ROLLING MILL ASSEMBLY FOR TRANSMITTING HIGH TORQUES

Abstract

A rolling mill assembly includes: a first cardan shaft including a first rolling mill-side joint and a first drive-side joint, a second working roller being connected to a second cardan shaft, which in turn is connected to a second drive device, the second cardan shaft including a second rolling mill-side joint and a second drive-side joint, the first rolling mill-side joint being located at a first distance to the first working roller, the second rolling mill-side joint being located at a second distance to the second working roller, the first distance and the second distance differing by 0.5 m to 4 m, the first cardan shaft further including a first device configured for length change between the first rolling mill-side joint and the first drive-side joint, the second cardan shaft further including a second device configured for length change between the second rolling mill-side joint and the second working roller.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a rolling mill assembly.

2. Description of the Related Art

EP 3227578 B1 is known from the state of the art and describes a cardan shaft that can change telescopically in length. An application in a roll stand with two cardan shafts and appropriate arrangements for operating cardan shafts arranged next to one another is not described.

Also known from the state of the art is JP 2013 136070 which describes two cardan shafts arranged parallel to each other, each including a device for length change, wherein the devices for length change are also arranged parallel to one another.

Also known from the state of the art is DE 10316261 which also shows two cardan shafts with shaft journals for length change. The devices for length change are arranged parallel to one another also in this arrangement.

In an arrangement—as known from the state of the art—in which the rolling mill-side joints are arranged directly above one another, the rolling mill-side joints can—as a maximum—have the same diameter as the working rollers, since the upper and lower rollers have only a minimal, or no roller gap at all when rolling thin metal sheets and during calibration. Due to this limitation, joints on the rolling mill side have the greatest risk of failure. In an offset arrangement of the joints, corresponding shaft segments—so-called “spacers”—are used in the state of art to create space for the joints, wherein the roller arrangement becomes longer overall.

What is needed in the art is an especially compact rolling mill assembly with improved torque capacity of the cardan shafts in order to be able to transmit high torques from the drive to the working rollers. The cardan shafts generally represent the greatest risk of failure at the rolling mill-side joints. Thus, what is also needed in the art is a rolling mill assembly that allows the installation of rolling mill-side joints with a greater torque capacity.

SUMMARY OF THE INVENTION

The present invention relates to a rolling mill assembly including a first working roller and a second working roller, wherein the working rollers are each connected to a cardan shaft, which in turn are connected to a drive device, wherein the two cardan shafts respectively include a rolling mill-side joint and a drive-side joint.

The present invention provides a rolling mill assembly (1) including a first working roller (2) and a second working roller (3), wherein the working rollers (2, 3) are each connected to a cardan shaft (4, 5), which in turn are connected to a drive device (13, 14), wherein the two cardan shafts (4, 5) respectively include a rolling mill-side joint (6, 7) and a drive-side joint (8, 9), characterized in that the first rolling mill-side joint (6) is located at a first distance (10) to the first working roller (2) and the second rolling mill-side joint (7) is located at a second distance (11) to the second working roller (3), wherein the first and second distances (10, 11) differ by 0.5 m to 4 m, and wherein at least on one cardan shaft (4, 5) a device for length change (12) is arranged between the rolling mill-side joint (6, 7) and the working roller (2, 3), and wherein at the other cardan shaft (4, 5) another device for length change (12) is arranged between the rolling mill-side joint (6, 7) and the drive-side joint (8, 9). Stated another way, according to the present invention, the present invention provides a rolling mill assembly, wherein the first rolling mill-side joint is located at a first distance to the first working roller and the second rolling mill-side joint is located at a second distance to the second working roller, wherein the first and second distances differ by 0.5 m to 4 m, and wherein at least on one cardan shaft a device for changing the length is arranged between the rolling mill-side joint and the working roller, and wherein at the other cardan shaft a further device for changing the length is arranged between the rolling mill-side joint and the drive-side joint.

The different distance advantageously makes it possible that the joints can be arranged next to each other. The joints of the cardan shaft require a larger design compared to shafts and/or devices for changing length in order to transmit the same torque without exceeding their own load limit. In the state of the art, the joints are arranged in parallel. Thus, the joint diameter cannot be larger than the roller diameter, as the two rolling mill-side joints would otherwise collide.

By using a shaft or device for length change that has a smaller diameter compared to the working roll diameter, space is created to position a larger rolling mill-side joint. The use of a device for length change is important for the cardan shaft to compensate for changes in the roller position without these being passed on to the drive as constraining forces. The changes in length in the working rollers of the roll stand can be caused by thermal expansion. In addition, it is possible to actively move the working rollers along the axis of rotation, in particular to compensate for tilting and differences in thickness across the width of the rolled material during the rolling process.

A device for length change can change the length along the axis telescopically under load or in a load-free state. The device for length change is also known as a telescopic function, telescopic shaft, or length compensation.

Moreover, advantageous is a rolling mill assembly, wherein the device for length change is arranged on the lower cardan shaft between the lower rolling mill-side joint and the lower working roller.

The length of the length-changing device, its own weight, the weight of the cardan shaft and/or the weight of the rolling mill-side joint result in a bending moment and material stresses resulting therefrom, particularly at the connecting hub, where the length-changing device is located outside the two joints between the working roller and the rolling mill-side joint. Bending occurs thereby in the direction of gravity.

This bending can be detrimental in regard to material stress on the connecting device between the rolling mill-side joint and the working roller and/or the device for changing the length. An additional advantageous effect of the arrangement on the lower shaft is better accessibility and the possibility of being able to install a support device for support.

Also advantageous is a rolling mill assembly wherein the device for changing the length is supported by way of a support device.

A support device can advantageously counteract the described bending. The support device advantageously includes a roller that is pressed against the surface of the device for length change, wherein the pressing force is selected such that bending is at least extensively compensated. This support device can also include a plurality of rollers, which jointly perform the support function and guide the device for changing length, if necessary, laterally or completely circumferentially on the axis of rotation. Furthermore, a number of support rollers can also be arranged one behind the other in axial direction in order to uniformly reinforce the support function. The support device is advantageously designed as a support spindle, and advantageously includes at least one roller bearing to absorb the applied support forces. The rollers of the support spindle are advantageously smaller than the press rollers of the rolling mill assembly, and usually have a diameter of 10-40% of that of the press rollers.

Also advantageous is a rolling mill assembly in which the rolling mill assembly includes an additional device for length change, wherein the additional device for length change is arranged between the two joints of the particular cardan shaft which does not have a device for length change between the rolling mill-side joint and the working roll.

As is known from the state of the art, it is usual for both cardan shafts in the rolling mill assembly to have a device for length compensation. In contrast to the state of the art, however, only one of these devices for changing the length is arranged between the joints of the cardan shaft.

Also advantageous is a rolling mill assembly in which at least one of the rolling mill-side joints has a diameter that is 3% to 30% larger than the diameter of the connected working roller.

The diameter of the joints describes the largest dimension of the joint perpendicular to at least one axis of rotation, as the enveloping circle. On 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, thus taking up more space in one direction. However, this is usually avoided by shaping the joint forks accordingly by rounding them centrally to the pivot point of the joint.

The roll gap is included in the extension as an imaginary line of the so-called pass line, which characterizes the support surface of the area through which the rolling stock passes through the rolling mill assembly. In one advantageous embodiment of the present invention, at least one rolling mill-side joint—optionally the lower one—can protrude beyond the pass line.

Also advantageous is a rolling mill assembly in which diameter (D_G) of the rolling mill-side joints is in the range 40 cm to 150 cm, whereby the cardan shaft is suitable for transmitting a torque of 200 knm to 15.000 knm.

Provision of a rolling mill assembly having a high torque capacity of the cardan shafts can be achieved through larger joints. However, the design effort and the larger joints are only economically viable if the rolling mill assembly must transmit high torques. This is the case in particular with rolling mills for metal processing and/or sheet metal production. It is therefore particularly beneficial to use them for torques of 400-15.000 knm, and diameters in the range of 50-130 cm.

Also advantageous is a rolling mill assembly, wherein both cardan shafts respectively are supported by way of at least one support device.

The use of at least one support spindle can reduce bending or at least reduce the bending moment on the connecting hubs. An arrangement of a number of support spindles on the cardan shafts can also be advantageous to relieve the connecting hub and the spherical bearings of all cardan shafts of high weight forces and the bending moments resulting therefrom.

Also advantageous is a rolling mill assembly, wherein the device for changing the length includes an inner shaft body and an outer hub, wherein the shaft body has splines, and the hub has mating splines.

The design of the device for length change should enable a telescopic length change with as little friction as possible, while at the same time ensuring efficient transmission of high torques. The change in length should also allow for only a small amount of play, and splines parallel to the axis of rotation have proven to be particularly advantageous.

Also advantageous is a rolling mill assembly in which the cardan shafts include cross joints. Moreover, advantageous is a rolling mill assembly, wherein the cardan shafts include trunnion joints or gear coupling joints.

Depending on the size of the inventive unit, the joints can advantageously be designed either as cardan joints, trunnion joints or gear coupling joints. Other types of cardan shafts cannot withstand the loads of a rolling mill assembly for metal processing.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic representation of the state of the art; and

FIG. 2 is a schematic representation with aspects of the present invention.

Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate at least one embodiment of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a schematic representation of a rolling mill assembly 1 from the state of the art, which is not to scale. The rolling mill includes a first working roll 2 and a second working 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. Working rollers 2, 3 are connected to first drive device 13 and second drive device 14 by way of a first cardan shaft 4 and a second cardan shaft 5. The cardan shafts each include a rolling mill-side joint 6, 7, a device 12 for changing the length and a drive-side joint 8, 9. In both cardan shafts 4, 5, device for length change 12 is arranged between rolling mill-side joint 6, 7 and drive-side joint 8, 9. No part of cardan shaft 4, 5 can protrude beyond the pass line, since this would cause the cardan shafts to collide. All joints have a smaller diameter compared to the diameter of working rollers 2, 3.

FIG. 2 is a representation of a rolling mill assembly 1 which is not to scale, showing features of the present invention. The rolling mill includes a first working roller 2 and a second working roller 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. Work rollers 2, 3 are connected to first drive device 13 and second drive device 14 by way of a first cardan shaft 4 and a second cardan shaft 5. The cardan shafts each include a rolling mill-side joint 6, 7, a length change device 12 and a drive-side joint 8, 9. On first cardan shaft 4, first rolling mill-side joint 6 is connected to first working roller 2 at a first distance 10. Second working roller 3 is initially connected to a length-changing device 12 and then to second rolling mill-side joint 7. Rolling mill assembly 1 is arranged optionally relative to gravity g as shown in the illustration, with second cardan shaft 5 then being the lower cardan shaft 16. Analogously, second rolling mill-side joint 7 is then the lower rolling mill-side joint 17 and second working roller 3 is lower work roller 18. The device for length change, which is arranged between second working roller 3, 18 and rolling mill-side joint 7, 17, is supported in FIG. 2 by a support device 15. Support device 15 is shown here as only an active support roller, but can include at least one bearing arrangement, in particular by way of rolling bearings, and a mounting, in particular an adjustable mounting. The support device can also include several support rollers or support spindles which are not shown in the illustration, wherein the axes of rotation of support device 15 run parallel to the axis of rotation of the working roller or supported length-changing device 12. Second distance 11 is shown as the distance between second or lower working roller 3, 18 and rolling mill-side or lower joint 7, 17. The offset arrangement of the two rolling mill-side joints 6, 7 creates sufficient space so that rolling mill-side joints 6, 7 can protrude beyond pass line 21 without colliding with the other drive shaft.

COMPONENT IDENTIFICATION LISTING

• • 1 rolling mill assembly
  • 2 first working roller
  • 3 second working roller
  • 4 first cardan shaft
  • 5 second cardan shaft
  • 6 first rolling mill-side joint
  • 7 second rolling mill-side joint
  • 8 first drive-side joint
  • 9 second drive-side joint
  • 10 first distance
  • 11 second distance
  • 12 device for changing length
  • 13 first drive device
  • 14 second drive device
  • 15 support device
  • 16 lower cardan shaft
  • 17 lower rolling mill-side joint
  • 18 lower working roller
  • 19 shaft body
  • 20 hub
  • 21 pass line
  • g gravity
  • D_G joint diameter
  • D_W roller diameter

While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

Claims

1. A rolling mill assembly, comprising: a first working roller;a second working roller;a first cardan shaft;a second cardan shaft;a first drive device; anda second drive device, the first working roller being connected to the first cardan shaft, which in turn is connected to the first drive device, the first cardan shaft including a first rolling mill-side joint and a first drive-side joint, the second working roller being connected to the second cardan shaft, which in turn is connected to the second drive device, the second cardan shaft including a second rolling mill-side joint and a second drive-side joint, the first rolling mill-side joint being located at a first distance to the first working roller, the second rolling mill-side joint being located at a second distance to the second working roller, the first distance and the second distance differing by 0.5 m to 4 m, the first cardan shaft further including a first device configured for length change between the first rolling mill-side joint and the first drive-side joint, the second cardan shaft further including a second device configured for length change between the second rolling mill-side joint and the second working roller.

2. The rolling mill assembly according to claim 1, wherein the second cardan shaft is a lower cardan shaft, the second rolling mill-side joint being a lower rolling mill-side joint, the second working roller being a lower working roller, the second device configured for length change being a lower device configured for length change.

3. The rolling mill assembly according to claim 1, further including a support device, wherein at least one of the first device configured for length change and the second device configured for length change is supported by way of the support device.

4. The rolling mill assembly according to claim 1, wherein the first cardan shaft does not have a device configured for length change between the first rolling mill-side joint and the first working roller.

5. The rolling mill assembly according to claim 1, wherein at least one of: (a) the first rolling mill-side joint has a diameter that is 3% to 30% larger than a diameter of the first working roller which is connected thereto; and(b) the second rolling mill-side joint has a diameter that is 3% to 30% larger than a diameter of the second working roller which is connected thereto.

6. The rolling mill assembly according to claim 1, wherein the first rolling mill-side joint has a diameter that is within a range of 40 cm to 150 cm, wherein the second rolling mill-side joint has a diameter that is within a range of 40 cm to 150 cm, wherein the first cardan shaft is configured for transmitting a torque of 200 knm to 15.000 knm, and wherein the second cardan shaft is configured for transmitting a torque of 200 knm to 15.000 knm.

7. The rolling mill assembly according to claim 1, wherein at least one of: (a) the rolling mill assembly further includes at least one first support device, wherein the first cardan shaft is supported by way of the at least one first support device; and(b) the rolling mill assembly further includes at least one second support device, wherein the second cardan shaft is supported by way of the at least one second support device.

8. The rolling mill assembly according to claim 1, wherein at least one of: (a) the first device configured for length change includes a first inner shaft body and a first outer hub, wherein the first inner shaft body includes a first plurality of splines, and the first outer hub includes a first plurality of mating splines configured for mating with the first plurality of spines; and(b) the second device configured for length change includes a second inner shaft body and a second outer hub, wherein the second inner shaft body includes a second plurality of splines, and the second outer hub includes a second plurality of mating splines configured for mating with the second plurality of spines.

9. The rolling mill assembly according to claim 1, wherein the first cardan shaft includes a first plurality of cross joints, and the second cardan shaft includes a second plurality of cross joints.

10. The rolling mill assembly according to claim 1, wherein the first cardan shaft includes a first plurality of trunnion joints or a first plurality of gear coupling joints, and the second cardan shaft includes a second plurality of trunnion joints or a second plurality of gear coupling joints.