EP3831503B1 - Rolling system for cold pilgering - Google Patents

Description

The invention relates to a rolling mill for cold pilgrimage according to the preamble of claim 1.

DE 42 34 394 C1 describes a feed gear for a cold pilger rolling mill, in which collet chucks acting alternately on a workpiece can be driven and moved via spindles in a feed direction. A gear for rotating the spindles is arranged between the collets, which geometrically limits the minimum distance between the collets. The collets are oriented in the same direction.

DE-A1-21 16 604 describes a feed gear for a cold pilger rolling mill, in which two schematically shown collets are driven via spindles, wherein a spindle of the first collet has an opposite thread direction to that of a spindle of the second collet, so that the collets move in opposite directions when the connected spindles have the same direction of rotation.

DE-A1-24 24 907 describes a feed gear for a cold pilger rolling mill in which two collets are driven via spindles. The collets have the same orientation in relation to a feed direction.

DE-C1-33 04002 , which represents the basis for the preamble of claim 1, describes a feed gear for a cold pilger rolling mill, in which two schematically shown collet chucks are driven via spindles. The collets have the same orientation in relation to a feed direction.

The object of the invention is to provide a rolling mill for cold pilgering, in which particularly homogeneous processing is possible over a large feed length. This object is achieved according to the invention for a rolling mill mentioned at the beginning with the features of claim 1. The opposite orientation of the tendons makes it possible to keep a minimum distance between the points of attack of the two tendons on the billet or the workpiece particularly small.

By precisely measuring products rolled on conventional systems, in particular by means of eddy current testing, the effect of a change in the pipe wall when changing from one clamping slide to another could be observed in the form of a small jump. After the clamping slide was changed, the pipe wall then changed continuously with the forward movement of the clamping slide. By reducing the length of the workpiece under tension during the transfer, the jump could be reduced or eliminated.

A tendon in the sense of the invention is designed according to the principle of a collet, with the area of a force-locking engagement being closer to one of the ends of the tendon. Due to the opposite orientation of the collets, the two areas of the force-locking engagement are particularly close together at the moment of transfer.

A small distance between the clamping elements is also advantageous in the outer reversal positions of the clamping slides. This dimension can be minimized by suitable control. To do this, the clamping slide whose clamping element is not currently gripping the workpiece must grip the workpiece again as soon as possible after reaching its starting position. In this way, it can be ensured that the two clamping slides, and thus the two clamping elements, do not move further away from each other than absolutely necessary.

A rotary drive of a clamping member or a collet for rotating the workpiece can be controlled by a servo motor mounted on each clamping slide Alternatively, a common drive shaft can be used, e.g. below a rolling center, which in turn is driven by a servo motor.

At least one of the clamping slides is driven via at least one spindle and a spindle nut, which is preferably arranged on the clamping slide. Driving the tensioning slides of cold pilger rolling mills by means of one or more spindles has generally proven successful and can be easily combined with the design of the tensioning members according to the invention.

A co-moving drive motor, in particular for driving the spindle nut, is arranged on at least one of the clamping slides. The drive motor that moves along with it is designed as a hollow shaft motor surrounding the spindle. Modern motors are characterized by high torques and universal controllability. A design as a hollow shaft motor, particularly for directly driving the spindle nut without a gearbox, makes optimal use of these properties.

In a preferred embodiment of the invention, a minimum distance between an attack of the first tendon and an attack of the second tendon on the blank is smaller than the sum of the lengths of the two tendons. Particularly preferably, the minimum distance is smaller than the length of one of the tendons. Even more preferably, the minimum distance is less than half the length of one of the tendons. The smaller the minimum achievable distance, the smaller the jump caused by elasticity when the blank is transferred from one tendon to the other tendon.

In order to facilitate a minimal distance between the tendons in a simple way, it is generally advantageous not to arrange a gear between the two tensioning carriages.

In a first possible development of the invention, the two clamping slides can each have a two-sided, preferably have a symmetrically designed drive. This type of design allows particularly high and symmetrically introduced forces, making it particularly suitable for large billet diameters or large feed forces.

In an advantageous detailed design, a continuous spindle is arranged on each side of the drive, on which each of the two clamping slides is supported. This enables a small number of components and support bearings to be used.

In an alternative detailed design of the invention, each of the two clamping slides is supported on a separate, preferably driven pair of spindles. This allows the use of shorter spindles and a particularly high level of independence in the movement control of the clamping slides.

In general, the drive of spindle nuts on both sides of a clamping slide can also be mechanically coupled, so that the number of electric motors is reduced.

In a second possible development of the invention, it is provided that the two clamping slides each have a one-sided drive, preferably on different sides. This allows a simple and cost-effective drive to be realized. A one-sided drive exerts a moment on each clamping slide with respect to the center of the roll, so that such a solution is particularly suitable for smaller blank diameters or lower feed forces.

A possible embodiment of the invention provides that the feed device comprises a stationary gear for driving the spindle. A particularly variable drive can be achieved by such a gear, which is preferably not arranged between the clamping carriages. A rotating and/or translationally oscillating drive can be implemented with the gearbox.

Particularly preferably, it can be provided that the spindle experiences a translational movement, with the spindle nut being additionally rotatable in a drivable manner. Translational movements of the spindle can be advantageous for suitable Movement sections of the overall complex, sectional feed movement of the blank can be used in the cold pilgrimage process.

In a generally advantageous development of the invention, it can also be provided that the feed device has at least two mandrel bearings for holding a mandrel rod, with at least one of the mandrel bearings, preferably the first mandrel bearing, being adjustable in position by an adjustment path, in particular a maximum length the travel is more than 20% of the distance between the mandrel bearings. Even more preferably, the length of the adjustment path can be more than 30% of the distance between the mandrel bearings. As a result, the rolling system can be adapted to blanks of different lengths, with the advantages of a homogeneous feed load according to the invention remaining.

Fig. 1

zeigt eine schematische Darstellung einer Walzanlage zum Kaltpilgern nach dem Stand der Technik.

Fig. 2

zeigt eine Anordnung zweier Spannschlitten einer Walzanlage gemäß einem ersten erläuternden Beispiel.

Fig. 3

zeigt eine Anordnung zweier Spannschlitten einer Walzanlage gemäß einem zweiten erläuternden Beispiel.

Fig. 4

zeigt eine Anordnung zweier Spannschlitten einer Walzanlage gemäß einem dritten erläuterndem Beispiel.

Fig. 5

zeigt eine Anordnung zweier Spannschlitten einer Walzanlage gemäß einem vierten erläuterndem Beispiel.

Fig. 6

zeigt eine Schnittansicht durch ein Spannglied eines Spannschlittens.

Several examples are described below for explanation purposes, each of which, however, does not have a hollow shaft motor according to the invention, and is explained in more detail with reference to the accompanying drawings.

Fig. 1

shows a schematic representation of a rolling mill for cold pilgrimage according to the state of the art.

Fig. 2

shows an arrangement of two clamping carriages of a rolling mill according to a first explanatory example.

Fig. 3

shows an arrangement of two clamping carriages of a rolling mill according to a second explanatory example.

Fig. 4

shows an arrangement of two clamping carriages of a rolling mill according to a third explanatory example.

Fig. 5

shows an arrangement of two clamping carriages of a rolling mill according to a fourth explanatory example.

Fig. 6

shows a sectional view through a tendon of a tensioning slide.

In the Fig. 1 The rolling mill shown for cold pilgrimage is previously known. It comprises a roll stand 1 for rolling a blank (not shown) by means of cold pilgers and a feed device 2, the blank being moved through the roll stand 1 by means of the feed device 2 during the rolling process.

The feeding device 2 comprises a first clamping member 3 of a first driven clamping slide 4 and a second clamping member 5 of a second driven clamping slide 6. The clamping members 3, 5 are alternately fixed to the billet, so that the billet is first moved by one stroke of the first clamping slide 4 and subsequently by one stroke of the second clamping slide 6 in a feed direction V. While the feed is carried out by the clamping slide 4, 6 engaging the billet, the other clamping slide 4, 6 is moved back to its starting position. Through this alternating feed by the two clamping slides 4, 6, a billet of quasi-infinite length can be pushed through the rolling stand 1.

The drive of the clamping slides 4, 6 guided on rails or flat sliding surfaces is effected by means of a gear 7 which, in the present case of the prior art, is arranged between the two clamping slides 4, 6.

In the rolling stand 1, the forming of the billet takes place in a known manner according to the cold pilger process. The rolling stand 1 is moved in an oscillating manner by a drive 1a. The billet usually undergoes a step-by-step rotation in addition to a linear feed.

In Fig.1 Also shown above the clamping slide 4, 6, guide means 8, mandrel bearing 9 and other components as used in conventional cold pilger rolling mills.

In Fig. 2 is a further development of a rolling mill Fig. 1 shown, with only the area of the clamping slide 4, 6 being shown schematically. The first clamping carriage 4 is in an outer end position opposite to the feed direction (in Fig. 2 left), and the second clamping slide 6 is in an outer end position in the feed direction (in Fig. 2 right). In addition, a part of each clamping slide 4, 6 is shown again in an opposite, inner end position in order to clarify the movement of the clamping slides 4, 6.

The first clamping slide 4 moves by a stroke H1 between its end positions, and the second clamping slide 6 moves by a stroke H2, which is the same size, between its end positions. The front edges of the two clamping slides facing each other have a maximum distance L (both clamping slides 4, 6 in the outer end position). A minimum distance A of the front edges of the clamping slides 4, 6 in the inner end positions results in L-(H1+H2).

According to the invention, the first tendon 3 is oriented opposite to the second tendon 5. The tendons 3, 5 are each arranged with one end, at which a releasable force-locking engagement with the billet takes place, on the edge of their tensioning carriage 4, 6 directed towards the other tensioning carriage. For the first, front (in Fig.2 left) clamping slide 4 this is the right edge, and for the second, rear (in Fig.2 In the case of the (right) tensioning carriage 6, this is the left edge. The locations of the force-locking action of the tendons 3, 5 on the shell thus approximately coincide with the Fig.2 marked position lines for the strokes H1, H2 and the length L.

The opposite orientation of the tendons 3, 5 makes it possible to keep a minimum distance A = L-(H1+H2) between the points of attack of the two tendons on the billet or the workpiece particularly small.

By precisely measuring products rolled on conventional systems, in particular by means of eddy current testing, the effect of a change in the pipe wall when changing from one clamping slide to another could be observed in the form of a small jump. After the clamping slide was changed, the pipe wall then changed continuously with the forward movement of the clamping slide. By reducing the length of the workpiece under tension during the transfer, the jump could be reduced or eliminated.

Like in particular Fig. 6 shows, the tendons 3, 5 in the present case are designed according to the principle of a collet chuck, with the area of a non-positive attack being closer to one of the ends of the collet chuck. A conical clamping member 10 is radially compressed or compressed by means of a displaceable conical sleeve 11. opened, with the collet chuck 3, 5 attacking the blank by means of the clamping member. A relative displacement of the sleeve 11 to the clamping member 10 takes place by means of a hydraulic lever mechanism 12. Off Fig. 6 It can be seen that the clamping member 10 is located close to one end of the tendon 3, with a total structural length of the tendon 3, 5 being a multiple of the length of the clamping member 10.

Due to the opposite orientation of the tendons or collets 3, 5, the two areas of the force-fitting attack can have a particularly small distance at the moment of a transfer.

A rotary drive 13 of the tendon or the collet chuck 3, 5 for rotating the workpiece can be done via a servo motor (not shown) mounted on each clamping slide. Alternatively, a common drive shaft can also be used, e.g. below a rolling center, which in turn is driven by a servo motor.

The minimum distance A between an attack of the first tendon 3 and an attack of the second tendon 5 on the hole is in the present case smaller than half the length of one of the tendons 3, 5. The smaller the minimum achievable distance A, the smaller the fall through Elasticity-related jump when the blank is transferred from one tendon 3, 5 to the other tendon 3, 5.

In order to facilitate the minimum distance A between the tendons in a simple way, no gear is required between the two tensioning slides 4, 6 (unlike in Fig.1 ) are arranged.

The clamping slides 3, 5 are each driven by a spindle 14, 15. The spindles 14, 15 each interact with a spindle nut 16, 17 arranged on the clamping slides 4, 6. The drive of the clamping slides of cold pilger rolling mills by means of one or more spindles has generally proven to be successful and can be easily combined with the inventive design of the clamping members 3, 5.

In the example after Fig.2 it is provided that the two clamping slides 4, 6 each have a one-sided drive, in this case on different sides. The first spindle 14 extends on one side of the clamping slides 4, 6 over the entire length of both clamping slides, and the second spindle 15 extends in the same way on the other side. The spindles 14, 15 are each driven at one end by means of an electric drive 18, 19. At the opposite end, the spindles 14, 15 are each rotatably mounted in an abutment 20, 21.

The first spindle 14 only interacts with the spindle nut 16 of the first clamping slide 4. The second spindle 15 only interacts with the spindle nut 17 of the second clamping slide 6.

This allows a simple and cost-effective drive to be implemented. The one-sided drive exerts a moment on each clamping slide 4, 6 with respect to the roll center, so that such a solution is particularly suitable for smaller shell diameters or lower feed forces.

The electric drives 18, 19 can be designed as directly acting electric motors or as combinations of electric motors and gears. Depending on the requirements, both a rotational movement of the spindles 14, 15 and a translational movement can be provided.

At the in Fig. 3 In the second example shown, there is a movement sequence of the clamping slides 4, 6 that is identical to the first example. Regarding the distances L, H1 and H2 as well as the structure and function of the tendons 3, 5, reference is also made to the first example.

The differences to the first example only concern the design of the drive by means of the spindles 14, 15. In the example according to Fig.3 the spindles 14, 15 are not driven, but are completely housed in fixed bearings 22. The drive of the clamping slides 4, 6 is carried out by driven rotating and arranged on both sides Spindle nuts 16, 16' of the first clamping slide 4 and similar spindle nuts 17, 17' of the second clamping slide 6.

Thus, the two clamping slides 4, 6 each have a symmetrical drive on both sides with respect to a rolling center. Each of the clamping slides is supported on each side in a driven manner on one of the spindles 14, 15. Such a design allows particularly high and symmetrically applied forces, so that it is particularly suitable for large blank diameters or large feed forces.

Since a continuous spindle 14, 15 is arranged on each side of the drive, on which each of the two clamping slides 4, 6 is supported, a small number of components and support bearings is structurally possible.

A co-moving drive motor 24 for driving the spindle nuts 16, 16' is arranged on each of the clamping slides 4, 6. In the present case, the drive of the spindle nuts 16, 16' and 17, 17' on both sides of a clamping slide 4, 6 is mechanically coupled by means of a co-moving gear 23. In this way, only one electric motor 24 needs to be provided for each of the clamping slides 4, 6.

In the embodiment of the invention (not shown), the co-moving drive motor or each of the co-moving drive motors of the respectively driven spindle nuts 16, 16', 17, 17' can be designed as a hollow shaft motor enclosing the spindle 14, 15. Modern motors are characterized by high torques and universal controllability. A design as a hollow shaft motor, in particular for direct drive of the spindle nut without a gear, makes optimal use of these properties. This use of co-moving hollow shaft motors applies to every embodiment of the invention described here or any other embodiment, provided that driven spindle nuts are provided for driving at least one of the clamping slides 4, 6.

At the in Fig. 4 The example shown is different from the example after Fig. 3 provided that each of the two clamping slides 4, 6 is supported on a separate, driven pair of spindles. A first pair of spindles 14, 15 serves this purpose Drive of the first clamping slide 4, and a second pair of spindles 14 ', 15' is used to drive the second clamping slide 6, so that as in the example Fig. 3 there is a drive of the clamping slides 4, 6 supported on both sides. Overall, this allows the use of shorter spindles and a particularly high level of independence in the movement control of the clamping slides.

Another difference to the example according to Fig. 3 Each of the spindles 14, 14', 15, 15' is driven by means of electric drives 25. Each of the four spindles 14, 14', 15, 15' is assigned its own electric drive 25.

The spindles 14, 14' and 15, 15' arranged one behind the other in the feed direction V are accommodated in pivot bearings 26, which are each arranged between the clamping slides 4, 6. Such pivot bearings are small in size. In the inner end positions of the clamping slides, they can almost completely overlap with the clamping slides 4, 6 by means of suitable recesses, so that they do not conflict with the inventive concept of a small minimum distance A between the clamping slides 4, 6.

In the Fig.5 The example shown is an arrangement as in Fig.4 , whereby the individual drives of the rotating spindles 14, 14', 15, 15' are designed differently. The two spindles 14, 15 and 14', 15' of a clamping slide are mechanically coupled by a gear 27 for each clamping slide 4, 6. In this way, only one electric motor 28 needs to be provided for driving each clamping slide 4, 6.

In this example, the feed device thus comprises a stationary gear 27 for driving the spindles 14, 14 ', 15, 15'. A particularly variable drive can be achieved by such a gear 27, which is preferably not arranged between the clamping carriages.

In an embodiment not shown, it can also be provided that the spindles 14, 14 ', 15, 15' undergo a translational movement, with the spindle nuts also being rotatable in a drivable manner. Translational movements of the spindles 14, 14', 15, 15' can be advantageously used for suitable movement sections of the overall complex, section-wise feed movement of the blank in the cold pilgrimage process. Such a combination of translationally moved spindles with rotation in the spindle nuts can be provided in any arrangement of spindles according to the exemplary embodiments described above.

In each of the examples described above, it is also provided that the feed device 2 has at least two mandrel bearings 9 for holding a mandrel rod (not shown), wherein at least one of the mandrel bearings 9, preferably the first mandrel bearing, can be adjusted in its position by an adjustment path. A maximum length of the adjustment path of the adjustable mandrel bearing is more than 30% of a distance between the mandrel bearings 9. This allows the rolling mill to be adapted to billets of different lengths, while retaining the advantages of a homogeneous feed load according to the invention.

List of reference symbols

1

Roll stand

1a

Rolling mill drive

2

Feeding device

3

first tendon

4

first clamping slide

5

second tendon

6

second clamping slide

7

Gearbox (state of the art)

8th

Leading aids

9

Thorn bearing

10

clamping link

11

Sleeve

12

Lever mechanism

13

Rotary drive tendon

14

first spindle

14'

spindle

15

second spindle

15'

spindle

16

first spindle nut

16'

spindle nut

17

second spindle nut

17'

spindle nut

18

electric drive

19

electric drive

20

abutment

21

Abutment

22

Fixed bearing

23

moving gear on clamping slide

24

Electric motor on clamping slide

25

electric drive for spindle

26

Pivot bearing for spindle

27

stationary gear

28

Electric motor

Claims (10)

1. Rolling mill for cold pilger rolling, comprising

   a roll stand (1) for rolling a tube blank by means of cold pilger rolling, and a feed device (2), wherein the tube blank is moved through the roll stand (1) by means of the feed device (2) during the rolling process,

   wherein at least one first clamping element (3) of a first driven clamping slide (4) and at least one second clamping element (5) of a second driven clamping slide (6) are fixed to the tube blank in alternation so that the tube blank is initially moved through a stroke (H1) of the first clamping slide (4) and subsequently through a stroke (H2) of the second clamping slide (6), wherein each of the clamping elements is constructed according to the principle of a collet chuck, wherein the region of frictional engagement is in each instance closer to one of the ends of the clamping element, and wherein at least one of the clamping slides (4, 6) is driven by way of at least one spindle (14, 14', 15, 15') and spindle nut (16, 16', 17, 17') which is arranged particularly at the clamping slide (4, 6),

   characterised in that

   - the first clamping element (3) is oriented oppositely to the second clamping element (5) so that the two regions of frictional engagement at the moment of transfer can have a particularly small spacing; and

   - a conjunctively moved drive motor (24), particularly for drive of the spindle nut (16, 16', 17, 17'), is arranged at at least one of the clamping slides (4, 6); and

   - the conjunctively moved drive motor is configured as a sleeve shaft motor surrounding the spindle (14, 14', 15, 15').
2. Rolling mill according to claim 1, characterised in that a minimum spacing (A) between a point of engagement of the first clamping element (3) and a point of engagement of the second clamping element (5) at the tube blank is smaller than the sum of the lengths of the two clamping elements (3, 5), in particular smaller than the length of one of the clamping elements (3, 5).
3. Rolling mill according to one of the preceding claims, characterised in that no transmission is present between the two clamping slides (4, 6).
4. Rolling mill according to claim 3, characterised in that the two clamping slides (4, 6) each comprise a drive formed on either side of, particularly symmetrically with respect to, a roll centre.
5. Rolling mill according to claim 4, characterised in that arranged on either side of the drive is a continuous spindle (14, 15) on which in each instance each of the two clamping slides (4, 6) is supported.
6. Rolling mill according to claim 4, characterised in that each of the two clamping slides (4, 6) is supported on a separate, in particular driven, spindle pair (14, 14', 15, 15').
7. Rolling mill according to claim 3, characterised in that the two clamping slides (4, 6) each have a drive at one side, particularly on respectively different sides.
8. Rolling mill according to any one of claims 3 to 7, characterised in that the feed device (2) comprises an immobile transmission (27) for drive of the spindle (14, 14', 15, 15').
9. Rolling mill according to any one of claims 3 to 8, characterised in that the spindle (14, 14', 15, 15') undergoes a translational movement, wherein the spindle nut (16, 16', 17, 17') is in addition rotationally drivable.
10. Rolling mill according to one of the preceding claims, characterised in that the feed device (2) comprises at least two mandrel bearings (9) for mounting a mandrel rod, wherein at least one of the mandrel bearings (9), particularly the first mandrel bearing (9), is variably adjustable in its position over a setting path, wherein in particular a maximum length of the setting path is more than 20% of a spacing of the mandrel bearings (9).

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