Study On Micro-texture Anti-wear Structure And Elastohydrodynamic Lubrication Characteristics Of Tripod Sliding Universal Joints

Tripod sliding universal joints was a new type of joints independently developed by Qingdao University of Science and Technology.It has the advantages of good synchronization performance and strong transmission capability.Firstly,the rigid-flexible joints dynamics analysis of the tripod sliding universal joints was carried out to determine the main wear position of the joints in the working process.After that,a textured anti-wear structure favorable for lubrication was proposed based on the surface micro-texture technology.The numerical calculation model of textured anti-wear structure was established,and the lubrication characteristics of elastohydrodynamic lubrication under isothermal and thermal conditions were analyzed.Finally,the experimental research was carried out.In the rigid-flexible joints dynamic analysis of the tripod sliding universal joints,the dynamic contact stress of the joints under actual working conditions was studied,and the influences of the input shaft torque(load),the axis angle(amplitude)and the rotation frequency(frequency)of the tripod sliding sleeve(input shaft)and the tripod sliding(output shaft)on the sliding rod were studied in depth.The dynamic equivalent contact stress distribution nephogram and the contact stress curve of the sliding rod were obtained,and the fatigue life of the sliding rod was predicted on this basis.According to this,the main wear position of the joints in the working process was determined,and a new anti-wear structure was proposed based on the surface micro-texturing technology,and a texturing mathematical calculation model was established.According to the established texturing mathematical calculation model,the grease lubrication characteristics were numerically analyzed under isothermal and thermal conditions respectively.The influences of the radius of annular bulge(equivalent radius),input shaft torque(load),angle(amplitude)between the tripod sliding sleeve(input shaft)and the tripod sliding(output shaft)and rotation frequency(frequency)on the pressure,oil film thickness and temperature rise were investigated under the conditions of untextured model and textured model.Under isothermal and thermal conditions,the increase of equivalent radius increases the thickness of lubricating oil film and decreases the pressure.The increase of included angle and frequency will increase the oil film thickness and the second pressure peak value.At the same time,the greater the load,the greater the contact pressure and the smaller the oil film thickness.Considering the temperature rise factor,the increase of equivalent radius will reduce the temperature rise in the contact area,but the increase of load,frequency and axis angle(amplitude)will increase the temperature rise in the contact area.At the same time,a reasonable width of the textured model crown region has certain beneficial effects on the lubrication of the contact area.When the conditions were met,the textured model can effectively increase the thickness of the lubricating oil film,reduce the pressure of the oil film and greatly improve the lubrication environment.However,an unreasonable width of the textured model crown region may have no effect or make the lubrication environment sharply harsh,result in a decrease in the thickness of the oil film and an increase in the pressure of the oil film.However,the texturing of the structure will increase the temperature rise in the contact area,which was not conducive to lubrication.The anti-wear structure based on surface micro-texturing technology was experimentally studied by using elastohydrodynamic lubrication film measuring instrument,and the established texturing mathematical calculation model was further verified by experiments,which proves the correctness of the established numerical calculation model,and concludes that the texturing model cannot improve the lubrication performance of two contact objects when the low-speed load was small,and has a certain inhibition effect on the formation of lubricating oil film,thus aggravating the wear.However,when the high-speed load was large,the texturing model that most reasonable crown width can effectively increase the thickness of the lubricating oil film,reduce the pressure of the oil film,and greatly improve the lubrication environment.