Rolling bearing is one of the important parts of gear transmission system. The sliding friction between gear shaft and box body is converted into rolling friction, so as to reduce friction loss. Rolling bearing is mainly composed of rolling element, inner ring, outer ring and cage. Local faults such as pitting corrosion, fatigue spalling and cracks will occur on the surface of rolling bearing during operation, which will cause extra vibration and noise in the process of smooth operation of rolling bearing, and even directly cause the failure of rolling bearing, which will affect the smooth operation of the whole gear transmission system, and even cause major accidents such as economic losses and even casualties. In order to ensure the safe, stable and effective work of gear transmission system, it is necessary to carry out state detection and fault diagnosis for rolling bearings.
Fault mechanism is to reflect the cause and effect of fault, and is the basis of fault diagnosis. Therefore, strengthening the research on vibration response mechanism of fault shaft can better find the signal reflecting the essential characteristics of fault, find the source of fault signal, establish the mapping relationship and internal relationship between fault and its characterization, so as to combine with fault diagnosis technology to realize the accuracy of rolling bearing fault Diagnosis and identification, reduce the economic loss caused by bearing failure. For decades, scholars at home and abroad have done a lot of research on dynamic model and fault vibration mechanism of rolling bearing.
McFadden and Smith proposed a dynamic model of bearing with a single local fault on the inner raceway. In this model, McFadden and Smith used a simple pulse function to replace the impact attenuation function of the rolling element passing through the inner raceway fault. The vibration characteristics of the bearing with single fault in the inner raceway under the constant radial load were obtained. Although the model is relatively simple, it is the first dynamic model of bearing failure based on analytical formula. Later, many scholars used this analytical formula to analyze the vibration response of the fault bearing.
Tandon and Choudhury used square wave, triangular wave and half sine wave to simulate the impact caused by local damage of rolling bearing. The dynamic equation of the model was solved by analytical method, and the impact of impact and load on the amplitude of the bearing was analyzed. Sassi et al. Established the dynamic model of the fault bearing considering the oil film stiffness and oil film damping between the rolling element and the raceway, and derived the calculation formula of the impact force of the rolling element passing through the fault area of the raceway according to the kinetic energy principle.