EP0560192A1 - Rolling stand - Google Patents

Abstract

For rolling materials which are difficult to form to small end thicknesses, multi-roll stands with lateral guide arrangements for the work rolls are generally used. The required bending stiffness of the work rolls limits the minimum work roll diameter in four- or six-high rolling stands. In order to be able to achieve considerably smaller work roll diameters in such stands, it is proposed that the necks of the work rolls be supported without play in the radial direction. <IMAGE>

Description

The invention relates to a roll stand with two drag-driven work rolls, two back-up rolls and optionally two intermediate rolls for rolling flat material, preferably with small final thicknesses, the rolls being arranged in a vertical plane extending parallel to the back-up roll axes and being adjustably supported therein.

In such rolling stands, efforts are made to be able to roll difficult-to-form materials with small final thicknesses, to minimize the work roll diameter as much as possible. You quickly come up against limits given by the transferability of the necessary torque and the inherent rigidity of the work rolls. In order to be able to disregard the transferability of torques, the present invention already starts with drag-driven work rolls. The work roll diameter is therefore still dependent on the inherent rigidity of the work rolls, which can be determined as a function of the roll diameter, the rolling force and the length of the roll, as it results from the distance between the respective roll bearings.

By horizontally stabilizing the work rolls, their diameter can be reduced compared to that of conventional four or six roll stands, so that with certain roll lengths and occurring roll forces, corresponding minimum diameters are obtained of the work rolls. If the work roll diameter is to be reduced even further, this can only be made possible by side support concepts such as MKW, 12-roll or 20-roll stands.

Serious disadvantages of the lateral support concepts are that z. B. in cold rolling stands with such concepts can no longer be worked with emulsion. Thermal zone cooling is also not possible for scaffolds of this design due to space constraints. The corresponding stands can only be operated with rolling oil, which limits their operating speed, surface impurities, markings and tinsel are also the result. Further disadvantages can be seen in the high roller costs due to the high roller wear and the danger of the roller markings as well as the large lateral forces to be absorbed by the stand.

It is already known to support work rolls in the region of the bale near the pin by lateral support rollers or disks, whereby areas of the work roll bales are freely accessible, but the bending stiffness of work rolls supported in this way decreases drastically compared to 12- or 20-roll stands, so that the minimal possible work roll diameter must be increased significantly.

Furthermore, it is e.g. B. from DE-PS 34 31 691 known to provide two bearings in the axial direction one behind the other per trunnion. In the case of horizontal work roll bending devices thus formed, the dimensions of the bearings are selected such that, in comparison with stands without this bending device, slightly smaller work roll diameters can also be used here. The reason for this is that one of the two bearings seated on each roll neck is arranged very close to the roll bale, so that the bale length of the work rolls is approximately the same as that used to determine the bending stiffness Roller length corresponds. A bending in the bearings, with its adverse effects on the effective length to be taken into account for the bending stiffness, is attempted to counteract this by appropriate adjustment. However, little progress can be made with regard to the minimum work roll diameter.

The invention is therefore based on the object of designing a generic roll stand in such a way that it can be operated with work rolls whose diameter reaches the order of magnitude of the minimum diameter customary for MKW or 12-roll stands, but without the disadvantageous supports.

To achieve this object, it is proposed according to the invention that at least one bearing which is free of play or has little play in the radial direction is provided for each work roll.

This feature ensures that the horizontal deflection of the work roll is reduced by clamping the two roll ends without play or with little play. This means that, as is the case with conventional roller bearings, bending cannot already take place in the bearing. A possible bending line can only nestle tangentially to the roll neck axes. The reduced horizontal deflection means that rollers with smaller diameters can be used in order to obtain the same deflection under otherwise the same conditions as with conventional stands.

According to the features of claims 2 and 3, long bearing elements are proposed which enable the work rolls to be supported with little or no play in the radial direction, while several, possibly shorter bearing elements are arranged one behind the other in the axial direction of the roll journals.

It is also important that the support and / or intermediate rolls, but optionally also the work rolls, can be provided with axial displacement devices, bending means acting in the vertical direction and with ground crowning.

The storage of the work rolls according to the invention can be installed in short downtimes without great effort in conventional stands, so that these stands can be retrofitted with rigid work rolls of small diameter without problems and flat material with preferably small final thicknesses or difficult-to-form material grades can be rolled.

Figur 1

Die Biegelinie von Arbeitswalzen bei Gerüsten mit bekannter Lagerung,

Figur 2

die Biegelinie einer nach der vorliegenden Erfindung eingespannten Arbeitswalze,

Figur 3

eine schematisch dargestellte Teilseitenansicht eines Sechs-Walzengerüsts mit erfindungsgemäßer Arbeitswalzenlagerung und

Figur 4

eine schematische Darstellung der Draufsicht auf eine erfindungsgemäß gelagerte Arbeitswalze.

The invention is explained below with reference to a drawing. Show:

Figure 1

The bending line of work rolls on stands with known storage,

Figure 2

the bending line of a work roll clamped according to the present invention,

Figure 3

a schematically illustrated partial side view of a six-roll stand with work roll storage according to the invention and

Figure 4

is a schematic representation of the top view of a work roll mounted according to the invention.

A work roll 1 can be seen schematically as an axis in FIG. The work roll 1 is mounted in known bearings 2, 2 '. The bending stiffness of the work roll could be determined as a function of the length L _AS , the roll diameter and the rolling force F _WK . When the work roll 1 is loaded with The rolling force F _WK is caused by the horizontal component of a bending of the work roll, as shown at 1 '. It can be seen that the bend of the work roll 1 'extends from the center of the bearing 2 to the center of the bearing 2', the work roll 1 'thus also being bent in the storage area. This results in a relatively large deflection of the work roll 1 'in the area of the rolled strip 3.

In Figure 2, the same work roll 1 is shown, which is clamped in bearings 4 to 4 '''radially without play. With the same rolling force F _WK , the deflection of the work roll 1 'in the area of the rolled strip 3 is considerably smaller. The roller 1 'in the bearings 4 to 4''' does not bend. The roller 1 'nestles in the area of the bearings 4 to 4''' tangentially to the bending line of the unloaded work roller 1.

In order to obtain the same deflections as with the work roll 1 'according to FIG. 1 also in the case of the bearing according to FIG. 2, the work roll diameter could be reduced under otherwise identical conditions. The order of magnitude of the diameter reduction in a four- or six-roll stand with horizontal stabilization is approximately 40%, so that such stands, which have work roll bearings according to FIG. 2, can be operated with work rolls whose diameter has hitherto only been with 12-roll stands could be realized.

Figure 3 shows a six-roll stand with work rolls 1, 1a, intermediate rolls 5, 5a and backup rolls 6, 6a. The work rolls are vertically adjustably supported in the window of the roll stand, not shown, via pairs of shell-shaped slide bearings 4. For the intermediate rolls 5 and / or backup rolls 6 bending means, not shown, axial displacement means and ground crowns can be provided. As a rule, these corrective measures, which are brought about by the device for influencing the strip contour, are based on transfer the work rolls 4. If necessary, however, these means for influencing the bale contour on the work rolls 4 can also be provided. Thanks to the support systems that are not required, spray bars can be arranged in the work and intermediate roll level for process-optimized lubrication and cooling.

Figure 4 shows the top view of a work roll 1 with the associated play-free bearings 4 to 4 '''and 4₁ to 4₁'''. About the bearings 4, 4₁; 4 ', 4₁' and 4 '', 4 _{1 ''} , 4 '''4₁''' both sides of the work rolls 1 are clamped free of play, so that bending of the pins within the bearings is excluded. In addition, the bearings 4 ', 4₁'; 4 '', 4₁ '' are provided as close as possible in the area of the roll bale, so that the length L _AS, which determines the bending stiffness of the work rolls, is optimally minimized for a given bale length.

Claims (6)

Roll stand with two drag-driven work rolls, two support rolls and optionally two intermediate rolls, for rolling flat material with preferably small final thicknesses or material qualities that are difficult to form, the rolls being arranged essentially in a vertical plane extending parallel to the roll axes and being adjustably supported in this,
characterized,
that for each work roll (1, 1a) at least one bearing that is free of play or has little play in the radial direction is provided. Roll stand according to claim 1,
characterized,
that each bearing of the work rolls (1, 1a) is designed as a tensionable slide bearing with at least one continuous slot running in the axial direction. Roll stand according to claim 1,
characterized,
that each bearing of the work rolls (1, 1a) is composed of at least two support rollers which can be braced against the respective roll pin and which are arranged on the circumference of the roll pin in a radial plane, the support taking place essentially in the horizontal direction. Roll stand according to at least one of Claims 1 to 3,
characterized,
that each bearing of the work rolls (1, 1a) has a plurality of bearing elements (4, 4 ', 4'',4'''; 4₁, 4₁ ', 4₁'',4₁''') arranged one behind the other in the axial direction. Roll stand according to at least one of Claims 1 to 4,
characterized,
that at least one pair of rollers, as is known per se, is assigned bending means and / or means for axial displacement, it being possible for at least one pair of rollers, as is also known, to have a ground crown. Roll stand according to at least one of Claims 1 to 5,
characterized,
that at least one pair of rollers, as is known per se, projects horizontally for horizontal stabilization from the vertical plane formed by the roller axes.

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