Patent Application
20250214126
The invention relates to a dissipator for damping vibrations in a roll stand, wherein the dissipator comprises a hydraulic inductor, a hydraulic resistor, and a hydraulic capacitor as hydraulic components. The hydraulic capacitor and the hydraulic inductor each have a hydraulic volume for receiving hydraulic liquid. The roll stand is a roll stand for producing flat metallic rolled material, in particular hot-rolled metal strip, in which the necessary rolling force is generated by means of at least one so-called adjusting cylinder, which acts on one of the rolls (e.g. a supporting roll) of the roll stand.
A dissipator is a device that is coupled mechanically or fluidically to a vibrating system and conducts vibration energy out of the system in a passive manner, i.e., without active control, and thereby damps or entirely eliminates vibrations in the system. In contrast to actively controlled devices for vibration suppression, dissipators offer the advantage of a simpler mechanical construction, which is less subject to wear and allows a more compact design, owing to the avoidance of moving parts.
An adjusting cylinder of a roll stand is generally assigned a control valve, with the aid of which the rolling force of the roll stand is set, for example in the form of a servo valve for a hydraulic control circuit of the adjusting cylinder, wherein the control valve can be connected to the adjusting cylinder via a hydraulic interface of the adjusting cylinder. The hydraulic interface is used to conduct hydraulic liquid into and out of a piston-side pressure chamber of the adjusting cylinder. It can also be provided to conduct hydraulic liquid into and out of a ring-side pressure chamber of the adjusting cylinder via the hydraulic interface of the adjusting cylinder: in an adjusting cylinder that is designed to act on both sides, this takes place, for example, via the same control valve, which also controls the flow of hydraulic liquid into and out of the piston-side pressure chamber. In the case of an adjusting cylinder that is designed to act on one side, the pressure of hydraulic liquid in the ring-side pressure chamber thereof is held at a constant pressure level of 30 bar, for example, with the aid of a further pressure valve, wherein the hydraulic connection between the further pressure valve and the ring-side pressure chamber can likewise be guided via the hydraulic interface of the adjusting cylinder. Both with an adjusting cylinder that is designed to act on one side and with an adjusting cylinder that is designed to act on both sides, the generated rolling force results from the difference between the piston-side and the ring-side pressure chambers and can be set to a desired value with the aid of the assigned control valve.
Generally, a so-called valve block is provided, in which the control valve and where applicable the further pressure valve for the ring-side pressure chamber are embedded, and which is connected detachably as a hydraulic module to the hydraulic interface of the adjusting cylinder. A ‘detachable’ hydraulic connection between two hydraulic components or modules is understood below to mean a reversible mechanical-fluidic connection using connection means such as screw connections, so that the two connected components or modules can be disconnected from one another again non-destructively.
A rolling mill train comprising multiple roll stands for producing flat rolled material (e.g. metallic strips) can be designed as a simple hot-or cold-rolling mill train or as a combined casting and rolling plant (so-called ESP plant). In particular, a large number of undesirable vibrations can occur in such a rolling mill train during the rolling of metallic strips with a final thickness of less than or equal to 1 mm, which vibrations can sometimes reduce the lifetime or service life of individual components of a roll stand affected thereby, have a negative effect on the production rate thereof, or have a negative influence on the quality of a metal strip processed in the roll stand in question.
In particular self-excited vibrations are often inherent in the system, i.e., they occur unavoidably with certain constellations of certain production parameters, which are generally not known, however, and for this reason it is generally difficult to impossible to predict the occurrence of such vibrations. Examples of such production parameters that can cause or promote self-excited vibrations are a high rolling speed or a large thickness reduction at the roll stand in question. Self-excited vibrations in roll stands for rolling metal strips often occur in a frequency range of 70 to 130 Hz.
To reduce pressure vibrations in a hydraulic system of a roll stand of a cold- or hot-rolling mill train, AT 507 087 B1 discloses determining an alternating component of the pressure vibrations and supplying it to a control device, which, in real time, changes a resonator volume of a tuned mass damper in the form of a dissipator connected to the hydraulic system, depending on the determined alternating component. Here, it is proposed as a constructive solution to design the tuned mass damper as a λ/4 or Helmholtz resonator, which is connected to a hydraulic valve and a hydraulic cylinder of a hydraulic roll adjustment system. However, AT 507 087 B1 does not disclose any details of the constructive design and spatial arrangement of the dissipator on the roll stand.
WO 2020/239589 A1 also discloses a hydraulic vibration damper in the form of a dissipator, which has a frequency-dependent damping effect, which is tuned to a characteristic vibration frequency to be damped of the roll stand. According to a first exemplary embodiment, the vibration damper is fluidically connected directly to a hydraulic drive unit for a supporting roll of a roll stand but is fluidically not directly linked to a control valve that controls the fluid pressure in the hydraulic drive unit. According to a second exemplary embodiment, the vibration damper is fluidically linked to the hydraulic drive unit and the associated control valve via a T-piece.
The object of the invention is therefore that of overcoming the disadvantages of the dissipators known from the prior art and specifying a constructive solution that eliminates undesired pressure fluctuations of a characteristic vibration frequency in a hydraulic circuit of a roll stand as closely as possible to an adjusting cylinder while allowing the most compact design possible, and in which additional hydraulic lines and deflections are largely avoided.
This object is achieved according to the invention by a dissipator according to the independent claims. Preferred embodiments of the dissipator according to the invention form the subject matter of the dependent claims.
The dissipator according to the invention has a frequency-dependent damping effect that is tuned to a characteristic vibration frequency of the roll stand. This means that a design frequency of the dissipator differs by no more than 10% from a characteristic vibration frequency of the roll stand. On the one hand, the damping effect is achieved in that some of the vibration energy from the hydraulic circuit to be damped is transmitted into the dissipator itself: specifically, the hydraulic capacitor and the hydraulic inductor of the dissipator receive some of the input vibration energy, which is also referred to as the ‘tuned mass damper effect’ of the dissipator. Specifically, the pressure fluctuations from the adjusting cylinder are mostly displaced into the hydraulic volume of the dissipator, where they can have a higher amplitude corresponding to its design but are not disruptive. The tuned mass damper effect can thus be utilized advantageously to displace most of the undesired pressure fluctuations spatially out of the system to be damped (adjusting cylinder) into the hydraulic volume of the dissipator, without these pressure fluctuations actually having to be reduced (damped away).
Furthermore, the tuned mass damper effect means that the vibration behavior of the damped system is changed to the effect that the characteristic vibration frequency disappears, but two new vibration frequencies occur close to the original, characteristic vibration frequency. The (unfavorable because theoretically unlimited) resonance behavior of these newly occurring vibration frequencies can however be limited to a comparatively small and in any case harmless resonance behavior by adding a dissipative element to the dissipator (for example in the form of a hydraulic resistor). In this case, only a relatively small portion of the vibration energy introduced into the dissipator is reduced by the dissipative element thereof and converted into heat energy.
The damping effect of the dissipator resulting overall consequently depends on its tuned mass damper effect (by corresponding design of the hydraulic capacitor and inductor of the dissipator) and on the choice of hydraulic resistor. In addition, the damping effect of the dissipator extends substantially to a certain frequency band within the range of the design frequency of the dissipator, owing to the effect of the dissipative element thereof. The strength of the damping effect together with the frequency curve thereof is defined by the size of the hydraulic resistor. The tuning of the design frequency of a dissipator to a characteristic vibration frequency of the dissipator results from corresponding structural dimensioning of the hydraulic components thereof in conjunction with further hydraulic components of a hydraulic network to which the dissipator is fluidically coupled, and is known, for example, from the book “Grundlagen der Fluidtechnik—Teil 1: Hydraulik” (1st edition 1997) by Prof. Dr. H. Murrenhoff, in particular chapters 2.3.1 to 2.3.4 of said book.
Furthermore, the dissipator according to the invention has an intermediate piece, which can be fluidically arranged between an adjusting cylinder of the roll stand and a valve block having a control valve assigned to the adjusting cylinder. The intermediate piece has a first hydraulic interface within the aforementioned meaning for direct hydraulic-mechanical linking of the dissipator to the adjusting cylinder of the roll stand. For this purpose, the first hydraulic interface of the intermediate piece has both passage openings as connection points for hydraulic lines and optionally corresponding sealing means as well as devices for mechanical connection means (such as threads or fit bores for screws), by means of which the intermediate piece can be coupled hydraulically to the adjusting cylinder. As a result, hydraulic liquid can pass between the intermediate piece and the adjusting cylinder in both directions, and the intermediate piece can be connected mechanically to the adjusting cylinder. This therefore also allows a direct mechanical fastening of the intermediate piece to the adjusting cylinder.
Direct hydraulic-mechanical linking of a first hydraulic component or module to a further hydraulic component or module within the context of the invention means a direct fluidic and mechanical coupling of the first to the further hydraulic component or module without interposition of further fluidic or mechanical connection elements, wherein a direct passage of liquid from the first to the further hydraulic component or module and vice versa is made possible.
The direct hydraulic-mechanical linking of the dissipator according to the invention to the adjusting cylinder of a roll stand is implemented in that one of the hydraulic components thereof, for example the hydraulic inductor, is directly fluidically coupled via the first hydraulic interface to the adjusting cylinder. The advantage of this is the resulting compact design of the dissipator. In addition, this also avoids undesired reflections of pressure waves and parasitic hydraulic inductances and capacitances, which otherwise arise as a result of additional fluidic connection pieces (such as T-pieces), connection lines or hydraulic deflections.
The intermediate piece of the dissipator according to the invention additionally has a second hydraulic interface for hydraulic linking of the valve block, for example via one or more hydraulic connection lines, to the dissipator. By means of the first and second hydraulic interfaces, the intermediate piece provides the hydraulic ports or connection lines between the control valve (and where applicable the pressure valve for the ring-side pressure chamber of the adjusting cylinder) and the adjusting cylinder, so that the functionality of the valve block with respect to the adjusting cylinder is not changed by the attachment of the intermediate piece to the adjusting cylinder.
By means of the fluidic arrangement of the intermediate piece between the adjusting cylinder and the valve block, the dissipator according to the invention can be arranged in a space-saving manner on the roll stand. In addition, apart from the desired damping effect on undesired vibrations, the dissipator according to the invention behaves particularly neutrally with respect to the hydraulic behavior of the roll stand, since the hydraulic line routes between the adjusting cylinder and the valve block with the control valve are changed only minimally by the installation of the dissipator.
Furthermore, owing to the first and second hydraulic interfaces, an already existing roll stand can be retrofitted with the dissipator in a simple manner without constructive changes having to be carried out on the roll stand itself. The dissipator valve block with the control valve can also be spatially remote from the adjusting cylinder and connected thereto only via corresponding hydraulic lines. At most, fastening devices for the intermediate piece of the dissipator must be attached to the adjusting cylinder, and/or existing hydraulic lines must be minimally adapted.
It is also known that undesired vibrations, caused for example by natural vibrations within the set of rolls in a roll stand, generally result in pressure fluctuations in the piston-side pressure chamber of an adjusting cylinder of the roll stand, which are then transmitted into the connected hydraulic circuit. By directly hydraulically linking the dissipator according to the invention to the adjusting cylinder, undesired pressure fluctuations in the associated hydraulic circuit are damped away as close as possible to the starting point of the vibrations (the piston-side pressure chamber of the adjusting cylinder), so that they do not propagate further into the connected hydraulic circuit. This avoids damage to line elements of the hydraulic circuit or subassemblies of the roll stand in question, such as bearings, gears and drive shafts, as well as roll surfaces.
According to a development of the dissipator according to the invention, the second hydraulic interface is designed for direct hydraulic-mechanical linking of the valve block to the dissipator within the above-described meaning. This embodiment of the dissipator according to the invention is particularly advantageously suitable as a space-saving retrofitting solution for a roll stand in which a valve block with a control valve assigned to the adjusting cylinder of the roll stand is already fastened directly to the adjusting cylinder and which is directly hydraulically-mechanically linked via a respective hydraulic interface of the adjusting cylinder and of the valve block within the above-defined meaning.
In this embodiment, the first hydraulic interface of the intermediate piece is identical to the hydraulic interface of the valve block and allows direct hydraulic-mechanical linking of the intermediate piece or the dissipator to the adjusting cylinder. The second hydraulic interface of the intermediate piece is again identical to the hydraulic interface of the adjusting cylinder and allows direct hydraulic-mechanical linking of the valve block to the intermediate piece or to the dissipator. The intermediate piece thereby functions as a mechanical fastening seat for the valve block with the control valve.
According to a further preferred embodiment of the invention, the hydraulic resistor of the dissipator is formed as an adjustable valve. The adjustable valve can be designed, for example, as a butterfly valve with an adjustable cross section for the liquid flow conducted through it. Since the strength of the damping effect of the dissipator is defined by the dissipative element thereof, a suitable choice of the hydraulic resistance value can achieve an optimal damping effect, which is largely independent of the vibration frequency within the frequency band to which it extends and with which it is ensured that as much vibration energy as possible is directed out of the system to be damped.
The damping effect of a dissipator depends primarily on its design frequency and to a certain extent also on the peripheral hydraulic connection lines of the system to be damped, to which lines the dissipator is connected when installed on the roll stand. It is therefore advantageous, in particular during commissioning, when the hydraulic resistance value in the form of an adjustable valve can be set, in the installed state of the dissipator, to a value that corresponds to the optimal damping effect.
The adjustable valve can be electrically adjustable. It is thereby possible to change the damping effect of the dissipator in the installed state also subsequently in a simple manner, for example by means of plant automation, and adapt it to a changed characteristic vibration frequency of the roll stand. The characteristic vibration frequency can be influenced slightly for example by a roll change or owing to changed production parameters such as rolling speed, strip thickness or the set rolling force of the roll stand.
Furthermore, the adjustable valve can be completely closed. The dissipator can thereby also be deactivated when installed on the roll stand, since no more vibration energy can be reduced with the valve completely closed.
In a further preferred embodiment of the invention, the dissipator has a design frequency in a range of 70 Hz to 130 Hz. In this case, the hydraulic resistor is designed as a valve that is designed for a maximum flow rate of hydraulic liquid of 300 liters per minute and a maximum differential pressure of 5 bar. The undesired vibrations of the roll stand cause pressure fluctuations in the hydraulic circuit of the relevant adjusting cylinder and are transmitted to the directly hydraulically-mechanically linked dissipator. The maximum differential pressure is the pressure difference that arises between the input-side and output-side valve connections without the valve being damaged. The hydraulic inductor is designed as a tubular cavity with a length of 600 mm to 800 mm and a largest diameter of 50 mm to 65 mm. The hydraulic capacitor of the dissipator according to the invention is designed as a pressure vessel for a maximum pressure of 300 bar with a volume of 10 to 20 liters.
A ‘tubular cavity’ in this case means a cavity having a certain length along a longitudinal direction and a cross-sectional shape that stays the same along the longitudinal direction. The cross-sectional shape extends normally to the longitudinal direction and has a largest diameter that corresponds to the diameter of a circumscribed circle around the cross-sectional shape. Furthermore, the length of the tubular cavity is at least twice its largest diameter. A tubular cavity can thus be designed in the simplest case as a cylindrical bore, but generally also as a prismatic cavity or as a cavity with a cross section of any desired shape. A first and a second end face delimit the tubular cavity at its respective ends in the longitudinal direction.
The design of the dissipator according to the invention with the stated dimensions represents a good compromise between the damping effect of the dissipator and its structural implementation for damping undesired vibrations in a roll stand in the stated frequency range: this is because, to achieve a good damping effect over the largest possible frequency range, the volume of the hydraulic capacitor should be selected to be as large as possible. However, upwards of a certain size of the pressure vessel of the hydraulic capacitor, it would no longer be possible to attach the dissipator to an adjusting cylinder of a roll stand for space reasons; in addition, the procurement costs for such a pressure vessel rise disproportionately with increasing volume.
Furthermore, a predominantly inductive nature of the tubular cavity would no longer be present with a length of less than 600 mm, since the cross-sectional area or the necessary largest diameter of the tubular cavity for the stated frequency range would be so large that the tubular cavity would also have hydraulically capacitively acting components. Finally, a hydraulic inductor having a tubular cavity with a length greater than 800 mm would not be feasible in a structurally compact manner and would result in unfavorable mechanical loading at the connection of the dissipator to the adjusting cylinder.
According to a further preferred embodiment of the dissipator according to the invention, the hydraulic capacitor has a further pressure vessel, which is directly hydraulically-mechanically linked to the hydraulic capacitor within the above-defined meaning. The further pressure vessel has a clampable adjusting device, by means of which the hydraulic volume of the additional pressure vessel can be set to a value between 0% and 30% of the hydraulic volume of the pressure vessel of the hydraulic capacitor.
The size of a hydraulic capacitor is proportional to its hydraulic volume. By means of the direct hydraulic-mechanical linking of the further pressure vessel to the hydraulic capacitor of the dissipator, its effective volume, and thus its hydraulic capacitance value, is increased. The frequency band of the damping effect of the dissipator and its design frequency can thereby also be adapted flexibly, in the installed state, to a vibration frequency to be damped of the roll stand. The adjusting device can have, for example, a piston that is mounted displaceably within the first pressure vessel and is moved into a desired position via a further hydraulic adjustment valve and thereby sets the hydraulic volume of the additional pressure vessel.
An essential property of the adjusting device is its clampability: this means that the adjusting device can be locked such that the hydraulic volume of the further pressure vessel does not change even with a maximum expected pressure amplitude within the dissipator or within its hydraulic capacitor. The clampable adjusting device can be, for example, a piston that is mounted displaceably within the further pressure vessel and has a piston rod that can be clamped in a desired displacement position of the piston by means of a clamping device.
Preferably, the clamping device is designed to hold the piston rod in the desired position without further energy supply. This means that the clamping device does not have to be supplied with any electrical or mechanical energy to keep the piston rod in the set position even when there is constant or alternating axial loading of the clamped piston rod, in particular owing to pressure waves in the dissipator caused by an undesired vibration frequency of the roll stand.
For this purpose, the clamping device can comprise energy-saving mechanical holding elements, which are shifted by the supply of mechanical energy into an open position in which the piston rod is not clamped and is therefore freely displaceable, and wherein the holding elements can also be made to reduce the absorbed mechanical energy and in the process enter into a frictional connection with the piston rod so that the piston rod is clamped in a desired position. The supply of mechanical energy or the opening of the holding elements can take place, for example, by applying hydraulic pressure to the clamping device, wherein a subsequent reduction of the applied hydraulic pressure to below a certain lower threshold value causes the holding elements to clamp the piston rod.
The advantage of such a design of the clamping device is the fact that energy must be applied only briefly to adjust the frequency band of the damping effect or the design frequency of the dissipator, but the clamping device can remain in the non-energized state for most of the time. This ensures that the design frequency of the dissipator or its damping effect does not change even in the event of a failure of the energy supply or the hydraulic supply pressure on the roll stand in question.
In a further preferred embodiment of the invention, the intermediate piece with the first and second hydraulic interfaces is designed as a rigid block, for example as a metal block. The hydraulic resistor and the hydraulic capacitor of the dissipator are fluidically connected detachably to the rigid block within the aforementioned meaning. Furthermore, the hydraulic inductor is fluidically connected to the hydraulic resistor or to the hydraulic capacitor so that the hydraulic inductor, the hydraulic resistor and the hydraulic capacitor of the dissipator are fluidically coupled to one another in series via the rigid block. This means that the hydraulic inductor, the hydraulic resistor and the hydraulic capacitor are fluidically connected to one another and are arranged fluidically one behind the other.
Furthermore, the hydraulic inductor is made in the intermediate piece as a tubular cavity. Furthermore, the tubular cavity is fluidically connected to the first and second hydraulic interfaces of the intermediate piece. In order to avoid undesired reflections of pressure waves at the hydraulic inductor or to keep them as small as possible, the ratio between the cross-sectional area of the tubular cavity of the hydraulic inductor in the rigid block and the cross-sectional area of the respective fluidic passage opening in the first and second hydraulic interfaces is preferably in a range between 4 and 1. In other words, the cross-sectional area of the fluidic passage opening to the adjusting cylinder or to the valve block is in each case 25% to 100% of the cross-sectional area of the hydraulic inductor in the rigid block.
The design of the intermediate piece as a rigid block allows a particularly stable integration of the hydraulic components of the dissipator, in which a stable mechanical connection of the hydraulic capacitor and of the hydraulic resistor to the intermediate piece is made possible via screw connections, for example. Furthermore, with a design of the intermediate piece as a rigid block, parasitic hydraulic capacitances or inductances in the dissipator itself are largely avoided, since, because of the compact mechanical and hydraulic linking of the individual hydraulic components to one another, no further fluidic connection pieces are needed therebetween. As a result, a desired design frequency of the dissipator can be complied with, with a high degree of accuracy.
Moreover, a design of the intermediate piece as a rigid block together with a series coupling of the hydraulic components allows a space-saving formation of the dissipator, which can advantageously be adapted to the available space conditions on the roll stand: for instance, the largest longitudinal dimension of the intermediate piece can extend in the direction of the tubular cavity for the hydraulic inductor and can be a multiple of, for example three or five times, the smallest longitudinal dimension that extends normally thereto between the first and second hydraulic interfaces for the adjusting cylinder and for the control valve, respectively. For an installation of the dissipator according to the invention in the roll stand, this results in a relatively small space requirement between the control valve and the adjusting cylinder, while in a direction normal thereto, an empty volume that is generally present on the roll stand can advantageously be utilized.
In a preferred embodiment of the dissipator according to the invention, the hydraulic resistor thereof is implemented in the form of a so-called poppet valve or cartridge valve. Such a valve comprises an installation part, through which the hydraulic liquid is conducted. The installation part can be sunk (within the meaning of spatially introduced and connected) entirely in a further hydraulic component, for example in the intermediate piece of the dissipator according to the invention, so that, in the part of the cartridge valve remaining outside the further hydraulic component, no guidance of hydraulic liquid takes place, but actuators and/or control electronics of the valve, for example, are accommodated. By means of this design, short hydraulic line routes through the hydraulic resistor can advantageously be implemented, and disruptive effects (such as reflections of pressure waves in the interior of the hydraulic resistor) are avoided.
A flow of hydraulic liquid is conducted through the cartridge valve in the dissipator, wherein vibration energy of the system to be damped is dissipated by the cartridge valve. The cartridge valve is designed to deflect the conducted flow of hydraulic liquid at a right angle and in the process to connect the hydraulic inductor of the dissipator fluidically to its hydraulic capacitor. The cartridge valve can be designed as an infinitely variable proportional valve with a controllable opening position between 0 and 100% of a maximum opening position. Furthermore, the cartridge valve can be configured to report the set opening position. The set opening position of the proportional valve can, for example, correspond to a current position of a piston in the proportional valve: in this case, the current position of the piston can, for example, be reported as a measure of the opening position of the proportional valve.
A cartridge valve of the stated type offers the advantage that the conducted flow of hydraulic liquid undergoes only a single deflection by 90°. In contrast to this, a conducted flow of hydraulic liquid undergoes a multiple deflection in so-called mounted valves: once in order to be introduced into the mounted valve from a supplying hydraulic line, then a deflection by 180° takes place in the mounted valve itself, and then the liquid flow is deflected in direction again on reintroduction into the hydraulic line. Such deflections are disadvantageous in a hydraulic component, since they can result in undesired reflections and turbulence of the conducted flow of hydraulic liquid.
Furthermore, because of the 90° deflection of the conducted flow of hydraulic liquid, a described cartridge valve allows a compact mechanical construction of the dissipator according to the invention, in which its hydraulic capacitor is arranged closer to the first hydraulic interface than would be the case if a conventional mounted valve were used. As a result, the first hydraulic interface of the dissipator is loaded less during its installation, i.e., during direct hydraulic linking for example to an adjusting cylinder of a roll stand.
According to a further preferred embodiment of the invention, the dissipator comprises a cover cap that can be mechanically detached from the rigid block of the intermediate piece and forms an end face of the tubular cavity forming the hydraulic inductor in the intermediate piece and thereby delimits the hydraulic inductor at one end. This design allows particularly exact dimensioning of the hydraulic inductance value with which the tubular cavity can be made for example as a bore in the rigid block of the intermediate piece and is closed with the cover cap. In addition, the cover cap can also have a tubular insert, which delimits the volume of the made tubular cavity in a defined manner: the hydraulic inductance can thereby also be set subsequently to a changed value depending on the dimensions of the tubular insert.
The above-described properties, features and advantages of the invention and the manner in which these are achieved become clearer and more easily understandable in connection with the following description of the exemplary embodiments of the invention, which are explained in more detail in connection with the figures. In the figures,
The control valve 11 and the pressure valve 12 are connected to further hydraulic lines (not shown in
The control valve 11 is arranged in a valve block 6, which is directly hydraulically-mechanically linked to an intermediate piece 20 of a dissipator 1 according to the invention. For this purpose, the intermediate piece 20 has, on the valve block side, in each case two fluidic passage openings 33, 34 corresponding to the piston-side and ring-side pressure chambers 7, 8 and is mechanically connected to the intermediate piece 20 via connection means 29 (not shown in
The fluidic passage openings 32 and 34 corresponding to the ring-side pressure chamber 8 are connected to one another only fluidically via a simple bore 36 inside the intermediate piece. In contrast, the fluidic passage openings 31 and 33 corresponding to the piston-side pressure chamber 7 are both fluidically connected to one another and fluidically linked to the hydraulic components of the dissipator 1 inside the intermediate piece. This is shown symbolically in
Pressure fluctuations 16 caused by the roll stand in the piston-side pressure chamber 7 are largely damped away by the dissipator 1, so that the control valve 11 and hydraulic lines connected thereto or further hydraulic units are subject at most to greatly attenuated pressure fluctuations 16′.
The dissipator 1 shown in
The hydraulic resistor 22 is implemented as a cartridge valve 22′, which is designed to deflect a conducted flow of hydraulic liquid at a right angle to the second longitudinal axis 27. Furthermore, the hydraulic resistor 22 is fluidically connected to a hydraulic capacitor 23, which is designed as a cylindrical fluid chamber for receiving hydraulic liquid and is fastened to the intermediate piece 20 in the direction of its cylinder axis perpendicularly to the second longitudinal axis 27. The hydraulic capacitor 23 has a predefined volume of 10-20 liters and is filled with hydraulic liquid during the operation of the dissipator 1. The hydraulic resistor 22 and the hydraulic capacitor 23 are each detachably connected fluidically to the intermediate piece 20. In the arrangement shown in
In the intermediate piece 20 of the exemplary embodiment shown, a bore 36 is also made, which fluidically connects the second fluid line 14 of the adjusting cylinder 2 via fluidic passage openings 32 and 34 to the control valve 11 and pressure valve 12 (not shown in
Fit bores 29 are made in the intermediate piece 20 for receiving screws 30, with the aid of which the intermediate piece 20 can be fastened to the cylinder housing 3 of the adjusting cylinder 2 (not shown in
At the fluidic passage openings 31 and 32, recesses 38 for annular sealing means 37 are also made in the intermediate piece 20 in order to prevent the escape of hydraulic liquid conducted through the intermediate piece 20 on passing into the first and second fluid lines 13 and 14 of the adjusting cylinder 2. For the same purpose, annular sealing means 37 can be arranged at the fluidic passage openings 33 and 34 between the intermediate piece 20 and the valve block 6 (not shown in
The threaded bores 25 have an offset 40 along the Z axis relative to the fit bores 29. Likewise, the valve-block-side fluidic passage openings 33 and 34 have the same offset 40 along the Z axis relative to the corresponding cylinder-side passage openings 31 and 32. This offset arrangement of screws 30 relative to further screws 30′ and of fluidic passage openings 31 and 32 relative to corresponding fluidic passage openings 33 and 34 means that the dissipator 1 according to the invention can be installed subsequently between an adjusting cylinder 2 and a valve block 6 connected hydraulically thereto, without changes having to be made to the hydraulic interfaces of the adjusting cylinder 2 or of the valve block 6.
Furthermore, the hydraulic capacitor 23 has a clampable adjusting device 45, which comprises: a piston 46, which is mounted displaceably inside the further pressure vessel 41 and has a piston rod 47; a hydraulic clamping device 48 for clamping the piston rod 47; a hydraulic adjustment valve 49 for moving the piston 46; and a hydraulic pressure valve 50 for opening the clamping device 48.
The clamping device 48 can be operated in a so-called ‘non-energized’ state, in which the piston rod 47 is held in a position by the clamping device 48 and in which the clamping device 48 is not loaded with any hydraulic pressure or supplied with any electrical energy. The clamping force for the piston rod 47 is applied by energy-saving mechanical holding elements: in the exemplary embodiment shown in
By activation of the pressure valve 50, a hydraulic pressure chamber 54 opposite the compression spring 53 is loaded with pressurized hydraulic liquid, and the press fit 52 is displaced against the compression spring 53, so that the clamping of the conical seat 51 is undone. In addition, mechanical energy is absorbed by the compression spring 53 as a result of the displacement of the press fit 52. Via the hydraulic adjustment valve 49, the piston 46 can then be moved into a desired position, wherein the hydraulic volume in the further pressure vessel 41 between the fluidic passage opening 44 and the piston 46 can be set to a value between 0% and 30% of the hydraulic volume of the cylindrical fluid chamber 43. As soon as the piston 46 has reached the desired position, the pressure in the hydraulic pressure chamber 54 can be reduced to a value below a lower threshold value by deactivating the pressure valve 50, so that the force of the compression spring 53 predominates and this presses the press fit 52 against the conical seat 51 owing to the previously absorbed mechanical energy, so that the conical seat locks the piston rod 47 again.
| Number | Date | Country | Kind |
|---|---|---|---|
| 22164699.5 | Mar 2022 | EP | regional |
The present application is a national phase application of PCT Application No. PCT/EP2023/057266, filed Mar. 22, 2023, entitled “CONSTRUCTIVE DESIGN AND ARRANGEMENT OF A DISSIPATOR FOR SUPPRESSING VIBRATIONS IN A ROLL STAND”, which claims the benefit of European Patent Application No. 22164699.5, filed Mar. 28, 2022, each of which is incorporated by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2023/057266 | 3/22/2023 | WO |
