Electrohydraulic systems for valves

Abstract

The present invention relates to an electro-hydraulic system (100) for a valve, the electro-hydraulic system being configured to drive the valve in rotation, wherein the system (100) comprises the following components: an output shaft (10) which can be directly connected to the valve so as to drive the valve in rotation, and the output shaft extends along a first axis (Ax1); a hydraulic piston (20) which is configured to be operated by a pressure medium and is arranged to rotate the output shaft (10), wherein the hydraulic piston (20) extends along a second axis (Ax2) perpendicular to the first axis; a pre-tensioning device (30) which is configured to store energy by pre-tensioning an elastic element (31) and to transfer the energy to the output shaft in the event of a fault, thereby A predetermined position of an output shaft (10) can be ensured, wherein a preload device (30) is preloaded by at least one hydraulic cylinder (37), and wherein an elastic element (31) extends along a third axis (Ax3), wherein a hydraulic piston (20) is guided into a first cylinder housing (22) and a second cylinder housing (23), wherein at least one of the cylinder housings (22, 23) is connected to the hydraulic cylinder (37); and wherein a shut-off valve (53, 54) is arranged between one of the cylinder housings (22, 23) and the hydraulic cylinder (37), the shut-off valve being configured to decouple the preload device (30) from the hydraulic piston, and wherein a shut-off direction extends from the hydraulic cylinder (37) toward the one cylinder housing (22, 23).

Description

Technical Field

[0001] The present invention relates to the technical field of an electrohydraulic system for a valve, the electrohydraulic system being configured to drive the valve in rotation and being configured to rotate the valve into a predetermined rotational position and to secure this position in the event of a fault. The present invention relates in particular to an electrohydraulic device comprising the electrohydraulic system and a housing, the electrohydraulic system being accommodated in the housing. Background Art

[0002] Various variants are currently known which make it possible to rotate the rotary valve into a predetermined rotational position and to secure this position in the event of a fault. Such variants make it possible, in particular, to control the valve in the event of a fault in order to set a position in which the valve is closed and at the same time secure this position in order to ensure that the valve remains closed.

[0003] In such systems, the adjusting drive is usually coupled in such a way that the reset device is also moved simultaneously when the valve is adjusted. This has the consequence that a force for the reset must always be applied in order to adjust the valve, which means a significantly higher energy expenditure than simply actuating the valve. In addition, in conventional systems, it is not possible to operate the valve movement independently of the reset mechanism, so that the actuation power can be applied separately in time and the preload device does not have to be actuated every time the valve is actuated, since it is already preloaded.

[0004] It is therefore an object of the present invention to provide an electrohydraulic system for a valve which is compact, energy-efficient and enables valve actuation and pretensioning of a safety device in separate steps.

[0005] For this reason, the present invention provides a system and a method for realizing a compact rotary drive which is capable of providing a fail-safe emergency shutdown in the event of a failure of the electrical energy supply. Summary of the invention

[0006] The invention is based on the idea of ​​creating a hydraulic system in which the preload device can be decoupled from the hydraulic piston responsible for the rotation of the output shaft so that the piston can rotate the shaft independently of the preload force and can independently preload the spring, regardless of whether the valve is open or closed.

[0007] According to one embodiment of the present invention, there is provided an electro-hydraulic system for a valve, the electro-hydraulic system being configured to rotationally drive the valve; wherein the system comprises an output shaft which can be directly connected to the valve so as to rotationally drive the valve, and wherein the output shaft extends along a first axis; wherein the system comprises a hydraulic piston which is configured to be manipulated by a pressure medium and which is arranged to rotate the output shaft, wherein the hydraulic piston extends along a second axis which is perpendicular to the first axis; wherein the system comprises a pre-tensioning device which is configured to store energy by pre-tensioning an elastic element and In the event of a fault, the energy is transmitted to the output shaft so that the output shaft can be rotated into a predetermined position and this position can be ensured, wherein the preload device is preloaded by at least one hydraulic cylinder, and wherein the elastic element extends along a third axis; wherein the hydraulic piston is guided in a first cylinder housing and a second cylinder housing, wherein at least one of the cylinder housings is connected to the hydraulic cylinder; and wherein a shut-off valve is arranged between one of the cylinder housings and the hydraulic cylinder, the shut-off valve being configured to decouple the preload device from the hydraulic piston, and wherein a shut-off direction extends from the hydraulic cylinder toward the one cylinder housing. This solution is particularly advantageous because it is practically possible to provide an electrohydraulic system for a valve in which the preload device can be decoupled from the hydraulic piston so that the piston can rotate the shaft independently of the preload device and the spring can be preloaded independently, regardless of whether the valve is open or closed. This form of the two cylinder housings is particularly advantageous because it allows the use of a compact cylinder that is engaged with the drive shaft.

[0008] According to another embodiment of the invention, a system is provided, in which the predetermined position of the output shaft is a position in which the hydraulic piston is at a stop of one of the cylinder housings. This solution is particularly advantageous because it allows for a more stable positioning of the output shaft. As an alternative or in addition, the predetermined position can also be a position in which the piston of the hydraulic cylinder of the preload device is at a stop. As an alternative or in addition, the stop can be predetermined by a valve connected externally to the output shaft.

[0009] According to another embodiment of the present invention, a system is provided, in which both the first cylinder housing and the second cylinder housing are connected to the hydraulic cylinder via a shut-off valve, wherein the shut-off direction extends from the hydraulic cylinder to the first or second cylinder housing. This solution enables a hydraulic connection between the first cylinder housing and the hydraulic cylinder as well as a hydraulic connection between the second cylinder housing and the hydraulic cylinder. With this solution, the pretensioning device can be pretensioned both when the pressure medium is supplied to the first cylinder housing and when the pressure medium is supplied to the second cylinder housing. Therefore, the pretensioning can be carried out via different operating modes and the pretensioning process of the pretensioning device is effectively simplified.

[0010] According to another embodiment of the invention, a system is provided, wherein the shut-off valve is a non-return valve and wherein the system further comprises a pump which is connected to the valve seat side of the non-return valve. This solution enables the preload device to be decoupled from the cylinder housing using simple elements.

[0011] According to another embodiment of the invention, a system is provided, wherein the preload device comprises a connection device coupled to the output shaft, and wherein the connection device comprises the following elements: a first connection element, which is preferably in engagement with the toothing of the output shaft and moves along a fourth axis parallel to the third axis when the output shaft is rotated, wherein the end of the first connection element distal to the output shaft has a stop, and a second connection element, which is fixedly connected to the elastic element, wherein the second connection element is slidingly coupled to the first connection element and is arranged to drive the first connection element at the stop when the elastic element is relaxed. This solution is particularly advantageous because it makes it possible to rotate the output shaft into a predetermined position and to secure this position in the event of a fault using a very simple, reliable and compact system.

[0012] According to another embodiment of the invention, a system is provided, wherein the two cylinder housings are arranged above and below the output shaft, respectively, and the hydraulic piston comprises a rod section between the two cylinder housings, wherein the rod section has a toothing which engages with a toothing of the output shaft, wherein the piston is actuated by a pressure medium supplied to at least one of the cylinder housings. This form of the two cylinder housings is particularly advantageous, since it enables the use of a compact cylinder which engages with the drive shaft. In particular, the piston comprises both the connection function between the two cylinder housings and also the connection function to the output shaft.

[0013] According to another embodiment of the invention, a system is provided, wherein the elastic element comprises at least one spring system with at least one spring, in particular an arrangement of a plurality of springs arranged in parallel, wherein the spring or springs are arranged parallel to the third axis. This solution is particularly advantageous because it allows the use of known and permitted elements, such as a spring or an arrangement of a plurality of springs arranged in parallel, in a novel and compact system.

[0014] According to another embodiment of the invention, a system is provided, in which the second and third axes are parallel to each other and the first axis is perpendicular to the second and third axes. This solution is particularly advantageous because it is practically possible to provide an electrohydraulic system for valves that is compact and can therefore be applied to any rotary-actuated valve. The reason for this is that the axes arranged side by side allow the operating positions of the output shaft and the operating positions of the preload device to be decoupled along the output shaft. In addition, since the axes are parallel, a simple system can be achieved in which the main actuators are arranged side by side and parallel to each other.

[0015] According to another embodiment of the invention, a system is provided in which the second axis is offset relative to the third axis along the output shaft. This solution is particularly advantageous because it allows the length of the output shaft to be used advantageously in practice.

[0016] According to another embodiment of the present invention, an electro-hydraulic device is provided, which includes an electro-hydraulic system according to any one of the above-described embodiments and a housing, wherein the system is placed in the housing, wherein the housing has an elongated shape extending along the output shaft, wherein a cross section of the housing perpendicular to the output shaft and at the proximal end relative to an end section of the housing (arranged relative to the preload device) has two pairs of edges, wherein each pair of edges has two edges parallel to each other. With such an arrangement, a hydraulic system can be effectively provided, which can also be used underwater and can be easily coupled to an existing valve.

[0017] According to another embodiment of the invention, an electrohydraulic device is provided, wherein the cross section is polygonal, preferably square. With such a shape of the cross section, the device is particularly compact and can have standard dimensions.

[0018] According to another embodiment of the invention, an electrohydraulic device is provided, wherein an end section of the output shaft, which is arranged opposite the preload device, protrudes from the housing, and wherein the section can be reversibly connected to and disconnected from the valve. This solution allows a simple connection to an external valve.

[0019] According to another embodiment of the present invention, a method is provided to ensure a predetermined rotational position of a valve in the event of a fault, wherein the valve is configured to rotate about a first rotational axis by movement of an element along a second axis, wherein an elastic element is used to reach and ensure the predetermined position of the valve in the event of a fault, and the elastic element extends along a third axis in order to ensure the position of the valve, and wherein the second and third axes are parallel to each other and the first axis is perpendicular to the second and third axes. Such a method is completely consistent with one of the systems described in other embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention is described below with reference to the accompanying drawings, wherein the same reference numerals refer to the same components and / or similar components and / or corresponding components of the system.

[0021] Figure 1 A view schematically shows an electrohydraulic system according to one embodiment of the present invention;

[0022] Figure 2 Schematically shows a 3D view of an electrohydraulic device according to one embodiment of the present invention;

[0023] Figure 3 Schematically shows the elastic element under the condition of pre-tensioning Figure 1 A view of the electro-hydraulic system;

[0024] Figure 4 Schematic diagram showing the output shaft adjustment function from Figure 1 A view of the electro-hydraulic system;

[0025] Figure 5 Schematic diagram showing the Figure 1 View of the electro-hydraulic system. DETAILED DESCRIPTION

[0026] The invention will be described below with reference to specific embodiments as shown in the accompanying drawings. However, the invention is not limited to the specific embodiments described in the following detailed description and shown in the accompanying drawings, but the described embodiments only illustrate some aspects of the invention, the scope of which is defined by the preferred embodiments.

[0027] Other changes and variations of the present invention are clear to those skilled in the art. Thus, this description includes all changes and / or variations of the present invention, and their protection scope is defined by preferred embodiments.

[0028] In the following paragraphs, reference is made to Figure 1 The main components of the electro-hydraulic system are explained. First, the mechanical components are described in detail and then the hydraulic components are described in detail.

[0029] The electro-hydraulic system 100 includes an output shaft 10, wherein the output shaft 10 Figure 1 The end section shown on the right side of is configured for connection to a valve in order to be able to transmit a rotation of the output shaft 10 to the valve.

[0030] A toothing 12 is provided along the axis Ax1 (from now on simply referred to as the "first axis") of the output shaft 10, by which the output shaft can be rotated. That is, the hydraulic piston 20 moving along the second axis Ax2 transmits its axial movement to the drive shaft via the toothing arranged along the rod section of the hydraulic piston.

[0031] The hydraulic piston is guided in two cylinder housings 22 , 23 , wherein the first cylinder housing 22 is arranged below the output shaft 10 and the second cylinder housing 23 is arranged above the output shaft 10 .

[0032] As will be explained in greater detail during the course of the description, pressure medium is fed into one of the cylinder housings 22 , 23 in order to be able to control the axial position of the piston.

[0033] A preload device 30 is arranged along the first axis, which preload device is designed to achieve a rotational position of the output shaft 10 and to secure this rotational position in the event of a fault.

[0034] The pre-tightening device 30 includes an elastic element 31 , a first connecting element 32 and a second connecting element 35 .

[0035] The elastic element 31 is configured to store energy by its preload and transfer the energy to the output shaft 10 in the event of a fault, thereby ensuring a predetermined position of the output shaft 10. The elastic element 31 extends along a third axis Ax3 parallel to the second axis Ax2. The distance between a plane extending perpendicular to the first axis Ax1 and passing through the second axis Ax2 and a plane extending perpendicular to the first axis Ax1 and passing through the third axis Ax3, measured along a line parallel to the output shaft, is greater than zero, preferably in a range between 15 and 80 mm.

[0036] The elastic element 31 can preferably be as Figure 1 As shown in FIG. 1 , a spring is configured to store and transfer energy along a third axis Ax3.

[0037] The first connecting element 32 has a toothing 33 which engages with the toothing 11 of the output shaft 10 .

[0038] In particular, when the output shaft 10 rotates, the first connecting element 32 moves along a fourth axis Ax4 parallel to the third axis Ax3 .

[0039] In view of the foregoing description, it is clear that the second axis Ax2 and the third axis Ax3 are parallel to each other and the first axis Ax1 is perpendicular to the second axis Ax2 and the third axis Ax3.

[0040] The end of the first connecting element 32 which is arranged opposite the drive shaft and is the upper end section of the first connecting element 32 has a stop 34. As will become clearer from the further progress of the description, the stop is important for determining the final positioning of the output shaft.

[0041] In addition, the preload device 30 comprises a second connection element 35, which is fixedly connected to the elastic element 31. The second connection element 35 is slidably coupled to the first connection element 32 and is arranged to drive the first connection element 32 at the stop 34 when the elastic element 31 is relaxed.

[0042] As in Figure 1 As can be seen in the figure, the second connecting element 35 is directly connected to the hydraulic cylinder 37 so as to be able to transmit the movement of the piston of the hydraulic cylinder 37 to the elastic element 31. Therefore, the hydraulic cylinder can achieve the tensioning and relaxation of the elastic element by means of a hydraulic control mechanism, which controls the supply of pressure medium into the hydraulic cylinder and the output from the hydraulic cylinder.

[0043] Figure 2 Schematically shows a 3D view of an electro-hydraulic device 1000. The device comprises the electro-hydraulic system 100 described above and a housing 200 in which the system 100 is housed. Figure 2 As can be seen in FIG. 2 , the housing 200 has an elongated shape that extends along the output shaft 10 .

[0044] The depicted housing 200 is rectangular, and the axis of the cuboid is arranged parallel to the first axis of the output shaft 10. The shape of the housing 200 is not limited to a cuboid. In other words, the housing can preferably have any shape, wherein a cross section of the housing 200 perpendicular to the output shaft 10 and at the proximal end relative to the end section of the housing 200 has two pairs of edges, wherein each pair of edges has two edges parallel to each other.

[0045] The output shaft 10 is located Figure 2 An end section on the right side of the valve protrudes from the housing 200 and can be reversibly connected to and disconnected from the valve.

[0046] Now refer to Figure 3-5 The method is described, which is used to control the electro-hydraulic system 100 .

[0047] Figure 3 The steps for prestressing the elastic element 31 are shown. In the starting state, the hydraulic piston 20 is located at the stop in the second cylinder housing 23 in the upper end position. In this state, the two valves 55a and 55b are closed. In addition, in this starting position, the stop 34 of the first connecting element 32 is in engagement with the second connecting element 35.

[0048] The prestressing is carried out by pumping a pressure medium, such as oil, by means of a pump 50 which is preferably driven by an electric motor.

[0049] The pressure medium flows through a non-return valve 57 connected to the outside (eg, a tank) and reaches the inlet of the pump 50. The pressure medium is then pumped and flows from the outlet of the pump 50 in the direction indicated by D1 as far as the first shut-off valve 51.

[0050] In particular, because the hydraulic piston 20 is in the impact position, the pressure medium flows through the nonreturn valve 53 as far as the hydraulic cylinder 37 and does not flow into the first cylinder housing 22 .

[0051] As the pressure medium flows into the hydraulic cylinder 37 , the piston 38 is displaced downwardly along the third axis Ax3 by the hydraulic cylinder 37 in order to tension the elastic element 31 downwardly.

[0052] Since the piston 38 of the hydraulic cylinder 37 is fixedly connected to the second connecting element 35, the second connecting element is simultaneously pushed downward. Figure 3 As can be seen in FIG. 3 , the end section of the second connecting element 35 slides on the outer surface of the first connecting element 32. As a result, the first connecting element 32 remains fixedly at the same position.

[0053] After the elastic element 31 has been preloaded, the valves 53 and 54 decouple the piston 38 from the first and second cylinder housings 22 , 23 . The blocking directions 53 and 54 of the valves extend from the hydraulic cylinder 37 to the first and second cylinder housings 22 , 23 .

[0054] Due to this arrangement, the output shaft 10 can be rotated in two directions via the valves 51 and 52 without affecting the preload device 30 .

[0055] exist Figure 4 In the next step shown in , the rotational position of the output shaft 10 is adjusted by the pump 50. The positioning is adjusted by pumping a pressure medium which is fed into one of the two cylinder housings (see the direction D2 of the drawn arrow).

[0056] exist Figure 4 In the example shown in FIG. 2 , the pressure medium is delivered to the second cylinder housing 23. The piston 20 is thereby pushed downward, and thereby the output shaft 10 is rotated clockwise (in Figure 4 from right to left view).

[0057] The above-described rotation of the output shaft 10 causes a downward displacement of the first connecting element 32 due to the rotation of the toothing 11 of the output shaft 10 .

[0058] As in Figure 4 As can be seen in the drawing, the output shaft 10 can be rotated both clockwise and counterclockwise by means of a pump 50 that can rotate in both directions, so that a valve (not shown in the drawing) located at an end section of the output shaft 10 can be rotated in both directions.

[0059] If a pressure drop occurs at the preload cylinder 37 due to a leak in the system, the preload device 37 can be supplied with pressure medium via the drive motor 50 as a function of the instantaneous output shaft position without leaving the current position of the output shaft.

[0060] As an alternative to the method just described, the pretensioning device 30 can be pretensioned simultaneously with the rotation of the output shaft 10 .

[0061] In this case, the hydraulic piston 20 is also located at the stop in the second cylinder housing 23 in the upper end position in the starting state. In this state, the two valves 55a and 55b are closed. In addition, the stop 34 of the first connecting element 32 is in engagement with the second connecting element 35 in this starting position.

[0062] The prestressing is carried out by pumping a pressure medium by means of a pump 50. The pressure medium flows out of the first cylinder housing 23 and reaches the inlet of the pump 50. The pressure medium is then pumped and flows from the outlet of the pump 50 as far as the shut-off valve 52. The pressure medium flows via the non-return valve 54 as far as the hydraulic cylinder 37 and at the same time into the second cylinder housing 22.

[0063] As the pressure medium flows into the hydraulic cylinder 37, the piston 20 is displaced downward from the hydraulic cylinder 37 along the third axis Ax3 to tension the elastic element 31 downward. As the pressure medium flows into the second cylinder housing 22, the output shaft 10 is rotated by the piston 20 at the same time.

[0064] Therefore, in this case, the pretensioning of the pretensioning device 30 is performed simultaneously with the rotation of the output shaft 10 .

[0065] As in Figure 5 As can be seen in FIG. 1 , in the event of a fault, the energy stored in the elastic element is triggered by the relaxation of the elastic element and is transferred to the first and second connecting elements.

[0066] The second connecting element 35 is displaced upwards, in particular, by the force of the elastic element 31. Due to the interaction between the stop 34 and the second connecting element 35, the output shaft 10 is rotated to a predetermined position by means of the toothing 11, 33 of the output shaft 10 and the first connecting element.

[0067] The predetermined position can be the position of the piston 20 at the stop in the second cylinder housing 23 and / or the position of the piston 38 at the stop. As an alternative or in addition, the stop can be predetermined by a valve connected externally to the output shaft 10 .

[0068] Therefore, the piston is rotated by means of the toothing 11, 21 of the output shaft 10 and the piston 20 to a predetermined position, which corresponds to the position at Figure 1 and 3 The position shown in the figure is consistent with that in the figure.

[0069] The following paragraphs describe in detail how the electrohydraulic system can be actuated in the event of a fault.

[0070] First, the outlet valves 55 a and 55 b are adjusted into the open position in order to be able to carry the pressure medium flowing from the hydraulic cylinder 37 in the direction D3 outward (for example to a tank).

[0071] At the same time, because the output shaft 10 is rotated and the piston 20 is pushed upward, the pressure medium in the second cylinder housing 23 is entrained outward in the direction D4 through the check valve 54 and the outlet valves 55 a and 55 b .

[0072] The pressure in the first cylinder housing 22 therefore drops and the inlet valve 56 opens, so that pressure medium can reach the first cylinder housing 22 from the outside (for example from a tank) in the direction indicated by D5 .

[0073] In this state, the rotational position of output shaft 10 is thus ensured.

[0074] The present invention has been described with reference to the embodiments described above, and it is clear to those skilled in the art that different modifications, changes and improvements to the present invention can be implemented according to the teachings described above and within the scope of the accompanying preferred embodiments without departing from the scope of protection of the present invention.

[0075] For example, even if the elastic element in the figures only comprises one elastic spring, the elastic element can also comprise an arrangement of multiple springs arranged in parallel. However, it is important that the springs are arranged parallel to the third axis. It goes without saying that the elastic element can be a hydraulic accumulator configured to store and transfer energy along the third axis Ax3.

[0076] In addition, the starting state of the piston 20 can be Figure 1 and 3 The positions indicated are opposite.

[0077] Additionally, in order to unnecessarily obscure the described invention, the following areas are not described herein, in which those skilled in the art would be proficient.

[0078] Accordingly, the present invention should not be limited to the specific illustrative embodiments, but only within the scope of the accompanying preferred embodiments.

[0079] List of reference numerals:

[0080] 10 Output shaft

[0081] 11 Output shaft teeth

[0082] 12 Output shaft teeth

[0083] 20 Hydraulic piston

[0084] 21 Rod Section

[0085] 22 First cylinder housing

[0086] 23 Second cylinder housing

[0087] 30 Preload device

[0088] 31 Elastic element

[0089] 32 First connecting element

[0090] 33 toothed portion of the first connecting element

[0091] 34 Stop

[0092] 35 Second connecting element

[0093] 37 Hydraulic Cylinder

[0094] 38 Piston of hydraulic cylinder

[0095] 50 Pumps

[0096] 51, 52, 43, 54, 55a, 55b, 56, 57 valves

[0097] Ax1 First axis

[0098] Ax2 Second axis

[0099] Ax3 The third axis

[0100] Ax4 Fourth axis

[0101] 100 Electro-hydraulic system

[0102] 200 Shell

[0103] 1000 Electro-hydraulic unit.

Claims

1. An electrohydraulic system (100) for a valve, the electrohydraulic system being configured for rotationally actuating the valve, wherein: The system (100) comprises the following components: an output shaft (10) which is directly connectable to the valve so as to rotatably drive the valve, and which extends along a first axis (Ax1); a hydraulic piston (20) configured to be actuated by a pressure medium and arranged to rotate the output shaft (10), wherein the hydraulic piston (20) extends along a second axis (Ax2) perpendicular to the first axis; A pretensioning device (30) is configured to store energy by pretensioning an elastic element (31) and to transfer the energy to the output shaft in the event of a fault, thereby ensuring a predetermined position of the output shaft (10), wherein the pretensioning device (30) is pretensioned by at least one hydraulic cylinder (37), and wherein the elastic element (31) extends along a third axis (Ax3), It is characterized in that The hydraulic piston (20) is guided into a first cylinder housing (22) and a second cylinder housing (23), wherein at least one of the cylinder housings (22, 23) is connected to the hydraulic cylinder (37); and A shut-off valve (53, 54) is arranged between one of the cylinder housings (22, 23) and the hydraulic cylinder (37), the shut-off valve being configured to decouple the preload device (30) from the hydraulic piston, wherein a shut-off direction extends from the hydraulic cylinder (37) toward the one cylinder housing (22, 23), Wherein, the second axis is offset relative to the third axis along the output shaft.

2. The system (100) according to claim 1, wherein: The predetermined position of the output shaft (10) is a position in which the hydraulic piston (20) is located at a stop of one of the cylinder housings (22, 23).

3. The system (100) according to claim 1 or 2, wherein: Both the first cylinder housing (22) and the second cylinder housing (23) are connected to the hydraulic cylinder (37) via shut-off valves (53, 54), wherein the shut-off direction extends from the hydraulic cylinder (37) toward the first or second cylinder housing (22, 23).

4. The system according to claim 1 or 2, wherein: The shutoff valves (53, 54) mentioned are non-return valves, and the system further comprises a pump (50) which is connected to the valve seat side of the non-return valves.

5. The system according to claim 1 or 2, wherein: The preload device (30) comprises a connection device coupled to the output shaft (10), wherein the connection device comprises the following elements: a first connecting element (32) which is engaged with the toothed portion (11) of the output shaft (10) and moves along a fourth axis (Ax4) parallel to the third axis (Ax3) when the output shaft (10) rotates, wherein the first connecting element (32) has a stopper (34) at its distal end relative to the output shaft (10); A second connecting element (35), the second connecting element is fixedly connected to the elastic element (31), wherein the second connecting element (35) is slidably coupled to the first connecting element (32), and the second connecting element is arranged to drive the first connecting element (32) at the stop (34) when the elastic element (31) is relaxed.

6. The system (100) according to claim 1 or 2, wherein: The two cylinder housings (22, 23) are arranged above and below the output shaft (10), respectively, and the hydraulic piston (20) comprises a rod section (21) located between the two cylinder housings (22, 23), wherein the rod section (21) has a toothing which is in engagement with a toothing (12) of the output shaft (10), wherein the piston (20) is actuated by a pressure medium supplied to at least one of the cylinder housings (22, 23).

7. The system (100) according to claim 1 or 2, wherein: The elastic element (31) comprises at least one spring system with at least one spring, wherein the spring or the springs are arranged parallel to the third axis (Ax3).

8. The system (100) according to claim 1 or 2, wherein: The third axis (Ax3) is arranged perpendicular to the first axis (Ax1).

9. The system (100) according to claim 1 or 2, wherein: The second axis (Ax2) and the third axis (Ax3) are parallel to each other, and the first axis (Ax1) is perpendicular to the second axis (Ax2) and the third axis (Ax3).

10. An electro-hydraulic device (1000), comprising an electro-hydraulic system (100) according to any one of claims 1 to 9 and a housing (200), wherein the system (100) is housed in the housing, wherein: The housing (200) has an elongated shape extending along the output shaft (10), wherein a cross section of the housing (200) perpendicular to the output shaft (10) and at a proximal end relative to an end section of the housing (200) has two pairs of edges, wherein each pair of edges has two edges parallel to each other.

11. The device (1000) according to claim 10, wherein: The cross section is polygonal.

12. The device (1000) according to any one of claims 10 or 11, wherein: An end section of the output shaft (10) arranged opposite the preload device protrudes from the housing (200), wherein the end section can be reversibly connected to and disconnected from the valve.

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