Flow forming apparatus and flow forming method

Abstract

The invention relates to a flow forming apparatus and a method for flow forming a substantially rotationally symmetric workpiece having a drum-shaped periphery, the flow forming apparatus comprising: a spindle which can be driven in rotation about a spindle axis, a clamping device arranged on the spindle and having a number of clamping elements, the clamping elements being adjustable between a clamping position, in which the clamping elements abut against an outer peripheral region of the workpiece with a predefined clamping force and hold the workpiece on the spindle for forming, and a release position, in which the clamping elements are moved away from the workpiece in a defined manner by a first actuating device to release the workpiece from the spindle, the clamping device being able to apply a clamping force for holding the workpiece on the spindle during forming by the first actuating device, and a number of forming rollers which can be radially and axially fed to the drum-shaped periphery of the workpiece for forming the drum-shaped periphery. According to the invention, a second actuating device is provided in the clamping device, by means of which the position of the clamping element can be set in the radial direction to suit the diameter of the workpiece, and a control device is provided, by means of which the second actuating device can be actuated depending on the diameter of the workpiece to be formed, and the clamping element is pre-positioned in the radial direction depending on the diameter of the workpiece.

Description

[Technical Field]

[0001] The present invention relates to a flow forming apparatus for flow forming a substantially rotationally symmetrical workpiece having a drum-shaped periphery according to the preamble of claim 1, comprising: a spindle which can be driven in rotation about a spindle axis; a clamping device arranged on the spindle and having a plurality of clamping elements, the clamping elements being adjustable between a clamping position in which the clamping elements abut against the outer circumferential region of the workpiece with a predetermined clamping force and hold the workpiece on the spindle for forming, and a release position in which the clamping elements are moved away from the workpiece in a defined manner to release it from the spindle, the clamping device being able to apply a clamping force to hold the workpiece on the spindle during forming by the first actuation device; and a plurality of forming rollers which can be fed radially and axially around the drum-shaped periphery of the workpiece for forming the drum-shaped periphery.

[0002] The invention further relates to a flow-forming method according to the preamble of claim 18. [Background technology]

[0003] During flow forming of workpieces, particularly for the production of vehicle wheels, a disk- or pot-shaped workpiece is rotated to vary the wall thickness of the starting workpiece, thereby forming a drum-shaped wall region. During this operation, significant axial and circumferential forces are generated in the workpiece. To securely hold the workpiece in place on the spindle as it is rotated, a clamping device capable of exerting a sufficiently large clamping force on the workpiece must be provided on the drive spindle. The processing forces generated in a flow forming apparatus can be many times greater than those that can be generated, for example, on a lathe for machining materials.

[0004] In flow forming, to apply the clamping force required to hold the workpiece in the correct position on the spindle, it is known to press the workpiece axially against the spindle, usually by means of a counterholder, where the large axial clamping force can be applied by an axially acting hydraulic cylinder.

[0005] However, when the workpiece is axially clamped in the flow forming apparatus by the counterholder, the internal space within the wall of the drum-shaped workpiece to be formed is completely or at least partially occupied, which means that the occupied internal space cannot be used as a processing space.

[0006] EP3351313A1 describes a general type of flow forming apparatus in which an internal space for feeding inner forming rollers is required for forming vehicle wheels. The flow forming apparatus generally describes a drum-shaped workpiece area formed between at least one inner roller and at least one associated outer roller. A clamping device having outer clamping jaws is provided for clamping the workpiece, and the outer clamping jaws hold the workpiece at its radially outer edge during flow forming. The clamping jaws have a linear displacement path and an actuating device, which allows the clamping jaws to be adjusted between a release position and a clamping position for holding the workpiece. The actuating device adjusts the clamping jaws to apply the required clamping force to the workpiece and hold it on the spindle.

[0007] In this type of clamping device, the clamping travel needs to be set as small as possible to ensure efficient clamping with the desired large clamping force. In particular, when the outer diameter of the workpiece changes, the clamping device needs to be readjusted with respect to the corresponding feed and clamping paths. Summary of the Invention [Problem to be solved by the invention]

[0008] The object underlying the present invention is to provide a flow-forming device and a method for flow-forming a workpiece, which allows a particularly efficient processing of the workpiece. [Means for solving the problem]

[0009] According to the invention, this object is achieved on the one hand by a device having the features of claim 1 and on the other hand by a method having the features of claim 18. Preferred embodiments of the invention are set out in the dependent claims. The invention in principle also includes a method for flow forming a workpiece using such a flow forming device.

[0010] The flow forming apparatus according to the present invention is characterized in that a second actuating device is provided in the clamping device, by means of which the position of the clamping element can be set radially to suit the diameter of the workpiece, and a control device is provided, by means of which the second actuating device can be actuated according to the diameter of the workpiece to be formed, and the clamping element is pre-positioned radially according to the diameter of the workpiece.

[0011] The basic concept of the present invention is to provide a flow forming apparatus having a clamping device, the clamping device having a first actuating device for adjusting the clamping element, the first actuating device always ensuring the same or substantially the same adjustment path of the clamping element so that the desired clamping force is achieved by the first actuating device after the intended adjustment path of the clamping element. Additionally, the clamping device of the flow forming apparatus according to the present invention has a second actuating device, which allows the prepositioning of the clamping element in the radial direction to be set to match the diameter of the workpiece. This prepositioning is automatically controlled by a control device, which activates the second actuating device based on information about the workpiece to be processed, in particular the diameter of the workpiece to be formed, thus providing an appropriate prepositioning of the clamping element for the actual clamping movement by the first actuating device.

[0012] The present invention not only ensures particularly good clamping on the outside of the workpiece, but also ensures that the workpiece can be flow formed with high forming forces. Pre-positioning also reduces the time required for the actual clamping of the workpiece, thereby reducing the proportion of non-productive time during the processing of the workpiece. This improves the utilization of the equipment and reduces costs.

[0013] An additional advantage of the present invention is that high processing flexibility can be achieved by automatically prepositioning the clamping elements by the second actuating device via the control device. Therefore, multiple workpieces with different diameters can be efficiently flow formed in almost any order without time-consuming modifications to the clamping device. It is preferable to activate the second actuating device only when there is a change in the type of workpiece, i.e., when processing workpieces with different starting dimensions and diameters.

[0014] A preferred embodiment of the invention is that the clamping elements are adjustable axially and / or radially between a clamped position and a released position by the first actuating device. In particular, the clamping elements are first radially and then axially fed by the first actuating device, and the actual clamping force is generated solely or to a significant extent by the axial movement of the clamping elements. This allows the workpiece to be pressed against the spindle and held thereon with particular reliability.

[0015] In principle, the actuating device can be configured in any way, for example by a recirculating ball screw. According to a further development of the invention, particularly large actuating forces can be realized in that the first actuating device has at least one actuating cylinder, preferably hydraulically operated. The actuating cylinder can generate the required clamping force by itself or in combination with at least one further force-generating element, such as a disk spring assembly.

[0016] The overall clamping force can be further increased in that each clamping element is assigned an actuating cylinder by means of which the adjusting elements can be displaced between a clamped position and a released position, in which the clamping elements are each spaced to a certain extent from the workpiece so that the workpiece can be removed from the spindle and a new workpiece can be inserted.

[0017] In principle, individual clamping elements may be provided on displaceable carriages for pre-positioning. According to a further development of the invention, it is particularly suitable for each clamping element to be mounted eccentrically with respect to the disk axis on a rotatable disk, the disk axis being oriented parallel to the spindle axis, and for the second actuating device to comprise an actuator for rotating the disk together with the clamping element. In principle, a rotating actuator can be assigned to each rotatable disk. It is particularly advantageous for a single actuator, in particular an adjusting wheel, to be provided for rotating all disks. The adjusting wheel can be controlled and actuated via a corresponding drive pinion of the second actuating device. In principle, the flow forming apparatus may be provided with a horizontally oriented spindle axis.

[0018] Alternatively, according to one embodiment of the present invention, it is preferred here that the clamping elements are mounted on a radially displaceable or pivotable carriage, and the second actuating device is configured to radially displace or pivot the carriage. An actuating cylinder for displacing and clamping the respective clamping element may be arranged on the carriage.

[0019] According to a further development of the invention, a particularly compact design is realized in that the spindle axis is arranged vertically and the clamping device is arranged suspended relative to the spindle, allowing the workpiece to be clamped from below. Such vertical suspension of the workpiece particularly facilitates the removal of the workpiece by an automatic loading and unloading device, in particular a manipulator arm and / or a robot. Once the clamping device is released, the workpiece can be easily removed downwards, preferably by the same manipulator and / or robot.

[0020] According to a further preferred embodiment of the present invention, at least one outlet is provided and a suction device is provided, which can advantageously suck air and / or smoke through the at least one outlet. The outlet can preferably be provided in the area of ​​the clamping device, particularly in the case of a suspended arrangement. Via one or more outlets, vapors, particularly containing oil or coolant components, can be efficiently removed from the working chamber and fed to a separation device and / or recycling device for recovering the cooling and lubricating fluid.

[0021] According to one embodiment of the present invention, processing is further improved in that a central centering pin, preferably configured for elastic and / or flexible centering, is arranged in the clamping device to ensure accurate centering of workpieces with different inner diameters, thereby enabling a reliable and gentle centering of the workpiece on the spindle before or during clamping.

[0022] According to a variant of an embodiment of the present invention, a particularly efficient processing flow is realized in that a control device for supplying data about the workpiece, in particular data about the diameter of the workpiece, is connected to the control station and / or to at least one sensor for detecting the workpiece using the diameter. Via the central control station, the flow forming apparatus can be constantly supplied with information about the type of workpiece currently to be processed. In the case of chaotic production involving a large number of possible pre-processing stations, the type of workpiece, in particular its diameter, can be detected by at least one sensor connected to the control device. Depending on the supplied data, a second actuation device for pre-positioning the clamping element, if necessary, can be actuated via the control device.

[0023] Furthermore, for flexible forming of each individual workpiece, it is advantageous for a control device to control the movement of the forming rollers during forming. Thus, depending on the type of workpiece to be processed, the forming rollers can be displaced in a defined manner by the control device to form the desired wall thickness profile and desired workpiece contour. In this way, flexible and efficient production of fewer or more individual workpieces can be realized using the flow forming apparatus according to the present invention.

[0024] In particular, a further development of the flow-forming apparatus according to the invention provides particularly high flexibility in that at least one outer forming roller and at least one inner forming roller are provided, which respectively abut against the outer and inner peripheries of the drum-shaped periphery of the workpiece and are axially and radially adjustable relative to one another by a control device and / or the pitch angle of at least one inner forming roller is variable in order to form and create wall thickness profiles with varying wall thicknesses. In this way, individual contours and wall thickness profiles can be produced for almost any individual workpiece with the same efficiency as mass production.

[0025] In another preferred embodiment of the present invention, two interchangeable spindles are provided, with the first one positioned in the working chamber and the second one positioned in a loading and / or unloading position, and the two interchangeable spindles are alternately movable relative to each other. The two interchangeable spindles may be reversibly displaceable, so that the two interchangeable spindles alternate between a working position in the working chamber and one of two loading and / or unloading positions for loading or unloading the workpiece. For example, a turret mechanism may be provided. The individual interchangeable spindles may also have different loading and unloading positions, from which each interchangeable spindle is subsequently displaced into its respective working chamber. This allows for rapid loading and / or unloading, thus resulting in faster overall processing times.

[0026] According to a further development of the invention, it is advantageous to provide a measuring device by means of which dimensions and data relating to the processing of the workpiece can be determined before and / or after forming. The measuring device can in particular comprise an optical sensor and / or a thermal sensor for determining the workpiece. The measuring device in particular communicates with the control device.

[0027] As a rule, flow forming machines are designed for cold forming processes. For certain processes, it may be advantageous to provide at least one cooling device and / or one thermal protection device for semi-hot and / or hot forming of the workpiece. In particular, for the formation of light metal wheels, targeted temperature control of the workpiece can be achieved and adjusted in this way. In hot forming, the temperature of the workpiece blank can also be measured by a pyrometer or temperature sensor before the workpiece blank is introduced into the working area of ​​the flow forming machine.

[0028] Preferably, the rollers of the inner and outer supports are configured as standard, general-purpose rollers for the flow forming apparatus. However, specific wheel or wheel hub shapes may require roller modifications. Further improvement in the flexibility of the flow forming apparatus according to the present invention can be realized by providing quick-release clamping devices on the inner and / or outer supports of the outer forming rollers and / or at least one bearing of at least one inner forming roller, allowing semi-automatic or fully automatic roller changes. The roller shape can be efficiently adapted to the corresponding contour path of a specific workpiece. This further increases the variety of workpiece shapes that can be realized by the flow forming apparatus.

[0029] For targeted temperature control during forming, it may also be useful for the workpiece to have a different temperature in the forming area than in the clamping and / or centering areas. The spoke areas preferably have a lower temperature than the forming area. In particular, a higher temperature may be provided in the forming area or working area of ​​the workpiece, where the forming rollers engage.

[0030] The invention relates in particular to a method for flow forming a substantially rotationally symmetrical workpiece having a drum-shaped periphery, using one of the flow forming apparatuses mentioned above, in which the workpiece is clamped to a spindle by a clamping device, the clamping device having a plurality of clamping elements, the clamping elements being adjustable between a clamping position in which the clamping elements abut against an outer peripheral region of the workpiece with a predetermined clamping force and hold the workpiece on the spindle for forming, and a release position in which the clamping elements are moved away from the workpiece in a defined manner by a first actuating device to release the workpiece from the spindle, for holding the workpiece on the spindle during forming. a clamping force of 0.01 MPa is applied by a first actuating device, the spindle is driven in rotation about the spindle axis, and a plurality of forming rollers are fed radially and axially onto the workpiece for forming the drum-shaped periphery, in particular a second actuating device is provided on the clamping device, by means of which the position of the clamping elements is adapted to the diameter of the workpiece and the clamping elements are adjusted radially, and a control device is provided, by means of which the second actuating device is actuated depending on the diameter of the workpiece to be formed and the clamping elements are radially pre-positioned depending on the diameter of the workpiece.

[0031] A particularly energy-efficient flow forming apparatus has a recovery option when braking at least one main spindle with a chuck. Despite the lightweight design of the chuck, a significant mass must be accelerated or decelerated. It is preferable to use the recovered energy of the first exchangeable spindle to accelerate the energy storage mass of the second exchangeable spindle and / or flywheel. Alternatively, energy recovery through net regenerative feedback is also possible.

[0032] To specifically enhance the availability of the flow forming apparatus, an apparatus having two interchangeable spindles can also be economically operated as a single spindle apparatus. In the event of low capacity utilization, raw material shortages, maintenance or failure of the interchangeable spindle, and / or failure of upstream and / or downstream lines or systems, the flow forming apparatus can continue to operate with only one spindle.

[0033] The invention will be explained in more detail below with reference to preferred exemplary embodiments which are illustrated diagrammatically in the drawings. [Brief explanation of the drawings]

[0034] [Figure 1] 1 is a perspective view of a flow forming apparatus according to the present invention without the protective housing and the loading and unloading device. [Figure 2] 1 is an enlarged view of a clamping device of a flow forming apparatus according to the present invention, showing a clamped workpiece in cross section. [Figure 3] FIG. 3 is an enlarged, partially cross-sectional, detailed perspective view of the clamping device according to FIG. 2. [Figure 4] FIG. 4 is another enlarged, partially cross-sectional, detailed perspective view of the adjustment mechanism of the clamping device according to FIGS. 2 and 3. [Figure 5] FIG. 10 is a cross-sectional view of an alternative clamping device of a flow forming apparatus according to the present invention. [Figure 6] Figure 5 is a top view of the clamping device. [Figure 7] FIG. 7 is a perspective view of the clamping device according to FIGS. 5 and 6. [Figure 8] FIG. 8 is another cross-sectional view of the clamping device according to FIGS. 5 to 7, in which the clamping element is shown in the release position in the right half. [Figure 9] FIG. 9 is another cross-sectional view of the clamping device according to FIGS. 5 to 8, with the intermediate position during clamping shown in the right half. DETAILED DESCRIPTION OF THE INVENTION

[0035] The flow forming apparatus 10 according to the present invention and shown in Figure 1 has a base frame 12 including three vertical columns 14 surrounding a working chamber. Two rotary drive spindles 20 are mounted on the plate-like cover area 16 and are linearly slidable by linear drives 22, alternately movable between an outer loading and unloading position and a central working position.

[0036] A clamping device 40 for lifting and holding the workpiece 5 in a suspended position is provided on the underside of each spindle 20 facing downwards towards the working chamber. Claw-like clamping elements 50 distributed along the periphery are arranged on the drum-like clamping device 40 for clamping the workpiece 5, as will be explained in more detail below.

[0037] Each of the vertical columns 14 is provided with a radially and vertically adjustable forming roller 30, which may in principle also be angled, with the outer forming rollers 30a rotatably mounted on an outer support 34 and the inner forming rollers 30b rotatably mounted on an inner support 38. As clearly shown in FIG. 2, the inner rollers 30b are configured to advance within the interior space of the workpiece 5, while the outer rollers 30a are configured to machine the outer periphery of the workpiece 5. The outer rollers 30a and the inner rollers 30b are displaceable in the axial and radial directions.

[0038] According to Fig. 2, a drum-shaped workpiece 5, in particular a cast or forged blank of a vehicle wheel, is clamped in and suspended from a clamping device 40. The workpiece 5 has a hub 6 with a central hole into which a centering pin 44 of the clamping device 40 engages for centering purposes. For pressure and form-fit retention, several claw-like clamping elements 50 are fed onto the radially outer upper edge of the workpiece 5, which presses the workpiece 5 axially against the clamping device 40.

[0039] The outer and inner forming rollers 30a, 30b are fed in pairs relative to one another to the drum-shaped periphery 7 of the workpiece 5 and can be displaced radially and / or axially relative to one another to set a forming gap, allowing flow forming of the drum-shaped periphery 7 and forming individual wall thickness profiles with varying wall thicknesses. In particular, thick humps and rim flanges for receiving vehicle tires can be formed in the drum-shaped periphery 7.

[0040] 3 and 4, the structure of the clamping device 40 of the flow forming apparatus 10 according to the present invention will be explained in more detail below. The drum-shaped clamping device 40 has a substantially pot-shaped housing 42 in which a first actuating device 60 is provided for axially adjusting the claw-shaped clamping element 50 in a vertical clamping direction. To move the clamping element 50 between a lower release position and an upper clamping position, the clamping element 50 is arranged on a lifting shaft 52 connected to an actuating cylinder 62 and / or a lifting plate 64.

[0041] In the clamping position, the workpiece 5 is pressed upward by the clamping elements 50 against the corresponding counterholders 54, which are attached together with the respective clamping elements 50 to plate-shaped disks 74 of the second actuation device 70. The disks 74 have external teeth that are connected via intermediate gears 76 to a central actuator 78 configured as an external gear. The rotational movement of the central actuator 78 is transmitted to the respective disks 74 via the intermediate gears 76. The clamping elements 50, each with a lifting axis 52, are attached to the disks 74 eccentrically with respect to the disk axis 72. The rotational movement thus changes the radial distance between the clamping elements 50 and the central axis of rotation, so that radial pre-positioning of the clamping elements 50 to adapt to changes in the diameter of the workpiece 5 can be easily performed by adjusting the central actuator 78.

[0042] Along the periphery of the central actuator 78, a number of discs 74 each having a clamping element 50 and a counter holder 54 are arranged to clamp the workpiece 5 uniformly along the periphery.

[0043] For axial clamping, a clamping force is generated by the respective actuating cylinders 62 of the clamping elements 50 and / or the lifting plates 64, which can be activated by an axial lifting mechanism (not shown) for uniform actuation of all clamping elements 50. A spring device 68 at the upper end of the lifting shaft 52 can be used to preload and compensate for thickness differences. In principle, an additional axial clamping force for clamping the workpiece 5 can also be applied via the spring clamping device 68.

[0044] For the concentric movement of the clamping elements 50 and the counterholder 54 , radial groove-like guides are provided in the guide disc 65 of each clamping element 50 .

[0045] For adjustment of the central diameter, a central adjusting element with position detection is provided above the drive spindle 20, which is connected via a drive shaft to a multi-spline coupling 79 and can counteract the corresponding adjusting force of the clamping element 50 and the centrifugal force.

[0046] An alternative clamping device 40 for the flow forming apparatus 10 according to the present invention is shown in FIGS. 5 to 9. According to FIG. 5, the clamping device 40 has a drum-shaped base body on the end face of which a plurality of clamping elements 50, specifically eight clamping elements 50, are distributed around the circumference of the workpiece 5 for clamping the workpiece 5. Each clamping element 50 is adjustable with an associated actuating cylinder 62 on a plate-shaped carriage 73 parallel to the central axis of rotation. The carriage 73 is mounted for radial displacement along a radially oriented guide groove in the drum-shaped base body. A central centering pin 44 is provided for centering the workpiece 5 and can axially enter a corresponding central opening in the workpiece 5.

[0047] To clamp the workpiece 5, the clamping element 50 is first in the release position, which is shown diagrammatically in the right half of Fig. 8. In this release position, the carriage 73 of the second actuating device is displaced radially outward. At the same time, the clamping element 50 is displaced axially upward by the actuating cylinder 62, as shown in Fig. 8.

[0048] When all clamping elements 50 are in this release position, the workpiece 5 can be positioned and centered concentrically with respect to the axis of rotation by means of the centering pin 44 .

[0049] The carriage 73 is displaced radially inwards, preferably by an actuating cylinder (not shown), and more particularly via a second actuating device (not shown), until the clamping elements 50 come into radial contact with the workpiece 5. This is clearly shown in the right half of Figure 9.

[0050] Starting from this pre-positioning by the second actuating device using the carriage 73, the workpiece 5 can be firmly clamped by the clamping element 50, as shown clearly in Figures 5 to 7. For this purpose, the clamping element 50 is displaced downwards via the actuating cylinder 62, so that the workpiece 5 is pressed against the base body of the clamping device 40 and firmly clamped. To release the workpiece 5, the clamping element 50 can be displaced in the reverse order to the initial or release position according to Figure 8.

[0051] Also in this variant of the invention, the prepositioning of the clamping element 50 can be carried out by a second actuating device, preferably by means of a radially linearly displaceable carriage 73. This allows the clamping device to efficiently clamp onto workpieces 5 with different outer diameters.

[0052] In principle, the clamping or centering pin 44 may alternatively be configured as a jaw chuck, which may clamp onto an internal bore and / or clamp externally onto the sprue pin of the casting blank.

[0053] In principle, the clamping element 50 may alternatively be fed axially relative to the workpiece 5 so as to clamp by a pivoting movement.

Claims

1. 1. A flow forming apparatus for flow forming a substantially rotationally symmetric workpiece having a drum-shaped periphery, comprising: a spindle that can be driven in rotation about its spindle axis; a clamping device arranged on the spindle and having a plurality of clamping elements, the clamping elements being adjustable by a first actuating device between a clamping position in which the clamping elements abut against the outer peripheral region of the workpiece with a predetermined clamping force, holding the workpiece on the spindle for forming, and a release position in which the clamping elements are moved away from the workpiece in a defined manner to release the workpiece from the spindle, the clamping force for holding the workpiece on the spindle during forming being exerted by the first actuating device; a plurality of forming rollers radially and axially feedable onto the drum-shaped peripheral portion of the workpiece for forming the drum-shaped peripheral portion of the workpiece, a second actuation device is provided on the clamping device, by means of which the position of the clamping element can be set in the radial direction to suit the diameter of the workpiece; a control device is provided by which the second actuation device can be actuated as a function of the diameter of the workpiece to be formed, and the clamping elements are pre-positioned in the radial direction as a function of the diameter of the workpiece.

2. The flow forming apparatus of claim 1 , wherein the clamping element is adjustable in the axial direction between the clamped position and the released position by the first actuation device.

3. The flow forming apparatus of claim 1 , wherein the first actuating device comprises at least one hydraulically operated actuating cylinder.

4. 4. The flow forming device according to claim 3, characterized in that each clamping element is assigned an actuating cylinder by means of which said clamping elements can be displaced between said clamping position and said release position, respectively.

5. each clamping element is mounted on a rotatable disk eccentrically with respect to a disk axis, the disk axis being oriented parallel to the spindle axis; The flow forming apparatus of claim 1 , wherein the second actuation device comprises an actuator for rotating the disk together with the clamping element.

6. each clamping element is mounted on said radially displaceable or pivotable carriage; The flow forming apparatus of claim 1 , wherein the second actuation device is configured to displace or pivot the carriage in the radial direction.

7. The spindle axis is vertically disposed; the clamping device is positioned suspended from the spindle; 2. The flow forming apparatus according to claim 1, wherein the workpiece can be clamped from below.

8. at least one outlet is provided; 2. The flow forming apparatus according to claim 1, further comprising a suction device, which is capable of sucking air and / or smoke through said at least one outlet.

9. 2. The flow forming apparatus according to claim 1, characterized in that a central centering pin, which is configured to be elastic and / or flexible, is arranged on the clamping device.

10. 2. The flow forming apparatus according to claim 1, characterized in that the control device for supplying data relating to the workpiece, in particular data relating to the diameter of the workpiece, is connected to a control station and / or to at least one sensor for identifying the workpiece using the diameter of the workpiece.

11. 2. The flow forming apparatus of claim 1, wherein the control device controls the movement of the forming rollers during forming for flexible forming of each individual workpiece.

12. At least one outer forming roller and at least one inner forming roller are provided, the at least one outer forming roller and the at least one inner forming roller abutting the outer and inner peripheries of the drum-shaped periphery of the workpiece and being adjustable in the axial and radial directions relative to one another by the control device to form and create a wall thickness profile with a varying wall thickness, and / or the pitch angle of the at least one inner forming roller is variable. The flow forming apparatus according to claim 1, wherein:

13. 2. The flow forming apparatus according to claim 1, characterized in that two interchangeable spindles are provided, a first interchangeable spindle being located in the working chamber while a second interchangeable spindle is located in the loading position and / or the unloading position, the two interchangeable spindles being alternately displaceable relative to each other.

14. 2. A flow forming apparatus according to claim 1, characterized in that a measuring device is arranged therein, by means of which dimensions and data relating to the processing of the workpiece can be determined before and / or after forming.

15. 2. A flow forming apparatus according to claim 1, characterized in that at least one cooling device and / or one thermal protection device is provided for semi-hot forming and / or hot forming of the workpiece.

16. 2. The flow forming apparatus according to claim 1, characterized in that quick-release clamping devices are arranged on the inner and / or outer supports at the bearings of at least one outer forming roller and / or at least one inner forming roller, said quick-release clamping devices enabling semi-automatic or fully automatic roller changing.

17. 10. The flow forming apparatus of claim 1, wherein the workpiece has a different temperature in the forming region than in the clamping and centering regions.

18. 1. A method for flow forming a substantially rotationally symmetrical workpiece having a drum-shaped periphery, in particular using a flow forming device as claimed in claim 1, comprising: - the workpiece is clamped to the spindle by a clamping device, the clamping device having a plurality of clamping elements, the clamping elements being adjustable between a clamping position in which the clamping elements abut a peripheral region of the workpiece with a predetermined clamping force to hold the workpiece on the spindle for forming, and a release position in which the clamping elements are moved away from the workpiece in a defined manner to release the workpiece from the spindle, the clamping force for holding the workpiece on the spindle during forming being applied by a first actuation device; - said spindle is driven in rotation about its spindle axis, - forming rollers are fed radially and axially onto the workpiece for forming the drum-shaped periphery, a second actuation device is provided on the clamping device, by means of which the position of the clamping elements is adapted to the diameter of the workpiece and the clamping elements are set in the radial direction; a control device is provided, by means of which the second actuation device is actuated as a function of the diameter of the workpiece to be formed, and the clamping element is pre-positioned in the radial direction as a function of the diameter of the workpiece.

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