GB2211451A

GB2211451A - Multi-roll rolling mill

Info

Publication number: GB2211451A
Application number: GB8825018A
Authority: GB
Inventors: Jurgen Sondermann
Original assignee: Josef Frohling GmbH
Current assignee: Josef Frohling GmbH
Priority date: 1987-10-29
Filing date: 1988-10-26
Publication date: 1989-07-05
Anticipated expiration: 2008-10-26
Also published as: DE3736683C2; GB2211451B; FR2622484B1; DE3736683A1; DE3736683C3; GB8825018D0; FR2622484A1

Description

2211451 A MULTI-ROLL ROLLING MILL This invention relates to a multi-roll

rolling mill for cold rolling strip material, such as metal strips. Rolling mills are known for this purpose, which have working rolls, back-up rolls disposed on a common axle which are advanced or withdrawn by bracing components, and with intermediate rolls optionally disposed between the working rolls and the back-up rolls.

Where such known multi-roll rolling mills are concerned, a number of back-up rolls are mounted on a continuous axle or shaft. Disposed between the individual back-up rolls are bracing components via which force is transmitted to a rolling mill. The outer bracing components, i.e. those disposed at the ends of the continuous axle or shaft, are fixedly mounted, while the middle or inner bracing components can be individually advanced.

This capacity to advance the inner bracing components makes it possible to flex the continuous back-up roll axle so that the overall elasticity of the 1-5 rolling mill can be compensated for or the elasticity of the stand may be influenced on a spot-wise basis via the working rolls (and possibly via intermediate rolls disposed between the working rolls and back-up rolls).

Thus it is possible, for example in the case of a rolled strip which has a central undulation (caused by the strip centre being too long), to produce flatness 1 n the strip by reducing the rate of advance of the middle bracing components, whereas in the case of a rolled strip which has a marginal undulation (caused by the fact that the strip sides are too long), the rate of feed or advance of the middle bracing components is increased in order to achieve flatness in the rolled strip.

1 There are however limits to the extent by which the flatness of the rolled strip can be influenced by controlled advance of the middle bracing components or the middle back-up rolls, limits which are imposed by the inherent rigidity of the working rolls and of any intermediate rolls which may be provided. This can mean that under an intense advancing force of the middle bracing components, the working rolls or intermediate rolls no longer have their full length bearing reliably on the outer back-up rolls. The result is an unstable condition which makes it impossible to influence strip feed. Such as unstable condition is mainly countered by reducing the rolling 2 force or the reduction in thickness of the strip at each pass to a minimum, or by rolling strips the width of which is substantially less than that for which the relevant rolling mill is intended.

Since furthermore during rolling there is no infinite adjustment of the middle or inner bracing components, a finite adjustment must necessarily result in a sudden change in the flatness of the rolled material. Finally, an adjustment of the central bracing components can also produce an undesired change in the height of the roll gap.

Thus there is a need for a generally improved multi-roll rolling mill which minimises the aforesaid difficulties.

According to the present invention there is provided a multi-roll is rolling mill for cold rolling strip material, which mill has at least one working roll, a plurality of sets of back-up rolls, with each set of backup rolls being disposed on its own common axle, and bracing components operable to advance or withdraw the back-up rolls, whereirf the bracing components for the axle of each set of back-up rolls are movable to advance the back-up rolls in an infinitely variable manner, and wherein force transmitting elements are provided which engage, with an infinitely variable force, the ends of each back-up roll set axle and which are operable to advance the outer back-up rolls of the associated set.

This presupposes that with the infinitely adjustable force engaging both ends of the back-up roll axle (preferably by means of piston and cylinder assemblies), the elastic deformation of the component elements caused by the rolling force of mainly the middle or inner back-up rolls also extends to the outer back-up rolls, -so that the working rolls or any intermediate rolls which may be provided bear over their entire length on the outer back-up rolls whereby the working rolls are maintained parallel to on another. Since all the bracing components are infinitely advanceable (preferably by means of wedges and spindles), the adjusted line of flexion of the back-up roll axle can also be altered during rolling without such a change causing a sudden variation in the flatness of the stock being rolled.

Finally, a rolling mill of the invention ensures that when rolling strips the width of which is less than that for which the rolling the rolling mill is actually envisaged, the rolling pressure of the working rolls at the edge of the strip or laterally alongside the strip can be reduced so that even very narrow strips can be rolled with optimum results.

Preferably the lateral ends of any intermediate rolls which are provided are engaged by a force which applies the total length of the intermediate rolls against the advanced back-up rolls. Furthermore, the lateral ends of the working rolls may be engaged by a further force which causes the total length of the working rolls (possible via existing intermediate rolls) to be applied against the advanced back-up rolls.

For a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made, by way of is example, to the accompanying drawings, in which:

Figure 1 is a partially sectioned side view of an upper part of a first embodiment of a multi-roll rolling mill according to the invention, with intermediate rolls, Figure 2 is a cross-sectional view from one end of the upper part of Figure 1, Figure 3 is a partially sectioned side view of an.upper part of a multi roll rolling mill according to a second embodiment of the invention, and Figure 4 shows diagrarnatically from one end of Figure 3 a crosssection through the upper part of Figure 3.

Figures 1 and 2 show an upper part 1 of a 12-roll multi-roll rolling mill according to a first embodiment of the invention with the disposition of three s ets of back-up rolls 2, back-up rail axles 3 and bracing components 4 disposed between the back-up rolls 2. A working roll 5 is braced or loaded via intermediate rolls 6 and the back-up rolls 2. Each set of back-up rolls 2 is mounted on its own continuous back-up roll axle 3 and the axle 3 is in turn supported in the upper part or housing 1 via the bracing components 4.

4 These bracing components 4 in the more central portion of the axle 3 are, according to the invention, connected to an advancing device which operates on an infinitely variable basis. It consists, for example, of wedges 3, 31 which cooperate with a spindle 8 (Figure 1), but also other alternative infinitely variable operating feed means can be used.

The rolling force produces an elastic deformation of the working rolls 5, the intermediate rolls 6, the back-up rolls 2, the back-up roll axle 3 and also of the bracing components 4, mainly in the more central portion of the axle 3 which corresponds to the strip width to be rolled. The components disposed laterally thereof, namely the outer back-up r olls, and the components 41 are less heavily loaded and are therefore less elastically def ormed.

In order, then, despite this varying loading or elestic deformation, to keep the roll gap parallel, the invention envisages providing at the outer ends 31 of the back-up roll axle 3, force transmitting elements which produce a loading also on these laterally disposed outer component elements so that the elastic deformation in the outer zones is of the same magnitude as the elastic deformation in the middle zone.

The infinitely variable force-transmitting elements which may be used are preferably piston and cylinder assemblies but other infinitely variable force-transmitting elements may be employed. Preferably, the force-transmitting elements are hydraulic cylinders 9 connected to the rolling mill stand 1 and connected, via articulations or pivots 11, to axle bearings 10 for the outer ends 3' of the back-up roll axles 3.

The infinitely adjustable preliminary setting of a line of flexion of the back-up roll axle 3 now takes place by means of the wedge-axle arrangement 7, 711 8 jointly with the cyinder arrangement 9, 11, 10, until a roll gap profile is achieved which is desired to suit the intended rolling process. The infinite adjustabill ty also makes it possible even during the rolling process to make a change in the setting without any sudden change in the flatness of the stock being rolled.

In order to improve application of the working rolls and of any intermediate rolls which may be provided against the outer back-up rolls, preferably further force-transmitting elements are provided, to engage, with infinitely adjustable force, outer journals 51 of the working roll 5 andlor outer journals 6' of any existing rolls 6.

Figures 3 and 4 show an alternative embodiment of the invention in which at the two outer journals 6' of the intermediate rolls 6, journal bearings 13 engaged, through an articulation or pivot 14, by a preferably hydraulic operated piston and cylinder assembly 12 which is connected to the rolling mill stand. The cylinder assemblies 12 apply the intermediate rolls 6 rigidly.against the back-up rolls 2, as is shown in exaggerated fashion in Figure 4.

By virtue of the infinitely regulatable traction force of the cylinder assemblies 12 engaging the ends 61 of the intermediate rolls 6, elastic deformations occuring in the components of the rolling mill during rolling are jointly determined by flexion of the intermediate rolls 6.

The flexing arrangement for the back-up roll axle 3 according to Figures 1 and 2, comprising piston and cylinder 9, spindle bearings 10 and articulation 11, is in construction similar to the flexing arrangement for the intermediate rolls 6 according to Figure 3, comprising piston and cylinder assemblies 12, journal bearings 13 and articulation 14. This back-up roll flexing arrangement 9, 10, 11 can be provided or actuated by itself or jointly with the intermediate roll flexing arrangement 12, 13, 14.

1 Finally, extended journals 51 of the working rolls 5 can be engaged by (not shown) flexing means which are similar to the flexing arrangements 9, 10, 11 or 12, 13, 14 and which serve to improve application of the working rolls against the outer back-up rolls or intermediate rolls.

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Claims

1. A multi-roll rolling mill for cold rolling strip material, which mill has at least one working roll, a plurality of sets of back-up rolls, with each set of back-up rolls being disposed on its own common axle, and bracing components operable to advance or withdraw the back-up 5 rolls, wherein the bracing components for the axle of each set of back-up rolls are movable to advance the back-up rolls in an infinitly variable manner, and wherein force-transmitting elements are provided which engage, with an infinitely variable force, the ends of each back-up roll set axle and which are operable to advance the 10 outer back-up rolls of the associated set.

2. A rolling mill according to Claim 1, including wedges cooperating with a spindle, for infinitely variable advance of the bracing components. 15

3. A rolling mill according to Claim 1 or Claim 2, wherein the forcetransmitting elements are piston-cylinder assemblies.

4. A rolling mill according to Claim 1, wherein the force- transm i tting 20 elements are hydraulic cylinders which are connected to a stand of the mill and which are connected, through articulations, to bearings for the outer ends of the back-up roll axles.

5. A rolling mill according ko any one of Claims 1 to 4, including 25 intermediate rolls.

6. A rolling mill according to Claim 5, wherein the intermediate rolls are located between at least one working roll and the associated sets of back-up rolls. 30

7. A rolling mill according to any on of Claims 1 to 6, including further force-transmitting elements which engage, with infinitely adjustable forces, outer journals of the at least one working roll and/or outer journals of the intermediate rolls, when the latter'are present.

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8. A rolling mill according to Claim 7, wherein the further forcetransmitting elements for the intermediate rolls are hydraulic cylinders and journal bearings which are connected to one another via articulations. 5

9. A rolling mill according to Claim 7 or Claim 8, wherein the forcetransmitting elements for the at least one working rail are hydraulic cylinders and journal bearings which are connected to one another via articulations. 10

10. A multi-rall rolling mill for cold rolling strip material, substantially as hereinbefore described with reference to Figures 1 and 2 or Figure 3 and 4 of the accompanying drawings.

is Ir Published 1989 at The Patent 0Ince, State House, 66171 High Holborn, London W. C1R 4TP. Further copies maybe obtained from The Patent Oflice. Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent, Con. 1187