Influence of the Contact Stiffness Between the Cam and the Roller in the Dynamic Behaviour of the Train Follower Applied in a Conjugate Cam Mechanism

Abstract

The aim of this study is to analyze the influence that the contact stiffness between the cam and the roller has in the prediction of the dynamic behaviour of the train follower. For this purpose two models based on the Hertzian contact theory are compared. The first model uses the formulation of the general contact assuming a nominal contact point between the cam and the roller. The second model uses the formulation of the cylindrical contact assuming a nominal contact line between them. The objective is to discuss about the convenience of both models when facing the calculations of the deviation from the theoretical motion law, contact forces, contact pressures, life span and surface fatigue in comparison with the surface finishing process for the cam or the roller. The study is set in a conjugate cam mechanism mounted in an automated process for manufacturing wirehoods. Results confirm the goodness of the general contact formulation applied when crowned rollers are used and the results dissuade the cylindrical contact formulation when rollers with cylindrical outer surface are used.