Valve Control Concepts in a Constant Pressure System with an Intermediate Pressure Line
- Quelle: The 21th International Conference on Hydraulics and Pneumatics,1-3 June 2011, Ostrava, Czech Republic
The paper presents a new hydraulic system based on constant pressure with the aim of increasing the efficiency of working hydraulics in mobile machines. The system consists of a high pressure line at constant pressure, a tank pressure line and an additional line with intermediate pressure. Each actuator is supplied by a valve block consisting of two 3/2- switching valves and one proportional valve. The switching valves connect the inlet and the outlet port of the proportional valve to one of the three available pressure levels tank-, intermediate-, and high-pressure and allow five different pressure potentials. The proportional valve enables the fine control of the actuator and a constant, load adapted flow. The paper describes furthermore by the use of a simulation model the dynamic effects on the movement of the actuator when the switching valves are actuated or oscillating loads are applied. Control concepts for a smooth movement of the hydraulic cylinder at different load cases are shown and discussed concerning their capability for the hydraulic system.