Kinematic and Dynamic Evaluation of Lug Drive Track Mechanism Found on Electric Mining Shovels

The kinematics and dynamics of the engagement mechanism of track links with the drive sprocket particular to an electric mining shovel is not fully understood. Slight modifications in design of the engagement mechanism may have significant effects on durability of sprockets and tracks. Common construction vehicles utilize a track, which closely resemble an engineered roller chain and sprocket drive arrangement. The lug drive mechanism used on electric mining shovels is fundamentally different than that of a conventional roller chain. While the kinematics and dynamics of roller chains have been studied in a generalized manner, generalized kinematic and dynamic studies of the engagement mechanism of lug drive tracks are not in published literature. Several geometric factors influence the kinetics and dynamics of lug drive track systems. Friction at the sprocket, depth of sprocket engagement, and pressure angle influence loading on connecting pins and general performance of the system. Obtaining an understanding of the interaction of these design parameters is required. Once the interaction of these factors is defined, design improvements will be possible which will increase reliability, efficiency, and reduce product cost. Computer aided dynamic analysis of the contact and friction forces of multiple complex shaped bodies is difficult with current commercially available dynamic analysis codes. Modeling of static and dynamic friction are limited by the algorithms employed in current codes which are optimized for ease of numerical integration. This thesis will develop and compare the limitations of the contact and friction modeling employed by two dynamic codes: Working Model and DADS. The goal of this thesis is to develop guidelines for the interaction of several sprocket design parameters and to develop a user friendly methodology for analyzing the kinematics and dynamics of this type of drive system