PUB - Direct Actuation of Large Sized Valves by a Hydraulically Relieved Electromechanical Actuation System
Directional control valves are used to open or close flow paths of hydraulic systems. Valves can be distinguished in their design (spool or seat valve), their adjustment (switching or proportional) and their actuation system. To ensure the interchangeability of different valves the International Organization for Standardization has defined the dimensions and other specifics for mounting surfaces of four-port hydraulic directional control valves in the ISO 4401.
Authors: Vonderbank, Tobias; Laßl Chavez, Pierre Marc; Schmitz, Katharina
Extensive actuation forces and strokes are required for the actuation of large sized valves normally implemented in high power hydraulic systems. A hydraulically piloted operation is, for now, the most suitable solution and state of the art. However, there are some applications where electromechanical valve actuation systems are at advantage against common pilot operation systems. In this contribution it is analyzed in which cases the application of electro-mechanical actuators can be of advantage and why displacement-controlled systems may be one of these applications. A novel electromechanical valve actuation system for large sized 4/3-way directional control valves for the use in displacement-controlled systems is presented. This new actuation system is characterized by a hydraulic relief of the centering springs. Therefore, the springs are only active in safety-critical conditions, such as a power outage. Since the actuator is not working against the spring force during every displacement, the necessary actuation force is reduced drastically. Thus, common electromechanical actuators can be used.