DE 10 2009 051 574 A1 discloses a solenoid valve for controlling a fluid, comprising a first housing section with an axial guide for a solenoid armature. The solenoid armature is moveable in axial direction under the effect of a solenoid coil that surrounds the first housing section on the outside at least partially, with an energy storage device and with an actuator acting on a valve closing member. Due to the fact that in the known solution the valve closing member comprises a non-return valve for controlling a bypass bore in the valve closing member, the housing of the non-return valve holds a non-return valve closing member and keeps the closing member moveable, and is formed in one piece with the valve closing member. The housing, due to a form change after insertion of the non-return valve closing member, retains the non-return valve closing member in its respective functional position. A solenoid valve of this kind may be made more simply due to the above-described design of the non-return valve housing, in particular with respect to the required manufacturing tolerances.
The known solenoid valve solution comprises a main control stage and a pilot control stage that controls the main control stage. The pilot control stage can be operated via the armature that forms part of a magnet actuating system. Such solenoid valves or directional control valves are used essentially in fluid systems for controlling flow rates.
Pilot-operated directional control valves are particularly well suited for switching high pressures and high flow rates since the flow forces and the friction forces can be compensated for to a large extent. Overall, an excellent ratio of installation space to flow resistance is achieved when utilizing a pilot control stage for controlling the main control stage so that a high level of performance at a small installation space is achieved. Moreover, the switching time of the valves through the pilot control stage can be influenced. Pilot-operated directional control valves in poppet valve design are cost-effective and provide high hydraulic performance at the same time.
Pilot-operated directional control valves today are usually fitted with a pilot control stage, as described in DE 10 2009 051 574 A1, in order to achieve the required switching performance. The usual requirements are high pressure, for example, >350 bar and a high flow rate of, for example, >200 l/min at a pressure differential of approximately 5 bar. Particularly in instances where the application requires a very high dynamic performance, such as is required, for example, for emergency switching functions or for isolating switches, very high valve dynamics are required.
The above described and known solenoid valve solution is designed as a kind of screw-in cartridge valve for installation into an overall valve block. This solution may be then used advantageously and space-savingly in a modular valve design. The only disadvantage of the known solution is that it cannot meet the requirements for high switching performance and high valve dynamics.