Method and mechanical arrangement for producing a tubular hollow body from a tubular hollow body blank, in particular for producing a hollow shaft from a shaft blank

Abstract

A method and a mechanical arrangement for producing a tubular hollow body from a tubular hollow body blank, in particular for producing a hollow shaft from a shaft blank. In a method for producing a tubular hollow body from a tubular hollow body blank, a blank wall is provided, before the start of a profile-generating forming movement, with a wall projection that points, in a direction transverse to the blank wall, into the interior of the hollow body blank. During the profile-generating forming movement, the blank wall, at the wall projection, is acted upon by a profile-generating forming mandrel in a mandrel feed direction and thereby subjected to tensile stress. Following the profile-generating forming movement, a longitudinal portion of the blank wall provided with the wall projection is cut off at the hollow body blank provided with an internal profile.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] Applicant claims priority under 35 U.S.C. §119 of European Application No. 25157556.9 filed February 13, 2025, the disclosure of which is herein incorporated by reference.BACKGROUND OF THE INVENTION1. Field of the Invention

[0002] The invention relates to a method for producing a tubular hollow body from a tubular hollow body blank, in particular for producing a hollow shaft from a shaft blank, the hollow body blank having a plastically deformable blank wall and, on the blank wall, being provided with an internal profile,

[0003] in that a profile-generating forming mandrel is arranged in the interior of the hollow body blank, which profile-generating forming mandrel has a forming external profile,

[0004] in that, on the outer side of the hollow body blank, a profile-generating forming die is arranged that has a die opening designed to receive the blank wall and having a calibration section, the cross section of which is smaller than the cross section of the hollow body blank in an initial state,

[0005] in that a profile-generating forming movement is performed in which the profile-generating forming die arranged on the outer side of the hollow body blank, in a die feed direction, performs a die movement in which the profile-generating forming die is moved with the calibration section relative to the forming external profile of the profile-generating forming mandrel arranged in the interior of the hollow body blank, along the blank wall, which is at least inhibited from movement in the die feed direction,

[0006] in that, during the profile-generating forming movement, the die movement and an oppositely directed mandrel movement, which the profile-generating forming mandrel arranged in the interior of the hollow body blank performs in a mandrel feed direction opposite to the die feed direction, are superimposed on one another, the profile- generating forming mandrel, during the mandrel movement in the mandrel feed direction, exerting tensile stress on the blank wall and

[0007] in that, due to the profile-generating forming movement, material of the blank wall is plastified and the forming external profile of the profile-generating forming mandrel is reproduced on the inner side of the blank wall, thereby forming the internal profile at the blank wall of the hollow body blank.

[0008] The invention also relates to a mechanical arrangement for carrying out the above-mentioned method.2. Description of the Related Art

[0009] For example, in the production of hollow shafts for automotive engineering, shaft blanks are provided on the inner side of their wall with an internal profile in the form of a toothing. The internal toothing generated on the wall of the shaft blank is intended, on the finished hollow shaft, to interact with an external toothing of a counterpart inserted into the interior of the hollow shaft and thereby to create a positive-fit connection between the hollow shaft and the counterpart that is effective about the shaft axis. In applications where the finished hollow shaft and the counterpart are adjusted relative to one another in the longitudinal direction of the hollow shaft, the interaction of the internal toothing on the finished hollow shaft and the external toothing on the counterpart inserted into the hollow shaft guides the adjustment movements in the longitudinal direction of the hollow shaft.

[0010] Generic prior art is disclosed in EP 4 155 001 A1.

[0011] In the case of the prior art, a forming mandrel, which is provided on its outer side with a forming mandrel toothing, is arranged in the interior of a shaft blank to be shaped. A forming die having a die opening is placed on the outer side of the shaft blank. The die opening has a conical inlet and a calibration section following the conical inlet, the inner diameter of which calibration section is smaller than the outer diameter of the shaft blank to be formed in its initial state. To generate the internal toothing on the wall of the shaft blank, a die movement of the forming die seated on the outer side of the wall of the shaft blank and an oppositely directed mandrel movement of the forming mandrel arranged in the interior of the shaft blank are superimposed on one another. The shaft blank is supported in a stationary manner in the direction of the die movement. Because the inner diameter of the calibration section at the die opening is smaller than the outer diameter of the shaft blank in its initial state, beginning when the calibration section runs up onto the shaft blank, the forming die generates a force-fit connection between the wall of the shaft blank and the forming mandrel arranged in the interior of the shaft blank. This force-fit connection causes the wall of the shaft blank, during the forming process, to be subjected to tensile stress in the direction of the mandrel movement by the forming mandrel performing the mandrel movement. The tensile stress on the wall of the shaft blank by the forming mandrel performing the mandrel movement prevents the wall of the shaft blank, which is stationary in the direction of the die movement, from being compressed, on the side of the forming die located in the direction of the die movement, due to the die movement. As a result of the shaping process, an internal toothing is produced on the wall of the shaft blank as an internal profile, into which internal toothing a corresponding external toothing on a counterpart to be coupled to the hollow shaft can be inserted in the longitudinal direction.SUMMARY OF THE INVENTION

[0012] The object of the present invention is to provide an alternative to the previously known production method and the previously known mechanical arrangement.

[0013] According to the invention, this object is achieved by a method and a mechanical arrangement as described below.

[0014] In the case of the invention, during the profile-generating forming movement, there is, in addition to a force-fit, also a positive-fit between the profile-generating forming mandrel performing a mandrel movement and the blank wall to be formed. Accordingly, during the shaping process, the blank wall is subjected, to a particularly high degree, to tensile stress in the mandrel feed direction, and compressing of the blank wall on the side of the profile-generating forming die, moved in the opposite direction to the profile-generating forming mandrel, that faces in the direction of the die movement is particularly effectively prevented. The calibration section of the profile-generating forming die is preferably smooth-walled.

[0015] To prepare the positive fit between the profile-generating forming mandrel and the blank wall, the blank wall, before the start of the profile-generating forming movement, is provided, by means of a projection-generating forming device, with a wall projection that points into the interior of the hollow body blank. During the shaping process, the wall projection functions as a support for the profile-generating forming mandrel moved in the mandrel feed direction.

[0016] Upon completion of the forming process, a longitudinal portion of the blank wall provided with the wall projection is, by means of a separating device of the mechanical arrangement according to the invention, cut off in order to make the internal profile generated on the blank wall accessible for an external profile of a counterpart to be inserted into the finished hollow body.

[0017] Particular embodiments of the method and mechanical arrangement can be found in the description below and in the dependent claims.

[0018] In one embodiment of the method and mechanical arrangement according to the invention, a hollow body blank is provided with an internal profile in the form of an internal toothing. For this purpose, a toothing-generating forming mandrel is provided as the profile-generating forming mandrel, and a toothing-generating forming die is provided as the profile-generating forming die. A toothing-generating forming movement of the toothing-generating forming mandrel and the toothing-generating forming die is carried out by means of a toothing-generating forming drive of the mechanical arrangement according to the invention.

[0019] To allow the external toothing on the counterpart to be easily inserted into the internal toothing on the finished hollow body, the longitudinal portion of the blank wall provided with the wall projection is cut off along a separating line that, on the side of the internal toothing of the blank wall located in the mandrel feed direction, extends outside the internal toothing. As a result of the described arrangement of the separating line relative to the internal toothing of the blank wall, in particular the formation of a burr on the internal toothing, otherwise associated with the separation process, is avoided. A burr on the internal toothing of the blank wall would at least hinder the insertion of the external toothing of the counterpart into the internal toothing on the finished hollow body, as well as adjustment movements that the finished hollow body and the counterpart inserted into the finished hollow body perform relative to one another in the longitudinal direction, and would therefore have to be removed in a separate operation.

[0020] Further preferred embodiments according to the invention related to mechanically producing the wall projection of the blank wall that, during the profile- or toothing forming movement, is used as a support for the profile- or toothing-generating mandrel.

[0021] By means of a projection-generating forming mandrel arranged in the interior of the hollow body blank and a projection-generating forming die seated on the outer side of the blank wall, a partial length of the blank wall projecting in the longitudinal direction relative to the projection-generating forming mandrel is formed into the wall projection projecting into the interior of the hollow body blank. Preferably, for this purpose, the projection-generating forming die performs a projection-generating forming movement along the projecting portion of the blank wall directed toward the projection-generating forming mandrel, during which movement the projection-generating forming mandrel does not change its position.

[0022] In a further development of the invention, the profile-generating or toothing-generating forming die is provided as the projection-generating forming die (claim 10).

[0023] In principle, according to the invention, it is possible to use the profile-generating or toothing-generating forming mandrel to create the wall projection of the blank wall that points into the interior of the hollow body blank.

[0024] In generating an internal toothing on the blank wall, the use of different forming mandrels, one for the projection-generating shaping of the blank wall and one for the toothing-generating shaping of the blank wall, is preferred.

[0025] By means of an in particular smooth-walled portion, preferably an in particular smooth-walled end portion, of the projection-generating forming mandrel, the separation process, which follows the generation of the internal toothing of the hollow body blank, is prepared during the generation of the wall projection projecting into the interior of the hollow body blank. By means of the in particular smooth-walled portion of the projection-generating forming mandrel and the projection-generating forming die cooperating therewith, an in particular smooth-walled inner wall portion is generated on the inner side of the blank wall, on which inner wall portion, when the wall projection of the internally toothed blank wall is cut off, the separating line extends, along which the longitudinal portion of the blank wall provided with the wall projection is cut off. Because the cross section of the in particular smooth-walled portion of the projection-generating forming mandrel is at least as large as the cross section of the toothing-generating forming mandrel delimited by the tip line of the shaping toothing, the inner wall portion of the blank wall created by means of the smooth-walled portion of the projection-generating forming mandrel has a cross section that is as large as or larger than the cross section delimited by the root line of the internal toothing of the blank wall generated by means of the toothing-generating forming mandrel. As a result, the internal toothing on the finished hollow body is freely accessible in the longitudinal direction for the external toothing of the counterpart when the counterpart is inserted into the finished hollow body.

[0026] The portion of the projection-generating forming mandrel that generates the aforementioned inner wall portion of the blank wall does not necessarily have to be smooth-walled. Rather, the portion of the projection-generating forming mandrel in question can, for example, also have a toothing. In this case, the cross section delimited by the root line of the toothing on the relevant portion of the projection-generating forming mandrel is preferably at least as large as the cross section delimited by the tip line of the toothing on the toothing-generating forming mandrel.

[0027] The toothing-generating forming die or a projection-generating forming die identical in construction to the toothing-generating forming die with respect to the cross section of the calibration section provided at the die opening is used as the projection-generating forming die. The cross section of the calibration section on the projection- generating forming die is, taking into account the thickness of the hollow body wall, matched to the cross section of the portion of the projection-generating forming mandrel that generates the inner wall portion of the blank wall. Correspondingly, the cross section of the calibration section at the toothing-generating forming die and the cross section of the toothing-generating forming mandrel in the region of the shaping toothing are matched to one another.

[0028] According a further development of the invention, the generation of the internal toothing on the blank wall is followed by additional processing of the hollow body blank, which additional processing is carried out before or after the longitudinal portion of the blank wall provided with the wall projection is cut off. Additional processing includes, in particular, further forming of the hollow body wall.

[0029] A preferred application for the invention is the manufacture of tubular hollow bodies having a circular cross section. The mechanical arrangement used to generate an internal toothing on the blank wall comprises a toothing-generating forming mandrel having a forming toothing, the tip line of which is designed as a tip circle and the root line of which is designed as a root circle. The projection-generating forming mandrel and the calibration section of the toothing-generating forming die, and consequently also the calibration section of the projection-generating forming die, likewise have a circular cross section.BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Other objects and features of the invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention.

[0031] In the drawings,

[0032] FIG. 1 shows a shaft blank in an initial state;

[0033] FIG. 2 shows the mechanical arrangement according to the invention in a first part of the method;

[0034] FIG. 3 shows the shaft blank after removal of the projection-generating forming mandrel and the projection-generating forming die;

[0035] FIG. 4 shows the conditions at the end of the toothing-generating forming movement;

[0036] FIG. 5 shows the internally toothed shaft blank of FIG. 4 after removal of the toothing-generating forming mandrel and the toothing-generating forming die;

[0037] FIG. 6 shows the shaft blank of FIG. 5 after a longitudinal portion of the tube wall provided with a wall projection has been cut off; and

[0038] FIG. 7 shows the finished hollow shaft.DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0039] FIG. 1 shows the shaft blank 2 in an initial state. The shaft blank 2 has, as the blank wall, a tube wall 4 that is circular in cross section and open on both sides. In the example shown, the tube wall 4 is made of alloyed steel and is plastically deformable.

[0040] In a first method step, the shaft blank 2 is provided with a wall projection 5 that points, in a direction transverse to the tube wall 4, into the interior of the shaft blank 2 (FIG. 2).

[0041] For this purpose, the mechanical arrangement 3 has a projection-generating forming device 6, which in turn comprises a projection-generating forming mandrel 7, a projection-generating forming die 8 and a projection-generating forming drive 9.

[0042] The projection-generating forming die 8 has a die opening 10 having a conical inlet 11 and a calibration section 12 following the conical inlet 11. The calibration section 12 of the die opening 10 has smooth walls and a circular cross section. The inner diameter of the calibration section 12 is smaller than the outer diameter of the shaft blank 2 in the initial state.

[0043] The projection-generating forming mandrel 7 likewise has a circular cross section and is likewise smooth-walled.

[0044] At the beginning (not shown) the projection-generating forming mandrel 7 was positioned in the interior of the shaft blank 2 such that the tube wall 4 has a projecting portion in the longitudinal direction with respect to the projection-generating forming mandrel 7. The projection-generating forming die 8 was arranged on the outer side of the shaft blank 2.

[0045] Then, the projection-generating forming die 8 arranged on the outer side of the shaft blank 2 was moved in the direction of an arrow 13 by means of the projection-generating forming drive 9. In this process, the projection-generating forming die 8 initially moved with the calibration section 12 along the portion of the tube wall 4 projecting relative to the projection-generating forming mandrel 7. In this process, the projection-generating forming die 8 deformed the projecting portion of the tube wall 4, thereby forming the inwardly pointing wall projection 5 of the tube wall 4.

[0046] After passing the projecting portion of the tube wall 4, the projection-generating forming die 8 moved, relative to the projection-generating forming mandrel 7 arranged in the interior of the shaft blank 2, along a longitudinal portion of the tube wall 4 that adjoins the projecting portion of the tube wall 4 and that extends at the level of the projection-generating forming mandrel 7 arranged in the interior of the shaft blank 2. As a result of this movement of the projection-generating forming die 8, the smooth-walled end portion of the projection-generating forming mandrel 7 traversed by the projection-generating forming die 8 was reproduced on the inner side of the tube wall 4, thereby generating a smooth-walled inner wall portion 14 of the tube wall 4. Because the annular gap between the calibration section 12 of the projection-generating forming die 8 and the projection-generating forming mandrel 7 is smaller than the thickness of the tube wall 4 in the initial state, the portion of the tube wall 4 provided with the smooth-walled inner wall portion 14 is thinner compared to the rest of the tube wall 4.

[0047] The resulting conditions are shown in FIGS. 2 and 3.

[0048] Both during the forming of the projecting portion of the tube wall 4 with into the wall projection 5 and during the movement of the projection-generating forming die 8 over the smooth-walled end portion of the projection-generating forming mandrel 7, the forming mandrel 7 is fixedly arranged in the interior of the shaft blank 2 and the shaft blank 2 is fixed in the direction 13 of the die movement by means of an axial support 15 of the mechanical arrangement 3.

[0049] FIG. 3 shows the shaft blank 2 according to FIG. 2 after removal of the projection-generating forming mandrel 7 and the projection-generating forming die 8.

[0050] An internal profile in the form of internal toothing is now generated on the tube wall 4 of the shaft blank 2 provided with the wall projection 5 and the smooth-walled inner wall portion 14.

[0051] For this purpose, a toothing-generating forming device 16 is provided as the profile-generating forming device.

[0052] To generate the internal toothing on the tube wall 4, the shaft blank 2 shown in FIG. 3 is again arranged with its end on the left in the drawing on the axial support 15 of the mechanical arrangement 3. Subsequently, as the profile-generating forming mandrel, a toothing-generating forming mandrel 17 of the toothing-generating forming device 16 is arranged in the interior of the shaft blank 2, and, as the profile-generating forming die, a toothing-generating forming die 18 of the toothing-generating forming device 16 is arranged on the outer side of the shaft blank 2.

[0053] The toothing-generating forming mandrel 17 is inserted into the interior of the shaft blank 2 until its leading end comes to bear against the side of the wall projection 5 of the tube wall 4 that faces toward the interior of the shaft blank 2. A forming external toothing 19 of the toothing-generating forming mandrel 17, provided as the forming external profile, now extends on the inner side of the shaft blank 2 along the partial length of the tube wall 4 to be provided with the internal toothing.

[0054] In the example shown, the toothing-generating forming die 18 is the projection-generating forming die 8. Alternatively, a forming die could be used as the toothing-generating forming die 18, which forming die corresponds to the projection-generating forming die 8 with respect to the geometry of the conical entry 11 and the calibration section 12.

[0055] The toothing-generating forming die 18 moves from the right onto the end of the tube wall 4 on the right in FIG. 3 until the conical inlet 11 of the toothing-generating forming die 18 receives a shoulder 20 formed on the tube wall 4 and the calibration section 12 of the toothing-generating forming die 18 comes to bear against the outer side of the smooth-walled inner portion 14 of the tube wall 4.

[0056] Based on the resulting conditions, a profile-generating or toothing-generating forming movement is carried out by means of a profile-generating or toothing-generating forming drive 21 of the toothing-generating forming device 16.

[0057] In this process, the toothing-generating forming die 18 arranged on the outer side of the shaft blank 2 is moved, by means of a toothing-generating die drive 22 of the toothing-generating forming drive 21 provided as a profile-generating forming die drive, with a die movement in a die feed direction 23, in which die movement the toothing-generating forming die 18 moves with the calibration section 12, while drawing out the tube wall 4, relative to the forming external toothing 19 of the toothing-generating forming mandrel 7 arranged in the interior of the shaft blank 2, along the tube wall 4 that is stationary in the die feed direction 23.

[0058] By means of a drive control 24 of the toothing-generating forming drive 21, a mandrel movement of the toothing-generating forming mandrel 17 arranged in the interior of the shaft blank 2 is superimposed on the die movement carried out in the die feed direction 23. The mandrel movement is generated by a toothing-generating mandrel drive 25 of the toothing-generating forming drive 21 provided as the profile-generating mandrel drive and is carried out in a mandrel feed direction 26 opposite to the die feed direction 23.

[0059] During the mandrel movement, the toothing-generating forming mandrel 17 acts in a positive manner on the wall projection 5 of the tube wall 4 in the mandrel feed direction 26. This results in a tensile stress on the tube wall 4 in the mandrel feed direction 26. This tensile stress on the tube wall 4 prevents the tube wall 4 from being compressed, on the side of the toothing-generating forming die 18 that faces the axial support 15, by the toothing-generating forming die 18 moving in the die feed direction 23.

[0060] As a result of the toothing-generating forming movement, material of the tube wall 4 is plastified and the forming external toothing 19 of the toothing-generating forming mandrel 17 is reproduced on the inner side of the tube wall 4, thereby forming an internal toothing 27 at the tube wall 4 of the shaft blank 2 (FIG. 5).

[0061] FIG. 4 shows the conditions at the end of the toothing-generating forming movement. The toothing-generating forming die 18 has reached its final position on the outer side of the now internally toothed shaft blank 2. The toothing-generating forming mandrel 17 is located, in its final position, in the interior of the shaft blank 2. The end of the toothing-generating forming mandrel 17 on the right in FIG. 4 still bears against the inner side of the wall projection 5.

[0062] In the further course of the method, the toothing-generating forming die 18 is removed from the outer side of the shaft blank 2 and the toothing-generating forming mandrel 17 is removed from the interior of the shaft blank 2. The shaft blank 2 is then removed from the axial support 15.

[0063] In the next method step, a longitudinal portion 29 of the tube wall 4 provided with the wall projection 5 is cut off from the shaft blank 2 provided with the internal toothing 27 by means of a separating device 28 of the mechanical arrangement 3 (FIG. 5). In the example shown, the separation process is carried out by cutting. The separating line of the separation process extends along the smooth-walled inner wall portion 14 of the tube wall 4.

[0064] In the example shown, the tip circle diameter of the forming external toothing of the toothing-generating forming mandrel 17 is identical to the outer diameter of the smooth-walled projection-generating forming mandrel 7. As a result, the root circle diameter of the internal toothing 27 generated on the inner side of the tube wall 4 corresponds to the diameter of the smooth-walled inner wall portion 14 of the tube wall 4 adjacent to the internal toothing and generated by means of the projection-generating forming mandrel 7. The smooth-walled inner wall portion 14 of the tube wall 4 is therefore aligned with the root circle of the internal toothing 27.

[0065] After the longitudinal portion 29 has been cut off, the shaft blank 2 is as shown in FIG. 6.

[0066] Finally, the shaft blank 2 is formed in a portion adjacent to the internal toothing 27 by means of a conventional forming device, in the example shown by means of a rotary swaging device 30. This results in the finished hollow shaft 1 as shown in FIG. 7.

[0067] An externally toothed counterpart (not shown), which is to be coupled to the internal toothing 27 of the hollow shaft 1 at an external toothing, can be readily inserted into the hollow shaft 1 from the side of the hollow shaft 1 on the right in FIG. 7. Accordingly, the hollow shaft 1 and the counterpart accommodated in the interior of the hollow shaft 1 can be readily adjusted relative to each other in the longitudinal direction, if required. In the case of any adjustment movements, the hollow shaft 1 and the counterpart are guided by the mutually meshing toothing on both sides.

[0068] Although only a few embodiments of the present invention have been shown and described, it is to be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.

Claims

1. A method for producing a tubular hollow body from a tubular hollow body blank, the hollow body blank having a plastically deformable blank wall and, on the blank wall, being provided with an internal profile, the method comprising:arranging a profile-generating forming mandrel in an interior of the hollow body blank, the profile-generating forming mandrel having a forming external profile,arranging, on an outer side of the hollow body blank, a profile-generating forming die that has a die opening designed to receive the blank wall and having a calibration section, a cross section of which is smaller than a cross section of the hollow body blank in an initial state, andperforming a profile-generating forming movement in which the profile-generating forming die arranged on the outer side of the hollow body blank, in a die feed direction, performs a die movement in which the profile-generating forming die is moved with the calibration section relative to the forming external profile of the profile-generating forming mandrel arranged in the interior of the hollow body blank, along the blank wall, which is at least inhibited from movement in the die feed direction,wherein, during the profile-generating forming movement, the die movement and an oppositely directed mandrel movement, which the profile-generating forming mandrel arranged in the interior of the hollow body blank performs in a mandrel feed direction opposite to the die feed direction, are superimposed on one another, the profile-generating forming mandrel, during the mandrel movement in the mandrel feed direction, exerting tensile stress on the blank wall,wherein, due to the profile-generating forming movement, material of the blank wall is plastified and the forming external profile of the profile-generating forming mandrel is reproduced on the inner side of the blank wall, thereby forming the internal profile at the blank wall of the hollow body blank,wherein before starting the profile-generating forming movement, the blank wall is provided with a wall projection that points, in a direction transverse to the blank wall, into the interior of the hollow body blank, which wall projection, during the profile-generating forming movement, is arranged on a side, located in the mandrel feed direction, of the profile-generating forming mandrel arranged in the interior of the hollow body blank and, in a direction transverse to the blank wall, engages over the profile-generating forming mandrel arranged in the interior of the hollow body blank,wherein the blank wall, during the profile-generating forming movement, is subjected to tensile stress by the profile-generating forming mandrel in the mandrel feed direction by the profile-generating forming mandrel acting in a positive manner on the wall projection of the blank wall in the mandrel feed direction, andwherein, following the profile-generating forming movement, a longitudinal portion of the blank wall provided with the wall projection is cut off at the hollow body blank provided with the internal profile.

2. The method according to claim 1, wherein the blank wall is provided with the inwardly pointing wall projection in the following method steps:arranging, in the interior of the hollow body blank, a projection-generating forming mandrel such that the blank wall has a projecting portion in the longitudinal direction with respect to the projection-generating forming mandrel,arranging, on the outer side of the hollow body blank, a projection-generating forming die that has a die opening designed to receive the blank wall and having a calibration section, the cross section of the die opening of the projection-generating forming die at the calibration section being smaller than the cross section of the hollow body blank in the initial state,moving the projection-generating forming die arranged on the outer side of the hollow body blank so as to perform a projection-generating forming movement in which the projection-generating forming die is moved with the calibration section along the projecting portion of the blank wall,wherein, due to the projection-generating forming movement of the projection-generating forming die, the projecting portion of the blank wall is deformed, thereby forming the inwardly pointing wall projection of the blank wall.

3. The method according to claim 1, wherein the internal profile is in the form of an internal toothing,wherein, in the interior of the hollow body blank a toothing-generating forming mandrel is arranged as the profile-generating forming mandrel that has as the forming external profile, a forming external toothing,wherein, on the outer side of the hollow body blank, a toothing-generating forming die is arranged as the profile-generating forming die,wherein, as the profile-generating forming movement, a toothing-generating forming movement is performed in which the toothing-generating forming die arranged on the outer side of the hollow body blank, in the die feed direction, performs a die movement in which the toothing-generating forming die is moved with the calibration section relative to the forming external toothing of the toothing-generating forming mandrel arranged in the interior of the hollow body blank, along the blank wall, which is at least inhibited from movement in the die feed direction,wherein, during the toothing-generating forming movement, the die movement and the oppositely directed mandrel movement, which the toothing-generating forming mandrel arranged in the interior of the hollow body blank performs in the mandrel feed direction, are superimposed on one another, andwherein, due to the toothing-generating forming movement, material of the blank wall is plastified and the forming external toothing of the toothing-generating forming mandrel is reproduced on the inner side of the blank wall, thereby forming the internal toothing at the blank wall of the hollow body blank,wherein the blank wall is provided, before starting the toothing-generating forming movement, with the wall projection that points, in a direction transverse to the blank wall, into the interior of the hollow body blank, which wall projection, during the toothing-generating forming movement, is arranged on the side, located in the mandrel feed direction, of the toothing-generating forming mandrel arranged in the interior of the hollow body blank and, in a direction transverse to the blank wall, engages over the toothing-generating forming mandrel arranged in the interior of the hollow body blank,wherein the blank wall, during the toothing-generating forming movement, is subjected to tensile stress by the toothing-generating forming mandrel in the mandrel feed direction by the toothing-generating forming mandrel acting in a positive manner on the wall projection of the blank wall in the mandrel feed direction, andwherein, following the toothing-generating forming movement on the hollow body blank provided with the internal toothing, the longitudinal portion of the blank wall provided with the wall projection is cut off along a separating line that, on the side of the internal toothing of the hollow body blank located in the mandrel feed direction, extends outside the internal toothing of the hollow body blank.

4. The method according to claim 3,wherein the projection-generating forming mandrel is arranged in the interior of the hollow body blank such that a smooth-walled portion of the projection-generating forming mandrel faces toward the projecting portion of the blank wall, the smooth-walled portion of the projection-generating forming mandrel having a cross section that is at least as large as the cross section of the toothing-generating forming mandrel in the region of the forming external toothing,wherein, as the projection-generating forming die, the toothing-generating forming die or a projection-generating forming die identical in construction to the toothing-generating forming die with respect to the cross section of the die opening at the calibration section is moved, with the projection-generating forming movement along the projecting portion of the blank wall and also relative to the projection-generating forming mandrel arranged in the interior of the hollow body blank, along a longitudinal portion of the blank wall that adjoins the projecting portion of the blank wall and that extends at the level of the portion of the projection-generating forming mandrel arranged in the interior of the hollow body blank, the smooth-walled portion of the projection-generating forming mandrel, due to the movement of the projection-generating forming die over the smooth-walled portion of the projection-generating forming mandrel, being reproduced on the inner side of the blank wall, thereby generating an smooth-walled inner wall portion of the blank wall,wherein, after the generation of the inner smooth-walled inner portion of the blank wall, the toothing-generating forming mandrel, instead of the projection-generating forming mandrel, is arranged in the interior of the hollow body blank, and the toothing-generating forming movement is carried out, andwherein a separating line, along which the longitudinal portion of the blank wall provided with the wall projection is cut off, extends at the smooth-walled inner wall portion of the blank wall.

5. The method according to claim 1, wherein the hollow body blank provided with the internal profile is additionally processed before or after cutting off the longitudinal portion of the blank wall provided with the wall projection.

6. The method according to claim 1, wherein the hollow body blank has a circular cross section and is provided with the internal profile by means of a round profile-generating forming mandrel and by means of a forming die having a round cross section of the calibration section.

7. A mechanical arrangement for producing a tubular hollow body from a tubular hollow body blank that has a plastically deformable blank wall, comprising:a profile-generating forming device that comprises a profile-generating forming mandrel, a profile-generating forming die and a profile-generating forming drive,the profile-generating forming mandrel having a forming external profile,the profile-generating forming die having a die opening designed to receive the blank wall and having a calibration section, a cross section of which is smaller than a cross section of the hollow body blank in an initial state,the profile-generating forming drive having a profile-generating mandrel drive, a profile-generating die drive and a drive control,the profile-generating forming mandrel with the forming external profile being configured to be arranged in an interior of the hollow body blank,the profile-generating forming die being configured to be arranged on the outer side of the hollow body blank,the profile-generating forming drive being configured to carry out a profile-generating forming movement,the profile-generating die drive being configured to move the profile-generating forming die arranged on the outer side of the hollow body blank during the profile-generating forming movement, with a die movement in a die feed direction, in which die movement the profile-generating forming die moves with the calibration section relative to the forming external profile of the profile-generating forming mandrel arranged in the interior of the hollow body blank, along the blank wall, which is at least inhibited from movement in the die feed direction,wherein the drive control of the profile generating forming drive is configured, during the profile-generating forming movement, to superimpose the die movement and an oppositely directed mandrel movement generated by the profile-generating mandrel drive, which the profile-generating forming mandrel arranged in the interior of the hollow body blank performs in a mandrel feed direction opposite to the die feed direction, on one another, the profile-generating forming mandrel, during the mandrel movement, exerting tensile stress on the blank wall in the mandrel feed direction andwherein due to the profile-generating forming movement, material of the blank wall is plastified and the forming external profile of the profile-generating forming mandrel is reproduced on the inner side of the blank wall, thereby forming an internal profile at the blank wall of the hollow body blank,wherein the mechanical arrangement further comprises a projection-generating forming device, which is configured to form the blank wall before the start of the profile-generating forming movement, thereby forming a wall projection that points, in a direction transverse to the blank wall, into the interior of the hollow body blank, which wall projection, during the profile-generating forming movement, is arranged on a side, located in the mandrel feed direction, of the profile-generating forming mandrel arranged in the interior of the hollow body and, in a direction transverse to the blank wall, is configured to engage over the profile-generating forming mandrel arranged in the interior of the hollow body blank, the blank wall, during the profile-generating forming movement, being subjected to tensile stress by the profile-generating forming mandrel in the mandrel feed direction, wherein the profile-generating forming mandrel is configured to act in a positive manner on the wall projection of the blank wall in the mandrel feed direction andfurther comprising a separating device that is configured to cut off a longitudinal portion of the blank wall provided with the wall projection at the hollow body blank provided with the internal profile following the profile-generating forming movement.

8. The mechanical arrangement according to claim 7, wherein:as the profile-generating forming device, a toothing-generating forming device is provided that has a toothing-generating forming mandrel as the profile-generating forming mandrel, a toothing-generating forming die as the profile-generating forming die, and a toothing-generating forming drive as the profile-generating forming drive,the toothing-generating forming mandrel has a forming external toothing as the forming external profile,the toothing-generating forming drive has a toothing-generating mandrel drive as the profile-generating mandrel drive and a toothing-generating die drive as the profile-generating die drive,the toothing-generating forming mandrel with the forming external toothing is configured to be arranged in the interior of the hollow body blank,the toothing-generating forming die is configured to be arranged on the outer side of the hollow body blank,the toothing generating forming drive is configured to carry out a toothing-generating forming movement as the profile-generating forming movement,the profile-generating die drive is configured, during the toothing-generating forming movement, to move the toothing-generating forming die arranged on the outer side of the hollow body blank, with a die movement in the die feed direction , in which die movement the toothing-generating forming die moves with the calibration section relative to the forming external toothing of the toothing-generating forming mandrel arranged in the interior of the hollow body blank, along the blank wall, which is at least inhibited from movement in the die feed direction,the drive control of the toothing generating forming drive is configured, during the toothing-generating forming movement, to superimpose the die movement and an oppositely directed mandrel movement generated by the toothing-generating mandrel drive, which the toothing-generating forming mandrel arranged in the interior of the hollow body blank performs in a mandrel feed direction opposite to the die feed direction, on one another,due to the toothing-generating forming movement, material of the blank wall is plastified and the forming external toothing of the toothing-generating forming mandrel is reproduced on the inner side of the blank wall, thereby forming an internal toothing provided as the internal profile at the blank wall of the hollow body blank,wherein, the projection generating forming device is configured to form the blank wall, before the start of the toothing-generating forming movement, thereby forming the wall projection that points, in a direction transverse to the blank wall, into the interior of the hollow body blank, which wall projection, during the toothing-generating forming movement, is arranged on the side, located in the mandrel feed direction, of the toothing-generating forming mandrel arranged in the interior of the hollow body blank and, in a direction transverse to the blank wall, engages over the toothing-generating forming mandrel arranged in the interior of the hollow body blank, the blank wall, during the toothing-generating forming movement, being subjected to tensile stress by the toothing-generating forming mandrel in the mandrel feed direction , wherein the toothing-generating forming mandrel is configured to act in a positive manner on the wall projection of the blank wall in the mandrel feed direction andwherein the separating device is configured to cut off the longitudinal portion of the blank wall provided with the wall projection along a separating line that, on the side of the internal toothing of the hollow body blank located in the mandrel feed direction, extends outside the internal toothing of the hollow body blank.

9. The mechanical arrangement according to claim 7, wherein the projection-generating forming device comprises a projection-generating forming mandrel, a projection-generating forming die and a projection-generating forming drive,the projection-generating forming mandrel being configured to be arranged in the interior of the hollow body blank such that the blank wall has a projection in the longitudinal direction with respect to the projection-generating forming mandrel,the projection-generating forming die being configured to be arranged on the outer side of the hollow body blank, and said projection-generating forming die having a die opening designed to receive the blank wall and having a calibration section, the cross section of which is smaller than the cross section of the hollow body blank in the initial state,the projection-generating forming drive being configured to move the projection-generating forming die arranged on the outer side of the hollow body blank with a projection-generating forming movement in which the projection-generating forming die moves with the calibration section along the projecting portion of the blank wall, andsuch that due to the projection-generating forming movement of the projection-generating forming die, the projecting portion of the blank wall is deformed, thereby forming the inwardly pointing wall projection of the blank wall.

10. The mechanical arrangement according to claim 9, wherein the profile-generating forming die is provided as the projection-generating forming die.

11. The mechanical arrangement according to claim 9, wherein the profile-generating forming mandrel is provided as the projection-generating forming mandrel.

12. The mechanical arrangement according to claim 8,wherein the projection-generating forming mandrel has a smooth-walled portion having a cross section that is at least as large as the cross section of the toothing-generating forming mandrel in the region of the forming external toothing,wherein the projection-generating forming mandrel is configured to be arranged in the interior of the hollow body blank such that the projection-generating forming mandrel with the smooth-walled portion faces toward the projecting portion of the blank wall,wherein the toothing-generating forming die, or a projection-generating forming die identical in construction to the toothing-generating forming die with respect to the cross section of the die opening at the calibration section, is provided as the projection-generating forming die,wherein the projection-generating forming drive is configured to move the projection-generating forming die with the projection-generating forming movement along the projecting portion of the blank wall and also relative to the projection-generating forming mandrel arranged in the interior of the hollow blank, along a longitudinal portion of the blank wall that adjoins the projecting portion of the blank wall and that extends at the level of the smooth-walled portion of the projection-generating forming mandrel arranged in the interior of the hollow blank, the smooth-walled portion of the projection-generating forming mandrel, due to the movement of the projection-generating forming die over the smooth-walled portion of the projection-generating forming mandrel, being reproduced on the inner side of the blank wall, thereby generating an smooth-walled inner wall portion of the blank wall,wherein, after the generation of the smooth-walled inner wall portion of the blank wall, the toothing-generating forming mandrel, instead of the projection-generating forming mandrel, is configured to be arranged in the interior of the hollow body blank, for carrying out the toothing-generating forming movement, andwherein the separating line, along which the longitudinal portion of the blank wall provided with the wall projection can be cut off, extends along the smooth-walled inner wall portion of the blank wall.

13. The mechanical arrangement according to claim 7, further comprising a processing device configured to process the hollow body blank provided with the internal profile following the profile-generating forming movement.

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