The Force And Simulation Analysis Of Tripod Universal Joint

Tripod universal joint is one of the most important universal joints inthe sliding side of the shaft assembly. When the car steering or when theroad uneven, the roller will have axial sliding along the groove, which cancompensate for changes in the axial direction of the shaft length. But in thecourse of transmission, the pressure and friction between the componentsis inevitable. Thus, it will produce axial movement, which will directlyaffect the vibration and noise when car driving and also affect theperformance and service life of the drive shaft assembly. Therefore, thestudy of tripod joint’s kinematic performance, the contact force andinternal friction and its variation is necessary.Firstly, based on the spatial structure and motion model of tripod joint,use the coordinate transformation method, analyze the main geometricparameters and motion parameters under constant and non-constantcircumstances. Calculate the analytical formula of eccentricity and ballring radius under constant conditions. Under non-constant conditions,analyze the change rule of the swing angle, eccentricity e, the differencebetween the input angle and output angle, the motion curve of the center oftripod.Secondly, analyze the contact force and friction of the roller. Usingthe analytical method analyze the variation of contact force with the swingangle and rotating angle. And also analyze the friction between roller andgroove when the roller sliding in and sliding out along the groove. Thefriction generates the axial force and radial force. Through the graphicalvisualization capabilities of Matlab, analyze the change role of axial force and radial force.Thirdly, establish the parameterized geometry model in theSolidworks, then import it into the Adams to establish the multi-bodydynamics model with a clearance. In order to describe the motion of tripodjoint more reality, the contact force uses nonlinear equivalentspring-damper model, the friction uses corrected Coulomb friction model.Finally, based on the multi-body dynamics model with a clearance oftripod joint in the Adams, some tests was made including constant speedtest, the output angle speed test, the position of the center of tripod androller test, normal contact force test, axial force test, deflection torque testand the vibration test.The results showed that: tripod universal joint is essentially a non-constant velocity joints, swing angle cyclical variation with angle, theeccentricity, the difference of the input and the output angle is also cyclicalchanged. Its change period is2/3π, which is related with the distributionof rollers on the tripod plane. The friction between roller and groove is oneof the most important reasons of the axial endplay in tripod joint. Thefriction between roller and trunnion is the main reason of the radial forceand deflection torque, and the vibration of the axis direction is greater thanthe vibration of the radial direction. Reduce friction coefficient, reduceswing angle will be help to reduce axial force, reduce radial force. Thosewill help to reduce the vibration and noise of the tripod joint when carturning, starting and braking.