EP3345694A1 - Method and device for locally thickening and thereby producing a hollow body - Google Patents

Abstract

The hollow body wall (22) of a hollow body (23) is thickened in sections. In radial support on an outer mold (15) and on an inner support body (7) of the hollow body (23) by means of two Beaufschlagungsorgane (4, 6) acted upon in an axial direction and compressed. Material of the hollow body wall (22) is plasticized between the Beaufschlagungsstellen in the region of an escape space (21) of the outer mold (15) and plasticized material of the hollow body wall (22) flows under thickening of the hollow body wall (22) in the escape space (21) of the outer mold (15). , As part of a manufacturing process for producing a hollow body (23), the above method is used. A device (16) for partially thickening a plastically deformable hollow body wall (22) of a hollow body (23) is designed to carry out the method mentioned above. A machine (1) for manufacturing a hollow body (23) has a device of the type mentioned.

Description

The invention relates to a method and a device for the particular sectional thickening of a plastically deformable hollow body wall of a hollow body, wherein the hollow body wall along an axis of a cavity bounded by the hollow body wall cavity of the hollow body extends in an axial direction.

The invention further relates to a manufacturing method for manufacturing a hollow body, in which use is made of the above method and a machine for manufacturing a hollow body having a device of the above type.

The need to thicken a hollow body wall of a hollow body, for example, in cases in which the hollow body wall must have an increased rigidity at least in a partial area and / or in cases where a certain area of the hollow body wall with special functional devices, about to be provided with a toothing or with a thread. Hollow body of this type, for example, hollow shafts, as used in automotive engineering as drive shafts and thereby among other things as side shafts.

At present, methods and devices are used by means of which hollow sections of different wall thickness are produced on hollow shafts by reducing the wall of a shaft blank in one axial section while retaining the original wall thickness in another axial section of the shaft blank. Specifically, methods of cold working, such as rotary swaging, may be used.

The object of the present invention is to provide alternative methods and apparatus for the particular sectional thickening of a plastically deformable hollow body wall of a hollow body and for the production of a hollow body with a particular partially thickened hollow body wall.

This object is achieved according to the invention by the methods according to the independent patent claims 1 and 14 as well as by the devices according to the independent patent claims 16 and 19.

In the case of the invention, material is deliberately accumulated on a hollow body wall. For this purpose, the hollow body in question is arranged with the still-thickened hollow body wall in a receptacle of an outer mold. The recording of the outer shape has a receiving wall which extends on the outside of the receiving body arranged in the hollow body wall in the axial direction. A first part length of the receiving wall extends near the hollow body wall parallel to this and forms an outer support surface for the non-thickened hollow body wall. A second part length of the receiving wall is offset from the first part length of the receiving wall with extension of the receptacle radially outward and limits a formed due to the offset escape space of the outer mold. On the inside of the unthickened hollow body wall, an inner support body is arranged such that it has one on the inside the hollow body wall in the axial direction and thereby in particular parallel to the hollow body wall extending support body surface forms an inner support surface for the hollow body wall. The inner support body and provided on this inner support surface lie in the axial direction both at the level of the outer support surface and at the level of the escape space of the outer mold. In the resulting mutual arrangement of the hollow body or the hollow body wall on the one hand and the outer mold and the inner support body on the other hand, the hollow body is acted upon by two Beaufschlagungsorgane Beaufschlagungsstellen each in the axial direction with a compressive force by the Beaufschlagungsorgane with a compression movement in the axial direction to each other be moved. The loading points on the hollow body are spaced apart in the axial direction and the escape space of the outer shape is arranged between the loading points. Under the effect of the compression movement of the Beaufschlagungsorgane material of the hollow body wall between the Beaufschlagungsstellen in the region of the escape space of the outer mold is plasticized and plasticized material of the hollow body wall flows under thickening of the hollow body wall in the escape space of the outer mold. At the same time, the inner support body preferably ensures that the cross section of the hollow space delimited by the hollow body wall remains essentially unchanged, in particular at the level of the escape space of the outer shape.

The inventive method can be configured in particular as a method of cold forming. Be formed hollow body made of any plastically deformable materials, in particular hollow body having at least walls of plastically deformable metal.

As an inner support body comes, for example, a thorn, as admission organs come stamp in question. As a motor drive for generating the compression movement of the Beaufschlagungsorgane can be provided in particular a controllable hydraulic drive. But also other controllable drive types are conceivable.

Preferably, the motor drive of the Beaufschlagungsorgane two drive units, each of which is associated with one of the Beaufschlagungsorgane and controlled, for example, by means of a numerical control of each other coordinated. The numerical control for the Beaufschlagungsorgane may be integrated into a higher-level device or tool control or in a higher-level machine control.

The reshaped hollow body is preferably open in the axial direction at least one end. Depending on the position which occupies the alternative space of the outer mold with respect to the hollow body wall to be thickened in the axial direction, different axial sections of the hollow body wall can be thickened in the manner described. Thickening of the hollow body wall at one or both ends located in the axial direction is just as possible as a thickening of an axial portion of the hollow body wall spaced from the axial ends.

Particular embodiments of the method and apparatus according to the independent claims will become apparent from the dependent claims 2 to 13, 15, 17 and 18th

As shown in claim 2, various possibilities for generating the compression movement of the Beaufschlagungsorgane complementary or alternatively used according to the invention. In detail, it is provided that is moved by appropriate control of the motor drive of the loading members of one of the Beaufschlagungsorgane towards the other, in the axial direction stationary Beaufschlagungsorgan and / or that both Beaufschlagungsorgane simultaneously and thereby moved in opposite directions in the axial direction and / or that both admission bodies are moved simultaneously and at the same time and at different speeds in the axial direction. In any case, the spacing of the loading members in the axial direction decreases and the hollow body wall is pressurized and plasticized in a region arranged between the loading points. The plasticized material of the hollow body wall is through the inner support body prevented from escaping into the cavity interior and thus flows with thickening of the hollow body wall in the arranged on the outside of the hollow body wall alternative space of the outer mold.

According to claim 3 further development of the invention, the possibility to produce by appropriate control of the motor drive of the Beaufschlagungsorgane a continuous compression movement and / or an intermittent compression movement of the Beaufschlagungsorgane. A continuous compression movement is associated with a continuous flow of material, an intermittent compression movement with an intermittent flow of material into the escape space of the outer mold.

The compression movement or the motor drive of the Beaufschlagungsorgane can be controlled according to the invention and / or force controlled (claim 4). In particular, a combination of path control and force control is possible.

In the path control of the compression movement, the path length can be specified, via which the Beaufschlagungsorgane be moved towards each other for the plasticization of material of the reshaped hollow body wall in the axial direction. The basis for the force control of the compression movement may be the amount of the forming force, which is introduced by means of the Beaufschlagungsorgane in the reshaped hollow body wall. Exceeds the amount of forming force a predetermined limit, the compression movement of the Beaufschlagungsorgane can be terminated by appropriate control of the motor drive the Beaufschlagungsorgane. Exceeding the predetermined limit of the forming force, for example, as soon as the escape space of the outer mold is completely filled with plasticized material of the hollow body wall and consequently under the effect of the force exerted by the Beaufschlagungsorganen on the hollow body wall pressure no further plasticized wall material can flow into the escape space. If there is the possibility of increasing the escape space, an increase in the escape space may be initiated upon reaching or shortly before reaching the limit value of the forming force and thereby the condition is created that further plasticized wall material can flow into the escape space.

Both the path length to be defined in the path control of the compression movement and the limit value of the deformation force in the force control of the deformation processes can be determined empirically in particular.

In principle, it is possible to act on the hollow body at arbitrary points along the cavity area of the cavity bounded by the hollow body wall with opposing pressure forces. According to the invention, according to claim 5 is preferably a pressurization of the hollow body at least one of the well-accessible for the forming end end radial end faces of the hollow body, in particular the hollow body wall.

In the interest of compact design as possible of the device according to the invention for thickening the hollow body wall is provided that the hollow body is acted upon by an integrally formed with the inner supporting body Beaufschlagungsorgan in the axial direction with a compressive force (claim 6).

If one of the Beaufschlagungsorgane formed as a hollow organ and provided with a running in the axial direction of the organ cavity, so can enter the organ cavity of the respective Beaufschlagungsorgans in the compression movement of the Beaufschlagungsorgane the inner support body. If the cross-section of the organ cavity and the cross-section of the inner support body are matched and the cooperating with the hollow member is integrally formed with the inner support body, the two Beaufschlagungsorgane are in the compression movement through the received in the organ cavity inner support body in the axial direction relative to each other guided (claim 7).

In a further preferred embodiment of the invention, the hollow body is acted upon in the axial direction by a Beaufschlagungsorgan, which projects radially outwardly from the outside of the hollow body wall and limits the escape space of the outer mold in the axial direction (claim 8). In this case, in particular a force control of the compression movement of the loading members can be realized. If due to the compression movement of the loading members material of the hollow body wall plasticized in an extent and supplied to the escape space of the outer mold, due to which the escape space of the outer mold is completely filled with plasticized wall material, so causes continued pressurization of the hollow body wall by the Beaufschlagungsorgane a pressure increase or an increase of means the Umformkraft exerted the loading force, which signals the control of the motor drive the Beaufschlagungsorgane that currently the thickening of the hollow body wall is completed.

Limits a Beaufschlagungsorgan the escape space of the outer shape in the axial direction, it can be changed by a performed in the axial direction relative movement of the respective Beaufschlagungsorgans on the one hand and the outer shape on the other hand, the axial extent of the escape space, in particular increased.

In a further development of the invention, it is provided for this purpose that in addition to the compression movement of the Beaufschlagungsorgane an axial relative movement of the Beaufschlagungsorgane on the one hand and the outer mold on the other hand in the axial direction is executed (claim 9). About the amount of axial relative movement of the Beaufschlagungsorgane and the outer shape, the axial extent of the thickening produced on the hollow body wall can be defined. Preferably, the axial relative movement of the Beaufschlagungsorgane and the outer shape is carried out by means of a controlled motor drive.

To produce the axial relative movement of the Beaufschlagungsorgane and the outer shape according to the invention provide various options. According to claim 10 is carried out an axial movement of the outer mold and thereby preferably superimposed on a compression movement of the Beaufschlagungsorgane. Due to the mutual superposition of the compression movement of the loading members and the axial movement of the outer mold flows through the compression movement of the loading members plasticized material of the hollow body wall in the steadily increasing due to the axial relative movement of the Beaufschlagungsorgane and the outer shape Ausweichraum the outer mold, where consequently the thickening of the hollow body wall continuously can build up over the desired axial length.

After completion of the deformation of the hollow body wall in a preferred embodiment of the invention, the thickened hollow body wall or the hollow body and the outer mold separated by a one of the thickened hollow body wall or the hollow body and the outer shape executed in the axial direction relative movement (claim 11).

Additionally or alternatively, the invention provides that the thickened hollow body wall or the hollow body is removed from the outer mold, by formed by dividing the outer shape in the axial direction formed outer mold parts in the radial direction by opening the outer mold relative to each other (claim 13). The last-mentioned approach is chosen in particular when the geometry of the deformed hollow body does not permit a removal of the hollow body from the outer shape solely by a movement in the axial direction.

This is the case, for example, when the hollow body wall in the external form during the forming process at the same time or successively with a plurality of thickened in the axial direction thickening, in particular with thickening at both axial ends of the hollow body wall is provided (claim 12). After completion of the forming process, the generated thickenings are at both axial ends of the first part length of the provided on the outer mold receiving wall in the radial direction relative to the cross-section reduced first partial length of the receiving wall compared to the thickening in front. Due to the excess of the cross section of the thickenings of the hollow body wall relative to the cross section of the first part length of the receptacle for the hollow body wall, the thickenings of the hollow body wall can pass the first part length of the receptacle for the hollow body wall in any of the two axial directions of movement.

For cases of the last-mentioned type, the device according to the invention has the outer shape divided in the axial direction. The formed by the division of the outer shape outer moldings are, preferably by means of a controllable motor drive, in the radial direction relative to each other movable (claim 17). By relative movements of the outer mold parts in the radial direction, the outer mold can be selectively opened or closed.

In a further preferred embodiment of the device according to the invention is evidenced by patent claim 18 a formed by division of the outer shape in the radial direction first axial outer mold part in the axial direction in outer moldings, which are movable relative to each other, preferably by means of a controllable motor drive in the radial direction. The first axial outer molded part has the first, reduced cross-sectional partial length of provided on the outer mold receptacle for the hollow body wall. In addition to the first axial outer molded part results due to the radial division of the outer shape, a second axial outer molded part. The second axial outer mold part is integrally formed and provided with the escape space of the outer mold, wherein the escape space at the second axial outer mold part opens to the first axial outer mold part and the wall of the escape space in the axial direction extends such that the second axial outer mold part and in the thickening space formed thickening of the hollow body wall under the emergence of the thickening of the hollow body wall from the second axial outer mold part relative to each other in the axial direction are movable. The two axial outer mold parts are adjacent to each other in the axial direction. In the interior of the two axial outer moldings, the first part length of the receiving wall and the escape space complement each other to the entire receptacle provided for the hollow body wall or the hollow body. Due to its integral nature, the second axial outer mold part free of joints. This circumstance is advantageous in that when thickening a hollow body wall due to the lack of joints no joints are undesirably displayed on the thickening of the hollow body wall generated in the escape space of the outer mold. Since only the alternative space is provided by the receiving of the hollow body wall receiving the outer shape of the second axial outer mold part, so that part of the receptacle which is not reduced cross-section compared to a thickening of the hollow body wall generated in the alternative space of the outer mold, the formed hollow body by a Movement in the axial direction can be removed from the second axial outer mold part.

Figuren 1A bis 4B

den Ablauf einer ersten Variante eines Verfahrens zum abschnittweisen Verdicken einer Wand einer Hohlwelle,

Figuren 5A bis 8B

den Ablauf einer zweiten Variante eines Verfahrens zum abschnittweisen Verdicken der Wand einer Hohlwelle und

Figuren 9A bis 12B

den Ablauf einer dritten Variante eines Verfahrens zum abschnittweisen Verdicken einer Wand einer Hohlwelle.

The invention will be explained in more detail below with reference to exemplary schematic illustrations. Show it:

FIGS. 1A to 4B

the sequence of a first variant of a method for the partial thickening of a wall of a hollow shaft,

FIGS. 5A to 8B

the sequence of a second variant of a method for partially thickening the wall of a hollow shaft and

FIGS. 9A to 12B

the sequence of a third variant of a method for partially thickening a wall of a hollow shaft.

According to Figure 1A has a hinted and designed as a forming machine 1 machine on a first tool holder 2 and a second tool holder 3. In the first tool holder 2, a punch 4 is fixed, the second tool holder 3 holds a processing unit 5, which in turn consists of a pressure piece 6 and one integral with the pressure piece 6 and with respect to the pressure piece 6 cross-section reduced mandrel 7. The mandrel 7 has as well as the pressure piece 6 has a circular cross-section. Due to the cross-sectional reduction of the mandrel 7 relative to the pressure piece 6, the pressure piece 6 forms a circumferential shoulder 8.

The punch 4 and the pressure piece 6 of the processing unit 5 form Beaufschlagungsorgane, wherein the punch 4 is formed as a hollow organ and has a punch cavity 9 as an organ cavity. The punch cavity 9, like the mandrel 7, has a circular cross-section. The cross-sectional size of the punch cavity 9 exceeds the cross-sectional size of the mandrel 7 minimally.

By means of a motor drive unit 10, the punch 4 can be moved along a movement axis 11. In a corresponding manner, a motor drive unit 12 serves to move the processing unit 5 along the movement axis 11. Both in the motor drive unit 10 and in the motor drive unit 12 is in the illustrated example, a hydraulic drive of conventional design. Together, the motor drive units 10, 12 form a motor drive 13 for the punch 4 and the processing unit 5 and thus for the pressure piece 6 and the mandrel 7. A programmable numerical control 14 of the motor drive 13 and the motor drive units 10, 12 is in Figure 1A hinted at.

Together with a provided as an outer shape reinforcement 15 of the punch 4 and the processing unit 5 form a forming tool 16. The forming tool 16 is in all of FIGS. 1A to 8B shown, while the remaining parts of the forming machine 1 for the sake of simplicity only in Figure 1A are shown.

The reinforcement 15 has a receptacle 17 with a receiving wall 18. The receiving wall 18 extends parallel to the movement axis 11 of the punch 4 and the processing unit 5 and comprises a first part length 19 and a subsequent to the first part length 19 along the axis of movement 11 and compared to the first part length 19 with extension of the receptacle 17 radially outwardly offset second part length 20. The second part length 20 of the receiving wall 18 defines an alternative space 21 of the reinforcement 15. The relevant drawing detail "A" of Figure 1A is in FIG. 1B shown enlarged.

The forming tool 16 serves as a device for sectionwise thickening of a plastically deformable hollow body wall of a hollow body, in the illustrated example for the sectional thickening of a plastically deformable steel wall 22 of a hollow shaft 23. The wall 22 defines a circular cross-section cavity of the hollow shaft 23. The axis of movement 11 coincides with the cavity axis of the cavity and defines with its course an axial direction.

The FIGS. 1A to 4B illustrate the sequence of a first by means of the forming machine 1 or by means of the forming tool 16 feasible method for sectionwise thickening of the wall 22 of the hollow shaft 23. Against this method modified methods are based on the FIGS. 5A to 8B as well as on the basis of FIGS. 9A to 12B explained. The different process stages are in each case shown both with an overall view of the forming tool 16 and with an enlarged drawing detail "A". The numbering of the overall views has the addition A, the numbering of the enlarged drawing details is provided with the addition B.

In the case of the process variants according to the FIGS. 1A to 4B and 5A to 8B First, the hollow shaft 23 located in the undeformed state is pushed from the side of the punch 4 in the axial direction (along the movement axis 11) into the receptacle 17 of the reinforcement 15 and thereby onto the mandrel 7 of the processing unit 5 already arranged in the receptacle 17 , The punch 4 is reset at this time with respect to the reinforcement 15 in the axial direction. The processing unit 5 takes against the armor 15 in the axial direction in the Figures 1A . 5A shown position.

The wall 22 of the hollow shaft 23 has in the illustrated example an annular cross-section. The outer diameter of the wall 22 corresponds to the diameter of the receptacle 17 on the reinforcement 15 and coincides with the diameter of the pressure piece 6 of the processing unit 5. The inner diameter of the wall 22 corresponds to the diameter of the mandrel 7 of the processing unit 5. The inserted into the receptacle 17 of the reinforcement 15 hollow shaft 23 is therefore seated in the radial direction without play on the mandrel 7. On the outside, the wall 22 of the hollow shaft 23 of the receiving wall 18 of the receptacle 17 is closely adjacent. In the axial direction, the hollow shaft 23 rests with a radial end face 24 of the wall 22 on the shoulder 8 of the pressure piece 6 running around the axis of movement 11.

Based on these conditions, the punch 4 is delivered by means of the motor drive 13 and the motor drive unit 10 in the axial direction to the hollow shaft 23 until a radial end face 25 of the punch 4 at a radial end face 26 of the wall 22 of the hollow shaft 23 for System comes and the hollow shaft 23 is thus clamped with a magnitude small force between the pressure piece 6 and the shoulder 8 of the processing unit 5 on the one hand and the punch 4 on the other hand in the axial direction. The mandrel 7 runs in the movement of the punch 4 with its remote from the pressure piece 6 end in the axial direction in the die cavity 9 a.

The feed movement of the punch 4, which is carried out by means of the motor drive 13 or the motor drive unit 10, can be both path-controlled and force-controlled by the numerical control 14. In the case of a path-dependent control of the punch 4 is moved starting from its initial position over a defined path length in the axial direction. In a force-dependent control, the force increase in the drive train of the punch 4, which results when the punch 4 with the radial end face 25 runs onto the radial end face 26 of the wall 22 of the hollow shaft 23, marks the end of the feed movement.

The described feed movement of the punch 4 is equally in the context of the method according to the FIGS. 1A to 4B and in the context of the procedure under FIGS. 5A to 8B executed. The resulting at the end of the feed movement of the punch 4 ratios are in the FIGS. 1A, 1B and in the FIGS. 5A, 5B shown. Different from each other are the subsequent procedures.

In the context of the method according to FIGS. 1A to 4B is calculated on the basis of the conditions according to FIGS. 1A, 1B from the punch 4 and the pressure piece 6, an upsetting movement in the axial direction is performed by moving the pressure piece 6 in the axial direction toward the punch 4 stationary in the axial direction. Due to the compression movement material of the wall 22 of the hollow shaft 23 between the Beaufschlagungsstellen on the wall 22, ie between the radial end faces 24, 26 of the wall 22, plasticized and plasticized material of the wall 22 flows into the between the Beaufschlagungsstellen or the radial end faces 24, An alternative material flow is prevented on the inside of the wall 22 by the mandrel 7, which acts as an inner support body for the wall 22 of the hollow shaft 23 and the axis-parallel lateral surface of a support body surface or a inner support surface for the wall 22 forms and supported with this surface, the wall 22 of the hollow shaft 23 in the radial direction. Accordingly, on the outer side of the wall 22, the first part length 19 of the receiving wall 18 acts. The first part length 19 of the receiving wall 18 forms an outer support surface for the wall 22 running parallel to the wall 22 and accordingly supports the wall 22 of the hollow shaft 23 likewise in the radial direction from.

The compression movement, that is, the movement performed by the pressure piece 6 relative to the stationary die 4 of the forming tool 16 in the axial direction, ends as soon as the escape space 21 of the reinforcement 15 is filled to form a thickening 27 of the wall 22 with plasticized material of the wall 22 and thus the method stage according to the FIGS. 2A, 2B is reached.

Also for the described compression movement of the punch 4 and the pressure piece 6, both a displacement control and a force control is conceivable. For path control requires the deposit of an example empirically determined travel length of the pressure piece 6 in the numerical control 14 of the motor drive 13. As soon as the pressure piece 6 in the axial direction on has moved the predetermined path length, the motor drive unit 12 used to move the pressure piece 6 is stopped.

In the case of a force control of the compression movement, the motor drive unit 12 is switched off for the pressure piece 6 as soon as by means of a corresponding sensor on the motor drive unit 12 of that increase in the motor drive force is detected, which occurs when the escape space 21 of the reinforcement 15 with plasticized material of Wall 22 is filled and a further feed of the hollow shaft 23 is thus blocked in the axial direction.

Starting from the process stage according to the FIGS. 2A, 2B the punch 4 is steered away by means of the motor drive unit 10 with respect to the radial end face 26 of the wall 22 of the hollow shaft 23 in the axial direction by the path length over which the thickening 27 of the wall 22 in the subsequent forming process in the axial direction should extend.

If the punch 4 has reached its target position in the axial direction, the motor drive unit 10 is stopped and by means of the motor drive unit 12 a new upsetting movement of the type described above is performed. In this case, by means of the motor drive unit 12, the pressure piece 6 again steered away or force-controlled in the axial direction relative to the stationary in this direction punch 4, until due to the previous withdrawal movement of the punch 4 enlarged escape space 21 of the reinforcement 15 again completely with plasticized material of the wall 22 of the hollow shaft 23 is filled and thus the conditions according to the FIGS. 3A, 3B have resulted.

In the manner described, the procedure is repeated until the thickening 27 produced on the wall 22 of the hollow shaft 23 has the desired length in the axial direction. Throughout the intermittently performed upset movement, the pressure piece 6 is above the mandrel 7 in the interior of the punch cavity 9 guided in the axial direction. In the illustrated example case, a thickening 27 is constructed in the escape space 21 of the reinforcement 15 on the wall 22 of the hollow shaft 23, which extends on the outside wave-shaped in the axial direction. In each of the upsetting strokes of the upset of the punch 4 and the pressure piece 6 compression movement of one of the axial shaft portions of the thickening 27 is generated. By subsequent to the forming process post-processing of the thickening 27, if necessary, the waveform can be leveled.

Starting from the in the FIGS. 4A, 4B illustrated conditions at the end of the forming process, the punch 4 in the axial direction relative to the reinforcement 15 at high speed to the starting position, which he had taken before the beginning of the forming process, moved back. At the same time or following the movement of the punch 4, the machining unit 5 is advanced by actuating the motor drive unit 12 together with the seated on the mandrel 7 hollow shaft 23 in the axial direction until the hollow shaft 23 at least partially disposed outside of the reinforcement 15 and thereby accessible for removal from the forming tool 16.

The removal of the formed hollow shaft 23 can be done by machine. For this purpose, clamping shells 28, 29 are used, as in FIG. 4A are shown very schematically. By means of a corresponding numerically controlled drive, the clamping shells 28, 29 in the radial direction of the formed hollow shaft 23 in the direction of in FIG. 4a shown double arrows are delivered.

If the deformed hollow shaft 23 is pushed sufficiently far out of the reinforcement 15 in the axial direction by means of the motor drive unit 12, then the clamping shells 28, 29 are moved in the radial direction of the hollow shaft 23 until they clamp the hollow shaft 23 behind the thickening 27. Now, by operating the motor drive unit 12, the processing unit 5 is moved back in the axial direction and thereby the mandrel 7 is pulled out of the interior of the hollow shaft 23. The mandrel 7 has the hollow shaft cavity Leave 23, the deformed hollow shaft 23 can be removed by means of the clamping shells 28, 29 from the forming machine 1. For this purpose, the clamping shells 28, 29 in the axial direction can be moved and / or pivotally. With a corresponding movement of the clamping shells 28, 29 in the opposite direction can then insert a still undeformed hollow shaft in the forming machine 1 and the forming tool 16 for initiating a further forming process of the type described above.

In the context of the method according to FIGS. 5A to 8B is calculated on the basis of the conditions according to FIGS. 5A, 5B First, a compression movement performed by the pressure piece 6 is moved by means of the motor drive unit 12 in the axial direction relative to the stationary in the axial direction punch 4. Has due to the relative movement of the pressure member 6 and the punch 4, the escape space 21 of the reinforcement 15 filled to form the thickening 27 with plasticized material of the wall 22 of the hollow shaft 23, but now not the motor drive unit 12 is stopped and the punch 4 relative to the radial End face 26 of the wall 22 of the hollow shaft 23 retracted.

Instead, as soon as the escape space 21 of the reinforcement 15 for the first time filled with plasticized material of the wall 22 and accordingly the process stage according to the FIGS. 6A, 6B is achieved, in addition to the movement already in progress of the pressure piece 6, a movement of the punch 4 initiated in the axial direction. The additional movement of the punch 4 is triggered either controlled away, as soon as the pressure piece 6 has moved from its initial position over a defined path length in the axial direction or force controlled as soon as the escape space 21 of the reinforcement 15 is filled with plasticized material of the wall 22 and consequently an increase of the applied by means of the motor drive unit 12 forming force is recorded.

The joint movement of the punch 4 and the pressure piece 6 joins seamlessly to the first movement phase, in which only the pressure piece 6 is moved in the axial direction.

In that phase of the upsetting movement, in which the punch 4 and the pressure piece 6 jointly move in the axial direction, the punch 4 and the pressure piece 6 move in the same direction, but the pressure piece 6 moves at a higher speed than the punch 4. As a result of Speed difference is exerted by means of the punch 4 and the pressure piece 6 on the wall 22 of the hollow shaft 23 in the axial direction of a compressive force, due to which material of the wall 22 is plasticized. Since the punch 4 and the pressure piece 6 move together in the axial direction, and since this movement is carried out relative to the reinforcement 15 stationary in the axial direction, the escape space 21 of the reinforcement 15, which is delimited by the punch 4, increases in the course of the compression movement. The extent of the escape space 21 increases in the axial direction. Plasticized material of the wall 22 flows steadily into the escape space 21. In this way, the thickening 27 is created over the desired axial length at the relevant axial end of the wall 22 of the hollow shaft 23. Through the mandrel 7, the wall 22 is supported on its inside, by the first part length 19 of the receiving wall 18 on its outer side in the radial direction.

The executed as a continuous compression movement relative movement of the punch 4 and the pressure member 6 and the same time carried out with the compression movement relative movement between the punch 4 and the pressure piece 6 on the one hand and the stationary in the axial direction reinforcement 15 on the other hand are controlled so that in the course of Forming process in the axial direction extending escape space 21 of the reinforcement 15 is permanently filled with plastic material of the wall 22 is completely filled. As a result, the thickening 27 is created over its entire axial length with a flat in the axial direction and the wall of the escape space 21 exactly imaging axis-parallel outer surface.

In the FIGS. 7A, 7B is the thickening 27 on the wall 22 of the hollow body 23 relative to the proportions according to the FIGS. 6A, 6B extended in the axial direction, the final length of the thickening 27 has not yet been reached. With its final axial length, the thickening 27 at the respective axial end of the wall 22 of the hollow shaft 23 in the Figures 8A, 8B shown.

Upon reaching the process stage according to the Figures 8A, 8B the speed of the punch 4 is increased by appropriate control of the motor drive unit 10 such that the speed of the punch 4 exceeds the speed of the pressure piece 6. As a result, lifts the punch 4 with its radial end face 25 of the radial end face 26 of the wall 22 and moves at rapid traverse in its from the armor 15 in the axial direction remote starting position. At the same time, the deformed hollow shaft 23 is pushed out of the reinforcement 15 by the processing unit 5, which continues to move in the axial direction, unchanged. The arranged outside the reinforcement 15 hollow shaft 23 may in the manner described above by means of the in Figures 8A, 8B Not shown clamping shells 28, 29 detected and removed from the forming tool 16 and from the forming machine 1. A hollow shaft 23 to be machined can then be fed to the forming tool 16 by means of the clamping shells 28, 29.

Notwithstanding the procedure according to the FIGS. 1A to 4B and according to the FIGS. 5A to 8B For example, the compression movement performed by the punch 4 and the pressure piece 6 can be superimposed by an axial movement performed by the reinforcement 15 in the axial direction relative to the punch 4 and the pressure piece 6. With appropriate control of the axial movement of the reinforcement 15, the extension of the escape space 21 on the reinforcement 15 in the axial direction and the bulge due to the compression movement of the punch 4 and the pressure piece 6 in the escape space 21 building up thickening 27 increases on the wall 22 of the hollow shaft 23 can length in the axial direction.

That in the FIGS. 9A to 12B illustrated method is in its basic procedures with the method according to the FIGS. 1A to 4B and according to the FIGS. 5A to 8B match. Also according to the FIGS. 9A to 12B a wall 22 of a hollow shaft 23 is plasticized by an upsetting movement of a punch 4 and a pressure piece 6 along an axis of movement 11 in an axial direction, and plasticized material of the wall 22 builds up a thickening 27.

Notwithstanding the methods according to the FIGS. 1A to 4B and 5A to 8B is used in the context of the procedure under FIGS. 9A to 12B a thickening 27 at both axial ends of the wall 22 and the hollow body 23 is generated. For this purpose, according to the FIGS. 9A to 12B a forming tool 30 is used, although not in principle but in constructive details of the forming tool 16 of FIGS. 1A to 8B different.

Unlike the forming tool 16 according to the FIGS. 1A to 8B the forming tool 30 has a multi-part reinforcement 31 as an outer shape. The reinforcement 31 is divided in both the radial direction and the axial direction. Due to the division in the radial direction, the reinforcement 31 comprises a first axial outer shaped part in the form of a first armoring unit 32 and a second axial outer shaped part in the form of a second armoring unit 33. The first armoring unit 32 in turn is in the axial direction to form two lateral Außenform- or Arming parts 34, 35 divided. The parting line between the two lateral reinforcing parts 34, 35 of the first reinforcing unit 32 extends in Figure 9A perpendicular to the plane of the drawing along the movement axis 11. A division of the first armoring unit 32 in more than two, in particular in four or six lateral Außenformbeziehungsweise armoring, is conceivable.

The second reinforcing unit 33 of the reinforcement 31 is integrally formed.

Of the provided on the reinforcement 31 receptacle 17 for the wall 22 of the hollow shaft 23 is at the second Armierungseinheit 33 only one Part of the escape space 21 arranged, the wall of which runs axially parallel in the axial direction. The first armoring unit 32 has the first part length 19 of the receiving wall 18 and a transitional area between the first part length 19 of the receiving wall 18 and the part of the escape space 21 provided on the second arming unit 33. By means of a numerically controlled motorized actuator of conventional design (not shown) the lateral reinforcing members 34, 35 of the first reinforcing unit 32 for opening and closing the armor 31 are moved relative to each other in the radial direction. In Figure 9A the relative mobility of the lateral Armierungssteile 34, 35 symbolized by double arrows.

In that by the FIGS. 9A, 9B illustrated stage of the performed by means of the forming tool 30 forming process at a axial end of the hollow shaft 23 already a thickening 27 has been created. The forming process in question corresponded in its course one of the above to the FIGS. 1A to 4B and 5A to 8B explained method. The multi-part forming tool 30 was used as the one-piece forming tool 16 of FIGS. 1A to 8B ,

After completion of the thickening 27, the punch 4 of the forming die 30 was moved in the axial direction to a position away from the reinforcement 31. Subsequently, the provided with a thickening 27 hollow shaft 23 was removed from the reinforcement 31. For this purpose, the first mandrel 7 by a corresponding axial movement of the processing unit 5 from the interior of the hollow shaft 23 (in Figure 9A pulled down). With the thickening 27 projecting in the radial direction in relation to the first part length 19 of the receiving wall 18, the hollow shaft 23 was supported on the upper side of the first reinforcing unit 32. Thereafter, the lateral reinforcing members 34, 35 of the first reinforcing unit 32 were moved apart in the radial direction so far that it was possible to pull the bulge 27 in the axial direction out of the escape space 21 on the second reinforcing unit 33 and that the hollow shaft 23 with the Thickening 27 could pass the first armor unit 32 with a movement in the axial direction. Outside the reinforcement 31, the hollow shaft 23 was then rotated by 180 degrees and pushed with the one-sided thickening 27 ahead on the mandrel 7 of the processing unit 5. Together with the mounted on the mandrel 7 and mounted in the axial direction on the pressure piece 6 hollow shaft 23, the processing unit 5 was then inserted in the axial direction in the still open first armor unit 32. The first reinforcing unit 32 was then closed by a corresponding relative movement of the lateral reinforcing members 34, 35 in the radial direction. Finally, by a movement of the punch 4 of the forming tool 30, the unilaterally formed hollow shaft 23 is clamped with an absolute low force between the pressure piece 6 and the shoulder 8 of the processing unit 5 on the one hand and the punch 4 on the other hand in the axial direction. This resulted in the conditions according to the FIGS. 9A, 9B ,

Based on these ratios is after the above to the FIGS. 1A to 4B described and in the FIGS. 10A to 12B illustrated method at the second axial end of the hollow shaft 23, a thickening 27 of the wall 22 created. Alternatively, to produce the second thickening 27 of the wall 22 of the hollow shaft 23 and the method according to the FIGS. 5A to 8B applicable.

After completion of the second thickening 27, the hollow shaft 23 is removed from the reinforcement 31 and then removed from the forming tool 30 and the forming machine 1. The sequences in the removal of the hollow shaft 23 with wall 22 formed on both sides correspond to the sequences described above in detail during the removal of the hollow shaft 23, which has been shaped only at one axial end.

Both the one-sided and the hollow shaft 23 formed at both axial ends can be subjected to post-processing as part of a manufacturing process. In particular, it is conceivable that at the or the thickenings 27 of the wall 22 of the hollow shaft 23 special functional devices, such as a thread or a gear teeth, are created.

Claims (19)

Method for, in particular, section-wise thickening of a plastically deformable hollow body wall (22) of a hollow body (23), wherein the hollow body wall (22) extends in an axial direction along a cavity axis of a cavity of the hollow body (23) delimited by the hollow body wall (22), characterized In that the hollow body (23) with the non-thickened hollow body wall (22) is arranged in a receptacle (17) of an outer shape (15, 31) provided with a receiving wall (18) such that the receiving wall (18) on the outer side of the hollow body wall (18) 22) extends in the axial direction and with a running in the axial direction of the first partial length (19) parallel to the hollow body wall (22) extending outer support surface for the unthickened hollow body wall (22) and with a running in the axial direction of the second partial length ( 20) an escape space (21) of the outer mold (15, 31) limited, wherein the second part length (20) of the receiving wall (18) to form the escape space (21) against the first part length (19) of the receiving wall (18) under extension of Receiving (17) is offset radially outward, • that on the inside of the unthickened hollow body wall (22) an inner support body (7) is arranged such that the inner support body (7) having a on the inside of the hollow body wall (22) extending in the axial direction of the support body surface an inner support surface for the hollow body wall (22) is formed, wherein the inner support surface of the inner support body (7) in the axial direction at the level of the outer support surface and also at the level of the escape space (21) of the outer mold (15, 31) is arranged, That with effective radial support of the unthickened hollow body wall (22) on the outer support surface of the outer mold (15, 31) and with effective radial support of the hollow body wall (22) on the inner support surface of the inner support body (7) of the hollow body (23) by means of two Beaufschlagungsorgane (4, 6) is acted on Beaufschlagungsstellen each in the axial direction with a compressive force by the Beaufschlagungsorgane (4, 6) are moved towards each other with an upsetting movement in the axial direction, wherein the loading points on the hollow body (23) are spaced apart in the axial direction and wherein between the loading locations of the escape space (21) of the outer mold (15, 31) is and That due to the compression movement of the loading members (4, 6) material of the hollow body wall (22) between the Beaufschlagungsstellen in the area of the escape space (21) of the outer mold (15, 31) is plasticized and plasticized material of the hollow body wall (22) with thickening of the hollow body wall ( 22) flows into the escape space (21) of the outer mold (15, 31). A method according to claim 1, characterized in that the Beaufschlagungsorgane (4, 6) are moved towards each other with the compression movement in the axial direction, By one of the loading members (4, 6) being moved in the direction of the other, in the axial direction stationary loading member (4, 6) and / or • By the two Beaufschlagungsorgane (4, 6) are moved simultaneously and in opposite directions in the axial direction and / or • by the two admission bodies (4, 6) are moved simultaneously and simultaneously in the same direction and at different speeds in the axial direction. Method according to one of the preceding claims, characterized in that the Beaufschlagungsorgane (4, 6) are moved towards each other with a continuous compression movement and / or with an intermittent compression movement in the axial direction. Method according to one of the preceding claims, characterized in that the compression movement of the loading members (4, 6) is controlled away and / or force controlled. Method according to one of the preceding claims, characterized in that the hollow body (23) by means of at least one of the Beaufschlagungsorgane (4, 6) at a Beaufschlagungsstelle at an end-side radial end face (24, 26) of the hollow body (23) in the axial direction with a Compressive force is applied. Method according to one of the preceding claims, characterized in that the hollow body (23) by a integrally formed with the inner support body (7) Beaufschlagungsorgan (6) is acted upon in the axial direction with a compressive force. Method according to one of the preceding claims, characterized in that the hollow body (23) is acted upon by a Beaufschlagungsorgan (4) in the axial direction with a compressive force which is formed as a hollow member and extending in the axial direction and at least to the inner support body (7) open towards and for receiving the inner support body (7) formed organ cavity (9) is provided. Method according to one of the preceding claims, characterized in that the hollow body (23) is acted upon by a Beaufschlagungsorgan (4, 6) in the axial direction with a compressive force which protrudes radially outwards relative to the outer side of the hollow body wall (22) and the escape space (21) of the outer mold (15, 31) bounded in the axial direction. A method according to claim 8, characterized in that in addition to the compression movement of the Beaufschlagungsorgane (4, 6) an axial relative movement of the Beaufschlagungsorgane (4, 6) on the one hand and the outer mold (15, 31) on the other hand in the axial direction is carried out, due to the relative axial movement of the Beaufschlagungsorgane (4, 6) and the outer mold (15, 31) changes the existing in the axial direction extension of the escape space (21) of the outer mold (15, 31), preferably increased. A method according to claim 9, characterized in that the axial relative movement of the urging members (4, 6) and the outer mold (15, 31) is carried out by performing an axial movement of the outer mold (15, 31) in the axial direction, wherein the axial movement of the outer mold (15, 31) is preferably superimposed on the compression movement of the loading members (4, 6). Method according to one of the preceding claims, characterized in that the thickened hollow body wall (22) is removed from the outer mold (15, 31) by a relative movement carried out by the thickened hollow body wall (22) and the outer mold (15, 31) in the axial direction , Method according to one of the preceding claims, characterized in that the hollow body wall (22) is successively provided with a plurality of thickened portions (27) offset from one another in the axial direction, by the hollow body wall (22) being displaced in a plurality of offset positions in the axial direction according to the method is thickened according to one of the preceding claims. Method according to one of the preceding claims, characterized in that the thickened hollow body wall (22), optionally the hollow body wall (22) provided with a plurality of thickened portions (27) offset from one another in the axial direction, is removed from the outer mold (31) by division the outer mold (31) in the axial direction formed outer mold parts (34, 35) are moved in the radial direction by opening the outer mold (31) relative to each other. Manufacturing method for producing a hollow body (23) having a hollow body wall (22) delimiting a cavity and extending along a cavity axis of the cavity in an axial direction, in particular for manufacturing a hollow shaft designed as a steering shaft, characterized in that the hollow body wall (22) according to the method according to one of the preceding claims in particular thickened in sections and is thereby provided over a extending in the axial direction length with a thickening (27). Manufacturing method according to claim 14, characterized in that the thickening (27) of the hollow body wall (22) is provided with at least one functional device, for example with a toothing and / or with a thread. Device for in particular sectionwise thickening of a plastically deformable hollow body wall (22) of a hollow body (23), wherein the hollow body wall (22) extends along a cavity axis of a hollow body wall (22) limited cavity of the hollow body (23) in an axial direction, characterized in that the device comprises: An outer mold (15, 31) with a receptacle (17) provided for the hollow body wall (22) which has a receptacle wall (18) assigned to the outer side of the hollow body wall (22), which receptacle has a first partial length (19) extending in the axial direction ) forms an outer support surface for the non-thickened hollow body wall (22) and delimits an escape space (21) of the outer mold (15, 31) with a second partial length (20) extending in the axial direction, wherein the second partial length (20) of the receiving wall (18 ) with the formation of the escape space (21) with respect to the first part length (19) of the receiving wall (18) with extension of the receptacle (17) is offset radially outward, An inner support body (7) assigned to the inside of the hollow body wall (22), which forms an inner support surface for the hollow body wall (22) with a support body surface assigned to the inside of the hollow body wall (22) and extending in the axial direction, wherein the inner support surface of the inner support body (7) in the axial direction at the height of the outer support surface and also at the level of the escape space (21) of the outer mold (15, 31) can be arranged, • two Beaufschlagungsorgane (4, 6) and a controllable motor drive (13) for the Beaufschlagungsorgane (4, 6), wherein the hollow body (23) with effective radial support of the unthickened hollow body wall (22) on the outer support surface of the outer mold (15, 16) and with effective radial support of the hollow body wall (22) on the inner support surface of the inner support body (7) by means of the loading members (4, 6) at the application sites in the axial direction with a compressive force can be acted upon by the urging members (4, 6) being movable towards each other by means of the motor drive (13) with an upsetting movement in the axial direction, wherein the impingement points on the hollow body (23) are spaced apart in the axial direction and between the impacting points of the escape space (21) of the outer mold (15, 31) is arranged and wherein due to the compression movement of the Beaufschlagungsorgane (4, 6) material of the hollow body wall (22) between the Beaufschlagungsstellen in the region of the escape space (21) of the outer mold (15, 31 ) is plasticized and plasticized material of the hollow body wall (22) with thickening of the hollow body wall (22) flows into the escape space (21) of the outer mold (15, 31). Apparatus according to claim 16, characterized in that the outer mold (31) is divided to form a plurality of outer mold parts (34, 35) in the axial direction and that the outer mold parts (34, 35), preferably by means of a controllable motor drive, in the radial direction under opening the outer mold (31) are movable relative to each other. Apparatus according to claim 16, characterized in that the outer mold (31) is divided in the radial direction to form a first axial outer mold part (32) and a second axial outer mold part (33), the one outer support surface for the unthickened hollow body wall (22). forming first part length (19) of the receiving wall (18) on the first axial outer mold part (32) and the Ausweichraum (21) of the outer mold (31) on the second axial outer mold part (33) is provided and that the first axial outer mold part (32) below Forming a plurality of outer mold parts (34, 35) is divided in the axial direction and the outer mold parts (34, 35) of the first axial outer mold part (32), preferably by means of a controllable motor drive, in the radial direction with opening of the first axial outer mold part (32) are movable relative to each other. Machine for manufacturing a hollow body (23) having a hollow body wall (22) delimiting a cavity and extending along a cavity axis of the cavity in an axial direction, in particular for manufacturing a steering shaft designed as a hollow shaft, characterized by the device according to one of claims 16 to 18.

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