KR20020034859A - Rotary drive of reciprocally transferable roller passes of a cold pilger rolling mill - Google Patents

Abstract

PURPOSE: A method for driving the roller pair of a cold pilger rolling mill is provided which realizes a substantially improved adjustment of the rolling curve of the pinion to the neutral zone within the tapering roll pass of the ring rollers. CONSTITUTION: In a method for adjusting a rolling curve of drive pinions of ring rollers to a neutral zone within a tapering portion of a roll pass of the ring rollers of a cold pilger rolling mill, the method comprises the step of arranging and securing circular pinions eccentrically on a roller axis of the ring roller, wherein the method further comprises the step of driving the circular pinions by sine-shaped tooth racks, and the method further comprises the step of adjusting one or more of the parameters selected from the group consisting of roller diameter, reference circle of the pinion, eccentricity, and angular position of the eccentricity relative to the approach dead center of the roll stand relative to the current roll dimensions.

Description

ROTARY DRIVE OF RECIPROCALLY TRANSFERABLE ROLLER PASSES OF A COLD PILGER ROLLING MILL}

The present invention relates to a method for adjusting the feed curve of a drive pinion to a neutral zone in a tapered pass of an annular roll of a cold pilger rolling mill.

Cold pilger rolling mills are long, drawable thin tubes with extremely eccentricity for thick film metal puddle balls, especially copper puddle balls, which are extruded, hot rolled or continuously cast in a rough rolling process for a relatively long period of time. Suitable for shrinking to

The cold pilger rolling method applied is a molding rolling method for metal tubes whose diameter and plate thickness are reduced in more forming steps.

At this time, the position is fixed at the time of rolling, the rolling mandrel tapering in the rolling direction is located on the inner surface of the tube. The rolled mandrel is fixed to a long length mandrel rod which is held fixed by one mandrel support.

The roll pair overlaps the tubular rolling stock located on the mandrel during forward / backward movement and roughly rolls the paste, similar to the pasty rollers during rolling and rough rolling.

The roll pair is supported in a roll stand which is reciprocally movable forward and backward and is driven by a pinion which is connected with the stand during stand movement. The pinion is engaged with two racks which are fixed. The roll passes are then rolled forward and backward in synchronization with the oscillating roll stand.

The roll pass itself is reciprocated back and forth by crankshaft driving like an engine piston. Roll passes are approximately circular and shrink across the roll surface in the case of a typical embodiment according to the prior art. The reduced or tapered cross section between the roll and the roll mandrel simultaneously reduces the diameter and plate thickness of the rolling stock.

In the region of at least one dead center of the two dead spots the rolls release the puddle ball for a short time, while at the same time the puddle ball is forwarded and / or simultaneously rotated, for example by approximately 60 °. In the above method, not only the forward stroke but also the return stroke is used for molding. The feed rate and rotation angle at these two dead points depend on the pipe material and the quality conditions. The average tensile strength of rolled tubes ranges from 400 N / mm ² to 1,500 N / mm ^{2 and} above for special alloys.

The basic diagram of the aforementioned tube rolling method is shown in simple schematic in FIGS. 2A-2D. Figure 2a is a view of the rolling rate in the forward stroke, Figure 2b is a notch cross-sectional view along the cut line A-B. Figure 2c is a diagram of the rolling rate during the return stroke, and Figure 2d is a cutaway cross-sectional view along cut line A-B.

By combining the in-line winding device and the cold pilger rolling machine, for example, a 250 m long coiled tube can be produced. At this time, the pipe discharged from the cold pilger rolling mill while the reciprocating rotation forward / backward by the forward feed according to the step is bent into a coil during the rolling process and stored directly in the cage required for the subsequent drawing process.

The forming process after the cold pilger rolling described above has significant advantages for a myriad of applications, despite the relatively low production rates:

The molding process sometimes exhibits relatively large cross-sectional rolling rates for diameter and plate thickness,

-The eccentricity is significantly reduced as a result of the flow being balanced in the circumferential direction,

-Optimize the material structure as a result of mechanical compensation when producing longer length tubes;

Longer pipe lengths can be produced.

The cold pilger rolling method for making tubes has improved roundness, balanced pressure uniformity and surface roughness in the following situations:

When achieving tight tolerances for diameter and plate thickness in rolling stock,

No material loss dependent on the process;

More heavy, with high economic efficiency by using long puddle balls, in applications for materials that are difficult to mold, and

-When manufacturing various finished product dimensions with one puddle ball dimension.

Nevertheless, as a result of the geometric relationship to the stroke length of the Peeler stage rolling mill in the prior art, the drawback of the passes when the radius of the drive wheels is not changed is disadvantageous from the fact that it changes in the rolling area in a wider area. Will occur. The passes then slip on the tube to be forcibly rolled, thereby degrading the quality of the tube. At this time, the axial thrust acting on the rolling stock, which continues to be a disadvantage, causes a series of problems. Therefore, it is difficult or impossible at all to roll the thin green piece using conventional forward feed. This is because the end faces of the raw piece are interlocked with each other when rolling, whereby the rolling mill performance is correspondingly degraded. The rolling mill is also subjected to high loads on all its functional members and is forcibly worn. In particular, roll and mandrel breakages occur and damage to the rolling mill requires costly repairs.

Another drawback of the prior art is that the feedback stroke of the roll stand can be used only with limited restrictions on the molding operation, because no matter how high the feedback rolling force usually occurs during the feedback stroke. This, in principle, prevents further forwarding of the important raw piece to be fully utilized in the discharge dead point area, thereby limiting the possible production capacity.

The prior art also limits the diameter rolling rates possible in the molding technique. Obviously, the diameter rolling rate increases, and also the pinion pitch circle that is not adjusted in place increases. This also adversely affects the economic efficiency of the cold pilger rolling method.

It is known in the prior art to assign to the actual roll dimensions a center of circular pinion and a roll diameter for the solution. Nevertheless, the above matters are not satisfactory in the improvement of the rolling process.

In contrast, German publication DE-OS 17 52 996 suggests the use of a spiral pinion. The pinion is engaged with a rack of inclined straight lines. Known solutions have the practical disadvantage of losing the usable aperture length and reducing roll performance. The solution is also associated with the straight shape of the rack. Nevertheless, since pass involvement follows a higher level of parabola, the point of approach to the target curve is also very limited here only.

It is an object of the present invention to provide a method for driving a roll pair of cold pilger rolling mill which, from the foregoing prior art, realizes in practice that the adjustment of the feed curve of the pinion to the neutral zone in the tapered pass of the annular roll is actually improved. Is in.

1 is a diagram schematically showing the geometric relationship over the stroke length of a cold pilger rolling mill,

2 is a view of a rolling method of the invention comprising a machining step, Figure 2a is a view of the rolling rate in the forward stroke, Figure 2b is a notch cross-sectional view along the cutting line AB, Figure 2c is a rolling rate in the return stroke 2D is a cutaway cross section along cut line AB.

In order to solve the above object, an annular pinion is used to adjust the feed curve of the drive pinion of the annular roll to the neutral zone in the tapered pass of the annular rolls according to the invention and the pinion is arranged eccentrically on the axis of the roll. A fixed point is proposed. With the present invention the following goals are achieved:

-Reduced pressure load on the feed slide,

Avoidance of uncontrolled forward feed by relative motion between the roll profile and the rolling stock,

-Reduced wear in roll profiles,

-Reduced energy consumption due to reduced friction

Neutral in tapered pass of annular rolls

Avoiding the still existing disadvantages of the known solutions.

One embodiment of the present invention is that a correspondingly sinusoidal rack is used to drive the pinion (and thus annular rolls).

The solution according to the invention as described above has the disadvantages of unsatisfactory methods and devices of the prior art, such as the roll pair slipping on a rolling stock with the above mentioned disadvantages for rolled products and rolling mills and reduced production capacity. Reduce or eliminate.

In another embodiment of the method according to the invention, the following four parameters, roll diameter, pinion pitch circle and eccentricity, are used when using a circular eccentric pinion correspondingly engaged with a sinusoidal rack. It is proposed that the rate and angular position of the eccentricity with respect to the inflow dead center of the roll stand are adjustable to the actual roll dimensions.

Detailed features and advantages of the present invention will be described in more detail with reference to the accompanying drawings and the following embodiments of the drawings.

(Example)

Such well known cold peeler processes are shown in FIGS. 2A-2D. The process serves to manufacture or deform one tube 12 while using cold pilger roller pairs 10, 10 ′. The roller pair is supported on a roller stand, not shown. The tube 12 to be processed is guided on a roll mandrel 13. The roll stand performs vibratory motion during the rolling process, while at the same time the stroke may be up to 300 times per minute, and more. The tube 12 is then deformed by its roll paths 11, 11 ′ into its full shape or to its final contour; The roll paths 11, 11 ′ are inserted in rolls 10 to 10 ′ which are opposite to each other over the entire outer circumference and within the roll gap (compare FIG. 2b and FIG. 2d) with the circumferential surface. It includes the tube 12 in a closed manner. In this case the roll paths 11 to 11 'have different widths and / or depths (as seen in the development of the roll surface) corresponding to their correction, and these points are shaded roll path contours 11 and 11. 'Is clearly shown in FIGS. 2A-2C.

The tube 12 is moved in the conveying direction R during rolling. During the forward stroke, schematically shown in FIG. 2A, the complementary cold pilger roll pair 10, 10 ′ rolls on the tube 12 in the conveying direction R, wherein the tube rolls 11, 11. It is enclosed within the roll gap of ('). During the return stroke, which is schematically shown in FIG. 2C, the rolling movement of the roll pairs 10, 10 ′ takes place on the tube 12 in the opposite direction of the conveying direction R (translational movement with the rotational direction 14 in the figures). Arrow comparison for directions).

In figure 1 the geometric relationship over the stroke length of a cold pilger rolling mill is shown schematically in diagram form. The diagram is based on the following data or parameters of the embodiment as follows:

Copper Rolled 87 x 11 to 40 x 2

Roll diameter 375 mm

Pinion Pitch One 336 mm

Stand stroke1,023 mm

Reduced diameter 600 mm

Full surface length 140 mm

Pinion Eccentricity 13 mm

Offset angle 140 degree

As path basic curves, path involute

A zone (1) in which the rolls apply to forward feed and rotate the rolling stock,

A reduction zone (2) according to a parabolic function,

Cylindrical smooth surface area (3),

The rolling stock consists of a transition part 4 which can be further rotated and / or forwarded.

Curve 5 shows the neutral axis from which the longitudinal forces resulting from the different feed rates are neutralized.

The portion of the rolling stock between the pass base and the neutral axis overlaps at a relatively low speed, while the portion between the roll diameter 6 and the neutral axis 5 overlaps at a higher rate.

The pinion pitch circle, which can follow the curve 5, can likewise neutralize the longitudinal force resulting from the feed rate that changes over the aperture length. The centered circular pinion 7 may only be incompletely close to the above conditions. This is because a portion of the circumferential speed that is too large prevails in the front pass area, whereas the circumferential speed is too low in the smooth area of the smooth area 3. Only when the roll involute is approximately 120 ° the ratio is temporarily correct.

Nevertheless, if the pinions are arranged eccentrically in a suitable manner according to the invention (8), a particularly broad approach to the targeted curve (5) is achieved, and the tendency of the rolling stock to be broadly neutralized. The roll surface can be used without limitation, and the curve shape is actually further improved than is possible in the prior art to follow the target curve.

According to the method of the present invention, a broad approach to the target curve is achieved, and the movement trend of the rolling stock is also broadly neutralized to adjust the feed curve of the pinion to the neutral zone in the tapered path of the annular roll. It can be greatly improved.

Claims (3)

A method for adjusting the feed curve of a drive pinion of an annular roll to a neutral zone in a tapered pass of an annular roll of a cold pilger rolling mill, wherein in this case a circular pinion is used and the pinion is eccentrically positioned and fixed to the roll axis. Characterized in that the method. The method according to claim 1, wherein correspondingly sinusoidal racks are used to drive the pinion (and thus the annular roll). The method according to claim 1 or 2, wherein the following four parameters are used in the use of a circular eccentric pinion which meshes with correspondingly sinusoidal racks: Roll diameter Pinion Peach One Eccentricity The angular position of the eccentricity with respect to the inflow dead center of the roll stand is adjustable to the actual roll dimensions.