Research On The Torsional Vibration Of Main Drive System Of 4300 Plate Rolling Mill

In order to meet the demand of market, Shouqin develops the high strength steel plate continuously, the cross shaft type universal coupling of 4300 plate mill’s main drive system occurs fracture accidents several times in this process, which not only affect the orderly production, but also cause significant economic loss. Known from the analysis of previous similar cases, the incident is likely to be caused by torsional vibration, in order to research the reason of the accident, this paper studies the torsional vibration of main drive system with the combined method of theoretical analysis and testing.Firstly, the online main drive system is measured by using the wireless torque and strain testing system. Secondly, the mechanical model of main drive system is established with the centralized mass method, the moment of inertia and torsional stiffness of each component are calculated, the natural frequency and main mode are calculated. Then the dynamic response of system during the biting time is analysed, the torque amplification factor of each shaft is calculated, and the impact of rolling torque, damping rate and the time of biting on torque amplification factor is analysed. The analysis of the dynamic response of system under external load of different frequency is done, the power amplification factor of each shaft when frequency is different is calculated. The self-excited vibration of system when roll is slipping is simulated, the condition for the formation of self-excited vibration is obtained, the impact of rolling force and motor speed on the torque amplification factor when self-excited vibration occurs is discussed. Finally, the finite element analysis of fork and cross shaft in universal coupling is done with Workbench software, their fourth strength and fatigue strength are checked.Through the analysis we found that: the natural frequency of main drive system meets the power design criteria; the dynamic characteristic of main drive system under the load of biting steel and different frequency is good; by controlling the rolling force can effectively reduce the probability of the formation self-excited vibration; the fracture of the cross shaft type universal coupling is caused by fatigue.The research of this paper is completed by comparing results of the theoretical analysis and the test, they are consistent, this proves that the analysis is reliable, the result of research is of important guiding significance for the practical production of the 4300 rolling mill.