EP3423205B1 - Device and method for shaping a tubular workpiece - Google Patents

Description

The invention relates to a device for forming a tubular workpiece according to the preamble of claim 1 and a method according to the preamble of claim 12. The device comprises a machine bed, a headstock mounted on the machine bed, a spinning mandrel mounted on the headstock for receiving the tubular workpiece a chuck mounted on the headstock for chucking a first axial end of the tubular workpiece and at least one forming roller for forming the tubular workpiece around the spinning mandrel.

A generic device is for example from the EP 2 210 682 A1 known.

The invention has for its object to provide an apparatus and a method for forming a tubular workpiece, which allow a particularly precise and efficient forming.

The object we achieved by a device having the features of claim 1 and a method of claim 12. Preferred embodiments of the invention are indicated in the dependent claims.

The device according to the invention is characterized in that a tailstock is provided on which a receptacle for receiving and holding the second axial end of the tubular workpiece is provided, wherein the tailstock is mounted axially displaceably on the machine bed.

A basic idea of the invention can be seen in centering the axial end of the workpiece lying opposite the chuck on the headstock in a preferably sleeve-shaped or trough-shaped receptacle in order to ensure precise mounting of the workpiece. Preferably, the receptacle partially or completely encloses the axial end of the workpiece and holds the workpiece precisely in the axis of the spinning mandrel.

In a preferred embodiment, the receptacle has a second chuck for clamping the second axial end of the tubular workpiece. The workpiece is thus clamped in this case at both axial ends in each case a chuck and held reliably in this way.

Preferably, the second chuck is rotatably mounted on the tailstock and set in rotation by the workpiece. The chuck is thus preferably freely stored or storable, so that a rotation of the chuck can be generated by a rotation of the workpiece. The workpiece is reliably centered in the axis of the spinning mandrel by the second chuck. At the same time a free rotation of the clamped workpiece is ensured by the rotatable mounting of the second chuck.

In a further preferred embodiment, a rotary drive is provided for rotationally driving the second chuck. By introducing a torque into the second axial end of the workpiece torsion-free ends can be formed. The chuck can basically also be formed by a driver.

According to the invention, the tailstock is mounted axially displaceably on the machine bed. Preferably, the tailstock is stored with the chuck axially free on the machine bed or storable, so that by axial material flow of the workpiece axial displacement of the tailstock can be effected with the chuck. The tailstock can thus be moved freely preferably by an elongation of the workpiece.

The deformation of the workpiece can be advantageously assisted by providing an axial drive for the axial movement of the tailstock together with the second chuck, in particular for pulling the workpiece.

By supporting the axial material flow of the workpiece by a tensile force, the material undergoes tensile forces during the forming, on the one hand the Facilitate material flow and on the other hand achieve a high straightness of the workpiece.

In a further preferred embodiment, a mandrel for receiving deformed material of the tubular workpiece is provided on the tailstock. The mandrel may in particular be provided to catch and / or guide material which flows axially outward over the spinning mandrel. The additional collecting mandrel also increases the straightness of the workpiece to be formed.

A further preferred embodiment of the invention is that the spinning mandrel has an end-side mandrel portion, which is rotatably mounted on a mandrel rod, and that an axially and / or radially movable support means is provided for supporting the mandrel rod. The mandrel bar can in particular non-rotating, so rotationally fixed, be mounted on the headstock. The deformation of the workpiece is preferably carried out in the region of the rotatably mounted on the mandrel rod end-side mandrel portion, which forms the actual forming mandrel.

The workpiece can be moved in the axial direction relative to the forming mandrel to be formed between forming mandrel and forming roller. The forming mandrel, that is to say the end-side mandrel section, in this case preferably does not correspond to the internal shape of the workpiece to be reshaped. Rather, the inner shape of the workpiece is determined in each case by the relative position of forming mandrel and forming roller to each other. To produce a pipe section with a constant inner and outer diameter, the workpiece can be moved in the axial direction with respect to an axially fixed mandrel and an axially fixed forming roller.

In this case, the mandrel bar can have a large axial length in comparison to the actual mandrel, that is to say the end-side mandrel section. In order to reliably support the possibly particularly long mandrel bar, with or without a workpiece arranged around it, the supporting device can preferably be moved in the radial direction. The radial movability also allows adaptation to different outer diameters of the workpiece section to be supported. The axial movability allows reliable support of the mandrel bar and / or the workpiece during the forming process when the mandrel bar is moved axially to the machine bed and / or headstock during forming. Even when loading or unloading the movable support means, which can also be referred to as Lynette, provide reliable support. The support means preferably comprises a plurality of rotatably mounted support rollers to support a rotating workpiece or a rotating mandrel bar.

In a further preferred embodiment, a guide device is provided for axially guiding a region of the tubular workpiece. The guide device is preferably arranged immediately in front of the forming roller, in particular in a still unshaped area of the workpiece. The guide device is preferably configured to hold the workpiece centrally in the axis of rotation of the spinning mandrel. The guide device supports the straightness of the finished part, in particular during a forming by means of only one forming roller.

A particularly reliable centering of the workpiece can be achieved in that the guide means the tubular workpiece ring or ringweegmentförmig at least partially encloses. The particular sleeve or trough-shaped guide device supports the workpiece from the outside and performs this in the axial direction. The guide device is preferably arranged non-rotating on the machine bed. The workpiece slides along the guide means.

Preferably, the guide device is designed to guide a rotating workpiece. The guide device can for this purpose have a sliding surface or a rotatably mounted guide sleeve.

It is particularly preferred that the guide device has rotatable or non-rotatably mounted sliding and / or guide jaws. These support the workpiece from the outside and allow reliable centering and guiding a rotating workpiece.

Particular aspects of the device according to the invention are further described below:
The invention relates to a method and a device in which at least one tool mandrel axially as a function of the radial delivery of at least one retractable or pressure roller is moved so that between the pressure roller and mandrel different gap dimensions or wall thicknesses can be created depending on the diameter.

1. Limitation and inclination of the roll axis

1. a) Je nach Einstellung der Schränkung der Drückwalze kann eine Unterstützung des Materialflusses in axialer Richtung und in radialer Richtung vom großen zum kleineren Durchmesser erfolgen. Die Drückwalze weist dabei mindestens durch ihre Einlaufschräge unterschiedliche Arbeitsdurchmesser entlang der Walzendrehachse auf, sie können jedoch mit mehreren Arbeitsradien auf unterschiedlichem Durchmesser versehen sein. Ferner können diese vorzugsweise so aufgeteilt sein, dass sich jeder Arbeitsradius entsprechen seiner Abrollumfangsgeschwindigkeit optimal an den Materialfluss anpasst. Dabei können mehrere Walzen eingesetzt werden, die nacheinander in den Eingriff gebracht werden. Ferner können diese Walzen in ihrer axialen Position identisch sein. Besonders vorteilhaft für große Umformleistungen ist jedoch ein axialer und radialer Versatz zwischen den nacheinander eingreifenden Arbeitsradien beziehungsweise Umformflächen der Drückwalze. Besonders vorteilhaft ist dabei, dass der Materialfluss beziehungsweise das aufsteigende Material zwischen den Umformradien der Walzen einer polygonförmigen Ausbildung des Materials unter den Umformwalzen entgegenwirkt und somit das Material geschont wird. Folglich können größere Umformgrade erzielt werden.
2. b) Darüber hinaus ist es vorteilhaft, die Drückwalze über einen Hilfsantrieb zu beschleunigen, bevor die Umformwalze in Materialkontakt gebracht wird. Besonders vorteilhaft kann es sein, wenn jeder Arbeitsradius der Drückwalze in einem Verhältnis zur Umfangsgeschwindigkeit des Werkstückes aktiv angetrieben wird, so dass der über das Bauteil oder den Werkzeugdorn einzuleitende Drehmomentbedarf deutlich gesenkt werden kann.
3. c) Durch den unterschiedlichen Durchmesser an der Umformwalze sowie die Schränkung und die Neigung der Walzenachse ergeben sich stark unterschiedliche Unterstützungen beim Materialfluss, die dazu führen, dass der Werkstoff anfangs hohe Zugkräfte erfährt und dann abwechselnd durch Zug- und Druckkräfte umgeformt wird, so dass deutlich höhere Umformgrade erzielt werden können. Beispielweise kann der kleine Durchmesser am großen Werkstückdurchmesser mit deutlich höherer Drehzahl abrollen als der große Rollendurchmesser am kleineren Werkstückdurchmesser, so dass sich folglich über die identische Schrägstellung der Walzen unterschiedliche Relativvorschübe im Werkstofffluss ergeben, die folglich große Druckkräfte ins Material einleiten beziehungsweise hohe Reibungskräfte auf das Bauteil ausüben.
4. d) Die hohen Reibungskräfte und die daraus erhöhten Umformtemperaturen wirken sich bei einigen Werkstoffen, wie zum Beispiel auf Aluminiumlegierungen, EN-AW 6060, besonders vorteilhaft aus, so dass deutlich höhere Umformgrade bei deutlich geringeren Umformkräften möglich sind. Ferner wird durch die Reibkräfte, die großen Reduktionen und die hohen Umformgeschwindigkeit ein besonders feinkörniges Gefüge erzielt, welches im Laufe der Umformung deutlich höhere Umformgrade ermöglicht.
5. e) Die Schrägstellung der Walzenachse erfolgt vorzugsweise im Bereich von minus 60 Grad bis plus 45 Grad, je nach Winkel des Dornes und Ausführung der Umformwalze bzw. Einlaufwinkel und Auslaufwinkel der Drückwalze. Beim Einsatz eines konischen Dorns zur Herstellung unterschiedlicher Durchmesser hat sich ein Winkel von minus 15 Grad als besonders vorteilhaft erwiesen, da die hohen Vorschubkräfte somit optimal in die Lagerung eingeleitet werden können und das Abrollverhalten der Umformwalze sowie das Fließverhalten des Materials begünstigt werden.

The offset of at least one pressure roller at an angle of 0-15 °, combined with the inclination of the axis of rotation of at least one forming roller relative to the axis of rotation of the workpiece or the mandrel depending on the material, workpiece feed and speed allows a higher diameter and wall thickness reduction and reduction the forming forces or services.

1. a) Depending on the setting of the setting of the pressure roller can support the flow of material in the axial direction and in the radial direction from the large to the smaller diameter. The pressure roller has at least by its inlet slope different working diameter along the roll axis of rotation, but they can be provided with multiple working radii on different diameters. Furthermore, these can preferably be divided so that each working radius corresponds optimally to its material flow according to its rolling circumferential speed. Several rollers can be used, which are brought into engagement one after the other. Furthermore, these rollers may be identical in their axial position. However, an axial and radial offset between the successively engaging working radii or forming surfaces of the pressure roller is particularly advantageous for large forming capacities. It is particularly advantageous that the material flow or the rising material counteracts between the Umformradien the rollers of a polygonal design of the material under the forming rollers and thus the material is protected. Consequently, larger degrees of deformation can be achieved.
2. b) Moreover, it is advantageous to accelerate the pressure roller via an auxiliary drive before the forming roller is brought into material contact. It may be particularly advantageous if each working radius of the pressure roller is actively driven in a ratio to the peripheral speed of the workpiece, so that the can be significantly reduced via the component or the mandrel to be initiated torque requirement.
3. c) Due to the different diameter of the forming roller and the setting and the inclination of the roll axis, greatly different supports in the material flow, which cause the material initially high tensile forces and then alternately deformed by tensile and compressive forces, so clearly higher degrees of deformation can be achieved. For example, the small diameter at the large workpiece diameter can roll at a significantly higher speed than the large roller diameter at the smaller workpiece diameter, so that different relative feed rates in the material flow result from the identical skewed position of the rollers, which consequently introduce large pressure forces into the material or high frictional forces on the component exercise.
4. d) The high frictional forces and the resulting higher forming temperatures have a particularly advantageous effect on some materials, such as aluminum alloys, EN-AW 6060, so that significantly higher forming rates are possible with significantly lower forming forces. Furthermore, a particularly fine-grained microstructure is achieved by the frictional forces, the large reductions and the high forming speed, which allows significantly higher degrees of deformation in the course of forming.
5. e) The inclination of the roll axis is preferably in the range of minus 60 degrees to plus 45 degrees, depending on the angle of the mandrel and execution of the forming roll or inlet angle and outlet angle of the pressure roller. When using a conical mandrel for producing different diameters, an angle of minus 15 degrees has proven to be particularly advantageous because the high feed forces can thus be optimally introduced into the storage and the rolling behavior of the forming roller and the flow behavior of the material are favored.

2nd tailstock

1. a) Der Reitstock ist mit einem Spannfutter ausgestattet, das das freie Ende des umzuformenden Werkstücks aufnimmt und während des Umformprozesses hält. Das Spannfutter wird beim Umformprozess durch das Werkstück in Drehung versetzt. Der axiale Materialfluss beim Walzprozess sorgt für eine axiale Verschiebung des Spannfutters mit Reitstock.
2. b) Besonders vorteilhaft ist es jedoch, den axialen Materialfluss des Werkstückes mit einer Zugkraft, durch einen Spannfutter mit ziehendem Reitstock, zu unterstützen. Dadurch erfährt der Werkstoff während des Fließvorganges zwischen Drückwalze und Dorn zusätzlich zu den Druckkräften auch Zugkräfte, die zum einem den Materialfluss erleichtern und zum anderen die Geradheit der Werkstücke, ins besondere bei kleinen Durchmessern und hohen Durchmesserreduzierungen, deutlich verbessern. Dadurch kann ein anschließendes Richten langer Werkstücke, wie beispielsweise Straßenlaternenmasten, entfallen. Dabei kann der Reitstock sowohl weggesteuert als auch kraftgesteuert mit konstanter oder veränderlicher Kraft verfahren werden.
3. c) Der Reitstock kann auch mit einem zweiten Dorn ausgestattet sein, der das über den ersten Werkzeugdorn umgeformte Material auffängt und/oder führt. Auch dadurch lässt sich die Geradheit der Werkstücke deutlich verbessern.
4. d) Außerdem kann der Reitstock in einer besonderen Form ausgeführt sein, so dass das Drehmoment auf das umzuformende Bauteil von beiden Enden des Werkstücks durch Spannfutter oder Mitnehmer bzw. Mitnehmerverzahnung kraft- oder formschlüssig eingeleitet wird. Dies ermöglicht bei der Rohrumformung verwindungsfreie Enden. Dies ist besonders vorteilhaft für die Umformung geschweißter Rohre, bei denen die Schweißnähte an den Enden eine bestimmte Lage zueinander aufweisen müssen, wie zum Beispiel Halbzeuge für eine anschließenden Hydro- und/oder Biegeumformung von symmetrisch auf Torsion belasteten Bauteilen.
5. e) Eine besonders vorteilhafte Ausführung des Reitstockes ermöglicht die Kompensierung der Materialverlängerung aufgrund unterschiedlicher Wandstärken im Ausgangsmaterial durch die Zustellung der Walzen und/oder des Dornes im Prozess von der Maschinensteuerung, so dass eine einheitliche Endlänge des Fertigproduktes erzielt wird.
6. f) Ferner kann der Reitstock zur Stabilisierung gegen Schwingen zusätzlich von einer der Lynetten gestützt werden.

The tailstock can perform different functions.

1. a) The tailstock is equipped with a chuck which receives the free end of the workpiece to be formed and holds during the forming process. The chuck is rotated by the workpiece during the forming process. The axial material flow during the rolling process ensures axial displacement of the chuck with tailstock.
2. b) However, it is particularly advantageous to support the axial material flow of the workpiece with a tensile force, by means of a chuck with a drawing tailstock. As a result, the material undergoes, in addition to the compressive forces, tensile forces which, on the one hand, facilitate the material flow and, on the other hand, significantly improve the straightness of the workpieces, in particular for small diameters and high diameter reductions, between the pressure roller and mandrel. This can be a subsequent straightening long workpieces, such as street lamp poles omitted. The tailstock can be moved away as well as force-controlled with constant or variable force.
3. c) The tailstock may also be equipped with a second mandrel which catches and / or guides the material formed over the first mandrel. This also significantly improves the straightness of the workpieces.
4. d) In addition, the tailstock can be designed in a special shape, so that the torque on the component to be formed from both ends of the workpiece by chuck or driver or driver toothing force or positively introduced. This allows torsion-free ends during tube forming. This is particularly advantageous for forming welded tubes where the welds at the ends must have a certain position relative to each other, such as semi-finished products for subsequent hydro and / or flexural deformation of symmetrically torsionally loaded components.
5. e) A particularly advantageous embodiment of the tailstock allows the compensation of the material extension due to different wall thicknesses in the starting material by the delivery of the rollers and / or the mandrel in the process of the machine control, so that a uniform final length of the finished product is achieved.
6. f) Furthermore, the tailstock can be additionally supported by one of the Lynetten for stabilization against vibration.

3. Material guide

1. a) Hierzu wird vorzugsweise das Werkstück von außen durch eine stützende und/oder möglichst voll umschließende Einrichtung in axialer Richtung geführt. Zusätzlich ermöglicht die Führung auch die Rotation des Werkstückes.
   Diese kann beispielsweise ringförmig das Bauteil umschließen, so dass zusätzlich eine Formstabilität erzielt wird.
2. b) Zur besseren Materialausnutzung kann eine bessere Ausführungsvariante so teilbar und/oder verschiebbar ausgeführt sein, dass das Spannfutter der Hauptspindeleinheit bis unmittelbar bis vor die Umformrollen beziehungsweise Umformzone die Führung des Rohmaterial übernimmt beziehungsweise somit eine optimalere Materialausnutzung ermöglicht.
3. c) Alternativ kann auch eine drehbar gelagerte Stützeinrichtung vorgesehen sein oder das Werkstück über partiell angeordnete Stütz- und Führungsauflagen zentrisch geführt werden. Beispielsweise kann ein zentrisch gelagertes Backenfutter mit Gleit- und Führungsbacken das Werkstück in der Rotation von außen stützen und führen.
4. d) Eine bevorzugte Ausführungsform der rohteildurchmesserabhängigen Wechselteile ermöglicht zusätzliche Kühlung beziehungsweise Schmierung zur Verschleißreduzierung. Als Führungsmaterial werden vorzugsweise verschleiß-, hitze- und emulsionsbeständige Materialien eingesetzt, die weich genug sind, um keine Oberflächenbeschädigungen am Rohmaterial zu verursachen.

Especially with large diameter reductions and one-sided deformation by only one forming roll, a centric guidance of the raw material is preferably used immediately before the forming zone. As a result, the finished part can not be pushed substantially radially out of the center of the machine, despite the imbalance of forces between the forming rollers.

1. a) For this purpose, preferably, the workpiece is guided from the outside by a supporting and / or as fully as possible enclosing device in the axial direction. In addition, the guide also allows the rotation of the workpiece.
   This can, for example, enclose the component in a ring shape, so that in addition dimensional stability is achieved.
2. b) For better material utilization, a better embodiment variant can be designed to be divisible and / or displaceable so that the chuck of the main spindle unit takes over the guidance of the raw material until immediately before the forming rolls or forming zone, respectively, thus enabling a more optimal use of material.
3. c) Alternatively, a rotatably mounted support means may be provided or the workpiece over partially arranged support and guide pads are guided centrally. For example, a centrally mounted jaw chuck with sliding and guide jaws support and guide the workpiece in rotation from the outside.
4. d) A preferred embodiment of the tube diameter-dependent change parts allows additional cooling or lubrication to reduce wear. As a guide material preferably wear, heat and emulsion resistant materials are used, which are soft enough not to cause surface damage to the raw material.

4. Centrically exciting or delivering Lynetten

To center the mandrel, the raw material and the finished part, Lynetten and support units are used on the machine in front of and behind the forming rollers. The Lynetten before the forming rollers are movable depending on the feed movement of the main spindle drive unit radially out of the center and in addition axially, axially displaceable in dependence on the mandrel. Thus, the long mandrel is so well supported in every situation, so that a buckling of the mandrel bar is impossible.

5. Cooling water device

For better process control of the forming, flow measuring devices can be installed in the machine, which allow a simple flow rate control. This can preferably be done manually, but also automated. In addition, the consistency of the cooling lubricant or coolant can also be measured. An impermissible deviation of the cooling lubricant in its consistency is displayed and / or automatically corrected. Due to the high forming capacity, emulsion systems with high filter performance are used by belt filters and / or magnetic separators. The emulsion is supplied via nozzles, which preferably ensure a particularly high and / or low heat dissipation.

6. Loading and unloading

1. a) Das Beladen und Entladen der Werkstücke erfolgt vorzugsweise auf unterschiedlichen Seiten der Maschine und hinter der Bearbeitungseinheit beziehungsweise Umformzone.
2. b) Vorzugweise werden mehrere Rohre zeitgleich der Zuführung der Beladeeinrichtung über eine Schräge zugeführt beziehungsweise aufgelegt. Über eine Vereinzelung kann jeweils ein Rohteil der Maschine zugeführt werden.
3. c) Auf der Entladeseite können die Werkstücke über eine Schräge auslaufen beziehungsweise zur Folgebearbeitung weitergeleitet oder für den Weitertransport gesammelt werden.

To increase productivity, the machine is equipped with an automatic parts feeder and divider. This can preferably be automatically set to the appropriate workpiece dimensions or manually converted with little effort diameter-related.

1. a) The loading and unloading of the workpieces is preferably carried out on different sides of the machine and behind the processing unit or forming zone.
2. b) Preferably, several tubes are simultaneously fed to the supply of the loading device via a slope or placed. About a singling a blank of the machine can be supplied in each case.
3. c) On the unloading side, the workpieces can exit via a slope or forwarded for subsequent processing or collected for further transport.

7. Mandrel

1. a) Die Dornstange kann zur Reduzierung der Herstellkosten aus mehreren einzelnen kürzeren Abschnitten zusammengesetzt sein. Um die Torsionskräfte, Knickkräfte und Schwingungen der Dornstange möglichst gering zu halten, ist es besonders vorteilhaft, die Lagerung des Dornes unmittelbar zwischen Dorn und Dornstange einzusetzen und die Dornstange nicht rotieren zu lassen. Auf der Dornstange wird ein möglichst schnellwechselbarer Dorn befestigt. Die Lagerung zur Aufnahme der Rotation des Dornes beziehungsweise der Kräfte kann sowohl am Anfang und am Ende der Dornstange erfolgen.
2. b) Bei kleineren Rohteildurchmessern kann eine weitere bevorzugte Variante der Dornlagerung so aussehen, dass sich der Dorn mitdreht beziehungsweise die Dornstange drehbar gelagert ist, um die hohen Axialkräfte mit einer entsprechend groß dimensionierten Lagerung aufnehmen zu können.
3. c) Abhängig vom Innendurchmesser des Rohteils können vorzugsweise partiell wirkende Abstützringe auf der Dornstange befestigt werden, die die Dornstange am Innendurchmesser der Rohteils und/oder an den Stützrollen der Lynetten abstützen und somit die Dornstange zentrieren beziehungsweise ein Ausknicken verhindern.
   Eine weitere bevorzugte Ausführung sieht vor, dass diese Ringe geteilt sind, drehbar gelagert sind und axial in der Position der Stützrollen der jeweiligen Lynetten angeordnet sind.
4. d) Zur Durchführung von Schmierstoff und/oder Kühlschmierstoff und/oder Kühlwasser ist die Dornstange bevorzugt als Hohlkörper ausgeführt, so dass Rohrleitungen oder/und Schläuche für die benötigten Medien im Hohlraum verlegt werden können.

The mandrel rod is used to extend the mandrel and must be performed depending on the length of the maximum reshaped blank. In the case of large lengths of pipe which require a particularly long mandrel, the mandrel bar is preferably designed in such a way that it is possible to support both the mandrel and the mandrel with raw material so as to ensure optimal support during loading and unloading and forming, even at higher speeds.

1. a) The mandrel can be composed of several individual shorter sections to reduce the manufacturing costs. In order to keep the torsional forces, buckling forces and vibrations of the mandrel as small as possible, it is particularly advantageous to use the bearing of the mandrel directly between the mandrel and mandrel and not to let the mandrel rotate. On the mandrel a fast as possible changeable mandrel is attached. The bearing for receiving the rotation of the mandrel or the forces can be done both at the beginning and at the end of the mandrel.
2. b) For smaller Rohteildurchmessern another preferred variant of the mandrel storage look like that rotates with the mandrel or the mandrel is rotatably mounted to accommodate the high axial forces with a correspondingly large-sized storage can.
3. c) Depending on the inner diameter of the blank preferably partially acting support rings can be mounted on the mandrel, which support the mandrel on the inner diameter of the blank and / or on the support rollers of Lynetten and thus center the mandrel or prevent buckling.
   A further preferred embodiment provides that these rings are divided, are rotatably mounted and are arranged axially in the position of the support rollers of the respective Lynetten.
4. d) For carrying out lubricant and / or cooling lubricant and / or cooling water, the mandrel bar is preferably designed as a hollow body, so that piping and / or hoses for the required media can be installed in the cavity.

8. Main drive

To realize high drive power at high speeds, it is particularly useful to use several small and dynamic motors in association. Due to the electrical coupling as a dressing, these can be operated as a kind of drive. Through a gear reduction, the drive unit can still provide a significantly higher torque available. The gear reduction is preferably carried out by a low-cost belt drive and / or gear set, such as low-backlash planetary gear. For further increase in performance, the use of air-cooled or water-cooled engines is advantageous. In order to transmit extremely high torques from the individual drives to the main spindle, it is particularly advantageous to initiate the torque at several points distributed around the circumference with as little force as possible with just one gear step.

Fig. 1:

eine schematische Seitenansicht einer ersten Ausführungsform einer erfindungsgemäßen Vorrichtung zum Umformen eines rohrförmigen Werkstücks;

Fig. 2:

eine Schnittansicht entlang der Linie A-A von Fig. 1 und

Fig. 3:

eine schematische Seitenansicht einer zweiten Ausführungsform einer erfindungsgemäßen Vorrichtung zum Umformen eines rohrförmigen Werkstücks.

The invention will be further described below with reference to a preferred embodiment, which is illustrated in the accompanying figures:

Fig. 1:

a schematic side view of a first embodiment of a device according to the invention for forming a tubular workpiece;

Fig. 2:

a sectional view taken along the line AA of Fig. 1 and

3:

a schematic side view of a second embodiment of a device according to the invention for forming a tubular workpiece.

Fig. 1 shows an inventive device 80 for counter-rolling rollers. The apparatus 80 includes a machine bed 82, a headstock 84, a support 86, and a tailstock 60.

The headstock 84 is mounted on the machine bed 82 axially movable. For axial movement of the headstock 84, a spindle drive 98 is provided.

For clamping a first axial end 12 of a workpiece 10, a first chuck 94 is provided on the headstock 84. The chuck 94 may be rotationally driven.

On the headstock 84, a spinning mandrel 18, in particular axially displaceable and / or rotatable, is also mounted. For axial movement, an axial drive can be provided. For rotary driving, a rotary drive 92 may be provided.

The spinning mandrel 18 comprises a mandrel portion 20, which forms the actual forming mandrel, and a feed rod or mandrel 34 arranged in an axial extension of the mandrel portion 20. The mandrel bar 34 is connected to the spinning mandrel 18 via a print head 90. The printhead 90 disposed between the mandrel bar 34 and mandrel portion 20 causes a rotational decoupling between the mandrel bar 34 and mandrel portion 20. At the end of the mandrel 34 for axial displacement of the mandrel portion 20 and the mandrel 34, an axial drive 88 is arranged with anti-rotation.

On the support 86, one or more forming rollers 40 or rollers about a rotational axis 42 are rotatably mounted. The axis of rotation 42 runs skewed to a longitudinal axis 32 of the spinning mandrel 18. The support 86 may be fixedly connected to the machine bed 82.

Between headstock 84 and support 86 as well as behind the support 86 support means or Lynetten 96 may be arranged to support the workpiece 10.

The tailstock 60 is disposed to receive and support a second axial end 14 of the workpiece 10 behind the support 86. The tailstock 60 is mounted axially movable on the machine bed 82. On the tailstock 60 is a receptacle 61 for the workpiece 10, in particular the second axial end 14 of the workpiece 10, is provided. The example, sleeve or tub-shaped receptacle 61, the workpiece 10 axially movable freely.

But it is also possible that the receptacle 61 comprises a second chuck 62, in which the second axial end 14 of the workpiece 10 is clamped. For rotationally driving the second chuck 62, a rotary drive 64 is provided. For axial movement of the tailstock 60 along the machine bed 82, an axial drive 66 is arranged.

For forming the workpiece 10, the forming rollers 40 are delivered radially. As soon as the forming rollers 40 press the workpiece 10 onto the mandrel section 20, the mandrel section 20 is set in rotation by frictional engagement between the forming roller 40 and the workpiece 10. The printhead 90 prevents the mandrel bar 34 from rotating.

By axial movement of the headstock 84, the workpiece 10 clamped to the headstock 84 can be moved axially. This is particularly advantageous in the processing of long workpieces 10, for example for the production of lampposts, and shortens the overall construction length of the device 10.

Fig. 2 shows a cross-sectional view through the in Fig. 1 illustrated device 80 along the section line AA. On the support 86 four driven forming rollers 40 are arranged radially and axially movable on a holder 87.

In Fig. 3 Another device 80 for counter-rolling is shown. In this embodiment, the support 86 is arranged axially movable on the machine bed 82 and the headstock 84 fixed to the machine bed 82. On the support 86, the forming rollers 40 are mounted radially movable.

Behind the support 86 is analogous to Fig. 1 a tailstock 60 is provided.

With the device according to the invention, tubular workpieces can be transformed particularly economically and precisely overall.

Claims (12)

1. Device for forming a tubular workpiece (10) having

   - a machine bed (82),

   - a headstock (84) supported on the machine bed (82),

   - a spinning mandrel (18) supported on the headstock (84) for receiving the tubular workpiece (10),

   - a clamping chuck (94) supported on the headstock (84) for clamping a first axial end (12) of the tubular workpiece (10) and

   - at least one forming roller (40) for forming the tubular workpiece (10) arranged around the spinning mandrel (18),

   - a tailstock (60), on which a receiving part (61) for receiving and holding the second axial end (14) of the tubular workpiece (10) is provided,

   characterized in that
   the tailstock (60) is supported in an axially displaceable manner on the machine bed (82).
2. Device according to claim 1,
   characterized in that
   the receiving part (61) has a second clamping chuck (62) for clamping the second axial end (14) of the tubular workpiece (10).
3. Device according to claim 2,
   characterized in that
   the second clamping chuck (62) is supported in a rotatable manner on the tailstock (60) and can be set into rotation by the workpiece (10).
4. Device according to claim 2 or 3,
   characterized in that
   a rotary drive (64) for driving the second clamping chuck (62) in a rotating manner is provided.
5. Device according to any one of claims 1 to 4,
   characterized in that
   the tailstock (60) is supported in a freely displaceable manner on the machine bed (82).
6. Device according to any one of claims 2 to 5,
   characterized in that
   an axial drive (66) is provided for axial movement of the tailstock (60) together with the second clamping chuck (62), in particular for drawing the workpiece (10).
7. Device according to any one of claims 1 to 6,
   characterized in that
   on the tailstock (60) a mandrel for receiving formed material of the tubular workpiece (10) is provided.
8. Device according to any one of claims 1 to 7,
   characterized in that
   the spinning mandrel (18) has a mandrel section (20) at the end which is supported in a rotatable manner on a mandrel bar (34) and
   in that an axially and/or radially movable propping means (96) for propping up the mandrel bar (34) and/or the workpiece (10) is provided.
9. Device according to any one of claims 1 to 8,
   characterized in that
   a guide means for axially guiding a region of the tubular workpiece (10) is provided.
10. Device according to claim 9,
    characterized in that
    the guide means surrounds the tubular workpiece (10) annularly.
11. Device according to claim 9 or 10,
    characterized in that
    the guide means has rotatably supported sliding and/or guide jaws.
12. Method for forming a tubular workpiece (10), with a device according to any one of claims 1 to 11, having

    - a machine bed (82),

    - a headstock (84) supported on the machine bed (82),

    - a spinning mandrel (18) which is supported on the headstock (84) and on which the tubular workpiece (10) is received,

    - a clamping chuck (94) which is supported on the headstock (84) and with which a first axial end (12) of the tubular workpiece (10) is clamped,

    - at least one forming roller (40), with which the tubular workpiece (10) arranged around the spinning mandrel (18) is formed, and

    - by means of a receiving part (61) on a tailstock (60) the second axial end (14) of the tubular workpiece (10) is received and held,

    characterized in that
    during forming the tailstock (60) with the receiving part (61) is displaced axially on the machine bed (82).

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