DE102018211311A1 - Extended regulation JCO molding press - Google Patents

Abstract

Method for producing slotted tubes (4; 104) from sheet metal sheets (3), in particular thick sheet metal sheets, a sheet metal sheet being fed to a pipe forming press (1) in which it rests on a lower tool (6) by a lifting and lowering upper tool (9 ) is progressively formed by the application of a bending force to the slotted tube (4; 104) having opposite longitudinal edges for later longitudinal seam welding with a gap (11; 111), whereby
A slotted tube with an out-of-round preform (13) is produced by at least one means given on the left and right on the inside of the sheet metal plate (3) in relation to the upper tool (9) immersed in the longitudinal axis of the progressively molded sheet metal sheet (3). an indentation is carried out
characterized in that
The individual contour is determined for each sheet of metal, whereupon using a geometry model for the right and left side of the slotted tube, parameters for supporting tube positioning, in particular the angle of rotation and / or the length of rotation, as well as by online recording and evaluation of the pressure During the forming process, the yield point is determined on each side of the sheet and the dimension of the bending step acting on the inside and left of the sheet is determined.

Description

The invention relates to a method for producing slotted tubes from sheet metal sheets, in particular thick sheet metal sheets, a sheet metal sheet being fed to a pipe forming press in which it rests on a lower tool, progressing from a liftable and lowerable upper tool by applying a bending force, to that leading to a later longitudinal weld is formed with a slot tube having opposed longitudinal edges. Furthermore, the invention relates to a device for performing the method.

The pipe forming process with progressive forming or bending on pipe forming presses belongs to the process used in practice for the production of pipes from sheet metal. A tube forming or tube bending press usually has in a base frame a lower tool consisting of two supporting or bending bodies arranged next to one another at a lateral spacing, and a vertical tool that can be adjusted against the lower tool from above and is supported over the entire length by a lifting and lowering bending bar the metal sheet extending upper tool with which a bending force can be applied to the metal sheet resting on the lower tool.

For the manufacture of a pipe or large pipe according to the progressive molding process, several successive work steps are required. In a first step, the metal sheet is pre-bent on the longitudinal edges, usually in a separate edge bending press. The longitudinal edges are pre-bent so that the tube radius is evenly shaped when it is deformed into a slotted tube in the area of the subsequent seam, where the longitudinal edges of the sheet metal sheet bent over to the tube lie opposite one another for longitudinal seam welding with a gap. The sheet metal sheet which has been pre-bent in this way is then pushed into the tube forming press and subjected to the actual bending process there. In this case, a bending force is applied to the metal sheet by pressing down on the upper part of the press, a deformation of the metal sheet occurring under the action of the bending sword and the upper molding tool carried by it. This process is repeated several times until the metal sheet has been formed into the slotted tube.

Through the DE 42 15 807 C2 has become known in a frame construction tube bending or tube forming press. The sword, which is designed as a bending tool, is guided vertically in the side stands of the frame. This upper bending tool is gimbal-mounted to a small extent on piston-cylinder units and is supported by them against the upper frame cross member. The supporting bodies of the lower bending tool are supported by a table which is also supported by piston-cylinder units which act coaxially with the upper piston-cylinder units. The opposing piston-cylinder units are designed to prevent the table from bending, even if the lower frame crossbar should bend under the workload of the press. For this purpose, more or less pressure is applied to individual piston-cylinder units.

A very problematic in the advancing molding process has been a large residual gap of the slot of about 130 to 170 mm, which is significantly influenced by the width of the blade, particularly in the case of thick-walled tubes of, for example, 40 mm, and also stresses in the slot tube. A large slot width requires high closing forces in the tack welding device, and because of the high tensions in the tacked as well as residual tensions in the finished welded tube, there is a risk of a tearing tack or weld seam. If slot widths that are too large are recognized, remedial measures are taken to ensure that experienced machine operators have closed the slot as far as possible by repeatedly operating the tube forming press manually. This procedure is not only time-consuming with a correspondingly reduced throughput, but also cannot be carried out with reproducible good quality.

From the EP 2 529 849A2 A method and a device are known in which the slotted tube is produced with a non-circular preform, in which means act at least on the left and right on the inside of the sheet metal plate, at least in a means predetermined with respect to the upper tool dipping from the longitudinal axis into the progressively molded sheet metal sheet Bending step is carried out less than the other bending progress, whereby the finished slotted tube is formed by applying an external force to the non-circular preform in a targeted manner in the compressive force which previously had a smaller molding on both sides of the center. On the device side, a lower tool designed with reversible means in its direction of rotation and a stamp which can be acted upon from outside against the positioned preform are provided for forming the sheet metal sheet into a non-circular preform and then forming it into the slotted tube.

From R 2 543 657 a manufacturing method for longitudinally welded line pipes is also known, in which the shaping of the main contour of a front pipe made from coarse rolling stock, the subsequent connection of the longitudinal side edges of the formed front pipe, the welding of tabs and the welding of these side edges in closed position with the formation of a longitudinal connection seam and the expansion of the tube produced to maintain the outer contour, and in which after the outer contour of the front tube has been formed, its post-deformation is carried out in at least two stages, in a first stage from the starting position with that in the upper point of the circumferential gap of the side edges of the front pipe is rotated by an angle of 50 to 60 ° and fixed in this position, then a pressure force is applied in the upper area of the outer surface, which is distributed evenly over the length of the front pipe, which vertically displaces this area in the direction of the front tube axis by the size Δ = 0.1 - 0.4 S, where S is the size of the gap between the side edges of the front tube, which arises after the main contour has been formed, the force is then reduced and a rotation in the second post-forming stage the fore tube around the axis in the opposite direction around the same win relative to the vertical position of the gap as in the first stage, the down tube is fixed in this position, then a pressure force is applied to its upper area of the outer surface, which is evenly distributed over the entire length of the down tube, which vertically displaces this area in Direction of the front tube axis by the same size Δ as in the first stage, whereby if after the two post-deformation stages of the front tube the gap size between the side edges is larger than the maximum value permitted for this range, at least two post-deformation stages of the front tube, as in the first two Stages are carried out.

In practice, however, it has been found that differences in the yield strength across the metal sheet mean that slightly different slotted tubes arrive in the closing press after being formed. The slotted tubes sometimes have larger or smaller radii, which is noticeable in different slot widths. The radii can also be of different sizes on the left and right, which is problematic in that optimal operation of the closing press requires modified parameters both from tube to tube and from left to right.

The invention is therefore based on the object of creating a method and a system of the type mentioned at the outset without the disadvantages mentioned, in particular also in the case of thick-walled and small-diameter tubes, for example about 800 mm, to produce circular-cylindrical slotted tubes with reproducible quality create.

This object is achieved with a method with the features of claim 1 and with an apparatus with the features of claim 5.

By deliberately creating a non-circular preform that is initially tailored with low indentation in some areas, e.g. B. is generated with a bend of 12 ° instead of a bend of 24 °, a largely circular slotted tube geometry can be formed with a minimal slit. Due to the less molded areas, the prerequisite is created that the pressure subsequently applied from outside then has a significantly more sustainable effect in these less molded areas than in the other pipe sections and results in a largely circular slotted pipe with the desired tightly closed gap. In contrast to a dependency on the experience of the machine operator, consistent quality will both improve reproducibility and increase throughput.

Two bending steps or two squeezing processes can be sufficient both for area-wise non-circular preforming and for the final or finished molding, even in the final shaping with the squeezing force applied to the left and right of the gap or slot.

According to the invention, individual turning and pressing parameters are determined for each individual tube and for the two sides of the sheet metal to be molded. For slot tubes, the individual contour should be determined in order to determine tailored parameters for slot tube positioning, in particular the angle of rotation or the turning length, based on the respective current tube position using a corresponding geometry model for the right and left side of the slot tube. In addition, according to the invention, a real-time evaluation of the pressure-displacement curve allows conclusions to be drawn about the current yield point and thus about the required strokes both for the left and for the right side of the metal sheet. This means that different parameters for the rotations or the press stroke are regularly used both for positioning and for pressing from tube to tube as well as left and right, only in exceptional cases and with absolutely the same yield strength of the material across the entire metal sheet will the same parameters be used for the rotations or the press stroke used.

For this purpose, measuring devices for determining the current geometry are required, which can preferably be arranged in the form of measuring robots at the pipe end in the closing presses. According to the invention, the control is intended to provide a real-time output of the values calculated for displacement and pressure in order to implement stroke control that is dependent on the yield strength.

In an advantageous embodiment according to the invention, an even number of steps is selected in the molding press, so that the closing if necessary, can only be done by a single pressing step. For this purpose, as already known from the prior art, the first side should be manufactured with reduced immersion depths in order to achieve out-of-roundness, but the second side is then preferably molded in like a conventional tube, in particular a round tube. Since the last step of the second side, with an even total number of steps, does not lie in the middle of the tube, but laterally offset from it, it can be implemented geometrically without the support tube striking the forming blade too strongly. In this case, the end gap should preferably not be chosen too small in order to avoid undesired contact between the shaping sword and the support tube section.

In a further preferred embodiment of the invention, an asymmetrical preform with an even number of steps can also be produced in the JCO molding press, which previously could only be done with odd forming steps. As a result, the last forming step is no longer in the middle of the slotted tube and a collision between the edges of the slotted tube and the shaping sword can be prevented.

The advantage of the invention is that each tube can be reacted to individually in the closing process, i. This means that tailor-made rotations and press strokes are carried out in order to achieve the most uniform possible result when the sheet metal is formed into a slotted tube. As a result, better quality is achieved overall, since slotted tubes enter the tack welding machine with a more uniform shape and correspondingly more uniform tubes are produced in the tacking process. Differences in the slotted tube contour, which could occur when using rigid machine parameters, are minimized as far as possible. A multiple pressing, as was known and necessary from the prior art, can be avoided, so that the throughput of the device according to the invention can be increased. If the asymmetrical preform is produced in the molding press with an even number of steps, the closing can possibly also be reduced to a single step.

An advantageous measure according to the invention provides that the non-round preform is positioned in the finishing step before the application of the compressive force by rotating clockwise or counterclockwise. Depending on the positioning, the compressive force is thus introduced into the non-round preform to the left or right of the slot or gap.

According to a preferred proposal of the invention, the area that is less molded to the right of the center is rotated to an approximately 3 o'clock position and the area that is molded less to the left of the center is rotated to an approximately 9 o'clock position. With such a pre-positioned position of the non-circular preform on the supporting bodies of the lower tool, a maximum bending moment can be achieved for the final shaping.

The object on which the invention is based is achieved with a device in that means are provided for measuring the current geometry of the molded sheet metal plate, which are connected to a device for control, which is capable of online measured values for both the forming pressure and to provide the forming path in order to be able to carry out a stroke limit-dependent stroke control.

For forming the sheet metal sheet into an out-of-round preform and then forming it into the slotted tube, a lower tool, which is designed with reversible means in its direction of rotation, and a punch which can be acted upon from the outside against the positioned preform is preferably provided.

The finished slotted tube can thus be produced starting from the metal sheet on only one tube forming press or machine. The reversal of the direction of rotation allows the non-circular preform to be positioned exactly so that the pushing force comes into effect at the location of the action, namely on both sides of the slot. The bending bar of the pipe forming press can also be used to apply the compressive force from the outside to the preform. The press can optionally be converted with an additional stamp.

A preferred embodiment of the invention to increase the production output provides that at least one tube forming press producing a non-round preform is followed by a squeezing press which has the lower tool designed with reversible means in its direction of rotation and, as the upper tool, the punch which can be acted upon from the outside against the positioned non-round preform. In the production flow, the tube forming press, from which the non-round shape is ejected, is followed by a squeezing press, in which the non-circular preform supplied is formed into the finished slot tube in at least two successive steps, in each case to the right and left of the slot or gap , The non-circular preforming of the metal sheet can thus be carried out at a location that is independent of the final deformation to the slotted tube.

According to a proposal of the invention, the rotatable means of the lower tool are designed as two rotatably driven rollers arranged at a distance from one another. The reversal of the direction of rotation of the rolls allows the non-round preform to be positioned for the final shaping with optimized force application. The time course on the one hand in the preforming in the tube molding press and on the other hand the Completion in the squeeze press allows a downstream squeeze press to operate two tube forming presses.

An embodiment of the invention provides that the rotatable rollers are mounted with a suspension. The support of the non-circular preform on the lower tool of the compression press can be improved by a stationary support body provided between the rollers.

• 1 in schematischer Weise die Herstellung eines Schlitzrohres nach der Erfindung durch Erzeugung einer zunächst maßgeschneidert unrunden Vorform auf einer üblichen Rohrformpresse (a), die Herstellung eines fertigen Schlitzrohres aus der unrunden Vorform in einer der Rohrformpresse nachgeschalteten Zudrückpresse (b) und in einem Diagramm mit den Abmessungen wie zuvor in 1 c gezeigt das erfindungsgemäß hergestellte, fertige Schlitzrohr (c);
• 2 als Einzelheit der 1 die Zudrückpresse mit der in diese eingebrachten unrunden Vorform;
• 3A, 3B die Nach- bzw. Umformung der unrunden Vorform aus der Rohrformpresse in mindestens zwei Biegeschritten der Zudrückpresse, und zwar in einem ersten Biegeschritt durch Kraftbeaufschlagung der unrunden Vorform rechts neben dem Schlitz bzw. Spalt (3A) und nach Drehung der unrunden Vorform in einem zweiten Biegeschritt durch Kraftbeaufschlagung links neben dem Schlitz bzw. Spalt (3B), schematisch dargestellt; und
• 4A, 4B in schematischer Weise zwei Alternativen der Erzeugung einer unsymmetrischen Vorform mittels eines erfindungsgemäßen Verfahrens, welches eine grade Schrittzahl der Umformschritte nutzt.

Further features and details of the invention result from the claims and the following description of an embodiment of the invention shown in the drawings on the basis of two individual presses. Show it:

• 1 in a schematic manner the manufacture of a slotted tube according to the invention by producing an initially tailored non-circular preform on a conventional tube molding press (a), the manufacture of a finished slotted tube from the non-circular preform in a squeeze press downstream of the tube molding press ( b ) and in a diagram with the dimensions as previously in 1 c shown the finished slotted tube produced according to the invention ( c );
• 2 as a detail of the 1 the squeeze press with the non-circular preform introduced into it;
• 3A . 3B the reforming or reshaping of the non-circular preform from the tube molding press in at least two bending stages of the squeezing press, in a first bending step by applying force to the non-circular preform to the right of the slot or gap ( 3A) and after turning the non-circular preform in a second bending step by applying force to the left of the slot or gap ( 3B) , shown schematically; and
• 4A . 4B schematically two alternatives for the generation of an asymmetrical preform by means of a method according to the invention, which uses an even number of steps in the forming steps.

Forming a sheet of metal 3 to a slotted tube 104 , which has a significantly smaller slot or gap 111 exhibits (cf. 1c ), is after 1a on a tube forming press 1 carried out. However, this with the proviso that in each case to the right and left of the longitudinal axis of the bending sword 7 and thus next to the slot or gap 11 lying area of the metal sheet the bending step is carried out with a smaller bending of the metal sheet than in the other bending steps. There are thus defined two areas which are less molded in according to the respective bending step, as in 2 indicated, so that a preform that is deliberately non-circular, yet tailored for the final forming 13 is achieved.

The first step in the tube forming press 1 generated non-circular preform 13 after the conveying or pushing out of the tube forming press 1 a squeeze press downstream of the manufacturing process 14 fed as in 2 B shown. The squeeze press 14 has a lower tool 15 on, which consists of two spaced apart, reversible in their direction of rotation, as in 2 B indicated by the double arrows, driven rollers 16a . 16b and the distance between the roles 16a . 16b bridging, stationary support body 17 consists. The rotating rollers 16a . 16b can via a spring means 18 be supported (cf. 3 ). The lower tool 15 opposite is one with a stamp 19 trained upper tool 20 arranged. About the stamp 19 becomes the compressive force for producing the finished, largely circular slotted tube 104 from the outside to the non-circular preform 13 applied.

The non-circular preform 13 this is done via the rotatable rollers 16a . 16b positioned so that the right next to the slot or gap 11 lying, less molded area 12b is in a 3 o'clock position, as in 3 indicated by the dash-dotted, horizontal line.

The processes of this first pressing-bending step are in 3A shown, starting from left to right with the non-circular preform positioned 13 , the application of the pressing force by the stamp 19 and the stamp lifted off after the application of force 19 ,

The second press-bend step is - in the same order as before - in 3B illustrated. In order to optimize the bending moment, the preform, which is left out of round here, remains unchanged 13 positioned so that the left of the slot or gap 11 less molded area 12a occupies a 9 o'clock position. That by the stamp 19 now on this side of the preform 13 applied pressing force F (middle figure) brings the non-round preform 13 then in the final, largely circular shape of the finished slotted tube 104 with the significantly smaller slot or gap achieved in the process 111 (Fig.outside right).

The 4A and 4B show the production of asymmetrical preforms with straight ( 4B) or odd ( 4A) Step number. In 4A will with 21 Steps, ie 21 Forming processes, by means of the bending sword 7 on the metal sheet 3 , on side A a so-called potato shape and on side B has a round half-shape in the metal sheet 3 brought in. While the so-called potato shape on side A does not collide with the metal sheet 3 with the bending sword 7 causes, hits the metal sheet 3 on side B, in which an essentially round shape in the metal sheet 3 was brought to the bending sword 7 on. In 4B the advantage of producing an asymmetrical preform with 20 steps, thus an even number of steps, is illustrated. Neither on the side A , in a so-called potato shape in the metal sheet 3 was introduced, still in side B, by means of the forming sword 7 was formed into an essentially round preform, the sheet metal collided 3 with the forming sword 7 , since the last forming step along the dash-dotted line 21 , thus laterally offset to the center of the pipe. This can severely impact the slotted tube 4 to the sword 7 be avoided. As a result, the last forming step is no longer in the middle of the slotted tube 4 and a collision between the edges of the slit tube 4 and the sword 7 can be prevented.

LIST OF REFERENCE NUMBERS

1

Pipe forming press

2

Kantenanbiegung

3

metal sheet

4; 104

slotted tube

5a, 5b

support body

6

lower tool

7

bending rail

8th

mold

9

upper tool

10a, b

backstop

11; 111

Slot / gap

12a, b

less molded areas

13

out of round shape

14

Zudrückpresse

15

lower tool

16a, b

rotatable rollers

17

support body

18

spring means

19

stamp

20

upper tool

21

dash-dotted line

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 4215807 C2 [0004]
• EP 2529849 A2 [0006]

Claims (8)

Method for producing slotted tubes (4; 104) from sheet metal sheets (3), in particular thick sheet metal sheets, a sheet metal sheet being fed to a pipe forming press (1) in which it rests on a lower tool (6) by a lifting and lowering upper tool (9 ) is progressively formed by the application of a bending force to the slotted tube (4; 104) which has longitudinal edges opposite to a later longitudinal seam welding with a gap (11; 111), a slotted tube having an out-of-round preform (13) being produced by at least one In relation to the means given by the longitudinal axis of the upper tool (9) immersed in the progressively molded sheet metal plate (3), a molding is carried out on the left and right on the inside of the metal sheet (3), characterized in that the individual for each metal sheet Contour is determined, whereupon using a geometry model for the right and left S side of the slotted tube parameters for support tube positioning, in particular the angle of rotation and / or the length of rotation, as well as the online yield and evaluation of the pressure-displacement curve during the forming process, the yield point in each side of the sheet metal plate and then the dimension of the left in each case and the bending step acting on the inside of the sheet is determined on the right. Procedure according to Claim 1 , characterized in that the finished slotted tube is subsequently formed by the application of an external force to the non-circular preform in a targeted manner in the compression force which is previously formed on both sides of the center and which is smaller on both sides. Procedure according to Claim 1 or 2 , characterized in that the non-round preform (13) is positioned in the finishing stage before application of the pressing force (F) by turning clockwise or counterclockwise. Device for producing slotted pipes (4; 104) from sheet metal sheets (3), in particular thick sheet metal sheets, a sheet metal sheet being fed to a pipe forming press (1) in which it rests on a lower tool (6; 15) by a lifting and lowering upper tool (9) is progressively formed by applying a bending force to the slotted tube (4; 104) which has longitudinal edges opposite one another for later longitudinal seam welding with a gap (11; 111), in particular for carrying out the method according to one of the Claims 1 - 3 , wherein for forming the sheet metal plate (3) into a non-circular preform (13) and then for forming the slotted tube (104), a lower tool (15) designed with reversible means of rotation and a punch which can be acted upon from the outside against the positioned preform (13) (19) is provided, characterized in that means are provided for measuring the current geometry of the molded sheet metal plate (3), which are connected to a device for control, which is capable of online measured values for both the forming pressure and to provide the forming path in order to be able to carry out a stroke limit-dependent stroke control. Device after Claim 4 , characterized in that the control is designed to control each individual forming step of the metal sheet separately. Device after Claim 4 or 5 , characterized in that at least one tube forming press (1) producing a non-round preform (13) is followed by a squeezing press (14) which presses the lower tool (15), which is designed with reversible direction of rotation, and which acts as the upper tool (20) against the outside positioned non-round preform (13) has a pressurizable stamp (19). Plant according to one of the Claims 4 to 6 , characterized in that the lower tool (15) comprises two rotatably driven rollers (12a, 12b) arranged at a distance from one another and a support body (17) provided between the rollers (12a, 12b). Plant after Claim 7 , characterized in that the rollers (12a, 12b) are supported by a spring means (18).

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