EP2648861B1 - Methode and device for forming a pipe portion - Google Patents

Description

The invention relates to a method for producing a tubular container, in which a bottom is formed with an opening and with an inwardly projecting collar, according to the preamble of claim 1. Furthermore, the invention relates to a device for forming a workpiece, in particular a pipe section, according to the preamble of claim 15.

The generic device comprises a machine bed with a longitudinal axis, arranged along the longitudinal axis and rotatably driven work spindle, which is designed to receive the workpiece as a hollow shaft, a forming roller for forming the workpiece, wherein the forming roller along the longitudinal axis and along a transverse axis movable and to a pivot axis is rotatable.

A generic method and a generic device can be used in particular in the production of containers, in particular pressure vessels. Here, a container bottom is formed with an inwardly projecting collar. By inwardly projecting collar, the storage volume of the container can be increased while maintaining its overall height or overall width.

Widely used are containers, in particular pressure containers, with one or more outwardly projecting collars. In the collar, for example, a threaded connection can be introduced. A method for producing a pressure vessel with an outwardly projecting collar is for example in the DE 33 21 363 A1 described. The production of the bottom and the collar is carried out by means of a pressing method on a swivel molding press machine. A spinning roller is delivered along an arcuate path to a tubular workpiece around the container bottom to shape. A special shape of the spinning roller at the end of Zustellvorgangs an outwardly projecting bottleneck is formed.

A generic method is in the DE 196 07 010 C1 described. In this case, an axial end of a workpiece is introduced into a workpiece holder of a rotationally driven mold and shaped by pressing. By an axial feed movement of the mold and / or the workpiece, a pressing pressure is generated, which leads to a flow of the material of the workpiece. By means of a pin, the flowing material is directed inwards, so that a collapsed into the workpiece interior collar is formed.

The invention has for its object to improve a generic method and a generic device such that a particularly economical forming of a workpiece to form an inwardly projecting collar can be performed.

The object is achieved according to the invention by a method having the features of claim 1 and by a device having the features of claim 15. Preferred embodiments of the invention are specified in the respective dependent claims as well as in the following description and in the figures.

In a first aspect, the method according to the invention is characterized in that a tube section is set in rotation as the starting workpiece, that the tube section is retracted by means of a forming roller, wherein the bottom is formed by the retraction that an inwardly projecting material thickening is formed in the bottom and that in the region of the inwardly projecting material thickening an opening is introduced into the ground, wherein at least part of the inwardly projecting material thickening of the inwardly projecting collar is formed.

A first basic idea of the invention is to produce the floor with inwardly projecting or inverted collar substantially by a Einziehverfahren. For this purpose, according to the invention a pipe section by means of a forming roller, which may be referred to in particular as Einziehrolle retracted, so reduced the diameter of the pipe section.

As a starting workpiece or preform for the inventive method is a workpiece with a pipe section, so at least partially tubular workpiece. In particular, the tube section of the workpiece to be formed may have a cylindrical shape. But it is also possible that the pipe section at least partially a non-cylindrical shape, such as profiles, for example, with longitudinal and / or circumferential grooves, thickening, or conical and / or curved sections having.

A second basic idea of the invention is to form a bottom during or after drawing in with a material thickening or accumulation of material projecting into the workpiece interior and thus to form a thickened region of the bottom or a thickened pole cap. The bottom of the workpiece is thus thickened targeted in a defined area. The floor thus formed thus has a greater wall thickness in a region in which the opening is to be formed with the inwardly projecting collar, as the adjacent areas of the bottom, wherein the increased wall thickness by a defined, limited to a predetermined range, in the interior of the pipe section protruding material collection is formed. The accumulation of material or material thickening, which protrudes inwardly in the direction of the pipe section, forms the material for the collar to be formed.

According to the invention, the collar is formed in that an opening is made in the material accumulation in such a way that an annular collar or neck is formed by the remaining material of the material accumulation.

The floor may in particular be an upper or lower floor of a pressure vessel. Accordingly, the invention also relates to a method for manufacturing a container, in particular a pressure vessel, in which a bottom is formed with an opening and with an inwardly projecting collar. The bottom of the container can be made by a method of forming a pipe section. In this case, it is provided in particular that a remaining part of the pipe section or of the at least partially tubular workpiece forms a container wall of the container.

In a preferred embodiment of the invention, the retraction takes place by multiple pivoting movements of the forming roller along respectively different pivoting curves. The soil is thus formed by repeatedly overflowing the forming roller and thereby successively retracted further. During the pivoting movements of the forming roller, it is repeatedly moved along curved tracks whose radius is increasingly reduced in the direction of the initially open end of the pipe section obliquely inwards.

In an advantageous embodiment of the invention, it is provided that the bottom is closed before the introduction of the opening by the retraction, in particular gas-tight. From the pipe section is thus made by drawing first a workpiece shape with a closed bottom. For this purpose, the forming roller is preferably delivered so far inward, ie in the direction of an axis of rotation of the workpiece, and the tube section is drawn in so far that a contact of the material is produced in the region of the axis of rotation and thus a closed bottom is formed. The forming roller is thus so far fed radially when retracting until a closed bottom area is formed.

According to the invention, it is preferred that after closure of the bottom of the bottom for forming and / or shaping of the inwardly projecting material thickening is transformed. Additionally or alternatively to the reshaping of the floor after it has been closed, the thickening of the material can be at least partially formed even before the closing of the floor.

A simple possibility of producing the inwardly projecting material thickening is that to form the inwardly projecting material thickening material is moved from an outer region of the pipe section and / or the soil in a central region of the soil. Under the outside area is to be understood in particular a radially outer region of the pipe section and / or the bottom. In particular, the center region refers to a region of the bottom about an axis of rotation of the pipe section or of the workpiece. The displacement of the material can be carried out in particular by a curved delivery of the forming roller.

Preferably, the inwardly projecting frusto-conical material thickening is at least partially made during retraction. For this purpose, it is provided in particular that the pivoting curves, along which the forming roller are moved for retraction, are adapted so that a desired shape is achieved with a predetermined wall thickness profile of the floor.

The inwardly projecting material thickening can be produced in a particularly advantageous manner by first forming an outwardly protruding thickening of the material and then subsequently converting the material thickening projecting outwards into the inwardly projecting material thickening. The outwardly protruding material thickening can be easily produced by an appropriate choice of the pivoting curves of the forming roller. The outwardly protruding material thickening can then be converted by forming into an inwardly projecting material thickening.

Advantageously, the outwardly protruding material thickening is already at least partially produced during the drawing. This can be achieved by a suitable shape of the pivoting curves along which the forming roll is moved for drawing. For this purpose, the pivoting curves can in particular be designed so that a pivoting radius of the forming roller is increased in the region of the material accumulation to be formed.

The deformation of the outward material thickening in the inwardly projecting material thickening can be advantageously effected by an axial advancement of a forming tool. In principle, the forming tool may be a different tool from the forming roller. However, it is particularly preferred that the forming roller is used as the forming tool, with which also the drawing takes place. This is a particularly economical method. This is delivered axially, so that material of the soil flows axially inwards and so the inwardly projecting, frusto-conical material thickening is formed, which has a thickness in the axial direction, which at least the 2-, 4- or 5 times the original wall thickness.

Furthermore, it is preferred that the soil for the enrichment of material in the region of the inwardly projecting material thickening is pre-stamped from the outside. A Such pre-embossing can in particular be effected by impressing material from outside, for example by means of a lance, in particular a truncated cone plant. This creates a depression in the pre-embossed region on the outside of the bottom and material is displaced into the interior of the workpiece, pipe section or container. By pre-stamping a particularly targeted enrichment of the material can be effected.

After the pre-embossing, it may be advantageous to heat the pre-embossed area to ensure that with further material displacement in the pre-embossment or depression a gas-tight bottom remains homogeneous structure. Upon further forming further material is moved in the area of the pre-stamping and thus closed the previously formed recess with material.

A particularly clean forming can be achieved according to the invention in that the forming roller is perpendicular to a reshaping workpiece contour of the workpiece or the pipe section during the forming. The forming roller preferably has a cylindrical compression geometry which is engaged with the workpiece contour during the forming process. To avoid wrinkling, the forming movements and the roll geometry of the forming roller are designed so that the deformation takes place largely only under compressive stress at minimum tensile stress.

In a preferred embodiment of the invention, it is provided that the opening is introduced by means of a cutting process, in particular by drilling and / or milling.

In a further preferred embodiment, the opening is produced by thermal cutting, for example by hole-cutting or hole-cutting welding.

It is particularly preferred if a further accumulation of material in the interior of the pipe section or of the container is brought about by the introduction of the opening. For this purpose, it is preferred that the opening is introduced by impressions, for example by means of a lance, or by flow forming. By the impressions or the flow forming, which also as flow drilling or drill drilling can be referred to, material of the inwardly projecting material thickening is displaced radially outward and thus increases the collar and stabilized.

It may also be advantageous for a depression to be first introduced into the soil, for example by being pressed in by means of a truncated cone plant, and the depression being opened by mechanical processing, for example drilling, in a further method step. This embodiment is particularly advantageous in combination with the pre-embossing of the thickened region of the soil.

The deformation is preferably carried out in a warm state, in particular at about 900 to 1000 ° C. The heating can be done either on the forming machine itself, for example by gas burners or inductively, or outside the forming machine, for example by a Anwärmofen or by induction. Preferably, the temperature of the workpiece during the deformation by means of a temperature measuring device is determined, and possible heat losses are compensated by a heat supply device, in particular a gas burner.

According to the method of the invention, it is particularly preferred that a blank, on which the collar is formed with the opening, is set in rotation, and that an outer circumference of the blank is axially formed against a spinning chuck to form a tube section, to form a tube section, to which the collar is directed.

A first basic idea here is that the production of the collar takes place before the production of the pipe section. It is therefore possible in a simple manner to form a tubular workpiece with an inwardly directed collar from a blank on which a hub-shaped collar or neck has been formed in a first step.

A second idea is to not reshape the outer periphery of the blank from the collar or neck, but toward the collar or neck to form an inwardly directed, tubular collar of a tubular container.

In a preferred embodiment, the collar is formed on the blank by spin forming. The production of the collar by pressing / spinning is an economical process.

The round blank may preferably be a sheet metal blank.

To carry out the method, it is preferred that a device for forming a workpiece is used, which has a spinning chuck with an axial recess for the collar. The collar can be inserted into the recess of the spinning chuck and the workpiece then be formed by means of a forming roller to the spinning chuck.

A particularly economical production of a container with two open bottoms, ie two bottoms, in which an inwardly projecting collar is present, can be achieved by a combination of the method according to one of claims 1 to 12 with the method according to one of claims 13 or 14 , In this case, in particular first with the method according to one of claims 13 or 14 from a blank with a collar, a tubular body having a first bottom and an inwardly projecting collar can be produced. The shaping of the second floor can then take place by the method according to one of claims 1 to 12. The starting workpiece according to claim 1 can therefore be produced by the method according to claim 13.

The device according to the invention is characterized in that a hole-producing tool is provided in order to introduce an opening along the longitudinal axis into the workpiece when the workpiece is clamped. The production of the opening, which may be in particular a hole or a depression, can be done in the same clamping as the Einziehvorgang.

In the device according to the invention it is preferred that the forming roller is mounted so that a forming force can be applied to a arranged in the region of the longitudinal axis of material thickening of the workpiece by a translational movement of the forming roller along the longitudinal axis. For this purpose, in particular a longitudinal support displaceably mounted along the longitudinal axis can be provided, on which the forming roller is mounted directly or indirectly. To apply the Forming force, it is advantageous if a feed force is introduced symmetrically to the longitudinal axis in the longitudinal support.

Fig. 1

eine schematische Darstellung eines Einziehvorgangs eines rohrförmigen Werkstücks;

Fig. 2

eine schematische Darstellung eines Einziehvorgangs eines rohrförmigen Werkstücks mit verdickter Öffnungswand;

Fig. 3

eine Vorrichtung zur Durchführung des erfindungsgemäßen Verfahrens;

Figuren 4a bis 4h

eine erste Ausführungsform des erfindungsgemäßen Verfahrens;

Figuren 5a bis 5e

eine zweite Ausführungsform des erfindungsgemäßen Verfahrens;

Figuren 6a bis 6f

eine dritte Ausführungsform des erfindungsgemäßen Verfahrens;

Figuren 7a bis 7e

eine vierte Ausführungsform des erfindungsgemäßen Verfahrens;

Fig. 8

eine Umformrolle bei der Umformung;

Fig. 9

ein nach dem erfindungsgemäßen Verfahren hergestellter erster Behälter;

Fig. 10

ein Abschnitt eines nach dem erfindungsgemäßen Verfahren hergestellten weiteren Behälters und

Fig. 11

eine weitere Ausführungsform einer erfindungsgemäßen Vorrichtung und des erfindungsgemäßen Verfahrens.

The invention will be further described by means of preferred embodiments, which are schematically illustrated in the accompanying drawings. In the drawings shows:

Fig. 1

a schematic representation of a Einziehvorgangs a tubular workpiece;

Fig. 2

a schematic representation of a Einziehvorgangs a tubular workpiece with thickened opening wall;

Fig. 3

an apparatus for carrying out the method according to the invention;

FIGS. 4a to 4h

a first embodiment of the method according to the invention;

FIGS. 5a to 5e

a second embodiment of the method according to the invention;

FIGS. 6a to 6f

a third embodiment of the method according to the invention;

FIGS. 7a to 7e

a fourth embodiment of the method according to the invention;

Fig. 8

a forming roller during forming;

Fig. 9

a first container produced by the method according to the invention;

Fig. 10

a section of a further container produced by the process according to the invention and

Fig. 11

a further embodiment of a device according to the invention and the method according to the invention.

The Figures 1 and 2 show an embodiment of the method according to the invention using the example of a Einziehvorgangs for producing a bottom 18 or a polar cap for a container 28, in particular a pressure vessel. The work piece 10 may be, for example, a welded or seamless pipe. It is also possible for the workpiece 10 to be produced from a blank in a preceding working step, for example by pressing / spinning rollers. The workpiece 10 preferably contains a metal, in particular stainless steel.

The pipe section 12 of the workpiece 10 has a reshaped longitudinal section 14, which is formed into a bottom 18. The longitudinal section 14 or the pipe section 12 is, in particular, an axial end section of the workpiece 10.

The workpiece 10, which may also be referred to as a preform, is formed or drawn in by means of a forming roller 52, in particular a pull-in roller. For this purpose, the workpiece 10 is driven to rotate with the tube section 12 about a rotation axis 11. The deformation of the workpiece 10 is then carried out with a rotating workpiece 10. Basically, instead of the one forming roller 52, a plurality of forming rollers can be used.

The reshaping of the length section 14 to the bottom 18 takes place in several successive overflows of the forming roller 52. Here, the cylindrical length portion 14 is formed by the forming roller 52 to smaller diameters out, that is, it will be a workpiece contour with decreasing diameter in the axial direction and in axial and / or radial direction of increasing wall thickness. The movement of the forming roller 52 takes place such that a desired profile of the longitudinal section 14 or the bottom 18 results. The longitudinal section 14 of the tube section 12 is reshaped so far that the bottom 18 is closed completely and in particular gas-tight.

Before, during and / or after closing the bottom 18, a thickening of the material 22 is formed on the bottom 18. The material thickening 22 is formed such that an inwardly projecting material thickening 24 is formed. The result is a locally thickened bottom portion in the region of the axis of rotation 11. Nach forming the material thickening 22, 24, an opening 20 is introduced into the thickened region of the bottom 18.

In Fig. 1 the deformation is shown using the example of a tube with a wall thickness which is constant in the region of the length section 14 to be formed. This can be a welded or a seamless pipe. Fig. 2 shows a deformation of a workpiece 10, which has a thickened opening wall, so a thickened length portion 15. By the thickened length portion 15 additional material for the formation of the bottom 18 and in particular the material thickening 22 is provided. The length section 14 has, in addition to the thickened region 15 with a constant wall thickness, a transition region 16 with a transition slope.

For carrying out the method, a forming device or forming machine 40, in particular drawing-in machine, as in Fig. 3 shown used. The forming machine 40 comprises a machine bed 42, which is preferably designed as an inclined bed. The forming machine 40 further comprises a headstock 44, in which a work spindle 46 is rotatably mounted about a longitudinal or machine axis 47. The work spindle 46 is rotatably driven by means of a spindle drive 48 and is designed as a hollow shaft to receive the workpiece 10 herein. For clamping the workpiece 10 is on the work spindle 46, a chuck 50 is arranged.

For forming the workpiece 10, the forming machine 40 has a forming roller 52, which is rotatably mounted about a rotation axis 53. The forming roller 52 is mounted on the machine bed 42 such that a translational movement along the longitudinal axis 47, a translational movement along a transverse axis 63 and a pivoting movement 30 about a pivot axis 65 is possible. The forming roller 52 is mounted for this purpose on a pivot support 64 which is rotatable about the pivot axis 65. The pivot support 64 is in turn constructed on a longitudinal support 60 which is displaceable along the longitudinal axis 47 of the forming machine 40. Furthermore, a transverse support 62 is provided, which allows a displacement of the forming roller 52 along the transverse axis 63. The forming roller 52 is also adjustable with the pivot support 64.

The forming roller 52 is mounted on a forming housing 54. At the forming housing 54 Anwärmbrenner 58 is arranged, which is adjustable with the forming housing 54. The forming housing 54 is in particular attached to the pivot support 64. With the Anwärmbrenner 58, the workpiece 10 can be heated when the forming roller 52 is in engagement with the workpiece 10.

The combination of longitudinal support 60, transverse support 62 and pivot support 64, a movement of the forming roller 52 along arbitrary trajectories is possible. The longitudinal support 60 allows a pure translational movement of the forming roller 52 along the longitudinal axis 47. By a delivery of the forming roller 52 along the longitudinal axis 47, ie in an axial direction of movement 32, material can be moved from an outer region of the bottom 18 in an interior of the workpiece 10 be, in particular to transform an outwardly protruding material thickening 23 in an inwardly projecting material thickening 24, as will be described in detail below.

The forming machine 40 further has a hole-forming device 70, which comprises a hole-forming tool 72, namely a cutting torch 73. Alternatively, a lance 74 and / or a flow former 75 could be arranged. The hole forming tool 72 is disposed on a pivot arm 78 which is pivotable about a pivot axis 79 to pivot the hole forming tool 72 from a rest position to a working position. The pivoting of the pivot arm 78 can be effected by means of a lifting cylinder 80.

Furthermore, the forming machine 40 comprises a preforming device 86 with a forming or preforming tool 88 for preforming or pre-embossing the workpiece 10. The preforming tool 88 in this example is a lance 74, in particular a truncated cone plant. Alternatively, the flow former 75 or the lance 74 could be arranged. The preform tool 88 is movable on a preform support 90 along the longitudinal axis 47 and along the transverse axis 63. By displacing the preforming tool 88 along the transverse axis 63, the preforming tool 88 can be moved from a rest position to a working position. By moving along the longitudinal axis 47, the preforming tool 88 can be delivered toward the bottom 18 of the tool 10 to pre-form or pre-stamp the bottom 18 of the tool 10.

For post-processing of the workpiece 10, in particular the opening 20, a post-processing tool 92 is provided, which may in particular comprise a drill, a chamfer, a chopper, a tap and / or a flaring tool.

Finally, the forming machine 40 has a temperature measuring device 98 for determining a temperature, in particular a temperature in the region of a forming zone of the workpiece 10. For heating and / or reheating an already preheated workpiece 10, a heat supply device is further provided.

To carry out the method, the workpiece 10 to be formed is introduced into the work spindle 46 designed as a hollow shaft and clamped by means of the chuck 50. The clamping of the workpiece 10 in the work spindle 46 is carried out such that the reshaped longitudinal portion 14 of the workpiece 10 protrudes from the work spindle 46 and the chuck 50. Preferably, an additional axial region protrudes from the chuck 50 in addition to the length section 14 to be reshaped. An axial end of the chuck 50 is in the Figures 1 and 2 designated by the reference numeral 51.

Further variants and embodiments of the method according to the invention are described below, in particular with reference to FIGS FIGS. 4 to 8 , described.

A first embodiment of the method according to the invention is in the FIGS. 4a to 4h shown. After clamping the workpiece 10 in the work spindle 46, the workpiece 10 is offset by means of the spindle drive 48 about its axis of rotation 11 in rotation and deformed by means of the forming roller 52. The rotation axis 11 coincides with the longitudinal axis 47 of the forming machine 40. By forming a gas-tight bottom 18 is produced.

Before and / or after the closure of the bottom 18, further material is displaced from an outer region of the pipe section 12 and / or the bottom 18 inwards, in the direction of a center region 19 of the bottom 18, in order to thicken this region, Fig. 4a , The central region 19 is located in particular in the region of the axis of rotation 11 of the workpiece 10 or the longitudinal axis 47 of the forming machine 40. By the displacement of material in the direction of the axis of rotation 11 and the accumulation of material in the central region 19, an outwardly protruding material accumulation or material thickening 23 is first formed.

The outwardly projecting material thickening 23 is formed in a further process step in an inwardly projecting material thickening 24. For this purpose, the forming roller 52 is delivered axially along the longitudinal axis 47 or the axis of rotation 11. As a result, material is pressed into the interior of the container 28 or the pipe section 12, Fig. 4b , The method steps 4a and 4b can, as in the FIGS. 4c to 4f shown, repeated until the inwardly projecting material thickening 24 has a desired volume and / or a desired shape. The molding and thickening of the bottom 18 thus takes place in several draw-in overflows.

To ensure a gas-tight closure of the bottom 18, the bottom 18 between the individual pivoting movements of the forming roller 52 can be reheated. This can be done for example with a Anwärmbrenner 58 and / or a hole welding torch.

The number of pivoting movements and the amount of delivery after each pivoting movement are preferably preselected in a control. In the last pivoting movements, the outer surface of the bottom 18 can be additionally smoothed and / or a shoulder for a protective cap can be formed.

The inwardly projecting material thickening 24 is opened, preferably directly after drawing in and thickening. This can be done for example by means of a hole welding torch, Fig. 4g , By introducing an opening 20, an annular, in particular tubular, collar 26 is formed around the opening 20. The collar 26 protrudes inwards into the interior of the workpiece or the interior of the container, ie, it is inverted into the interior of the workpiece or the interior of the container.

The manufactured opening 20 can be machined in a further operation, for example, to make a connection for a valve and / or to introduce a thread in the collar 20, Fig. 4h ,

Another embodiment of the method according to the invention is shown schematically in FIGS FIGS. 5a to 5e shown. Unlike in the FIGS. 4a to 4h illustrated method, a recess is first introduced into the material accumulation 22, 24, Fig. 5d , The introduction of the depression takes place by means of a Aufweitwerkzeugs, in particular a Kegelstumpflanze 74. By the recess, a closed collar 25 is first formed, which is inverted inside. Subsequently, the recess is drilled to a through hole, so that the opening 20 is made, Fig. 5e , The preparation of the recess by means of the truncated cone 74 is preferably carried out in the same setting as the previous forming. By introducing the opening 20 of the open, inwardly inverted collar 26 is formed.

The truncated cone 74 has a frusto-conical axial end portion. To create the recess in the bottom 18, the truncated cone 74 is pressed axially, in particular without rotational movement, into the bottom 18 or the material thickening 22, 24 formed therein. At the axial end of the truncated cone 74, a blunt, in particular rounded pressing region is provided.

The FIGS. 6a to 6f show a further process variant of the method according to the invention. In this case, the thickened region of the bottom 18, that is to say the material thickening 22, is pre-embossed when it is pulled in at least one intermediate step, Fig. 6c , By pre-embossing, for example by means of a truncated cone, material is moved into an inner region of the tube section 12 and the container 28 and enriched there.

After the pre-embossing further material is moved into the center of the bottom 18 and thus closed the previously formed pre-embossment with material, Fig. 6d , Subsequently, in a further process step, analogous to Fig. 5d made, for example by means of a truncated cone, a funnel-shaped depression, Fig. 6e , The funnel-shaped depression forms a closed collar 25, which in a further method step analogously Fig. 5e can be opened and machined, Fig. 6f ,

Another variant of the method is in the FIGS. 7a to 7e shown. The opening of the inwardly projecting material thickening 24 to form the inwardly projecting Collar 26 is effected by means of a hole-forming tool 72 in the form of a widening tool, for example a lance 74, a drill bit and / or a flow former 75, FIGS. 7a to 7d , In the flow forming, the opening 20 is produced in a chipless forming process. By means of the flow former 75, the produced opening 20 can be subsequently extended by a transverse movement of the flow former 75, Fig. 7d ,

The flow former 75 has a conical tip and an adjoining cylindrical portion which determines the diameter of the resulting bore or opening 20. The machined material is not machined, but displaced by the force of the flow former 75 and resulting frictional heat. As a result, the material of the inwardly projecting material thickening 24 is radially displaced and thus forms a particularly stable collar 26. As in the method variants described above, the opening 20 can then be machined.

In an advantageous embodiment, the forming roller 52 has one or more forming edges 54, which perform the actual forming. Next is a forming and guiding section 55, in particular for guiding and guiding the formed material. The forming and guiding section 55 lies flat against the material contour during the forming process. In the design of the pivoting movements, it is advantageous if the forming roller 52 is perpendicular to a current workpiece contour during the forming, as in Fig. 8 shown. In particular, this means that at least one of the forming sections 54 of the forming roller 52 is perpendicular to the workpiece contour to be formed. The forming and guiding section 55 may precede or follow the forming section 54 during forming, so that the formed material slides along the forming and guiding section 55.

The forming and guiding portion 55 has a substantially planar contact surface, which can also be used for the axial displacement of material for forming the outwardly protruding material thickening 23 in the inwardly projecting material thickening 24.

Fig. 9 shows a container 28 produced according to the inventive method, in particular pressure vessel. The container 28 has a cylindrical portion 29 and a bottom 18 at opposite ends of the cylindrical portion 29, respectively. The bottoms 18 were each produced by means of the method according to the invention and each have an opening 20 with an inwardly projecting collar 26. Due to the manufacturing process of the inwardly projecting collar 26, the collar 26 tapers from the bottom 18 in the axial direction inwards. The bottoms 18 of the container 28 are each configured as flat bottoms.

Fig. 10 shows a portion of a corresponding container 28 with a circular bottom. Alternatively to the in the FIGS. 9 and 10 shown bottom shapes can be produced with the method according to the invention also any other shaped soils.

Fig. 11 shows a further embodiment of a forming device 40. The device according to Fig. 11 is in particular for carrying out the preferred method steps according to the dependent claim 13, in which a blank 8 is used as the starting workpiece, is provided.

The device 40 has a spinning chuck 45, which is designed tubular and can also be referred to as a spinning mandrel. At one axial end of the spinning chuck 45 is a central receiving opening 38 for further collar 26 'of the ronde-shaped workpiece 10.

Furthermore, the device 40 comprises a pressure element 49. The pressure element 49 is mounted axially displaceably in a housing 36 and serves to press the workpiece 10 axially against the spinning chuck 45 and thus to clamp between the spinning chuck 45 and the pressing element 49.

The housing 36 is designed as a forming die 37. The forming die 37 is axially movable relative to the spinning chuck 45 and relative to the pressing element 49. By an axial movement between forming die 37 and spinning mandrel 45, the workpiece 10 can be formed, in particular deep drawing and / or pressing. In this way, a bottom 18 can be formed with a desired contour. The forming die 37 has for this purpose an axial Umformausnehmung 39.

Finally, the device 40 comprises one or more forming rollers 52 with which a cylindrical wall region or pipe section 12 can be formed after deep drawing or pressing of the bottom by spin forming. The forming roller 52 is mounted on a roller holder 56.

Furthermore, in Fig. 11 several steps of a preferred embodiment of the method according to the invention shown. Fig. 11 a shows a blank 8 or a blank-shaped workpiece 10, which serves as the starting workpiece. The workpiece 10 comprises a ronde-shaped portion 6 with a rotation axis 11. The workpiece 10 further comprises a tubular portion 7, which forms a tubular further collar 26 '. The further collar 26 'extends along the axis of rotation 11 of the workpiece 10.

To produce a tubular workpiece 10, in particular a container, the workpiece 10 is clamped between the spinning chuck 45 and the pressing element 49 or between the spinning chuck 45 and the forming die 37.

The clamping takes place in such a way that the further collar 26 'extends in the direction of the spinning chuck 45 and in particular projects into the receiving opening 38 of the spinning chuck 45.

The ronde-shaped workpiece 10 is then preformed or deep-drawn by an axial displacement of the forming die 37 relative to the spinning chuck 45, as in FIG Fig. 11b shown. In this case, the pressure element 49 can be moved with the forming die 37 at the same time, wherein the spinning chuck 45 is preferably fixed. By the pressing member 49 and / or the forming die 37, a bottom 18 is formed in a central region of the workpiece 10.

After forming the bottom 18, the forming die 37 is axially withdrawn from the spinning chuck 45 and thus removed from the work area, Fig. 11c ,

The spinning chuck 45, the pressing element 49 and the workpiece 10 are then rotated about the longitudinal axis 47 in rotation. The workpiece 10 is reshaped with the forming roller 52, wherein an outer region of the workpiece 10 to a cylindrical shape or a cladding region, ie the pipe section 12, is formed, as in Fig. 11d shown. The outer region of the workpiece 10 is for this purpose in Formed in the direction of the further collar 26 ', so that an inwardly projecting, tubular further collar 26' is formed, which extends substantially parallel to the pipe section 12, so the container wall. The forming roller 52 moves for this purpose along the longitudinal axis 47 in the direction in which the further collar 26 'extends from the bottom 18.

For an improved forming, during the processing with the at least one forming roller 52, a post or intermediate heating can be provided.

Claims (16)

1. Method for producing a pipe-shaped container, in which a base (18) with an opening (20) and with an inward-projecting collar (26) is provided,

   - wherein as basic workpiece a pipe section (12) is set into rotation,

   characterized in that

   - the pipe section (12) is necked in by means of a forming roller (52), wherein the base (18) is provided through the necking-in process,

   - in that an inward-projecting material thickening (24) is formed into the base (18) and

   - in that in the area of the inward-projecting material thickening (24) an opening (20) is introduced into the base (18), wherein the inward-projecting collar (26) is provided by at least a part of the inward-projecting material thickening (24).
2. Method according to claim 1,
   characterized in that
   the necking-in process is effected through several pivoting movements of the forming roller (52) along different pivot curves in each case.
3. Method according to claim 1 or 2,
   characterized in that
   the base (18) is closed through the necking-in process prior to the introduction of the opening (20).
4. Method according to claim 3,
   characterized in that
   after closing the base (18), the said base (18) is formed in order to provide and/or shape the inward-projecting material thickening (24).
5. Method according to any one of claims 1 to 4,
   characterized in that
   to provide the inward-projecting material thickening (24) material is shifted from an external area of the pipe section (12) and/or the base (18) to a central area (19) of the base (18).
6. Method according to any one of claims 1 to 5,
   characterized in that
   the inward-projecting material thickening (24) is produced at least partially during the necking-in process.
7. Method according to any one of claims 1 to 6,
   characterized in that

   - initially an outward-projecting material thickening (23) is formed and

   - in that subsequently the outward-projecting material thickening (23) is formed into the inward-projecting material thickening (24).
8. Method according to claim 7,
   characterized in that
   the forming of the outward-projecting material thickening (23) into the inward-projecting material thickening (24) is effected through an axial feeding of a forming tool.
9. Method according to any one of claims 1 to 8,
   characterized in that
   for the accumulation of material in the area of the inward-projecting material thickening (24) the base (18) is pre-stamped from the outside.
10. Method according to any one of claims 1 to 9,
    characterized in that
    during the forming process the forming roller (52) is positioned perpendicularly to a workpiece contour of the pipe section (12) to be formed.
11. Method according to any one of claims 1 to 10,
    characterized in that
    the opening (20) is introduced by means of a cutting method.
12. Method according to any one of claims 1 to 11,
    characterized in that
    the opening (20) is introduced through displacement drilling.
13. Method according to any one of claims 1 to 12,
    characterized in that

    - to provide the pipe section (12) a circular blank (8) is used, on which a further collar (26') with a further opening is designed, and

    - the circular blank (8) is set into rotation and, for the purpose of providing the pipe section (12), an outer circumference of the circular blank (8) is formed axially against a spinning chuck (45) towards a side, to which the further collar (26') is directed.
14. Method according to claim 13,
    characterized in that
    the further collar (26') is designed on the circular blank (8) through spinning/flow forming.
15. Device for forming a workpiece (10) according to the method according to any one of claims 1 to 12, with

    - a machine bed (42) with a longitudinal axis (47),

    - a work spindle (46), arranged along the longitudinal axis (47) and capable of being driven in a rotating manner, which is designed as a hollow shaft for accommodating the workpiece (10),

    - a forming roller (52) for forming the workpiece (10), wherein the forming roller (52) is movable along the longitudinal axis (47) and along a transverse axis (63) and rotatable about a pivot axis (65),

    characterized in that
    a hole producing tool (72) is provided to introduce an opening (20) along the longitudinal axis (47) into the workpiece (10) while the said workpiece (10) is clamped.
16. Device according to claim 15,
    characterized in that
    the forming roller (52) is supported such that through a translational movement of the forming roller (52) along the longitudinal axis (47) a forming force can be applied to a material thickening (22) of the workpiece (10) arranged in the area of the longitudinal axis (47).

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