Energies, Vol. 10, Pages 746: Experimental Study of 3D Movement in Cushioning of Hydraulic Cylinder (Energies)

A double acting cylinder operation has been fully monitored in its key functional parameters, focused on characterization of end-of-stroke cushioning and starting phases. Being the cylinder performance reliant in the piston constructive geometry, the number and location of piston circumferential grooves is a significant parameter affecting the internal cushioning system performance. An eddy current displacement sensor assembled in the piston allows assessment of piston radial displacement inside the cylinder tube, which is directly related with the studied operating phases. Due to such 3D displacements, the piston becomes as an active and self-adjusting element along the functional cycle of the cylinder. Mechanical joints orientation and operating pressure are also relevant parameters affecting piston radial displacement and, thus, the cushioning and starting performance. Computational Fluid Dynamics (CFD) results confirm the observed functional role of the perimeter grooves; the flow and pressure distributions, where develops a significant radial force, are also in accordance with the registered radial displacement.