Switching device for switching rolls, rotary tilt comprising a switching device, and system comprising a rotary tilt and a roll stand

Abstract

The invention relates to a switching device (10) for switching rollers (12) for rolling rod-shaped or wire-shaped rolling stock, which rollers are fixed to a roller shaft body (14) in a rotationally fixed manner by means of dynamic coupling in order to be able to transmit a rolling torque from the roller shaft body (14) to the rollers (12). The switching device (10) has a fluid connection (16) for connecting a fluid line (18) to a bore (15) of the roll shaft body (14) and a hydraulic unit (20) for applying a high pressure to a fluid in the fluid line (18). The hydraulic unit (20) is designed as a hydraulic supercharger, which has a low-pressure cylinder (22), a low-pressure piston (24) and a low-pressure fluid on the low-pressure side and a high-pressure cylinder (26), a high-pressure piston (28) and a high-pressure fluid on the high-pressure side. Wherein the low-pressure side is fluidly separated from the high-pressure side, such that the low-pressure fluid is substance-separated from the high-pressure fluid.

Description

Technical Field

[0001] The present invention relates to a switching device for switching rollers used for rolling rod-shaped or linear rolled products. The rollers are torsionally fixed to the roller shaft by a dynamic coupling so that the rolling torque can be transmitted from the roller shaft to the rollers. The switching device includes a fluid interface for connecting a fluid pipeline to a hole in the roller shaft, and a hydraulic unit for applying high pressure to the fluid in the fluid pipeline. The hydraulic unit is designed as a hydraulic booster, which has a low-pressure cylinder, a low-pressure piston, and a low-pressure fluid on the low-pressure side, and a high-pressure cylinder, a high-pressure piston, and a high-pressure fluid on the high-pressure side.

[0002] Furthermore, the invention relates to a rotary and tilting table for moving the rolling stands of a rolling mill from an upright working orientation into an inclined switching orientation and for rotating the rolling stands in the switching orientation into a switching position by means of such a switching device.

[0003] Finally, the present invention relates to a system consisting of such a rotary and tilting table and a rolling mill stand. Background Art

[0004] DE 103 05 039 A1 describes a rolling mill stand for rolling rods or tubes. In the stand housing, three rolls are each fixed in a rotationally fixed manner via a dynamic coupling to a roll shaft rotatably mounted in the stand housing, so that the rolling torque can be transmitted from the roll shaft to the respective roll.

[0005] In order to obtain high-quality rolled products, these rolls need to be regularly replaced with new or modified rolls, since the rolls wear out during use. As is known, the dynamic coupling between the rolls and the roll shaft is released by applying hydraulic oil to the rolls at a very high pressure of 4000-6000 bar, which is displaced radially outwards from the roll shaft. The rolls expand slightly due to the hydraulic oil, thereby releasing the dynamic coupling so that the rolls can be separated from the roll shaft. The above-described process is also used when joining the rolls to the roll shaft. This principle is generally accepted and is described, for example, in CN 217 859829U

[0006] To achieve extremely high hydraulic oil pressures, pressure intensifiers are used. These, in a known manner, multiply the pressure of the low-pressure hydraulic oil to generate high-pressure hydraulic oil. When the rolls expand during engagement or disengagement, this high-pressure hydraulic oil is forced out through the gap between the rolls and the roll shaft and is subsequently consumed, as its quality after leaving the hydraulic system is no longer sufficient for the sensitive hydraulic system.

[0007] Therefore, the problem in the prior art is that replacing the rollers requires consuming a relatively large amount of high-quality hydraulic oil, which is both costly and harmful to the environment. Summary of the Invention

[0008] In view of this, an object of the present invention is to provide a switching device in the above technical field, by means of which the consumption of hydraulic oil when switching rollers can be reduced.

[0009] The solution for achieving the above object of the present invention is provided by the switching device according to claim 1, the rotary and tilting table according to claim 14, and the system consisting of the rotary and tilting table and the rolling mill stand according to claim 16. Advantageous technical solutions of the present invention are described in the dependent claims.

[0010] A switching device for switching rollers for rolling rod-shaped or wire-shaped rolled materials, wherein the rollers are torsionally fixed to the roller shaft by power coupling so as to be able to transmit the rolling torque from the roller shaft to the rollers, wherein the switching device has a fluid interface for connecting the fluid pipeline to the hole on the roller shaft and a hydraulic unit for applying high pressure to the fluid in the fluid pipeline, wherein the hydraulic unit is designed as a hydraulic booster, and the booster has a low-pressure cylinder, a low-pressure piston and a low-pressure fluid on the low-pressure side, and a high-pressure cylinder, a high-pressure piston and a high-pressure fluid on the high-pressure side, and is characterized in that the low-pressure side is separated from the high-pressure side fluid, so that the low-pressure fluid is separated from the high-pressure fluid material.

[0011] This allows the high-pressure side to be operated using a different fluid than the low-pressure side. This, in turn, allows for the use of a less demanding fluid as the high-pressure fluid, since the complex hydraulic circuits required for the low-pressure side are not required to reliably and precisely operate the switching device, particularly to control or regulate the delivery of the high-pressure fluid to the fluid connections. The separation of the low-pressure and high-pressure fluids allows the use of high-quality hydraulic oil with a lower viscosity and extremely high purity on the low-pressure side, while a different fluid with greater environmental compatibility and lower purity can be used on the high-pressure side. This allows for reuse, as the high-pressure fluid does not need to be housed in the more demanding hydraulic circuits on the low-pressure side. In particular, the high-pressure fluid can be used directly only for the joining or separation process between the roll and the roll shaft, allowing the discharged high-pressure fluid to be collected and reused, as it does not need to meet the high demands placed on the hydraulic fluid in complex hydraulic circuits with sensitive valve technology. The low-pressure fluid can then remain in the circuit without significant losses.

[0012] For this purpose, preferably no highly sensitive standard hydraulic components are installed on the high-pressure side; the valve technology on the high-pressure side preferably only has dirt-sensitive non-return valves.

[0013] In a preferred embodiment, the low-pressure side includes a hydraulic circuit having a proportional valve acting on the low-pressure fluid. Alternatively, the low-pressure side preferably includes a hydraulic circuit having a regulating pump acting on the low-pressure fluid. Furthermore, as an alternative, the low-pressure side preferably includes a hydraulic circuit having a speed-regulating and metering pump acting on the low-pressure fluid.

[0014] These three alternatives of the preferred embodiment allow the high-pressure fluid flow to be controlled or regulated in a manner adapted to the respective application, in particular to be reduced to the amount required to engage or disengage the rolls on the roll shaft. This improves the process otherwise used, in which high-pressure fluid, in particular hydraulic oil, is pressed into the joint gap at a constant, unadjustable rate, thereby conveying more oil than absolutely necessary into the gap between the roll and the roll shaft.

[0015] Advantageously, the high-pressure side has an unpressurized fluid reservoir for accommodating high-pressure fluid, wherein the high-pressure side is adapted to accommodate high-pressure fluid from the fluid reservoir, apply high pressure to it via a high-pressure piston, and deliver it to the fluid interface via a fluid line.

[0016] This makes it possible to simply supply high-pressure fluid to the fluid connection. By directly receiving the high-pressure fluid from the fluid reservoir, pressurizing it, and conveying it to the fluid connection via the fluid line, the high-pressure side can be designed in a simple manner and is therefore very insensitive to contamination, the purity of the high-pressure fluid, and the viscosity requirements of the high-pressure fluid.

[0017] The hydraulic assembly is preferably at least partially arranged below the liquid level of the high-pressure fluid in the fluid storage tank. This allows for reliable containment of the high-pressure fluid, as gravity supports the high-pressure fluid when it is delivered to the high-pressure side of the hydraulic assembly.

[0018] The hydraulic unit is further preferably at least partially arranged in a fluid storage tank. Like this, high-pressure fluid can be reliably accommodated because the high-pressure fluid is directly located on the hydraulic unit and a fluid line from the fluid storage tank to the hydraulic unit can be omitted.

[0019] Advantageously, the switching device includes a feed pump that can draw high-pressure liquid from a fluid reservoir and support the filling of the high-pressure piston at a lower feed pressure (e.g., 5 to 10 bar). This ensures that the high-pressure fluid is safely and continuously applied to the high-pressure piston and ensures its operation.

[0020] The switching device preferably also includes a device for returning the high-pressure fluid to the fluid storage tank. High-pressure fluid consumption can be further reduced by collecting the high-pressure fluid that escapes from the gap and returning it to the fluid storage tank. This has been impossible to achieve until now, or only at great expense, because the quality requirements of the hydraulic oil (which, according to the switching device, no longer need to be met on the high-pressure side) and the purity requirements of the hydraulic oil would result in extremely high filtration and processing costs. By separating the less demanding high-pressure fluid from the low-pressure fluid, the return and reuse of the high-pressure fluid can be economical and significantly reduce high-pressure fluid consumption.

[0021] In a preferred embodiment, the device for returning the high-pressure fluid has a pump and a filter for filtering the high-pressure fluid. By these measures, it is particularly easy to collect the high-pressure fluid discharged from the gap, return it to the fluid storage tank and reuse it.

[0022] Advantageously, the switching device is designed so that the high-pressure fluid has a higher viscosity than the low-pressure fluid. The higher viscosity of the high-pressure fluid applied to the rollers and discharged through the gap between the rollers and the roller shaft results in less high-pressure fluid being able to escape through the gap, as high-viscosity fluids have more difficulty flowing through narrow gaps than low-viscosity fluids and flow in smaller quantities. Conventional switching devices require a compromise in viscosity between avoiding fluid loss through the gap and ensuring reliable operation of the hydraulic unit. Traditionally, hydraulic equipment uses oil with a viscosity of VG46. By separating the low-pressure and high-pressure fluids, a common viscosity is no longer necessary, allowing the high-pressure fluid to have a higher viscosity than the low-pressure fluid. Consequently, the high-pressure fluid can have a viscosity of VG400 or higher, independent of the low-pressure fluid, because it is separated from the demanding hydraulic circuits on the low-pressure side of the hydraulic unit. Consequently, the fluid required for separation and engagement can be significantly reduced compared to using lower-viscosity fluids.

[0023] The high-pressure side is preferably suitable for using alternative media such as ethylene glycol or glycerin as the high-pressure fluid. Ethylene glycol, glycerin, or similar media are sufficient as high-pressure fluids but are more environmentally friendly than mineral oil. Ethylene glycol or glycerin are unsuitable for use on the low-pressure side of the hydraulic unit because they do not meet the requirements of valve technology, particularly in standard hydraulic circuits. However, the switching device of the present invention, which separates the low-pressure fluid from the high-pressure fluid, allows the use of such media and further improves the environmental compatibility of the switching device.

[0024] In a preferred embodiment, the switching device further comprises a control device adapted to control or regulate the amount of low-pressure fluid supplied to the hydraulic unit, thereby controlling or regulating the amount of high-pressure fluid supplied to the fluid connection. The control device can be, in particular, a conventional, appropriately programmed electronic data processing device, but can also be a special control device designed for controlling or regulating the amount of low-pressure fluid supplied to the hydraulic unit. This allows for particularly precise and efficient operation of the switching device.

[0025] The high-pressure piston preferably includes a seal that activates when the high-pressure piston is retracted, allowing the high-pressure piston to draw high-pressure fluid from a reservoir. Because the high-pressure fluid is separated from the low-pressure fluid, the high-pressure piston can advantageously draw the high-pressure fluid independently, for example from a fluid reservoir or other source. Alternatively, the high-pressure fluid can be externally delivered to the high-pressure side of the hydraulic unit.

[0026] To draw in high-pressure fluid, the seal of the high-pressure piston must be designed in such a way that, when the high-pressure piston is advanced, the high pressure is not only applied to the medium in the high-pressure cylinder. The high-pressure seals commonly used in these high-pressure pistons currently only work in one direction: the advancement direction. However, if the high-pressure piston must also draw in fluid, a seal should also be provided in the retraction direction to generate the suction force that draws in the fluid in as tightly and loss-free a manner as possible. This can be achieved, for example, by means of an additional lip seal that is active when the high-pressure piston is retracted.

[0027] A preferred rotary and tilting table for moving a rolling mill stand from an upright working orientation into an inclined switching orientation and for rotating the rolling mill stand in the switching orientation into a switching position has a switching device as described above.

[0028] This type of rotary tilting table allows for particularly efficient use of the aforementioned switching device. It allows for particularly easy, rapid, and error-free installation of the rolls in the roll stand, even though a switching device is not required. For example, a crane or similar device can be used to suspend the roll stand on the rotary tilting table. In this case, in a first step, the rotary tilting table can tilt the roll stand with the rolls (e.g., three rolls) into an inclined switching orientation, which can be, for example, horizontal.

[0029] After one roll has been replaced, the rolling stand can be rotated in the changeover orientation by rotating the tilting table, for example by 120° in the case of a rolling stand with three rolls, so that the next roll can be moved to the position of the previously processed roll. This is particularly advantageous when the rolls are changed by a robot that is fixed in position or relatively difficult to move.

[0030] In a preferred embodiment, the rotary and tilting table has a first hydraulic cylinder for tilting the rolling mill stand between a working orientation and a switching orientation, a second hydraulic cylinder for rotating the rolling mill stand in the switching orientation, and a hydraulic unit for supplying the first and second hydraulic cylinders, wherein the hydraulic unit is adapted to supply the low-pressure side of the hydraulic unit of the switching device. Since the rolling mill stand of a rolling mill can easily have a mass of 4 to 8 tons, it is particularly advantageous to tilt, rotate, and position the rolling mill stand using hydraulic cylinders. It is further advantageous in this case if the rotary and tilting table has its own hydraulic unit, which is connected to the rotary and tilting table and can supply hydraulic fluid at the required pressure to its hydraulic cylinders. In this case, it is particularly preferred that the hydraulic unit also supplies low-pressure fluid to the hydraulic unit of the switching device.

[0031] Further advantages and improvements of the invention can be found in the following description of the figures and in the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the hydraulic concept of the preferred intensifier.

[0033] Figure 2 Detailed view of the high pressure side of a preferred supercharger.

[0034] Figure 3 for Figure 2 An enlarged view of the portion shown.

[0035] Figure 4 A rotating and tilting table is preferred. DETAILED DESCRIPTION

[0036] Figure 1 Schematic diagram of the hydraulic concept of a preferred switching device 10 for switching a roll 12 for rolling rod-shaped or wire-shaped rolling stock, which is fixed in a rotationally fixed manner on a roll shaft 14 via a dynamic coupling in order to be able to transmit the rolling torque from the roll shaft 14 to the roll 12 . Figure 1 The roll assembly is schematically shown, consisting of a roll 12 and a roll shaft 14. Inside the roll shaft 14, holes 15 are provided, which simultaneously serve as fluid lines in the roll shaft 14.

[0037] The fluid connected to the hole 15 from the outside via the fluid interface 16 is delivered through the hole 15 inside the roller shaft 14 to the position where the roller 12 rests on the roller shaft 14 in a dynamic coupling manner. By applying a particularly high pressure at this point, the roller 12 can be caused to slightly expand on the roller shaft 14, thereby releasing the dynamic coupling. In this case, the roller 12 can move on the roller shaft 14. Figure 1As shown, the roller shaft body 14 is at least partially tapered, so that the roller shaft body 14 has a thicker end and a thinner end at respective sides opposite to each other. In the preferred technical solution of the roller shaft body 14, the roller 12, which has been expanded due to the high pressure from the roller shaft body 14, can be relatively easily disassembled toward the thinner end of the roller shaft body 14.

[0038] The concept of expanding the roll body 12 (more precisely the hub of the roll body 12 ) by applying hydraulic oil at an ultrahigh pressure of several thousand bar to the roll body 14 is also known in principle to a person skilled in the art, for example from DE 103 05 039 A1, and is therefore only briefly explained here.

[0039] The fluid connection 16 of the switching device 10 is used to firmly connect the fluid line 18 of the switching device 10 to the hole 15 of the roller shaft 14. The fluid under extremely high pressure reaches the roller shaft 14 through the fluid line 18 and reaches the hub of the roller 12 through the hole 15.

[0040] The fluid guided in the fluid line 18 is pressurized by a hydraulic unit 20, which is designed as a hydraulic booster and has a low-pressure cylinder 22, a low-pressure piston 24, a high-pressure cylinder 26 and a high-pressure piston 28. Therefore, the hydraulic unit 20 has a low-pressure side and a high-pressure side, wherein the pressure at the low-pressure side is lower than the pressure at the high-pressure side. The effective surface area of the low-pressure piston 24 is significantly larger than that of the high-pressure piston 28, so that the pressure at the low-pressure side can be increased according to the area ratio between the active surface of the low-pressure piston 24 and the active surface of the high-pressure piston 28. This principle is already known in principle to those skilled in the art from the prior art. Low-pressure fluid is applied to the low-pressure side of the hydraulic unit 20 via the low-pressure inlet line 23 or the low-pressure outlet line 25. When the low-pressure fluid delivered via the low-pressure inlet line 23 applies a relatively low pressure to the low-pressure piston 24, Figure 1 The piston in is pressed to the left and simultaneously moves the high-pressure piston 28 which is integrally connected to the low-pressure piston 24 , so that every movement of the low-pressure piston 24 is also achieved by the high-pressure piston 28 in the same manner.

[0041] On the contrary, the low pressure fluid delivered through the low pressure outlet line 25 will cause the low pressure piston 24 and Figure 1 The high pressure piston 28 in the low pressure piston 24 moves to the right. In this case, it is important to have a pressure differential between the left and right sides of the low pressure piston 24, which can be regulated by the pressure of the low pressure fluid in the low pressure inlet 23 and the low pressure outlet 25.

[0042] By applying a relatively low pressure to the low-pressure piston 24 to move the high-pressure piston 28, a high pressure is generated in the high-pressure cylinder 26, corresponding to the area between the low-pressure piston 24 and the high-pressure piston 28. The high-pressure fluid in the high-pressure cylinder 26 is pressurized by the valve designed as a check valve 19 and then forced into the fluid line 18, exerting a correspondingly high pressure on the high-pressure fluid in the fluid line 18. The check valve 19 only allows the high-pressure fluid to flow from the high-pressure cylinder 26 toward the fluid line 18. Therefore, when the high-pressure piston 28 is retracted again and the pressure inside the high-pressure cylinder 26 drops, the high pressure inside the fluid line 18 still remains.

[0043] The high pressure fluid can be introduced into the high pressure cylinder 26 through another check valve 19. An input line 35 is installed on the second check valve 19, which delivers the unpressurized high pressure fluid to the high pressure cylinder 26. Figure 1 In the preferred embodiment shown, a feed pump 34 is also installed on the inlet line 35. This feed pump creates an overpressure in the high-pressure fluid in the inlet line 35 relative to the unpressurized high-pressure cylinder 26, thereby simplifying the delivery of the fluid. At the same time, the retraction of the high-pressure piston 28 creates a negative pressure inside the high-pressure cylinder 26. This negative pressure also helps to draw in fresh high-pressure fluid, which is largely unpressurized at this point in time, through the inlet line 35 by means of the feed pump 34.

[0044] The high-pressure fluid inside the high-pressure cylinder 26 is then pressurized by the corresponding movement of the high-pressure piston 28 and escapes from the high-pressure cylinder 26 into the fluid line 18 through the check valve 19 .

[0045] The input line 35 is fed by the high-pressure fluid collected in the fluid reservoir 30. In this case, the input line 35 is preferably always located below the liquid level 32 of the high-pressure fluid in the fluid reservoir 30. This ensures that there is always enough high-pressure fluid available to fill the high-pressure cylinder 26.

[0046] In particular, the high-pressure fluid in the fluid reservoir 30 is filled via a return line 37. The return line 37 is in turn fed by a collecting container 17, into which the high-pressure fluid that escapes from the bore 15 in the roll shaft 14 when the rolls 12 are switched is collected. The collected high-pressure fluid is collected in the collecting container 17 and directed to the fluid reservoir 30 via the return line 37. In this case, filtration via a filter 38 in the return line 37 and a return pump 36 further facilitate the directing of the high-pressure fluid collected in the collecting container 17 to the fluid reservoir 30.

[0047] Unlike conventional boosters, in the preferred embodiment of the hydraulic unit 20, the retraction of the high-pressure piston 28 is also used to generate negative pressure in the high-pressure cylinder 26. Therefore, in addition to the feed pump 34, it is also used to apply force to the fluid in the input pipeline 35 to make it flow into the high-pressure cylinder 36. To this end, the high-pressure piston 28 needs to be moved not only in the pressure direction (i.e., in the direction of the pressure) but also in the direction of the pressure. Figure 1 To seal in the direction of suction (ie in the Figure 1 to the right) to seal.

[0048] Figure 2 and Figure 3 This is a detailed view of the high-pressure side of the pressure intensifier of the hydraulic unit 20. It shows the high-pressure cylinder 26 and the high-pressure piston 28, along with their seals. In this figure, particular attention should be paid to the seal 40, which is designed as a lip seal and reliably generates negative pressure inside the high-pressure cylinder 26 because it prevents low-pressure fluid to the right of the high-pressure piston 28 from flowing back toward the high-pressure cylinder.

[0049] Figure 4 A preferred rotary and tilting table 42 is shown, which is used in conjunction with a preferred switching device. The rotary and tilting table 42 has the switching device 10 described above. The rotary and tilting table 42 is used to move the rolling mill stand of a rolling mill from an upright working orientation to an inclined switching orientation and, in this switching orientation, to rotate the rolling mill stand into a switching position, using hydraulic fluid for this purpose.

[0050] The fluid used for these movements of the rolling mill stand on the rotating and tilting table is at the same pressure as the low-pressure fluid from the above-mentioned switching device 10. Therefore, preferably, the low-pressure inlet line 23 and the low-pressure outlet line 25 belong to the same hydraulic circuit as the hydraulic cylinder in the rotating and tilting table 42. Figure 4 One of the hydraulic cylinders 44 is shown.

[0051] The present invention makes it possible to separate the hydraulic circuit of the rotary and tilting table, which has complex, particularly demanding, and contamination-prone valve technology, from the hydraulic oil used to release the dynamic coupling between the rolls 12 and the roll shaft 14. This allows the use of a high-quality, extremely clean fluid as the hydraulic fluid for the rotary and tilting table 42, particularly the low-pressure fluid in the switching device 10, while some contamination may be tolerated as the high-pressure fluid used to release the dynamic coupling, which would otherwise be unacceptable in the valve technology of the fluid circuit in the rotary and tilting table 42. Furthermore, the present invention makes it possible to use environmentally friendly, non-mineral oil-based fluids as the high-pressure fluid, which are unsuitable as low-pressure fluids, particularly due to the demanding valve technology.

[0052] Reference Signs

[0053] 10 Switching device

[0054] 12 rollers

[0055] 14 Roller shaft

[0056] 15 holes

[0057] 16 fluid interfaces

[0058] 17 Collection Container

[0059] 18 fluid lines

[0060] 19 Check valve

[0061] 20 hydraulic units

[0062] 22 Low-pressure cylinder

[0063] 23 Low voltage incoming line

[0064] 24 Low pressure piston

[0065] 25 low voltage outlet

[0066] 26 High-pressure cylinder

[0067] 28 High-pressure piston

[0068] 30 fluid storage tanks

[0069] 32 Liquid Level

[0070] 34 Feed Pump

[0071] 35 Input pipeline

[0072] 36 Return pump

[0073] 37 Return pipeline

[0074] 38 filters

[0075] 40 seals

[0076] 42 Rotating and tilting table

[0077] 44 First hydraulic cylinder.

Claims

1. A switching device (10) for switching rollers (12) for rolling rod-shaped or wire-shaped rolling products, wherein the rollers are fixed to the roller shaft (14) in a torsionally fixed manner by a dynamic coupling so that a rolling torque can be transmitted from the roller shaft (14) to the rollers (12). The switching device (10) has a fluid interface (16) for connecting a fluid pipeline (18) to a hole (15) on the roller shaft (14) and a hydraulic unit (20) for applying high pressure to the fluid in the fluid pipeline (18). The hydraulic unit (20) is designed as a hydraulic booster, which has a low-pressure cylinder (22), a low-pressure piston (24) and a low-pressure fluid on the low-pressure side, and a high-pressure cylinder (26), a high-pressure piston (28) and a high-pressure fluid on the high-pressure side. It is characterized by: The low pressure side is fluidly separated from the high pressure side, such that the low pressure fluid is separated from the high pressure fluid material.

2. The switching device (10) according to claim 1, wherein the low-pressure side comprises a hydraulic circuit having a proportional valve acting on the low-pressure fluid.

3. The switching device (10) according to claim 1, wherein the low-pressure side comprises a hydraulic circuit having a regulating pump acting on the low-pressure fluid.

4. The switching device (10) according to claim 1, wherein the low-pressure side comprises a hydraulic circuit having a speed-regulated quantitative pump acting on the low-pressure fluid.

5. A switching device (10) according to any one of claims 1 to 4, wherein the high-pressure side has an unpressurized fluid storage tank (30) for accommodating the high-pressure fluid, wherein the high-pressure side is suitable for accommodating the high-pressure fluid from the fluid storage tank (30), applying high pressure to the high-pressure fluid through the high-pressure piston (28), and transporting the high-pressure fluid to the fluid interface (16) through the fluid pipeline (18).

6. The switching device (10) according to claim 5, wherein the hydraulic unit (20) is at least partially arranged below the fluid level (32) of the high-pressure fluid in the fluid storage tank (30).

7. The switching device (10) according to claim 5 or 6, wherein the hydraulic unit (20) is at least partially arranged in the fluid storage tank (30).

8. The switching device (10) according to claim 7, wherein the switching device (10) comprises a feed pump (34), which is suitable for sucking high-pressure liquid from the fluid storage tank (30) and supporting the filling of the high-pressure piston (28).

9. The switching device (10) according to any one of claims 5 to 8, further comprising a device for returning the high-pressure fluid to the fluid storage tank (30).

10. The switching device (10) according to claim 9, wherein the device for returning the high-pressure fluid comprises a return pump (36) and a filter (38) for filtering the high-pressure fluid.

11. The switching device (10) according to any one of claims 1 to 10, wherein the switching device is designed such that the viscosity of the high-pressure fluid is higher than that of the low-pressure fluid.

12. The switching device (10) according to any one of claims 1 to 11, wherein the high-pressure side is suitable for using ethylene glycol or glycerol as high-pressure fluid.

13. The switching device (10) according to any one of claims 1 to 12 further comprises a control device, which is suitable for controlling or regulating the amount of low-pressure fluid delivered to the hydraulic unit (20) so as to thereby control or regulate the amount of high-pressure fluid delivered to the fluid interface (16).

14. A switching device (10) according to any one of claims 1 to 13, wherein the high-pressure piston (28) has a seal (40) that works when the high-pressure piston (28) retracts, so that the high-pressure piston is suitable for drawing high-pressure fluid from the fluid storage tank (30).

15. A rotary tilting worktable (42) for moving a rolling mill stand of a rolling mill from an upright working orientation to an inclined switching orientation and rotating the rolling mill stand in the switching orientation to a switching position, wherein the rotary tilting worktable (42) has a switching device (10) according to any one of claims 1 to 14.

16. The rotary tilting table (42) according to claim 15, wherein the rotary tilting table (42) has a first hydraulic cylinder (44) for tilting the rolling mill stand between the working orientation and the switching orientation, a second hydraulic cylinder for rotating the rolling mill stand in the switching orientation, and a hydraulic unit for supplying the first hydraulic cylinder (44) and the second hydraulic cylinder, The hydraulic unit is suitable for supplying the low-pressure side of the hydraulic unit (20) of the switching device (10).

17. A system consisting of a rotary tilting table (42) according to any one of claims 15 or 16 and a rolling mill stand, The rolling mill stand comprises at least one roller (12), which is fixed to the roller shaft (14) in a rotationally fixed manner via a dynamic coupling so as to be able to transmit the rolling torque from the roller shaft (14) to the roller (12). The roller shaft (14) is conical and has a hole (15), wherein the hole (15) forms a shaft fluid pipeline in the roller shaft (14) so as to guide the high-pressure fluid through the roller shaft (14) and guide the high-pressure fluid radially outward to the roller (12), so as to release or reduce the dynamic coupling between the roller (12) and the roller shaft (14).

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