No abstract

A vertical vibration model of a 3-DOF strip rolling mill with a compound roll bearing failure on the outer raceway and inner raceway is established. Through MATLAB simulation, the vertical vibration characteristics of the strip mill work roll are compared and analyzed under the condition that the outer raceway failure of the roller bearing remains unchanged, the inner raceway failure changes and the inner and outer raceway failures change simultaneously. It provides a certain theoretical basis for further clarifying the non-linear vibration mechanism of the rolling mill caused by the compound bearing failure. At the same time, when the internal and external raceways of the roller bearing have a compound failure, the effects of different roller numbers and contact angles on the vibration displacement fluctuations of the work roll are analyzed, which has certain theoretical guidance for the optimization design of the roll bearing.

Considering the influence caused by a early single pit defect on the outer raceway of the work roll bearing, a 2-DOF plate strip rolling mill vertical vibration model with a single point weak fault on the outer raceway was established. With the practical parameters of the roughing mill of the 1780 hot continuous rolling mill, the vertical vibration characteristics of the rolling mill work roll with different rotating speed and different single pit defect area on the bearing outer raceway are analyzed by numerical simulation. It is found that with the change of the rotation speed of the work roll, different nonlinear vibration behaviors occurred, such as superharmonic resonance, main resonance, combined resonance and sub-harmonic resonance. Especially the subharmonic resonance of the work roll is more harmful than the main resonance when the work roll speed is twice the rotation speed corresponding to the first and second natural frequency of the rolling mill. This work provides a theoretical basis for further clarifying the effect caused by a early defect of the work roll bearing on the mill vibration.