CROSS-ROLLING MILL WITH HYDRAULIC ROLLER ACTUATOR

Abstract

A cross-rolling mill for rolling a block over a mandrel forms a hollow block. It includes a plurality of working rollers, each of which exerts a substantially radially aligned rolling force onto the block. The working rollers are supported in a roll stand, and the gap between the working rollers and preferably also the alignment of the rolling axis of at least one of the working rollers relative to the block can be modified. Hydraulic actuators, preferably hydraulic capsules, are provided in order to modify the rolling gap and preferably also the alignment of the rolling axis of at least one of the working rollers relative to the block.

Claims

1.-19. (canceled)

20. A cross-rolling mill for rolling a block over a mandrel so as to form a hollow block, comprising: a roll stand; a plurality of working rollers supported in the roll stand, each of which exerts a substantially radially aligned rolling force onto the block; and hydraulic actuators configured to modify a rolling gap between the plurality of working rollers.

21. The cross-rolling mill according to claim 20, wherein the hydraulic actuators are hydraulic capsules, and wherein the hydraulic capsules are configured to modify an alignment of a rolling axis of at least one of the plurality of working rollers relative to the block.

22. The cross-rolling mill according to claim 20, wherein the hydraulic actuators are capable of compensating for a roll stand expansion during rolling operation by modifying an adjustment of the working rollers relative to one another.

23. The cross-rolling mill according to claim 20, further comprising disks (so-called “Diescher disks”) and/or guide shoes which laterally limit the rolling gap and which are connected to hydraulic actuators.

24. The cross-rolling mill according to claim 20, further comprising a measuring device with which a modification in a rolling gap geometry and/or a rolling gap shift and/or a position of the working rollers in space along with their modification during rolling operation can be determined.

25. The cross-rolling mill according to claim 24, wherein the measuring device is connected to an evaluation unit which is suitable for determining disturbance variables.

26. The cross-rolling mill according to claim 20, further comprising a control and regulating unit which is connected to the hydraulic actuators in such a manner that previously determined modifications in a rolling gap geometry and/or a rolling gap shifting and/or a position of the working rollers in space along with their modification during rolling operation can be counteracted by modifying the rolling gap.

27. The cross-rolling mill according to claim 26, characterized in that the control and regulating unit is connected to an evaluation unit which is suitable for determining disturbance variables.

28. The cross-rolling mill according to claim 24, wherein the measuring device includes an optical image acquisition unit.

29. The cross-rolling mill according to claim 24, wherein the measuring device is capable of recording at least one image element connected to the roll stand and of determining a change in position and/or shape of the at least one image element.

30. The cross-rolling mill according to claim 29, wherein the at least one image element is an active luminous element.

31. The cross-rolling mill according to claim 29, wherein the at least one image element is circular with a defined diameter, or square or rectangular with known diagonal dimensions, or oval with a defined shape.

32. The cross-rolling mill according to claim 20, wherein a position of the mandrel can be modified within the rolling gap.

33. A method for producing a hollow block using a rolling process, comprising: providing a cross-rolling mill with a plurality of working rollers, each of which exerts a substantially radially aligned rolling force onto the block; supporting the plurality of working rollers in a roll stand such that a rolling gap between the plurality of working rollers can be modified by hydraulic actuators; rolling to block over a mandrel; and modifying the rolling gap during the rolling process.

34. The method according to claim 33, wherein modifying the rolling gap is effected if a change to a rolling gap geometry and/or a rolling gap shift and/or a position of the working rollers in space along with their changes during rolling operation, measured beforehand by a measuring device, have been determined by an evaluation unit and classified as disturbance variables.

35. The method according to claim 34, wherein a control and regulation unit is connected to the evaluation unit and outputs signals for compensating disturbance variables to the hydraulic actuators.

36. The method according to claim 34, wherein the measuring device comprises an optical image acquisition unit and is arranged at a distance from the roll stand.

37. The method according to claim 36, wherein the measuring device records an image element connected to the roll stand and determines its position and/or shape changes during the rolling process.

38. The method according to claim 34, wherein a position and/or alignment of the mandrel within the rolling gap is modified during the rolling process to compensate for previously determined disturbance variables.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 shows a schematic view of a part of a cross-rolling mill in accordance with a first embodiment.

[0027] FIG. 2 shows a schematic representation of a part of a cross-rolling mill in accordance with a second embodiment.

[0028] FIG. 3 shows a flow chart for the application of a method in accordance with the disclosure.

DETAILED DESCRIPTION

[0029] FIG. 1 shows in a first embodiment the mode of operation of a cross-rolling mill, comprising an upper working roller 1 and a lower working roller 2. The upper and lower working rollers 1, 2 are designed in the form of two truncated cones connected to each other at their large end faces and work together with a mandrel 5 arranged on a mandrel bar 4 during the forming of a block 3 in a direction from left to right (z-direction) in FIG. 1. Upon the suitable adjustment of the upper and lower working rollers 1, 2 relative to the block 3, the block 3 is conveyed from the entry side 6 to the exit side 7 by rotation of the upper and lower working rollers 1, 2 about their longitudinal axes 1a and 2a respectively through the rolling gap between the upper and lower working rollers 1, 2 and over the mandrel 5. At the respective ends of the upper and lower working rollers 1, 2, there are hydraulic actuators 8a, 8b, and 9a, 9b, by means of which the position of the working rollers 1, 2 relative to each other and in relation to the block 3 can be modified almost at will, in particular in the manner shown in a y-direction in a manner vertical to the rolling direction. By means of the vertical adjustment of the hydraulic actuators 8a, 8b, 9a, 9b, the rolling gap between the upper and lower working rollers 1, 2 can also be modified at least both in the y-direction and in the z-direction.

[0030] FIG. 2 shows an additional embodiment of an essential part of a rolling mill, comprising an upper working roller 1 along with a lower working roller 2, each of which shows a truncated cone shape with a discontinuous shell profile. Between the upper and lower working rollers 1, 2, there is in turn a rolling gap 10, into which the block 3 enters by movement in the direction z towards the mandrel 5 and is formed there into a hollow block (not shown) in cooperation of the upper and lower working rollers 1, 2 with the locally fixed piercing mandrel 5. At both ends of the upper and lower working rollers 1, 2, there are hydraulic actuators 8a, 8b and 9a, 9b respectively, by means of which a modification to the rolling gap 10 and the local position of the rolling axes 1a, 1b can be effected.

[0031] FIG. 3 shows a schematic flowchart of the method for producing a hollow block by means of a cross-rolling mill 11, which carries an upper working roller 1 and a lower working roller 2. Image elements MM1 and MM2 are arranged on roll housings of the roll stand 11 and are permanently monitored during the rolling operation with high accuracy and dynamically, both with regard to their position and their shape by a camera arranged at a distance, which is not shown in the picture. Each modification to position in the x-direction and the y-direction Dx1(t), Δy1(t) for the upper working roller 1 and Dx2(t), Δy2(t) for the lower working roller 2 is recorded by the measuring unit (not shown) and transmitted to an evaluation unit (also not shown). In such evaluation unit, it is determined whether the positional modifications to the image elements MM1, MM2 recorded by the image unit (not shown) are to be considered as control variables to be compensated for. If this is the case, the disturbance variables determined by the evaluation unit are forwarded to the HGC regulator as a control and regulation unit (hydraulic gap control regulator). Further process parameters are entered into the control and regulation unit (HGC), such that control commands Y1, Y2 are issued to the hydraulic actuators 8, 9 on the basis of previously defined algorithms. By adjusting the upper working roller 1 and/or the lower working roller 2 relative to the mandrel (not shown), such hydraulic actuators 8, 9 modify the rolling gap geometry and, if necessary, the alignment of the rolling axes (not shown) relative to each other. This makes it possible to output control and regulation commands online during the rolling process in a highly dynamic manner with constant acquisition and evaluation of measurement data, which commands are able to positively influence the rolling result and the course of the cross-rolling process.

LIST OF REFERENCE SIGNS

[0032] 1 Working roller [0033] 1a, b Rolling axis [0034] 2 Working roller [0035] 2a, b Rolling axis [0036] 3 Block [0037] 5 Mandrel [0038] 8 Actuator [0039] 8a, 8b Actuator [0040] 9 Actuator [0041] 9a, 9b Actuator [0042] 10 Rolling gap [0043] 11 Cross-rolling mill [0044] HGC Hydraulic gap control [0045] MM1 Image element [0046] MM2 Image element