Rolling Ball Type Of Tripod Universal Joints And Its EHL Performance

The rolling ball type of tripod universal joints has the advantages of good cushioning and vibration reduction,low manufacturing cost,convenient processing and installation,large load bearing,and reliable operation.However,the contact force between the ball of this coupling and the three-column groove shell is large and the relative movement is frequent,which will cause serious friction and wear.In order to improve the friction and wear of the rolling ball type of tripod universal joints,this thesis investigates the kinematics and dynamic characteristics of the slider assembly of the rolling ball type of tripod universal joints,and on this basis,its lubricating characteristics for analysis.The main research contents are as follows:Kinematics and dynamics analysis of the slider assembly of the rolling ball type of tripod universal joints.First,establish a motion analysis coordinate system on the simplified geometric model of the coupling,use the direction cosine matrix to analyze the motion characteristics of the rolling ball type of tripod universal joints,and obtain the position and speed changes of the slider assembly during the operation of the coupling,and Explored the influence of different working condition parameters on the slider speed;Secondly,on the basis of kinematics research,the force analysis is carried out on the contact point of the trigeminal rod,the three-column groove shell and the slider assembly,and the change of each force at the slider assembly during the coupling operation is explored The influence of different working condition parameters on each force at the contact point is shown.Establish an isothermal point contact elastohydrodynamic lubrication model and explore the influence of different parameters on the lubrication characteristics.Based on the point contact geometric model,the lubrication analysis equation of the simplified geometric model under isothermal Newtonian fluid conditions is established,and the principle of the multi-grid method is used for calculation.The numerical algorithm isprogrammed by Fortran language to obtain a stable and complete numerical solution,and the calculation results of oil film thickness distribution and pressure distribution are obtained.Finally,the calculation results were processed by Origin drawing software to obtain a three-dimensional graph of the thickness and pressure distribution of the isothermal point contact elastohydrodynamic lubrication film.The effects of different radius of curvature,entrainment speed,viscosity,and load on oil film thickness and pressure distribution were also explored.Elastohydrodynamic lubrication characteristics of the rolling ball type of tripod universal joints under isothermal Newtonian fluid and the influence of different parameters on its lubrication characteristics.First,establish the elastohydrodynamic lubrication model of the ball and slider groove,and combine the kinematics and dynamic characteristics of the coupling ball and slider groove to perform the spring at the quarter of the cycle with the largest interaction force and the fastest relative speed Research on flow lubrication characteristics.In the calculation process,the multi-grid method is used to solve the Reynolds equation,the multi-grid integration method is used to solve the solid surface deformation,and the numerical algorithm is programmed by Fortran language to obtain the calculation results of the oil film thickness distribution and pressure distribution.The lubricating characteristics of the rolling ball type of tripod universal joints with different input frequency,three-pillar groove radius,shaft intersection angle,input torque,ball radius,lubricating oil viscosity and elastic modulus under the isothermal Newtonian fluid condition are analyzed influences.The effect of thermal effects on the lubrication characteristics of the rolling ball type of tripod universal joints.The isothermal assumption in the study of the coupling's elastohydrodynamic characteristics is only based on an assumption under ideal conditions,and is only applicable to low temperature,light load or excellent heat dissipation and other small temperature changes.When the coupling is in a high-speed,heavy-load and poor heat dissipation working environment,the influence of the thermal effect on the coupling cannot be ignored.Therefore,it is necessary to analyze the lubrication characteristics of the coupling under thermal effect.The lubrication analysis control equations under isothermal conditions are modified to obtain the lubrication analysis control equations considering thermal effects.The numerical algorithm is programmed by Fortran language to obtain the complete numerical solution of lubricating film thickness,pressure and temperature.And compare the film thickness and pressure of the lubricating oil film of the isothermal and thermal elastic flow under the same workingconditions.Furthermore,the effects of different input frequencies,three-pillar groove shell radius,shaft intersection angle,input torque,ball radius,lubricating oil viscosity and elastic modulus on the lubricating properties of the rolling ball type of tripod universal joints are investigated.