Influence of bearing ovalization in the dynamic of a planar slider-crank mechanism

The influence of geometric deviations in mechanism is frequently studied in order to predict its behavior and increase the overall predictability of the equipment. In this context, this work investigates the impact of bearing's ovalization in the dynamics of a planar slider-crank mechanism with a hydrodynamic bearing located between the connecting rod (conrod) and the crank. The mechanism's equations are obtained through Lagrange's equation and the hydrodynamic bearing's forces are evaluated by computationally solving Reynold's equation. The ovalization of the bearing is analyzed as being elliptical. The variables studied are the ellipticity, the ellipticity angle, the mean radial clearance and the bearing diameter. The parameters studied are the orbit of the journal inside the bearing and the non-dimensional minimum oil film thickness. Results indicate that the variable with most impact in the behavior of the orbit is the ellipticity angle and that the main responsible for changes in the non-dimensional minimum oil film thickness is the journal's radius. The results also show that an increase in the ellipticity only highlights the behavior that the ellipticity angle determines. It was also possible to determine the optimal ellipticity angle that improves the operation of the bearing without big changes in the mechanism.