EP0154896B1 - Six-high mill - Google Patents

Description

The invention relates to a six-roll stand with backup roll drive, the backup rolls and the intermediate rolls and the work rolls being arranged essentially within a common vertical plane, with guide pieces for supporting roll bending and / or for balancing and / or for providing hydraulic cylinders provided in stand blocks and / or in the chocks and in the Stand windows arranged, causing a horizontal displacement of chocks of rollers horizontal adjustment device.

E.g. From "Production of Cold Rolled Strip, Part 1", Verlag Stahl Eisen mbH, Düsseldorf, 1970, pages 309/310, it is known to use work rolls of small diameter to create favorable deformation conditions. The reduction of the work roll diameter is, however, limited for several reasons. The deformation elements which can be transferred to work rolls of small diameter are limited by the cross-sectional area of the work roll journals; This problem of power transmission can, however, be countered by driving the work rolls by frictional engagement over the support and / or intermediate rolls. The horizontal deflection of the work rolls, which is unpleasantly noticeable in the case of slim work rolls, can also be reduced by, for example, using appropriate reel pulls or supporting work rolls horizontally.

Such support is not only achieved by separate support rollers arranged next to the work rolls; Such support can also be achieved relatively simply by pushing the work rolls out of the support roll plane in the rolling direction. Such a horizontal roller displacement is described, for example, in DE-A-33 35 857.5, and adjustment devices provided for this purpose can be found in DE-A-33 35 858.3.

In the case of axially displaceable work rolls and / or intermediate rolls, such as are required, for example, for the so-called "bottle rolling" according to DE-C-30 38 865, the drive of intermediate rolls proves to be unfavorable insofar as the drive elements, for example by means of Telescopic spindles, which had to compensate for the axial displacement of the intermediate rolls, while at the same time the power drives causing the displacement are to be accommodated in the same spatial area. According to a favorable solution, the backup rolls are therefore driven, which in turn operate the intermediate rolls by friction, which, in turn, take the work rolls with them through the friction effect. It is unfavorable that the circumferential forces acting on the intermediate rollers not only cause a high additional load on the bearings of the intermediate rollers, but also stress them on bending.

From FR-A-1 442 671 the horizontal displacement of work rolls on a four-high roll stand is known. However, this is a four-way reversing stand, in which, depending on the direction of rolling, the chocks of the work rolls are shifted with the help of horizontally arranged hydraulic cylinders so that the axes of rotation of the work rolls are on the left of the vertical plane spanned by the support roll axes and the other times to the right of it. The horizontal displacement of the roll chocks of the work rolls is accompanied by a vertical displacement of the backup rolls. The horizontal displacement of the work rolls proposed here is specifically geared to the four-high reversing stand.

From EP-A-0 059 417 a six-high roll stand with two work rolls, two intermediate rolls and two support rolls is known according to the preamble of claim 1, in which the intermediate rolls are arranged axially displaceably between the support rolls and the work rolls. In order to enable a wide range of strips to be rolled out with the six-high roll stand and for better strip edge rolling with constant operating conditions with as little pressure as possible between the work rolls and the intermediate rolls, bending devices for the intermediate rolls are provided in this known six-high stand, which are relative to the guide pieces and / or to the chocks of the intermediate rolls in the horizontal direction parallel to the roll axes but are displaceable in the axial direction. The measures proposed here for intermediate roll bending and for axial intermediate roll displacement can also be used in six-high rolling stands of the type in which the work rolls are shifted from the vertical axis plane of the intermediate rolls and the backup rolls and are supported in the direction of the shift. The six-high stand according to EP-A-0 059 417 shows a further design variant of a roller arrangement in which the axes of the work roller and intermediate roller lie in one axis plane, but this axis plane has been pivoted out of the vertical plane of the support rollers by a fixed angle cc. Accordingly, the chocks of the intermediate roller are fixed in the roller stand offset by a fixed constructive amount from the vertical plane. Extensive and controllable compensation of the mechanical stresses acting on the work rolls and the intermediate rolls and the circumferential forces acting on their bearings is not intended. Rather, the advantages of intermediate roll bending for optimal strip edge rolling of rolled strips of different widths are also to be used in this known six-high rolling stand.

The invention has for its object to provide a six-roll stand of the type described with a backup roll drive, in which the stress on the intermediate rolls rela tiv remains low ..

This object is achieved with the features of patent claim 1. With a relatively simple construction of work rolls stationary in the rolling direction, not only extensive and controllable compensation of the circumferential and supporting forces acting on the work rolls, as well as the differential forces resulting from the strip tension, is also achieved the circumferential forces acting on the intermediate rollers and their bearings are also compensated. Since in a six-roll stand both the rolling forces acting on the individual rolls and, in the case of the backup roll drive, whose circumferential forces are the same, but the compensation depends on angles, the compensation actually achieved also depends on the respective radii, so that the desired extensive compensation the forces loading the work rolls, if the compensation is brought about by moving out the intermediate rolls, also entail, if only partially, compensating for the forces acting on the intermediate rolls, which causes the desired relief.

It has proven useful here to design the horizontal adjusting devices as mechanical adjusting gears and to operate their drives mechanically or electrically in synchronism, so that synchronism of the horizontal adjustments is also necessarily achieved. On the other hand, the horizontal adjustment devices can also be designed as hydraulic cylinders which are operated in synchronism via control devices. Under certain conditions, however, it can prove advantageous to specify determinable deviations from the synchronism for the synchronizing devices. A relatively simple construction results if the horizontal adjustment devices each support wear plates or guide pieces for the blocks having the chocks of the intermediate rolls. Here, at least blocks provided one above the other can be connected to each other to form a frame by means of recesses in the beams reaching through or around beams, so that adjustment devices operated in synchronism also result in a vertical alignment of the wear plates.

In order to achieve further compensation of the forces acting on the intermediate rolls, the work rolls can preferably be arranged slightly offset with respect to the vertical having the plane of the support rolls, counter to the rolling direction. This results in an increase in the offset of the intermediate rollers compared to the plane having the backup rollers and thus the desired further compensation of the forces acting on the intermediate rollers when setting the desired offset between work and intermediate rollers. Appropriately, the cylinder blocks guiding the chocks of the work rolls have unequal strengths. On the other hand, the same and similar compensations can also be achieved in other ways: for example, both the intermediate and the work rolls could be displaceably displaceable by adjusting devices relative to the plane having the support rolls, as shown, the intermediate rolls can be displaced by adjusting devices while the work rolls are arranged offset by a predetermined mean dimension.

• Fig. 1 einen Vertikalschnitt durch ein Sechswalzengerüst,
• Fig. 2 schematisch die übliche stabilisierende Abstützung der Arbeitswalzen durch deren horizontale Versetzung in Walzrichtung,
• Fig. 3 eine gleichartige Darstellung mit horizontal verschobenen Zwischenwalzen,
• Fig. 4 schematisch entgegen der Walzrichtung versetzte Arbeits- und Zwischenwalzen, und
• Fig. 5 bis 10 Kräftepläne der im Falle von Anordnungen nach Fig. 2 bis 4 die Arbeitswalzen sowie die Zwischenwalzen beanspruchenden Kräfte.

The invention is explained on the basis of the following description of an exemplary embodiment in conjunction with the drawings which illustrate the same. It shows here.

• 1 is a vertical section through a six-roll stand,
• 2 schematically shows the usual stabilizing support of the work rolls by their horizontal displacement in the rolling direction,
• 3 is a similar representation with horizontally shifted intermediate rolls,
• Fig. 4 schematically offset from the rolling direction work and intermediate rolls, and
• Fig. 5 to 10 force plans of the forces in the case of arrangements according to Fig. 2 to 4, the work rolls and the intermediate rolls.

1 shows a section through a stand of a six-roll stand, in which stand legs 1 and 2, shown broken off, include parts of a stand window. Recesses 3 of the spars 1 and 2 accommodate horizontal adjustment devices 4 to 7, which can have screw spindles driven by worm drives. Blocks 8 are supported on the adjusting spindles of the horizontal adjusting devices, which have hydraulic cylinders having stamps 9 for balancing the chocks 10 of the support roller 11. Along the blocks 8 are vertically displaceable guide pieces 12, which support horizontally guided chocks 13 for intermediate rollers 14.

In the center of both flanks of the stand window support 15 are provided, which are equipped with the stroke of guide pieces 18 and 19, strips 16 and 17. In the guide pieces 18 and 19 guided vertically on the supports 15, chocks 20 and 21 of the upper and lower work rolls 22 and 23 are guided horizontally.

The horizontal variable support of the intermediate rolls 14 by means of the horizontal adjusting devices 4 to 7 makes it possible to set these intermediate rolls out of the common center plane of the stand, which has the axes of the support rolls and the work rolls. According to Fig. 1, the intermediate rollers are shown pushed to the right out of this central plane.

1 shows two variants in parallel: blocks 8 are shown on the left-hand side, which can be adjusted individually and independently of one another by horizontal adjustment devices 4 and 5, while blocks 25 are shown on the right-hand side are, which are connected by longitudinal bars 26 to form a frame, the longitudinal bars 26 being guided on both sides of the carrier 24 provided with recesses. When the adjustment devices 6 and 7 are operated in synchronism, strict compliance with the vertical is achieved by the blocks 25.

The hydraulic cylinders projecting up and down from the blocks 8 and 25 with their stamps 9 serve, as already mentioned, to balance the support rollers. The guide pieces 12 are each equipped with hydraulic cylinders 27 arranged one behind the other, which are double-acting, and whose free piston rod ends are fixed in the opposite guide piece 19, so that these hydraulic cylinders are able to transmit both positive and negative bending forces, axial displacements being caused by different loads on the Cylinders can be compensated. Accordingly, two successive hydraulic cylinders 28 are provided in the blocks 8, which cannot be recognized in the lower blocks by selecting a different cutting plane. The pistons of the hydraulic cylinders 28 are also designed to be acted upon on both sides, and the free ends of the piston rods are fixed in the guide pieces 12, so that both positive and negative bending forces can also be transmitted here. The other, smaller hydraulic cylinders shown serve to move to the starting positions for the roll change.

The displacements of work and / or intermediate rolls are explained schematically with reference to FIGS. 2 to 4. 2 shows six rolls of a six-roll stand one above the other, the work rolls being offset by an amount e in the rolling direction. The circumferential forces F _u resulting from the backup roller drive and the forces F _Hz and F _HA that stress the chocks of the intermediate rolls and the work _rolls are entered as well as the forces AF _r formed as a difference between the tensile forces occurring in front and behind the stand in the rolling stock, each half of the two work rolls is taken over. If one draws the force plan of the work roll according to FIG. 5 and the force plan of the intermediate roll according to FIG. 6, the same rolling forces F _w and the same peripheral forces F _u result for the rolls. In addition, each work roll is affected by half the amount of the respective strip tension difference AF _T , which can occur both in the positive and in the negative direction. According to FIG. 5, as already shown in FIG. 2, by displacing the work rolls by the distance e, both the circumferential force F _u which is stressing the work roll and the reaction force FK are inclined against the rolling force FW, so that the arrowhead of the reaction force F _K approaches the starting point of the rolling force and the resulting horizontal force F _HA is reduced compared to that which would result if the circumferential force Fu applied at right angles and accordingly also the reaction force F. Different degrees of compensation can be set by differently setting the offset e, but in any case the resulting horizontal force F _{H "is} considerably less than the actual circumferential force originally to be absorbed by the roll neck bearings. Depending on the dimensioning of the offset e, values of F _HA between 0 and 0.5 F _u and thus adjust the horizontal force acting on the work rolls as desired, however, there is only a very small compensation effect for the intermediate rolls according to Fig. 6, since only a part of the circumferential force F acting twice on the intermediate roll _u is compensated. Fig. 6 can recognize that one of the circumferential forces perpendicular attaches to the Walzkräft and only the second one is placed so inclined by the offset of the work roll that the force diagram tapers downwards, and a moderately reduced horizontal force F _Hz But with this the intermediate Rollers are subjected to a high degree of bending stress due to a high residual force, and the position of the intermediate rolls must also be designed in accordance with this high horizontal load. Since the rolling forces themselves are only transmitted via the intermediate rolls, they do not cause any stress.

According to the invention, an adjustment takes place, which is explained with reference to FIG. 3. Here the axes of the work rolls are held in the same plane in which the axes of the back-up rolls are located, and only the intermediate rolls are offset from the vertical plane by the dimension -e opposite to the rolling direction. Here, too, the goal is achieved of reducing the circumferential force exerted by the drive via the support rollers by the resulting horizontal rolling force component to such an extent that only a controllable residual component directed towards the intermediate roller remains and the work roller is relieved to such an extent that it can be relieved even at a low level Diameter proves to be stable and neither experiences significant deflection nor tends to vibrate. The respective degree of compensation can be set as desired using the horizontal adjusting devices 4 to 7 shown in FIG. 1. At the same time, however, there is also a corresponding shift by the same amount e with respect to the support rollers, so that, in accordance with the force plan of the intermediate roller shown in FIG. 8, the reaction force F _Kz between the intermediate roller and the support roller now experiences an inclination and due to this effect, additional horizontal displacement, the horizontal load on the intermediate roller is further reduced. However, a complete compensation of the horizontal forces is not possible without overcompensation of the work roll, because the sum of the radii of the support and intermediate rolls is larger than that of the work and intermediate rolls. The force plan of the work roll according to FIG. 7 corresponds to that of FIG Select the horizontal force F _{H "which} requires work rolls to be between 0 and 0.5 F _u , while with conventional radii the horizontal force of the intermediate rolls F _{Hz can be} between 0.5 F _u and 1 F _u .

This partial compensation of the intermediate roll according to FIG. 4 can be improved without significant effort, for example, in that the intermediate and the work rolls are additionally offset by the same amount against the rolling direction as shown in FIG. 3, so that the offset of the work roll is opposite the intermediate roll is maintained with e, while the offset of the intermediate roll with respect to the backup roll increases to the value g. As a result, the degree of compensation of the forces transmitted from the intermediate roll to the work roll is not changed, but rather the one for the forces transmitted from the backup roll to the intermediate roll is increased.

In practice, this effect can be easily used, for example, by displacing the work rolls by unevenly strong supports 15 and 24 by a basic amount against the rolling direction from the vertical of the support roll axes. As a result, without changing the transmission ratios between the work rolls and the intermediate rolls, an additional displacement of the intermediate rolls and thus a more extensive compensation of the peripheral forces is achieved, as the associated force map in FIG. 10 shows. The horizontal force F _Hz can be set between 0 and 0.5 F _u depending on the degree of compensation, so that both the bending stresses and the bearing loads on the intermediate rolls are further reduced considerably. In this case, a minimum or also an average value can be assumed for the additional fixed displacement, and the adjustment of the compensation of the forces acting on the more sensitive work roll can be effected by additional adjustment using the horizontal adjustment devices.

Finally, however, it is also possible to keep both the intermediate rolls and the work rolls displaceable as desired by means of horizontal adjustment devices, in order to be able to predefine any degrees of compensation both for the work rolls and for the intermediate rolls. In all these cases, not only is the load on the work rolls reduced, so that slimmer work rolls can be used without special support devices, but also the intermediate rolls are subjected to reduced bending forces and their bearing load is reduced accordingly.

Claims (8)

1. Six-high roll stand with backing roll drive, wherein the backing rolls (11) as well as the intermediate rolls (14) and the working rolls (22, 23) are arranged substantially within a common vertical plane, with guide members (12) supported in housing post blocks and/or in chocks (13) and/or with hydraulic cylinders (9, 27, 28) provided for balancing-out as well as with horizontal screw-down devices (4, 5, 6, 7), which are arranged in the housing windows and effect an horizontal displacement of chocks (13) of rolls (14), characterised thereby, that the horizontal screw-down devices (4 to 7) are associated with the chocks (13) of the intermediate rolls (14), that the horizontal screw-down devices (4 to 7) each support blocks (8) displaying plates subject to wear or guide members (12) for the chocks (13) of the intermediate rolls (14) and that the intermediate rolls (14) are resettable horizontally in or against the rolling direction out of the vertical plane common to the roll axes by the horizontal screw-down devices while maintaining their parallelism to the backing rolls.

2. Six-high roll stand according to claim 1, characterised thereby, that the horizontal screw-down devices (4 to 7) each support blocks (25) displaying plates subject to wear or guide members (12) for the chocks (13) of the intermediate rolls (14) and that at least blocks provided one above the other are connected together into a frame by longitudinal spars (26) engaging around guide carriers (15) or through passages of the guide carriers (24).

3. Six-high roll stand according to claim 1 or 2, characterised thereby, that the guide carriers (15, 24) for the guide members (18, 19) of the working roll chocks (20, 21) display unequal thicknesses.

4. Six-high roll stand according to at least one of the claims 1 to 3, characterised thereby, that the horizontal screw-down devices (4 to 7) are constructed as mechanical resetting gears and their drives are operated mechanically or electrically in synchronism.

5. Six-high roll stand according to at least one of the claims 1 to 3, characterised thereby, that the horizontal screw-down devices (4 to 7) are constructed as hydraulic cylinders and operated in synchronism by way of regulating devices.

6. Use of the six-high roll stand according to the claims 1 to 5, characterised by the measure that the intermediate rolls (14) are displaceable against the rolling direction and that the working rolls (22, 23) are arranged to be displaced slightly preferably against the rolling direction relative to the vertical displaying the axes of the backing rolls (11).

7. Use of the six-high roll stand according to the claims 1 to 5, characterised by the measure that the vertical plane drawn through the axes of the working rolls lies between the vertical plane of the axes of the intermediate rolls (14) and the vertical plane of the axes of the backing rolls (11).

8. Use of the six-high roll stand according to the claims 1 to 5, characterised by the measure that the intermediate rolls (14) and the working rolls (22, 23) are arranged to be displaced by the same amounts against the rolling direction.

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