Rolling Mill Arrangement for Transmitting High Torques

Description

[0001] 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.

[0002] Prior art EP 3227578 B1 describes a drive shaft whose length can change telescopically. However, its use in a roller stand with two drive shafts and corresponding provisions for operating drive shafts arranged side by side is not described.

[0003] Furthermore, JP 2013 136070 is known from the prior art, which describes two parallel drive shafts, each comprising a device for changing length, wherein the devices for changing length are also arranged parallel to each other.

[0004] Furthermore, DE 10316261 is known from the prior art, which also shows two cardan shafts with journals for length adjustment. Here too, the length adjustment devices are arranged parallel to each other and between the drive-side and roller-side joints of the cardan shafts.

[0005] In a prior art arrangement where the roll-side joints are arranged directly above one another, the maximum diameter of the roll-side joints can be the same as that of the work rolls, since the upper and lower rolls have only a minimal or no roll gap when rolling thin sheets and during calibration. Due to this limitation, roll-side joints have the greatest risk of failure. In a staggered arrangement of the joints, corresponding shaft sections, so-called "spacers," are used in the prior art to create space for the joints, thereby increasing the overall length of the roll assembly.

[0006] The object of the invention is to provide a particularly compact rolling mill arrangement with improved torque capacity of the drive shafts in order to transmit high torques from the drive to the work rolls. Drive shafts typically have the greatest risk of failure at the roll-side joints; therefore, it is also an object of the invention to provide a rolling mill arrangement that allows the installation of roll-side joints with a higher torque capacity.

[0007] The problem is solved according to the invention by an embodiment according to the independent claim. Further advantageous embodiments of the present invention are found in the dependent claims.

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

[0009] The varying spacing advantageously allows the joints to be arranged side by side. The joints of the driveshaft require a larger design compared to shafts and / or length-changing devices in order to transmit the same torque without exceeding their own load limit. In the prior art, the joints are arranged parallel to each other, so the joint diameter cannot be larger than the roller diameter, as the two roller-side joints would otherwise collide.

[0010] By using a shaft or length-changing device with a smaller diameter compared to the work roll diameter, space is created to accommodate a larger joint on the roll side. The use of a length-changing device is important for the drive shaft to compensate for changes in roll position without transmitting these as constraint forces to the drive. Length changes in the work rolls of the rolling stand can be caused by thermal expansion. Furthermore, active displacement of the work rolls along the axis of rotation is possible, particularly to compensate for misalignment and thickness variations across the width of the material being rolled during the rolling process.

[0011] A device for changing length can telescopically alter its length along the axis, either under load or in an unloaded state. This device is also known as a telescopic function, telescopic shaft, or length compensation device.

[0012] A further advantage is a rolling mill arrangement in which the device for changing the length is arranged on the lower drive shaft between the lower roller-side joint and the lower work roll.

[0013] The length of the length-changing device, its own weight, the weight of the drive shaft and / or the weight of the roller-side joint, results in a bending moment and subsequent material stresses, particularly at the connecting hub, where the length-changing device is located outside the two joints between the work roller and the roller-side joint. The bending occurs in the direction of gravity.

[0014] This bending can be detrimental to the material stress on the connecting device between the roller-side joint and the work roller and / or the length-changing device. A further advantage of the arrangement on the lower shaft is improved accessibility and the possibility of attaching a support device.

[0015] Furthermore, a rolling mill arrangement is advantageous in which the device for changing length is supported by means of a support device.

[0016] 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, the pressing force being selected such that the bending is at least largely compensated. This support device can also contain multiple rollers that together perform the support function and, if necessary, guide the length-changing device laterally or completely around its axis of rotation. Furthermore, several support rollers can be arranged one behind the other in the axial direction to uniformly reinforce the support function. The support device is advantageously designed as a support spindle and advantageously includes at least one rolling bearing to absorb the applied support forces.The rollers of the support spindle are advantageously smaller than the press rollers of the rolling mill arrangement, and typically have a diameter of 10-40% of the press rollers.

[0017] A further advantage is a rolling mill arrangement, wherein the rolling mill arrangement comprises a further device for changing length, wherein the further device for changing length is arranged between the two joints of the cardan shaft which does not have a device for changing length between the roll-side joint and the work roll.

[0018] As is known in the prior art, it is common practice in rolling mill arrangements for both drive shafts to have a device for length compensation. However, unlike the prior art, only one of these devices for length adjustment between the joints of the drive shaft is arranged here.

[0019] A further advantage is a rolling mill arrangement in which at least one of the roll-side joints has a diameter that is 3% to 30% larger compared to the diameter of the connected work roll.

[0020] The diameter of the joints refers to the largest dimension of the joint perpendicular to at least one axis of rotation, the circumscribed circle. In the case of drive shafts, the diameter can theoretically be increased by deflecting the drive shaft, since the deflection causes part of the joint to follow a different axis of rotation and thus occupy more space in that direction. However, this is usually avoided by appropriately shaping the joint yokes by rounding them off centrally to the pivot point of the joint.

[0021] The roll gap is defined, in its extension, as an imaginary line of the so-called pass line, which marks the contact surface of the area through which the rolled material passes the rolling mill assembly. In an advantageous embodiment of the invention, at least one roll-side joint, preferably the lower one, can project beyond the pass line.

[0022] A further advantage is a rolling mill arrangement wherein the diameter (DG ) of the roller-side joints is in the range of 40 cm to 150 cm, wherein the drive shaft is suitable to transmit a torque of 200 kNm to 15,000 kNm.

[0023] Providing a rolling mill assembly with high torque capacity for the drive shafts can be achieved through larger joints. However, the increased design effort and the larger joints are only economically viable if the rolling mill assembly has to transmit high torques. This is particularly the case for rolling mills used in metalworking and / or sheet metal production. Therefore, their use is especially advantageous for torques of 400–15,000 kNm and diameters in the range of 50–130 cm.

[0024] A further advantage is a rolling mill arrangement in which both cardan shafts are each supported by means of at least one support device.

[0025] The use of at least one support spindle can reduce bending or at least the bending moment at the connecting hubs. Furthermore, an arrangement of several support spindles on the drive shafts can be advantageous in relieving the connecting hub and the spherical bearings of all drive shafts from high weight forces and the resulting bending moments.

[0026] A further advantage is a rolling mill arrangement wherein the device for changing length comprises an inner shaft body and an outer hub, wherein the shaft body has a toothed section and the hub has a mating section.

[0027] The design of the length-changing device should enable a telescopic length change with minimal friction, while simultaneously ensuring efficient transmission of high torques. The length change should also ideally involve very little play; a gear parallel to the axis of rotation has proven particularly advantageous in this regard.

[0028] A further advantageous rolling mill arrangement is one in which the drive shafts comprise universal joints. A further advantageous rolling mill arrangement is one in which the drive shafts comprise flat pin joints or gear coupling joints.

[0029] 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 loads of a rolling mill setup for metalworking.

[0030] The invention will be explained below with the aid of figures. The figures show, in detail: Fig. 1 A schematic representation of the prior art. Fig. 2 A schematic representation showing aspects of the invention.

[0031] Figure 1Figure 1 shows a schematic representation, not to scale, 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 material, in particular metal workpieces, in a roll gap. The roll gap is shown as the 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 drive shaft 4 and a second drive shaft 5. The drive shafts each comprise a roll-side joint 6, 7, a length-changing device 12, and a drive-side joint 8, 9. On both drive 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 drive shaft 4, 5 can protrude beyond the pass line, as this would otherwise cause a collision between the drive shafts.All joints have a smaller diameter compared to the diameter of the work rollers 2.3.

[0032] Figure 2Figure 1 shows a non-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 material, in particular metal workpieces, in a roll gap. The roll gap is shown as a dashed line, 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 drive shaft 4 and a second drive shaft 5. The drive shafts each comprise a roll-side joint 6, 7, a length-changing device 12, and a drive-side joint 8, 9. In the first drive 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 gravity g as shown in the illustration, wherein the second drive shaft 5 is then the lower drive shaft 16. Similarly, 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 length-changing device, which is arranged between the second work roll 3, 18 and the roll-side joint 7, 17, is shown in the illustration. Figure 2supported by a support device 15. The support device 15 is shown here only as an active support roller, but can include at least a bearing, in particular by means of a rolling bearing, and a bracket, in particular an adjustable bracket. The support device can also, not shown in the illustration, include several support rollers or support spindles, wherein the axes of rotation of the support device 15 run parallel to the axis of rotation of the work roller or the supported device for length change 12. The second distance 11 is shown as the distance between the second or lower work roller 3, 18 and the roller-side or lower joint 7, 17. Due to the offset arrangement of the two roller-side joints 6, 7, sufficient space is created so that the roller-side joints 6, 7 can project beyond the pass line 21 without colliding with the respective other drive shaft. Reference symbol list

[0033] 1 Rolling mill assembly 2 First work roll 3 Second work roll 4 First drive shaft 5 Second drive shaft 6 First roll-side joint 7 Second roll-side joint 8 First drive-side joint 9 Second drive-side joint 10 First gap 11 Second gap 12 Length change device 13 First drive device 14 Second drive device 15 Support device 16 Lower drive shaft 17 Lower roll-side joint 18 Lower work roll 19 Shaft body 20 Hub 21 Pass line gGravity DG Joint diameter DW Roller diameter

Claims

1. A 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 drive shaft (4, 5), which in turn are each connected to a drive device (13, 14), wherein the two drive shafts (4, 5) each comprise a roll-side joint (6, 7) and a drive-side joint (8, 9), characterised in that the first roller-side joint (6) has a first distance (10) from the first working roller (2) and the second roller-side joint (7) has 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 wherein, in at least one drive shaft (4, 5), a length-adjustment device (12) is arranged between the roller-side joint (6, 7) and the working roller (2, 3), and on the other drive shaft (4, 5) a further device for adjusting the length (12) is arranged between the roller-side joint (6, 7) and the drive-side joint (8, 9).

2. A rolling mill arrangement (1) according to claim 1, characterised in that the length adjustment device (12) is arranged on the lower drive shaft (16) between the lower roller-side joint (17) and the lower work roll (18).

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

4. A rolling mill arrangement (1) according to one of the preceding claims, characterised in that the rolling mill arrangement (1) comprises a further length-adjustment device (12), wherein the further length-adjustment device (12) is arranged between the two joints (6, 8 or 7, 9) of that drive shaft (4, 5) which does not have a length-adjustment device (12) between the roll-side joint (6, 7) and the work roll (2, 3).

5. A rolling mill arrangement (1) according to one of the preceding claims, characterised 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).

6. A rolling mill arrangement (1) according to one of the preceding claims, characterised in that the diameter (DG) of the roller-side joints is in the range of 40 cm to 150 cm, wherein the drive shaft (4, 5) is capable of transmitting a torque of 200 kN·m to 15,000 kN·m.

7. Rolling mill arrangement (1) according to one of the preceding claims, characterised in that both drive shafts (4, 5) are each supported by means of at least one support device (15).

8. A rolling mill arrangement (1) according to one of the preceding claims, characterised in that the length-adjustment device (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 mating toothing.

9. Rolling mill arrangement (1) according to one of the preceding claims, characterised in that the drive shafts (4, 5) comprise universal joints.

10. Rolling mill arrangement (1) according to one of the preceding claims, characterised in that the articulated shafts (4, 5) comprise spline joints or toothed coupling joints.