Two valves control of hydraulic drive by way of inverted flow characteristic

Abstract

Paper deals with control of hydraulic drive by the help of inverted flow characteristics of hydraulic valves. One edge valves or two edges valves, theirs combinations and 3/3-way valves are able to control each chamber of cylinder separately as independent control action members. The case of two three-position three way valves can realize the same functions as a classical three position four-way valve to control hydraulic cylinder, but with an additional control degree of freedom, which could be in several cases profitable. Especially when user can use required criteria in form of required pressures ratio or flows ratio inside of cylinder chambers. In paper the control concept of inverted three-dimensional valves characteristic and inversed dynamic valve behaviour are described. Intended control concept allows transferring classical hydraulic circuit course and its unsymmetrical static characteristics of circuit realization with single piston rod of cylinder to a course of hydraulic circuit with double piston rod of cylinder.