Basic Research On Ultrasonic Vibration Assisted Swaging Process For Aviation Self-lubricating Spherical Plain Bearing Assembly

Aviation self-lubricating spherical plain bearings are the key parts of aerospace vehicles,which are widely used in the important active joints.The swaging assembly process is the core process of self-lubricating spherical plain bearings engineering application,which is the key technology to ensure the bearing service performance.However,the traditional swaging assembly process has great influence on the no-load starting torque,and the swaging tool is easy to scratch the machining surface,which seriously affects the performance reliability of the assembled bearings.In this paper,an ultrasonic vibration assisted swaging assembly process is proposed for improving the deficiencies of traditional process,and the relevant basic research is carried out.In terms of processing mechanism research,the effect of ultrasonic vibration on the plastic deformation behavior of the outer race material was studied.From the aspects of high strain rate dynamic mechanics theory and the material constitutive relationship under ultrasonic vibration conditions,combined with the ultrasonic vibration rolling experiment of the outer race material,the effect of ultrasonic vibration,vibration amplitude and rolling static load on the plastic deformation of the outer race material,the friction condition of the processing surface,and the depth of the plastic deformation layer were revealed.At the same time,using the material compression test under ultrasonic vibration conditions,the constitutive relationship of the outer race material under ultrasonic vibration was obtained.Forming load is the most important process parameter of the swaging assembly process.Therefore,in this paper,the forming load had been studied in detail,established and validated the analytical model of the forming load,and analyzed the main factors affecting the forming load after applying ultrasonic vibration.Combined with finite element numerical simulation methods,the key process parameters of the swaging assembly process were optimized.In order to reveal the ultrasonic vibration assisted swaging mechanism from the material level and evaluate the corrosion resistance and fatigue resistance of the processing surface,the microstructure of the outer race material after ultrasonic vibration surface rolling was observed by scanning electron microscopy and XRD.The surface morphology,surface hardness and residual stress of the outer race material after ultrasonic vibration surface rolling were tested,and the influence of ultrasonic vibration on the surface quality of the outer race material processing suface was investigated.Based on the microstructure and surface quality of the outer ring material treated by ultrasonic vibration surface rolling,the corrosion resistance and fatigue resistance were analyzed.In terms of process research,the experimental research of ultrasonic vibration assisted swaging assembly process was studied.Based on the ultrasonic interface transfer characteristics and the ultrasonic vibration system load characteristics,the load analysis of ultrasonic vibration assisted swaging assembly process was carried out.A design scheme of ultrasonic vibration assisted swaging tool was proposed,and the swaging tool for a specific type bearing was manufactured and the swaging assembly experiments were completed.The surface processing quality and no-load starting torque of the assembled bearings and the forming load during the swaging assembly process were detected,the results of which verified the theoretical research conclusions of the influence of ultrasonic vibration on plastic deformation behavior,processing surface quality and forming load.These work laid the foundation for the engineering application of the ultrasonic vibration assisted swaging assembly process.