Mechanical Cushion Design Influence on Cylinder Dynamics

The paper deals with the simulation and theexperimental verification of the dynamic behaviour of alinear actuator equipped with different configurations ofmechanical cushion. A numerical model, developedand tailored to describe the influence of differentmodulation of the discharged flow-rate (and of thecorrespondent discharging orifice design) on thecushioning characteristics variation is firstlyintroduced. Then, with respect to the case of thecylindrical cushioning engagement, both the reliabilityand the limits of the numerical approach arehighlighted through a numerical vs. experimentalcomparison, involving the piston velocity and thecylinder chambers pressure. After, with the aim ofhighlighting the effect of mechanical cushions designon a two effect linear actuator dynamic performances,the characteristics modulation of four alternativecushioning systems are determined and deeplyanalyzed. Finally, a sensitivity analysis about theinfluence of the variation of the main geometricalparameters is introduced and, thanks to theintroduction of some dimensional and non-dimensionalparameters of engineering interest, some usefulguidelines in selecting the most effective cushionshape are highlighted.