EP2529849A2 - Device and method for manufacturing slot pipes made of sheet panels - Google Patents

Abstract

The method involves supplying a sheet panel (3) to a pipe forming press (1) in which the sheet panel is molded to a slot pipe through application of bending force, where the slot pipe is provided with longitudinal edges. The slot pipe is manufactured with an irregular blank mold while a small molding of the sheet panel is carried out in a bending stage caused at an inner side of the sheet panel. The manufactured slot pipe is removed through application of pressing force in smaller areas formed in the center, where the pressing force acts outwardly on the blank mold. An independent claim is also included for a device for manufacturing cylindrical slot pipes from thick sheet panels.

Description

The invention relates to a method for producing slotted tubes from sheet metal plates, in particular thick metal sheets, wherein a metal sheet is fed to a tube forming press in which it rests on a lower tool of a raised and lowered upper tool by applying a bending force progressively to the later Längsnahtschweißung With a gap opposite longitudinal edges having slot tube is formed. Furthermore, the invention relates to a device for carrying out the method.

One of the most widely used methods for producing sheet metal tubes is the tube molding process with progressive molding or bending steps on tube molding presses. A pipe forming or tube bending press has usually in a base frame one of two laterally spaced juxtaposed support or bending bodies existing lower tool and a vertically engageable from above against the lower die, carried by a raisable and lowerable bending bar, over the entire length the metal sheet extending upper tool with which a bending force can be applied to the resting on the lower die metal sheet.

For the production of a pipe or large pipe according to the progressive molding process several successive steps are required. The Metal sheet is pre-bent at the longitudinal edges in a first step, usually in a separate edge banding press. The pre-bending of the longitudinal edges is carried out so that the tube radius in the deformation of the slot tube in the region of the later seam, where the longitudinal edges of the bent to the tube sheet metal plate face each other for Längsnahtverschweißung with a gap is uniformly formed. The thus pre-bent metal sheet is then inserted into the pipe-forming press and subjected there to the actual bending process. In this case, a bending force is applied to the metal sheet by depressing the press upper part, which sets a deformation of the metal sheet under the action of the bending load value and carried by this upper mold. This procedure is repeated several times until the metal sheet has been converted to the slot pipe.

By the DE 42 15 807 C2 has become known in a frame design tube bending or tube forming press has become known. The trained as a bending tool sword is guided vertically in side uprights of the frame. This upper bending tool is attached to piston-cylinder units to a small extent gimbal movable and rests on this against the upper frame cross member. The support bodies of the lower bending tool are carried by a table which also supports piston-cylinder units coaxial with the upper piston-cylinder units. The counteracting piston-cylinder units are to prevent bending of the table, even if the lower frame crossbar should bend under the working load of the press. For this purpose, individual piston-cylinder units are subjected to more or less pressure.

A very problematic in the progressive molding process has a significantly influenced by the sword width, especially in thick-walled tubes, for example, 40 mm remaining, large residual gap of the slot of about 130 to 170 mm and also shown stresses in the slot tube. A Large slit width requires high closing forces in the tack welding device, and because of the high stresses in the stapled as well as residual stresses in the finished welded pipe there is a risk of a rupturing tack or weld. When recognized too large slot widths remedy is created by the fact that experienced machine operators have closed by repeated manual actuation of the tube forming press the slot as far as possible. This procedure is not only time consuming with correspondingly reduced throughput, but continue to perform not with reproducible good quality.

The invention is therefore an object of the invention to provide a method and a system of the type mentioned without the disadvantages mentioned, especially in thick-walled and small in diameter, for example, about 800 mm, tubes in a simple way the production of circular cylindrical slotted tubes with reproducible quality create.

This object is achieved by a method according to the invention in that first a slot tube is produced with a non-circular preform by at least in a relative to the dipping of the longitudinal axis of the progressively formed metal sheet upper tool center respectively left and right on the inside of the metal sheet acting bending step is compared to the other Biezogen lower indentation is made, and that thereafter by applying an externally on the non-circular preform each targeted in the previously on both sides of the middle of small molded areas impacting Zudrückkraft the finished slot tube is formed.

Thus, by deliberately creating an initially tailored non-circular preform with partially reduced indentation, for example with a bend of 12 ° instead of a bend of 24 °, a largely circular slot tube geometry with a minimal slot can be formed. Due to the lower molded areas Namely, the requirement is created that then the externally applied Zudrückkraft then in these lower molded areas significantly more sustainable than in the other pipe sections and as a result leads to a largely circular slotted pipe with desired tightly closed gap. Unlike a dependency on the experience of the machine operator, the reproducibility is improved and the throughput is increased while the quality remains the same.

Both for partial non-preforming as well as for final or final molding two bending steps or two Zudrückvorgänge may be sufficient, even in the final molding with each of the left and right of the gap or slot applied Zudrückkraft.

An advantageous measure according to the invention provides that the non-circular preform is positioned in the finishing step before applying the Zudrückkraft by rotation in a clockwise or counterclockwise direction. Depending on the positioning, the compression force is thus introduced to the left or right of the slot or gap in the non-circular preform.

According to a preferred proposal of the invention, the area of the lower half formed on the right side of the center is turned to an approximately 3 o'clock position and the area of the lower left of the center is turned to an approximately 9 o'clock position. With such a prepositioned position of the non-round preform on the support bodies of the lower tool, a maximum bending moment can be achieved for final shaping.

The object underlying the invention is achieved with a device that is provided for forming the metal sheet to a non-circular preform and then reshaping to the slotted tube with reversible in their rotation means formed lower tool and externally acted upon against the positioned preform punch.

The finished slot 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 in such a way that the compressive force acts at the point of action, namely on both sides of the slot. It can readily be used to apply the Zudrückkraft from the outside to the preform, the bending rate of the tube forming press. Optionally, the press can be converted with a Zudrückstempel.

An embodiment of the invention which is preferred for increasing the production output provides that at least one tube forming press producing a noncircular preform is followed by a pressing press, which has the lower tool formed with means reversible in its direction of rotation and, as upper tool, the punch which can be acted on from the outside against the positioned non-circular preform. In the production flow, the tube forming press, from which the non-circular shape is ejected, thus closes a pressing press, in which the supplied non-circular preform is formed into the finished slot tube at least in two successive steps, respectively 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 independent of the final deformation of the slot pipe.

The rotatable means of the lower tool are formed according to a proposal of the invention as two spaced-apart, rotatably driven rollers. Reversing the direction of rotation of the rollers makes it possible to position the non-circular preform for final forming with optimized force introduction. The time course on the one hand in the preforming in the tube forming press and on the other hand the completion in the Zudrückpresse allows that a downstream Zudrückpresse can serve two tube forming presses.

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

Fig. 1

in schematischer Weise die schrittweise Einformung (a) einer Blechtafel zu einem Schlitzrohr (b) auf einer zum Stand der Technik zählenden Rohrformpresse und in einem Diagramm (c) an einem vorgegebenen Abmessungsbeispiel das fertige Schlitzrohr;

Fig. 2

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 Fig. 1c gezeigt das erfindungsgemäß hergestellte, fertige Schlitzrohr (c);

Fig. 3

als Einzelheit der Fig. 2 die Zudrückpresse mit der in diese eingebrachten unrunden Vorform; und

Fig. 4A, 4B

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 (Fig. 4A) und nach Drehung der unrunden Vorform in einem zweiten Biegeschritt durch Kraftbeaufschlagung links neben dem Schlitz bzw. Spalt (Fig. 4B), schematisch dargestellt.

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

Fig. 1

schematically the stepwise molding (a) of a metal sheet to a slit pipe (b) on a prior art tubular molding press and in a diagram (c) on a given dimension example, the finished slotted tube;

Fig. 2

schematically the production of a slot pipe according to the invention by producing a first custom-made non-round preform on a conventional pipe molding press (a), the production of a finished slotted tube from the non-round preform in a tube forming press downstream Zudrückpresse (b) and in a diagram with the dimensions as before in Fig. 1c show the finished slotted tube (c) produced according to the invention;

Fig. 3

as a detail of Fig. 2 the squeezing press with the non-round preform introduced into it; and

Fig. 4A, 4B

the reshaping or deformation of the non-circular preform from the tube forming press in at least two bending steps of the pressing press, in a first bending step by application of force to the non-round preform to the right of the slot or gap ( Fig. 4A ) and after rotation of the non-round preform in a second bending step by applying force to the left of the slot or gap ( Fig. 4B ), shown schematically.

On as such a well-known tube forming press 1 is after Fig. 1 one on their long sides with edge bends 2 (see. Fig. 3 ) provided sheet metal plate 3 gradually to a finished slotted tube 4 a - or reshaped. The metal sheet 3 is placed on a two spaced-apart support body 5a, 5b having lower tool 6, wherein the forming force of a bending spring 7 with a mounted on his leading front end mold 8, raised and lowered upper tool 9 is applied. The metal sheet 3 to be formed or formed is guided by two lateral counter-supports 10a, 10b, of which the counter-holder 10a is linearly adjustable and nachschiebt the required for a next Einformschritt sheet metal section. The finished slot pipe 4, as in Fig. 1c illustrates, has a large slot or gap 11, the welding to a closed, longitudinally welded pipe, as shown in dashed lines in Fig. 1c shown, extremely difficult.

The transformation of a metal sheet 3 to a slit pipe 104, which has a much smaller slit or gap 111 (see. Fig. 2c ) will, after Fig. 2a carried out on a tube forming press 1 as described above. However, this with the proviso that in each case right and left of the longitudinal axis of the bending bar value 7 and thus adjacent to the slot or gap 11 area of the metal sheet of the bending step is carried out with a smaller bending of the metal sheet than in the remaining bending steps. There are thus defined two areas corresponding to the respective bending step less molded areas, as in Fig. 3 indicated, so that a targeted non-round, yet tailored for the preforming preform 13 is achieved.

The non-circular preform 13 thus produced in a first stage in the tube-forming press 1 is fed from the tube-forming press 1 to a pressure-feeding press 14 which is connected downstream in the production process after the conveying out or pushing Fig. 2b shown. The Zudrückpresse 14 has a lower tool 15, which consists of two spaced-apart, reversible in their direction of rotation, as in Fig. 2b indicated by the double arrows, driven rollers 16a, 16b and a distance between the rollers 16a, 16b bridging, stationary support body 17 is made. The rotatable rollers 16a, 16b can be supported supported by a spring means 18 (see. Fig. 3 ). The lower tool 15 opposite a formed with a punch 19 upper tool 20 is arranged. About the punch 19, the Zudrückkraft for producing the finished, largely circular slot tube 104 is applied from the outside to the non-circular preform 13.

The non-circular preform 13 is positioned over the rotatable rollers 16a, 16b so that the less molded portion 12b located to the right of the slit 11 is in a 3 o'clock position as in FIG Fig. 3 indicated by the dot-dashed, horizontal line.

The processes of this first Zudrück bending step are in Fig. 4A illustrated, starting from left to right with the positioned non-circular preform 13, the application of the drawing force by the punch 19 and the lifted after the force stamp 19th

The second press bending step is - in the same sequence as before - in Fig. 4B illustrated. In order to optimize the bending moment, the preform 13, which is still non-circular in its left half, has been positioned such that the area 12a, which is formed less to the left of the slot or gap 11, assumes a 9 o'clock position. The applied by the punch 19 now on this side of the preform 13 Zudrückkraft F (middle figure) brings the non-circular preform 13 then in the final, largely circular shape of the finished slot tube 104 with the achieved thereby, much smaller slit or gap 111 (Fig. Right outside).

LIST OF REFERENCE NUMBERS

1

Pipe forming press

2

Kantenanbiegung

3

metal sheet

4; 104

slotted tube

5a, b

support body

6

lower tool

7

bending rail

8th

mold

9

Upper tool (punch)

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

F

Zudrückkraft

Claims (7)

Method for producing slotted tubes (4; 104) from sheet metal plates (3), in particular thick sheet metal plates, whereby a sheet metal plate is fed to a tube forming press (1) in which it rests on a lower tool (6) resting on a raised and lowered upper tool (9 ) is formed by applying a bending force progressively to the laterally seam welding with a gap (11, 111) opposite longitudinal edges having slot tube (4; 104) is formed,
characterized,
in that a slotted tube having a non-round preform (13) is first produced by means, at least in each case, for each of the left and right on the inner side of the metal sheet (3) given in relation to the upper tool (9) dipping into the progressively formed metal sheet (3). 3) acting bending step is performed with respect to the other bending steps lower indentation, and that thereafter by applying a from the outside on the non-circular preform (13) in each case specifically in the previously on both sides of the center of small molded regions (12a, 12b) impacting Zudrückkraft (F ) the finished slotted tube (104) is formed. Method according to claim 1,
characterized,
that the non-circular preform (13) in the finishing stage before applying the Zudrückkraft (F) is positioned by rotation in a clockwise or counterclockwise direction. Method according to claim 2,
characterized,
in that the portion (12b) of the lower half formed on the right side of the center is turned to an approximately 3 o'clock position and the lower left portion of the center (12a) is rotated to an approximately 9 o'clock position. Device for producing slotted tubes (4; 104) from sheet metal plates (3), in particular thick sheet metal plates, whereby a sheet metal plate is fed to a tube forming press (1) in which it rests on a lower tool (6; 15) resting on a raised and lowered upper tool (9) is formed by applying a bending force progressively to the laterally seam welding with a gap (11; 111) opposite longitudinal edges having slot tube (4; 104) is formed, in particular for performing the method according to claim 1,
characterized,
in that for forming the metal sheet (3) into a non-circular preform (13) and then forming it into the slotted tube (104), a lower tool (15) designed to be reversible in its direction of rotation and a punch (13) to be acted upon externally against the positioned preform (13) 19) is provided. Device according to claim 4,
characterized,
in that at least one tube forming press (1) producing a noncircular preform (13) is followed by a pressing press (14), which comprises the lower tool (15) formed with means reversible in its direction of rotation and, as an upper tool (20), the outer preform positioned against the (FIG. 13) acted upon punch (19). Plant according to claim 4 or 5,
characterized,
in that the lower tool (15) comprises two spaced-apart, rotatably driven rollers (12a, 12b) and a support body (17) provided between the rollers (12a, 12b). Plant according to claim 6,
characterized,
in that the rollers (12a, 12b) are mounted via a spring means (18).

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