WO2019072728A1

WO2019072728A1 - Electrohydraulic system having an adjustment apparatus for a valve

Info

Publication number: WO2019072728A1
Application number: PCT/EP2018/077247
Authority: WO
Inventors: Alexandre ORTH; Gottfried Hendrix
Original assignee: Robert Bosch Gmbh
Priority date: 2017-10-12
Filing date: 2018-10-08
Publication date: 2019-04-18
Also published as: DE102017218200A1

Abstract

The invention relates to an electrohydraulic system having an adjustment apparatus (1) for a valve (2), having a drive device (3), an actuating device (4) and a pre-tensioning device (5), wherein, in the event of a malfunction, the energy stored in the pre-tensioning device (5) can be transferred to the actuating device (4) such that a rotational movement of the actuating device (4) occurs which leads to the valve (2) being adjusted.

Description

Electro-hydraulic system with an adjusting device for a valve

The invention relates to an electrohydraulic system with an adjusting device for a valve, with a drive device, with an adjusting device and with a pretensioning device, wherein the energy stored in the pretensioning device can be transmitted to the actuating device in the event of a fault, so that a rotary movement of the actuating device is used.

Such electro-hydraulic systems with process valves can be used in a variety of industrial applications, eg. B. under water (offshore oil and gas) and also over water (on shore oil and gas). Such types of electrohydraulic systems are used, above all, to move an element underwater in water depths of up to several thousand meters in connection with the extraction of oil and natural gas, with mining, scientific investigations or infrastructure projects. So are z. B. in oil or natural gas production facilities at sea at great depths process valves with which the flow of the medium to be pumped can be controlled or shut off.

In a known device, the adjusting device is designed with an actuator for actuating a valve by means of an actuator. This actuator is associated with an emergency operating device, via which the actuator can be reset in a disturbance substantially independently of the actuation of the actuator. This emergency operating device has an energy store whose stored energy can be released for re-dividing. In this case, the emergency operating device has a piston which is acted upon on the one hand by the energy store and on the other hand by a pressure in a pressure chamber, which can be connected via a switching valve to a tank or the like in order to release the energy stored in the energy store. The piston is like this designed, that it displaces the actuator in a release of the pressure chamber in the return direction. The linear displacement of the piston in an emergency is transformed by a linearly displaceable driver in a likewise linear movement of the actuator (console), via which the valve is closed. To close a rotatably actuated valve, the linear displacement device is neither intended nor suitable. In particular, it disturbs that with the linear movement an immediate transmission of torque to the valve is not possible.

On this basis, it is an object of the present invention to provide an electro-hydraulic system with an adjusting device, which alleviates or even avoids the disadvantages mentioned. In particular, a compact design, namely a small space and an increased life should be realized in a structurally simple manner. In addition, an effective adjustment of the actuator is to be made possible in a simple way.

These objects are achieved with an arrangement according to independent claim 1. Further embodiments of the invention are specified in the dependent claims. It should be noted that the description, in particular in conjunction with the figures, further details and developments of the invention, which can be combined with the features of the claims.

An electrohydraulic system with an adjusting device for a valve, with a drive device, with an adjusting device and a pretensioning device contributes to this, wherein the energy stored in the pretensioning device can be transmitted to the setting device in the event of a fault, so that a rotational movement of the adjusting device is used Adjustment of the valve leads.

The electrohydraulic system presented here comprises an encapsulated emergency drive with a hydraulic energy store. Via a mechanical spindle or a hydraulic motor, the energy stored in a spring is converted into a rotary motion. In both cases, the spring is held taut by a hydraulic cylinder, which is shut off via a valve. When opening the valve, the cylinder is pushed by the spring and the energy is released. The rotational movement leads to immediate in case of failure Adjustment and thus for the rapid closure of a rotary actuated valve. The triggering of the adjusting device is fast and failsafe.

With the present device, an emergency safety module for rotary axles, in particular process valves, is provided without using electric batteries. The module is interchangeable with water and allows actuation of the valve by an external actuator or robot.

For multiple applications under water and also on water (onshore oil and gas), a rotatably actuatable actuator is preferred, which can be replaced with a standard interface (eg by an ROV). With the electrohydraulic system presented herein, a fault locking and locking mechanism for rotary actuators is realized using a spring system and a hydraulic control (without electric batteries) that is provided by an external actuator or underwater robot or vehicle (eg, ROVs and AUVs). can be exchanged and operated.

The fail safe mechanism for rotary actuated valves does not use batteries, but uses springs with reliable hydraulic control that can also be exchanged underwater, which have a spindle drive or a hydraulic motor and can also contain a complete drive system (ie not only safety functions, but also normal company work).

The adjusting device presented here implements a failure safety device with a spring system, the safety control system being integrated in a hydraulic control, i. H. An electric drive device is decoupled and a required torque and a rotational movement are provided to bring a process valve in a secured (closed) position and to hold in this position.

The emergency safety module for rotary operated process valves provides a high level of safety and reliability for a long service life (eg 25 years). It can be used as an independent module, either to supplement existing electrical actuators or as a single actuator. The module can easily be exchanged under water; the operation of an external tool or actuator can be disabled by an electro-hydraulic control system (no block). The actuator for the adjustment device may be a Remote Operated Vehicle (ROV) or an Autonomous Underwater Vehicle (AUV) or robot. When adjusting preferably come a threaded spindle or a hydraulic motor with rotary output into consideration. Preferably, the adjusting device is adapted to drive the valve rotatively, for. B. a process valve [?].

The valves may preferably be shut-off valves for blocking and opening a pipe. As valve elements are further preferably used hydraulically via hydraulic motor or mechanically adjustable via threaded spindle cone seat elements. The closing force generated by the counter-pressure causes an elastic deformation of the seat element. With sufficient closing force a leakage-free tightness is guaranteed. In this case, a valve cone is pressed by a movement spindle to a housing seat. The threaded nut can lie in the housing. The drive of the movement spindle is preferably via an actuator which performs a rotational movement. The movement spindle with the valve cone is linearly displaced during opening and closing of the valve, while the threaded nut remains stationary. It is also possible to use ball elements with a through bore, which are mounted in a seal and, when rotated by 90 °, release or shut off the opening. The ball element and the actuator are stationary. Further preferred are rotary valves are used.

The biasing means comprises a spring element, for. B. helical compression spring, plate spring, coil spring or another resilient element. The biasing means cooperates with a piston defining a liquid-filled pressure chamber, which is adapted to adjust the actuator at a relief of the pressure chamber in the return direction (closing direction) of the valve.

Preferably, the adjusting axis of the adjusting device and the adjusting axis of the valve are arranged coaxially with each other.

Preferably, the adjusting device comprises at least one mechanical threaded spindle and a spindle nut.

Advantageously, the adjusting device comprises at least one rotary hydraulic motor. Suitably, the biasing means comprises at least one spring system with at least one biasing spring, which is biased by at least one hydraulic cylinder with at least one pressure piston and at least one pressure chamber. Preferably, the pressure chamber is connected to at least one channel with at least one switching valve, at the opening of the hydraulic cylinder is displaceable by the spring system.

Preferably, the drive device for the setting device comprises an electric machine for a rotary drive of an external actuator or robot or a remote-controlled submerged-line washer.

Advantageously, a separating clutch is present between the drive device for the adjusting device and the adjusting device.

Suitably, the drive means for the actuator is connected to a hydraulic machine which is connected to the hydraulic cylinder.

Preferably, a freewheel is provided between the drive means for the actuator and the actuator.

The invention and the technical environment will be explained in more detail with reference to figures. The same components are identified by the same reference numerals. The illustrations are schematic and not intended to illustrate size relationships. The explanations given with reference to individual details of a figure are extractable and freely combinable with facts from other figures or the above description, unless it is absolutely necessary for a person skilled in the art or such a combination is explicitly prohibited here. They show schematically:

Fig. La: a side view of the adjusting device with the valve open and strained

Biasing means 1 with a closed valve and a relaxed biasing device, an embodiment with a lid on the cylinder housing and a relaxed biasing spring for a closed valve, the embodiment of FIG. 2 with tensioned biasing springs for an open valve, an embodiment without a lid and tensioned biasing springs for a open valve, the embodiment of FIG. 4 with tensioned biasing springs for a valve position between open and closed, the adjusting device with relaxed biasing spring and spindle nut in two positions and additionally shown with dashed lines shifted spindle nut, the adjusting device of FIG. Lb, but in addition with a separating clutch between the drive device and threaded spindle, an embodiment of the adjusting device with externally driven hydraulic pump and threaded spindle, an embodiment of the adjusting device with hydraulic pump and anget grated hydraulic motor, an embodiment of the adjusting device with hydraulically driven hydraulic motor and externally driven hydraulic pump, an embodiment of the adjusting device with hydraulic motor and hydraulic freewheel and 12 shows an embodiment of the adjusting device with a separating clutch between the drive device and the hydraulic motor.

1a and 1b show the adjusting device 1 with the valve 2 open and the tensioned first pretensioning spring 16.1 (FIG. 1a) and with the valve 2 closed and the first pretensioning spring 16.1 relaxed (FIG. 1b).

Shown is the adjustment device 1 for a valve 2 with a drive device 3, with an adjusting device 4 and with a biasing device fifth

The function diagrams of FIGS. La and lb show the adjusting device 4 for actuating a valve 2, z. B. a process valve via which a flow 6 is adjustable. The adjusting device 4 has a spindle drive with a drive device 3, z. B. a first electric machine 7, which drives a threaded spindle 8, which in turn meshes with a spindle nut 9. The spindle nut 9 is rotatably, but axially adjustable in the direction of arrows A and B guided on the threaded spindle 8, so that upon rotation of the threaded spindle 8 about the longitudinal axis 10 in the direction of arrows C or D, the spindle nut 9 is a linear feed in the direction of the arrows A and B performs. The rotational movement of the threaded spindle 8 is transmitted in the example shown to a ball element 11 of the valve 2 with a through bore 12 which is mounted sealingly in a valve housing 13. Through the valve housing 13, a valve passage 14 passes, which is continued at its mouths through tubes 15 and in which a gaseous or liquid medium (volume flow 6) flows. In the valve housing 13, a cavity is formed in which the ball member 11 is rotatably mounted with the bore 12 (flow opening). The ball element 11 is coaxially attached to the output end 8.2 (see FIG. 2) of the threaded spindle 8. In the state of FIG. 1a, the bore 12 and the valve channel 14 are aligned with each other; the full flow opening is released, so valve 2 is open. Upon rotation of the ball member 11 in the direction of arrow C (see Fig. Lb) or D by 90 ° cover the ball member 11 and the valve channel 14 each other, the passage is blocked, the valve 2 is closed. The electric machine 7 is arranged at the drive end 8.1 (see FIG. 2) of the threaded spindle 8. By controlling the electric machine 7 in normal operation can - via the rotational movement of the drive shaft 42 (see Fig. 7) of the electric machine 7 in the direction of arrows E and F, the rotational movement of the threaded spindle 8 in the direction of arrows C and D and the rotational movement of the drive shaft 56th (see Fig. 7) of the valve 2 in the direction of arrows R and S - the ball member 11 of the valve 2 in response to the rotational movement of the threaded spindle 8 in the direction of arrows C and B are adjusted.

In the case in which the valve 2 is opened (opened) and thus a certain volume flow 6 is set, the valve 2 would remain open in the event of a power failure or system-side fault, so that the function of the process fitting can no longer be controlled. For such a fault an emergency operating device is provided, by means of which the threaded spindle 8 can be returned to a basic position in which the valve 2 is closed (FIG. 1b). In the solution shown in Figs. La and lb this provision is done mechanically, with the emergency function no components must be electrically operated. The emergency operating device consists essentially of an energy storage, in the present case from the biasing device 5 with a first biasing spring 16.1 (spring accumulator), which is biased by a first piston 17.1. This first piston 17.1 defines with its one end region a first pressure chamber 18.1 with pressurized fluid of a hydraulic cylinder 19 (actuating cylinder). The other end region of the first piston 17.1 projects out of the hydraulic cylinder 19 and is in direct contact with the spindle nut 9 (pressure).

The first pressure chamber 18.1 is connected via a first channel 20 with a first electrically operable first switching valve 21 and a second switching valve 22, which are designed as a seat valve. These are biased by a first and a second spring 23 and 24 in their open position and can be adjusted by energizing a first or second solenoid 25 and 26 in their closed position. At 28, a first check valve is designated.

In the regular operation according to FIG. 1 a, the adjustment of the valve 2 takes place solely via the spindle drive by controlling the first electric machine 7 (electric spindle motor). The function of the switching valves 21, 22 will be explained below using the example of the first switching valve 21. In this case, the first solenoid 25 of the switching valve 21 is energized, so this is adjusted in its leak-free switching position. The spring accumulator of the biasing device 5 is charged, as in the first pressure chamber 18.1 a pressure is applied, which is sufficient to hold the spring accumulator in its biased position. The pressure medium is clamped via the switching valve 21.

In the event of a power failure or malfunction according to FIG. 1b, the spindle drive assumes an undefined position. In such an emergency, therefore, the first solenoid 25 is de-energized, so that the switching valve 21 is adjusted by the spring 23 in its open position. As a result, pressure medium can flow out of the first pressure chamber 18.1 via the open switching valve 21. As a result, the pressure in the first pressure chamber 18.1 is reduced. In this case, the first piston 17.1 in the direction H is adjusted by the force of the spring accumulator of the biasing device 5 and its movement in the direction I, so that pressure medium from the first pressure chamber 18.1 via the first channel 20, the open switching valves 21, 22 and the second channel 27th is ejected. The first pressure piston 17.1 is connected to the spindle nut 9 of the spindle drive, so that correspondingly executed with no self-locking gear spindle nut 9 is adjusted in the axial direction E, while the threaded spindle 8 is set in a rotational movement in the direction C. By rotary movement of the threaded spindle 8, the valve 2 is closed. As shown in Fig. La, the first electric machine 7, z. B. The hydraulic cylinder 19 sucks in oil and the first switching valve 21 and the second switching valve 22 (safety valves) block the return of the first biasing spring 16.1 as long as electric current the coils of the first switching magnet 25 and the second switching magnet 26 is located.

The valve 2, z. B. process valve, closes on the first biasing spring 16.1 (Fig. Lb) or via the drive of the threaded spindle 8 by the first electric machine 7 (Fig. La) with safety valves. In all embodiments, more than one or more threaded spindles 8, hydraulic cylinders 19 (impression cylinders) and / or biasing springs 16 may be used, in particular until the required torque is achieved. Figs. 2 to 5 show embodiments in which the longitudinal axis 10 of the threaded spindle 8, the spindle nut 9 and the cylinder housing 30 are arranged coaxially with each other. Likewise, preferably, the longitudinal axes of the adjusting device 4 (drive shaft 42) of the electric machine 7, the threaded spindle 8, the spindle nut 9) and the drive shaft 56 of the valve 2 are arranged coaxially with each other. The second biasing spring 16.2 and the third biasing spring 16.3 are each supported at one end on the cylinder housing 30. There are in each case a first pressure piston 17.1 and a second pressure piston 17.2 present. According to FIG. 2, the threaded spindle 8 has a drive end 8.1 and an output end 8.2. At the drive end 8.1, a ROV (not shown) with an electric machine 7 (see Fig. La, lb) be connected (drive from the outside). The threaded spindle 8 can also be driven by a first hydraulic machine 36 (hydraulic pump) in cooperation with a (not shown) hydraulic motor. To the output end 8.2, a valve 2 (see Fig. La, lb) may be connected. In the illustrated position of FIG. 2, the valve 2, z. B. process valve, closed (see Fig. Lb) and the second biasing spring 16.2 and the third biasing spring 16.3 are relaxed (not locked). The first switching valve 21 is open. A pressure fluid flow 38 flows out of the first pressure chamber 18.1 and the second pressure chamber 18.2. The cylinder housing 30 is in the direction K and thereby also the spindle nut 9 is displaced in the direction L, so that the threaded spindle 8 is rotated about its longitudinal axis 10 in the direction C (see Fig. Lb). The cylinder housing 30 has a first cover 34 on the side of the drive end 8.1 and a second cover 35 on the side of the output end 8.2. With a housing 29, 31 is a pressure compensation, 32 denotes a first spindle bearing and 33 a second spindle bearing. The first hydraulic machine 36 (hydraulic pump) is driven by an electric motor 37. The hydraulic drive from hydraulic machine 36 (hydraulic pump) and electric motor 37 can be installed as an auxiliary hydraulic drive, except for driving the threaded spindle 8 and / or the valve 2, in order to keep the first pressure piston 17.1 and the second pressure piston 17.2 pressurized (leakage oil loss). ,

However, in the illustrated position, the valve 2 is open (see Fig. La) and the second biasing spring 16.2 and the third biasing spring 16.3 are tensioned (locked). The first switching valve 21 is closed. In a step (not shown), pressurized fluid has previously been used fed into the first pressure chamber 18.1 and in the second pressure chamber 18.2, whereby the cylinder housing 30 in the direction M and thereby the spindle nut 9 have been moved in the direction N. In the embodiment shown in Fig. 4, the valve 2 is open (see Fig. La) and the second biasing spring 16.2 and the third biasing spring 16.3 are tensioned (locked). The first switching valve 21 is closed. The cylinder housing 30 is open at the top, that is, it has on the side of the drive end 8.1 no lid. The threaded spindle 8 can be rotated without having to re-tension the second pretensioning spring 16.2 and the third pretensioning spring 16.3.

The embodiment shown in Fig. 5 corresponds to the embodiment of Fig. 4. However, in the illustrated position, the valve 2 is in an intermediate position between open (see Fig. La) and closed (see Fig. Lb). The second biasing spring 16.2 and the third biasing spring 16.3 are cocked (locked). The first switching valve 21 is closed. A first pressure interspace 39.1 and a second pressure interspace 39.2 are filled with pressurized fluid. As a result, the spindle nut 9 is displaced in the direction O, so that the threaded spindle 8 is rotated about its longitudinal axis 10 in the direction C (see FIG. 1b). 6, the adjusting device 1 with a relaxed pretensioning spring 16.4 and the spindle nut 9 are shown in a first position 9 'and the spindle nut 9 is shown in dashed lines in a second position 9 " The biasing spring 16.4 is in pressure contact with the carrier element 40. The directions of displacement of the spindle nut 9 in normal operation are indicated by arrows A and B. The drive of the threaded spindle 8 takes place, for example, by the first electric machine 7 and the rotational movement in directions C and D, whereby the valve 2 is opened (Figure la) or closed (Figure lb)., The arrow P indicates the direction of displacement of the spindle nut 9 in position 9 ", whereby the biasing spring 16.4, z. B. compression spring, is stretched. The threaded spindle 8 is decoupled from the first pressure piston 17.1 in the direction of opening the valve 2. The pressure piston 17.1 and the spindle nut 9 are freely movable parts. The valve 2 can by the first electric machine 7, z. B. as part of the ROV, or the first switching valve 21 and the second switching valve 22 (safety valves) are locked. Fig. 7 shows the adjusting device according to Fig. Lb, but with an additional separating clutch 41 between the drive means 3 and the threaded spindle 8 (adjusting spindle). There is a separating clutch 41 for the drive shaft 42 of the first electric machine 7. As a result, there is a safety function (closing of the valve 2) even when coupled first electric machine 7 (ROV or drive). One advantage is that the first electric machine 7 (ROV or drive) can no longer block / prevent the safety function. At 54, a line from the separating clutch 41 to the second channel 27 is designated. 56, the drive axis of the valve 2 is designated. In Fig. 8 is an embodiment of the adjusting device 1 with an externally driven by a second electric machine 43 hydraulic machine 36, z. B. hydraulic pump, shown, which drives the hydraulic cylinder 19. The threaded spindle 8 (see FIG. 1b) is used here only for the translation of the linear movement (arrows E and I) into the rotary movement (arrow C). One advantage is that the power transmission from the second electric machine 43 (ROV or drive) is very easy to implement. It can be used a flexible bearing drive shaft.

According to Fig. 9 is an embodiment of the adjusting device 1 with a hydraulic machine 36, z. B. hydraulic pump, and an externally driven first hydraulic motor 44. The internal first hydraulic machine 36, z. B. hydraulic pump is driven by an electric motor 37. The first hydraulic machine 36 can operate either as a full drive or as a "refresh" (mini-drive, redundant function - for opening) .The threaded spindle 8 (FIG. 1b) is replaced by the first hydraulic motor 44 and can therefore also be directly from the external first In this case, a coupling 41 (see Fig. 7) may be present between the first electric machine 7 and the first hydraulic motor 44. The second biasing spring 16.2 acts on the first pressure piston 17.1.

10, an embodiment of the adjusting device 1 with a hydraulically driven first hydraulic motor 44 and externally driven second hydraulic machine 45, z. B. hydraulic pump shown. The first hydraulic motor 44 is driven externally by the first electric machine 7 via the second hydraulic machine 45. The hydraulic output of the second hydraulic machine 45 forms the hydraulic drive for the first hydraulic motor 44 (the transmission ratio is thus very flexible). It is a hydraulic circuit the second hydraulic machine 45 and the first hydraulic motor 44 available. With 46 is a third switching valve, with 47 is a fourth switching valve, with 48 is a second check valve and 49 is a third check valve. The second biasing spring 16.2 acts on the first pressure piston 17.1.

According to Fig. 11, an embodiment of the adjusting device 1 with a first hydraulic motor 44 and a hydraulic freewheel 50 is shown. In this case, the external first electric machine 7 (ROV or drive) can be decoupled by the hydraulic freewheel 50, that is to say in the event of an accident safety the electric machine 7 (ROV or drive) is switched off. The hydraulic freewheel 50 forms a hydraulic circuit of the second hydraulic machine 45 and a second hydraulic motor 51. In the hydraulic circuit 50, a fifth switching valve 52 and a sixth switching valve 53 are integrated. The second biasing spring 16.2 acts on the first pressure piston 17.1. According to FIG. 12, an embodiment of the adjusting device 1 with a separating clutch 41 between the external first electric machine 7 (ROV or drive) and the hydraulically driven first hydraulic motor 44 is present. The first electric machine 7 (ROV or drive) can be decoupled by the separating clutch 41, ie in the event of a fault, the first electric machine 7 (ROV or drive) is switched off. Between the separating clutch 41 and the first hydraulic motor 44, a hydraulic circuit of the second hydraulic machine 45 and the second hydraulic motor 51 is present. The separating clutch 41 is connected via a line 54 to the second channel 27. At 55, a flow control valve is designated. The second biasing spring 16.2 acts on the first pressure cylinder 17.1.

LIST OF REFERENCE NUMBERS

1 adjustment device

2 valve

3 drive device

4 adjusting device

5 pretensioner

6 volume flow

7 first electric machine

8 threaded spindle

8.1 drive end

8.2 Output end

9 spindle nut

9 'first position

9 "second position

10 longitudinal axis

11 ball element

12 hole

13 valve housing

14 valve channel

15 pipe

16.1 first preload spring

16.2 second preload spring

16.3 third preload spring

16.4 fourth preload spring

17.1 first pressure piston

17.2 second pressure piston

18.1 first pressure room

18.2 second pressure chamber

19 hydraulic cylinders

20 first channel

21 first switching valve

22 second switching valve

23 first spring 24 second spring

25 first solenoid

26 second solenoid

27 second channel

28 first check valve

29 housing

30 cylinder housing

31 pressure compensation

32 first spindle bearing

33 second spindle bearing

34 first lid

35 second lid

36 first hydraulic machine

37 electric motor

38 pressure fluid flow

39.1 first pressure gap

39.2 second pressure gap

40 entrainment element

41 separating clutch

42 drive shaft

43 second electric machine

44 first hydraulic motor

45 second hydraulic machine

46 third switching valve

47 fourth switching valve

48 second check valve

49 third check valve

50 hydraulic freewheel

51 second hydraulic motor

52 fifth switching valve

53 sixth switching valve

54 line

55 flow valve

56 drive axle

Claims

claims

1. Electrohydraulic system with an adjusting device (1) for a valve (2), with a drive device (3), with an adjusting device (4) and with a biasing means (5), wherein the in the biasing means (5) stored energy in case of failure on the adjusting device (4) is transferable, so that a rotational movement of the adjusting device (4) begins, which leads to the adjustment of the valve (2).

2. Electrohydraulic system according to claim 1, wherein the adjusting axis of the adjusting device (4) and the adjusting axis of the valve (2) are arranged coaxially with each other.

3. Electro-hydraulic system according to claim 1 or 2, wherein the adjusting device (4) comprises at least one mechanical threaded spindle (8) and at least one spindle nut (9).

4. Electrohydraulic system according to claim 1 or 2, wherein the adjusting device (4) comprises at least one rotatable hydraulic motor (44).

5. Electrohydraulic system according to one of the preceding claims, wherein the biasing means (5) comprises at least one spring system with at least one biasing spring (16.1, 16.2) by at least one hydraulic cylinder (19) with at least one pressure piston (17.1, 17.2) with at least one Pressure chamber (18.1, 18.2) is biased.

6. Electrohydraulic system according to claim 5, wherein the pressure chamber (18.1, 18.2) to at least one channel (20, 27) with at least one switching valve (21, 22) is connected, at the opening of the pressure piston (17.1, 17.2) of the hydraulic cylinder ( 19) is displaceable by the spring system.

7. Electrohydraulic system according to one of the preceding claims, wherein the drive means (3) for the adjusting device (4) comprises an electric machine (7) for a rotary drive of an external actuator or robot or a remote-controlled underwater vehicle.

8. Electrohydraulic system according to one of the preceding claims, wherein between the drive means (3) for the adjusting device (4) and the adjusting device (4) is provided a separating clutch (41).

9. Electrohydraulic system according to one of the preceding claims, wherein the drive means (3) for the adjusting device (4) with a hydraulic machine (45) is connected, which is connected to a hydraulic cylinder (19).

10. Electrohydraulic system according to one of the preceding claims, wherein between the drive means (3) for the adjusting device (4) and the adjusting device (4) a freewheel (50) is provided.