Dynamic modelling of the defect extension and appearance in a cylindrical roller bearing

Local defects in cylindrical roller (CR) bearings usually occur on the contact surfaces. The ideal sharp-edged rectangular defect models given by the previous works are almost inconsistent with reality because their edge features are ignored. Many works think there are no difference in the evolution of defect edge and appearance between the ball bearing and roller bearing. Thus, the evolution of defect edge and appearance of roller bearing is not studied, which makes some difficults for formulating the roller slip and nonsmoothed surface of raceway. To solve the above problems, based on the defect edge features, the new defect extension and morphology modeling methods are proposed in this work. The effect of the evolution of defect edge feature on the vibrations of CR bearing is analyzed. The acceleration peak excited by the rolling element exiting the defect is related to the direction and the attenuation of bearing acceleration at this moment. The defect length has a significant effect on the acceleration peaks. The sudden change in the contact stiffness caused by the defect is one of the important reasons for bearing vibrations. A rigid rotor-roller bearing system with the defect is also introduced to study the effect of the defect on the rotor system. It can provide a useful method for improving the defective CR bearing dynamic modelling methods.