Torsional Vibration Research Of The Rolling Mill Main Driving System With Biting

The dynamic characteristics of the rolling mill main drive is torsional vibration., Tosome extent, there are some gaps in the main drive system due to the objective factors ofdesign, installation, manufacturing and wear, For example: There are inevitable backlashesbetween rolling roller head and coupling, cardan shaft fork and flat head, which willbecome larger slowly. Torsional vibration will be found in the main drive system whenthere are biting phenomenon in the mill. Then this phenomenon will be aggravated tosome extent because of the backlash. So that the vibration amplitude and torqueamplification factor (TAF) of the mill further increase，which is a serious threat to the safeproduction of the mill, also effect the quality of the product. Especially, Steel rollingindustry has developed rapidly to large-scale industrial，high-speed technology andautomation direction. With the increasing of the weight of work-pieces，the speed of therolling，and the constantly improving quality requirements，these problems are moreconspicuous. So, the research of the backlash main driving system with biting has acertainly realistic meaning.The F3mill of Baogang1580PC mill will be an example, according to the drawingsand measured data provided by the manufacturer, the F3rolling mill system is simplifiedas a "spring mass model"by using lumped mass method. A four and six-degree-of-freedomnonlinear torsional vibration model were established, the inherent frequency of the systemwas calculated, it was concluded that the design of the mill meet the optimal dynamicdesign criteria.Based on the established vibration model, in consideration of clearance, themechanics and mathematical model with nonlinear stiffness and damping was established.the dynamic equation of the system was solved and simulated by using the Matlab methodto analyze the vibration shape under the two situations not considering clearance orconsidering two clearance with biting. Compared the vibration response between the twocases, to obtain their displacement time diagram,torque amplification factor (TAF), andthe influence of the torsional vibration response in the condition of single backlash multi backlashes and different gap position in the main mill drive system, finally obtained theinfluence of the torsional vibration response in the condition of different gap sizes.