EP0587995B1 - Set of rollers with at least two deflection rollers for S-shaped deflection of thin metal strips - Google Patents

Description

The invention relates to a roller set with at least two deflecting rollers for the S-shaped deflection of thin metal strips, in particular metal strips with a strip thickness of up to 1 mm, at least one of the two deflecting rollers having a roller shell which can be adjusted between a convex outer curvature and a concave inner curvature, and the respective Metal strip is guided around the adjustable deflecting roller with a predetermined wrap angle, the deflecting roller with the adjustable roller shell also having a pressure chamber arranged between the roller shell and the roller core and having a pressure medium supply for a hydraulic or pneumatic pressure medium.

Straightening processes such as tension stretching and stretch bending straightening are known for leveling metal strips. Although these straightening processes are relatively advanced, light center bowls or edge shafts sometimes have to be accepted after leveling. These residual unevenness results from transverse stresses distributed unevenly over the bandwidth, which are superimposed on the tensile stresses in the longitudinal direction of the strip. The smaller the strip thickness and the modulus of elasticity of the metal strip in question, the greater the risk of residual unevenness.

The same applies to cold rolling, in particular for post-rolling or skin pass rolling. Due to a deflection of the rollers due to the rolling force and because the input thickness profile of the metal strips is not regularly rectangular, there are uneven deformations in the Roll gap across the strip and thus to ripples after cold rolling. Correction of the roll gap geometry is often attempted, but the mentioned ripples cannot be avoided on a regular basis. In fact, the deformation in the roll gap depends not only on the distribution of the rolling force, but also on the tension distribution over the strip width.

A roller set of the embodiment described at the outset is known, which is used for deflecting metal strip during rolling and has deflection rollers which are acted upon by pressure medium and have an adjustable roller shell. In this case, a convex outer curvature of the respective roll shell is achieved by a corresponding oil pressure in a pressure chamber. In addition, an internal curvature should occur when the internal pressure is reduced. In this respect, however, it can hardly be a concave inner curvature, since the roller jacket inevitably adapts to the contour of the pressure chamber at least in regions when the pressure chamber is relieved. In addition, a bending device is provided for the deflection rollers, which is used to produce a convex or concave deflection of the entire deflection roller and consequently its roller jacket (cf. JP-A-53 117 665, Patents Abstracts of Japan).

In the case of a similar set of rollers with crowning supported by pressure medium, the deflection rollers do not serve for the S-shaped deflection of metal strips, but for adjusting the tension distribution over the strip width in order to obtain a strip thickness that is as uniform as possible and planed metal strips (cf. JP-A-53 117 664, Patents Abstracts of Japan).

The invention has for its object to provide a roller set of the embodiment described above, with which in the course of leveling metal strips edge shafts or center bowls can be significantly reduced or eliminated entirely.

This object is achieved by the invention in the case of a generic roller set in that the concave inner curvature is formed by negative pre-grinding in the depressurized state. - These measures of the invention have the result that with a continuous metal strip and convex outer curvature, a tensile concentration is established in the edge zones on at least one of the two deflection rollers. The tensile stress concentrations result in locally higher plastic deformations. Edge waves or center dishes that exist in the metal strip in question due to differences in length of individual metal strip strips over the strip width can thus be reduced or eliminated entirely. Because with a convex outer curvature of the guide roller, the middle of the belt is overstretched and edge waves are eliminated in this way, while with a concave inner curvature of the guide roller, the transverse stresses that otherwise build up from the belt edges towards the center of the belt, i.e. the belt center area is now lengthened like the belt areas, so that center bowls no longer occur. Higher tensile stresses can always be built up in the central area or edge areas of the respective metal strip and the tensile stresses required for leveling can be applied to the strip edge areas as well as the strip center area. In fact, with a suitable choice of the inner contour of the roller shell, a parabolic outer curvature of the roller shell is achieved. Due to the negative pre-grinding on the other hand, a parabolic internal curvature can be achieved, so that the crowning of the deflecting rollers or their roller jacket in question can be adjusted positively or negatively within predetermined limits.

According to one embodiment of the invention, which is of independent importance, it is provided that the two deflection rollers are designed as a tension roller set - with a driven pull roller and brake roller - and between the two deflection rollers a tensile stretch is built in order to level metal strips which are particularly sensitive to surface, for example for lithographic Purposes. The aim here is to avoid stretch-bending straightening to level the metal strips in order to avoid surface damage. According to another embodiment of the invention with independent importance, it is provided that four deflecting rollers form two sets of tensioning rollers and a cold rolling mill and / or a stretch-bending leveling mill is arranged between the two tensioning rollers and braking rollers, with at least the one that is immediately upstream and immediately downstream of the cold rolling mill or stretch-bending leveling tower Deflection roller has a convex to concave adjustable roller jacket. In these cases, similar effects are achieved in cold rolling and stretch bending straightening as in tensile stretching. By means of targeted tensile stress concentrations either in the strip center area or in the strip edge areas, greater degrees of stretching are achieved not only for tensile stretching, but also during stretch bending straightening and a greater reduction in thickness during cold rolling, in order to eliminate edge shafts or center dishes, as a result of a higher plastic deformation. All deflection rollers or roller pairs can always be convex to have concave adjustable roller jacket to enhance the effects described. The deflecting rollers are arranged, for example, in pairs, one above the other, in the interposition of a cold rolling stand, and horizontally next to one another in the interposition of a stretch-bending straightening stand. In order to achieve particularly pronounced higher plastic deformations in the belt center area or in the belt edge areas, the roller diameter of the adjustable deflection rollers is at least 250 mm, while the wrap angle is at least 90 ° and preferably greater than 150 °.

In addition, the pressure medium supply can have an axial rotary feedthrough in one of the two bearing journals of the respective deflection roller and the pressure chamber can have a vent hole. The vent hole is required to fill the pressure chamber with the pressure medium for the first time.

Fig. 1

einen erfindungsgemäßen Rollensatz in der Ausführungsform eines Spannrollensatzes mit zwischen den beiden Umlenkrollen gebildeter Zugreckstrecke,

Fig. 2

zwei erfindungsgemäße Rollensätze in der Ausführungsform von Spannrollensätzen mit einem zwischengeschalteten Kaltwalzgerüst,

Fig. 3

zwei erfindungsgemäße Rollensätze in der Ausführungsform von Spannrollensätzen mit einem zwischengeschaltetem Streckbiegerichtgerüst,

Fig. 4

eine einstellbare Umlenkrolle nach der Erfindung im Axialschnitt und

Fig. 5

ausschnittsweise den Gegenstand nach Fig. 1 mit konvexer Außenwölbung nach a), konkaver Innenwölbung nach b) und dem möglichen Arbeitsbereich durch die Kombination von a) und b).

In the following, the invention is explained in more detail with reference to a drawing showing only one embodiment; show it:

Fig. 1

1 a roller set according to the invention in the embodiment of a tension roller set with a stretching section formed between the two deflection rollers,

Fig. 2

two roller sets according to the invention in the embodiment of tension roller sets with an interposed cold rolling mill,

Fig. 3

two roller sets according to the invention in the embodiment of tension roller sets with an intermediate stretch-bending straightening frame,

Fig. 4

an adjustable pulley according to the invention in axial section and

Fig. 5

1 with the convex outer curvature according to a), concave inner curvature according to b) and the possible work area by the combination of a) and b).

The figures show a set of rollers with at least two deflection rollers 1, 2 for the S-shaped deflection of thin metal strips 3, in particular of metal strips with a strip thickness of up to 1 mm and a strip width of more than 800 mm. At least one of the two deflection rollers 1 or 2 has a roller jacket 6 that can be adjusted between a convex outer curvature 4 and a concave inner curvature 5, the respective one Metal strip 3 is guided around the adjustable deflection roller with a wrap angle of at least 90 °, preferably more than 150 °.

1, the two deflection rollers 1, 2 can be designed as a tension roller set with a driven pull roller 1 and brake roller 2. In this case, a tensile stretch Z is set up between the two deflection rollers 1, 2.

According to FIGS. 2 and 3, four deflecting rollers 1, 2, 7, 8 form two sets of tensioning rollers, a cold-rolling stand 9 or a straightening-bending stand 10 being arranged between the two tensioning roller sets 1, 7 and 2, 8 forming brake rollers. At least the deflecting roller 1, 2 which is immediately upstream and immediately downstream of the cold rolling stand 9 or the stretch-bending stand 10 has a roller jacket 6 which is adjustable from convex to concave.

All deflecting rollers 1, 2, 7, 8 or pairs of rollers can always have a roller jacket 6 which can be adjusted from convex to concave. 2, the deflection rollers 1, 7 and 2, 8 are arranged vertically one above the other in pairs, according to FIG. 3 arranged horizontally next to one another. The roller diameters 1, 2 and 7, 8 of the adjustable deflection rollers are at least 250 mm, so that, taking into account a wrap angle of more than 90 ° and in particular more than 150 °, sufficiently high plastic deformations can be achieved in either the belt edge area or the belt center area.

In Fig. 4, a deflection roller 1 is shown with a convex to concave adjustable roller shell 6, which has a pressure chamber 12 with a pressure medium supply 13 for a hydraulic or pneumatic pressure medium between the roller shell 6 and the roller core 11, the concave inner curvature 5 when depressurized is formed by a negative pre-grinding. The pressure medium supply 13 has an axial rotary feedthrough 14 in one of the two bearing journals 15 of the respective deflection roller 1 and the pressure chamber 12 has a ventilation hole 16 for the initial filling.

Claims (8)

1. A set of rollers with at least two deflection rollers (1,2) for the S-shaped deflection of thin metal strips (3), in particular of metal strips (3) with a strip thickness of up to 1 mm, in which at least one of the two deflection rollers (1,2) has a roller casing (6) which is adjustable between a convex outer curvature (4) and a concave inner curvature (5), and the respective metal strip (3) is guided around the adjustable deflection roller (1, 2) with a given winding angle, in which in addition the deflection roller (1) with the adjustable roller casing (6) has a pressure chamber (12) arranged between the roller casing (6) and the roller core (11) with a pressure medium inlet (13) for a hydraulic or pneumatic pressure medium, characterised in that the concave inner curvature (5) in pressureless state is formed by a negative rough grinding.
2. A set of rollers according to Claim 1, characterised in that the two deflection rollers (1, 2) are constructed as a set of tension rollers and between the two deflection rollers a tension strain section (Z) is set up.
3. A set of rollers according to Claim 1, characterised in that four deflection rollers (1,2, 7, 8) form two sets of tension rollers and between the two sets of tension rollers (1, 7 and 2, 8) a cold rolling stand (9) and/or a stretch-bending-straightening stand (10) is arranged, in which at least the deflection roller (1, 2) arranged immediately before and immediately after the cold rolling stand (9) or stretch-bending-straightening stand (10) has a roller casing (6) which is able to be adjusted from convex to concave.
4. A set of rollers according to one of Claims 1 to 3, characterised in that always all the deflection rollers (1, 2, 7, 8) or pairs of rollers have a roller casing (6) which is able to be adjusted from convex to concave.
5. A set of rollers according to one of Claims 1 to 4, characterised in that the deflection rollers (1, 7 and 2, 8) are arranged in pairs vertically one above the other or horizontally adjacent to each other.
6. A set of rollers according to one of Claims 1 to 5, characterised in that the roller diameter of the adjustable deflection rollers (1, 2, 7, 8) amounts to at least 250 mm.
7. A set of rollers according to one of Claims 1 to 6, characterised in that the angle of bending around is at least 90° and is preferably greater than 150°.
8. A set of rollers according to one of Claims 1 to 7, characterised in that the pressure medium inlet (13) has an axial rotary duct (14) in one of the two journals (15) of the respective deflection roller (1) and the pressure chamber (12) has a ventilation bore (16).

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