Research On Traction Characteristic And Spin Effects Of Bearing Lubricating Oil In Point Contact State

In modern industrial areas,the performance of reduce friction and resist wear is one of the most important problems to be considered in the mechanical industry.In the mechanical rotary transmission equipment,the bearing is often used to reduce the friction between the contact pairs,to increasing service life of the equipment and guarantee rotation accuracy.At present,most of the bearings are lubricated by oil or grease,which not only can reduce friction and resist wear,but also has rustproof effect.In the practical work,poor lubrication of the bearing often occurs in the course of work due to the operating temperature rising,the impact load and the differential sliding,etc.,therefore,in the design of oil-lubrication bearing,the properties of elastohydrodynamic friction based on the actual working state and antifriction have become the most important factors deciding the service lifetime and dynamic characteristics of the bearing.With the development of industry,a variety of new lubricants continue to appear,the basic formula and additives are also very different,the different lubricants exhibit different drag characteristics under different operating conditions,so the study to the drag characteristics of different lubricants is very important.In view of this,in this thesis,the test of elastohydrodynamic lubrication characteristics on the testing oil was carried out under different working conditions,which can provide theory reference and data support for research and development of high-performance bearings.After the improvement of the testing machine,the testing of elastohydrodynamic lubrication without considering the spin effect is used by planar disc was carried out,and the testing of elastohydrodynamic lubrication with considering the spin effect is used by cone disc was carried out too to study the effect of different spin angles.Through the analysis of the test results,the change law of the elastohydrodynamic friction coefficient changing along with sliding-rolling ratio,loads,involution velocity and oil temperature is summarized,while,the elastohydrodynamic lubrication under different spin angles and the EHL model apply to the lubricating oil were also discussed.The study shows that the change law of changing along with sliding-rolling ratio,loads,involution velocity and oil temperature is obvious,and the drag curve is consistent with the classical drag curve law.Under the effect of spin angle,the friction coefficient will increase,and with the increase of spin angle,the friction coefficient increases correspondingly.The test data of elastohydrodynamic lubrication without considering the spin effect was fitted by the exponential model with four parameters,it can be seen from the fitting results that the exponential model with four parameters can fit the elastohydrodynamic friction characteristics curve accurately within the whole test,suitable to predict the lubrication performance of the oil in engineering.Meanwhile the test data with considering the spin effect was fitted by T-J model,the results show that the fitting curve of T-J model is high different from the test results at low temperature,the T-J model is not suitable to fit the EHL curve with strong thermal effect.