Study on Stabilities of Rotor-Bearing Systems With Different Types of Couplings

Nonlinear dynamic model of gear coupling is derived, dynamic equations of rotor-bearing systems connected by rigid coupling, gear coupling and flexible coupling are established based on finite element analysis, stability simulations and experiments are also performed. Simulation and experiment results show coupling type have important influence on stability of rotor-bearing system, instabilities of rotor-bearing systems coupled through rigid coupling and flexible coupling are caused by oil whirl or oscillation. Simulation result indicates instability of rotor-gear coupling-bearing system is induced by oil whirl or oscillation, however, experiment implies that the instability caused by self-oscillation of gear coupling which is earlier than oil oscillation caused. Threshold speed of stability of rigid coupling linked is highest, while gear coupling linked is lowest. This research results can provide important criterions for design and choosing of couplings and stable operation of rotor-coupling-bearing system.