Mechanical Cushion Design Influence on Cylinder Dynamics

The paper deals with the simulation and the experimental verification of the dynamic behaviour of a linear actuator equipped with different configurations of mechanical cushion. A numerical model, developed and tailored to describe the influence of different modulation of the discharged flow-rate (and of the correspondent discharging orifice design) on the cushioning characteristics variation is firstly introduced. Then, with respect to the case of the cylindrical cushioning engagement, both the reliability and the limits of the numerical approach are highlighted through a numerical vs. experimental comparison, involving the piston velocity and the cylinder chambers pressure. After, with the aim of highlighting the effect of mechanical cushions design on a two effect linear actuator dynamic performances, the characteristics modulation of four alternative cushioning systems are determined and deeply analyzed. Finally, a sensitivity analysis about the influence of the variation of the main geometrical parameters is introduced and, thanks to the introduction of some dimensional and non-dimensional parameters of engineering interest, some useful guidelines in selecting the most effective cushion shape are highlighted.