Guiding device for chocks of work rolls in roll stands

Abstract

The invention relates to a device (2) for guiding chocks (12) arranged to support two work rolls (10) forming a roll gap of a roll stand (1) and a roll stand. The device (2) comprises two bending blocks (20) for accommodating one chock (12) each, at least one guide (15) for guiding the bending blocks (20) such that the bending blocks (20) are movable relative to one another along the guide (15), and a number of bending actuators (30) arranged to move the bending blocks (20) relative to one another along the guide (15).

Description

[Technical field]

[0001] The invention relates to a device for guiding chocks designed to support work rolls which form the roll gap of a roll stand and to a roll stand for rolling strip-shaped rolled products, preferably for rolling cold strip in a cold rolling plant. [Background technology]

[0002] In the case of flat-rolled metal products, the slab or strip passes through one or more roll stands, which comprise at least two parallel-oriented work rolls that form a roll gap through which the strip passes for thickness reduction. In addition to the work rolls, roll stands usually also comprise backup rolls and / or intermediate rolls, which cooperate with the work rolls for various reasons, e.g. stabilization of the work rolls, power transmission, etc.

[0003] The work rolls can distort under load, so that the rolled metal strip does not have a constant thickness across the strip width. Various measures are known to improve the flatness of the rolled product or generally to affect its cross section, such as crowning, axial shifting or bending of the work rolls by forces acting on the roll neck.

[0004] Systems for bending work rolls are described, for example, in DE 3906618 A1 and WO 2008 / 080476 A1. They are formed of a cassette structure with bending blocks guided on rods which hold and guide chocks for supporting the work rolls. To bend the work rolls, the latter are usually tensioned against the respective backup rolls via piston / cylinder units, so that the latter, in cooperation with a suitable backup roll profile, receive the desired positive bending, i.e. a bending convex with respect to the rolling surface of the rolled product.

[0005] However, in special cases, a negative bending of the work rolls, i.e. a concave bending with respect to the rolling surface of the rolled product, is desired, for example in skin pass rolling at low rolling forces. However, such a negative bending concept is not possible in previous installations of cassette construction or is limited to very low negative bending forces. This applies in particular to installations with small roll diameters.

[0006] EP 0 623 401 A describes a bending block for bending rolls of a multi-roll roll stand, in which pairs of partial bending jaws are guided vertically one above the other. DE 10 2007 001 322 A1 describes a guide device for chocks of work rolls. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] German Patent No. 3906618 [Patent Document 2] International Publication No. 2008 / 080476 [Patent Document 3] European Patent Application Publication No. 0623401 [Patent Document 4] DE 102007001322 Summary of the Invention [Problem to be solved by the invention]

[0008] The object of the present invention is to provide an improved device for guiding chocks which are designed to support the work rolls which form the roll gap of a roll stand, as well as an improved roll stand for rolling strip-shaped rolled products, in particular to expand the range of application of the roll stand. [Means for solving the problem]

[0009] The problem is solved by a device having the features of claim 1 and 6 The problem is solved by a roll stand having the features of: Advantageous developments can be seen from the dependent claims, the following description of the invention and the description of preferred embodiments.

[0010] The device according to the invention, also referred to here as "guide device", is used to guide chocks for work rolls in a roll stand which is designed for rolling a strip-shaped rolled product, preferably for rolling cold strip in a cold rolling plant. The rolled product is preferably a steel sheet, but other metals and alloys, such as, for example, aluminum, copper and magnesium, are also conceivable.

[0011] The apparatus includes two bending blocks each for receiving one of the chocks and at least one guide for guiding the bending blocks such that the bending blocks are movable relative to one another along the guides. The apparatus further includes a plurality of bending actuators configured to move the bending blocks relative to one another along the guides.

[0012] In other words, the bending actuator is arranged to apply a bending force to the work rolls while being mounted between both bending blocks. This can be a positive bending force, in which case the bending blocks are moved apart along the guide, so that the work rolls, in cooperation with the backup rolls, tend to bend convexly with respect to the rolling surface of the rolled product. Alternatively, a negative bending force can be achieved, which moves the bending blocks towards each other. Rolling under a negative bending force can be performed, for example in skin pass mode, by lifting the upper backup roll, i.e. with only a negative bending force as rolling load.

[0013] A guide device with multiple bending actuators allows rolling with relatively high negative bending forces for special rolling operations. Furthermore, normal rolling applications can be carried out with positive and low negative bending forces, whereby the range of application of a roll stand with one or more guide devices is expanded with only minor additional constructional efforts, i.e. without special adjustment cylinders or similar systems. In addition, the bending system is particularly low-friction.

[0014] According to the present invention,Just three bending actuators are provided per guide device, so that the range of application can be maximized with only minor structural modifications and while maintaining conventional devices.

[0015] song The bending actuators are each configured as a piston / cylinder unit with a bending cylinder and a bending piston supported and movable in the bending cylinder, the bending cylinder being arranged or introduced in one of the two bending blocks, while the corresponding bending piston is fixed in the other bending block via a bending piston rod. The actuation of the piston / cylinder units is preferably performed hydraulically. The application of such an installed piston / cylinder unit allows for a cassette construction, in which the bending actuator acts perpendicularly on the positively guided bending blocks, which in turn accommodate chocks. The cassette construction allows for a space-saving and flexible modular construction.

[0016] According to the present invention, The three piston / cylinder units are arranged in the axial direction of the work roll with two outer piston / cylinder units and one central piston / cylinder unit. The central piston / cylinder unit is 、 The outer piston-cylinder unit is installed inversely, which allows for an increased cooling effect when applying bending forces and furthermore allows for a particularly space-saving installation of the piston-cylinder unit.

[0017] The piston / cylinder units can be used together or alternatively, and in particular in the case of three piston / cylinder units, only the outer piston / cylinder unit or only the inner piston / cylinder unit can be used.

[0018] The piston ring side of the piston / cylinder units can also be used for power transmission. This means, for example, that in the case of three piston / cylinder units, negative bending forces are available from the piston face of the central piston / cylinder unit and the piston ring faces of the outer piston / cylinder units, or only from the piston face of the central piston / cylinder unit. The opposite is true for positive bending.

[0019] Preferably, the two bending blocks are arranged vertically in their mounting position, i.e. in the direction of gravity, one above the other, so that an upper bending block and a lower bending block are defined, which in the mounted state are thus correspondingly assigned to the upper and lower work rolls. The bending cylinders of the outer piston / cylinder units are preferably arranged in the lower bending block, whereas the bending cylinders of the central piston / cylinder unit are arranged in the upper bending block.

[0020] It should be noted that spatial relationship terms such as "above", "below", "up and down", "above", "below", "horizontal", "vertical", etc. are uniquely defined by the intended mounting position of the guide device within the roll stand.

[0021] Preferably, the bending blocks each comprise at least one guide bush which is in sliding contact with a guide, so that a reliable guiding of the bending blocks is achieved with a constructionally simple construction.

[0022] Preferably, the guide or guides are formed as circular guides, i.e. as rod-like or cylindrical bodies. The application of circular guides provides that there is a clear guide relationship, that problem-free lubrication is guaranteed, and that only little mechanical engineering effort is required to seal the guide device, without the risk of oversetting that occurs with nested flat guides. Circular guides can be manufactured inexpensively with little design effort and are easy to assemble and maintain.

[0023] The problem is further solved by a roll stand for rolling a strip-shaped rolled product, preferably for rolling cold strip in a cold rolling plant, characterized in that the roll stand has at least one guide device according to any one of the embodiment variations, preferably two guide devices.

[0024] The features, technical effects, advantages and embodiments described with respect to the guide device apply equally to the roll stand.

[0025] Particularly preferably, the roll stand has two chocks, correspondingly two work rolls supported in the chocks and forming a roll gap in which the rolled product transportable in the transport direction can be shaped, and two guide devices, in other words the work rolls are held and guided on both sides by the guide devices via corresponding chocks.

[0026] Preferably, the roll stand further comprises two backup rolls which are correspondingly capable of coming into contact with the work roll for supporting the work roll. The roll stand is therefore preferably designed as a four-roll stand (quad roll stand). However, the guide device can also be used in a six-roll stand (six-high roll stand).

[0027] Preferably, the roll stand comprises two roll housings each defining a housing window, in which on both sides of each roll housing a holding element is fixed or formed integrally with the roll housing, which holds one or more guides, the roll housings serving as a stage or frame for fixing the guide device via corresponding holding elements.

[0028] Preferably, the roll stand is configured for skin-pass rolling, where at least one of the work rolls can be equipped with a structured rolling surface. A special use of the roll stand is in skin-pass with low rolling forces. In reduction mode, the rolling forces are currently between 11000 kN and 35000 kN, whereas in skin-pass mode, a rolling force of only about 400 kN may be required. These rolling forces can be achieved by the described new bending block with three piston / cylinder units. Therefore, no original roll adjustment is used. In skin-pass mode, the upper backup roll can be lifted and the rolled product can be formed with only negative bending forces as rolling forces.

[0029] Preferably, the chocks each have two guide surfaces which are in substantially complete contact with the corresponding bending block, so that in the installed state the chocks always rest on their entire guide surfaces.

[0030] Further advantages and features of the present invention will become apparent from the following description of preferred embodiments. Any feature described therein may be implemented alone or in combination with one or more of the above features, unless these features are inconsistent. The following description of preferred embodiments is made with reference to the accompanying drawings.

[0031] Further preferred embodiments of the present invention will now be described in detail with reference to the following description of the drawings. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is a side view with a stepped section of a roll stand having a bending block for bending a work roll. [Diagram 2] FIG. 1 is a perspective view of a device for guiding a chock having a combination of upper and lower bending blocks that are adjustable relative to one another; [Diagram 3] FIG. 3 is a perspective cross-sectional view of the device according to the embodiment of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] In the following, preferred embodiments will be described with reference to the drawings, in which the same, similar or identically functioning elements are provided with the same reference numerals, and redundant descriptions of these elements will be omitted.

[0034] Figure 1 shows a roll stand 1 in the form of a stepped cross section. The roll stand 1 is used for rolling strip-shaped rolled products transportable in a transport direction (horizontal in Figure 1), in particular for rolling cold strip in cold rolling plants. The rolled products are preferably steel sheets, but other metals and alloys, such as, for example, aluminum, copper and magnesium, are also conceivable.

[0035] According to this embodiment, the roll stand 1 is designed as a four-roll stand (quadruple roll stand) having two parallel-extending and opposing work rolls 10 which form a roll gap and two corresponding backup rolls 11 which are in contact with the work rolls 10 accordingly to support them.

[0036] The work roll 10 can be provided with a flat rolling surface or can be structured, i.e. the rolling surface can have a texture that is transferred to the rolled product by rolling. During skin-pass rolling, the rolled product usually undergoes only small reductions and elongations. Skin-pass rolling can modify the mechanical properties of the rolled product, for example improving the formability (deep-draw and / or stretch forming properties) of the product. In this way, irregularities that have arisen, for example, during the annealing process or during rolling can be eliminated. In addition, by means of skin-pass rolling, the desired roughness and surface structure of the rolled product can be set by using correspondingly structured work rolls 10.

[0037] The work roll 10 is held and rotatably supported by chocks 12. The chocks 12 are, on the one hand, adapted to the work roll 10 and, on the other hand, compatible for use with bending blocks 20, which will be described in detail below, so that the roll stand 1 can be used modularly with work rolls 10 of different diameters, shapes and properties. In this sense, the chocks 12 constitute a mounting interface between the work roll 10 and the bending blocks 20.

[0038] The roll stand 1 has two roll housings 13 (only one roll housing 13 is shown in the cross-sectional view of FIG. 1), which serve as stages or frames for fixing the various components and define a housing window. In the housing window, on both sides of the roll housing 13, holding members 14 are fixed or integrally connected thereto. The holding members 14 each hold one or more guides 15, preferably formed as circular guides, i.e. as rod-shaped or cylindrical bodies.

[0039] On the guides 15, bending blocks 20 for the chocks 12 are guided. The bending blocks 20 are accordingly provided with guide bushes 21 which are in sliding contact with the guides 15. Each bending block 20 is preferably provided with an anti-twist device, for example in the form of a sliding strip, on the rear side of the bending block 20.

[0040] A distinction is made here between an upper chock 12 configured for supporting the upper work roll 10 and a lower chock 12 configured for supporting the lower work roll 10. Similarly, two lower bending blocks 20 and two upper bending blocks 20 are provided which hold the corresponding chocks on either side and guide them vertically along guides 15, respectively.

[0041] Figures 2 and 3 show in perspective views a device 2, also referred to herein as a "guiding device", for guiding the chocks 12. The guiding device 2 comprises a combination of upper and lower bending blocks 20 which are adjustable relative to one another along a guide 15. Here, Figure 3 is a cutaway perspective view in order to show in detail the arrangement of a bending actuator 30 for adjusting or shifting the bending blocks 20.

[0042] 2 and 3, it can be seen that for each device 2, ie for each combination of upper and lower bending blocks 20, there are provided a number of bending actuators 30, in this preferred embodiment just three.

[0043] The bending actuator 30 is configured to apply a bending force between the upper and lower bending blocks 20, i.e. to move the upper and lower bending blocks 20 relative to each other along the guide 15. This can be a positive bending force, in which case the bending blocks 20 are moved apart along the guide 15, so that the work rolls 10, in cooperation with the backup rolls 11, tend to bend convexly with respect to the rolling surface of the rolled product. Alternatively, a negative bending force can be applied, which moves the bending blocks 20 towards each other. Rolling under a negative bending force can be performed, for example in skin pass mode, by lifting the upper backup roll 12 (shown on the left in FIG. 1), i.e. with only a negative bending force as the rolling load, thus usually with a relatively low rolling load.

[0044] The bending actuators 30 are preferably realized as piston / cylinder units, each of which has a bending cylinder 31 in which a bending piston 32 is movably supported. The bending cylinders 31 are respectively introduced or arranged in the corresponding bending block 20, whereas the corresponding bending piston 32 is fixed to the corresponding bending block 20 via a bending piston rod 33. The actuation of the piston / cylinder units is preferably performed hydraulically. However, the bending actuators 30 can also be configured differently, for example electrically, magnetically or pneumatically.

[0045] In the cassette construction described here, the bending actuators 30 act perpendicularly on the positively guided bending blocks 20, which furthermore house the chocks 12. In the mounted state, the chocks 12 preferably rest over their entire guide surface 12a, i.e. they are in contact with the corresponding bending block 20, respectively, with substantially their entire guide surface 12a, as shown in Figure 1. Any axial shifting of the work rolls 10 is effected within the bending blocks 20, i.e. the bending system does not have to be moved together.

[0046] In this embodiment, exactly three bending actuators 30 are provided for each combination of upper and lower bending blocks 20, which can significantly increase the negative bending force. The bending actuators 30 are preferably located on the guide surface side and on a line parallel to the axial direction of the work roll 10.

[0047] In the case of three piston / cylinder units, the central piston / cylinder unit is preferably installed opposite to the outer piston / cylinder units, which allows an increased force effect when applying bending forces and also allows a particularly space-saving installation of the piston / cylinder units. Furthermore, it is possible to use only the outer piston / cylinder units or only the inner piston / cylinder units.

[0048] The piston ring side of the piston / cylinder units can also be used for power transmission. This means that negative bending forces are available from the piston face of the central piston / cylinder unit and the piston ring face of the outer piston / cylinder units, or alternatively only from the piston face of the central piston / cylinder unit. The opposite is true for positive bending.

[0049] Preferably, the bending cylinders 31 of the outer piston / cylinder units reside in the lower bending block 20 , whereas the bending cylinders 31 of the central piston / cylinder unit are mounted in the upper bending block 20 .

[0050] The roll stand 1 described here allows rolling with relatively high negative bending forces for special rolling operations. Furthermore, normal rolling applications can be carried out with positive and negative bending forces, whereby the flexibility of application of the roll stand is expanded with only minor additional constructional efforts, i.e. without special adjustment cylinders or similar systems. In addition, the bending system is particularly low-friction.

[0051] A special use of the roll stand 1 is in skin-passing at low rolling forces, for example 400 kN to 500 kN. In these low rolling force skin-passing modes, the upper backup roll 11 is raised and the rolled product is skin-passed with only negative bending forces as rolling load. For this purpose, a distance measuring system, not shown in the figures, is preferably installed in the bending block 20, so that skin-passing load control can be performed without a separate adjusting cylinder.

[0052] Where applicable, all individual features described in the embodiments can be combined with one another and / or substituted without departing from the scope of the invention. [Explanation of symbols]

[0053] 1 roll stand 2. Device for guiding the chocks 10 Work roll 11 Backup Role 12 Chock 12a Guide surface 13 Roll housing 14 Retaining member 15 Guide 20 Bending Block 21 Guide bush 30 Bending Actuator 31 Bending Cylinder 32 Bent Piston 33 Bent piston rod

Claims

1. A device (2) for guiding a chock (12) configured to support a work roll (10) forming a roll gap of a roll stand (1), comprising: The apparatus (2) comprises two bending blocks (20) each for accommodating one chock (12), at least one guide (15) for guiding the bending blocks (20) such that the bending blocks (20) are movable relative to one another along the guides (15), and a plurality of bending actuators (30) configured to move the bending blocks (20) relative to one another along the guides (15).

2. 2. The device (2) according to claim 1, characterized in that exactly three bending actuators (30) are provided.

3. 3. The device (2) according to claim 1 or 2, characterized in that the bending actuators (30) are each configured as a piston / cylinder unit having a bending cylinder (31) and a bending piston (32) supported and movable in the bending cylinder, the bending cylinder (31) being provided in one of the two bending blocks (20), while the corresponding bending piston (32) is fixed to the other bending block (20) via a bending piston rod (33).

4. 4. The device (2) according to claims 2 and 3, characterized in that the three piston / cylinder units (30) are arranged in the axial direction of the work roll (10) to include two outer piston / cylinder units (30) and one central piston / cylinder unit (30), the central piston / cylinder unit (30) being installed inversely to the outer piston / cylinder units (30).

5. 5. The device (2) according to claim 4, characterized in that both bending blocks (20) are arranged vertically one above the other in their mounting position, so that an upper bending block (20) and a lower bending block (20) are set up, the bending cylinders (31) of the outer piston / cylinder units (30) being arranged in the lower bending block (20) while the bending cylinders (31) of the central piston / cylinder unit (30) being arranged in the upper bending block (20).

6. The device (2) according to any one of claims 1 to 5, characterized in that the bending block (20) is provided with at least one guide bush (21), preferably two guide bushes (21), each in sliding contact with a corresponding guide (15).

7. Device (2) according to any one of the preceding claims, characterised in that at least two guides (15) are provided.

8. Device (2) according to any one of the preceding claims, characterised in that the guide or guides (15) are formed as circular guides.

9. A roll stand (1) for rolling strip-shaped rolled products, preferably for rolling cold strip in a cold rolling plant, characterized in that the roll stand (1) comprises at least one device (2) according to any one of claims 1 to 8.

10. 10. The roll stand (1) according to claim 9, characterized in that the roll stand comprises two chocks (12), two work rolls (10) supported in the chocks and forming a roll gap in which a rolled product transportable in the transport direction can be shaped, and two devices (2) according to any one of claims 1 to 10, the roll stand (1) preferably further comprising two backup rolls (11) which can be brought into contact with the work rolls (10) accordingly.

11. 11. The roll stand (1) according to claim 9 or 10, characterized in that the roll stand comprises two roll housings (13) each defining a housing window, and in the housing windows on both sides of the roll housings (13) a holding element (14) is fixed or formed integrally with the roll housings, the holding element (14) holding one or more guides (15).

12. 12. The roll stand (1) according to any one of claims 9 to 11, characterized in that the roll stand is configured for skin pass rolling, preferably in that at least one of the work rolls (10) is provided with a structured rolling surface.

13. 13. A roll stand (1) according to any one of claims 9 to 12, characterized in that the chocks (12) each have two guide surfaces (12a), each of which is in substantially complete contact with the corresponding bending block (20).

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