Device and method for shaping a metal hollow cylindrical end section of a workpiece

Abstract

The invention relates to a device for forming an end section of a workpiece into a radially inwardly turned collar, comprising a clamping device for clamping the workpiece along a clamping axis, a rotationally symmetrical forming tool having a concavely curved forming face facing the clamping device, from the center of which a coaxial pin protrudes, a feed device by means of which the clamping device and the forming tool can be moved toward one another along the clamping axis, and a rotation device by means of which the clamping device and the forming tool can be rotated relative to one another, wherein the feed device and the rotation device are controllable in a combined feed process and rotation process, in which the feed device moves the clamping device and the forming tool toward one another along the clamping axis and simultaneously the rotation device rotates the clamping device and the forming tool relative to one another. The invention is characterized in that the azimuth angle between the clamping axis and the axis of symmetry of the forming tool is variable during the combined feed process and rotation process.

Description

TECHNICAL FIELD

[0001] The invention relates to a device for forming a metal hollow-cylindrical end section of a workpiece into a radially inwardly turned Kragen, comprising

[0002] - a clamping device for clamping the workpiece along a clamping axis, which clamping axis in the clamped state of the workpiece is identical to the workpiece axis, i.e. the cylinder axis of the hollow-cylindrical end section of the workpiece,

[0003] - a forming tool which is rotationally symmetrical about a symmetry axis, which forming tool has a concavely curved forming face facing the clamping device, from the center of which forming face a coaxial pin projects, which coaxial pin has a shank and a base, which base widens from the shank towards the forming face and continuously transitions on the one hand into the curvature of the forming face and on the other hand into the shank,

[0004] - a feed device by means of which the clamping device and the forming tool can be moved towards one another along the clamping axis, and

[0005] - a rotation device by means of which the clamping device and the forming tool can be rotated relative to one another,

[0006] wherein the feed device and the rotation device can be actuated in a combined feed process and rotation process, wherein the feed device moves the clamping device and the forming tool towards one another along the clamping axis and simultaneously the rotation device rotates the clamping device and the forming tool relative to one another.

[0007] The invention furthermore relates to a method for forming a metal hollow-cylindrical end section of a workpiece into a radially inwardly turned Kragen, comprising the following steps:

[0008] - clamping the workpiece along the workpiece axis, i.e. the cylinder axis of the hollow-cylindrical end section of the workpiece, so that the hollow-cylindrical end section faces a concavely curved forming face of a forming tool which is rotationally symmetrical about a symmetry axis, from the center of which forming face a coaxial pin projects, which coaxial pin has a shank and a base, which base widens from the shank towards the forming face and continuously transitions on the one hand into the curvature of the forming face and on the other hand into the shank,

[0009] - carrying out a combined feed process and rotation process, wherein the workpiece and the forming tool are moved towards one another along the workpiece axis and simultaneously the workpiece and the forming tool are rotated relative to one another,

[0010] wherein during the combined feed process and rotation process the material of the hollow-cylindrical end section flows in succession along the curved forming face, the base and the shank in order to construct the Kragen. BACKGROUND

[0011] A device of this type and a method of this type are known from US 2,791,674 A.

[0012] On different technical fields, the task arises to turn a hollow-cylindrical end section of a metal workpiece radially inwards, in order to reduce the opening diameter of the hollow cylinder on the one hand and to make available the inner face, which was part of the outer face before the forming process, as a joining face for further components on the other hand. The above-mentioned document discloses the application of this technology in the context of the manufacture of compressed-gas bottles. Another example of application in the focus of the present invention is the manufacture of hollow-rotor shafts for electric motors, in particular for electric traction motors of motor vehicles.

[0013] The device disclosed in the above-mentioned document of this type comprises a chuck, into which a workpiece having a hollow-cylindrical end section can be clamped along the cylinder axis of the end section. This axis shall be referred to below as cylinder axis, workpiece axis or clamping axis, depending on the specific context and specific reference. The chuck is connected via a transmission with a motor, by means of which the chuck can be rotated about the workpiece axis. At the same time, a feed device is provided, by means of which the chuck together with the transmission and the motor can be linearly advanced along the workpiece axis. Arranged opposite the chuck and coaxially aligned with the chuck is a forming tool, which has a circular concave forming face open towards the chuck or the clamped workpiece. In the centre of the forming face, a concentric pin projects, which extends along the workpiece axis and whose free end faces the workpiece. In the region of the free end of the concentric pin, the pin is formed as a cylindrical shank. The pin transitions towards the forming face into a widened base. The base forms a smooth transition between the concave curvature of the forming face and the cylindrical shank. In order to form the hollow-cylindrical end section into a radially inwards turned collar, a combined feed and rotation process is carried out, in which the workpiece is rotated about its workpiece axis and at the same time advanced along the workpiece axis towards the forming tool. The actual forming process begins when the end side of the workpiece comes into contact with the concave forming face, in which the workpiece material begins to flow radially inwards along the forming face in succession. The flow direction is here always further turned radially inwards with increasing feed until the workpiece material contacts the base of the pin, where the change in direction develops into an actual reversal of direction and the workpiece material flows along the pin against the feed direction. Thereby a collar is constructed around the pin, which encloses a relatively long channel with a cylindrical inner face depending on the shape of the pin and in particular the dimensions of the shank. After the formed workpiece is released from the device, the inner face can be used as a joining face. The above-mentioned document proposes the cutting of an internal thread, in order that a pressure fitting can be screwed in. Disadvantageous in this device and this method is the enormous frictional force that arises due to the full-area contact between workpiece and forming tool and which must be overcome mechanically. The focus of the above-mentioned document is therefore on the construction of an additional heating device for the workpiece and the forming tool, which in particular allows the combustion of a lubricant on the surface of the workpiece.

[0014] From DE 10 607 010 C1 a partial forming method is known from the same context of manufacturing compressed gas bottles. There, the clamping axis of the clamped workpiece or workpiece axis and the symmetry axis of the forming tool are not coaxial, but are offset parallel to each other. Thus, during the combined feed process and the rotation process, the workpiece is only in contact with the forming surface in a relatively small angular range. Thus, with the same feed force a higher pressure is generated, which acts on the workpiece with less friction. Likewise, the contact between the workpiece material and the pin also only takes place partially, namely on the contact line between the workpiece and the side of the pin which is opposite the forming surface. Therefore, the workpiece diameter, the forming surface diameter and the pin diameter must be coordinated with each other extremely precisely in order to produce a collar with a predetermined diameter. Lower manufacturing tolerances of the workpiece or wear at the forming surface and / or the pin lead to significant dimensional accuracy problems in the produced product.

[0015] From US 2003 / 0192358 A1 a swing tool for forming the outer contour and the inner contour of a hollow cylindrical workpiece is known, wherein, however, only the hollow cylindrical end section of the workpiece is intended to be extruded, but not turned over. SUMMARY

[0016] The task of the present invention is to improve a device of this type and a method of this type in such a way that, with improved method efficiency, greater reliability with regard to dimensional accuracy of the produced product is ensured.

[0017] The task is solved in conjunction with the features of the preamble of claim 1 in that the azimuth angle between the clamping axis and the symmetry axis of the forming tool is variable during the combined feed process and the rotation process.

[0018] The task is solved in conjunction with the features of the preamble of claim 10 in that the azimuth angle between the workpiece axis and the symmetry axis of the forming tool is varied during the combined feed process and the rotation process.

[0019] First, the application employs the concept of local action forming, but in a novel way. Thus, the local action is achieved by an inclined position between the forming tool and the workpiece. For the person skilled in the art, this way is known in principle from rotary forging or swing forging. However, it does not first of all comply with the goal of creating a collar with an essentially cylindrical inner joint surface. This is achieved in that the azimuth angle (in which the clamping axis or the workpiece axis is inclined with respect to the symmetry axis of the forming tool, i.e. with respect to the pin axis) can be varied or actually varied during forming. In particular, it is provided that a control device is set up to operate the feed device and the rotation device in order to monotonously reduce the azimuth angle from a non-zero starting angle to zero during the combined feed process and rotation process. In the context of the method according to the application, this means that the azimuth angle is monotonously reduced from a non-zero starting angle to zero during the combined feed process and rotation process. This leads to the fact that during an initial phase of the forming process the interaction between the forming tool and the workpiece is largely local. However, in this initial phase the contact between the forming tool and the workpiece is essentially limited to the outer region of the forming surface. In this phase, the material of the workpiece has not yet flowed to the pin. In this regard, the inclined position of the pin with respect to the workpiece axis is harmless in this initial phase. As the forming increases, i.e. as the workpiece material flows further along the forming surface in the direction of the pin, the azimuth angle is reduced, so that the interaction between the forming tool and the workpiece becomes increasingly less local. However, the pin is simultaneously increasingly strongly transitioned into alignment coaxial with the workpiece axis. At the end of the process, when the material flow is complete, the forming tool and the workpiece are coaxial with respect to each other. The coaxial pin defines an essentially cylindrical "inner core" of the created collar, and this situation essentially corresponds to the last situation of a non-local forming method. Likewise, the method according to the application benefits from all the advantages of the only local interaction on the way to this last situation.

[0020] Thus, with the method according to the application it is possible to achieve forming with the same dimensional accuracy as in a non-local method, wherein, however, the force and lubricant expenditure required in a non-local method is not required.

[0021] However, in the context of the method according to the application, the use of lubricants is of course not excluded either, and the use of lubricants is even in many cases advantageous. Here, the person skilled in the art will have to decide individually on the basis of the requirements of the individual case. However, due to the above-mentioned effects of the way according to the application, the person skilled in the art has a wider option for his decision to use.

[0022] In order to materialize the rotational movement between the workpiece and the forming tool, two ways have proven to be particularly advantageous. Within the framework of the first way, it is provided that a wobbling movement of the forming tool about the clamping axis is generated by means of the rotating device. Here, the clamping device can be rotationally fixed during the wobbling movement. However, a slight inherent rotation of the clamping device about its clamping axis can also be envisaged. In the context of the method according to the application, this means that during the combined feeding process and the rotation process, a wobbling movement of the forming tool about the workpiece axis is carried out. Here, the workpiece can be rotationally fixed during the wobbling movement. However, a slight rotation of the workpiece about its workpiece axis can also be envisaged. In the description using spherical polar coordinates, this way thus means that the polar angle of the forming tool is changed, preferably at a constant speed, given the azimuth angle. The symmetry axis of the forming tool thus moves on a conical peripheral surface about the clamping axis or the workpiece axis, wherein, however, it should be noted that due to the reduction of the azimuth angle according to the application, the conical peripheral surface is tapered helically.

[0023] In the alternative second way, it is provided that a common, preferably synchronous, rotational movement of the clamping device about the clamping axis and of the forming tool about its symmetry axis is generated by means of the rotating device. In the context of the method according to the application, this means that during the combined feeding process and the rotation process, the workpiece and the forming tool are rotated jointly, preferably synchronously, i.e. the workpiece is rotated about its workpiece axis and the forming tool is rotated about its symmetry axis. In contrast to the wobbling way, in this rotational way, the clamping axis or the workpiece axis and the symmetry axis of the forming tool are spatially fixed relative to each other, apart from the change in the azimuth angle according to the application. The two sub-rotations of the forming tool and the workpiece are preferably carried out in the same rotational direction. Also preferably, the rotational speeds are identical, i.e. in the sense that no or at most only a very low relative speed between the workpiece and the forming tool is generated at the respective first point of contact between the material of the workpiece and the forming face.

[0024] For both ways described above, two variants have proven to be particularly advantageous. According to the first variant, the pin is rigidly connected to the forming face as a whole. In this variant, the material of the workpiece flows along the length of the pin against the feeding direction.

[0025] In a second variant, it is provided that the shank can be moved relative to the base along the axis of symmetry of the forming tool by means of a shank travel device. Here, the control device is preferably further provided to control the shank travel device to move the shank towards the clamping device during and / or after the combined feeding and rotating process. In the context of the method according to the application, this means that the shank is moved towards the workpiece during and / or after the combined feeding and rotating process. In the case where the shank travels synchronously with the flow of workpiece material during the combined feeding and rotating process, as is preferably provided, the friction between the flowing workpiece material and the shaft is minimized. Conversely, it is also conceivable that the actual turning process takes place with the shank (largely) retracted. This then firstly leads to an imprecise, in particular too narrow, dimensioning of the collar opening. Subsequently, in this embodiment, the shank is only then moved against the feeding direction, i.e. out of the base, and the temporary collar opening is widened to the correct dimensioning of the passage.

[0026] The dimensioning of the passage is so far simply expressed as "substantially cylindrical". However, this expression also includes variants with a targeted profiled surface of the passage wall. Thus, in one particularly advantageous embodiment, it is provided that the shank carries an external profile which is complementary to an internal spigot. This then leads to the passage through the collar produced constitutes an internal spigot into which a corresponding external spigot of a further component can be inserted in the case of a finished product. This configuration is particularly advantageous in the context of the preferred application of the application. In this preferred application, the component produced by the method according to the application is a hollow rotor shaft of an electrical machine, in particular a motor vehicle traction drive. In the engine compartment of a motor vehicle, structural space is a well-known scarce commodity. It is therefore particularly advantageous to axially accommodate a splicing point shaft for a shaft for connecting with the actual rotor shaft, which can serve to support and / or transmit the motor torque to the transmission, within the hollow actual rotor shaft. The inner wall of the passage formed by the method according to the application can be used as an engagement surface for such a splicing point. As mentioned above, in particular a spigot can be configured here.

[0027] In one particularly preferred embodiment of the device according to the application, it is provided that the pin, its shank and / or its base are replaceable. In other words, a modular forming tool is thus proposed, in which by replacing the pin or its components the size and shape of the engagement surface produced in the passage of the formed collar can be varied by simply replacing these elements. BRIEF DESCRIPTION OF DRAWINGS

[0028] Further features and advantages of the present application result from the following detailed description and the drawings.

[0029] wherein:

[0030] Fig. 1 shows a forming device according to the application in a first embodiment during the execution of the three sub-steps Figure 1a , sub-step Figure 1b and sub-step Figure 1c of the forming method shown in Fig. 1,

[0031] Fig. 2 shows a forming device according to the application in a second embodiment during the execution of the three sub-steps Figure 2a , sub-step Figure 2b and sub-step Figure 2c of the forming method shown in Fig. 1, and

[0032] Fig. 3 shows a variant of the forming device according to the application in each of the embodiments shown in Figs. 1 and 2 during the last two sub-steps of a variant of the forming method according to the application shown in sub-steps Figure 3a , sub-step Figure 3b .

[0033] The same reference signs in the figures indicate the same or similar elements. DETAILED DESCRIPTION

[0034] Fig. 1 shows three sub-steps of a forming method according to the application in its sub-steps Figure 1a , sub-step Figure 1b and sub-step Figure 1c , which are executed by means of a first embodiment of a forming device 10 according to the application working in a swing mode, in which a hollow cylindrical end section 122 of a workpiece 12 is formed into a radially inwardly turned collar 123. To this end, the workpiece 12 is clamped into a clamping device 14, which is spatially fixed in the embodiment shown. The clamping is carried out such that the cylinder axis of the hollow cylindrical end section 122, which is referred to here as workpiece axis 121, coincides with a clamping axis 141 preset by the clamping device 14. A forming tool 16 is arranged opposite the free end of the hollow cylindrical end section 122. The forming tool 16 comprises a forming face 162 which is rotationally symmetrically configured about a symmetry axis 161. In particular, in the embodiment shown, the forming face is circular and concavely curved, wherein its open side is directed towards the clamping device 14 or the workpiece 12. The symmetry axis 161 is at an azimuthal angle θ to the workpiece axis 121 or the clamping axis 141. A concentric pin 163 projects from the forming face 162. In the embodiment shown, the concentric pin comprises a substantially cylindrical shank 164, which has the contour of an external plug-in toothing 165 or a complementary external contour to an internal plug-in toothing on its outer face. Furthermore, the pin 163 comprises a base 166, which forms a continuous, smooth transition between the concave shape of the forming face 162 and the substantially cylindrical shape of the shank 164.

[0035] The forming tool 16 can be moved in several ways relative to the workpiece 12 or the clamping device 14. On the one hand, the forming tool can be moved linearly along the workpiece axis 121 or the clamping axis 141 towards the workpiece 12 or the clamping device 14 by means of a feed device 18, which is only symbolically shown as a white arrow. On the other hand, the forming tool can be placed in a swiveling movement about the workpiece axis 121 or the clamping axis 141 by means of a swiveling device 20, which is also only symbolically shown as a circular arrow.

[0036] sub Figure 1a An initial stage of the method according to the application is shown, in which the workpiece 12 and the forming tool 16 are aligned with each other as described above, and the combined feed movement and swiveling movement of the forming tool 16 is started.

[0037] sub Figure 1b A slightly later stage of the method according to the application is shown, in which the contact between the end edge of the hollow-cylindrical end section 122 of the workpiece 12 and the forming face 162 of the forming tool 16 has already taken place. Thereby, the front region of the end section 121 has already been bent radially inwards according to the concave curvature of the forming face 162, so that the construction of the turned-in collar 123 is started. Here, the actual forming process takes place locally only at the defined contact region between the workpiece 12 and the forming tool 16, respectively. Thereby, the corresponding effective pressure is increased and the occurring friction is reduced at the same force of the feed device 18 compared to a non-local forming method. It should be noted that between the stages of the forming method according to the application shown in sub Figure 1a and sub Figure 1b The azimuth angle Θ has been reduced between the stages of the forming method according to the application shown in sub

[0038] Figure 1c A final stage of the forming method according to the application is shown, in which the material of the former end section 122 flows along the forming face 162 and the pin 163, and the turned-in collar 123 is completely constructed. This collar 123 defines a passage which is (also) filled by the pin 163. After demolding, a radially and axially within the workpiece 12 and axially accessible, concentric inner spline is left. This inner spline can be used to couple a further component with the component formed from the workpiece 12.

[0039] Fig. 2 shows a sub Figure 2a , sub Figure 2b , sub Figure 2cSimilar phases of another embodiment of the forming method according to the application according to the rotation method are shown in the case of using a correspondingly modified forming device 10. In particular, the rotary apparatus is designed differently from the embodiment of Fig. 1. The rotary apparatus here consists of two sub-rotary apparatuses 20a, 20b. The first sub-rotary apparatus 20a, which is only symbolically represented in Fig. 2 as an annular arrow, rotates the forming tool 16 about its own axis of symmetry 161. The second sub-rotary apparatus 20b rotates the workpiece 12 or the clamping device 14 about the workpiece axis 121 or the clamping axis 141. The two sub-rotations are preferably performed in the same direction and are in particular so coordinated with one another in terms of their rotational speed that the relative speed in the contact region between the workpiece 12 and the forming tool 16 is minimized, preferably completely eliminated. Otherwise, reference can be made analogously to the above description with regard to Fig. 1.

[0040] In the embodiments of Figs. 1 and 2, the pin 163, in particular its shank 164, is rigidly connected with the forming face 162. In the embodiment of Fig. 3, this applies only to the base 166. Conversely, the shank 164 can be moved linearly along the axis of symmetry 161 of the forming tool 16. In the case of using such a variant of the forming device 10 according to the application, the method steps illustrated in Figs. 1 and 2 are first performed with the shank 164 retracted. This results in the situation as shown in Fig. 3. In particular, due to the absence of the stable shank 164, a shaping of the channel formed by the collar 123 can occur which deviates from the desired substantially cylindrical shape. This is shown in Fig. 3 in an exaggerated degree. The channel obtains its final shaping by means of the linear advancement of the shank travel apparatus 22, which is only symbolically represented in Fig. 3 by means of black arrows. Figure 3a Figure 3a

[0041] In yet another variant of the forming method according to the application, the shank 164 is provided to be advanced synchronously with the flow of the workpiece material, wherein the timing is preferably chosen in which the relative speed between the shank 164 and the workpiece material immediately adjacent to the shank is minimized.

[0042] Of course, the embodiments discussed in the detailed description and shown in the figures constitute only illustrative embodiments of the application. A wide variety of variations is provided to the person skilled in the art from the disclosure here. In particular, the application is not limited to a particular technical field of application. Equally, the application is preferably applied in the manufacture of rotor shafts for electric machines, in particular for electric or partially electrically powered motor vehicles.

[0043] List of reference signs

[0044] 10 forming device

[0045] 12 workpiece ​​

[0046] 121 workpiece axis

[0047] 122 end section of 12

[0048] 123 collar

[0049] 14 clamping device

[0050] 141 clamping axis

[0051] 16 forming tool

[0052] 161 symmetry axis of 16

[0053] 162 forming surface

[0054] 163 pin

[0055] 164 handle

[0056] 165 plug-in toothing

[0057] 166 base

[0058] 18 feed device

[0059] 20 rotary device

[0060] 20a sub-rotary device

[0061] 20b sub-rotary device

[0062] 22 handle travel device

[0063] θ azimuth angle

Claims

1. A device for forming a metal hollow-cylindrical end section (122) of a workpiece (12) into a radially turned-in collar (123), comprising - a clamping device (14) for clamping the workpiece (12) along a clamping axis (141) which, in the clamped state of the workpiece (12), is identical to the workpiece axis (121), i.e. to the cylinder axis of the hollow-cylindrical end section (122) of the workpiece, - a forming tool (16) which is rotationally symmetrical about a symmetry axis (161), which forming tool has a concavely curved forming face (162) facing the clamping device (14), from the centre of which forming face a coaxial pin (163) protrudes, which pin has a shank (164) and a base (166) which widens from the shank (164) towards the forming face (162) and which continuously transitions, on the one hand, into the curvature of the forming face and, on the other hand, into the shank (164), - a feed apparatus (18) by means of which the clamping device (14) and the forming tool (16) can be moved towards one another along the clamping axis (141), and - a rotation apparatus (20; 20a, b) by means of which the clamping device (14) and the forming tool (16) can be rotated relative to one another, the feed apparatus (18) and the rotation apparatus (20; 20a, b) being controllable in a combined feed process and rotation process, in which the feed apparatus (18) moves the clamping device (14) and the forming tool (16) towards one another along the clamping axis (141) and simultaneously the rotation apparatus (20; 20a, b) rotates the clamping device (14) and the forming tool (16) relative to one another, characterized in that the azimuth angle (9) between the clamping axis (141) and the symmetry axis (161) of the forming tool (16) is variable during the combined feed process and rotation process.

2. The device as claimed in claim 1, characterized in that a wobble movement of the forming tool (16) about the clamping axis (141) can be produced by means of the rotation apparatus (20).

3. The device as claimed in claim 2, characterized in that the clamping device (14) is rotationally fixed during the wobble movement.

4. The device as claimed in claim 1, characterized in that a common rotational movement of the clamping device (14) about the clamping axis (141) and of the forming tool (16) about its symmetry axis (161) can be produced by means of the rotation apparatus (20a, b).

5. The device as claimed in any of the preceding claims, characterized in that wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Further comprising a control device which is set up to operate the feeding device (18) and the rotating device (20; 20a, b) in order to monotonously reduce the azimuth angle (Θ) from a non-zero starting angle to zero during the combined feeding and rotating process.

6. The device according to any one of claims 1 to 4, characterized in that the shank (164) is movable relative to the base along the axis of symmetry (161) of the forming tool (16) by means of a shank travel device (22).

7. The device according to claim 6, characterized in that Further comprising a control device which is further set up to operate the shank travel device (22) in order to move the shank (164) towards the clamping device (14) during and / or after the combined feeding and rotating process.

8. The device according to any one of claims 1 to 4, characterized in that the shank (164) carries an outer contour which is complementary to an inner plug-in toothing.

9. The device according to any one of claims 1 to 4, characterized in that the pin (163), its shank (164) and / or its base (166) are replaceable.

10. A method for forming a metal hollow-cylindrical end section (122) of a workpiece (12) into a radially inwardly turned collar (123), comprising the following steps: - clamping the workpiece (12) along a workpiece axis (121), i.e. the cylinder axis of the hollow-cylindrical end section (122) of the workpiece (12), so that the hollow-cylindrical end section (122) faces a concavely curved forming face (162) of a forming tool (16) which is rotationally symmetrical around an axis of symmetry (161), from the center of which a coaxial pin (163) protrudes, which has a shank (164) and a base (166) which widens from the shank (164) towards the forming face (162) and continuously transitions into the curvature of the forming face on the one hand and into the shank (164) on the other hand, - performing a combined feeding and rotating process in which the workpiece (12) and the forming tool (16) are moved towards each other along the workpiece axis (121) and at the same time are rotated relative to each other, wherein during the combined feeding and rotating process, the material of the hollow-cylindrical end section (122) flows along the curved forming face (162), the base (166) and the shank (164) in succession in order to build up the collar (123), characterized in that during the combined feeding and rotating process, the azimuth angle (Θ) between the workpiece axis (121) and the axis of symmetry (161) of the forming tool (16) is varied.

11. The method according to claim 10, characterized in that during the combined feeding and rotating process, a wobbling movement of the forming tool (16) around the workpiece axis (121) is performed.

12. The method according to claim 11, characterized in that during the wobbling movement, the workpiece (12) is rotationally fixed.

13. The method according to claim 10, characterized in that during the combined feed movement and rotation movement, the workpiece (12) and the forming tool (16) are co-rotated, i.e. the workpiece (12) is rotated about its workpiece axis (121) and the forming tool (16) is rotated about its axis of symmetry (161).

14. The method according to any one of claims 10 to 13, characterized in that during the combined feed movement and rotation movement, the azimuth angle (0) is monotonously reduced from a non-zero starting angle to zero.

15. The method according to any one of claims 10 to 13, characterized in that during the combined feed movement and rotation movement and / or after the same, the shank (164) is moved towards the workpiece (12).

Images