Redundant electrohydraulic valve system
An electrohydraulic valve assembly having an inflow channel, a working channel and an outflow channel, including first and second valves each having a magnetic regulating device for applying a regulated activation force to the respective valve. The valves are arranged in parallel so that either can provide the hydraulic connection between the inflow, working and outflow channels. In the case of error detection, the active valve is deactivated and the until then passive valve is activated and vice-versa. The deactivating of a valve device moves the valve piston to a hydraulic neutral position by means of a second stage.
1. An electrohydraulic valve assembly, comprising:
an inflow channel P, a working channel A and an outflow channel T;
a first valve device having a first valve piston, a first control installation, and a first magnetic regulating device for applying a regulated activation force to the first valve piston;
a second valve device having a second valve piston, a second control installation, and a second magnetic regulating device for applying a regulated activation force to the second valve piston;
wherein the first and the second valve devices are arranged in parallel to each other, so that by means of a positioning of the first valve piston and/or the second valve piston a hydraulic connection between the inflow channel P and the working channel A and/or the working channel A and the outflow channel T can be created, or such a connection can be closed;
wherein in operation either the first valve device or the second valve device is active and satisfies the function of the electrohydraulic valve assembly, the respective other valve device being passive;
wherein in case the control installation of the until then active valve device detects an error, it activates the until then passive valve device and deactivates itself;
wherein in case the control installation of the until then passive valve device detects an error, it activates itself and deactivates the until then active valve device;
wherein the deactivating of one of said valve devices comprises a valve piston of the respective valve device moving to a hydraulic neutral position by means of a second stage for each of the first and second valve devices, wherein the second stage comprises an actuating element for moving the valve piston, wherein each said actuating element is separate from the first and second respective magnetic regulating devices.
2. The electrohydraulic valve assembly according to claim 1 , wherein the first and/or the second magnetic regulating device comprises a regulating magnet to which a nominal force value for the activation force of the valve piston is predetermined.
3. The electrohydraulic valve assembly according to claim 2 , wherein the first valve device and/or the second valve device comprises a control magnet, which moves the valve piston to the hydraulic neutral when activated.
4. The electrohydraulic valve assembly according to claim 2 , wherein the electrohydraulic valve assembly regulates the volume stream for at least one corresponding working cylinder, and to the first valve device and/or to the second valve device a position regulating means is assigned, which by means of the regulating of the volume flow regulates the position of the working cylinder.
5. The electrohydraulic valve assembly according to claim 4 , wherein the position regulating means comprises an underlaying feedback loop for regulating the activation force of the valve piston.
6. The electrohydraulic valve assembly according to claim 1 , wherein a first and/or a second control installation error detecting means are assigned, wherein the error detecting means comprise a nominal value monitoring and/or a monitoring of the speed of change of the nominal value and/or an actual value monitoring with respect to extreme values and/or a two-step control having a regulation frequency monitoring.
7. The electrohydraulic valve assembly according to claim 1 , wherein the first valve device and/or the second valve device are designed as proportional directional valve(s).
8. The electrohydraulic valve assembly according to claim 1 , wherein the first valve device and/or the second valve device is a 3/3 valve device or a 4/3 valve device.
9. The electrohydraulic valve assembly according to claim 1 , wherein the inflow channel P is throttled.
10. The electrohydraulic valve assembly according to claim 9 , wherein the inflow channel P has a smaller cross section than the outflow channel T.
11. The electrohydraulic valve assembly according to claim 9 , wherein the inflow channel P comprises an aperture.
12. The electrohydraulic valve assembly according to claim 3 , wherein the electrohydraulic valve assembly regulates the volume stream for at least one corresponding working cylinder, and to the first valve device and/or to the second valve device a position regulating means is assigned, which by means of the regulating of the volume flow regulates the position of the working cylinder.
13. The electrohydraulic valve assembly according to claim 2 , wherein a first and/or a second control installation error detecting means are assigned, wherein the error detecting means comprise a nominal value monitoring and/or a monitoring of the speed of change of the nominal value and/or an actual value monitoring with respect to extreme values and/or a two-step control having a regulation frequency monitoring.
14. The electrohydraulic valve assembly according to claim 3 , wherein a first and/or a second control installation error detecting means are assigned, wherein the error detecting means comprise a nominal value monitoring and/or a monitoring of the speed of change of the nominal value and/or an actual value monitoring with respect to extreme values and/or a two-step control having a regulation frequency monitoring.
15. The electrohydraulic valve assembly according to claim 4 , wherein a first and/or a second control installation error detecting means are assigned, wherein the error detecting means comprise a nominal value monitoring and/or a monitoring of the speed of change of the nominal value and/or an actual value monitoring with respect to extreme values and/or a two-step control having a regulation frequency monitoring.
16. The electrohydraulic valve assembly according to claim 5 , wherein a first and/or a second control installation error detecting means are assigned, wherein the error detecting means comprise a nominal value monitoring and/or a monitoring of the speed of change of the nominal value and/or an actual value monitoring with respect to extreme values and/or a two-step control having a regulation frequency monitoring.
17. The electrohydraulic valve assembly according to claim 2 , wherein the first valve device and/or the second valve device are designed as proportional directional valve(s).
18. The electrohydraulic valve assembly according to claim 3 , wherein the first valve device and/or the second valve device are designed as proportional directional valve(s).
19. The electrohydraulic valve assembly according to claim 4 , wherein the first valve device and/or the second valve device are designed as proportional directional valve(s).
20. The electrohydraulic valve assembly according to claim 5 , wherein the first valve device and/or the second valve device are designed as proportional directional valve(s).
21. The electrohydraulic valve assembly of claim 1 , wherein the second stage actuating elements comprise control magnets.