Method and machine arrangement for producing a wall profile on a plastically deformable hollow body wall

Abstract

To create a wall profile on an inner side of a plastically deformable hollow body wall (2) of a hollow body (1), a forming mandrel (8) is arranged inside a cavity (3) of the hollow body (1) such that the forming mandrel (8) extends at the level of a first longitudinal section (l1) of the hollow body wall (2) with a cross-sectionally expanded mandrel section (12) which has a shaping mandrel profile section as well as a cross-sectional excess compared to a cross-sectionally reduced mandrel section (14) which extends at the level of a second longitudinal section (l2) of the hollow body wall (2) following the first longitudinal section (l1) of the hollow body wall (2) and has a further shaping mandrel profile section. A forming die (9) is moved with a forming motion relative to the hollow body wall (2) and relative to the cross-section enlarged mandrel section (12) and relative to the cross-section reduced mandrel section (14) of the forming mandrel (8).A mechanical arrangement is designed to carry out the above procedure.

Description

[0001] The invention relates to a method for producing a wall profile on an inner side of a plastically deformable hollow body wall of a hollow body, wherein the hollow body wall defines a cavity of the hollow body which is open on at least one side forming a cavity opening, and wherein the hollow body wall is reshaped. by arranging a forming mandrel, which has a forming mandrel profile, in the interior of the cavity of the hollow body such that the forming mandrel with the forming mandrel profile extends along the hollow body wall, and by arranging a forming die with a die opening on the outside of the hollow body and moving it with a forming motion along the hollow body wall passing through the die opening relative to the hollow body wall and relative to the forming mandrel, whereby the wall profile on the inside of the hollow body wall is produced by plasticizing material of the hollow body wall due to the forming motion of the forming die and by mapping the forming mandrel profile on the inside of the hollow body wall as the wall profile.

[0002] The invention also relates to a mechanical arrangement for carrying out the aforementioned method.

[0003] For example, in the production of hollow shafts for automotive manufacturing, shaft blanks must be provided with a wall profile, in particular with internal teeth, on the inside of their wall. The internal profile produced on the wall of the shaft blank is designed to interact with an external profile of a counterpart inserted into the interior of the hollow shaft, thereby creating a positive-locking connection around the shaft axis between the hollow shaft and the counterpart.

[0004] EP 4 155 001 A1 discloses a generic method and a generic machine arrangement for such applications, among others.

[0005] In the prior art, a forming mandrel, which is provided on its outer surface with a forming mandrel toothing and has a uniform cross-section over its entire length, is positioned inside a shaft blank to be formed. A forming die with a die opening is placed on the shaft blank and moved along the shaft blank through the die opening, relative to the forming mandrel located inside the shaft blank, in a forming motion. Due to the forming motion of the forming die, the wall of the shaft blank is deformed by plasticized material from the wall of the shaft blank entering the spaces between the teeth of the forming mandrel toothing and thereby forming a tooth profile on the inner surface of the shaft blank wall.

[0006] The object of the present invention is to provide for the event that, after the forming of the hollow body wall, the cross-section of the cavity bounded by the formed hollow body wall narrows over a portion of the hollow body wall, thereby making it difficult to insert a counterpart intended to be received by the formed hollow body into the cavity of the formed hollow body. Such a cross-sectional narrowing of the cavity of the formed hollow body can result from a material-related elastic recovery of the hollow body wall that is uneven along its length and occurs automatically when the forming mandrel is removed from the interior of the hollow body after the forming process is complete.Another conceivable cause for a cross-sectional narrowing of the aforementioned type is, for example, the subsequent attachment of an additional component to the outside of the finished formed hollow body wall, if the additional component surrounds the hollow body wall in a ring-like manner in its circumferential direction and is prestressed in its circumferential direction for fixation on the hollow body wall.

[0007] The above problem is solved according to the invention by the method according to claim 1 and by the mechanical arrangement according to claim 8.

[0008] In the invention, a stepped forming mandrel is used, comprising a mandrel section with an expanded cross-section and a mandrel section with a reduced cross-section. Each mandrel section has a forming mandrel profile section. The forming mandrel profiles of the two mandrel sections preferably have an identical basic geometry, with the forming mandrel profile of the expanded mandrel section being scaled outwards in the transverse direction of the hollow body wall, i.e., towards the hollow body wall, compared to the forming mandrel profile of the reduced mandrel section. The transition between the forming mandrel profile of the expanded mandrel section and the forming mandrel profile of the reduced mandrel section can be stepped or continuous.

[0009] To form the hollow body wall, which is to be provided with a wall profile on its inner surface, the forming mandrel is positioned inside the hollow body such that the mandrel section with its forming profile is located at the level of a first longitudinal section of the hollow body wall. The mandrel section with its forming profile is positioned at the level of a second longitudinal section of the hollow body wall, following the first longitudinal section. The longitudinal section of the hollow body wall associated with the mandrel section can be located at one end of the hollow body or at a distance from the ends.

[0010] During its forming motion, the forming die is moved along the hollow body wall relative to the cross-sectionally expanded and the cross-sectionally reduced mandrel sections by means of the forming drive. A die drive is preferably provided as the forming drive.

[0011] The hollow body wall is at least restrained against movement in the direction of the forming motion of the forming die. For this purpose, a stop can be provided for the end of the hollow body to be formed that lies in the direction of the forming motion. Alternatively or additionally, it is possible, among other things, to effectively fix the hollow body to be formed during the forming motion of the forming die by means of a clamping device in the direction of the forming motion of the forming die.

[0012] Due to the forming movement of the forming die and the associated plastic deformation of the hollow body wall material, the forming mandrel profile section of the cross-sectionally expanded mandrel section is represented as a first wall profile section of the wall profile on the inside of the first longitudinal section of the hollow body wall. On the inside of the second longitudinal section of the hollow body wall, the forming mandrel profile section of the cross-sectionally reduced mandrel section creates a second wall profile section of the wall profile.

[0013] The forming movement of the forming die can be performed in one continuous motion along both the expanded and reduced mandrel sections. However, it is also possible to divide the forming movement of the forming die into separate partial movements. For example, in a first partial movement, the forming die can move along only one of the two mandrel sections, imprinting its mandrel profile section on the inside of a corresponding longitudinal section of the hollow body wall. Then, after a possible repositioning of the forming mandrel along the hollow body wall to be formed, the forming die can move along the other mandrel section in a second partial movement, imprinting the mandrel profile section of the other mandrel section on the inside of a corresponding longitudinal section of the hollow body wall.

[0014] As long as the forming mandrel is still inside the cavity of the formed hollow body, the hollow body provided with the wall profile has a cavity cross-section bounded by the hollow body wall in the area formed by means of the cross-section-enlarged mandrel section, which has an excess compared to the cavity cross-section in the area of ​​the hollow body formed by means of the cross-section-reduced mandrel section.

[0015] The excess of the cross-section-enlarged mandrel section compared to the cross-section-reduced mandrel section is determined by calculation, simulation and / or empirically, depending, for example, on the specific application, in particular on the material properties of the hollow body wall to be formed.

[0016] The excess of the cross-sectionally expanded mandrel section compared to the cross-sectionally reduced mandrel section can be selected such that an elastic recovery of the hollow body wall, which occurs more strongly in the first longitudinal section of the hollow body wall after the forming mandrel is removed from the formed hollow body, is compensated to such an extent that, after the forming mandrel is removed from the formed hollow body, a uniform cavity cross-section, adapted to the cross-section of the counterpart to be received, is permanently obtained along the first and second longitudinal sections of the hollow body wall.

[0017] Alternatively, the excess of the mandrel section with increased cross-section compared to the reduced-cross-section section can be dimensioned such that, after removal of the forming mandrel, an excess of the cavity cross-section remains in the first longitudinal section of the hollow body wall compared to the cavity cross-section of the longitudinal section(s) of the hollow body wall adjacent to the first longitudinal section. This method for dimensioning the excess of the mandrel section with increased cross-section compared to the reduced-cross-section section is preferably used in cases where, after the forming process, an additional component is applied to the outside of the hollow body wall. This component encircles the hollow body wall in a ring-like manner and is pre-tensioned in the circumferential direction to fix it to the hollow body wall, thereby narrowing the cavity cross-section that existed before the application of the additional component.Under the influence of the additional component, the cavity cross-section at the first longitudinal section of the formed hollow body wall adapts to the cavity cross-section in the area of ​​the longitudinal section(s) of the formed hollow body wall adjacent to the first longitudinal section.

[0018] Specific embodiments of the method according to claim 1 and the mechanical arrangement according to claim 8 are set out in dependent claims 2 to 7 and 9 to 11.

[0019] According to claim 2, in a further development of the invention, the forming mandrel is arranged inside the cavity of the hollow body such that the forming mandrel, with its cross-sectionally expanded mandrel section, extends to the level of a first longitudinal section of the hollow body wall provided with the cavity opening. This measure according to the invention is particularly advantageous because, after the forming mandrel is removed from the formed hollow body, a greater elastic recovery of the hollow body wall often occurs in the area of ​​the cavity opening compared to the remaining length of the hollow body wall.

[0020] In a preferred embodiment of the inventive method, as described in claim 3, the forming movement of the forming die is superimposed with a mandrel movement of the forming mandrel that opposes the forming movement of the forming die, wherein the forming mandrel is positively and / or force-fit connected to the hollow body wall during the mandrel movement. The method feature of claim 3 is particularly advantageous in cases where, during the forming movement of the forming die, the hollow body to be formed is at least restrained against movement in the direction of movement of the forming die at the side of the forming die located in the direction of movement.Due to the forming movement of the forming die, the forming mandrel takes plasticized material from the hollow body wall with it in its direction of movement, thereby preventing the hollow body wall from being undesirably compressed in the area located in front of the forming die in the direction of the forming movement.

[0021] In a further development of the machine arrangement according to the invention, a corresponding mandrel drive is provided for moving the forming mandrel (claim 9). The mandrel movement preferably ends with the forming movement of the forming die. The distance traveled by the forming mandrel during the mandrel movement is dimensioned in particular such that it corresponds to the length increase of the hollow body wall resulting from the forming process or slightly exceeds the length increase of the hollow body wall.

[0022] Claims 4 and 6 relate to particularly practically relevant variants of the method according to the invention.

[0023] According to claim 4, a wall profile is formed on the inside of the hollow body wall, with teeth and interdental spaces extending along the hollow body wall. The counterpart to be inserted into the formed hollow body is provided with corresponding mating teeth.

[0024] The features of claim 5, in a further development of the inventive method according to claim 4, enable the production of external teeth on the hollow body to be formed, in addition to the production of internal teeth. The external teeth of the formed hollow body wall can, for example, be used to attach and permanently position an additional component of the aforementioned type on the outside of the hollow body wall.

[0025] According to claim 6, the hollow body to be formed is tubular in shape. The hollow body wall, which is designed as a tube wall, is provided with an internal profile, and, according to the method of claim 5, with internal and external teeth.

[0026] Due to the process, the dimensions of the hollow body wall increase along the axis of movement of the forming die during the forming process according to the invention.

[0027] If the first longitudinal section and the second longitudinal section of the hollow body wall to be formed have a uniform thickness, the first longitudinal section of the hollow body wall will elongate more than the second longitudinal section of the hollow body wall during the forming process, because the forming mandrel interacting with the forming die has a larger cross-section on the first longitudinal section of the hollow body wall than on the second longitudinal section of the hollow body wall.

[0028] To limit the process-related length increase of the hollow body wall during the forming process, claim 7 provides, as a preparatory measure prior to the interaction of the forming die and forming mandrel, a reduction in the thickness of the hollow body wall in the first longitudinal section of the hollow body wall, which is particularly affected by the process-related elongation, compared to the thickness of the hollow body wall in the second longitudinal section of the hollow body wall.

[0029] In a further development of the machine arrangement according to the invention, a device preferably designed as a rotary kneading device for partial thickness reduction of the hollow body wall is provided for reducing the thickness of the first longitudinal section of the hollow body wall (patent claims 10, 11).

[0030] The invention is explained in more detail below with reference to exemplary schematic diagrams. These show: Figure 1 shows a shaft blank for manufacturing a profiled hollow shaft for a motor vehicle, Figure 2 shows a forming mandrel of a forming device for forming the shaft blank according to Figure 1 Figure 3 is a representation illustrating a forming process carried out by means of a machine arrangement for the production of a profiled hollow shaft from the shaft blank according to Figure 1 Figure 4 is a sectional view of the wave blank according to Figure 1 manufactured profiled hollow shaft in a Figure 3 Section plane running along line IV-IV, Figure 5. Illustrations to demonstrate a further one using the machine arrangement according to Figure 3 The forming process carried out to manufacture a profiled hollow shaft from the shaft blank according to Figure 1 and Figure 6 illustrates a process using the machine arrangement according to Figure 3formed process carried out to manufacture a profiled hollow shaft from another shaft blank.

[0031] Figure 1 Figure 1 shows a hollow body in the form of a tube-like corrugated blank 1 with a tube wall 2 forming the hollow body wall. The tube wall 2, which has a circular cross-section, is made of alloy steel and is plastically deformable. It encloses a cavity 3, which is open at both ends and has a cavity opening 4 at one longitudinal end.

[0032] From the shaft blank 1, a profiled hollow shaft 100 for a motor vehicle is manufactured in the manner described below ( Figure 3 ).

[0033] To manufacture the profiled hollow shaft 100, a partial length I of the shaft blank 1 is formed by means of a Figure 3schematically represented machine arrangement 5 is formed and thereby provided on the inside of the tube wall 2 with a wall toothing forming an internal toothing and with a wall toothing forming an external toothing.

[0034] The machine arrangement 5 comprises a forming machine 6 with a forming tool 7, which in turn includes a forming mandrel 8 and a forming die 9.

[0035] The in Figure 2 The forming mandrel 8, shown in isolation, is provided with a forming mandrel profile designed as a forming mandrel toothing 10. The forming mandrel toothing 10 comprises, as a first forming mandrel profile section, a first forming mandrel toothing section 11 on a cross-sectionally enlarged mandrel section 12 of the forming mandrel 8, and as a second forming mandrel profile section, a second forming mandrel toothing section 13 on a cross-sectionally reduced mandrel section 14 of the forming mandrel 8.

[0036] The forming teeth of the first forming mandrel toothing section 11 and the second forming mandrel toothing section 13 have an identical basic geometry. However, the forming teeth of the first forming mandrel toothing section 11 are scaled outwards in the radial direction of the forming mandrel 8 compared to the forming teeth of the second forming mandrel toothing section 13. A continuous transition 15 is formed between the two mandrel toothing sections 11 and 13.

[0037] The forming die 9 has a die opening 16 with a calibration section 17. The forming die 9 is provided with a forming die toothing 18 at the calibration section 17 of the die opening 16.

[0038] In addition to the forming mandrel 8 and the forming die 9, the forming machine 6 includes a motorized, in the illustrated example hydraulic mandrel drive 19 and as a forming drive a motorized and in the illustrated example also hydraulic die drive 20.

[0039] To generate the wall serrations on the partial length I of the pipe wall 2, the forming die 9 is brought to the in by means of the die drive 20. Figure 1 The right end of the shaft blank 1 is moved. Subsequently, the forming mandrel 8 is advanced by means of the mandrel drive 19 through the die opening 16 of the forming die 9 into the cavity 3 of the tube wall 2 until the leading end of the forming mandrel 8 passes over the opening 16 of the forming die 9. Figure 1The left boundary of the partial length I of the pipe wall 2 projects forward and extends with the cross-sectionally enlarged mandrel section 12 at the level of the cavity opening 4 and along a first longitudinal section l 1 of the pipe wall 2 provided with the cavity opening 4. The cross-sectionally reduced mandrel section 14 of the forming mandrel 8 comes to lie on the partial length I of the pipe wall 2 at the level of a second longitudinal section l 2 of the pipe wall 2 following the first longitudinal section of the pipe wall 2 along the pipe wall 2. The resulting positions of the forming mandrel 8 and the forming die 9 are in Figure 1 Indicated by dashed lines.

[0040] In the circumferential direction of the pipe wall 2, the forming mandrel 8 and the forming die 9 are aligned relative to each other such that teeth of the forming die toothing 18 on the pipe wall 2 are opposite tooth spaces of the forming mandrel toothing 10 and tooth spaces of the forming die toothing 18 are opposite teeth of the forming mandrel toothing 10.

[0041] Based on the resulting conditions, the forming die 9 is moved by means of the die drive 20 in the direction of an arrow 21 along the pipe wall 2 passing through the die opening 16 relative to the pipe wall 2 and relative to the forming mandrel 8.

[0042] During the forming movement of the die 9, the shaft blank 1 is held in place by means of a Figure 3 The clamping device 22 of the forming machine 6, which is shown in a highly schematic way, is prevented from moving in the direction 21 of the forming movement of the forming die 9.

[0043] The forming movement of the forming die 9 in the direction of arrow 21 begins when the die opening 16 runs onto the pipe wall 2. Slightly earlier, a mandrel movement of the forming mandrel 8 in the direction of arrow 23 begins, caused by the mandrel drive 19 and directed against the forming movement of the forming die 9.

[0044] With the start of the forming movement of the forming die 9, the pipe wall 2 is pressed by the forming die 9 against the forming mandrel 8, thereby creating a force-fit connection between the pipe wall 2 and the forming mandrel 8.

[0045] Due to the forming movement of the forming die 9, material of the tube wall 2 is plasticized. As a result, the forming die teeth 18 are formed on the outside of the tube wall 2 and the forming mandrel teeth 10 are formed on the inside of the tube wall 2. This creates a wall profile in the form of external teeth 24 on the outside of the tube wall 2 and a wall profile in the form of internal teeth 25 on the inside of the tube wall 2. Figure 4 ).

[0046] Due to the existing force-fit connection, the forming mandrel 8, during its mandrel movement in the opposite direction to the forming movement of the forming die 9, exerts tensile stress on the pipe wall 2 in the direction of arrow 23. This prevents compression of the pipe wall 2, which is fixed by means of the clamping device 22, on the side of the forming die 9 located in the direction 21 of the forming movement.

[0047] Figure 3 shows the conditions at the end of the forming process.

[0048] Due to the process, the length of the tube wall 2 increased during its forming with the forming tool 7. Consequently, the first longitudinal section l1 and the second longitudinal section l2, and thus also the partial length I of the tube wall 2 of the profiled hollow shaft 100 after forming, are each larger than the first longitudinal section l1, the second longitudinal section l2, and the partial length I of the tube wall 2 of the shaft blank 1.

[0049] When the forming mandrel 8 and the forming die 9 are removed from the profiled hollow shaft 100 after the forming process has been completed, the formed tube wall 2 of the profiled hollow shaft 100 elastically returns to its original shape to a certain extent in the radial direction. This elastic return is more pronounced in the first longitudinal section l1 located near the opening 4 of the hollow body than in the area of ​​the second longitudinal section l2 of the tube wall 2.Nevertheless, after removing the forming mandrel 8 and the forming die 9 from the profiled hollow shaft 100, an excess of the cavity cross-section of the first longitudinal section l 1 of the tube wall 2 compared to the cavity cross-section of the second longitudinal section l 2 of the tube wall 2 remains due to the cross-sectional excess of the mandrel section 12 used for forming the first longitudinal section l 1 of the tube wall 2, which was empirically determined in the present example case, compared to the mandrel section 14 used for forming the second longitudinal section l 2 of the tube wall 2.

[0050] This machining result is desirable because, after completion of the profiled hollow shaft 100, an additional component is applied to the profiled hollow shaft 100 in the area of ​​the first longitudinal section l 1. This component surrounds the tube wall 2 of the profiled hollow shaft 100 in the circumferential direction and is pre-tensioned in the circumferential direction, thereby narrowing the cross-section of the cavity 3 of the profiled hollow shaft 100 in the area of ​​the cavity opening 4 after completion of the forming process. In the illustrated example, an additional component is a rotary encoder (not shown) of a device for detecting the rotational position of the profiled hollow shaft 100 on the motor vehicle equipped with the profiled hollow shaft 100.

[0051] The initial cavity cross-sectional excess of the first longitudinal section l 1 compared to the second longitudinal section l 2 of the tube wall 2 of the profiled hollow shaft 100 after completion of the forming process is dimensioned accordingly by fixing the additional component on the outside of the profiled hollow shaft 100, such that it is compensated by fixing the additional component on the outside of the profiled hollow shaft 100 and consequently, after fixing the additional component on the first longitudinal section l 1 and the second longitudinal section l 2 of the tube wall 2 of the profiled hollow shaft 100, an at least approximately uniform cavity cross-section results, which is matched to the cross-section of the externally toothed counterpart to be received by the profiled hollow shaft 100.

[0052] As a further functional unit of the machine arrangement 5, in Figure 3 A device designed as a rotary kneading device 26 for partial thickness reduction of the pipe wall 2 is shown.

[0053] If required, the thickness of the tube wall 2 of the shaft blank 1 in the first longitudinal section l1 can be reduced compared to the thickness of the tube wall 2 in the second longitudinal section l2 by means of the rotary kneading device 26 to prepare for a forming process of the type described above. As a result of the thickness reduction, the first longitudinal section l1 of the tube wall 2 will, as desired, exhibit a reduced increase in length during the forming process compared to the conditions with a uniform wall thickness.

[0054] The in the Figure 5 and 6 The illustrated forming processes are also demonstrated using the in Figure 3 The machine arrangement shown in section 5 was carried out, and also in the Figure 5 and 6The formed shaft blank is fixed against longitudinal movement by means of the clamping device 22 throughout the entire forming process. However, the process sequence and the position of the cross-sectionally expanded longitudinal section of the tube wall 2 on the profiled hollow shaft 100 differ from the process sequence and the process result of Figure 3 .

[0055] As in the case of the forming process according to Figure 3 is also done at the beginning of the forming process according to Figure 5 The forming die 9 is moved to the right end of the shaft blank 1 by means of the die drive 20, and the forming mandrel 8 is advanced through the die opening 16 of the forming die 9 into the cavity 3 of the tube wall 2 by means of the mandrel drive 19. The forming mandrel 8, having been advanced into the cavity 3 of the tube wall 2, also projects with its leading end beyond the Figure 1The left boundary of the partial length I of the tube wall 2 of the shaft blank 1 is defined; inside the cavity 3 of the tube wall 2, the forming mandrel 8 is arranged only with the reduced-cross-section mandrel section 14. The expanded-cross-section mandrel section 12 initially remains outside the cavity 3.

[0056] Starting from this point, the forming die 9 performs a first forming movement in Figure 5 to the left, while at the same time the forming mandrel 8 is moved in the opposite direction to the right in Figure 5. At the end of this first process step, the relationships shown in part (1) of Figure 5 . Using the forming die 9, the entire partial length I of the tube wall 2 of the shaft blank 1 was formed over the cross-section-reduced mandrel section 14 of the forming mandrel 8 and provided with an internal toothing.

[0057] Due to the process, the pipe wall 2 has lengthened. With its partial representation (1) of Figure 5At the right end, the formed tube wall 2 extends almost to the transition 15 between the cross-sectionally reduced mandrel section 14 arranged inside the cavity 3 of the tube wall 2 and the cross-sectionally expanded mandrel section 12 of the forming mandrel 8, which is still arranged outside the cavity 3.

[0058] With the forming die 9 remaining in the position of partial representation (1), the forming mandrel 8 is now inserted into Figure 5 moved to the left such that the forming mandrel 8 with the cross-sectionally expanded mandrel section 12 enters the cavity 3 of the pipe wall 2 and consequently widens the cavity 3 of the pipe wall 2 at a right end section of the pipe wall 2 in Figure 5, thereby increasing the outer diameter of the pipe wall 2 (partial illustration (2) of Figure 5 ).

[0059] After completion of the mandrel movement, the forming die 9, which is seated on the pipe wall 2, is moved from its previous position into Figure 5The forming die 9 moves to the right along the pipe wall 2, along the reduced-cross-section mandrel section 14, and—with a second forming movement—along a portion of the expanded-cross-section mandrel section 12 of the forming mandrel 8. During its forming movement over the relevant portion of the expanded-cross-section mandrel section 12, the forming die 9 reduces the outer diameter of the pipe wall 2, previously enlarged by the expanded-cross-section mandrel section 12, back to its original outer diameter in the area it passes through. Simultaneously, the expansion of the cavity 3 inside the pipe wall 2 caused by the expanded-cross-section mandrel section 12 is maintained. The thickness of the pipe wall 2 is consequently reduced over that part of the pipe wall 2 which is located at the level of the part of the cross-sectionally expanded mandrel section 12 passed by the forming die 9.

[0060] At the end of its second forming movement, the forming die 9 is arranged on the end section of the tube wall 2, which has been previously widened by means of the forming mandrel 8, at a distance from the cavity opening 4 (partial illustration (3) of Figure 5 ).

[0061] The forming mandrel 8 does not change its position during the last die movement. A mandrel movement in the opposite direction to the movement of the forming die 9 is unnecessary, since the pipe wall 2, which is still fixed by means of the clamping device 22, is not affected by the movement of the forming die 9. Figure 5 The forming die 9 is subjected to tensile stress as it moves to the right, and therefore no significant compression of the pipe wall 2 is to be feared on the side of the forming die 9 located in the direction of movement of the forming die 9.

[0062] After the forming die 9, which is shown in partial representation (3) of Figure 5Once the shown position has been reached, the forming mandrel 8 is inserted into the forming die 9 with the cross-sectionally enlarged mandrel section 12 while the forming die 9 remains in its position. Figure 5 to the right out of the cavity 3 of the tube wall 2. As a result, the forming mandrel 8 with the cross-sectionally reduced mandrel section 14 comes to lie inside the cavity 3 of the tube wall 2 at the level of the end section of the tube wall 2 that was previously not passed by the forming die 9 (partial illustration (4) of Figure 5 ).

[0063] Finally, the forming die 9 is now removed from its position according to the partial representations (3) and (4) of Figure 5 moved to the right. In doing so, the forming die 9 removes, over the partial length of the end section of the tube wall 2 that it passes through, the defect shown in the process step (2). Figure 5The increase in the outer diameter of the pipe wall 2 is caused by the cross-sectionally enlarged mandrel section 12. Since the forming die 9 moves along the cross-sectionally reduced mandrel section 14, the reduction in the outer diameter does not result in a thinning of the pipe wall 2, but rather in a reduction of the cross-sectional area of ​​the pipe wall 2 in the process step according to partial illustration (2). Figure 5 connected to an enlarged cavity cross-section.

[0064] As a result of the forming process according to Figure 5 The partial representation (6) of Figure 5 The illustrated profiled hollow shaft 100.

[0065] Over its entire length I, the profiled hollow shaft 100 has a uniform outer diameter and external teeth running without offset along the tube wall 2. In two longitudinal sections l 2 of length I, the cavity 3 of the formed tube wall 2 has a uniform cross-section and the tube wall 2 has the same thickness. In a longitudinal section l 1 located between the longitudinal sections l 2 and spaced apart from the cavity opening 4, the cross-section of the cavity 3 of the formed tube wall 2 is larger than the cavity cross-section in the two longitudinal sections l 2. The thickness of the tube wall 2 in the longitudinal section l 1 is less than the thickness of the tube wall 2 in the two longitudinal sections l 2.

[0066] The geometry of according to Figure 6 The reshaped shaft blank deviates from the geometry according to the Figure 3 and 5 machined shaft blank. In particular, it allows the geometry of the according to Figure 6formed shaft blank to the forming mandrel 8 from the in Figure 6 to insert the forming mandrel 8 into the shaft blank from the left side so far that the forming mandrel 8 with the cross-section-enlarged mandrel section 12 and with the cross-section-reduced mandrel section 14 comes to lie at the level of the part length I of the shaft blank to be formed.

[0067] As in the case of the forming processes according to the Figure 3 and 5 is also done at the beginning of the forming process according to Figure 6 The forming die 9 is moved to the right end of the shaft blank to be formed by means of the die drive 20. The forming mandrel 8 is moved into the forming mandrel by means of the mandrel drive 19. Figure 6 but advanced from the opposite side into the cavity 3 of the pipe wall 2.

[0068] The forming mandrel 8, inserted into the cavity 3 of the tube wall 2, extends with the cross-sectionally enlarged mandrel section 12 along a first longitudinal section l 1 of the tube wall 2, which is arranged at a distance from the longitudinal ends of the shaft blank. The cross-sectionally reduced mandrel section 14 of the forming mandrel 8 comes to rest at the partial length I of the tube wall 2 at the level of a second longitudinal section l 2 of the tube wall 2, which follows the first longitudinal section l 1 of the tube wall 2 along the tube wall 2.

[0069] Based on the resulting conditions, the forming die 9 is driven by the die drive 20 with a forming motion in Figure 6 moved to the left. The forming movement of the forming die 9 is imparted by means of the mandrel drive 19 in Figure 6 The movement of the forming mandrel 8 to the right is superimposed.

[0070] In addition to the force-fit generated by means of the forming die 9, there is also a form-fit between the forming mandrel 8 and the pipe wall 2 at the transition 15 between the cross-section-enlarged mandrel section 12 and the cross-section-reduced mandrel section 14.

[0071] After completion of the forming of the pipe wall 2, starting from the partial representation (1) of Figure 6 In the proportions shown, the forming die 9 moves to the right. The forming mandrel 8 is connected to a Figure 6 taken from the cavity 3 of the now profiled hollow shaft 100 by movement to the left.

[0072] The partial length I of the pipe wall 2 of the partial representation (2) of Figure 6The profiled hollow shaft 100 shown has a longitudinal section l1 and a longitudinal section l2 with a uniform outer diameter and external teeth running without offset in the longitudinal direction of the tube wall 2. The cross-section of the cavity 3 inside the internally toothed tube wall 2 is larger in longitudinal section l1 than in longitudinal section l2. The tube wall 2 is thinner in longitudinal section l1 than in longitudinal section l2.

[0073] Even in the run-up to the events in the Figure 5 and 6 In the illustrated forming processes, the thickness of the pipe wall 2 to be formed can be reduced by means of the rotary kneading device 26 of the machine arrangement 5 in the area which is assigned to the cross-sectionally expanded mandrel section 12 of the forming mandrel 8 in the subsequent forming process.

Claims

1. Method for producing a wall profile (25) on an inner side of a plastically deformable hollow body wall (2) of a hollow body (1), wherein the hollow body wall (2) defines a cavity (3) of the hollow body (1) which is open on at least one side forming a cavity opening (4), and wherein the hollow body wall (2) is formed by: • arranging a forming mandrel (8) having a forming mandrel profile (10) inside the cavity (3) of the hollow body (1) such that the forming mandrel (8) with the forming mandrel profile (10) extends along the hollow body wall (2), and • arranging a forming die (9) provided with a die opening (16) on the outside of the hollow body (1) and forming it along the hollow body wall (2) passing through the die opening (16) relative to the hollow body wall (2) and relative to the forming mandrel. (8) is moved, whereby the wall profile (25) is created on the inside of the hollow body wall (2),by plasticizing material of the hollow body wall (2) due to the forming movement of the forming die (9) and by mapping the forming mandrel profile (10) on the inside of the hollow body wall (2) as the wall profile (25), characterized by that the forming mandrel (8) is arranged inside the cavity (3) of the hollow body (1) such that the forming mandrel (8) extends at the level of a first longitudinal section (l1) of the hollow body wall (2) with a cross-sectionally enlarged mandrel section (12) which has a forming mandrel profile section (11) and a cross-sectional interference compared to a cross-sectionally reduced mandrel section (14) which extends at the level of a second longitudinal section (l2) of the hollow body wall (2) following the first longitudinal section (l1) of the hollow body wall (2) and has a further forming mandrel profile section (13) and thatThe forming die (9) is moved during the forming movement relative to the hollow body wall (2) and relative to the cross-sectionally expanded mandrel section (12) and relative to the cross-sectionally reduced mandrel section (14) of the forming mandrel (8), whereby, due to the forming movement of the forming die (9), - on the inside of the first longitudinal section (l1) of the hollow body wall (2) the forming mandrel profile section (11) of the cross-sectionally expanded mandrel section (12) is depicted as a first wall profile section of the wall profile (25) and - on the inside of the second longitudinal section (l2) of the hollow body wall (2) the forming mandrel profile section (13) of the cross-sectionally reduced mandrel section (14) is depicted as a second wall profile section of the wall profile (25).

2. Method according to claim 1, characterized by the fact thatthe forming mandrel (8) is arranged inside the cavity (3) of the hollow body (1) such that the forming mandrel (8) with the cross-sectionally expanded mandrel section (12) extends at the level of a first longitudinal section (l1) of the hollow body wall (2) provided with the cavity opening (4).

3. Method according to any one of the preceding claims, characterized by the fact that The forming movement of the forming die (9) is superimposed with a mandrel movement of the forming mandrel (8) directed in the opposite direction to the forming movement of the forming die (9), wherein the forming mandrel (8) is positively and / or force-fit connected to the hollow body wall (2) during the mandrel movement.

4. Method according to any one of the preceding claims, characterized by the fact thata wall profile (25) is formed on the inside of the hollow body wall (2) with teeth and interspaces extending along the hollow body wall (2), • wherein the forming mandrel (8) as a forming mandrel profile (10) has a forming mandrel toothing with mandrel teeth and interspaces that open towards the inside of the hollow body wall (2),• wherein the cross-sectionally expanded mandrel section (12) has a forming mandrel toothing section as a forming mandrel profile section (11) and the cross-sectionally reduced mandrel section (14) has a further forming mandrel toothing section as a further forming mandrel profile section (13) and • wherein, due to the forming movement of the forming die (9), - on the inside of the first longitudinal section (l1) of the hollow body wall (2) the forming mandrel toothing section (11) of the cross-sectionally expanded mandrel section (12) is formed as a first wall toothing section of the wall toothing and - on the inside of the second longitudinal section (l2) of the hollow body wall (2) the forming mandrel toothing section (13) of the cross-sectionally reduced mandrel section (14) is formed as a second wall toothing section of the wall toothing.

5. Method according to claim 4, characterized by • thatthe forming die (9) is provided at the die opening (16) with a forming die toothing (18) with die teeth and with matrix tooth spaces that open towards the outside of the hollow body wall (2) passing through the die opening (16) and • that during the forming movement of the forming die (9) die teeth arranged on the outside of the hollow body wall (2) and mandrel tooth spaces arranged on the inside of the hollow body wall (2) as well as matrix tooth spaces arranged on the outside of the hollow body wall (2) and mandrel teeth arranged on the inside of the hollow body wall (2) are opposite each other on the hollow body wall (2),wherein the matrix teeth act on plasticized material of the hollow body wall (2) by forming wall interlocking on the inside of the hollow body wall (2) and also by forming wall interlocking (24) on the outside of the hollow body wall (2) in the direction of the spine tooth spaces opposite the matrix teeth.

6. Method according to any one of the preceding claims, characterized by the fact that the wall profile (25) is produced on the inside of a plastically deformable tube wall of a tubular hollow body (1), wherein the tube wall limits the cavity (3) of the tubular hollow body (1) which is open on at least one side forming the cavity opening (4).

7. Method according to any of the preceding claims, characterized by the fact thatBefore the transformation of the hollow body wall (2), the thickness of the hollow body wall (2) in the first longitudinal section (l1) of the hollow body wall (2) is reduced compared to the thickness of the hollow body wall (2) in the second longitudinal section (l2) of the hollow body wall (2).

8. Machine arrangement for producing a wall profile (25) on an inner side of a plastically deformable hollow body wall (2) of a hollow body (1) with a cavity (3) bounded by the hollow body wall (2), which is open on at least one side forming a cavity opening (4), wherein the machine arrangement comprises a forming device (6) for forming the hollow body wall (2), • with a forming mandrel (8) having a forming mandrel profile (10) and which can be arranged in the interior of the cavity (3) of the hollow body (1) such that the forming mandrel (8) with the forming mandrel profile (10) extends along the hollow body wall (2), • with a forming die (9) which is provided with a die opening (16) and which can be arranged on the outside of the hollow body (1), and • with a forming drive (20).by means of which the forming die (9) arranged on the outside of the hollow body wall (2) can be moved with a forming movement along the hollow body wall (2) passing through the die opening (16) relative to the hollow body wall (2) and relative to the forming mandrel (8), wherein the wall profile (25) can be produced on the inside of the hollow body wall (2) by plasticizing material of the hollow body wall (2) due to the forming movement of the forming die (9) and the forming mandrel profile (10) being formed on the inside of the hollow body wall (2) as the wall profile (25), characterized by thatthe forming mandrel (8) has a cross-sectionally expanded mandrel section (12) and a cross-sectionally reduced mandrel section (14), wherein the cross-sectionally expanded mandrel section (12) and the cross-sectionally reduced mandrel section (14) each have a forming mandrel profile section (11, 13) and wherein the cross-sectionally expanded mandrel section (12) has a cross-sectional interference compared to the cross-sectionally reduced mandrel section (14), that the forming mandrel (8) can be arranged inside the cavity (3) of the hollow body (1) such that the forming mandrel (8) extends at the level of a first longitudinal section (l1) of the hollow body wall (2) with the cross-sectionally enlarged mandrel section (12) and at the level of a second longitudinal section (l2) of the hollow body wall (2) following the first longitudinal section (l1) of the hollow body wall (2) along the hollow body wall (2) with the cross-sectionally reduced mandrel section (14) and thatThe forming die (9) is movable by means of the forming drive (20) during the forming movement along the hollow body wall (2) relative to the cross-sectionally expanded mandrel section (12) and relative to the cross-sectionally reduced mandrel section (14) of the forming mandrel (8), such that, due to the forming movement of the forming die (9), the forming mandrel profile section (11) of the cross-sectionally expanded mandrel section (12) is formed as a first wall profile section of the wall profile (25) on the inside of the first longitudinal section (l1) of the hollow body wall (2), and the forming mandrel profile section (13) of the cross-sectionally reduced mandrel section (14) is formed as a second wall profile section of the wall profile (25) on the inside of the second longitudinal section (l2) of the hollow body wall (2).

9. Machine arrangement according to claim 8, characterized by the fact thata mandrel drive (19) is provided, by means of which the forming mandrel (8) can be moved with a mandrel movement superimposed on and opposite to the forming movement of the forming die (9), wherein the forming mandrel (8) is positively and / or force-fit connected to the hollow body wall (2) during the mandrel movement.

10. Machine arrangement according to claim 8 or claim 9, characterized by the fact that a device (26) for partial thickness reduction of the hollow body wall (2) is provided, by means of which, prior to the forming of the hollow body wall (2), the thickness of the hollow body wall (2) in the first longitudinal section (l1) of the hollow body wall (2) can be reduced compared to the thickness of the hollow body wall (2) in the second longitudinal section (l2) of the hollow body wall (2).

11. Machine arrangement according to claim 10, characterized by the fact that the device (26) for partial thickness reduction of the hollow body wall (2) is designed as a rotary kneading device.

Images