Secondary Torque in Automotive Drive Shaft Ball Joints: Influence of Geometry and Friction

Abstract

Automotive drive shafts are made of two constant velocity joints coupled by an intermediate shaft. In general, the joint close to the gearbox is a plunging tripod joint, the movement of which serves suspension. The joint close to the wheel is a fixed ball type joint, which allows the steering movement. The article is devoted to secondary torque generated by the ball joint during torque transmission. This study is based on an ADAMS model in rigid bodies with local deformation at contact (Hertz theory) and on industrial test bench measurements. After geometrical representation of ball joint kinematics and before the secondary torque calculation, the ADAMS model is validated through the calculation of internal efforts, which are compared with the models and measurements already presented in the literature. Concerning the secondary torque study, measurements with an industrial test bench at the NTN TE Test Department and the ADAMS model show that the R6 component of the secondary torque (orthogonal to the joint plane) is found to be negligible with respect to the transmitted torque (<2 N m for 300 N m input torque). The results of the ADAMS model also show that the steering component of the secondary torque (in the joint plane and orthogonal to the wheel axis) does not only depend on the joint angle but also on the friction and sign of the transmitted power.