Generated Axial Force Estimation Model of Tripod Type CV Joint Considering Friction Coefficient and Rolling-Sliding Ratio

Abstract

This study proposes a new Generated Axial Force (GAF) estimation model of tripod type Constant Velocity (CV) joints. In order to overcome weakness of the existing methods which didnt consider or simplified friction characteristics, this study consider the rolling-sliding ratio and the friction coefficient based on the experimental analysis. In the first step of the development of the model, kinematic analysis was performed to derive the relative coordinates of components and contact points. Through the analysis, the normal load that acts on contact points was also obtained. This study employs two friction characteristics – pure sliding friction characteristics and rolling-sliding friction characteristics – to obtain the friction coefficients on the contact points. Especially for rolling-sliding friction, this study used the experimental analysis on rolling-sliding ratio and then, friction coefficients were also studied by using a tribometer. By introducing two friction characteristics, this study considers not only the pure sliding friction but also the rolling-sliding friction that occurs between spherical rollers and tracks. This study verifies the GAF estimation model by comparing the simulation results with the experimental results. A tripod type CV joint was set as a target and its GAF was derived by the model. Then, its actual GAF was measured and the results were compared with each other. For the measurement, a GAF measurement system was set up in this study. The estimated results shows the similar tendency with the measured results at low resistance torque condition and furthermore, the GAF model provides very accurate estimation at high resistance torque conditions. By using the developed GAF model, GAF factors were analyzed. The influence of the GAF factors on the GAF was analyzed and then the influence on the GAF factors was verified through a GAF measurement system. New prototypes with the changed design parameters were manufactured and its GAF were measured. Based on the results, the optimized design parameters were selected and its GAF was also verified. As a final outcome of this study, GAF reduction was achieved.