EP1283333B1 - Method of manufacturing an exhaust gas catalyst - Google Patents

Abstract

The production of an exhaust gas catalytic converter comprising a catalyst in a housing with two end connectors comprises taking a tube (30) long enough to make two housings, indenting the tube in the middle, cutting the tube at the indentation (36) to make two workpieces, charging each piece with catalyst, and indenting the charging end of each piece.

Description

The invention relates to a method for producing a Catalytic converter according to the preamble of claim 1.

Catalytic converters of the type mentioned are under used in other vehicles in the purification of exhaust gases. The catalytic converter is usually made of a metal housing formed in which a catalyst insert arranged is. The catalyst used is usually a ceramic body, a so-called monolith used by a Varied flow channels and on its surface coated with a catalytically active substance is. Often, the catalyst insert has a padding wadding on, with the ceramic body wrapped in the housing is used.

From DE 197 34 198 A1 is a process for the preparation a catalytic converter known in which from a sheet first deep-drawn the housing of the catalytic converter is, at the same time the first port of the catalytic converter is formed on the housing. Subsequently the catalyst insert is inserted into the housing and the second connection piece is retracted by rolling.

JP 2000179334 describes a method and a device for producing a catalytic converter with a Housing with two connecting pieces, as well as one in the housing arranged catalyst insert. The catalyst insert is inserted into a housing forming tube, and the Ends of the pipe are used to make the connecting pieces shaped by chipless forming. The tube is in his Length dimensioned so that a double workpiece are manufactured can, and an intermediate section between the two Ends is formed. Finally, the pipe is in range the reformed intermediate section separated and formed two individual workpieces, which after insertion of the Catalyst insert are molded at its insertion end.

DE 197 23 939 A1 discloses a method for the production an exhaust gas catalyst in which as starting material a pipe is used, one of which is an open end first is retracted by non-cutting forming. Subsequently, will in the still open insertion end of the tube of the catalyst insert introduced. After assembly of the catalyst insert becomes the still open introductory to forming the second Connecting piece of the catalytic converter by non-cutting forming moved in.

The method known from DE 197 23 939 A1 records already characterized by high productivity. The housing the catalytic converter is made of comparatively thin sheets is made, usually sheet thicknesses of about 1.5 mm. In this case, when forming the connecting piece on Housing the risk of wrinkling due to excessive tangential Compressive stresses. Furthermore, the housing of catalytic converters often made of hard-to-mold materials, especially made of stainless steels, which also tend to wrinkle.

To avoid this, is in this known method the tube from the inside with the help of an internal mandrel when pulling supported the connecting piece. Despite this measure can the chipless forming in this known method often performed only in stages, to avoid wrinkling. When using a Flow-forming process for retracting the connection piece is So a variety of roll overflows required to to form the connecting pieces. This results in a relatively long production time.

When forming the second connection piece on the housing There is also the problem that the connection piece usually not formed against an internal mandrel can. Consequently, one is compared with the molding the first connecting piece still larger number of forming steps required, with even lower forming speeds must be carried out to the formation to avoid wrinkles.

It is an object of the invention to provide a particularly efficient method for producing a catalytic converter.

The invention solves the problem by a method with the Features according to claim 1. Advantageous developments of inventive method will become apparent from the following Description, the drawing and the dependent Claims.

In the method according to the invention, the tube is in his Length so that from the tube a double workpiece can be made. In a first process step becomes an intermediate portion of the pipe between the two Retracted ends, whereby the double workpiece formed becomes. In this way are on two workpieces at the same time two connecting pieces are formed, whereby the manufacturing time compared with the known methods significantly reduced. At the same time, the formation of wrinkles avoided when drawing in the intermediate section of the tube, because the pipe material on both sides of the intermediate section the pipe material in the forming area of the intermediate section supports. This will cause the kink stability of the pipe material in the forming area compared to those during forming acting tangential compressive stresses so far increases that wrinkling in the intermediate section during Forming is prevented. By the fact that in this Process step, a wrinkling on the pipe almost is excluded, the tube can be compared with a the known method much higher forming speed be confiscated in the intermediate section. When feeding can the contour of the connecting piece in a single Shaping be shaped, resulting in an additional Shortening of the production time results.

Subsequently, the pipe is pulled in the area of the Intermediate section separated, with the two individual workpieces be formed from the double workpiece. After this Inserting the catalyst inserts into the workpieces, the Inserting the catalyst inserts may be before or after Separating the intermediate section will be made every single piece of work at its introductory part to form the second connecting piece retracted.

In a preferred process variant of the invention Method is the intermediate section of the tube symmetrical formed between its ends, so that the after separation formed individual workpieces at least show approximately identical dimensions. In this way It is possible to use two tubes simultaneously to produce identical individual workpieces.

To accelerate the overall manufacturing process, it is furthermore advantageous, the pipe immediately after drawing the intermediate section to separate, since the insertion of the Catalyst inserts in the individual workpieces is simplified and feeding the importers of the individual workpieces separate processing stations simultaneously can. Furthermore, it is in this process variant of Advantage, when the retraction of the intermediate section and the Separating the double workpiece into the two individual workpieces in a single clamping, so that the pipe not stretched after drawing in the intermediate section and in a subsequent processing device for Disconnect must be re-clamped. This results a particularly high manufacturing accuracy, since the various Processing steps on one and the same machine can be performed.

The forming of the tube takes place in a particularly preferred Process variant with the help of at least two forming rollers. By using the forming rollers results on the one hand, the advantage that with appropriate adjustment the forming rollers a correspondingly large design freedom in the molding in particular of the pipe transitions is given in the connection piece. on the other hand is a particularly gentle by the use of forming rollers Pulling in of the connecting pieces on the pipe is achieved. at This variant of the method is in particular the use of three forming rollers advantageous, evenly over the circumference of the pipe are distributed, as through this Arrange the forming forces that lead to a bending of the Pipe could lead during forming of the forming rollers taken each other and thus balanced become.

Especially when using pipes with low wall thickness is also proposed, when retracting the intermediate section the pipe from the inside of the pipe support the intermediate section with even higher forming speeds ausformieren, as a buckling of the Pipe is almost excluded by the inner support. To support the intermediate portion is preferably the Use of an internal mandrel proposed in the pipe is introduced. In a particularly preferred process variant In both ends of the tube are two inner mandrels introduced in the area of the intermediate section to each other come to the plant. The use of an internal mandrel also has the advantage that with appropriate design the outer contour of the inner mandrel the inner contour of the Pipe defined to be manufactured housing of the catalytic converter can be formed.

It is also proposed that the introductory part of the Pipe when pulling the connection piece from the inside to support it, even in this process step to avoid unwanted wrinkling. Also with this Process variant may preferably for supporting the pipe an internal spike used in the introductory of the tube introduced during insertion of the second connecting piece becomes.

In a preferred process variant of the invention Manufacturing process is used to retract the insertion end at least one forming roll used against an at least partially conical Thorn is formed. By an axial and radial feed movement The forming roller is the workpiece to be reshaped each between a section of the conical Dorns and the forming roll out.

In a particularly advantageous development of this method variant the conical mandrel is synchronized with the feed movement of the forming roller moved axially, so that the edge of the workpiece area to be reshaped supported and temporarily between the mandrel and the forming roller is guided. As a result, wrinkles can be avoided or incurred Wrinkles are rolled smoothly.

Furthermore, when using a mandrel, it is proposed to use a mandrel with a cylindrical section, when pulling the tube to form a cylindrical Pipe section, for example for the formation of the connecting piece, leads.

In a particularly preferred variant of the method is also proposed, when pulling the tube the retracted pipe sections to the finished connection piece to mold. This allows for subsequent processing steps dispensed with the finishing of the connecting piece become.

As catalytic converters over a wide variety of cross-sectional shapes is also proposed, not only in cross-section to use circular tubes as starting material but according to the final cross section of the to be produced Housing of the catalytic converter to use pipes in the Cross section are not rotationally symmetric. So be in particular in cross-section oval or elliptical tubes used as starting material.

Furthermore, it may be necessary for catalytic converters be that the connecting pieces offset from the longitudinal axis of the Housing run. To also such catalytic converters to manufacture with the method according to the invention, is in a particularly preferred process variant proposed, the tube during forming around a rotation axis to rotate, with the tube parallel with its longitudinal axis offset from the axis of rotation runs. The connecting pieces of the housing then become concentric about the axis of rotation formed of the pipe, so that the connecting pieces after retraction of the tube offset to the longitudinal axis of the tube are formed on this.

Alternatively, it is also possible, the tube with its longitudinal axis at a predetermined angle inclined to the axis of rotation let go, so that when feeding of the pipe connecting pipe at an angle inclined to the longitudinal axis of the tube extending at this formed are.

It is also proposed to train the trainees Make the connecting piece in such a way that it fits with its Symmetry axes offset from each other.

In a particularly preferred variant of the invention Method are used to reshape the pipe at the same time used several forming rollers, wherein the forming rollers radially and optionally simultaneously also axially be delivered. The forming rollers can in their outer contour It should be designed so that by forming formed outer profile of the tube in its shape of the final shape of the catalytic converter corresponds. At the same time by the use of forming rollers extremely gentle and economical manufacturing of catalytic converters possible.

So when using at least one forming roll for forming the tube also tubes with non-rotationally symmetric Cross-sectional shapes can be formed is further proposed, the forming roller during retraction of the Tube between a maximum and a minimum delivery position to adjust radially. This procedure for non-cutting production is not rotationally symmetrical parts basically known.

After the method is provided, to form a defined Deviation from rotational symmetry the forming roll during a single turn of the pipe between the maximum and the minimum delivery position radially to Adjust, wherein the radial adjustment of the forming roller during a single revolution of the rotation angle of the Pipe depends.

To deliver the forming roll is in this process in particular uses an electronically controllable actuator, controlled by an electronic control unit is, which is a Zustellweg for the forming roller the rotation angle of the pipe, given geometric data of Pipe and of the exhaust gas catalyst to be formed (nominal data) and a correction factor determined.

Should also pipes with the inventive method higher-strength materials are also reformed, it is also proposed before and possibly also during forming of the pipe, the pipe to a temperature above the To heat the recrystallization temperature of the pipe material, whereby the pipe material the forming lower resistance forces opposes.

Fig. 1

eine geschnittene Seitenansicht eines Abgaskatalysators;

Fig. 2

eine geschnittene Seitenansicht eines Rohrs beim Ausformen eines Doppelwerkstücks zur Fertigung zweier Gehäuse zweier Abgaskatalysatoren;

Fig. 3

eine geschnittene Seitenansicht, in der die Fertigung eines zweiten Anschlussstutzens eines der Gehäuse gezeigt ist;

Fig. 4

eine geschnittene Seitenansicht, in der die Fertigung des zweiten Anschlussstutzens eines der Gehäuse unter Verwendung eines zylindrischen Innendorns gezeigt ist;

Fig. 5

eine geschnittene Seitenansicht, in der die Fertigung des zweiten Anschlussstutzens eines der Gehäuse unter Verwendung eines konischen Innendorns gezeigt ist;

Fig. 6

eine geschnittene Seitenansicht eines nicht rotationssymmetrischen Rohrs nach dem Ausformen zu einem Doppelwerkstück;

Fig. 7

eine geschnittene Vorderansicht des Rohrs nach Fig. 6;

Fig. 8

eine geschnittene Vorderansicht eines im Querschnitt ovalen Rohrs nach dem Ausformen der Anschlussstutzen;

Fig. 9

eine Seitenansicht, in der das Ausformen des Doppelwerkstücks nach einer zweiten Verfahrensvariante gezeigt ist, bei der die Anschlussstutzen versetzt zur Längsachse des Rohrs an diesem ausgeformt werden;

Fig. 10

eine Vorderansicht, in der die verschiedenen Verfahrensschritte beim Ausformen des Doppelwerkstücks gezeigt sind;

Fig. 11

eine geschnittene Seitenansicht eines Abgaskatalysators mit ovalem Querschnitt, der nach dem Verfahren nach Fig. 9 gefertigt worden ist;

Fig. 12

eine Vorderansicht des Abgaskatalysators nach Fig. 11; und

Fig. 13

eine geschnittene Seitenansicht, in der eine dritte Verfahrensvariante zum Fertigen eines Abgaskatalysators gezeigt ist.

The method according to the invention is explained in more detail below with reference to three variants with reference to the drawing. Show:

Fig. 1

a sectional side view of an exhaust gas catalyst;

Fig. 2

a sectional side view of a tube during the molding of a double workpiece for the production of two housings of two catalytic converters;

Fig. 3

a sectional side view showing the production of a second connection piece of one of the housing is shown;

Fig. 4

a sectional side view showing the manufacture of the second connecting piece of one of the housings using a cylindrical inner mandrel;

Fig. 5

a sectional side view showing the manufacture of the second connection piece of one of the housings using a conical inner mandrel;

Fig. 6

a sectional side view of a non-rotationally symmetrical tube after molding into a double workpiece;

Fig. 7

a sectional front view of the tube of Fig. 6;

Fig. 8

a sectional front view of a cross-sectionally oval tube after the molding of the connecting piece;

Fig. 9

a side view in which the molding of the double workpiece according to a second variant of the method is shown, in which the connecting pieces are offset from the longitudinal axis of the tube formed on this;

Fig. 10

a front view showing the various steps in the molding of the double workpiece are shown;

Fig. 11

a sectional side view of an exhaust catalyst with oval cross-section, which has been manufactured by the method of FIG. 9;

Fig. 12

a front view of the catalytic converter of FIG. 11; and

Fig. 13

a sectional side view, in which a third variant of the method for manufacturing a catalytic converter is shown.

In Fig. 1 is a sectional side view of an exhaust gas catalyst 10, for example, in motor vehicles used for cleaning exhaust gases. The catalytic converter 10 has a housing 12 which is made of a stainless Steel is made. In the housing 12 is a catalyst insert 14 recorded. The catalyst insert 14 is formed of a ceramic monolyte 16, in which a Variety of flow channels are formed, through which the Exhaust gas flows, and its surface with a catalytic active substance is coated. To the ceramic monolith 16, a padding mat 18 is laid, which is the ceramic monolith 16 completely encloses and this in the housing 12 in a defined position. The housing portion 20, in the catalyst insert 14 is received goes to everyone its ends to form a transition contour 22 respectively in a connecting piece 24 via. The connecting pieces 24 serve as an inlet or outlet for the catalytic converter 10, wherein the individual exhaust pipes, not shown the exhaust system to the connecting piece 24 in known Be releasably secured manner.

In Fig. 2 is a first variant of the invention Process for producing the catalytic converter shown in Fig. 1 10 is shown. For the production of the catalytic converter 10 is a pipe 30 made of a stainless Steel used, from which the housing 12 of the catalytic converter 10 formed by the method according to the invention becomes. The tube 30 is dimensioned in its length, that made of the pipe a total of two catalytic converters 10 can be, as will be explained later.

The tube 30 is first with its two ends 32 and 34th in the spindles (not shown) of a flow-forming machine used. Subsequently, an intermediate portion 36, the formed symmetrically between the two ends 32 and 34 is retracted by means of a first forming roller 38. The Forming roller 38 is continuously fed radially, while at the same time the tube 30 about an axis of rotation R in Rotation is offset. The outer contour 40 of the forming roller 38 is designed so that through the outer contour 40th the forming roller 38, the transition contours 22 and the connecting pieces 24 two housing 12 are made, the with their connecting pieces 24 merge into each other. there is the hollow cylindrical shape of the connecting piece 24th formed by a cylindrical peripheral surface 42, the symmetrically between the end faces of the forming roller 38 at the outer contour 40 is shown.

By this method, a double workpiece 44 is formed, at the same time the ends 32 of two housing 12th each formed in its final shape. there Due to the shape of the tube 30, wrinkling will occur prevented in the intermediate section 36, since the pipe material in Forming region of the intermediate portion 36 of the pipe material supported on both sides of the intermediate section 36, whereby the kinking stability in the forming area comparatively is high.

After forming the intermediate portion 36, the double workpiece 44 by means of a cutting roller (not shown) divided into two individual workpieces 46, the following be fed to a separate processing.

In a development of the method variant described above becomes the tube 30 during the molding of the intermediate section 36 additionally supported from the inside. To this Purpose be in the two open ends 32 and 34 of the Pipe 30 Innendorne 48 introduced in the area of Intermediate portion 36 with their end faces to each other Plant come. The inner mandrels 48 are designed in this way that the outer contour 47 of the later inner contour of the Tube 30 corresponds. After positioning the inner mandrels 48, the forming roller 38 is radially delivered and the tube 30 fed with the method step described above. After retraction, the inner mandrels 48 are out again the tube 30 pulled out and the formed double workpiece 44 using a cutting roller in the two individual workpieces 46 separated.

The inner mandrels 48 may have a larger diameter paragraph 49, where the pipe ends 32, 34 come to rest. When moving the Innendorne 48 can be a compression take place for accumulation of material in the intermediate section 36. Vice versa is also a dilution by appropriate delivery the forming roller 38 possible.

After separating the tube 30 is in each individual workpiece 46 first of the wrapped with the mat 18 Keramikmonolyt 16 through the still undeformed end 34 of the tube 30th introduced into the tube 30. Subsequently, the tube 30th with its deformed end in the spindle (not shown) used a further flow-forming machine.

As shown in FIG. 3, after the tensioning of the tube 30 in the Spindle the still undeformed end 34 through which the catalyst insert 14 was introduced, with the help of a second Forming roller 50 to the transition contour 22 and the second Connecting piece 24 formed. Again, the outer contour 52 of the forming roller 50 having a cylindrical peripheral surface 54 provided so that the connecting piece 24 finished is formed without the subsequent further processing the connecting piece 24 is required.

In Fig. 4 is a modified process step in Section shown in which when retracting the second end 34 of the tube 30 additionally an internal mandrel 56 is used, which is inserted into the open end 34 of the tube 30 during retraction becomes. The inner mandrel 56 has a cylindrical Support surface 58 and a radially projecting from this Bund 60 on. With the help of the cylindrical support surface 58 the inner contour of the connecting piece 24 is defined formed while the collar 60 an axial flow of the Pipe material limited.

In Fig. 5 is an alternative embodiment of the Process step for pulling in the second end 34 of the Tube 30 shown in section. In this process variant becomes the second end 34 by means of a third forming roller 62 reshaped, in the opposite of the two previously described Variants on the outer peripheral surface of the Pressure roller 62 only a radially encircling forming edge 64th is trained. Furthermore, in this embodiment a conical mandrel 66 is used, which is a cone-shaped Support surface 68 and a subsequent to this cylindrical support surface 70 has. The cylindrical Support surface 70 is on the front side of the conical Dorns 66 provided and goes into the widening cone-shaped Support surface 68 via.

To reshape the second end 34 of the tube 30, the conical Dorn 66 with its cylindrical support surface 70 in the open second end 34 of the tube 30 is inserted. Subsequently the third forming roller 62 is delivered radially and simultaneously moved axially. In the same way the conical mandrel 66 synchronized with the feed motion the Umformrolle 62 axially moved, wherein the fold avoidance the workpiece area to be reshaped at least temporarily between the forming edge 64 of the third forming roller 62 and a surface portion of the tapered support surface 68 of the conical mandrel 66 is guided, as shown in FIG. 5 shows. The feed movements between the forming roller 62 and the conical mandrel 66 are continued as long as until the forming roller 62 in the region of the cylindrical Support surface 70 passes. From this point on, the forming roll becomes 62 only axially with respect to the conical mandrel 66 adjusted, whereby the high cylindrical connecting piece 24 is formed as the dashed lines in Fig. 5 shows.

The ones described above with reference to FIGS. 2 to 5 Process variants can also be used for forming tubes 30a and 30b with non-rotationally symmetrical cross sections can be used, as shown in Fig. 6 to 8 are. Thus, the tube 30a shown in Figs. 6 and 7 has a cross-sectionally O-shaped shape. That in Fig. 8 On the other hand, the tube 30b shown has an oval shape, such as it is customary in particular in catalytic converters 10.

For retracting the connecting piece 24 is in these tubes 30a and 30b with non-rotationally symmetrical cross sections a method for non-cutting forming not rotationally symmetric Parts used. In this process the forming roller 38, 50 or 62 is delivered controlled, so that from the initially not rotationally symmetrical pipe cross-section the hollow cylindrical connecting piece 24 is formed while at the same time the transition contour 22 arises.

FIGS. 9 and 10 show a process variant of the invention Shown method. In this process variant is the tube 30 with its longitudinal axis L to the amount X offset to the rotation axis R in the flow-forming machine (not shown) used. Subsequently is the intermediate portion 36 on the pipe 30 by a total formed three forming rollers 38, while the tube 30th rotates about the rotation axis R. The forming rollers 38 are thereby delivered radially with different amount, such as Fig. 10 shows, whereby the retracted intermediate portion 36 off-axis with respect to the longitudinal axis L of the tube 30 at this is formed, as Fig. 9 shows. Subsequently, will the resulting double workpiece 44 in the previously described Way divided into two individual workpieces 46, in each individual workpiece 46, the catalyst insert 14 is used and the still undeformed end 34 of each individual workpiece 46 in a similar manner to the catalytic converter 10a reshaped.

FIGS. 11 and 12 show an exhaust gas catalytic converter 10b. the one with the method described above from a cross-section oval tube 30b has been made. In this Catalytic converter 10b became the single workpiece 46 for molding the second port 24 but offset in parallel used in the flow-forming machine, so the two finished connecting piece 24 offset from each other and offset from the longitudinal axis of the tube 30b formed on this are.

FIG. 13 shows a third variant of the method in which the Tube 30 with its longitudinal axis L under a predetermined Angle α inclined to the rotation axis R in the spindle 72nd the flow-forming machine used and the intermediate section 36 has been formed. Subsequently, the thus formed Double workpiece 44 separated in the manner described above, into the resulting individual workpieces 46 catalyst inserts 14 used and the still open ends 34 of Individual workpieces 46 retracted. Again, this will be the case to be formed individual workpiece 46 with its longitudinal axis L below a predetermined angle α inclined to the axis of rotation R of the spindle 72 inserted into this. The second end 34 is then reshaped with the aid of a forming roller 74, that the resulting when retracting the second end 34 Connecting piece 24 inclined at the angle α to the longitudinal axis L of the tube 30 and the individual workpiece 46th is formed at this running.

Claims (17)

1. Method of manufacturing an exhaust gas catalyst (10), which has a housing (12) with two connecting branches (24) as well as a catalyst insert (14) arranged in the housing (12), which

   is inserted into a pipe (30) forming the housing (12), which ends (32, 34) are drawnin by non-cutting reshaping for creating the connecting branches (24), wherein

   the pipe (30) has such a length that a double work-piece (44) can be made from it,

   the pipe (30) is drawn-in at an inter-section (36) among both ends (32, 34),

   characterized in that

   the drawing-in of the pipe (30) takes place by radially feed motion of at least one reshaping roller (38), which is provided with an outer profile which corresponds to the outer profile in the inter-section of the pipe (30) created by reshaping according to the final shape of the exhaust gas catalyst (10),

   the pipe (30) is cut off in the area of the drawn-in inter-section (36), wherein two single workpieces (46) are built and

   each single work-piece (46) is drawn-in at its insert-end (34) after the inserting of the catalyst insert(14).
2. Method according to claim 1,
   characterized in that
   the inter-section (36) of the pipe (30) is formed-out symmetrically between the pipe's ends (32, 34).
3. Method according to claim 1 or 2,
   characterized in that

   the pipe (30) is cut off immediately after the drawing-in of the inter-section (36), particularly by means of a cutting roller and

   the drawing-in of the inter-section (36) and the cutting off is taken place particularly in one clamping.
4. Method according to claim 1, 2 or 3,
   characterized in that
   the reshaping of the pipe (30) takes place by the means of at least two reshaping rollers (38, 50, 62).
5. Method according to anyone of claims 1 to 4,
   characterized in that

   the inter-section (36) is supported during the drawing-in from the inner side of the pipe (30) and

   for the support of the inter-section (36) it is inserted at least one inner mandril (48) into the pipe (30).
6. Method according to anyone of claims 1 to 5,
   characterized in that

   at least the edge of the insert end (34) of the pipe (30) is supported during drawing-in from the inner side of the pipe (30) and

   that for supporting is used a mandril (56, 66), which is inserted in the insert end (34).
7. Method according to claim 6,
   characterized in that
   the insert end (34) is pressed during the drawing-in against the mandril (66), which is designed conically at least in sections by means of at least one reshaping roller (62).
8. Method according to claim 7,
   characterized in that
   the conical mandril (66) is moved axially synchronised with the feed motion of the reshaping roller (62), so that the area of the work-piece which must be reshaped is supported and is led among the conical mandril (66) and the reshaping roller (52) at least occasionally.
9. Method according to anyone of claims 5 to 8,
   characterized in that
   the mandril (48, 56, 66) has a cylindrical section (42, 54, 70), which leads to the building of a cylindrical pipe section (24) during the drawing-in of the pipe (30).
10. Method according to anyone of the previous claims,
    characterized in that
    during the drawing-in of the pipe (30) is formed-out the pipe sections being drawn-in to the finished connecting branches (24).
11. Method according to anyone of the previous claims,
    characterized in that
    a pipe (30) is used, which is rotationally non-symmetric, in particular is oval.
12. Method according to anyone of the previous claims,
    characterized in that

    the pipe (30) rotates during the reshaping around a rotation axis (R),

    the pipe's (30) longitudinal axis (L) has a parallel offset in relation to the rotation axis (R),

    the connecting branches (24) created during the drawing-in of the pipe (30) around the rotation axis (R) are formed-out at said pipes displaced to the longitudinal axis (L) of the pipe (30).
13. Method according to anyone of the claims 1 to 11,
    characterized in that

    the pipe (30) during the reshaping rotates around a rotation axis (R),

    the pipe (30) with its longitudinal axis (L) is running under a determinated angle (α) inclined to the rotation axis (R) and

    the connecting branches (24) formed during the drawing-in of the pipe (30) around the rotation axis (R) are formed-out at said pipe (30) running under the angle (α) inclined to the longitudinal axis (L) of the pipe (30).
14. Method according to anyone of the previous claims,
    characterized in that
    the drawn-in connecting branches (24) run with their symmetric axes displaced to each other.
15. Method according to anyone of the previous claims,
    characterized in that
    for reshaping of the pipe (30) are used at the same time several reshaping rollers (38, 50, 62).
16. Method according to anyone of the previous claims,
    characterized in that

    for reshaping of the pipe (30) is used at least one reshaping roller (38, 50, 62)

    for the forming-out of a defined divergence from the rotation symmetry the reshaping roller (38, 50, 62) is adjusted radially during one singular revolution of the pipe (30) between a maximal and a minimal feed position,

    the radially adjusting of the reshaping roller (38, 50, 62) during one singular revolution depends on the rotation angle of the pipe (30).
17. Method according to anyone of the previous claims,
    characterized in that
    the pipe (30) is warmed up before the reshaping to a temperature upwards the recristallisation temperature of the pipe material.

Images