Research On Service Performance And Failure Behavior Of Self-lubricating Spherical Plain Bearing

The self-lubricating spherical plain bearing is an important basic moving component which is widely used in aerospace and industrial equipment.With the rapid development of the aerospace industry in recent years,the self-lubricating coating(or the film)has received extensive attention.Thus,the coated self-lubricating spherical plain bearings,a new type of spherical plain bearing,have gradually attracted increasing attention,and extensive research has been conducted on them.Most of the current studies have been conducted on gasket-type self-lubricating spherical plain bearings.However,the failure behaviour and mechanism of the coated self-lubricating spherical plain bearings have not been studied in detail.With various high-tech fields put forward higher requirements for the service performance and reliability of the self-lubricating spherical plain bearings,it is urgent to develop new types of bearings and conduct comprehensive research on them.Therefore,in this paper,the coated self-lubricating spherical plain bearing is the main research object.Moreover,the simulated wear life experiment is conducted to thoroughly analyse the service performance,the failure behavior and mechanism of the bearing.The wear failure behaviour of the coated self-lubricating spherical plain bearings under the light-load and low-frequency conditions was studied using the self-made swing wear life tester.The commercial GE17 ES bearing was the main research object,and the wear state of the bearing was monitored in real time using torque and temperature rise signals.Furthermore,a scanning electron microscope and X-ray energy spectrometer were adopted to analyse the wear failure mechanism of bearings preliminarily.The results indicate that the friction torque and temperature rise signal changes were mainly divided into three stages,and the characteristics of similar changes could be maintained under different working conditions.Furthermore,at the end of the bearing life,the torque and temperature rise had abrupt changes almost at the same time,which indicated the occurrence of bearing failure.In general,the wear failure mechanisms of bearings included abrasive wear and adhesive wear.Moreover,there were fatigue wear and oxidation wear under some conditions.The torque and temperature rise comprehensively reflected the service state of the the coated self-lubricating spherical plain bearings,which could be used as a physical criterion for determining bearing failure.Furthermore,the staged life test was further designed.The relationship between the evolution of the bearing surface structure and the degradation of the service performance was analysed using the microscopic inspection method.The results indicate that during the normal service phase,the smooth area ensured the stable operation of the bearing.Conversely,during the signal mutation phase,the accumulation of damage on the substrate surface caused rapid failure of the bearing.In general,the main wear failure mechanisms of the bearing included plastic deformation and abrasive wear,and oxidation wear accelerated the bearing failure.These results revealing the damage and failure evolution process of the coated self-lubricating spherical plain bearings could provide a theoretical basis for future studies on the wear failure of multiple types of bearings.