EP1396292B1 - Drive system for a cold pilger mill - Google Patents

Abstract

Drive system, for a cold reciprocating rolling mill with a reciprocating roller stand (2), has at least one crank drive (4) from a drive (3). The crank arm has a balance weight (6) for at least a partial compensation of the mass forces generated by the roller stand, with a push rod (7) linking the crank arm and roller stand. At least one counter mass (8) with an eccentric rotation is synchronized with the crank drive movements, through a gearing (9,10), to compensate for the moving masses and/or the mass inertias. A single counter mass is used for the crank drive, with the movements of the balance weight and the counter mass on identical planes.

Description

The invention relates to a drive system for a cold pilger rolling mill, comprising a reciprocating roll stand, at least one driven by a drive crank mechanism having a crank arm with balance weight for at least partially balancing the mass forces generated by the rolling stand and a push rod, the rolling stand and the crank arm articulated to each other, and at least one counterweight which is eccentrically rotatably arranged for compensating mass forces and / or moments of inertia, and a transmission synchronizing the movement of the crank mechanism and the counterweight.

A drive for a cold pilger mill is known for example from DE 43 36 422 C2. To carry out the cold pilgering process, a mill stand equipped with a cold pilger roller pair is required, which is driven in an oscillating manner. For this purpose, a crank mechanism is used, which is driven by a motor. The crank mechanism is provided to compensate for the inertial forces of the roll stand with a balance weight.

The productivity of a cold pilger mill is directly dependent on the number of strokes of the rolling stand per unit time, which is why it must be sought for reasons of economy, to achieve the largest possible number of strokes per minute. However, this also means large inertial forces that burden both the drive system and in particular its bearings as well as the foundation and thus the environment.

In the cited DE 43 36 422 C2 it is therefore provided that the crank drive via toothing drives further waves on which countermeasures are arranged eccentrically with respect to the center of gravity. These countermeasures run in the same direction and in opposite directions upon rotation of the crank mechanism and are thus able to generate compensating mass forces or moments of inertia, so that the overall result is a balance of force in the entire drive system.

A disadvantage of the known embodiment that overall results in a rather complicated construction of the entire drive system, because a variety of machine elements - intermeshing intermeshing - are required. This also increases the cost of the drive system and thus of the cold pilger rolling mill, which means not only the investment costs for the system itself, but also the costs for the plant foundation, for spare and wearing parts and for maintenance and repair.

From DE-PS 962 062 a drive system for a cold pilger rolling mill is known in which the crankshaft is equipped to drive the rolling mill with centrifugal weights and a vertically oscillating balance weight to compensate for the mass forces of the first order and the mass moments in the drive.

The disadvantage of this solution is that the foundation of the rolling mill is very complicated and therefore expensive designed, since it must be ensured for the vertical immersion of the balance weight in the foundation. This requires a large and deep basement, which increases the costs of the rolling mill accordingly.

DE 36 13 036 C1 discloses a drive for the rolling stand of a cold pilger rolling mill, wherein a planetary drive for driving and balancing of inertial forces and moments of inertia is used.

Although with this solution, an optimal mass balance can be done, this drive is only suitable for smaller cold pilger mills, because in larger systems, the size of such a drive system increases disproportionately and thus causes high costs.

Also from DE 41 24 691 C1 (& EP-A-0524711) a generic drive system for a cold pilger rolling mill is known. This is characterized by the fact that the crank mechanism consists of three parallel to each other and equally spaced waves, of which the middle formed as a crankshaft shaft is connected via its crank pin with the rolling stand coupling push rod and its crank by 180 degrees to the articulation point of the push rod offset a inertial forces of the rolling stand in half balancing main mass is arranged eccentrically to the axis of rotation of the crankshaft. Furthermore, there is provided that two equally large additional masses are arranged on the other two waves, which compensate for the other half of the inertial forces of the rolling stand.

All known drive systems for cold pilger mills therefore have the serious disadvantage that quite a lot of effort to reduce the mass forces or moments of inertia is operated, so that high investment or foundation costs and / or a complex assembly during manufacture or during repair and maintenance of the rolling mill are conditional.

It has been found that the previously known, sometimes quite elaborately designed systems for the compensation of inertial forces and moments of inertia are sometimes not necessary if the environment is not very sensitive to vibrations.

The invention is therefore based on the object to design a drive system for a generic cold pilger rolling mill so that the simplest possible and therefore less expensive construction is given, the mass forces and inertia can be limited by such a structure, however, to a reasonable degree.

This object is achieved in that the crank mechanism is assigned only a single counterweight, wherein the plane in which moves the balance weight of the crank mechanism during rotation, and the plane in which the counterweight moves during rotation, are identical, wherein the Crankshaft, the counterweight and the drive via gear transmission are interconnected, wherein the drive via the gear drive drives a shaft to which the counterweight is connected, and wherein the arranged on the shaft gear of the gear transmission via a gear drives a shaft with which the Crank drive is connected, and wherein the balance weight and / or the counterweight is arranged as an eccentrically arranged mass in one of the gears of the gear transmission.

With this configuration, a very simple construction of the drive system for a cold pilger mill is achieved overall. Nevertheless, it is ensured that a sufficient Massenkraft- and mass moment compensation takes place, so that an acceptable operating condition of the rolling mill is given.

Advantageously, it is provided that the shaft of the crank mechanism, the shaft of the counterweight and the shaft of the drive lie in one plane, whereby a particularly simple and easily mountable structure can be realized.

According to a first structural embodiment of the drive system, the rolling stand and a single crank mechanism can be connected to each other by a single push rod. It is recommended in terms of a particularly simple structure, when the push rod is cantilevered on the crank mechanism.

In an alternative embodiment, the rolling stand and a single crank mechanism can be interconnected by two push rods, which are mounted on both sides of the crank mechanism flying. Here can be provided with advantage that the center plane (plane of symmetry) of the rolling stand and the center plane (plane of symmetry) of the crank mechanism are identical; Furthermore, the center plane (plane of symmetry) of the crank mechanism and the center plane (plane of symmetry) of the counterweight are preferably identical.

A further alternative embodiment provides that the roll stand and two crank drives arranged on both sides of the crank mechanism arranged symmetrically to the center plane of the roll stand are connected to one another by two push rods. In this case, it can further be provided that the drive via gear transmission connects the two crank mechanisms and the two counterwebs assigned to them, the gear mechanisms being arranged laterally adjacent to a crank mechanism.

The shafts of the crank mechanism, the counterweight and the drive can be arranged horizontally or vertically.

The economic and efficient, as automatic as possible supply of the push rod bearings and the bearings of the work rolls in the rolling mill is of major importance. It is therefore provided according to a development that the push rod is mounted on journals, wherein at least one bearing pin is provided with at least one bore for supplying the bearing between the thrust rod and journal with lubricating oil.

For optimal operation of the drive system, it is proposed here that the masses of the roll stand, the balance weight (or the balance weights) and the counterweight (or counterweights) are selected so that the first-order framework mass forces are at least substantially equalized during operation of the drive system become.

The proposed drive system for a cold pilger mill is characterized by a simple structure, which ensures economical production and economic operation of the rolling mill. The quality of the mass balance is sufficiently good, so that a good quality of the pipes to be produced is made possible. The drive system therefore operates relatively low vibration, so that the foundation and the environment are treated gently. The drive system works reliably and has a long service life; the costs for maintenance and repair are low.

The assembly costs of the drive system are low due to the proposed structure of the system. Likewise, no special demands are placed on the foundation.

Fig. 1a

schematisch die Seitenansicht eines Kaltpilgerwalzenpaars während des Vorhubs des Kaltpilgerwalzprozesses;

Fig. 1b

die entsprechende Ansicht gemäß Fig. 1a während des Rückhubes;

Fig. 2a

eine Seitenansicht und

Fig. 2b

die zugehörige Draufsicht auf ein Antriebssystem für ein Kaltpilgerwalzwerk;

Fig. 3a

eine Seitenansicht und

Fig. 3b

die zugehörige Draufsicht auf eine Ausführungsform des Antriebssystem gemäß der Erfindung;

Fig. 4a

eine Seitenansicht und

Fig. 4b

die zugehörige Draufsicht auf ein Antriebssystem; und

Fig. 5a

eine Seitenansicht und

Fig. 5b

die zugehörige Draufsicht auf eine Ausführungsform eines Antriebssystems.

In the drawings 3a and 3b, an embodiment of the invention is shown, wherein the embodiments shown in FIGS. 2 a, 2 b, 4 a, 4 b and 5 a, 5 b are not exemplary embodiments of the invention but are examples which facilitate the understanding of the invention. Show it:

Fig. 1a

schematically the side view of a pair of cold pilger rollers during the Vorhubs the cold pilger rolling process;

Fig. 1b

the corresponding view of Figure 1a during the return stroke.

Fig. 2a

a side view and

Fig. 2b

the associated plan view of a drive system for a cold pilgering mill;

Fig. 3a

a side view and

Fig. 3b

the associated plan view of an embodiment of the drive system according to the invention;

Fig. 4a

a side view and

Fig. 4b

the associated plan view of a drive system; and

Fig. 5a

a side view and

Fig. 5b

the corresponding plan view of an embodiment of a drive system.

In Fig. 1a and Fig. 1b, the Kaltpilgerwalzprozess is shown schematically. It is used for manufacturing or forming a tube 22 by means of a cold pilger roller pair 23, which is mounted in a rolling mill, not shown here. The pipe 22 to be processed is guided on a rolling mandrel 24. The rolling mill performs an oscillating motion during the rolling process, whereby stroke frequencies of up to 300 per minute and more are possible.

The tube 22 is moved in the conveying direction R during the rolling process. During the pre-stroke, which is sketched schematically in FIG. 1a, the cold pilger-roller pair 23 rolls on the pipe 22 in the conveying direction R; during the return stroke, which is sketched in Fig. 1b, the rolling of the pair of rollers 23 on the tube 22 takes place counter to the conveying direction R (see arrows for the direction of rotation and direction of translation).

In Fig. 2a and Fig. 2b, a drive system 1 is sketched for a rolling stand 2 in side view and top view, in which the roller pair 23 shown in Fig. 1a, 1b is mounted.

To carry out the cold pilger rolling process, the rolling stand 2 must perform an oscillating movement - ie a reciprocating movement. For this purpose, a crank mechanism 4 is provided, which has a crank arm 5 with at least one offset and with a with respect to the bearing point eccentrically arranged balance weight 6. Crankshaft 4 and rolling mill 2 are connected to a push rod 7, which is articulated both on the crank arm 5 and on the roll stand 2.

The oscillatory drive of the roll stand 2 proceeds as follows: In a common plane 25, three shafts 12, 13 and 14 are arranged and supported next to one another. The shaft 14 is connected to a drive 3, which is not shown in detail; this can be an electric motor. The shaft 12 supports in an eccentrically arranged counterweight 8. The shaft 13 finally supports the crank mechanism 4, as explained above. On each of the three shafts 12, 13 and 14, a spur gear 9, 10 and 11 are rotatably arranged in each case. The gear 9 forms, together with the gear 10, a first gear transmission; Similarly, the gear 10 forms with the gear 11, a second gear transmission. As can be seen from FIG. 2 b, the toothed wheels 9, 10 and 11 are all in engagement, so that the drive 3 drives the shaft 13 and the counter mass 8 connected thereto when the shaft 14 rotates. The shaft 12 drives via the gears 9 and 10 in turn the shaft 13 and thus the crank drive 4 at.

In operation of the drive system 1, the shaft 12 and with it the counterweight 8 rotates in opposite directions with crank speed to the crank mechanism 4, whereby the mass balance is achieved.

It is essential that the crank mechanism 4 is assigned only a single counterweight 8, wherein during rotation of the crank mechanism 4, the rotation of the counterweight 8 is synchronized. Further, the plane 26, s. Fig. 2b, in which the balance weight 6 of the crank mechanism 4 moves during rotation, and the plane 27, s. Fig. 2b, in which the counterweight 8 moves during rotation, identical.

A simple structural design is achieved because crank mechanism 4, counterweight 8 and drive 3 via gear transmission 9, 10, 11 are interconnected. As already mentioned, drives the drive 3 via a gear transmission 10, 11, the shaft 12 to which the counterweight 8 is connected; on the other hand drives the arranged on the shaft 12 gear 10 of the gear transmission 10, 11 via the gear 9, the shaft 13 to which the crank mechanism 4 is connected. The shaft 13 the crank drive 4, the shaft 12 of the counterweight 8 and the shaft 14 of the drive 3 are preferably in the common plane 25, s. Fig. 2a.

The balance weight 6 and the counterweight 8 are designed so that the mass forces of the first order for the system consisting of roll stand 2, balance weight 6 and counterweight 8 are compensated when the drive system 1 moves. On the other hand, second and higher-order inertia forces arising from the oscillating movement of the roll stand 2 are not compensated. Also, no provision is made to compensate for the moment which produces the centrifugal force components of the counterweights acting perpendicular to the thrust direction of the rolling stand. The same applies to the moments that arise because the resultant of the inertial forces of the balance weights is not on the same line of action as the inertial force of the roll stand to be compensated.

The proposed drive concept has a deliberately lower quality of the mass balance, as it is usually the case in the solutions according to the prior art. However, this disadvantage does not particularly affect smaller machines, since the amplitudes of the forces and moments emitted via the foundation are sufficiently low. Impairment of the environment is only possible in the case of installation sites with particularly sensitive vibration. In these cases, but also with the previously known solutions vibration analysis and, where appropriate, additional measures are required.

In a particularly advantageous manner, the solution according to FIG. 2 a or FIG. 2 b operates with a single push rod 7, which is mounted on the crank mechanism 4 in a flying manner. The sketched arrangement of the push rod 7 in the center plane 15 of the rolling mill requires either a correspondingly low positioning of the system, consisting from crank drive 4, counterweight 8 and drive 3, or a suitable deflection of the produced tube from the roller center.

It is also important for an economical operation of the cold pilger rolling mill that automatic lubrication of the bearings of the push rod and the bearings of the work rolls in the rolling stand can take place. For this purpose, in Fig. 2b - only very schematically - outlined that extend through the crank of the crank mechanism 4 has two holes 20 and 21. Through these holes 20, 21, the bearings can be supplied with lubricating oil, which connect the bearing pins 18 and 19 to rolling stand 2 and crank mechanism 4 with the push rod 7.

Through the supply of lubricating oil through the holes 20, 21 can be dispensed with a production stop for relubrication of the bearings; relubrication can rather be done during operation of the drive system. Another particular advantage that can be achieved with this embodiment is that a reliable separation of lubricating oil and coolant can be achieved.

FIGS. 3a and 3b show an embodiment of the drive system 1 according to the invention. Here are the rolling stand 2 side two push rods 7 and 7 'are arranged, which are also mounted laterally and flying on the crank mechanism 4. The center plane 15 of the roll stand 2, the center plane 16 of the crank mechanism 4 and the center plane 17 of the counterweight 8 are identical. This ensures that no unbalanced mass moments arise when the mass of the rolling stand 2 and the mass of the balance weight 6 and the counterweight 8 move relative to each other.

As can be seen in Fig. 3a, the gears 9, 10, 11 are below the roller center. The balance weight 6 is arranged in the illustrated case as arranged eccentrically in the gear 9 mass; the balance weight 6 is thus in the gear 9 integrated. In the same way, the counterweight 8 is arranged as eccentrically arranged mass in the gear 10.

In the embodiment according to FIG. 4a or FIG. 4b, it can be seen that the principle of the push rods 7 or 7 'mounted on the crank mechanism 4 has been abandoned: the push rods 7, 7' are here with two crank drives 4 and 4 'in FIG Connection. On the side of a crank mechanism 4, the gear unit consisting of the gear drives 9, 10 and 10, 11 and the drive 3 is arranged. Each crank mechanism 4 and 4 'with a balance weight 6 or 6' is assigned a counterweight 8 or 8 ', which is driven synchronized to balance the mass by means of the gears 9, 10, 11.

The resultant of the centrifugal forces all balancing weights 6, 6 'and counterweights 8, 8' are due to the symmetrical structure in the center plane 15 of the rolling stand, so that the also lying in the center plane 15 mass force of the roll stand 2 can be optimally balanced.

The alternative embodiment according to FIGS. 5a and 5b shows that a construction can also be realized in which the shafts 12, 13 and 14 are arranged vertically; in the solutions according to Figures 2, 3 and 4, however, these waves are positioned horizontally.

The proposed drive system 1 thus has a very simple structure, which causes only low investment costs. Furthermore, the maintenance costs are relatively low due to the simple machine concept. On the other hand, a good balance of inertial forces and mass moments is possible, so that a low-vibration operation of the cold pilger rolling mill is possible without much effort. The availability of the rolling mill is high. The production of low-cost manufactured high-quality cold piled pipes is thus ensured.

LIST OF REFERENCE NUMBERS

1

drive system

2

rolling mill

3

drive

4

crankshaft

4 '

crankshaft

5

crank

6

counterweight

6 '

counterweight

7

pushrod

7 '

pushrod

8th

to ground

8th'

to ground

9, 10

Transmission (gear transmission)

10.11

Transmission (gear transmission)

9

gear

10

gear

11

gear

12

wave

13

wave

14

wave

15

Center plane (symmetry plane) of the roll stand

16

Center plane (symmetry plane) of the crank mechanism

17

Center plane (symmetry plane) of the countermass

18

pivot

19

pivot

20

drilling

21

drilling

22

pipe

23

Cold pilger roll pair

24

rolling mandrel

25

level

26

level

27

level

R

conveying direction

Claims (9)

1. A drive system (1) for a cold rolling pilger mill, with

   - a rolling stand (2) that is movable back and forth,

   - at least one crank mechanism (4, 4') that is driven by a drive unit (3) and is equipped with a crank arm (5) having a balancing weight (6, 6') to at least partly balance the inertial forces generated by the rolling stand (2) and a driving rod (7, 7') that connects the rolling stand (2) and the crank arm (5) to each other in articulated manner,

   - at least one counterweight (8, 8') disposed rotatably and eccentrically to balance inertial forces and/or inertial moments, and a transmission (9, 10) that synchronizes the movement of the crank mechanism (4, 4') and the counterweight (8, 8')

   characterised in that
   only one counterweight (8, 8') is attached to the crank mechanism (4, 4')
   wherein the plane in which the balancing weight (6, 6') of the crank mechanism (4, 4') moves during rotation and the plane in which the counterweight (8, 8') moves during rotation are identical,
   wherein the crank mechanism (4, 4'), the counterweight (8, 8') and the drive unit (3) are connected to each other via gear mechanisms (9, 10, 11), wherein the drive unit (3) drives a shaft (12) via the gear mechanism (10, 11), the shaft being connected to the counterwight (8, 8'), and wherein the gearwheel (10) of the gear mechanism (10, 11) that is disposed on the shaft (12) drives a shaft (13) via a gearwheel (9), the shaft being connected to the crank mechanism (4, 4'),
   wherein the balancing weight (6, 6') and/or the counterweight (8, 8') is/are disposed as an eccentrically situated mass in one of the gearwheels (9, 10) of the gear mechanisms (9, 10, 11).
2. The drive system as recited in claim 1,
   characterised in that
   the shaft (13) of the crank mechanism (4, 4'), the shaft (12) of the counterweight (8, 8'), and a shaft (14) of the drive unit (3) lie in one plane.
3. The drive system as recited in claim 1 or 2,
   characterised in that
   the midplane (15) of the rolling stand (2) and the midplane (16) of the crank mechanism (4, 4') are identical.
4. The drive system as recited in claim 3,
   characterised in that
   the midplane (16) of the crank mechanism (4, 4') and the midplane (17) of the counterweight (8, 8') are identical.
5. The drive system as recited in any of claims 1 to 3,
   characterised in that
   the rolling stand (2) and two crank mechanisms (4, 4') situated symmetrically about the midplane (15) of the rolling stand (2) and on either side thereof are connected to one another via two driving rods (7, 7').
6. The drive system as recited in claim 5,
   characterised in that
   the drive unit (3) connects the two crank mechanisms (4, 4') and the two counterweights (8, 8') attached thereto via gear mechanisms (9, 10, 11), wherein the gear mechanisms (9, 10, 11) are laterally adjacent a crank mechanism (4).
7. The drive system as recited in any of claims 1 to 6,
   characterised in that
   the shafts (12, 13, 14) of the crank mechanism (4, 4'), of the counterweight (8, 8'), and of the drive unit (3) are disposed horizontally.
8. The drive system as recited in any of claims 1 to 6,
   characterised in that
   the shafts (12, 13, 14) of the crank mechanism (4, 4'), of the counterweight (8, 8'), and of the drive unit (3) are disposed vertically.
9. The drive system as recited in any of claims 1 to 6,
   characterised in that,
   the driving rod (7, 7') is supported on bearing journals (18, 19), wherein at least one bearing journal (18, 19) is provided with at least one bore hole (20, 21) for supplying the bearing point between the driving rod (7, 7') and the bearing journal (18, 19) with lubricating oil.

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