Dynamic Modeling and Vibration Response Analysis of Rolling Bearings With Composite Faults Considering the Influence of Elastohydrodynamic Lubrication

At present, in the dynamic modeling of rolling bearings with composite faults, Hertz contact theory is mostly used to describe the contact between the rolling element and the raceway, while ignoring the influence of lubricating oil film under elastohydrodynamic lubrication (EHL) on key modeling parameters, which brings errors to the accurate calculation of parameters such as stiffness and damping. On the basis of composite fault modeling, this article carefully considers the influence of EHL on the stiffness and damping of rolling bearings, establishes a five degree‐of‐freedom (DOF) composite fault model of rolling bearings, and verifies the correctness of the model through bench test data. The vibration response characteristics of rolling bearings with composite faults under different loads and fault sizes are mainly studied. The results indicate that the frequency‐domain characteristics of composite faults are the result of coupling and superimposing the frequency‐domain characteristics of single‐point fault signals. As the radial load increases, the amplitude of the vibration response also increases gradually. In the inner ring–outer ring composite fault and the outer ring–rolling element composite fault, the outer ring fault is more sensitive to change in radial load. If the radial load is appropriately increased, it is beneficial to identify the outer ring fault in both kinds of composite faults. However, excessive radial loads may inhibit the diagnosis of other fault frequencies other than the outer ring, which may affect the diagnosis of all components in the composite fault. In the inner ring–rolling element composite fault, the inner ring fault is more sensitive to change in radial load. If the radial load is appropriately increased, it is beneficial to identify the inner ring fault in the inner ring–rolling element composite fault. Similarly, in the diagnosis of such composite faults, excessive radial load may affect the detection and diagnosis of rolling element faults.