Research On Torsional Vibration Effect By Rolling Mill Main Drive System From Clearance Impact

The main drive system of rolling mill has a complex structure. Owing to the objectivefactors of design, installation and runtime of wear cause the clearance of a certain size atcardan shaft and palm end of roller in practical projects. Generally, the clearance of themain drive system will not open during the rolling process. However, the clearance mayoccur opening when the load changes. Especially the rolling mill slipping lead to theclearance of the main drive system opening, repeated impacts caused the system to moresubstantial torsional vibration, and leaded to the torque amplification factor (TAF) toolarge. Eventually, fatigue loss of transmission parts caused a serious adverse impact on thesafe operation of the mill.In this paper,5m heavy plate mill by Baosteel as an example. Thefour-degree-of-freedom discrete models were established by lumped mass method, whichare linear dynamics model and nonlinear dynamics model with clearance. The naturalfrequency and the main vibration mode was analyzed, found that the rolling mill meet thebest dynamic design criteria.For the torsional vibration of the rolling mill in the slipping, and used theRunge-Kutta method to solve the response of the system. Analysis of the dynamicresponse of linear system, found that the TAF of shaft section is not large in the slipping.Based on analysis of nonlinear dynamic response with clearance, the place of clearanceappeared repeated impacts, each oscillator of the relative displacement appear a largeamplitude, the TAF of shaft section became larger, especially the TAF of shaft sectionclose to the clearance are particularly sensitive. Analyses a main drive system with threeclearances, and found that the more clearance for main drive system of torsional vibrationthe more obvious influence.Finally, the system including all kinds of clearance is analyzed, discussed theinfluence of TAF on the size of clearance; number and the position of the shaft section,compare the single-clearance and double-clearance system. This study provides referencefor the research on different clearances control of mechanical system, especiallymulti-clearance system.