Dynamic Analysis Of Coupled Bevel-Geared Rotor-Bearing System

Gear system is an important component of the mechanical engineering system, and its performances affect the characteristics of geared rotor-bearing system. With the increase of rotational speed and power, gear transmission is increasingly developing toward to high-speed and large load, and researchers focus on the dynamics of the system. Because gear transmission system in our country, especially bevel-geared one is generally more serious than foreign products on vibration and noise, studies of the gear dynamics is one of the important issues to be urgently solved.This dissertation mainly study on a typical mechanism with bevel-geared rotor-bearing, and discussed the influences of critical speed, stability and unbalanced response under different external torque, the main contents and conclusions are as follows:Firstly, the structure and principle of the main machines of the system is analyzed, and a coupled axial, lateral and torsional dynamic model of the system is established. Then, the motion equations of the system is derived using Lagrange equation, and the dynamic analysis of the bevel-geared rotor-bearing system such as the critical speed, stability, and unbalance response are discussed. The dynamic influences of rotor-bearing system at different external torques are also investigated in the dissertation, and the steady state response due to unbalances of different bevel gears are proposed in the cases such as under different external torques and different types of supporters. The main conclusions are as follows: (1) The main source of vibration in coupled bevel-geared rotor-bearing system is the displacement constraint relations between the bevel-gears. The axial, lateral and torsional vibrations are coupled each other, and can not be analyzed separately; (2) In the calculation of critical speed or natural frequency of the bevel-geared rotor-bearing system, the traditional methods, or uncoupled one may be missing some important modal information; (3) Because of the axial, lateral and torsional coupling effect, the external torques can change the bearing characteristics and affect the dynamic behaviors of the entire system; (4) The different types of supporter have a greater influence of the unbalanced response on the rotor which the bearing is, and have less effect of other rotors.