EP2216107B1 - Drive system for a milling system, in particular a cold pilger milling system - Google Patents

Description

The invention relates to a drive system for a rolling mill, in particular for a cold pilger rolling mill, with the features specified in the preamble of the independent claim, as by the DE 18 15 521 A1 known.

Another drive system in which the two crank mechanisms no separate drive is assigned, for example, from DE 43 36 422 C2 known. 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. However, this weight is usually not sufficient for a sufficient balance of mass forces

The productivity of a cold pilgering mill is directly dependent on the number of strokes of the mill stand per unit time, which is why it is necessary to aim for the greatest possible number of working strokes per minute for reasons of economy. However, this also means large inertial forces that burden both the drive system and especially its bearings as well as the foundation and thus the environment. In the aforementioned prior art solution is therefore provided that the crank mechanism via a toothing drives another shaft on which a counterweight is arranged eccentrically with respect to the center of gravity. This countermass runs counter to the rotation of the crank mechanism and is 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 is both in this known embodiment, as well as in the version with hydraulic motors as drives according to the generic document DE 18 15 521 A1 in that, overall, a rather complicated construction of the entire drive system results, because a large number of machine elements - intermeshing via toothing - 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 the DE-PS 962 062 a drive system for a cold pilger rolling mill is known in which the crank arm for driving the rolling mill with flyweights and a vertically oscillating balance weight to compensate for the mass forces of the first order and the mass moments in the drive is equipped. 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.

The DE 36 13 036 C1 discloses a drive for the mill stand of a cold pilger mill using a planetary crank drive to drive and balance mass and mass moments. 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.

From the DE 101 47 046 C2 is known a drive system for a cold pilger rolling mill, which uses separate shafts with counterweights to improve the mass balance, these shafts are driven by a drive that are independent of the drive of the crank mechanism. The synchronization of the shafts during operation of the rolling mill is done electronically. However, the effort to be made is not insignificant.

In known drive systems for cold pilger rolling mills, two-cranked, expensive crankshafts are therefore used which move the rolling stand in an oscillating manner via push rods. The balancing weights on the crankshaft and on additional rotating additional shafts eliminate the mass forces caused by the rolling motion of the rolling mill.

The invention is therefore based on the invention to design a generic drive system in particular for a cold pilger rolling mill so that the mass forces - at least the first order - can be kept as low as possible in a simplified and thus cost-effective design.

This object is achieved in that the own drive of the two units is designed as electric motors that drive the crank mechanisms directly from the drive shaft without mechanical connection of the crank cranks of the two crank mechanisms.

The two units are preferably formed mirror-image to the center plane.

The electric motor is preferably designed as a low-speed, high-torque motor.

The crank mechanism is preferably designed as a non-limited crank.

The proposed drive system is preferably free of further waves with balancing weights.

The masses of the balance weights can be selected so that the first-order framework mass forces are at least substantially, preferably completely, compensated during operation of the drive system.

The advantage is that the required crank mechanisms are very simple. In particular, it does not require the special crank mechanisms which are typically used in the previously known drives for cold pilger mills. In particular, can be dispensed with doubly cranked crankshafts, which are complicated and expensive.

Furthermore, a separate balance shaft can be omitted, as is known in the art.

The entire system can build shorter by the proposal according to the invention.

The drive system according to the invention makes the mechanical connection of the two crankshafts of the crank mechanisms dispensable. The crank mechanisms are designed as unrestricted cranks; the push rod joint to the rolling mill thus moves on a straight line which passes through the axis of rotation of the crank. Both cranks are preferably driven by separate motors. The cranks have an opposite sense of rotation, which is why alone with the balancing weights on the cranks mass forces of the first order can be fully compensated. An additional shaft with counterweights can be omitted assuming opposite rotation of the cranks.

Fig. 1

die Seitenansicht eines Antriebssystems für ein Kaltpilgerwalzwerk mit Walzgerüst, bei dem zwischen dem Antrieb und dem Kurbeltrieb ein Getriebe in Form eines einstufigen Stirnradgetriebes angeordnet ist, im Schnitt A-B gemäß Fig. 2;

Fig. 2

die zu Fig. 1 zugehörige Draufsicht auf das Antriebssystem;

Fig. 3

eine Seitenansicht eines Antriebssystems für ein Kaltpilgerwalzwerk mit Walzgerüst nach der Erfindung im Schnitt C-D gemäß Fig. 4; und

Fig. 4

die zu Fig. 3 zugehörige Draufsicht auf das Antriebssystem.

In the drawings 3 and 4 an embodiment of the invention is shown, wherein it is in the in the Fig. 1 and 2 shown variant is not an embodiment of the invention, but an example that facilitates the understanding of the invention. Show it:

Fig. 1

the side view of a drive system for a cold pilger rolling mill with roll stand, in which a transmission in the form of a single-stage helical gear is arranged between the drive and the crank mechanism, in section AB according to Fig. 2 ;

Fig. 2

the too Fig. 1 associated plan view of the drive system;

Fig. 3

a side view of a drive system for a cold pilgering mill with rolling mill according to the invention in section CD according to Fig. 4 ; and

Fig. 4

the too Fig. 3 associated plan view of the drive system.

In the Figures 1 and 2 shows a drive system for a rolling mill, which does not fall below the intended scope. A drive system 1 is used to drive a cold pilger rolling mill, of which a rolling stand 2 is shown, which is in the horizontal direction oscillating back and forth to perform the known cold pilger rolling process.

The oscillating drive of the roll stand 2 takes place with two mirror images of a vertically aligned center plane 8 (s. Fig. 2 ) arranged units, each consisting of a crank mechanism 3 'and 3 ", a crank arm 4' and 4", a balance weight 5 'and 5 "and a push rod 7' and 7" exist. These units are known as such for driving a cold pilger mill.

In contrast, here two of these units are arranged in mirror image and are each driven by a drive 6 ', 6 "in the form of an electric motor, in opposite directions, while the crank mechanism 3' of the one unit rotates on one side of the center plane 8, for example in a clockwise direction , the crank mechanism 3 "of the other unit on the opposite side of the center plane 8 moves counterclockwise.

There are two electric motors 6 ', 6 "are used, each of which drives a single-stage spur gear 9' and 9" the crank mechanisms 3 'and 3 ".

The rolling stand 2 is acted upon by two push rods 7 ', 7 ", which in turn are driven in opposite directions via the two crank mechanisms 3', 3" by the separate motors 6 ', 6 ". 5 "of the crank mechanisms 3 ', 3" rotate in opposite directions, so that mass forces of the first order can be completely compensated.

In the FIGS. 3 and 4 a first embodiment of the drive system according to the invention is shown. Here, gearbox 9 ', 9 "has been dispensed with between the motors 6', 6" and the crank mechanisms 3 ', 3 ", ie the drive of the crank mechanisms 3', 3" takes place directly from the drive shaft of the motors 6 ', 6 ". The waiver of the reduction stage of the transmission 9 ', 9 "is favored or made possible by the use of low-speed and high-torque motors.

This eliminates all gears and the corresponding gear housing, so that an even simpler structure of the drive system is achieved.

LIST OF REFERENCE NUMBERS

1

drive system

2

rolling mill

3

crankshaft

3 '

crankshaft

3 '

crankshaft

4

crank

4 '

crank

4 '

crank

5

counterweight

5 '

counterweight

5 '

counterweight

6

drive

6 '

drive

6 "

drive

7

pushrod

7 '

pushrod

7 "

pushrod

8th

midplane

9 '

transmission

9 "

transmission

Claims (5)

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

   - at least one reciprocating roll stand (2),

   - at least one crank mechanism (3) that features a crank arm (4) with a balancing weight (5) in order to at least partially compensate the inertial forces generated by the roll stand (2),

   - at least one drive (6) and

   - at least one pushrod (7) that connects the roll stand (2) and the crank arm (4) to one another in an articulated fashion,

   wherein two units consisting of a crank mechanism (3', 3"), a crank arm (4', 4"), a balancing weight (5', 5") and a pushrod (7', 7") are provided and arranged to both sides of the center plane (8) of the drive system (1), with said units being driven in opposite directions by the at least one drive (6),
   and wherein each of the two units features a separate drive (6', 6"), by means of which the two units are driven in opposite directions,
   characterized in
   that the separate drives of the two units are realized in the form of electric motors (6, 6") that directly drive the crank mechanisms (3, 3") from the drive shaft without a mechanical connection of the cranks of the shafts of the two crank mechanisms (3', 3").
2. The drive system according to Claim 1,
   characterized in
   that the two units are realized in a mirror-inverted fashion referred to the center plane (8).
3. The drive system according to Claim 1 or 2,
   characterized in
   that the electric motor (6', 6") is realized in the form of a slow-speed, high-torque motor.
4. The drive system according to one of Claims 1 to 3,
   characterized in
   that the crank mechanism (3', 3") is realized in the form of a non-crossed thrust crank.
5. The drive system according to one of Claims 1 to 4,
   characterized in
   that the masses of the balancing weights (5', 5") are chosen such that the first-order inertial forces of the roll stand are at least largely compensated, preferably entirely compensated, during the operation of the drive system (1).

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