Multibody Dynamic Simulation of CVJ Considering Friction Characteristics

초록

CVJ (Constant Velocity Joint) is the main component of a vehicle that transmits the driving force of an engine/transmission to a wheel at a constant speed. GAF (Generated Axial Force) is caused by internal friction in plunging-type CVJ. This force can have a direct impact on degradation of vehicle NVH characteristics. The typical vibration characteristic of CVJ to the vehicle is the shudder which deteriorates the lateral oscillation of the vehicle. The shudder is a phenomenon that the GAF generated by the rotation of the CVJ during the low-speed acceleration stimulates the transverse motion of the vehicle and gives the passenger an unpleasant feeling. Grease is used to reduce the friction between the roller and the housing of the CVJ. As the joint angle of the CVJ changes, the temperature of the grease changes, which affects the friction characteristics of the grease. The friction characteristics of grease have a significant influence on GAF. In this study, temperature dependent friction characteristics of grease according to joint angle is implemented in multibody dynamic simulation to improve the accuracy of the model. To experimentally measure GAF, the axial force measurement test is carried out with CVJ from C-segment. Also, the friction characteristics of the grease used in CVJ were confirmed by SRV friction test. The GAF results were obtained by applying the temperature dependent friction characteristics and axial test conditions to the multibody dynamic simulation in DAFUL. The simulation results are verified by comparing with the experiment results. The obtained results can be used to reduce the data errors of simulations and experiments and build accurate simulation models.