DE20005697U1 - Rolling mill for rolling metallic pipes, bars or wires - Google Patents

Description

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Rolling mill for rolling metal tubes, bars or wires

Description:

The invention relates to a rolling mill for rolling metal tubes, bars or wires. ■

A rolling mill of this type is known from WO 98/06515, which has several rolling stands arranged closely one behind the other in a straight line, which can be replaced and each of which has three rollers surrounding a rolling axis in a star shape. Only a few, namely only the two last rolling stands on the outlet side, have rollers that are each driven by their own drive shaft. The other rolling stands, a much larger number, each have only one drive shaft, which then directly drives the roller shaft of the roller whose axis of rotation extends horizontally. The torque of the drive shaft is transmitted to the other two roller shafts by means of bevel gears that are arranged on all roller shafts. In order to ensure that the bevel gears remain in mesh with one another, no significant radial adjustment of the roller shafts and thus of the rollers is provided for in these rolling stands. However, in the two last rolling stands on the outlet side, the rollers can be adjusted in the radial direction, since they are individually driven and mounted so that they can move radially.

This known rolling mill has the major disadvantage that the vast majority of rolling stands, namely those with only one drive shaft, cannot be loaded sufficiently. The reason for this is that the roller bearings for absorbing the forces and the bevel gears for transmitting the torque must be arranged within an equilateral triangle formed by the axes of rotation of the rollers. This limits the external dimensions of the roller bearings and the bevel gears and consequently also the size of the rolling forces that can be absorbed and the transferable torque.

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torque. Increasing the triangle of the rotation axes would lead to larger rolls. However, larger rolls increase the distance between the rolling stands, which leads to an increase in the proportion of unusable end sections of the rolled stock that are not dimensionally accurate. In addition, larger rolls are more expensive to purchase and process. Furthermore, larger rolls result in higher investment costs for the entire rolling mill. Thus, enlarging the triangle of the rotation axes is not a solution to the problem.

In addition to their insufficient load-bearing capacity, the rolling stands with only one drive shaft have the disadvantage that the design inside the rolling stand housing is particularly complex because, in addition to the roller bearings, the bevel gears also have to be accommodated within the triangles of the rotation axes. Radial adjustment of the rollers is possible, but can only be achieved with even greater design effort. The high design effort, even without roller adjustment, leads to many individual parts and thus to high manufacturing and operating costs.

The complex design inside the roll stand housing has the additional disadvantage that changing the rolls is complicated and time-consuming. To do this, the roll stand housing must be opened and the roll bearings and bevel gears partially dismantled. After the rolls have been changed, a corresponding amount of assembly work is then required. In order to save assembly work and time, the rolls are reworked while installed, which then requires additional special machines.

In the known rolling mill, the vast majority of the rolling stands only have one drive shaft each, and the rolling mill therefore has all the disadvantages of these rolling stands. The rolling mill is therefore not sufficiently resilient, has complex and therefore expensive rolling stands, and requires a lot of effort when changing and reworking the rolls.

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In order to avoid further disadvantages, the known rolling mill does not have the radial adjustability of the rolls in the rolling stands with only one drive shaft, which is the case in the vast majority of rolling stands. However, this leads to significantly higher costs for such rolling stands because the rolls are worn out more quickly. In rolling stands with no or insufficient radial adjustability, worn rolls have to be reworked with a greater amount of material removed. Unfavorable rolling programs also require more extensive material removal in such rolling stands.

The invention is based on the problem of creating a rolling mill for rolling metal tubes, rods or wires which does not suffer from the disadvantages mentioned, but which can be subjected to higher loads and which can be adapted to the changing requirements of the operation more quickly and with less expenditure of work, time and costs.

This problem is solved according to the invention by a rolling mill for rolling metal pipes, rods or wires with several rolling stands arranged closely one behind the other in a straight line, which can be quickly replaced together, in groups or individually, and each of which has at least three rollers arranged in a star shape around a rolling axis, which are each driven by its own motor and drive shaft in all rolling stands, whereby the rollers are supported by means of multi-part roller shafts and can be replaced without dismantling the rolling stand housing and roller bearings. The combination of the features mentioned is particularly important.

This creates a rolling mill that can bear significantly higher loads with the same dimensions of its rolls and rolling stands, because all rolls of all rolling stands in the rolling mill have their own drive shaft, are driven directly by their own motor and thus the bevel gears for transmitting the torque to the individual roll shafts are eliminated. This means that within the equilateral triangles formed by the axes of rotation of the rolls, those

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Spaces are freed up that would otherwise be required by the bevel gears. These now free spaces can be used in whole or in part for the roller bearings, so that they can be made larger and thus have a higher load-bearing capacity, without having to enlarge the triangles formed by the axes of rotation of the rollers and thus the rollers themselves. The larger roller bearings therefore permit higher rolling forces with rollers of the same size and a consistently small distance between the rolling stands. In addition, the torques acting on the rollers are now independent of the transmission capacity of the bevel gears and can also be larger. As a result, rolled stock with higher strength and at a lower rolling temperature can be rolled. The rolling stands can also be manufactured with less effort and assembled more easily, eliminating the need for bevel gears and other individual parts.

The multi-part design of the roller shafts allows the rollers to be clamped axially between the facing faces of two partial shafts. This avoids the use of strength-reducing connections between rollers and roller shafts with keys and similar elements, as are often used. Above all, however, the multi-part design of the roller shafts enables rollers to be changed quickly. To do this, the axial clamping force between the two partial shafts is removed, they are only moved apart slightly and the rollers can be removed from the roll stand in a radial direction. Another roller can then be inserted radially into the roll stand between the two partial shafts and clamped there. The roll stand housing and/or the roller bearings do not need to be dismantled. Such a quick roll change in turn means that fewer roll stands can be used overall, because the preparation time for a new use for the roll stands not in the rolling mill is so short that they are already available again when the roll stands in use need to be replaced. Therefore, the new rolling mill will hardly require more than two sets of rolling stands. In addition, the quick and easy roll change also makes it possible to rework the rolls in the installed state and to

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The special machine required is no longer necessary because the rolls can be quickly removed and installed for reworking on standard machine tools. In addition, since all the rolling mill stands can be quickly replaced together, in groups or individually, the rolling mill downtime is kept to a minimum and only for a short period of time.

In a preferred embodiment of the invention, the rolling stands have a one-piece rolling stand housing. This is possible with the individual drive of the rolls according to the invention and the resulting absence of bevel gears. Consequently, the rolling stand housings can be manufactured with considerably less effort because the partial surfaces that have to be carefully machined in several steps and sealed to the outside are eliminated, as are the numerous holes for dowel pins and connecting screws that otherwise have to hold the two parts of the rolling stand housing together with a precise fit.

In the rolling mill according to the invention, the rolls of all the rolling stands, of only some of the rolling stands, or of none of the rolling stands can be radially adjusted. Which of these options is chosen depends on the rolling program and the respective operating conditions for which the rolling mill is to be suitable. It is particularly advantageous, however, if the roll bearings are arranged in eccentric bushings in all rolling stands and these can be rotated in stages to adjust the rollers radially and locked in several rotational positions. In this way, several distances are available between the rolling axis and the rotation axes of the rolls in all rolling stands. In such a rolling mill, rolls with a worn working surface can even be reworked to the same caliber shape and size as the original and reused. The rolling stands can be adjusted to the smaller ideal roll diameters that inevitably arise during reworking and thus different distances between the rolling axis and the roll rotation axes by rotating the eccentric bushings. The rolls

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can not only be reused somewhere else, but also at the same stand location and with the same caliber opening. The relatively expensive rolls can thus be used much more frequently and better utilized, which significantly reduces the roll costs. The radial adjustment of the rolls can be achieved with little effort in the rolling mill according to the invention without bevel gears. It is preferably carried out outside the rolling line, for example in a stand workshop.

It is also recommended that the roller bearings be arranged in eccentric bushings at least on the two last rolling stands on the outlet side and that these be designed to be continuously radially adjustable for the continuous radial adjustment of the rollers, even when the rolling stands are installed and ready for operation, regardless of whether the rollers on the other rolling stands are radially adjustable in stages or not. This has the advantage that all conceivable finished dimensions of the rolled stock can be produced within the production area of the rolling mill and in any order. It is even possible to change the finished dimensions to a limited extent without changing the rollers or rolling stands. But even with this design, it is sensible to provide a step-by-step radial adjustment outside the rolling mill for all or some of the rolling stands whose rollers are not continuously radially adjustable when the rolling stand is installed and ready for operation.

As a rule, the number of rolling stands whose rolls are not continuously radially adjustable when the rolling stand is installed and ready for operation is greater than the number of rolling stands with continuously radially adjustable rolls. This reduces the effort and costs involved in constructing the rolling mill by using as few complex rolling stands with continuously radially adjustable rolls as possible.

It is also advisable for the rolling stands, whose rolls are not continuously adjustable radially when the rolling stand is installed and ready for operation, to use rolls with a

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have a different ideal roll diameter than the rolling stands with continuously radially adjustable rolls. This improves the possibilities of reusing reworked rolls and also saves roll costs.

It makes sense if all stand positions are suitable for rolling stands with continuously adjustable radial rolls and for rolling stands with non-continuously adjustable radial rolls. All rolling stands can then be used in all stand positions and the rolling mill can be optimally adapted to the respective requirements.

In a recommended design, the drive shafts of the rolls and the shafts of their motors extend coaxially to the respective roll rotation axis. It is particularly advantageous if the motors, whose shafts form an angle to the horizontal and assume the same angular position with one another, are arranged on, on or in a common frame. This simplifies the devices for coupling and uncoupling the rolling stands with the drive of their rolls when changing the rolling stands. This also speeds up the changing of the rolling stands themselves and shortens the uneconomical downtimes of the rolling mill. It is expedient to arrange reduction gears on, on or in the common frame between the motors and the drive shafts of the rolls. It has proven advantageous to design the reduction gears as planetary gears.

In a further embodiment of the invention, the reduction gears of several or all motors with the same angular position are combined in a housing that is designed as a common frame. In this case, several or all motors with the same angular position can also be flanged to the housing of the reduction gears, which is designed as a common frame. In another embodiment, the motors and reduction gears of one or more rollers, whose roller rotation axes form an angle to the horizontal, are each combined to form a drive unit.

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It is particularly advantageous if the common frame or drive units can be moved linearly in the direction of the rollers' assigned rotation axes. However, it is also possible to pivot the common frame or drive units about a pivot axis extending parallel to the roller axis. An articulated gear can also be provided for pivoting the common frame or drive units.

In addition, it is advantageous if the common frame or drive units arranged above the rolling axis are held by a concrete support bridge. Such a support bridge offers all options for fastening the frames or drive units and has a dampening effect on any vibrations that may occur.

A stand changing device is provided so that the rolling stands can be easily and quickly removed from the rolling line of the rolling mill, either together, in groups or individually, and replaced with other rolling stands if necessary. In a recommended design, one or more rolling stands are on one or more stand changing carriages, from which they can be moved into the rolling line and onto which they can be moved out of the rolling line. The stand changing carriages are responsible for moving the rolling stands in or against the rolling direction along the rolling mill. They can also be used to transport the rolling stands from the rolling mill to a stand workshop and back.

In this embodiment of the rolling mill, the drive for moving the rolling stands can be arranged below the motors and, if necessary, the reduction gears for the rolls with horizontally extending axes of rotation, whereby the drive has a number of horizontally extending working cylinders which can be coupled optionally to the rolling stands assigned to them on a stand changing carriage or in a stand holder of the rolling mill. As an alternative

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For this purpose, the drive for moving the rolling stands can be given two horizontally extending working cylinders which are arranged in the area of the inlet and outlet end faces of the rolling mill and which engage a transport beam arranged on the operating side of the rolling stands, extending parallel to the rolling axis and displaceable transversely to it, to which each rolling stand can be optionally coupled.

In another embodiment of the rolling mill, one or more rolling stands are on one or more stand changing carriages, with which the rolling stands can be moved in and out of the rolling line. The stand changing carriages also serve to hold the rolling stands during rolling.

The invention is illustrated in the drawings using several embodiments. It shows:

Figure 1 shows a rolling mill according to the invention in plan view;

Figure 2 is a section along the line II - II of Figure 1;

Figure 3 shows a rolling mill corresponding to Figure 2, but with a pivoting upper roller drive;

Figure 4 shows a rolling mill corresponding to Figure 3, but with a different roll changing device and in side view;

Figure 5 shows a rolling mill corresponding to Figure 3, but with an articulated gear for pivoting the upper roller drive.

In Figure 1, a rolling mill 1 has a large number of rolling stands 2, some of which are arranged closely one behind the other on a stand changing carriage 3 in the situation shown. The rolling stands 2 on the stand changing carriage

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3 come from a scaffolding workshop where the rolling stands 2 are prepared for use in the rolling mill 1 and from where they are placed on the scaffold changing carriage 3 in the required order. Tracks 4 lead to the rolling mill 1. In front of this there is a second scaffold changing carriage 5 with empty scaffold holders 6 because its rolling stands 2 are in the rolling mill 1 and therefore cannot be seen in the plan view in Figure 1. These rolling stands 2 are moved all, in groups or individually as required after their use from the rolling mill 1 onto the scaffold changing carriage 5, which is then moved to the side so that the scaffold changing carriage 3 with its other rolling stands 2 can drive in front of the rolling mill 1. The rolling stands 2 located on the scaffold changing carriage 3 and required in the rolling mill 1 can then be brought to their scaffolding locations in the rolling mill 1.

In Figure 2, the stand changing carriage 5 can be seen in cross-section and the position of a rolling stand 2 on the stand changing carriage 5 is shown in dot-dash lines after it has been removed from the rolling mill 1. In fact, the rolling stands 2 in Figure 2 are still in their operating position. Three rolls 7 are arranged in a star shape in each of the rolling stands 2, which surround a straight horizontal rolling axis 8, which can only be shown as an intersection point in Figure 2.

All rollers 7 are driven separately. They are each driven by a drive shaft 9 from a motor 10. Reduction gears 11, which are designed as planetary gears here, are provided between the drive shafts 9 and the motors 10. The drive shafts 9, motors 10 and reduction gears 11, which are shown without reference numbers, are assigned to an adjacent rolling stand 2.

At each stand, below the motors 10, the reduction gears 11 and the drive shafts 9 for the rolls 7 with horizontally extending axes of rotation, there is a working cylinder 12 which also extends horizontally and which can be optionally coupled to the rolling stand 2 assigned to it.

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so that it can be pushed out of the rolling mill 1 onto a stand changing carriage 3, 5 or pulled into the rolling mill 1 by such a stand changing carriage 3, 5.

The motors 10 and reduction gears 11, whose shafts form an angle to the horizontal and which assume the same angular position with one another, are arranged on or on a common frame 13. By means of further working cylinders 14, the frames 13 can be moved linearly in the direction of the axes of rotation of the rollers 7 assigned to them. Couplings 15 allow the drive shafts 9 to be separated and coupled from roller shafts 16, which are located almost entirely in the rolling stands 2 and are therefore barely visible in Figure 2. When the working cylinders 14 are appropriately subjected to pressure medium, the common frames 13 and with them the motors 10, the reduction gears 11 and the drive shafts 9 are moved far enough away from the rolling stands 2 that the parts of the couplings 15 can be separated and the rolling stands 2 can be moved horizontally, e.g. onto the stand changing carriage 5. In the process, the couplings 15 of the horizontally extending drive shafts 9 are also released. In a corresponding manner, the roller shafts 16 of the rolling stands 2 can be coupled again with the drive shafts 9 after the rolling stands 2 are in their operating position. The frames 13 are then moved by the working cylinders 14 towards the rolling stands 2 until the parts of the couplings 15 engage with each other again.

The common frame 13 arranged above the rolling axis 8 in Figure 2 is held by a concrete support bridge 17. This is not the case in the embodiment according to Figure 3. There, the common frame 13 arranged above the rolling axis 8 is held by at least one swivel arm 18, which can be swiveled about a swivel axis 19 extending parallel to the rolling axis 8, whereby the swivel movement can be carried out by both working cylinders and motors, which are not shown in Figure 3. The swivel movement of the upper frame 13 not only triggers

the couplings 15, but it can be so extensive that the area above the rolling stands 2 is free and the rolling stands 2 can be grasped from above with a hall crane and thus replaced. It is then possible to manage without a stand changing carriage 3, 5. Otherwise, the design according to Figure 3 corresponds to that of Figure 2.

Figure 4 shows the rolling mill of Figure 3, but with a different device for quickly changing the rolling stands 2. On the operating side of the rolling stands 2 there is a transport beam 20 which extends parallel to the rolling axis 8 and can be moved transversely to it. The transport beam 20 is driven by two working cylinders 21 which can be pressurized, one of which is arranged in the area of the inlet and outlet end faces of the rolling mill 1, so that only one of the two can be seen in Figure 4. With a latch 22 arranged at each stand location, which can be pivoted about a joint 23, each rolling stand 2 can be coupled to the transport beam 20 as desired. For this purpose, the latch 22, which can be pivoted by hand, engages in a recess 24 of the relevant rolling stand 2. When changing rolling stands 2, the transport beam 20 is moved together with the coupled rolling stands 2 onto the stand changing carriage 5. The transport beam 20 is then uncoupled from its working cylinders 21 and these are moved back to their starting position. The stand changing carriage 5 can then be driven to the scaffolding workshop together with the transport beam 20. The other stand changing carriage 3 with prepared rolling stands 2 also brings a transport beam 20 to which the working cylinders 21 are coupled as soon as the stand changing carriage 3 is in the correct position in front of the rolling mill 1. The prepared rolling stands 2 can then be moved into the rolling mill 1 with the help of the transport beam 20.

The embodiment of the rolling mill of Figure 5 differs from that of Figure 3 only by an articulated gear 25 for holding and moving the upper frame 13 instead of the pivot arm(s) 18.

Claims (23)

1. Rolling mill for rolling metal pipes, bars or wires with several rolling stands ( 2 ) arranged closely one behind the other in a straight line, which can be quickly replaced together, in groups or individually and each of which has at least three rollers ( 7 ) surrounding a rolling axis ( 8 ) in a star shape, which are each driven in all rolling stands ( 2 ) by their own motor ( 10 ) and their own drive shaft ( 9 ), wherein the rollers ( 7 ) are mounted by means of multi-part roller shafts ( 16 ) and can be replaced without dismantling the rolling stand housing and roller bearings. 2. Rolling mill according to claim 1, characterized in that the rolling stands ( 2 ) have a one-piece rolling stand housing. 3. Rolling mill according to claim 1 or 2, characterized in that in all rolling stands ( 2 ) the roller bearings are arranged in eccentric bushings and these can be rotated step by step for the radial adjustment of the rollers ( 7 ) and can be locked in several rotational positions. 4. Rolling mill according to claim 1 or 2, characterized in that at least in the two last rolling stands ( 2 ) on the outlet side, the roller bearings are arranged in eccentric bushings and these can be adjusted continuously radially for the continuous radial adjustment of the rollers ( 7 ) even when the rolling stands ( 2 ) are installed and ready for operation. 5. Rolling mill according to claim 4, characterized in that for all or some of the rolling stands ( 2 ) whose rollers ( 7 ) are not continuously radially adjustable when the rolling stand ( 2 ) is installed and ready for operation, a step-by-step radial adjustment is provided outside the rolling mill ( 1 ). 6. Rolling mill according to claim 4 or 5, characterized in that the number of rolling stands ( 2 ) whose rollers ( 7 ) are not continuously radially adjustable when the rolling stand ( 2 ) is installed and ready for operation is greater than the number of rolling stands ( 2 ) with continuously radially adjustable rollers ( 7 ). 7. Rolling mill according to one of claims 4 to 6, characterized in that the rolling stands ( 2 ) whose rollers ( 7 ) are not continuously radially adjustable when the rolling stand ( 2 ) is installed and ready for operation have rollers ( 7 ) with a different ideal roller diameter than the rolling stands ( 2 ) with continuously radially adjustable rollers ( 7 ). 8. Rolling mill according to one of claims 4 to 7, characterized in that all stand positions are suitable for rolling stands ( 2 ) with continuously radially adjustable rolls (7) and for rolling stands ( 2 ) with non-continuously radially adjustable rolls ( 7 ). 9. Rolling mill according to one of claims 1 to 8, characterized in that the drive shafts ( 9 ) of the rolls ( 7 ) and the shafts of their motors ( 10 ) extend coaxially to the respective roll rotation axis. 10. Rolling mill according to one of claims 1 to 9, characterized in that the motors ( 10 ), the shafts of which form an angle to the horizontal and assume the same angular position among themselves, are arranged on, on or in a common frame ( 13 ). 11. Rolling mill according to claim 10, characterized in that reduction gears ( 11 ) are arranged on, on or in the common frame ( 13 ) between the motors ( 10 ) and the drive shafts ( 9 ) of the rolls ( 7 ). 12. Rolling mill according to claim 11, characterized in that the reduction gears ( 11 ) are designed as planetary gears. 13. Rolling mill according to claim 11 or 12, characterized in that the reduction gears ( 11 ) of several or all motors ( 10 ) with the same angular position are combined in a housing which is designed as a common frame ( 13 ). 14. Rolling mill according to claim 13, characterized in that several or all motors ( 10 ) are flanged with the same angular position to the housing of the reduction gears ( 11 ) designed as a common frame ( 13 ). 15. Rolling mill according to claim 11 or 12, characterized in that the motors ( 10 ) and reduction gears ( 11 ) of one or more rolls ( 7 ), the roll rotation axes of which form an angle to the horizontal, are each combined to form a drive unit. 16. Rolling mill according to one of claims 10 to 15, characterized in that the common frame or frames ( 13 ) or drive units can be moved linearly in the direction of the roller rotation axes assigned to them. 17. Rolling mill according to one of claims 10 to 15, characterized in that the common frame(s) ( 13 ) or drive units can be pivoted about a pivot axis ( 19 ) extending parallel to the rolling axis ( 8 ). 18. Rolling mill according to claim 17, characterized in that articulated gears ( 25 ) are provided for pivoting common frames ( 13 ) or drive units. 19. Rolling mill according to one of claims 10 to 18, characterized in that the common frame ( 13 ) or drive units arranged above the rolling axis ( 8 ) are held by a supporting bridge ( 17 ) made of concrete. 20. Rolling mill according to one of claims 1 to 19, characterized in that one or more rolling stands ( 2 ) are located on one or more stand changing carriages ( 3 , 5 ), from which they move into the rolling line and onto which they can be moved out of the rolling line. 21. Rolling mill according to claim 20, characterized in that the drive for moving the rolling stands ( 2 ) is arranged below the motors ( 10 ) and optionally the reduction gears ( 11 ) for the rolls ( 7 ) with horizontally extending axes of rotation, and that it has a number of horizontally extending working cylinders ( 12 ) which can be coupled optionally to rolling stands ( 2 ) assigned to them on a stand changing carriage ( 3 , 5 ) or in a stand holder ( 6 ) of the rolling mill ( 1 ). 22. Rolling mill according to claim 20, characterized in that the drive for moving the rolling stands ( 2 ) has two horizontally extending working cylinders ( 21 ) which are arranged in the region of the inlet and outlet side end faces of the rolling mill ( 1 ) and which engage a transport beam ( 20 ) arranged on the operating side of the rolling stands ( 2 ), extending parallel to the rolling axis ( 8 ) and displaceable transversely thereto, to which each rolling stand ( 2 ) can be selectively coupled. 23. Rolling mill according to one of claims 1 to 19, characterized in that one or more rolling stands ( 2 ) are located on one or more stand changing carriages ( 3 , 5 ) with which the rolling stands ( 2 ) can be moved into and out of the rolling line.