EP3610961B1 - Device, rolling mill and method for regulating strip tension during the flexible rolling of metal strips - Google Patents

Description

The invention relates to a device, a rolling plant with such a device and a method for controlling strip tension during flexible rolling of metal strip, the device having a roller arrangement with at least one dancer roller whose position can be adjusted to control the strip tension of the metal strip. Furthermore, the device has at least one hydraulic drive, which is coupled to the dancer roll for adjusting the latter, and a hydraulic tank for hydraulic fluid, which is connected to the hydraulic drive via a hydraulic supply line in a fluid-conducting manner. A controllable valve arrangement is arranged between the hydraulic tank and the hydraulic drive for controlling the hydraulic drive. The hydraulic drive is supplied with hydraulic fluid from the hydraulic tank by means of a hydraulic pump. The device also includes at least one hydraulic pressure accumulator for temporarily storing hydraulic fluid previously delivered by the hydraulic pump, the hydraulic pressure accumulator being arranged between the hydraulic pump and the valve arrangement.

A device of the type mentioned is in the GB 1 165 475 A shown. In the device shown there, the valve arrangement is transferred to a neutral position during the rolling process, in which both chambers of the hydraulic cylinder for moving the roll are connected to the pressure accumulator. A constant pressure is thus applied to the hydraulic cylinder and the roller is pressed against the belt with a constant force. The force exerted by a piston rod of the hydraulic cylinder depends on the difference between a force on the piston rod side Surface and a cylinder chamber side surface of a piston of the hydraulic cylinder.

So-called flexible rolling produces metal strips with periodically changing, defined different thicknesses. The length and thickness of the rolled longitudinal thickness profile corresponds, for example, to the subsequent load case of a sheet metal component. The rolling process can be designed as cold or hot strip rolling. The strip material to be rolled is unwound from a coil, rolled and then wound up again under tension. The corresponding rolling mills can be reversing mills, i. H. after a coil has passed from a first to a second coiling device, a next coil can be allowed to pass from the second to the first coiling device. After appropriate post-treatment, circuit boards are separated from this strip material and used for the production of components with different wall thicknesses.

With flexible rolling, serious strip thickness differences of up to 50% and more are achieved in a single rolling pass (pass) by changing the roll gap using servo-hydraulic or servo-electric adjustment means for the work rolls. A change in the roll gap and thus the exiting strip thickness results from the condition of constant volume at the roll gap, resulting in changes in the strip speed on the entry and exit sides. Due to these changes in speed, the strip tension of the metal strip also changes constantly. The changes in the strip speed and thus the strip tension take place so quickly at high rolling speeds that the coiling devices are not able to maintain constant strip tensions at the roll gap by adjusting the coiling speeds. Changes in the strip tension have a direct impact on the strip thickness tolerances on the outlet side. In order to improve the strip thickness tolerances, a method is therefore required that enables constant strip tensions even over strongly varying strip speeds. To this end, so-called dancers have been used in the strip line for decades, which in their function as strip storage means keep the strip tension constant when the speed changes.

One way the speed variation of the metal strip at relatively to compensate for low rolling speeds is to change the coiler speeds. Here, the speed of the reel is regulated depending on the position of the roll gap. If the roll gap opens and a thicker area is rolled, the speed of the coiler increases. If the roll gap is closed and the strip speed is reduced as a result of the process, the coiler speed is also reduced, as shown in the CN 101890434A is described. The disadvantage of this method is the limitation of the coil weight and the rolling speed. Due to the mass inertia, the response time of the system increases with increasing mass. An increase in the mass of the coil leads to a necessary reduction in the rolling speed. On the other hand, an increased rolling speed causes a reduction in the mass of the coil, which increases the non-productive times of the plant.

DE 103 15 357 A1 discloses a rolling mill for rolling metal strip with a first coiling device for uncoiling, from which strip with a defined initial strip thickness can be unwound, with a roll stand that comprises at least two work rolls, between which a roll gap that can be controlled and/or regulated in terms of width is formed, and with a second coiling device for coiling, onto which metal strip with a reduced strip thickness compared to the defined initial strip thickness can be wound up. Furthermore, the rolling installation has first strip storage means with a roller arrangement made up of a plurality of rollers between the first coiling device and the rolling stand. The rolling installation also has second strip storage means with a roller arrangement made up of a plurality of rollers between the rolling stand and the second coiling device. The position of the rollers of the first tape storage means and the second tape storage means can be changed relative to one another for tape storage, the metal tape being guided in the form of an "S" with at least partially superimposed arcs. To change the position of the rollers relative to one another, the movement of one of the rollers per strip storage means is adjusted hydraulically so that the "S" is distorted such that the length of the metal strip between an entry and an exit in the respective strip storage means is changed.

From the EP 1 121 990 B2 is a device for rolling metal strips with periodically changing strip thickness is known, in which a compensating or dancer roll is arranged both between a coiler for uncoiling metal strip and the roll stand and between the roll stand and a coiler for coiling metal strip. The strip material is looped around the compensating or dancer roll. The compensating or dancer rolls are force-controlled at a constant peripheral speed of the rolls of the roll stand that determine the roll gap in order to apply a desired strip tension, with the reels being speed-controlled. The compensating or dancer rolls are adjusted vertically and linearly in a direction perpendicular to the metal strip.

The object of the present invention is to provide a device, a rolling installation and a method for controlling strip tension during flexible rolling of metal strip, in which rapid and precise regulation of strip tension in the metal strip is made possible.

The object is achieved by a device for controlling strip tension during the flexible rolling of metal strip, the device having the following: a roller arrangement with at least one dancer roller, the position of which can be adjusted to regulate the strip tension of the metal strip, at least one hydraulic drive which is used to adjust the Dancer roller is coupled to this, a hydraulic tank for hydraulic fluid, which is connected to the hydraulic drive via a hydraulic supply line, a controllable valve arrangement between the hydraulic tank and the hydraulic drive for controlling the hydraulic drive, a hydraulic pump, with which the hydraulic drive is supplied with hydraulic fluid from the Hydraulic tank is supplied, and at least one hydraulic pressure accumulator for temporarily storing hydraulic fluid previously delivered by the hydraulic pump, the hydraulic pressure accumulator being arranged between the hydraulic pump and the valve arrangement. A pressure sensor for determining the hydraulic pressure is arranged in the hydraulic drive, the device being set up to infer the strip tension in the metal strip from the hydraulic pressure and to control the valve arrangement as a function of the determined strip tension.

Rapid adjustment of the at least one dancer roll is particularly at high rolling speeds, for example over 25 m/min, and when using large coil masses of, for example, 5 to 25 kg/mm strip width with strip widths of 300 to 750 mm, not just by adjusting the To ensure delivery capacity of the hydraulic pump. The invention therefore also provides a hydraulic pressure accumulator for temporarily storing hydraulic fluid previously delivered by the hydraulic pump, the hydraulic accumulator being arranged between the hydraulic pump and the valve arrangement. A high volume of hydraulic fluid for adjusting the at least one dancer roll can be made available from this hydraulic pressure accumulator in a very short time, so that small fluctuations in the strip tension, if possible below 35%, can be achieved. The hydraulic pressure accumulator is to be arranged as close as possible to the hydraulic units for adjusting the dancer roll, so that line losses between the hydraulic pressure accumulator and the adjusting unit for the dancer roll are kept low.

The hydraulic drive can be, for example, one or more hydraulic cylinders per dancer roll. One double-acting hydraulic cylinder or two single-acting hydraulic cylinders can be used to adjust a dancer roll.

The hydraulic pressure is measured in the hydraulic supply line or in one or more cylinder chambers of the hydraulic cylinder.

In addition, it is possible for at least one force sensor, for example a tension measuring cell, to be arranged on at least one roller of the roller arrangement in order to determine the forces acting on the respective roller or rollers from the metal strip. Thus, the strip tension in the metal strip can be directly inferred.

Furthermore, a path measuring system for determining the position of the dancer roll can be arranged on the at least one dancer roll. This makes it possible to determine whether the dancer roll is already in the vicinity of an end position of its adjustment path to be able to adjust the speed of the metal strip if necessary. The speed of the metal strip can be adjusted by changing the reel speed. Changing the speed of the metal strip tends to shift the position of the dancer roll.

According to one embodiment of the device according to the invention, the hydraulic drive is connected in a fluid-conducting manner to the hydraulic tank via a return, with at least one pulsation damper being arranged in the return. At high belt speeds, a high frequency of adjustment of the dancer roll is required, which leads to high flow velocities and possible cavitation in the hydraulic lines. These pressure fluctuations can be reduced by the at least one pulsation damper in order to prevent damage to the hydraulic system. Here, the at least one pulsation damper is arranged as close as possible to the hydraulic cylinder.

In addition, a compensating tank can be arranged downstream of the at least one pulsation damper, in order to enable further expansion of the hydraulic fluid as close as possible to the hydraulic drive. The flow of the hydraulic fluid, starting from the expansion tank to the hydraulic tank, can then be based purely on gravity, which counteracts further cavitation. A check valve can be arranged between the compensation tank and the hydraulic tank.

According to an exemplary embodiment, the dancer roll is arranged so that it can be adjusted horizontally. In principle, however, an adjustment direction of the dancer roll that deviates from the horizontal direction is also conceivable.

In addition to the at least one dancer roller, the roller arrangement can have at least one further roller, the at least one dancer roller and the at least one further roller being arranged vertically one above the other in such a way that the metal strip is guided in the shape of an S or as an S-shaped loop .

The task is further accomplished by a rolling mill for the flexible rolling of metal strip solved, wherein the rolling mill has the following: a roll stand with two work rolls between which a width-adjustable roll gap is formed, a first strip guiding unit with a first coiler for uncoiling metal strip, a second strip guiding unit with a second coiler for coiling rolled metal strip. In addition, in at least one of the strip guide units mentioned, a device according to the embodiments described above is arranged between the respective coiler and the roll stand.

Another solution to the problem is a method for controlling a strip tension during the flexible rolling of metal strip in a rolling mill with a device as described above, the valve arrangement being controlled as a function of the strip tension of the metal strip and the hydraulic drive being at least partially available for the short-term provision of hydraulic fluid is fed with hydraulic fluid previously stored in the at least one hydraulic accumulator.

The hydraulic pressure is measured in the hydraulic drive, the strip tension in the metal strip being inferred from the hydraulic pressure and the valve arrangement being controlled as a function of the strip tension determined.

In addition, the forces acting from the metal strip on a roller of the roller arrangement can be measured, with the strip tension in the metal strip being inferred from the determined forces and the valve arrangement being controlled as a function of the strip tension determined.

In one embodiment of the method for controlling a rolling mill as described above, the position of the dancer roll of the at least one strip guide unit can be determined using a position measuring system, with the speed or rotational speed of the reel of the at least one strip guide unit being controlled depending on the position of the dancer roll. This can be used to change the position of the dancer roll.

In the strip-guiding unit between the first coiler for uncoiling the metal strip and the roll stand, this can shortly before reaching a defined first End position of the dancer roll, in which the metal strip length between an entry into the roller arrangement and an exit from the roller arrangement assumes a minimum value, the speed of the first reel can be increased. The speed of the first reel can be reduced shortly before a defined second end position of the dancer roll is reached, in which the metal strip length between the entry into the roller arrangement and the exit from the roller arrangement assumes a maximum value. This avoids the dancer roll having to be adjusted beyond the two end positions and being kept in a central area as far as possible.

In the case of the strip-guiding unit between the roll stand and the second coiler for coiling the metal strip, the conditions are the opposite. This means that shortly before the dancer roller reaches a defined first end position, at which the metal strip length between an entry into the roller arrangement and an exit from the roller arrangement assumes a maximum value, the speed of the second reel is increased. Shortly before a defined second end position of the dancer roll is reached, at which the metal strip length between the entry into the roller arrangement and the exit from the roller arrangement assumes a minimum value, the speed of the second reel is reduced.

Furthermore, it can be provided that the roll gap setting of the roll stand is determined, the valve arrangement being controlled in addition to the strip tension of the metal strip as a function of the roll gap. This enables pre-control as a function of the roll gap setting, which, in particular in combination with the control from the determination of the strip tension, ensures a short response time of the system.

A preferred embodiment of a rolling mill according to the invention is explained in more detail below with reference to the drawings. The drawing shows a sketch of a rolling mill according to the invention with a hydraulic adjustment device in a side view.

A roll stand 2 is built on a foundation 1, in which two work rolls 3, 4 and two lying one above the other in vertical alignment with the work rolls 3, 4 lying support rollers 5, 6 can be seen. An adjustable and controllable roll gap 7 is formed between the work rolls 3, 4, through which a metal strip 8 runs from left to right in a production direction P in the illustration shown. The rolling installation can be a reversing installation in which, after a coil has passed through in the production direction P, as shown in the figure, a next coil runs through the rolling installation in the opposite direction.

In the exemplary embodiment shown, the metal strip 8 comes from a first reel device 9 with a left-hand rotating first reel 10 from which the metal strip 8 is unwound via the underside of the first reel 10 . From the first coiling device 9, the metal strip 8 runs in the production direction P into a first roller arrangement 11 for storing a specific length of the metal strip 8 and for introducing a strip tension into the metal strip 8 in the form of a double roller arrangement, which has a movable upper dancer roller 12 and a fixed lower roller 13 has. A horizontal double arrow indicates that the dancer roller 12 in the first roller arrangement 11 can be displaced horizontally in a controlled manner. In principle, other orientations, such as a vertical or oblique adjustment, and other forms of movement, such as a pivoting movement, are also conceivable. In the embodiment indicated here, a movement of the dancer roller 12 changes the length of the loop of the metal strip 8 between an entry into the first roller arrangement 11 and an exit from the first roller arrangement 11.

The lower roller 13, which is fixed per se, can be pivoted by means of a rocker 14 from its operating position (continuous representation 13) into an insertion position (dashed representation 13') via a band line 21. The dotted line indicates the insertion position of the stationary roll 13, in which the metal strip 8 can be introduced into the roll stand 2 along the strip line 21, which is also shown in dashed lines. When the metal strip 8 is fixed for reeling, the roller 13 pivots back into its operating position shown in solid line.

In the production direction behind the roll stand 2 and thus to the right of the roll stand 2, a second coiling device 15 for coiling the metal strip 8 is shown. which has a left-handed second reel 16 which winds up the rolled metal strip 8 via the underside. Between the roll stand 2 and the second coiling device 15 there is a further second roller arrangement 17 for storing metal strip and applying a strip tension, which has a movable upper dancer roller 18 and a fixed lower roller 19 .

In principle, the first reel 10 and the second reel 16 can be designed to rotate to the left or right, with the metal strip 8 being able to be wound up or unwound from above or from below.

A horizontal double arrow indicates that the dancer roller 18 can be displaced in a controlled manner in relation to the fixed roller 19 in the second roller arrangement 17 . It is also conceivable here, analogously to the dancer roller 12 of the first roller arrangement 11, that the dancer roller 18 is displaced or pivoted in a different direction. By adjusting the dancer roller 18 of the second roller arrangement 17, the length of the loop of the metal strip 8 between an entry into the second roller arrangement 17 and an exit from the second roller arrangement 17 is changed.

The broken line shows the roller 19 in an insertion position (19`) pivoted by means of a rocker 20 from its operating position (19) via a belt line 21', which is used to insert a beginning of the belt along the belt line 21 again shown in dashed lines. When the beginning of the strip is fixed on the second reel 16, the roller 19 pivots back into its operating position (19) shown in solid lines.

By adjusting the dancer rolls 12, 18, the tensile force within the metal strip 8 can thus be varied. An additional traction reinforcement results when at least one of the rollers 12, 13, 18, 19 is provided with braking means and/or drive means, not shown.

A hydraulic drive for the dancer roller 18 of the second roller arrangement 17 is shown schematically in the figure, the hydraulic drive having a double-acting hydraulic cylinder 22 . The dancer roller 18 is connected to a piston rod 23 that is adjustably arranged in a cylinder 24 of the hydraulic cylinder 22 and thereby adjustable in position. The hydraulic cylinder 22 is actuated via a hydraulic actuating arrangement 25 .

The dancer roller 12 of the first roller arrangement 11 is adjustable identically to the dancer roller 18 of the second roller arrangement 17 via a hydraulic cylinder and a hydraulic actuating arrangement, the hydraulic cylinder and the hydraulic actuating arrangement for the dancer roller 12 of the first roller arrangement 11 not being shown for the sake of clarity. In the following, therefore, the hydraulic actuation arrangement 25 for the second roller arrangement 17 is also described as representative of the hydraulic actuation arrangement of the first roller arrangement 11 .

In a roll cellar 26 below the level of the foundation 1 there is a hydraulic tank 27 in which hydraulic fluid is stored. Furthermore, a hydraulic pump 28 is arranged in the roll cellar 26 , which is fluidly connected to the hydraulic tank 27 via a hydraulic line 37 and delivers hydraulic fluid from the hydraulic tank 27 in the direction of the hydraulic cylinder 22 . In principle, several hydraulic pumps 28 can also be provided.

The hydraulic cylinder 22 is in turn connected to the hydraulic tank 27 in a fluid-conducting manner on the outlet side.

To control the hydraulic cylinder 22 , a controllable valve arrangement 29 is arranged between the hydraulic cylinder 22 and the hydraulic pump 28 , which is fluidly connected to the hydraulic pump 28 via an inlet line 38 and which has a hydraulic servo valve 30 . The valve arrangement is also connected to the hydraulic tank 27 by a return line 39 . The servo valve 30 can be controlled in such a way that the feed line 38 from the hydraulic pump 28 is blocked, just as the return line 39 from the hydraulic cylinder 22 to the hydraulic tank 27 can be blocked. Furthermore, the feed line 38 can optionally be fluidly connected to a first cylinder chamber 31 or a second cylinder chamber 32 of the hydraulic cylinder 22, with the return line 39 to the hydraulic tank 27 being connected to the other of the two cylinder chambers 32, 31. The piston rod 23 can thus be adjusted in the direction of the double arrow indicated. In order to enable the fastest possible adjustment of the hydraulic cylinder 22 and thus of the dancer roller 18, a hydraulic pressure accumulator 33 is arranged in the feed line 38 between the hydraulic pump 28 and the valve arrangement 29 in order to temporarily store hydraulic fluid previously delivered by the hydraulic pump 28 and, if necessary, to Hydraulic cylinder 22 to promote. The hydraulic pressure accumulator 33 is preferably arranged at a level of the foundation 1 or above and is also provided as close as possible to the hydraulic cylinder 22 in order to avoid line losses. In principle, it is also conceivable that several hydraulic pressure accumulators 33 are arranged in the feed line 38 .

A pulsation damper 34 is arranged in the return line 39 between the valve arrangement 29 and the hydraulic tank 27, it also being possible in principle for several pulsation dampers 34 to be provided. The pulsation dampener 34 serves to equalize the pressure fluctuations in the return line from the valve assembly 29 in order to counteract cavitation. In addition, a compensation tank 35 is provided between the pulsation damper 34 and the hydraulic tank 27, which ensures that hydraulic fluid can flow from the compensation tank 35 into the hydraulic tank 27 without pressure, so that no cavitation can occur in this area of the hydraulic line. The pulsation damper 34 is arranged as close as possible to the hydraulic cylinder 22 . In principle, however, it is also conceivable that no pulsation damper is provided in the return line 39 .

A force sensor in the form of a tension measuring cell 35 is provided between the hydraulic cylinder 22 and the coupling thereof to the dancer roller 18 . With this, the tensile and compressive forces that occur between the hydraulic cylinder 22 and the dancer roll 18 can be determined in order to be able to deduce the strip tension within the metal strip 8.

Furthermore, the hydraulic cylinder 22 has a pressure sensor 36 with which the hydraulic pressure within the second cylinder chamber 32 can be determined. The strip tension in the metal strip 8 can also be inferred from this determined pressure become. The pressure sensor can also be located in the first cylinder space 31 . Alternatively, several pressure sensors, for example one for the first cylinder chamber 31 and one for the second cylinder chamber 32 or for the hydraulic supply lines to the hydraulic cylinder 22 can be provided.

The hydraulic cylinder 22 is also equipped with an integrated distance measuring system 40, via which the position of the dancer roll 18 can be determined. Alternatively, the path measuring system 40 can be provided on another component that is moved with the dancer roller 18 . The position of the dancer roll 18 can be used to determine whether the dancer roll 18 is already in an end position of its adjustment path in order to be able to adjust the speed of the metal strip 8 if necessary. By changing the speed of the metal strip 8, for example by changing the reel speed, the position of the dancer roll 18 can be changed. If the reel speed of the second reel 16 is increased, more metal strip 8 tends to be diverted from the second roller arrangement 17 so that a shorter loop of metal strip 8 has to be stored in the second roller arrangement 17 in order to achieve a constant strip tension. In the embodiment shown, this is achieved by moving the dancer roll 18 to the left. So if the dancer roll 18 of the second roller arrangement 17 is in an end position in the illustration on the right, the speed of the second reel 16 must be increased in order to tend to move the dancer roll 18 back into a middle position. If the dancer roll 18 has reached a left end position, the speed of the second reel 16 must be reduced accordingly.

Reference List

1

foundation

2

mill stand

3

stripper

4

stripper

5

backup roll

6

backup roll

7

roll gap

8th

metal strap

9

first reel device

10

first reel

11

first roll arrangement

12

dancer role

13

role

14

swingarm

15

second reel device

16

second reel

17

second roller arrangement

18

dancer role

19

role

20

swingarm

21

tape line

22

hydraulic cylinder

23

piston rod

24

cylinder

25

actuation arrangement

26

roller cellar

27

hydraulic tank

28

hydraulic pump

29

valve assembly

30

servo valve

31

first cylinder space

32

second cylinder space

33

hydraulic accumulator

34

pulsation dampener

35

strain gauge

36

pressure sensor

37

hydraulic line

38

inlet line

39

return line

40

position measuring system

Claims (13)

1. An apparatus for controlling a strip tension in flexible rolling of metal strip, the apparatus comprising:

   a roller arrangement (11, 17) with at least one dancer roller (12, 18), the position of which is adjustable to control the strip tension of the metal strip (8),

   at least one hydraulic drive (22) coupled to the dancer roller (12, 18) for adjusting the latter,

   a hydraulic tank (27) for hydraulic fluid, which is fluidly connected to the hydraulic drive via a hydraulic supply line (38),

   a controllable valve arrangement (29) between the hydraulic tank (27) and the hydraulic drive (22) for controlling the hydraulic drive (22),

   a hydraulic pump (28) with which the hydraulic drive (22) is supplied with hydraulic fluid from the hydraulic tank (27), and

   at least one hydraulic pressure accumulator (33) for intermediate storage of hydraulic fluid previously delivered by the hydraulic pump (28), the hydraulic pressure accumulator (33) being arranged between the hydraulic pump (28) and the valve arrangement (29),

   characterized in that

   that a pressure sensor (36) for determining the hydraulic pressure is arranged in the hydraulic drive (22), wherein the apparatus is configured to infer from the hydraulic pressure to the strip tension of the metal strip (8) and to control the valve arrangement in dependence on the determined strip tension.
2. Apparatus according to claim 1,
   characterized in that
   that the hydraulic drive comprises a hydraulic cylinder (22).
3. Device according to claim 1 or 2,
   characterized in that
   in that at least one force sensor (35) is arranged on a roller (12, 13, 18, 19) of the roller arrangement (11, 17) for determining the forces acting on the roller (18) from the metal strip (8).
4. The device according to any one of claims 1 to 3,
   characterized in that
   in that a displacement measuring system (40) for determining the position of the dancer roller (12, 18) is arranged on the dancer roller (12, 18).
5. The device according to any one of claims 1 to 4,
   characterized in that

   that the hydraulic drive (22) is fluidly connected to the hydraulic tank (27) via a hydraulic return line (39), and

   in that a pulsation damper (34) is arranged in the return line (39).
6. Apparatus according to claim 5,
   characterized in that
   in that a surge tank (35) is arranged downstream of the pulsation damper (34).
7. The device according to any one of claims 1 to 6,
   characterized in that
   that the dancer roller (12, 18) is arranged horizontally adjustable.
8. The device according to any one of claims 1 to 7,
   characterized in that
   in that the roller arrangement (11, 17) has, in addition to the at least one dancer roller (12, 18), at least one further roller (13, 19), the at least one dancer roller (12, 18) and the at least one further roller (13, 19) being arranged vertically one above the other in such a way that the metal strip (8) is guided in the form of an S.
9. A rolling mill for flexibly rolling metal strip (8), the rolling mill comprising:

   a roll stand (2) with two work rolls (3, 4) between which a width-adjustable roll gap (7) is formed,

   a first strip guide unit with a first reel (10) for uncoiling metal strip (8),

   a second strip guide unit with a second coiler (16) for coiling rolled metal strip (8),

   characterized in that

   that in at least one of said strip guiding units a device according to one of claims 1 to 8 is arranged between the respective reel (10, 16) and the roll stand (2).
10. Method for regulating a strip tension during flexible rolling of metal strip (8) in a rolling plant with a device according to one of claims 1 to 8, wherein the valve arrangement (29) is controlled as a function of the strip tension of the metal strip (8) and, for the short-term provision of hydraulic fluid, the hydraulic drive (22) is at least partially fed with hydraulic fluid previously stored in the at least one hydraulic pressure accumulator (33),

    wherein the hydraulic pressure is measured at the hydraulic drive (22),

    wherein the hydraulic pressure is inferred from the strip tension in the metal strip (8), and

    wherein the valve arrangement (29) is controlled as a function of the determined belt tension.
11. The method of claim 10,
    characterized in that

    in that the forces acting from the metal strip (8) on a roller of the roller arrangement (11, 17) are measured,

    in that the strip tension in the metal strip (8) is inferred from the determined forces, and

    in that the valve arrangement (29) is controlled as a function of the determined belt tension.
12. A method according to claim 10 or 11 for controlling a rolling mill according to claim 9,
    characterized in that

    in that the position of the dancer roller (12, 18) of the at least one tape guide unit is determined by means of a displacement measuring system (40), and

    in that the speed of the reel (10, 16) of the at least one tape guide unit is controlled as a function of the position of the dancer roller (12, 18).
13. A method according to any one of claims 10 to 12 for controlling a rolling mill according to claim 9,
    characterized in that

    in that the roll gap setting of the roll stand (2) is determined, and

    in that the valve arrangement (29) is controlled in addition to the strip tension of the metal strip (8) as a function of the rolling gap (7).

Images