Experimental Methods for Measuring the Viscous Friction Coefficient in Hydraulic Spool Valves

In hydraulic components, nonlinearities are responsible for critical behaviors that make it difficult to realize a reliable mathematical model numerical simulation. With particular reference spool valves, the viscous friction coefficient between sliding and fixed body is an unknown parameter normally set posteriori in order obtain good agreement with experimental data. this paper, two different methodologies characterize experimentally component presented. The approaches significantly both based on tests; they were developed distinct laboratories periods of time applied same flow compensator pump displacement control. One procedures was carried out at Fluid Power Research Laboratory Politecnico di Torino, while other approach University Parma. Both proposed methods reached similar outcomes; moreover, neither method requires installation transducer can affect results.