Analysis of an Automotive Driveline with Cardan Universal Joints

A detailed methodology is presented in this paper for a complete assessment of various forces, torques, and kinematic effects due to universal joint angularities and shaft yoke phasing. A modular approach has been adopted wherein constitutive equations represent each of the key elements of a driveline namely the driveshaft, coupling shaft, universal joint, and the transmission/axle shafts. Concentrated loads are used wherever loads are being transferred between the elements of a driveline. Local matrices are developed for the equilibrium of the respective driveline members. The local matrices are then assembled into a global matrix and solved for the kinematic state of the complete driveline. A 6x15 matrix has been developed to represent a general shaft in the system and a 6x10 matrix has been developed for a universal joint cross. This gives us a complete picture of all the loads on all driveline members. The calculated bearing loads can then be used to appropriately design or select the trunnion and center bearings. The developed approach can accommodate angularity changes in three dimensions. Thus a very general algorithm has been developed to address driveline issues encountered in practice. Experimental studies have been conducted on a truck driveline and the vibratory response of the driveline was recorded. In addition, computer simulations have been undertaken to predict the vibratory response of the same driveline. Results from both the studies are presented in this paper.