequency ratio, the bending of frequency response curves transforms from left to right. The route to chaos through a period doubling process is also observed in this spindle-bearing system.Keywords Spindle-bearing system · Piecewise stiffness · Floquet theory · Stability · Period-doubling bifurcation
InstructionAs one of the sources of vibrations in the spindle system, ball bearing attracts a lot of interests. To compensate the thermal and centrifugal expansion, initial clearance between the raceways and balls is designed for the ball bearing. A lot of efforts have been devoted to the study of the nonlinear responses and the routes to chaos of rotor-bearing system with clearance. In the early work of rotor dynamics, Yamamoto [1] considered the nonlinear effect of bearing clearance and investigated the vibratory behaviors of a vertical Jeffcott rotor supported by ball bearings. The results show that the maximum amplitude at the critical speed decreases with the increase of radial clearance. Following the effort of Yamamoto, Tiwari et al. [2] investigated the effects of the bearing clearance and varying compliance on the dynamic characteristics of a horizontal Jeffcott rotor with the unbalance force. Harsha et al. [3] analyzed the effects of surface waviness and bearing clearance on the nonlinear vibration response of rotor-ball bearing system. Bercea et al. [4] proposed a general methodology for modeling the relationship between the contact pressure distribution and the elastic deflection in several types of double-row rolling bearings with the effects of bearing clearance and the initial preload. Sopanen and Mikkola [5,6] proposed a dynamic model of a deep-groove ball bearing with six DOF. By investigating this model, the effects of the bearing clearance on the natural frequencies and the vibration responses of the rotor bearing system were studied. All the works presented in Refs. [1-6] mainly focus on the nonlinear response of the system with positive clearance. However, due to the thermal expansion of the races and balls of the bearing