EP4025359B1 - Cross-rolling unit and method for setting the roll pass of a cross-rolling unit - Google Patents

Description

The invention relates to a cross-rolling unit and a method for adjusting the rolling caliber of a cross-rolling unit.

Such cross rolling units or adjustment processes are known, for example, from EP 2 116 312 A1 known. The cross rolling unit comprises at least two rolls, each mounted in a rolling mill, a rolling stand in which at least one of the rolling mills is mounted so as to be adjustable in its position via a rolling mill adjustment, an eccentric bush, to change the rolling caliber, in this case the feed. JP53-149858
reveals a corresponding cross-rolling unit. The EN 10 2016 219 723 A1 discloses a corresponding cross-rolling unit with pressure stilts for adjusting the rolling caliber.

It is the object of the present invention to provide cross-rolling units and methods for adjusting the rolling caliber of cross-rolling units which enable the best possible rolling result to be achieved.

The object of the invention is achieved by cross-rolling units and methods for adjusting the rolling caliber of cross-rolling units with the features of the independent claims. Further, possibly also independent of these, advantageous embodiments can be found in the subclaims and in the following description.

The invention is based on the basic finding that a good rolling result can be achieved if the rolling caliber can be adjusted during rolling. This allows the rolling caliber to be adapted to changing rolling parameters, which can be obtained, for example, through suitable measurements.

The cross-rolling unit comprises at least two rolls and a roll stand in which at least one of the rolls is mounted so that it can be adjusted in position to change the roll caliber. This allows the rolls to be adjusted to a specific roll caliber.

In particular, both or, if more rollers and associated roller mills are used, all of the roller mills of the two rollers can be mounted so as to be adjustable in their position above a roller mill adjustment in order to change the roller caliber, which enables a more precise adjustment or alignment of the roller caliber.

In order to provide cross-rolling units that achieve the best possible rolling result, in implementation of the above-mentioned basic knowledge, a cross-rolling unit with at least two rolls and with a roll stand in which at least one of the rolls is mounted so as to be adjustable in its position in order to change the roll caliber can be characterized in that a roll positioning device comprises a part bound to the stand and a part bound to the roll frame that can be moved thereto during rolling, which are adjustable relative to one another and that a drive of the roll positioning device is such that
is dimensioned to be able to apply rolling forces, wherein the roll positioning device comprises at least one hydraulic cylinder and is variable in its position during rolling, wherein the roll positioning device comprises at least one movable hydraulic cylinder operable with more than 50,000 hPa and
the hydraulic cylinder can be controlled with quick-acting valves of the cross-rolling unit. Preferably, the at least one hydraulic cylinder can be moved at over 30 mm/s.

The first part of the roller positioning device is preferably firmly connected to the stand and the second part is connected to the rolling mill. The stand and thus also the first part of the roller positioning device remain stationary in the same place during rolling or can also rotate in a constant path during rolling if necessary. The rolling mill and accordingly also the second part of the roller positioning device connected to it are adjustable relative to the first part or the roller stand, with the stand preferably remaining in its position if necessary also in its rotating path and the rolling mill adjusting accordingly. The adjustment can take place in particular during rolling, with the parts of the roller positioning device also being able to adjust under load. The rolling caliber can thus be adjusted during rolling, for example in order to produce a changing diameter on the workpiece or in order to be able to react accordingly to geometry changes on the workpiece or to rolling parameters that change during rolling, for example when running in or running out. For example, if the eccentricity of the workpiece is not constant, the rolling caliber could be individually adapted to the shape of the rolling piece during rolling.

Furthermore, in order to provide cross-rolling units that allow the best possible rolling result to be achieved, a cross-rolling unit with at least two rolls and with a roll stand in which at least one of the rolls is mounted so as to be adjustable in its position in order to change the roll caliber can be characterized in that a drive of the roll positioning device is dimensioned in such a way as to be able to apply rolling forces.

If the roll positioning device is dimensioned in such a way that it can apply the rolling forces, its position can also be changed during rolling and thus at least one of the rolls can be positioned differently, which in turn enables the roll caliber to be changed during rolling.

Cumulatively or alternatively, in order to provide cross-rolling units that achieve the best possible rolling result, a cross-rolling unit with at least two rollers and with a roller stand in which at least one of the rollers is mounted so that it can be adjusted in position to change the rolling caliber, can be characterized in that the mandrel position of a mandrel can be adjusted parallel to the workpiece during rolling by means of a mandrel position adjustment device. This also means, with suitable concrete implementation, that the rolling caliber can be adjusted or adapted during rolling in accordance with the basic knowledge explained above.

This means, for example, that the position of the mandrel in relation to the rollers can be changed, thus influencing the influence of the rolling forces on the workpiece or on the mandrel and therefore the rolling caliber. For example, the mandrel can be adjusted at the same speed as the workpiece during rolling, meaning that the workpiece is only pierced to the point where the mandrel did not move at the same speed and direction as the workpiece. The mandrel can also be removed more easily from the workpiece if the workpiece is not completely pierced or after rolling. The advantages mentioned above can be promoted in particular by the adjustability of a mandrel during rolling using a mandrel position adjustment device parallel to the workpiece.

But the spread angle or similar, and therefore also the roll caliber, can also be changed via the mandrel position adjustment device by adjusting the mandrel position adjustment device, for example if it is arranged as a mandrel holder along the roll axis at a distance from the rolls, perpendicular to the roll axis, which, as already indicated above, can also be done by appropriately adjusting or setting the rolls. The former, however, enables the roll caliber to be changed independently of the direction of movement of the roll mill or the part of the roll positioning device attached to the roll mill or independently of the direction of movement of the roll positioning device itself, so that adjustment options for the roll caliber can be provided more cost-effectively here if necessary.

In particular, it is advantageous if the roller positioning device comprises at least one hydraulic cylinder, which enables a sufficiently dynamic and, in particular, with a suitable design, rapid adjustment of the respective roller.

It is particularly advantageous here to use a hydraulic cylinder with which high pressures can be used and with which high travel speeds are likely to be possible. This then makes it possible in particular to have the respective hydraulic cylinder bear at least part of the rolling forces or to change the rolling caliber during rolling. Since the corresponding hydraulic cylinder can be operated at more than 50,000 hPa, rolling forces can then be applied by the roller positioning device. Particularly fast adjustment options can be ensured if the hydraulic cylinder can be moved at more than 30 mm/s, preferably at more than 35 mm/s, and can be controlled with quick-acting valves.

Depending on the specific implementation, it may be sufficient if the lifting height of the hydraulic cylinder is less than 150 mm. Depending on the specific implementation, even lifting heights of less than 100 mm can lead to satisfactory results. If necessary, a two-stage system can be provided in which the rolling caliber is preselected with a coarse roller positioning device, while an adjustment can then be made during rolling using a finer roller positioning device, for example with a low stroke, high adjustment speed and/or high pressures.

Preferably, two or even more roller positioning devices are provided for at least one of the rollers, possibly even for several or all of the rollers. This enables the corresponding rollers to be positioned more precisely, possibly even in terms of their angle. The rolling forces can then also be distributed across several roller positioning devices, so that they can be counteracted in a structurally simpler manner.

It is advantageous if the cross-rolling unit comprises a multi-variable control system which comprises at least two input variables and at least one output variable, both of which can be determined by the roller positioning device or are transmitted to the roller positioning device. The input variables can be made up of measured variables which are determined, for example, by the roller positioning device or by other measuring systems and transmitted to them. This allows control processes to be carried out based on the measured data so that the cross-rolling unit or an associated control system can intervene in the rolling process accordingly.

The measured values determined by the roller positioning device are available to the cross rolling unit in a relatively simple way. The rolling force in particular, but also the position of the rollers or the rolling mills, are suitable measured values.

In particular, the input variables can be cumulatively or alternatively the measured variables workpiece entry speed, workpiece exit speed, wall thickness,
Eccentricity, outside diameter, ovality, rolling force and mandrel holding force are recorded, which are then used cumulatively or alternatively for multi-variable control.

In this respect, a multi-variable control system that includes at least two input variables and at least one output variable is advantageous, as this allows the rolling process to be monitored more precisely and reacted to accordingly. It goes without saying that this advantage can be further enhanced by additional input or output variables. On the other hand, it is also conceivable that only one input variable and/or only one output variable are used if this appears sufficient for the specific application.

The workpiece infeed speed describes the speed of the workpiece relative to the rolls before rolling. Depending on the workpiece infeed speed, the required or advantageous rolling caliber can also change. The dimensions of the workpiece can also be decisive for which workpiece infeed speeds are possible, for example. In addition, this speed can be a required variable to be regulated if the mandrel is to be adjusted in a certain speed ratio to the workpiece. It goes without saying that, since blocks or hollow blocks can be used as workpieces, which then pass through the cross-rolling unit with or without holes, the infeed speed of the blocks or hollow blocks can serve as a measurement variable.

The workpiece run-out speed, on the other hand, describes the speed of the workpiece relative to the rollers after rolling, after piercing or when the workpiece is being moved out or run out. The hollow block run-out speed is often higher than the block run-in speed, since rolling often shifts material in the direction of the workpiece's movement. This is particularly true for expansion processes, when However, in punching or other rolling processes, the workpiece exit speed can also be higher than the workpiece entry speed.

If necessary, the difference between the workpiece entry and exit speed can also be used advantageously as a measured value or as a value derived from it, since this value can also provide important information about the rolling process under certain circumstances.

Particularly in the case of cross rolling, the rotational speed of the workpiece, possibly differentiated on the input side and/or output side, can also serve as a measurement variable, since information about the rolling process can also be obtained from this.

The position of the workpiece, such as the length of the workpiece that has already been rolled or the length of the workpiece that is not to be rolled, can also be a suitable measurement variable for optimizing the rolling process in a targeted manner. This means that, for example, different control variable values or a different weighting of measurement variables can be provided when determining the control variables at the start or end of rolling.

The wall thickness describes the difference between the outside diameter and the inside diameter of the workpiece, especially of a perforated block or a hollow block. The required or measured wall thickness can serve as a measurement value cumulatively or alternatively.

Eccentricity describes the deviation of an ellipse from a circular shape. This measurement may be necessary for preventive control in order to be able to determine the eccentricity of the workpiece before rolling and to react accordingly. For example, rolling can be controlled in such a way that, despite the eccentricity of the workpiece, the rolling process or, in particular, other control or output variables are adjusted in such a way that the desired rolling result can be achieved or that the eccentricity can be optimized, for example, by suitable process engineering measures and geometric irregularities can be corrected. Eccentricity can also be a subsequent control criterion to check whether rolling has changed the eccentricity of the workpiece. Eccentricity can be important both on the outside diameter and on the inside diameter.

The outside diameter describes the external diameter of the workpiece. By referring to the wall thickness, the inside diameter of the workpiece, in particular a pipe, can also be determined and used as an input variable.

The ovality of the workpiece describes the difference between the largest and smallest outside diameter in one plane. This can be helpful in determining whether process-related adjustments to the control variables are necessary in order to achieve the best possible rolling result. On the other hand, the ovality can be used as a subsequent
Control can be used, for example, to check tolerances or to check to what extent rolling has influenced the dimensions of the workpiece.

The rolling force describes the force that the workpiece experiences during rolling or the force that the rollers apply to the workpiece during rolling. The rolling force can vary depending on the dimensions and properties of the workpiece. However, the rolling force must be applied throughout the entire rolling process to ensure reliable rolling.

The mandrel holding force describes the force with which the mandrel acts on the workpiece, particularly during rolling, and corresponds to the force with which the mandrel must be held during rolling. The size of the mandrel holding force can depend in particular on the nature of the workpiece and the workpiece entry speed. This force can also vary accordingly when adjusting the mandrel position or the spreading angle.

The output variables preferably comprise control variables which are adjusted, for example, to regulate the rolling caliber, in particular during rolling.

The control variables can in particular include a dynamic positioning adjustment of at least one of the rollers, an adjustment of the rolling center by adjusting all the rollers, a dynamic adjustment of the mandrel position and/or an adjustment of the spreading angle. The control variables are used for multi-variable control in that the control variables can be used to react to the input variables or to control the input variables accordingly. The control variables all describe adjustment options for the individual elements of the cross-rolling unit, such as the adjustment of the rollers and the mandrel. These adjustment options, which are determined by the control variables, are used to actively influence the measured variables. For example, a certain rolling force can only be determined by adjusting the position of the upper or lower roller accordingly.

However, the rotational speed of the rollers or the rotary drive force acting on the rollers and similar can also be used cumulatively or alternatively as output variables.

In order to provide methods for adjusting the rolling caliber of cross-rolling units that allow the best possible rolling result to be achieved, the methods for adjusting the rolling caliber of a cross-rolling unit with at least two rolls can be characterized in that at least one of the rolls is adjusted during rolling. It goes without saying that two or all of the rolls of the cross-rolling units can also be adjusted accordingly. This also cumulatively or alternatively implements the basic insight explained at the beginning that adjustment of the rolling caliber should be possible during rolling.

Cumulatively or alternatively, a method for adjusting the rolling caliber of a cross-rolling unit with at least two rolls can be characterized in that a spreading angle or setting angle and/or the axial position of a mandrel are adjusted during rolling in order to achieve the best possible rolling result. The rolling caliber can also be adapted to any changes or abnormalities in the respective specific rolling process by moving the mandrel, be it in its spreading angle or setting angle or in its axial position in relation to the rolls.

It should be noted at this point that the axial position of the mandrel is usually defined in relation to the rolling centre line or in relation to the line of passage of the workpieces through the respective cross-rolling unit and then the relative position of the mandrel on the rolling centre line or on the line of passage in relation to the rolls is determined.
This axial position can be determined and adjusted as required, in particular, by a mandrel holder, by a mandrel rod holder or by a mandrel position adjustment device holding the mandrel.

Preferably, the spreading angle or angle of attack of the mandrel can be adjusted, which determines the angle between the mandrel and the workpiece. This changes the shape or the area of the mandrel head, which comes into contact with the workpiece immediately when the workpiece is punched or rolled and thus determines the position that occurs during rolling. This can change the rolling forces or speed of the workpiece that may be required. The adjustable spreading angle allows, for example, ovality, eccentricity or the general shape of the hole to be changed or optimized as required.

It is advantageous if a single roll is set to a specific roll caliber relative to the second fixed roll or is adjusted during rolling to provide a specific roll caliber. In this case, the effort required to adjust the Rolling calibers should be kept as low as possible, since only one roll needs to be driven, adjusted or set. Depending on the measured values determined and other requirements, this may already be sufficient to achieve good rolling results.

It is also conceivable that at least two corresponding rollers are set to a certain rolling caliber or adjusted during rolling. Because the total rolling force to be applied is not applied by the drive of one roller, but by at least two drives of the two rollers, each drive of the rollers applies less force than when adjusting with one roller. For example, when adjusting two rollers, half the force required when adjusting one roller can be applied.
be.

Advantageously, when adjusting at least two corresponding rolls, the corresponding rolls are adjusted synchronously with a certain roll caliber or adjusted synchronously during rolling. When adjusting the corresponding rolls synchronously, the roll center line may shift, but this may also
may be desired. Depending on the specific design of a roller positioning, this can also be prevented by moving the rollers exactly against each other or only changing their angle of inclination. This is very advantageous for the entire device, as the workpiece can also be moved further along its line. When moving the roller center line, rolling with straight-line transport of the workpiece can be achieved if necessary.
operational safety can no longer be guaranteed.

With a suitable design, a more precise roll caliber adjustment or roll caliber setting can also be provided by adjusting or setting at least two corresponding rolls than by adjusting or setting one roll.

In order to ensure a reliable and error-free rolling process, rolling forces can be applied continuously by driving the roller mill positioning device. This makes it possible to move or adjust the rollers even during rolling, as the risk of jamming or similar problems can be minimized.

Depending on the specific design, a roller mill can be mounted so that it can be adjusted using several or only one roller positioning device. If there are several roller positioning devices for a roller mill, the roller positioning devices can be used to adjust the roller positioning devices. For example, targeted angle changes of the rollers can be made using the roller positioning devices. On the other hand, adjusting a roller mill using only one roller positioning device enables a simpler structure, which can be particularly advantageous for roller mills that support both sides of the rollers.

Preferably, the adjustment of the roller, the rollers or the mandrel takes place as a function of determined measured variables, such as those already mentioned above, in particular not merely according to a previously determined rolling plan which depends only on the position of the workpiece or on the time.

As a rule, the rolling center line is a theoretically and mechanically specified ideal line on which the rolling stock passes through the cross-rolling unit. In this context, it should be emphasized again that cross-rolling or cross-rolling units are distinguished from longitudinal rolling or longitudinal rolling units by the fact that the axes of the two rolls have a component parallel to a rolling center line of the cross-rolling unit or the cross-rolls. In cross-rolling units or cross-rolling, the rolling surface of the rolls has a rotation component perpendicular to the rolling center line of the cross-rolling unit or the cross-rolls during rolling, which represents a different distinction from longitudinal rolling, in which the roll surface is moved parallel to the rolling center line or parallel to the direction of movement of the material. This means that the exact roll position is much more difficult and complex for a
specific rolling process than with longitudinal rolling. The position of the rolls in cross rolling also generally has a much more complex influence on the rolling process. In particular, the corresponding rolling mills and their connection to the roll stand are very complex.

In this context, the rolling caliber describes in particular the free space that the cross-rolling unit leaves for the workpiece during rolling. It therefore includes in particular the position of the rollers and, if present, the mandrel. However, particularly in connection with cross-rolling units, it also describes the position of the roller surface in relation to the workpieces in terms of its angle in relation to the rolling center line.

It is understood that the features of the solutions described above or in the claims can also be combined if necessary in order to be able to implement the advantages cumulatively.

Figur 1

eine schematische Aufsicht auf zwei Schrägwalzen eines Schrägwalzaggregats;

Figur 2

eine schematische Seitenansicht eines ersten Schrägwalzaggregats;

Figur 3

eine schematische Seitenansicht eines zweiten Schrägwalzaggregats;

Figur 4

eine schematische Frontansicht eines dritten Schrägwalzaggregats;

Figur 5

eine schematische Seitenansicht des dritten Schrägwalzaggregats;

Figur 6

eine schematische Frontansicht eines vierten Schrägwalzaggregats;

Figur 7

eine schematische Seitenansicht des vierten Schrägwalzaggregats;

Figur 8

eine schematische Seitenansicht eines durch ein Schrägwalzaggregat mit Dorn laufenden Werkstücks mit Mess- und Stellgrößen; und

Figur 9

eine schematische Darstellung der Mehrgrößenregelung mit Ein- und Ausgangsgrößen.

Further advantages, objectives and properties of the present invention are explained in the following description of embodiments, which are also shown in particular in the attached drawing. In the drawing:

Figure 1

a schematic plan view of two cross rolls of a cross rolling unit;

Figure 2

a schematic side view of a first cross-rolling unit;

Figure 3

a schematic side view of a second cross rolling unit;

Figure 4

a schematic front view of a third cross rolling unit;

Figure 5

a schematic side view of the third cross rolling unit;

Figure 6

a schematic front view of a fourth cross rolling unit;

Figure 7

a schematic side view of the fourth cross rolling unit;

Figure 8

a schematic side view of a workpiece running through a cross rolling unit with mandrel with measuring and control variables; and

Figure 9

a schematic representation of the multi-variable control with input and output variables.

The cross-rolling units 10 shown in the figures each comprise at least two rolls 20 (see Figures 1 to 3 ) or three reels 20 (see Figures 4 to 7 ), which are carried in roller mills 21, which in turn are mounted on a roller stand 27 so as to be adjustable via a roller positioning device 22.

The rollers 20 can rotate about roller axes 25 and have rolling surfaces 26 which are successively coated with a Figure 8 come into contact with the elongated workpiece 32 shown in more detail.

In this case, the workpiece 32 essentially runs along a rolling center line 11, which roughly represents the center of gravity of the material passing through and - more precisely - represents the axis from an inlet roller table (not shown) through the center of the rolling unit to an outlet roller table (not shown).

The roller axes 25 are aligned essentially parallel to the roller center line 11, whereby in the present embodiment a slight inclination angle of between 5° and 8° is provided. In different embodiments, other inclination angles can of course also be used, if necessary also with respect to the horizontal.
be provided.

The rollers 20 themselves have a relatively complex rolling surface 26, which in turn leads to a relatively complex rolling caliber and in particular, this also leads to a different load on the respective roller mills 21 of a roller 20. This means that the roller axes 25 can also be inclined relative to the horizontal, which can possibly be provided for in the case of cross-rolling units 10 even without a load.

The roller positioning device 22 of the Figures 1 and 2 The embodiments shown are connected to the roller stand 27 via longitudinal beams which serve as attack points 24, so that the rolling forces are guided into the roller stand 27 via the attack points 24 or via the connection between the attack points 24 and the roller stand 27, which can be referred to as attack 23, which leads to a corresponding springing of the roller stand 27, which can ultimately lead to a corresponding non-uniform loading of the roller stand 27 in accordance with the non-uniform loading of the rollers 20 and the roller mills 21 already indicated above.

In the Figures 4 to 7 In the embodiments shown, a solid roller stand 27 is provided, in which in the embodiment according to Figures 4 and 5 a thread to a roller positioning device 22 and in the embodiment according to Figures 6 and 7 a hydraulic cylinder and piston arrangement are introduced, which can be used to adjust the rollers 20 and defined as an attack 23. It is understood that in different embodiments, if necessary, also in the embodiment according to Figures 6 and 7 Threads can be provided as roller positioning devices, while in the Figures 4 and 5 In the embodiment shown, hydraulic roller positioning devices 22 can also be used instead of the threads.

In the case of the arrangements according to Figures 2 to 5 Each roller mill 21 is mounted on the roller stand 27 so that it can be adjusted by two roller positioning devices 22. This allows the roller axes 25 in particular to be adjusted at an angle to the roller center line 11 or non-uniform load changes to be counteracted.

The examples according to Figures 6 and 7 In contrast, each roller mill 21 has only one roller positioning device 22, which is structurally simpler to implement.

It is understood that even in the embodiments according to Figures 2 to 5 only one roller positioning device and/or one hydraulic roller positioning device 22 can be provided, while in the embodiment according to Figures 6 and 7 if necessary, two roller positioning devices 22 or mechanical roller positioning devices 22 can be provided. Mechanical and hydraulic roller positioning device 22 may be combined if necessary. Other roller positioning devices 22, such as piezoelectric or pneumatic adjustments, may also be provided.

As can be seen directly from the figures, the rolling surface 26 of the rollers 20 has a movement component perpendicular to the rolling center line 11 of the cross-rolling unit 10 during rolling. As a rule, this accordingly means that the rolling surface 26 of the rollers 20 has a movement component perpendicular to the direction of movement of the workpiece 32 through the cross-rolling unit 10 during rolling. The axes 25 of the two rollers 20 also have a component parallel to the rolling center line 11 of the cross-rolling unit 10, as can be seen directly from the figures.

In the Figure 2 In the embodiment shown, the path 40 between the two roller mills 21 of both rollers 20 is measured by arranging a path measuring system 41 between roller covers 50 on the roller mills 21 and reference covers 60 arranged on the respective roller mill 21, whereby the measurement can also be carried out without further ado
during rolling. In this case, the roller cover 50 of a first roller mill 21 can be specifically referred to as the reference reference 60 of the second roller mill 21 using the same position measuring system 41.

It is understood that in a different embodiment, only a single position measuring system 41 can be used, which can then only be used between two roller mills 21 or covers 50, 60, each of which is provided on one of the two rollers 20, which, however, can then only make a somewhat less precise statement about the respective roller caliber.

In this embodiment, the respective ends of the path measuring system 41 are attached directly to the roller mills 21, so that the roller mills 21 themselves serve as roller reference points 51 or reference reference points 61. Accordingly, the roller mills 21 also serve as the respective reference for measuring the path 40 to the other roller mill 21.

It is understood that in the embodiment according to Figure 2 if necessary, separate assemblies can also serve as roller reference points 51 or reference reference points 61, as is the case in the embodiment according to Figure 3 is shown as an example. Other assemblies, such as between the roller positioning devices 22 and the assemblies provided for the roller mills 21 or the longitudinal or column beams are used accordingly or corresponding separate assemblies serve as supports for the roller reference points 51 or reference reference points 61.

In the Figure 3 In the embodiment shown, projections are provided as roller reference point 51 and reference reference point 61, respectively, wherein the projections for the roller reference point 51 are arranged on the roller mills 21 and the projections for the reference reference points 61 are arranged on a separate reference frame 62.

The reference frame 62 is decoupled from the roll stand 27 so that it provides a reference or reference reference 61 independently of the respective rolling forces. The latter is also the case in the embodiment according to Figures 4 and 5 the case, whereby the roller reference points 51 or the roller covers 50 are provided on the roller frames 21, which, however, can also be provided on other assemblies in different embodiments, as is the case in the embodiment according to Figures 6 and 7 which also uses a reference frame 62.

It is understood that in a different embodiment of the Figures 3 , 6 and 7 illustrated embodiments, separate approaches for providing the roller reference points 51 or the reference reference points 61 can also be dispensed with if this is structurally feasible, in particular with regard to space, where appropriate, the oblique arrangement of the rollers 20 with the resulting offset arrangement of the roller mills
21 can be used to couple the position measuring system 41 without separate attachments.

Also, in the Figures 3 to 7 In the embodiments shown, a distance measurement between the rollers 20 or the roller mills 21 can be carried out, as is exemplified by the example in Figure 2 illustrated embodiment.

In the Figure 3 In the embodiment shown, only one roller mill 21 of each roller 20 is recorded in its path 40, whereby it is understood that, as shown in crossed-out lines, a further reference frame 62 can also be provided for measuring the other roller mills 21 of each roller 20 in order to be able to make even more precise statements about the rolling caliber. Likewise, in the embodiments according to Figures 4 to 7 Individual position measuring systems 41 may be dispensed with without sacrificing the corresponding measurement accuracy.

As is immediately apparent, the embodiments according to Figure 3 to 7 the path 40 between the roller frames of the rollers 20 and a reference provided outside the attack 23 is measured. For this purpose, the reference reference 61 is arranged outside the attack point 24 of the roller positioning device 22 of the roller frame 21 engaging the roller stand 27.

In the present embodiments, resistance sensors, capacitive sensors and/or inductive sensors are used as distance measuring systems 41 or for distance measurement. Alternatively, optical distance meters, ultrasonic sensors or radar sensors can also be used accordingly.

Accordingly, a contact or non-contact measurement can be carried out.

In the Figure 8 The embodiment shown schematically illustrates a piercing process of a workpiece 32 by means of a mandrel 30 and two rollers 20. A corresponding procedure can be used in particular in conjunction with the other cross-rolling units 20 presented here.

It is understood that hollow blocks can alternatively be rolled with a mandrel 30 as an internal tool with corresponding cross-rolling units 10. Internal tools or mandrels 30 can also be dispensed with if necessary, regardless of whether a block or a hollow block is cross-rolled as a workpiece 32.

Also in Figures 8 and 9 Examples of control and measurement variables are shown which can be used advantageously for a multi-variable control 70 among other control and measurement variables as input variables or as output variables in all embodiments shown here. It is understood that if necessary, only individual measurement and control variables can be used and individual ones of these measurement and control variables can be dispensed with or other measurement and control variables and variables derived therefrom can be used for the multi-variable control 70.

For example, the workpiece entry speed 71, the workpiece exit speed 72, the wall thickness 73, the eccentricity 74, the outside diameter 75, the ovality 76, the rolling force 77 and the mandrel holding force 78 can serve as measurement variables and are in the Figure 8 shown schematically. These measurements and other measurements as well as the Quantities derived from measured variables can then serve as input variables of the multi-variable control 70, as shown in Figure 9 shown as an example.

Also in the Figures 8 and 9 By way of example, an adjustment 80 of the spreading angle, a dynamic positioning adjustment 81 of the rollers 20 used here as upper and lower rollers, a dynamic adjustment 82 of the roller center by synchronously adjusting the rollers used as upper and lower rollers and the dynamic adjustment 83 of the mandrel position are schematically shown as control variables.

In concrete terms, these control variables can be implemented, if necessary, by individual output variables to the respective roller positioning devices 22 and a mandrel position adjustment device 31 holding the mandrel 30, while in the present embodiment these control variables each address the associated actuators, i.e. the roller positioning devices 22 and the mandrel position adjustment device 31, together in order to ensure, for example, a synchronous movement of the rollers 20.

It is understood that the adjustment 80 of the spreading angle can be achieved, for example, by a corresponding adjustment of the mandrel 30 with the mandrel position adjustment device 31 perpendicular to the roll center line 11 or by the dynamic adjustment 82 of the roll center.

The mandrel position adjustment device 31 can also adjust the axial position of the mandrel 30, i.e. its position in relation to the rollers 20 seen along the roller center line 11, which can also be used as a control variable if necessary.

All control variables shown in this embodiment can be adjusted, in particular during rolling.

List of reference symbols:

10

Cross rolling unit

11

Roll centerline

20

roller

21

Rolling mill

22

Roller positioning device

23

attack

24

Attack point

25

Roller axes

26

Roller surface

27

Roller stand

30

mandrel

31

Mandrel position adjustment device

32

workpiece

40

Path (shown as an example)

41

Position measuring system

50

Roller cover (exemplary numbered)

51

Roller reference point (exemplary numbered)

60

Reference (exemplary number)

61

Reference point (exemplary numbered)

62

Reference frame

70

Multi-variable control

71

Workpiece infeed speed

72

Workpiece run-out speed

73

Wall thickness

74

eccentricity

75

Outside diameter

76

Ovality

77

Rolling force

78

Mandrel holding force

80

Adjusting the spread angle

81

dynamic positioning adjustment individually

82

dynamic adjustment of the rolling center

83

dynamic adjustment of the mandrel position

Claims (16)

1. Cross-rolling unit (10) with at least two rolls (30) and with a roll housing (27) in which at least one of the rolls (30) is mounted to be adjustable in its position for changing the roll pass, characterised in that a roll positioning device (22) comprises a part connected with the housing and a part which is movable relative thereto during the rolling and is connected with a rolling mill (21), the parts being adjustable relative to one another, and that a drive of the roll positioning unit (22) is dimensioned in such a way as to be able to exert rolling forces, wherein the roll positioning device (22) comprises at least one hydraulic cylinder and is variable in its setting during the rolling, wherein the roll positioning device (22) comprises at least one movable hydraulic cylinder which is operable at more than 50,000 hPa and which is controllable by quick-action switching valves of the cross-rolling unit (10).
2. Cross-rolling unit (10) according to claim 1, characterised in that the mandrel position of a mandrel (30) is adjustable parallel to the workpiece by means of mandrel position adjusting device (31) during the rolling.
3. Cross-rolling unit (10) according to claim 1 or 2, characterised in that the stroke length of the at least one hydraulic cylinder lies under 150 mm, particularly under 100 mm.
4. Cross-rolling unit (10) according to any one of claims 1 to 3, characterised in that two roll positioning devices (22) are provided for at least one of the rolls (30).
5. Cross-rolling unit (10) according to any one of claims 1 to 4, characterised by a multi-variable regulation (70) which comprises at least input variables and at least one output variable.
6. Cross-rolling unit (10) according to any one of claims 1 to 5, characterised in that the input variables and the output variables are both determinable by the roll positioning device (22) and/or are transmitted to the roll positioning device (22) and/or that the input variables comprise the measured variables of workpiece entry speed (71), workpiece exit speed (72), wall thickness (73), eccentricity (74), outer diameter (75), ovality (76), rolling force (77) and/or mandrel holding force (78) and/or that the output variables comprise the setting variables of dynamic position adjustment (81) of at least one of the rolls (20), adjustment of the roll centre (82) by adjustment of all rolls (20), dynamic adjustment of the mandrel position (83) and/or adjustment of the spread angle (80) which determines the angle between mandrel (30) and workpiece.
7. Cross-rolling unit (10) according to any one of claims 1 to 6, characterised in that at least one hydraulic cylinder is movable at more than 30 mm/s.
8. Method for adjusting the roll pass of a cross-rolling unit (10) with at least two rolls (20), characterised in that at least one of the rolls (20) is adjusted during the rolling.
9. Roll pass adjusting method according to claim 8, characterised in that a spread angle (80) which determines the angle between mandrel (3) and workpiece is adjusted during the rolling.
10. Roll pass adjusting method according to claim 8 or 9, characterised in that the axial position of a mandrel (30) is adjusted during the rolling.
11. Roll pass adjusting method according to any one of claims 8 to 10, characterised in that a single roll (20) is set with a specific roll pass with respect to the second roll (20) of fixed location and/or is adjusted during the rolling.
12. Roll pass adjusting method according to any one of claims 8 to 11, characterised in that at least two corresponding rolls (20) are set with a specific roll pass.
13. Roll pass adjusting method according to any one of claims 8 to 12, characterised in that at least two corresponding rolls (20) are adjusted during the rolling.
14. Roll pass adjusting method according to claim 13, characterised in that at least two corresponding rolls (20) are synchronously set with a specific roll pass and/or synchronously adjusted during the rolling.
15. Roll pass adjusting method according to any one of claims 8 to 14, characterised in that constant rolling forces are exerted by the drive of the rolling mill positioning device (22).
16. Roll pass adjusting method according to any one of claims 8 to 14, characterised in that the adjustment of the rolls (20) and/or of the mandrel (30) is carried out in dependence on determined measurement variables.

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