Rolling mill assembly for transmitting high torques

Abstract

The invention relates to a rolling mill assembly (1) comprising two cardan shafts (4, 5) which are each connected to a drive device (13, 14), wherein the first rolling mill-side joint (6) is at a first distance (10) from the first working roller (2) and the second rolling mill-side joint (7) is at a second distance (11) from the second working roller (3), wherein the first and second distances (10, 11) differ by 0.5 m to 4 m, and, in at least one cardan shaft (4, 5), a device (12) for changing the length is located between the rolling mill-side joint (6, 7) and the working roller (2, 3).

Description

[0001] Rolling mill arrangement for transmitting high torques

[0002] The invention relates to a rolling mill arrangement comprising a first work roll and a second work roll, wherein the work rolls are each connected to a cardan shaft, which in turn are each connected to a drive device, wherein the two cardan shafts each comprise a roll-side joint and a drive-side joint.

[0003] EP 3227578 B1 is known from the prior art, which describes a cardan shaft that can telescopically adjust its length. Use in a rolling mill with two cardan shafts and corresponding provisions for operating adjacent cardan shafts is not described.

[0004] Furthermore, JP 2013 136070 is known from the prior art, which describes two parallel-arranged cardan shafts, each comprising a device for changing the length, wherein the devices for changing the length are also arranged parallel to one another.

[0005] Furthermore, DE 10316261 is known from the prior art, which also shows two cardan shafts with shaft journals for length adjustment. Here, too, the length adjustment devices are arranged parallel to each other.

[0006] In an arrangement as known in the art, in which the roll-side joints are arranged directly above one another, the roll-side joints can have a maximum of the same diameter as the work rolls, since the upper and lower rolls have only a minimal or no roll gap when rolling thin sheets and during sizing. Due to this limitation, roll-side joints have the greatest risk of failure. With a staggered arrangement of the joints, corresponding shaft pieces, so-called "spacers", are used in the prior art to create space for the joints, whereby the roll arrangement becomes longer overall. The object of the invention is to provide a particularly compact rolling mill arrangement with improved torque capacity of the cardan shafts in order to be able to transmit high torques from the drive to the work rolls.The cardan shafts usually have the greatest risk of failure at the roll-side joints; therefore, the object of the invention is to provide a rolling mill arrangement that allows the installation of roll-side joints with a greater torque capacity.

[0007] The object is achieved according to the invention by an embodiment according to the independent claim. Further advantageous embodiments of the present invention can be found in the subclaims.

[0008] The object is achieved according to the invention with a rolling mill arrangement, wherein the first roll-side joint has a first distance from the first work roll and the second roll-side joint has a second distance from the second work roll, wherein the first and the second distances differ by 0.5 m to 4 m, and wherein in at least one cardan shaft a device for changing the length is arranged between the roll-side joint and the work roll, and in the other cardan shaft a further device for changing the length is arranged between the roll-side joint and the drive-side joint.

[0009] The different spacing advantageously allows the joints to be arranged next to one another. The joints of the cardan shaft require a larger design than shafts and / or length-adjusting devices in order to transmit the same torque without exceeding their own load limit. In the prior art, the joints are arranged in parallel, so the joint diameter cannot be larger than the roll diameter, as otherwise the two roll-side joints would collide. By using a shaft or length-adjusting device with a smaller diameter than the work roll diameter, space is created to arrange a larger roll-side joint. The use of a length-adjusting device is important for the cardan shaft in order to compensate for changes in the roll position without these being passed on to the drive as constraining forces.Length changes in the work rolls of the rolling stand can be caused by thermal expansion. Active movement of the work rolls along the rotational axis is also possible, particularly to compensate for skew and thickness differences across the width of the rolled stock during the rolling process.

[0010] A length-changing device can telescopically change the length along the axis, either under load or in the unloaded state. The length-changing device is also known as a telescopic function, telescopic shaft, or length compensation.

[0011] A rolling mill arrangement is also advantageous, wherein the device for changing the length is arranged on the lower joint shaft between the lower roll-side joint and the lower work roll.

[0012] The length of the length-changing device, its own weight, the weight of the cardan shaft, and / or the weight of the roll-side joint, results in a bending moment and resulting material loads, particularly at the connecting hub, where the length-changing device is located outside the two joints between the work roll and the roll-side joint. The bending occurs in the direction of gravity.

[0013] This bending can be detrimental to the material stress on the connecting device between the roll-side joint and the work roll and / or the length-changing device. Another advantageous effect of the arrangement on the lower shaft is better accessibility and the possibility of attaching a support device.

[0014] A rolling mill arrangement is also advantageous in which the device for changing the length is supported by means of a support device.

[0015] A support device can advantageously counteract the described bending. The support device advantageously comprises a roller that is pressed against the surface of the length-changing device, wherein the pressing force is selected such that bending is at least largely compensated. This support device can also contain a plurality of rollers that jointly perform the supporting function and, if necessary, guide the length-changing device laterally or completely circumferentially on the axis of rotation. Furthermore, several support rollers can be arranged one behind the other in the axial direction in order to evenly reinforce the supporting function. The support device is advantageously designed as a support spindle and advantageously comprises at least one rolling bearing to absorb the introduced supporting forces.The rolls of the support spindle are advantageously smaller than the press rolls of the rolling mill arrangement and usually have a diameter of 10 - 40% of the press rolls.

[0016] Also advantageous is a rolling mill arrangement, wherein the rolling mill arrangement comprises a further device for changing the length, wherein the further device for changing the length is arranged between the two joints of the cardan shaft which does not have a device for changing the length between the roll-side joint and the work roll.

[0017] As is known in the prior art, it is common practice for both cardan shafts in a rolling mill arrangement to have a length compensation device. In contrast to the prior art, however, only one of these length-adjusting devices is arranged between the joints of the cardan shaft. A rolling mill arrangement is also advantageous in which at least one of the roll-side joints has a diameter 3% to 30% larger than the diameter of the connected work roll.

[0018] The diameter of the joints refers to the largest dimension of the joint perpendicular to at least one axis of rotation, the enveloping circle. In the case of cardan shafts, the diameter can theoretically be increased by deflecting the cardan shaft, since the deflection causes part of the joint to follow a different axis of rotation and thus takes up more space in one direction. However, this is usually avoided by appropriately shaping the joint forks by rounding them centrally to the pivot point of the joint.

[0019] The roll gap is encompassed in its extension as an imaginary line of the so-called pass line, which marks the support surface of the area through which the rolled stock passes the rolling mill assembly. In an advantageous embodiment of the invention, at least one roll-side joint, preferably the lower one, can extend beyond the pass line.

[0020] Furthermore, a rolling mill arrangement is advantageous, wherein the diameter (DG) of the roll-side joints is in the range of 40 cm to 150 cm, wherein the cardan shaft is suitable for transmitting a torque of 200 knm to 15,000 knm.

[0021] Providing a rolling mill arrangement with high torque capacity of the cardan shafts can be achieved by using larger joints. However, the design effort and the larger joints only make economic sense if the rolling mill arrangement must transmit high torques. This is particularly the case for rolling mills for metalworking and / or sheet metal production. Therefore, it is particularly advantageous for use with torques of 400–15,000 kNm and diameters in the range of 50–130 cm. A rolling mill arrangement in which both cardan shafts are each supported by at least one support device is also advantageous.

[0022] The use of at least one support spindle can reduce bending or at least reduce the bending moment at the connecting hubs. An arrangement of several support spindles on the drive shafts can also be advantageous in order to relieve the connecting hub and the spherical plain bearings of all drive shafts from high weight forces and the resulting bending moments.

[0023] A rolling mill arrangement is also advantageous, wherein the device for changing the length comprises an inner shaft body and an outer hub, wherein the shaft body has a toothing and the hub has a counter toothing.

[0024] The design of the length-changing device should enable a telescopic length change with as little friction as possible, while simultaneously ensuring efficient and high torque transmission. The length change must also allow for minimal play; gearing parallel to the rotation axis has proven particularly advantageous in this regard.

[0025] A rolling mill arrangement is also advantageous in which the drive shafts comprise universal joints. A rolling mill arrangement is also advantageous in which the drive shafts comprise flat-pin joints or toothed coupling joints.

[0026] Depending on the size of the invention, the joints are advantageously designed either as universal joints, flat-pin joints, or gear coupling joints. Other types of cardan shafts cannot withstand the stresses of a rolling mill arrangement for metalworking.

[0027] The invention is explained below with reference to the figures. The figures show in detail: Fig.1 A schematic representation of the prior art

[0028] Fig.2 A schematic representation with aspects of the invention

[0029] Figure 1 shows a not-to-scale schematic representation of a rolling mill arrangement 1 from the prior art. The rolling mill comprises a first work roll 2 and a second work roll 3 which are suitable for rolling rolled stock, in particular metal workpieces, in a roll gap. The roll gap is shown in the extension as a dashed line of the so-called pass line 21. The work rolls 2, 3 are connected to the first drive device 13 and the second drive device 14 by means of a first cardan shaft 4 and a second cardan shaft 5. The cardan shafts each comprise a roll-side joint 6, 7, a length-changing device 12, and a drive-side joint 8, 9. In both cardan shafts 4, 5, the length-changing device 12 is arranged between the roll-side joint 6, 7 and the drive-side joint 8, 9. No part of the cardan shaft 4, 5 can protrude beyond the pass line, as this would otherwise result in a collision between the cardan shafts.All joints have a smaller diameter compared to the diameter of the work rolls 2.3.

[0030] Figure 2 shows a not-to-scale schematic representation of a rolling mill arrangement 1 with features of the invention. The rolling mill comprises a first work roll 2 and a second work roll 3, which are suitable for rolling rolled stock, in particular metal workpieces, in a roll gap. The roll gap is shown in the extension as a dashed line of the so-called pass line 21. The work rolls 2, 3 are connected to the first drive device 13 and the second drive device 14 by means of a first cardan shaft 4 and a second cardan shaft 5. The cardan shafts each comprise a roll-side joint 6, 7, a length-changing device 12, and a drive-side joint 8, 9. In the first cardan shaft 4, the first roll-side joint 6 is connected to the first work roll 2 at a first distance 10. The second work roll 3 is first connected to a length-changing device 12 and then to the second roll-side joint 7.Optionally, the rolling mill arrangement 1 is arranged with respect to the force of gravity g as shown in the diagram, wherein the second cardan shaft 5 is then the lower cardan shaft 16. Analogously, the second roll-side joint 7 is then the lower roll-side joint 17 and the second work roll 3 is the lower work roll 18. The device for changing the length, which is arranged between the second work roll 3, 18 and the roll-side joint 7, 17, is supported in Figure 2 by means of a support device 15. The support device 15 is shown merely as an active support roll, but can comprise at least one bearing, in particular by means of rolling bearings and a holder, in particular an adjustable holder. The support device can also comprise a plurality of support rolls or support spindles (not shown in the diagram), wherein the axes of rotation of the support device 15 run parallel to the axis of rotation of the work roll or of the supported device for changing the length 12.The second distance 11 is shown as the distance between the second or lower working roll 3, 18 and the roll-side or lower joint 7, 17. The offset arrangement of the two roll-side joints 6, 7 creates sufficient space for the roll-side joints 6, 7 to extend beyond the pass line 21 without colliding with the other drive shaft.

[0031] List of reference symbols

[0032] 1 rolling mill arrangement

[0033] 2 first work roll

[0034] 3 second work roll

[0035] 4 first drive shaft

[0036] 5 second drive shaft

[0037] 6 first roller-side joint

[0038] 7 second roller-side joint

[0039] 8 first drive-side joint

[0040] 9 second drive-side joint

[0041] 10 first distance

[0042] 11 second distance

[0043] 12 Device for changing the length

[0044] 13 first drive device

[0045] 14 second drive device

[0046] 15 Support device

[0047] 16 lower drive shaft

[0048] 17 lower roller-side joint

[0049] 18 lower work roll

[0050] 19 shaft bodies

[0051] 20 Hub

[0052] 21 Pass-Line g gravity

[0053] DG joint diameter

[0054] Dw roller diameter

Claims

Patent claims 1 . Rolling mill arrangement (1) comprising a first work roll (2) and a second work roll (3), wherein the work rolls (2, 3) are each connected to a cardan shaft (4, 5), which in turn are each connected to a drive device (13, 14), wherein the two cardan shafts (4, 5) each comprise a roll-side joint (6, 7) and a drive-side joint (8, 9), characterized in that the first roll-side joint (6) has a first distance (10) from the first work roll (2) and the second roll-side joint (7) has a second distance (11) from the second work roll (3), wherein the first and the second distances (10, 11) differ by 0.5 m to 4 m, and wherein in at least one cardan shaft (4, 5) a device for changing the length (12) is arranged between the roll-side joint (6, 7) and the work roll (2, 3) and the other cardan shaft (4, 5) a further device for changing the length (12) between the roller-side joint (6,7) and drive-side joint (8, 9).

2. Rolling mill arrangement (1) according to claim 1, characterized in that the device for changing the length (12) is arranged on the lower joint shaft (16) between the lower roll-side joint (17) and the lower work roll (18).

3. Rolling mill arrangement (1) according to claim 1 or 2, characterized in that at least one device for changing the length (12) is supported by means of a support device (15).

4. Rolling mill arrangement (1) according to one of the preceding claims, characterized in that the rolling mill arrangement (1) comprises a further device for changing the length (12), wherein the further device for changing the length (12) is arranged between the two joints (6, 8 or 7, 9) of the cardan shaft (4, 5) which does not have Device for changing the length (12) between the roll-side joint (6, 7) and the work roll (2, 3). Rolling mill arrangement (1) according to one of the preceding claims, characterized in that at least one of the roll-side joints (6, 7) has a diameter (DG) that is 3% to 30% larger than the diameter (Dw) of the connected work roll (2, 3). Rolling mill arrangement (1) according to one of the preceding claims, characterized in that the diameter (DG) of the roll-side joints is in the range of 40 cm to 150 cm, wherein the cardan shaft (4, 5) is suitable for transmitting a torque of 200 kNm to 15,000 kNm. Rolling mill arrangement (1) according to one of the preceding claims, characterized in that both cardan shafts (4, 5) are each supported by at least one support device (15).Rolling mill arrangement (1) according to one of the preceding claims, characterized in that the device for changing the length (11) comprises an inner shaft body (19) and an outer hub (20), wherein the shaft body (19) has a toothing and the hub (20) has a counter-toothing. Rolling mill arrangement (1) according to one of the preceding claims, characterized in that the universal joints (4, 5) comprise universal joints. Rolling mill arrangement (1) according to one of the preceding claims, characterized in that the universal joints (4, 5) comprise flat-pin joints or toothed coupling joints.

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