Influence of lubrication state transition on dynamic characteristics of deep groove ball bearing with localized defect in thermal environment.

The accuracy of the vibration response in a defective bearing dynamics model depends on the precise representation of the lubrication friction state between the rolling element (RE) and the raceway within the model. In this study, a fault dynamic model for outer ring defect of deep groove ball bearings (DGBBs), considering the lubrication state transition in a thermal environment, is established. This model accounts for the asperity contact effect during the lubrication state transition and integrates the lubrication-friction model for temperature changes into the dynamic model when skidding occurs. The influence of lubrication state change on the fault frequency of outer ring of DGBB in thermal environment is studied. The experimental and simulation results indicate that the lubrication state of the bearing is gradually deteriorated from elastohydrodynamic lubrication to mixed lubrication with the increase of working temperature. The transformation of the lubrication state is shown to have a significant effect on friction, resulting in the fault frequency of the outer ring increasing with temperature, which exhibits substantial deviation in the thermal environment. In the temperature range of 30 °C–150 °C, the deviation of defect frequency reaches 15.5%, which affects the accuracy of bearing fault diagnosis. This study may offer recommendations for enhancing the condition monitoring of rolling bearings under extreme working conditions. • The asperity contact effect between rolling element (RE) and raceway is considered to improve the accuracy of the system. • The lubrication state of bearing deteriorates as temperature rises, resulting in a decrease and then an increase in friction. • The nonlinear change of friction affects the speed of RE and cage, and the dynamic behaviors of bearing change significantly. • The change of cage speed modulates the outer ring fault frequency of bearing, which causes an obvious frequency deviation. [ABSTRACT FROM AUTHOR]