| Rolling bearing is an indispensable basic mechanical component in rotating machinery.With the development of materials,heat treatment,ultra-precision grinding,measurement and calculation technology,bearing performance and service life have been greatly improved.However,there are still a large number of bearings due to lubrication failure resulting in premature bearing damage,which leads to the operation failure of the main engine.Therefore,it is important to improve the lubrication status of bearings to reduce the frictional torque and vibration,reduce bearing wear,and extend the bearing life with theoretical research and engineering application value.This paper through to investigate the mechanism of the effect of composite nano additives and micro morphology of thickeners on the tribological performance of grease and bearing performance improvement,which provides a good lubrication scheme for bearings with low friction coefficient,low wear rate,high precision,long life,low noise and high reliability.the following is the major research of this paper:（1）The tribological and vibration suppression properties of calcium sulfonate complex grease contain mixed nanoparticles were studied.Poly-α-olefin 40（PAO40）was used as the base oil to prepare the calcium sulfonate complex grease,the base nanoparticles were Mo S2,and the different hardness of Cu O,Si O2,and Al2O3 were selected as the second nano additives The microstructure of calcium sulfonate thickener and nanoparticles was studied by SEM.The tribological properties of five nano-greases were studied by a four-ball tribological and wear testing machine.The optical microscopy,EDS and XPS were used to characterize the wear surface of steel balls,as well as the friction coefficient of nano-grease and the wear surface of steel balls were analyzed and discussed.The friction and wear mechanism of mixed nanoparticles and calcium sulfonate thickener under the synergistic action in the contact area was explained.The vibration performance of the five nano-greases were tested by BVT-1bearing vibration tester with 6204 steel bearing as the test bearing.The three-band analysis showed that after the addition of Mo S2 nanoparticles the low and high-frequency vibrations of the bearings were suppressed,and the high-frequency vibration of the bearing was further reduced by adding oxide nanoparticles.The wettability test shows that the contact Angle of PAO40 base oil on the thickener surface of calcium sulfonate complex grease containing Mo S2and Si O2 nanoparticles is the smallest,and it can be quickly added to the raceway.（2）Study the influence of thickener structure on grease tribology and vibration and friction of hybrid ceramic ball bearing were studied.Lithium,polyurea and calcium sulfonate complex greases were prepared with PAO40 as the base oil,and the physicochemical properties and functional groups of the three greases were examined.The microstructure of the three greases thickener was observed by SEM.The influence of the morphology of thickeners on the tribological properties of Si3N4/GCr15 contact surfaces was studied.The optical microscopy,SEM and XPS were used to characterize the worn surface of the steel plates,as well as the friction coefficient,wear width and worn surface morphology were analyzed and discussed.The mechanism of the thickener in boundary lubrication and mixed lubrication was explained.The vibration and friction torque properties of three greases in 6204 hybrid ceramic ball bearing were evaluated by BVT-1 bearing vibration tester and BFT-1 bearing friction torque tester.The results show that LG is subjected to the continuous shear of the ceramic ball,which releases a large amount of base oil and the broken thickener to form a thick oil film in the center of the raceway,which makes the bearing in a mild lubrication state,effectively suppress the bearing vibration and reduces the friction torque. |
