Dynamic Characteristics Of Parallel Shaft Gear Rotor System

With the increase of rotational speed of rotary and the improvement of its performance, the vibration characteristic of the rotor system has been becoming a research focus. The gear rotor system is applied abroad and it has become a very important research field. Because of the gears meshing, bending vibration and torsional vibration of rotors is coupling. We can't analyze the dynamics character of rotors system with only one rotor. In order to analyze the dynamics character of gear rotor system, the lateral-torsional coupling vibration model must be set up.Transfer matrix-impedance coupling method, which is commonly used, was introduced to study the dynamic characteristics of rotor systems. A deep study was conducted later in the paper. This method was verified by the isotropic and anisotropic examples, the results show that this method is accuracy enough to deal with complex rotor system with complex anisotropy.Then in accordance to the definition of mechanical impedance, the relationship between impedance and displacement for spur gear unit was established. The model of parallel shaft gear rotor system considering lateral-torsional coupling was built. Frequency equation of the model was got by transfer matrix-impedance coupling method. Through the analysis of the results, it can be proved calculation error will become large if lateral-torsional coupling wasn't taken into account.Nonlinear dynamic model of two-stage gear-rotor system with nine degrees of freedom and the nonlinear dynamic model with the elastic support of the 13 degrees of freedom were built, while the oil film force and tooth separation was considered. After the analysis of numerical method, there was chaotic motion caused by tooth separation when speed over a certain value. Change of tooth separation had a great influence on the chaotic region; comparing with the over-loading, light-load situations was tender possible to set off the tooth, the system running more smoothly in overloading; Stiffness of elastic support system affected the size of region-wide chaos, so when the work speed was determined, the appropriate adjustments with the stiffness of bearing basis and base, the work speed can avoid from the chaos to reduce damage to the system.