DE102018115695A1 - Device for producing a cylindrical or cone-shaped, circumferentially closed tubular body - Google Patents

Abstract

The invention relates to a device (10) for producing a tubular body (12) which is in the shape of a cylinder jacket or a cone jacket and is circumferentially closed, in particular an exhaust pipe, an exhaust gas muffler housing jacket and / or an exhaust gas cleaning device housing jacket. The device (10) has a receiving space (14) for a cylindrical jacket-shaped or conical jacket-shaped tubular body preform (18) having a circumferential gap (16). Furthermore, it comprises a locking mechanism for closing the peripheral gap (16) of the tubular body preform (18), which has at least two separate locking segments (24), each of the locking segments (24) being assigned an individual drive unit (26), so that the locking segments (24) can be driven independently of one another.

Description

The invention relates to a device for producing a cylindrical-shaped or conical-shaped, circumferentially closed tubular body, in particular an exhaust pipe, an exhaust-gas silencer housing jacket and / or an exhaust-gas cleaning device housing jacket, with a tubular body central axis, which corresponds to a cylinder axis or a cone axis, comprising a receiving cone-shaped area for a cylindrical or cone-shaped chamber. a circumferential gap tubular body preform, the receiving space having a receiving space central axis that is oriented substantially parallel to the tubular body central axis, and a closing mechanism for closing the circumferential gap of the tubular body preform.

In contrast to the tubular body produced as an end or intermediate product by means of the device, a tubular body preform having a circumferential gap is therefore open at the circumference, i. H. not closed.

Sections of a cylinder jacket are also regarded as cylindrical jacket sections. A cylinder is to be understood as a so-called general cylinder. Its base can therefore have any geometry, for. B. a circle, an ellipse or a polygon. Irregular base areas are also conceivable.

The same applies to the term cone-shaped. Sections of a cone shell are also considered to be cone-shaped here. Analogous to the general cylinder, a cone is to be understood as a general cone with any base area.

In addition, the term cylinder-shaped or cone-shaped, circumferentially closed tubular body also includes those tubular bodies which comprise more than one cylinder jacket and / or more than one cone jacket. A tubular body can thus be composed of several cylinder jackets and / or cone jackets. The respective cylinder axes or the respective cone axes can be oriented to one another in any way, for. B. coaxial. One of these cone or cylinder axes is then regarded as the tube body center axis.

An exhaust gas purifier housing shell is e.g. B. a catalyst housing jacket or a particle filter housing jacket.
Devices of the type mentioned are known from the prior art. For example, the US 6,405,437 B1 such a device that is used in the manufacture of exhaust gas treatment systems.

The tubular bodies produced with devices of the type mentioned at the outset are often made from a sheet metal material. The inside of the tubular body can be empty. However, it is equally possible that, depending on the intended use of the tubular body, components are provided in the interior thereof, which are geometrically enclosed by the tubular body preform in the course of the closing thereof. At the same time, the component present in the interior of the tubular body can be secured in the tubular body.

Regardless of whether components are provided in the interior of the tubular body preform or not, devices of the type mentioned at the outset can only process tubular body preforms which have comparatively small dimensional tolerances. In the event that components are present inside the tubular body preform, these may only have small dimensional tolerances. So you must also meet narrow dimensional tolerances so that the assembly of tubular body preform and component can meet narrow dimensional tolerances.

In the case of exhaust gas cleaning device housing shells, in particular in the case of catalyst housing shells, in this connection, for example, a catalyst substrate or monolith can be provided in the interior of the exhaust gas cleaning device housing sheath. The monolith can be subject to tolerances as well as the preform of the exhaust gas purifier housing shell.

The object of the invention is therefore to improve a device of the type mentioned at the outset such that tubular body preforms can also be processed which only meet rough tolerances. Such tolerances are also included, which originate from a component provided inside the tubular body preform. A device is to be created, by means of which, despite the aforementioned tolerances, it is possible to produce a circumferentially closed tubular body quickly and reliably.

The object is achieved by a device of the type mentioned at the outset, in which the locking mechanism comprises at least two separate locking segments for closing the circumferential gap by abutment on the tubular body preform, which are arranged circumferentially with respect to the center axis of the receiving space and act radially to the center axis of the receiving space, each of which Lock segments an individual Drive unit is assigned so that the locking segments can be driven independently of one another. As a result, the closing segments can be moved independently of one another and thus take into account any possible dimensional deviations of the tubular body preform or of a component provided inside it. With such a device, the desired circumferentially closed tubular body can thus also be produced in a reliable manner from tubular body preforms which are subject to rough tolerances. The device can be used universally and, in addition to the production of the components for exhaust systems already mentioned at the outset, can also be used for the production of circumferentially closed tubular bodies which, for. B. for fire extinguishers or compressed air bottles. In addition, the device according to the invention is particularly well suited for the production of tubular bodies, in the interior of which components with tolerances are present. In this context, the individual drive units enable the tubular body to be closed circumferentially and at the same time to protect the components from damage or undesired mechanical loads. In the area of the exhaust systems, for example, a catalyst substrate or monolith can be provided in a tubular body designed as a catalyst housing jacket, which despite its tolerance-related character does not experience any pressure or force peaks during the circumferential closing of the catalyst housing jacket. To further protect it, the catalyst substrate can be mounted on a storage mat in the catalyst housing jacket.

The number of locking segments is basically freely selectable. In exemplary applications, three, four, five, six, eight, ten or twelve locking segments can be provided.

The device according to the invention is preferably designed such that the tubular body preform does not move along the central axis of the receiving space during its processing. For this purpose, an axial stop can be provided, against which the tubular body preform bears in the direction of the central axis of the receiving space during its processing.

Each of the individual drive units can comprise an electric motor, in particular wherein the individual drive unit is a linear drive unit. Electric motors and linear drive units have proven themselves in the prior art. They are reliable in operation and can be precisely controlled or regulated. The individual drive units and the locking segments connected to them can therefore be controlled or regulated just as precisely.

Alternatively, each of the individual drive units can comprise an industrial robot, preferably a multi-axis industrial robot. Each locking segment is then coupled to an end effector of an industrial robot. Industrial robots also ensure a precisely controlled or regulated movement of the associated locking segments. In addition, industrial robots permit essentially free programming of the movement path of the associated end effector, so that tubular bodies of a large geometric range can be produced by means of a device equipped in this way. Such devices can therefore be used particularly universally.

According to a variant, one or more of the closing segments can be driven only in the radial direction with respect to the central receiving space axis and / or one or more of the closing segments can be driven with respect to the central receiving space axis both in the radial direction and in the circumferential direction. The tubular body preforms can thus be reliably closed circumferentially. Movement in the circumferential direction can serve to convey material of the tubular body preform in the direction of the circumferential gap, so that the tendency of the tubular body preform to form folds is reduced. In addition, the tubular body preform can be reliably placed in this way on a component provided in its interior, in particular on a catalyst substrate or a monolith.

In the case of a closing segment which can be moved both in the radial direction and in the circumferential direction, the movement in the radial direction and the movement in the circumferential direction can be a combined movement, i. H. the movement of the closing segment in the radial direction depends on its circumferential movement or vice versa. The movement of the closing segment can thus be matched to a geometry and / or a material and / or another parameter of the tubular body preform. A high quality of the circumferentially closed tubular bodies produced is thus guaranteed.

One embodiment provides that one or more of the closing segments is or are coupled to an associated eccentric drive. By means of the eccentric drive, the assigned closing segments can be moved in the radial direction and / or in the circumferential direction with respect to the center axis of the receiving space. An eccentric drive is a simple and reliable solution for this. In particular, a high repeatability is achieved in series production of tubular bodies that are closed on the circumference.

At least one holding segment which is fixed with respect to the center of the receiving space can also be used be provided to which the tubular body preform can be placed. The holding segment is therefore immobile. It can serve to position the tubular body preform in the receiving space. For this purpose, it can include a stop. In this way, circumferentially closed tubular bodies can be produced simply and reliably.

Furthermore, the device can comprise a joining unit, in particular a welding unit or a soldering unit, by means of which the ends of the tubular body preform forming the circumferential gap can be connected to one another in a cohesive manner. The device thus serves both to close the peripheral gap geometrically and to connect the ends forming the peripheral gap in an integral manner. This is preferably done in a single clamping of the tubular body preform. In the event that a component is provided in the interior of the tubular body preform, it can be attached there at the same time. The device therefore fulfills several tasks essentially simultaneously. As a result, the device can be operated particularly economically. In addition, by avoiding reclamping operations, the precision and quality of the circumferentially closed tubular body produced by the device can also be increased.

A welding unit is preferably a laser welding unit. With such a welding unit, the welding energy can be introduced precisely into a joining zone, so that an accurate and mechanically resilient weld seam results. In addition, undesirable influences of the welding process on the tubular body preform can be reduced.

A soldering unit is preferably a laser soldering unit. The effects and advantages mentioned with regard to the laser welding unit apply analogously.

The joining unit is preferably arranged on a side of one of the closing segments facing away from the receiving space and can act on the tubular body preform through an opening provided in the closing segment. Such an arrangement of the joining unit results in an advantageous use of installation space. The device can thus be constructed in a particularly compact manner. In addition, despite the opening provided therein, the closing segment ensures that those sections of the tubular body preform that are in the region of the joining zone are precisely positioned. This ensures good starting conditions for creating an accurate and reliable joint. The result is a precisely manufactured and mechanically resilient tubular body.

The closing segment having the opening preferably has a closure element by means of which the opening can be optionally closed and released. The closure element brings about increased precision in the positioning of those sections of the tubular body preform which are in the region of the joining zone. In particular, the edges of the tubular body preform to be joined can be positioned by means of the closure element. In other words, the closing segment, which is provided with an opening and a closing element, corresponds to a standard closing segment when the opening is closed.

The closure element can be a closure slide which can be moved essentially along the central axis of the receiving space or transversely to the central axis of the receiving space with respect to the closing segment assigned to it. With reference to a cylindrical jacket-shaped or cone jacket-shaped tubular body arranged in the receiving space, the closure slide is thus axially, i. H. moved along a cylinder axis or a cone axis, radially or in the circumferential direction. The movement of the closing slide from a position closing the opening into a position releasing the opening can thus be carried out in a space-saving manner. In addition, such a slide can be easily coupled to an associated drive unit.

In one variant, the locking slide is guided over at least one rail on the associated closing segment. The rail can be designed as a groove in which a spring provided on the locking slide engages. The reverse case is also conceivable. Rollers or rollers which engage in such a rail can also be provided on the slide. In all variants, the locking slide can be moved easily and precisely on the locking segment. This makes it easy to open and close the opening.

In addition, a drive unit coupled to the closure element for actuating the closure element can be coupled to the joining unit in such a way that the drive unit can be actuated depending on a state of the joining unit. A movement of the closure element from a position closing the opening into a position opening the opening can therefore be coordinated with a joining process. For example, only a portion of the opening that is necessary to create the joint can always be released. The sections that have not yet been joined are thus positioned further by the closure element, which increases the accuracy and mechanical stability of the joint to be created.

A pressure control circuit is advantageously assigned to each locking segment and the respectively assigned individual drive unit, so that each of the locking segments can be actuated in a pressure-controlled manner. In this way, undesirable pressure and / or force loads on the tubular body preform and any component possibly provided in the interior thereof are reliably avoided. In the event that the tubular body is a catalyst housing jacket in which a monolith is provided, this can ensure that a pressure load on the monolith remains below a predetermined limit value.

According to one exemplary embodiment, the individual drive units can be operated synchronized with one another. As a result, the locking segments can be moved in a synchronized manner. The synchronization can be of a local and / or temporal nature. A pressure control already mentioned can also be provided. In this way, the tubular body preforms can be defined and reliably closed circumferentially.

Each of the closing segments can have a contact section, preferably a contact surface, for contacting the tubular body preform, in particular wherein a contour of the contact section essentially corresponds to an outer contour of the circumferentially closed tubular body. The desired outer contour of the tubular body can thus be specified by means of the closing segments.

The contact section can also comprise contact elements, only the contact elements coming into direct contact with the tubular body preform. The contact elements can serve to reduce friction between the tubular body preform and the closing segments. Then the contact elements can be rollers, rollers or balls which are rotatably mounted on the locking segment. As an alternative or in addition, the contact section can comprise protective elements which serve for gentle processing of the tubular body preform.

In one design alternative, at least one of the closing segments has a hold-down device which lies opposite the peripheral gap or projects radially into the peripheral gap. Such a hold-down device can be used to position the tubular body preform. This is particularly important for tubular body preforms that are not rotationally symmetrical or that require rotational positioning with respect to the center axis of the receiving space. If the hold-down device engages in the circumferential gap, it can be designed as a radial projection on the associated closing segment, which points in the direction of the receiving space. Such hold-downs are also known as swords. It can serve to prevent components provided inside the tubular body preform from engaging in the circumferential gap during the circumferential closing of the tubular body preform. In the event that the tubular body is a catalyst housing jacket, the hold-down device can serve to prevent a section of a mounting mat, via which a monolith is held inside the tubular body, from being pinched into the peripheral gap.

The closing segment equipped with the hold-down device is preferably the closing segment which also has the opening and optionally the closing element.

The hold-down device is further preferably arranged on the closure element, in particular connected to the closure element.

The closing segment, which lies opposite the peripheral gap, can also be referred to as a seam segment.

At least two locking segments can form a mounting segment, so that the locking segments forming the mounting segment can be assembled and disassembled. At least two closing segments therefore form a structurally connected unit. This means that the locking segments can be replaced quickly. This may be necessary for maintenance purposes or if the device is to be converted to produce tubular bodies with a different geometry.

In addition, the object is achieved by a method for producing a cylinder body-shaped or cone-shaped, circumferentially closed tubular body, in particular an exhaust pipe, an exhaust gas muffler housing shell and / or an exhaust gas cleaning device housing shell.

First, a tubular body preform with a circumferential gap is provided, in the interior of which a component can be provided. In the event that a catalyst housing jacket is to be produced, a catalyst housing jacket preform can be provided, in the interior of which a monolith is supported by a bearing mat.

The tubular body preform is then introduced into the receiving space. It can be positioned there with the help of a closing segment that lies opposite the circumferential gap.

The peripheral gap of the tubular body preform is then closed by reshaping the tubular body preform. In particular includes the forming a bending of the tubular body preform around the central axis of the receiving space.

The ends of the tubular body preform forming the peripheral gap can then be joined together. In particular, the ends are welded or soldered together. The joining is preferably carried out in the same clamping as the closing of the circumferential gap.

When joining the ends of the tubular body preform, either a joining energy source can be moved relative to the fixed tubular body preform or vice versa. However, it is preferred to move the joining energy source, that is to say the welding energy source or the soldering energy source, relative to the tubular body preform.

• - 1 eine erfindungsgemäße Vorrichtung zum Herstellen eines zylindermantelförmigen oder kegelmantelförmigen, umfangsmäßig geschlossenen Rohrkörpers gemäß einer ersten Ausführungsform,
• - 2 eine erfindungsgemäße Vorrichtung zum Herstellen eines zylindermantelförmigen oder kegelmantelförmigen, umfangsmäßig geschlossenen Rohrkörpers gemäß einer zweiten Ausführungsform,
• - 3 eine erfindungsgemäße Vorrichtung zum Herstellen eines zylindermantelförmigen oder kegelmantelförmigen, umfangsmäßig geschlossenen Rohrkörpers gemäß einer dritten Ausführungsform,
• - 4 die Vorrichtung aus 3 in einem anderen Betriebszustand,
• - 5 ein Detail der Vorrichtung aus den 3 und 4,
• - 6 eine Ansicht eines Verschlusselements aus 5 entlang der Richtung VI,
• - 7 eine Prinzipskizze zur Erläuterung des Details aus 5 und
• - 8 eine erfindungsgemäße Vorrichtung zum Herstellen eines zylindermantelförmigen oder kegelmantelförmigen, umfangsmäßig geschlossenen Rohrkörpers gemäß einer vierten Ausführungsform.

The invention is explained below with reference to various exemplary embodiments, which are shown in the accompanying drawings. Show it:

• - 1 1 a device according to the invention for producing a cylindrical or cone-shaped, circumferentially closed tubular body according to a first embodiment,
• - 2 A device according to the invention for producing a cylindrical or cone-shaped, circumferentially closed tubular body according to a second embodiment,
• - 3 A device according to the invention for producing a cylindrical or cone-shaped, circumferentially closed tubular body according to a third embodiment,
• - 4 the device 3 in another operating state,
• - 5 a detail of the device from the 3 and 4 .
• - 6 a view of a closure element 5 along the direction VI,
• - 7 a schematic diagram to explain the details 5 and
• - 8th a device according to the invention for producing a cylindrical or cone-shaped, circumferentially closed tubular body according to a fourth embodiment.

1 shows a device 10 for producing a cylindrical jacket-shaped, circumferentially closed tubular body 12 , which is illustrated by a dash-dotted line.

With the tubular body 12 it is in particular an exhaust gas purifier housing jacket, for. B. a catalyst housing jacket, an exhaust pipe or an exhaust silencer housing jacket. In the present case, however, the device 10 are explained in general terms.

The device 10 includes a recording room 14 , which for the inclusion of a cylindrical jacket, a circumferential gap 16 having tubular body preform 18 is provided. The tubular body preform 18 is in 1 illustrated with a dashed line and already in the recording room 14 brought in.

The recording room 14 has a receiving space central axis 20 on, which in the illustrated embodiments essentially parallel to a tube body center axis 22 is oriented.

In addition, the device 10 a closing mechanism for closing the peripheral gap 16 on. In the embodiment according to FIG 1 eight separate locking segments 24 ,

These are with respect to the central axis of the recording space 20 arranged circumferentially distributed and act radially to this.

Each of the locking segments 24 has a contact section 24a which is to be applied to the tubular body preform 18 is trained.

In the embodiment according to 1 are the contact sections 24a designed as essentially flat surfaces. Alternatively, contact surfaces can also be provided, the contour of which essentially corresponds to an outer contour of the circumferentially closed tubular body 12 equivalent.

Each of the locking segments 24 is an individual drive unit 26 assigned. The device 10 also includes eight individual drive units 26 ,

Each of the individual drive units can 26 comprise an electric motor. The drive units can also 26 Be linear drive units. In other embodiments, each of the individual drive units 26 an industrial robot, for example a multi-axis industrial robot. It is also conceivable for the closing segments 24 by means of hydraulic or pneumatic drive units 26 to operate.

In the in 1 The embodiment shown are all closing segments 24 with respect to the central axis of the recording space 20 can only be driven in the radial direction.

It can be any locking segment 24 and the associated individual drive unit 26 a pressure control loop can be assigned so that each of the closing segments 24 can be operated under pressure control. It is a particularly gentle way of closing the circumferential gap 16 reached, pressure and force peaks are avoided.

In addition, the individual drive units 26 operated synchronized to each other. The movements of the individual drive units 26 depend on each other.

The three in form for easy assembly and disassembly 1 locking segments shown on the left 24 an assembly segment 28 , The same applies to the in 1 three locking segments shown on the right 24 ,

The one assembly segment 28 forming closing segments 24 can be assembled and disassembled.

The device 10 according to 1 works as follows.

First, a tubular body preform 18 with a perimeter gap 16 in the recording room 14 inserted. By means of the device 10 should now the perimeter gap 16 getting closed.

This is done in that the mutually separate closing segments 24 to the tubular body preform 18 be created and deform it in such a way, in particular bend that the circumferential gap 16 is closed and a circumferentially closed tubular body 12 arises. The tube body central axis 22 runs essentially parallel to the central axis of the recording space 20 ,

For this, the locking segments 24 by means of their respective assigned individual drive units 26 with respect to the central axis of the recording space 20 move in the radial direction.

2 shows a second embodiment of the device 10 , It differs from the first embodiment only in that 1 that the number of separate locking segments 24 is reduced to six.

A third embodiment of the device 10 is in the 3 and 4 shown. Only the differences from the first two embodiments are discussed. For the rest, reference is made to the above explanations.

The device 10 comprises three locking segments 24 ,

It is in the 3 and 4 closing segment arranged at the top 24 can only be driven in the radial direction.

The in the 3 and 4 locking segments arranged on the left and right 24 are each assigned an eccentric drive 30 coupled. This comprises four eccentric roles 32 , in pairs on one around the central axis of the recording space 20 encircling ring band 34 are led.

The locking segments 24 that with the eccentric drive 30 are coupled, so with respect to the central axis of the receiving space 20 are driven in the circumferential direction. Because of the eccentricity of the eccentric rollers 32 results from the movement in the circumferential direction also with respect to the central axis of the receiving space 20 radial infeed of the locking segments 24 , In this way, the tubular body preform 18 deformed so that the circumferential gap 16 is closed.

This is particularly based on a synopsis of the 3 and 4 clearly, with the closing segments shown on the left and right 24 are shown in different circumferential positions.

The device 10 further includes a with respect to the central space axis 20 fixed holding segment 36 , This is in the 3 and 4 each shown below so that the tubular body preform 18 and the circumferentially closed tubular body 12 on the holding segment 36 can rest.

In addition, the device 10 according to the third embodiment, a joining unit 38 on. It is in particular a welding unit or a soldering unit by means of which the circumferential gap 16 forming ends of the tubular body preform 18 cohesive can be connected.

The joining unit 38 is on one of the recording room 14 opposite side of the in the 3 and 4 closing segment shown above 24 arranged.

So that the joining unit 38 on the tubular body preform 18 can act is in this locking segment 24 an opening 40 provided (see 5 ).

The opening 40 can by means of a closure element designed as a closure slide 42 optionally locked and released.

For this purpose, the locking slide is essentially along the central axis of the receiving space 20 movable.

That the opening 40 comprehensive locking segment 24 as well as its interaction with the joining unit 38 is in the 5 to 7 presented in detail.

This is the joining unit 38 out 7 a laser welding unit or a laser soldering unit. The laser beam shown only schematically 38a enters through the released opening 40 through it so that the the perimeter gap 16 forming ends of the tubular body preform 18 can connect cohesively.

On the closure element 42 can also use a so-called sword or hold-down 44 be provided in 6 is shown in detail.

This hold-down 44 is designed as a projection and radially in the direction of the receiving space 14 oriented so that it is in the perimeter gap 16 protrudes. It is used to position the tubular body preform 18 ,

In addition, the closure element 42 protrusions on both sides 46 on, each in a groove-shaped rail 48 intervene on the locking segment 24 is provided. In this way, the closure element 42 towards the locking segment 24 slidably mounted.

The hold-down 44 and the closure element 42 are made in one piece.

In 8th is another embodiment of the device 10 shown. Its structure corresponds essentially to that of the device 10 from the 3 and 4 , However, the device is now 10 for the production of a circumferentially closed tubular body 12 formed, which has an elliptical cross section.

The device 10 was in the manufacture of cylindrical jacket-shaped, circumferentially closed tubular bodies 12 explained. However, it can also be used to produce cone-shaped, circumferentially closed tubular bodies 12 be used. Then the contact sections run 24a of the locking segments 24 or the locking segments 24 overall not parallel to the central axis of the recording space 20 , but enclose an angle with it.

QUOTES INCLUDE IN THE DESCRIPTION

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Patent literature cited

• US 6405437 B1 [0006]

Claims (15)

Device (10) for producing a cylindrical jacket-shaped or conical jacket-shaped, circumferentially closed tubular body (12), in particular an exhaust pipe, an exhaust silencer housing jacket and / or an exhaust gas cleaning device housing jacket, with a tubular body central axis (22) which corresponds to a cylinder axis or a cone axis (comprising a receiving space) 14) for a cylindrical jacket-shaped or conical jacket-shaped, a circumferential gap (16) having tubular body preform (18), wherein the receiving space (14) has a receiving space central axis (20) which is oriented essentially parallel to the tubular body central axis (22), and a locking mechanism for Closing the circumferential gap (16) of the tubular body preform (18), characterized in that the closing mechanism comprises at least two mutually separate closing segments (24) for closing the circumferential gap (16) by abutment against the tubular body preform (18) he center of the receiving space (20) is arranged circumferentially distributed and act radially to the center of the receiving space (20), each of the locking segments (24) being assigned an individual drive unit (26) so that the locking segments (24) can be driven independently of one another. Device (10) after Claim 1 , characterized in that each of the individual drive units (26) comprises an electric motor, in particular wherein the individual drive unit (26) is a linear drive unit. Device (10) after Claim 1 , characterized in that each of the individual drive units (26) comprises an industrial robot, preferably a multi-axis industrial robot. Device (10) according to one of the preceding claims, characterized in that one or more of the closing segments (24) with respect to the central axis (20) of the receiving space can only be driven in the radial direction and / or that one or more of the closing segments (24) are related the receiving space center axis (20) can be driven both in the radial direction and in the circumferential direction. Device (10) according to one of the preceding claims, characterized in that one or more of the closing segments (24) is or are coupled to a respectively assigned eccentric drive (30). Device (10) according to one of the preceding claims, characterized by at least one holding segment (36) which is fixed with respect to the center of the receiving space (20) and against which the tubular body preform (18) can be placed. Device (10) according to one of the preceding claims, characterized by a joining unit (38), in particular a welding unit or a soldering unit, by means of which the ends of the tubular body preform (18) forming the circumferential gap (16) can be integrally connected to one another. Device (10) after Claim 7 characterized in that the joining unit (38) is arranged on a side of one of the closing segments (24) facing away from the receiving space (14) and acts on the tubular body preform (18) through an opening (40) provided in the closing segment (24) can. Device (10) after Claim 8 , characterized in that the closing segment (24) having the opening (40) has a closure element (42) by means of which the opening (40) can be optionally closed and released. Device (10) after Claim 9 characterized in that the closure element (42) is a closure slide which can be moved essentially along the central axis of the receiving space (20) or transversely to the central axis of the receiving space (20) with respect to the closing segment (24) assigned to it. Device (10) according to one of the preceding claims, characterized in that a pressure control circuit is assigned to each locking segment (24) and the respectively assigned individual drive unit (26), so that each of the locking segments (24) can be actuated in a pressure-controlled manner. Device (10) according to one of the preceding claims, characterized in that the individual drive units (26) can be operated synchronously with one another. Device (10) according to one of the preceding claims, characterized in that each of the closing segments (24) has a contact section (24a), preferably a contact surface, for contact with the tubular body preform (18), in particular with a contour of the contact section (24a) essentially corresponds to an outer contour of the circumferentially closed tubular body (12). Device (10) according to one of the preceding claims, characterized in that at least one of the closing segments (24) has a hold-down device (44) which corresponds to the peripheral gap (16) lies opposite or protrudes radially into the circumferential gap (16). Device (10) according to one of the preceding claims, characterized in that at least two locking segments (24) each form a mounting segment (28) so that the locking segments (24) forming the mounting segment (28) can be assembled and disassembled.

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