DE102019002851A1 - Process for the production of composite parts through a combination of expanding, deep drawing and subsequent massive forming - Google Patents

Abstract

The invention relates to a method for producing a composite part (28) formed from core material (3) and shell material (2) by means of a deep-drawing process (6), wherein in a first process step the shell material (28) covering at least part of the process-based composite part (28) on the outside. 2) is produced by a deep-drawing process (6) from a sheet-metal blank (1), in which the core material (3) is used as a stamp insert for deep-drawing the shell material (2), the shell material (2) and core material (3) in tight Surface contact with each other, and then the preformed hybrid semi-finished product (14) made of deep-drawn shell material (2) and partially enclosed core material (3) is subjected to a joint forming process (13) in which the final shape of the composite part (28) is produced in a plastic-forming manner. Here, the sheet-like blank (1) for the shell material (2) is provided with at least one perforation (17) and the core material (3) in the area of the at least one perforation (17) is expanded and deep-drawn the sheet-like blank (1) so that the covering material (2) in the area of the section (16) of the core material (3) to be coated is applied to the core material (3), after which the core material (3) and the covering material (2) applied to the core material (3) by means of a further joint Massive deformation (13) is further deformed.

Description

The invention relates to a method for manufacturing a composite part formed from core material and shell material by a combination of expansion, deep drawing and subsequent massive forming, in particular extrusion according to the preamble of claim 1.

The production of composite parts is becoming more and more important due to the need to optimize the use of materials for the production of mass-produced parts or also highly stressed components. On the one hand, high-quality materials are becoming more and more expensive or less available in the extraction process; on the other hand, there is a need to design components that are specifically designed to withstand loads, including the materials used. It often happens that certain material properties of the materials used are only required in certain areas of the components, whereas in other areas other or less high material properties are sufficient. So it is e.g. It has long been common practice for hardened components to use metallurgical processes to specifically harden materials only in the e.g. Carry out abrasive areas and not harden other areas. One goes in a similar way e.g. also with the coating of components, e.g. Chemically stressed components are only provided with a protective coating in the areas that impair the material properties.

Such material properties, which are inhomogeneously distributed over the component, are also increasingly required for metallic components that are made from solid blanks or from sheet metal. So it is from the publication, for example "Pressure Welding of Corrosion Resistant Metals by Cold Extrusion" from Journal of Materials Processing Technology 45 (1994), pages 275-280 known to produce bimetallic tubular, cup-shaped or solid components by cold forging. For this purpose, two different preformed solid or tubular blanks are brought into a predetermined position relative to one another and shaped by forward or backward extrusion in a common die by the action of a punch. Through the plastic deformation of the materials during extrusion, the two different materials combine with each other and are simultaneously brought into the new shape. However, the forming processes in this extrusion are quite complex and thus also the flow processes of the two materials involved, so that only limited statements can be made about the exact distribution of the materials in the component produced and thus about the local material properties.

Composite components made of a steel shell and an aluminum core, for example, have a lower weight than conventional steel components with the same strength and wear resistance of the component surface and thus close the gap between light, but less rigid aluminum parts and components made of steel. Gumm (1968) as well as Wagener and Haats (1994) examined the possibility of producing composite components by joint extrusion on the basis of solid semi-finished products in order to combine the advantageous properties of both materials. By placing two starting molds on top of or one inside the other and then extruding them, composites could be made from the pairings steel / aluminum, copper / aluminum, titanium / aluminum and titanium / steel. The disadvantage of the methods used so far, however, is on the one hand the complex preparation of the semi-finished products and on the other hand the relatively high proportion of material in the outer thick-walled partner, so that in the case of the aluminum / steel combination, the weight reduction can only be used to a small extent.

From the EP 2 707 158 B1 a combination of the deep drawing and extrusion processes is known, according to which massive hybrid components can be manufactured from different materials, in which an originally flat sheet metal blank becomes the outer composite partner of the new solid part. For this purpose, a sheet metal blank, for example made of steel, is drawn through a core, for example made of aluminum, directly via a drawing ring into an extrusion die. Then the hybrid blank produced in this way (for example an aluminum core partially coated with steel) is extruded. This deep-drawing composite extrusion has hitherto only ever been able to encase the first shoulder, for example of a shaft or other stepped workpiece, over a short length. Usually, however, waves, for example, have not just one but several steps arranged one behind the other. These paragraphs usually also meet different requirements (for example sealing surface, bearing running surface, surface for shrinking on a gear), so that different outer materials can be used here.

The object of the present invention is therefore to provide a forming method for the production of components with different material properties, with which stepped workpieces can also be coated with different covering materials by forming, not only on the first shoulder but also on further shoulders.

The object of the invention is achieved with regard to the method from the features of claim 1. Further advantageous ones Refinements of the invention emerge from the subclaims.

The invention is based on a method for manufacturing a composite part formed from core material and shell material by means of a deep-drawing process, the shell material covering at least a part of the composite part formed according to the method being produced by a deep-drawing process from a sheet-shaped blank, in which the core material is used as a stamp insert for the Deep-drawing of the shell material is used, the shell material and core material coming into close surface contact with each other, and then the pre-formed hybrid semi-finished product made of deep-drawn shell material and partially enclosed core material is subjected to a joint forming process in which the final shape of the composite part is produced in a plastically forming process. Such a generic method is further developed in that the sheet-like blank for the shell material is provided with at least one perforation and the core material expands and deep-draws the sheet-like blank in the area of the at least one perforation so that the shell material expands in the area of the section to be coated Core material applied to the core material, after which the core material and the shell material applied to the core material are further deformed by means of a further common massive deformation. The perforation of the sheet-like blank makes it possible, for example in the case of core materials with multiple steps, such as those frequently required in shafts or the like, for example in mechanical engineering, but also in other areas of application, not only as in the EP 2 707 158 B1 to cover the foremost stepped shoulder with a covering material and thereby use other material properties of this covering material, but also to do this on further steps of the stepped core material further back. Figuratively speaking, the perforation of the sheet-like blank, together with the positioning of the stepped core material relative to this perforation, ensures that the foremost or even several front steps of the core material pass through the perforation of the sheet-like blank during expansion and deep-drawing, and the sheet-like blank, to put it clearly, so can be pushed far onto the stepped core material until it comes to lie precisely on the step of the core material that is to be coated with the shell material. Without the perforation, the sheet-like blank would quasi get stuck on the first step on the front side of the first paragraph and this front side would also be deep-drawn enveloping. Instead, a suitable diameter ratio between the perforation and the diameters of the front paragraph or the front paragraphs can be used to ensure that the core material expands the sheet-like blank in the area of the perforation, but nevertheless slides onto the stepped core material until it reaches the intended paragraph and there, enveloping this paragraph, can be deep-drawn. This results in an approximately tubular shape of the expanded and deep-drawn shell material on the intended shoulder of the core material, which can then be further processed in a subsequent solid deformation step.

Thus, stepped core materials can also be coated where the steps are compared to e.g. Shaft end lie back, but should also be coated with a covering material.

The core material takes on the function of a conventional deep-drawing punch for deep-drawing the shell material, the shell material being reshaped by expanding and deep-drawing in a press and then covering the core material on the outside at least in sections and thus at least in sections determining the surface properties of the composite part in particular. The resulting composite part is then converted into the desired final contour by a process of massive deformation of the intermediate stage of the composite part produced in this way, for example by extrusion of the hybrid blank produced into or through an extrusion die. By using different materials for the sheet-like shell material and the core material, the method described is particularly suitable for the production of components in which different requirements are placed on the local component properties. Examples of these requirements are a wear-resistant surface with a low mass of the composite part or different thermal conductivities of the core material and shell material. The sheet-like design of the shell material and the deep-drawing process achieve very homogeneous and uniform material properties of the reshaped shell material, since the layer of shell material on the core material remains essentially unchanged in terms of material thickness and material properties compared to the cut of the shell material. This ensures that the layer of the shell material, which determines at least parts of the outer shape of the composite part, has inherently homogeneous properties and this is not disturbed by flow processes during the forming. At the same time, the processing carried out after deep-drawing by means of massive deformation creates an intimate material bond between the shell material and the core material through a material and / or form fit, possibly also a force fit, through which a separation of the shell material and core material of the later composite part is reliably prevented. This allows the material properties of the shell material and core material to be set very specifically on the later composite part ensure that the combination properties of the composite part meet the requirements. The material properties of the core material and the shell material can be selected and combined with one another according to the later requirements for the composite steel, whereby it is of course also conceivable, for example, to design the shell material with multiple layers and, for example, to provide a wear-free surface on the later outer side of the composite part with a corresponding wear-free layer ensure, whereas on the inside of the shell material facing the core material, a layer is provided that bonds particularly well to the core material. Likewise, the core material itself can consist of several layers or sections or also of an inhomogeneous distribution of different materials which have different material properties. For example, it would be conceivable to join a steel material of high toughness with a steel material of high strength to form a core material in advance, which is then joined to the shell material in the manner described. Likewise, for example, the shell material can be made particularly abrasion-resistant, for example from a steel material, whereas the core material consists of a light metal, for example. This can ensure that the overall properties of the composite part have high abrasion resistance in the outer area with a particularly low density and thus low weight in the core material. It goes without saying that very different combinations of different properties of core material and shell material are conceivable, depending on the intended use of the composite part and the available properties of core material and shell material.

It is particularly advantageous that both the sheet-like blank for the shell material and its at least one perforation can have a regular or irregular contoured inner shape and outer shape, since this determines the shape of the expanded and deep-drawn shell material and thereby in turn the shape of the cover of the core material can be influenced in the area of the respective gradation. The contoured inner shape and outer shape can be symmetrical, e.g. circular, but also asymmetrical, such as oval, angular or any shape.

In addition, it is important that the shell material rests on the outside of the core material in a tube-like manner in the area of the section of the core material to be coated and covers the hybrid semifinished product in sections on the radially outer side, with the shell material not covering the hybrid semifinished product at least partially on the face of the core material due to the perforation of the sheet-like blank . This release of the frontal area of the core material through the effect of the perforation during expansion and deep drawing has the effect that the sheet-like blank for the shell material can be pushed onto the core material until the intended step for sheathing is reached and this designated step is then achieved by deep drawing the wrapping material can be wrapped accordingly. As a result, in the area of the intended step of the core material, an approximately tubular sheathing of the sheath material radially surrounding the step is formed, the end area of the core material or also further steps of the core material oriented towards the end face being left free.

In a first advantageous embodiment, the sheet-like blank for the shell material can be expanded and deep-drawn in an expanding deep-drawing die with an essentially conical expanding section and an essentially cylindrical deep-drawing section. Such expanding deep-drawing matrices are basically based on the work of Burgdorf ( Burgdorf, M. - The expansion deep drawing, a new process in forming technology, Annals of the CIRP, 16, pp. 117-122 ) and can be used to widen perforated sheets by means of a punch formed with an oversize compared to the perforation and then to deep-draw them immediately without the more complex solution of conventional deep-drawing using a hold-down device being necessary. Here, a perforated sheet metal is inserted into an essentially conical widening section of the expanding deep-drawing die and positioned with its perforation to match the punch, which then expands the sheet metal in the area of the perforation during its stroke and deforms it to such an extent that it then moves into the essentially cylindrical Deep-drawn section can be deep-drawn. For this purpose, it is advantageous if the sheet-like blank for the shell material is positioned with its perforation in the conical expansion section of the expansion deep-drawing die in such a way that the core material is located above the perforation. As a result, the core material used here as a punch fits into the perforation of the sheet-like blank for the shell material and expands it so that the shell material in the deep-drawn section of the expansion deep-drawing die in the area of the section of the core material to be coated is against the core material in the area of the desired level.

In another embodiment, however, it is also conceivable that the sheet-like blank for the shell material is expanded and deep-drawn through the core material in a conventional deep-drawing device with a drawing ring and hold-down device. Here, the sheet-like blank of the shell material can be placed between a die and a, for example, segmented hold-down device during the deep-drawing process be held. The forming of the sheet-like blank by deep-drawing does not differ significantly from the known deep-drawing of sheet-shaped materials, with the segmented hold-down device, for example, being able to exert a targeted, locally acting tension on the sheet-like blank of the shell material during deep drawing and thus a certain control of the flow of the sheet-like blank of the shell material is achieved.

In a further embodiment, the hold-down device can initially apply such a force to the sheet-like blank for the wrapping material that the sheet-like blank is only widened by the core material in the area of the perforation without the sheet-like blank already interacting with the drawing ring. This has the same effect as with the help of the expansion deep-drawing die, namely that the sheet-shaped blank can slide onto the core material until the intended shoulder is reached and this shoulder is then enveloped by conventional deep drawing. For this purpose, in a further embodiment, following the expansion of the sheet-like blank, the force of the hold-down device is reduced in such a way that the sheet-like covering material expanded in the area of the perforation is deep-drawn in the drawing ring and the covering material lies against the core material in the area of the section of the core material to be coated.

It is particularly advantageous that when the method is used, several sections of the core material can be coated one after the other in terms of the method, in particular also with different shell materials. For this purpose, the method is carried out several times one after the other, each with its own sheet-like blanks and perforations for the respective covering material, so that the covering material created in each case rests against the appropriate shoulder of the core material and envelops it. As a result, e.g. the core material can also be encased in several stages with different wrapping material, which enables the wrapping materials to be designed individually for each paragraph in a precise and intended manner.

It is particularly advantageous if, as the forming process of the massive forming, an extrusion takes place at least that section of the core material that is partially surrounded by the shell material. Such an extrusion can on the one hand be combined directly with deep drawing, in that the extrusion e.g. is then carried out in the same stroke in a downstream extrusion device. Extrusion also leads to a particularly close bond between the core material and the shell material.

It is conceivable here for the composite extrusion to take place against a counter punch in order to limit or prevent the core material from advancing over the shell material. This lead is caused by a velocity gradient in the material flow velocity. The material flow rate decreases from the center of the core material towards the edge zone. As a result, the core material leads the envelope material. This advance can be prevented by using a counter-punch, in that the counter-punch specifically influences the material flow and thereby homogenizes it.

It is also conceivable to influence the lead in that the sheet-like blank of the shell material is variable in its thickness and / or the core material is provided with profiles or shaped elements in order to limit or prevent the core material from running ahead of the shell material. This also influences the material flow in a targeted manner and is therefore homogeneous.

In another embodiment, it is conceivable that the forming process of massive forming takes place at least one forming step according to one of the processes from the group of composite forging, cup backward extrusion, transverse extrusion, forward extrusion, collar upsetting or tapering of the section of the core material partially surrounded by the shell material. Depending on the shape of the composite part to be produced and the initial shape of the core material, a single one of the above-mentioned massive forming processes or a combination of two or more such massive forming processes can be used; it is also conceivable to carry out the massive forming in several stages one after the other.

Furthermore, it can be advantageous if the core material is surrounded by a boundary in such a way that the core material is prevented from bulging radially during the expansion and deep-drawing. This improves the dimensional accuracy of the core material, especially when very differently deformable materials are used for the core material and the shell material.

Furthermore, it is conceivable to reduce the force required for expanding and deep drawing by pushing the sheet-like blank for the casing material during the expansion and deep-drawing. This facilitates the flow processes during expansion and deep-drawing, and the forming is promoted and also controllable.

Furthermore, it can be advantageous if the core material and / or the sheet-like blank for the cladding material, at least in the area of direct contact with one another, with an adhesion-increasing Coating to be covered. To increase the bond, coatings of shell material and core material can be used (for example, a combination of aluminized sheet steel and aluminum core), through which particularly good adhesion of the shell material to the core material is achieved. It would also be conceivable, for example, as an alternative or in addition to an adhesion-increasing coating, to make an insulating or otherwise separating coating between the shell material and the core material, for example to influence a heat transfer or electrical contact between the shell material and the core material.

It is also conceivable that recesses are provided on the core material and / or sheet-like blank for the shell material to improve the bond between core material and shell material. For the secure connection of the core material and the shell material of the composite part, it is particularly advantageous if shaped elements or shapes, preferably undercuts, folds and / or openings or the like, are provided in or on the deep-drawn shell material and / or the core material or are produced during deep-drawing of the shell material where the core material and the shell material form a positive fit. In addition to the pure frictional connection of the shell material and core material and due to different material elasticities, the material composite can be adjusted to the corresponding requirements by means of a composite material as a result of surface pressures and diffusion processes, through undercuts or workpiece flows (for which, for example, the shell material has to be provided with appropriate openings). For example, the core material deformed during extrusion flows into depressions, windows or similar openings in the covering material and thereby, in addition to a frictional connection, also hooks positively with the covering material if corresponding depressions, windows or similar openings are made in the covering material beforehand or are also produced during deep-drawing processing will.

A particularly preferred embodiment of the method according to the invention is shown in the drawing.

• 1a-1e - eine erste Ausgestaltung des erfindungsgemäßen Verfahrens mit einem massiven Kernmaterial und einem blechförmigen Hüllmaterial als Stadienplan beim Aufweiten und Tiefziehen des blechförmigen Rohlings des Hüllmaterials und anschließendem Vorwärts-Fließpressen,
• 2a-2d - eine Variante des Verfahrens gemäß 1 zur Umhüllung von zwei aneinander grenzenden Stufen eines wellenförmigen Kernmaterials in Form eines Stadienplans,
• 3 - ein Stadium des Verfahrens gemäß 1 mit einem formschlüssig ausgebildeten Wellende des Kernmaterials,
• 4 - eine weitere Ausgestaltung des erfindungsgemäßen Verfahrens gemäß 1 unter Verwendung eines Gegenstempels beim Fließpressen zur Beeinflussung der Fließgeschwindigkeiten beim Tiefziehen,
• 5 - eine Gestaltung des blechförmigen Rohlings des Hüllmaterials mit einer wulstartigen Erhöhung zur Beeinflussung der Fließgeschwindigkeiten beim Tiefziehen und entsprechende Auspaarung/ umlaufende Nut, in die die Erhöhung/Aufdickung des Hüllmaterials greift,
• 6 - eine Variante der Gestaltung des Kernmaterials mit einer Einhausung des Kernmaterials zur Stützung bei der Umformung des Rohlings des Hüllmaterials,
• 7 - eine Variante des Verfahrens unter Verwendung einer Tiefzieheinrichtung mit Niederhalter und Ziehring für das Aufweiten und Tiefziehen,
• 8 - beispielhafte Anwendung des erfindungsgemäßen Verfahrens an einer Welle mit mehreren Absätzen zur Umhüllung einzelner Absätze mit blechförmigem Material,
• 9 - beispielhafte Ausgestaltungen des Kernmaterials und den zugehörigen blechförmigen Rohlings des Hüllmaterials zur Bildung unterschiedliche geformter Verbundteile,
• 10 - verschiedene Varianten der Formgebung des blechförmigen Hüllmaterials mit Ausnehmungen und Öffnungen z. B. zur Verbesserung der form- und kraftschlüssigen Verbindung.

Show it:

• 1a-1e - A first embodiment of the method according to the invention with a solid core material and a sheet-like shell material as a stage plan during the expansion and deep-drawing of the sheet-like blank of the shell material and subsequent forward extrusion,
• 2a-2d - a variant of the procedure according to 1 for wrapping two adjacent steps of a corrugated core material in the form of a stage plan,
• 3 - a stage of the procedure according to 1 with a form-fitting shaft end of the core material,
• 4th - Another embodiment of the inventive method according to 1 using a counter punch during extrusion to influence the flow rates during deep drawing,
• 5 - a design of the sheet-like blank of the wrapping material with a bead-like elevation to influence the flow rates during deep drawing and a corresponding mating / circumferential groove in which the increase / thickening of the wrapping material engages,
• 6 - a variant of the design of the core material with a housing of the core material to support the reshaping of the blank of the shell material,
• 7th - a variant of the method using a deep-drawing device with hold-down device and drawing ring for expanding and deep-drawing,
• 8th - Exemplary application of the method according to the invention on a shaft with several paragraphs for wrapping individual paragraphs with sheet-like material,
• 9 - Exemplary configurations of the core material and the associated sheet-like blank of the shell material for the formation of different shaped composite parts,
• 10 - Different variants of the shape of the sheet-like covering material with recesses and openings z. B. to improve the positive and non-positive connection.

In the 1 is a schematic representation of a first embodiment of the method according to the invention with a core material 3 and a sheet-metal blank 1 of the envelope material 2 as a stage plan for expanding and deep drawing a casing 11 from a sheet-like blank 1 of the envelope material 2 and then forward extrusion in a die 12 shown. The device for carrying out the method is constructed in a basically known manner, so that only the procedural features of the device should be mentioned here. The expansion and deep drawing of the blank 1 is done by an upper punch 7th , below which the core material 3 is placed and initially on the blank 1 gets up. The blank 1 of the envelope material 2 has a central perforation in this case 17th and is placed in an expanding deep-drawing die 4th with a cone 9 inserted. The orientation of the holes 17th is chosen so that the perforation is below the shoulder on the front 8th of the core material 3 comes to rest and with this paragraph 8th at the stroke of the punch 7th in the direction 15th can interact. The stamp moves 7th in feed direction 15th downwards, the opposite of the hole becomes 17th slightly larger frontal heel of the core material 3 penetrate the perforation and this perforation as in 1b to recognize expanding deform. With increasing stroke of the punch 7th Then the outer areas of the blank are placed 1 more and more on the walls of the cone 9 and deform into a kind of depression ( 1c ).

Reaches the second paragraph to be wrapped 16 the area of the deep-drawing opening 6 This is how the expanded and preformed shell material becomes 2 with further stroke in direction 15th deep-drawn and then enters the area of the extrusion mold 13 one that is in the extrusion die 12 is trained. This is where the hybrid semi-finished product produced by expanding and deep drawing is made 14th made of Kenmaterial 3 and wrapping material 2 further deformed by forward extrusion. In the extrusion mold 13 are both wrapping material 2 as well as core material 3 extruded in a generally known manner and thereby intimately fixed to one another, so that after the complete stroke the in the 1e recognizable, tubular envelope 11 of the second paragraph 16 of the core material 3 adjusts and thereby the composite part 28 will be produced. That locally around the core material 3 wrapping material arranged around it 11 determines the surface properties of the composite part in this area 28 . For example, the casing material 2 made of a hard and abrasion-resistant material such as steel, whereas the core material 3 consists of a lightweight aluminum. This allows a lightweight composite part 28 can be produced with locally high abrasion resistance.

In the 2 is a variant of the method according to 1 for covering two adjacent steps of a corrugated core material 3 recognizable in the form of a stage plan, according to the wrapping as in 1 the same process again, but now for a paragraph further back 16 of the core material 3 is performed. Here the perforation 17th adjusted in size accordingly, so that the blank 1 with the widened perforation 17th over the already wrapped section 11 on the core material 3 with his heel 8th in the area 16 can get in which the envelope 11 ' should be done like this in 2d can be seen. Otherwise, this process is the same as for 1 already described in detail.

In the 3 is a stage of the procedure according to 1d with a form-fitting shaft end 8th' of the core material 3 to recognize with which the wrapping 11 form-fitting and therefore particularly good at the shaft end 8th' can be set. The shaft end is for this purpose 8th' at the front with a slightly larger diameter than the area of the heel to be wrapped 16 executed, so that the covering applied as described 11 not again from the shaft end 8th' can slide down.

In the 4th is a further embodiment of the method according to the invention 1 using a counter punch 10 to be recognized during extrusion to influence the flow velocities during industrial pressing. It can happen that the core material 3 during extrusion of the hybrid blank 14th in the extrusion mold 13 during the simultaneous deformation of shell material 2 and core material 3 the reshaping of the shell material 2 leads, so it is more deformed than the shell material. This can be explained by a speed gradient of the material flow speed. The material flow rate decreases from the center of the component to the edge zone. The core material 3 This rushes the deformation of the shell material 2 in front. Using a counterstamp 10 this leading is to be prevented. 4th shows therefore a further combination of processes of expanding deep-drawing composite extrusion with a hybrid core produced by conventional deep-drawing composite extrusion 14th (covered, simply stepped shaft) and using the counter punch 10 during composite extrusion. By using a counter-stamp 10 becomes the material flow speed of the wrapping material 2 homogeneous in the forming zone.

In the 5 is an alternative to influencing the lead of the core material 3 a design of the sheet-like blank 1 of the envelope material 2 with a bead-like elevation 18th to influence the flow rates during deep drawing and extrusion. The, for example, circumferential bead-like elevation 18th leads to increased friction during deep drawing and extrusion in the extrusion mold 13 so that the material flow rate of the core material 3 is reduced z. B. to improve the positive and non-positive connection.

The 6 shows a variant of the design of the core material 3 with an enclosure 29 of the core material 3 to support the forming of the blank 1 of the envelope material 2 . Depending on the selected materials for the blank 1 (e.g. steel) and core material 3 (e.g. made of a light metal) it can happen that the much less resilient core material 3 want to bulge and deform inadmissibly before the material of the blank 1 sufficient to encase has transformed. In order to avoid such bulging, the less resilient core material 3 for example through a more resilient tubular housing 29 be supported and thus prevented from bulging.

In the 7th is a variant of the process using a deep-drawing device with a hold-down device 5 and drawing ring 19th for expanding and deep-drawing to be recognized in the case of the sheet metal blank 1 of the envelope material 2 between the one with a draw opening 6 provided pull ring 19th and a hold-down device 5 is held or clamped in a basically known manner, the hold-down 5 as a segmented hold-down device 5 can be designed and one in the plane of the blank 1 locally controlled pressure on the blank 1 can exercise. In the 7th is the starting position before the start of the drawing process of the sheet metal blank 1 of the envelope material 2 to recognize, ie the massive core material 3 lies on the blank without pressure 1 on. Now becomes the upper stamp 7th and with it the massive core material that acts as a stamp 3 vertically from above in the feed direction 15th in the drawing ring 19th pressed, so the blank is 1 little by little further and further into the draw opening 6 of the draw ring 19th pressed in and forms a deepening shape accordingly 1c . This is done before deepening the blank 1 first of all the widening of the perforation 17th of the blank 1 take place when the pressure of the hold-down device 5 is chosen so large that the outer material of the blank 1 cannot flow at first. Only if after completion of the actual widening of the perforation 17th the pressure of the hold-down device 5 is reduced, the outer material of the blank 1 flow and begin the actual deep drawing.

The 8th shows an exemplary application of the method according to the invention on a shaft configuration that is customary in mechanical engineering 30th with wrapping of individual paragraphs 20th , 21st , 22nd , 23 with sheet material 11 , 11 ' and 11 " . In the upper variant of the wave 30th is the respective front shoulder 23 not wrapped up the heels 20th , 21st and 22nd but as described above with sheet material 11 , 11 ,and 11 " been wrapped. In the lower variant of the wave 30th is the respective front shoulder 23 according to the procedure of EP 2 707 158 B1 has also been wrapped. The wave heels 20th , 21st , 22nd , 23 are for example coated with steel with different properties. The inventive method is able to waves 30th with an indefinite number of paragraphs 20th , 21st , 22nd , 23 to coat with different materials (for example paragraph 20th stainless steel 11 , Paragraph 21st with copper 11 'and heel 22nd high strength steel 11 " ). As materials for the core material 3 steel and non-ferrous metals, plastics or WPC are conceivable. For the material of the blank 1 For example, steel and non-ferrous metals, plastics, WPC or multi-material sheet metal materials produced by roll cladding are conceivable. With the newly developed process for expanding deep-drawing composite extrusion, it is possible to create waves 30th with several paragraphs 20th , 21st , 22nd , 23 to sheath and use the material that meets the requirements of the respective paragraph 20th , 21st , 22nd , 23 Fulfills.

The 9 shows a number of purely exemplary configurations of the core material 3 with paragraph 8th and the associated sheet-metal blanks 1 of the envelope material 2 with the corresponding perforation 17th to form different shaped composite parts 28 . As can be seen, both the border of the perforation 17th as well as the outer edge of the sheet-like blanks 1 Symmetrical or asymmetrical is conceivable, and the position of the perforation is also possible 17th not necessarily centrally within the edge of the sheet-like blanks 1 arranged. This depends in each case on the shape of the casing to be produced 2 of the respective paragraph and can be designed in almost any way.

The 10 shows different variants of the shape of the sheet-like casing material 1 with the perforation 17th and with recesses 27 and openings 26th . There is also a thickening 25th on the paragraph 8th to recognize. All of these shapes can be used to define the envelope 2 on the core material 3 to be improved, for example by form fit as with the recesses 27 and openings 26th or by frictional connection as with the thickening 25th .

List of reference symbols

1 -

Blank envelope material

2 -

sheet-like covering material

3 -

Core material

4 -

Expansion deep-drawing die

5 -

Hold-down

6 -

Pull-through opening die

7 -

stamp

8th -

first paragraph core material

9 -

Cone expansion die

10 -

Counterholder

11 -

tubular covering material

12 -

Extrusion die

13 -

Extrusion mold

14 -

Hybrid semi-finished product

15 -

Direction of force punch

16 -

paragraph to be wrapped core material

17 -

Perforation

18 -

bead

19 -

Deep-drawn ring

20 -

Wave heel

21 -

Wave heel

22 -

Wave heel

23 -

Shaft end

24 -

Shaft end coating

25 -

thickening

26 -

opening

27 -

approach

28 -

Composite component

29 -

Enclosure

30 -

wave

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• EP 2707158 B1 [0005, 0008, 0035]

Non-patent literature cited

• "Pressure Welding of Corrosion Resistant Metals by Cold Extrusion" from Journal of Materials Processing Technology 45 (1994), pages 275-280 [0003]
• Burgdorf, M. - The expansion deep drawing, a new process in forming technology, Annals of the CIRP, 16, pp. 117-122 [0013]

Claims (18)

Method for producing a composite part (28) formed from core material (3) and shell material (2) by means of a deep-drawing process (6), the shell material (2) covering at least part of the composite part (28) on the outside by means of a deep-drawing process (6) is made from a sheet-like blank (1), in which the core material (3) is used as a punch insert for deep-drawing the shell material (2), whereby the shell material (2) and core material (3) come into close surface contact with each other, and then this preformed hybrid semifinished product (14) made of deep-drawn envelope material (2) and partially enclosed core material (3) is subjected to a joint forming process (13) in which the final shape of the composite part (28) is produced in a plastic-forming manner. characterized in that the sheet-like blank (1) for the shell material (2) is provided with at least one perforation (17) and the core material (3) expands and deep-draws the sheet-like blank (1) in the region of the at least one perforation (17) that the shell material (2) rests against the core material (3) in the region of the section (16) of the core material (3) to be coated, after which the core material (3) and the shell material (2) applied to the core material (3) by means of another common massive deformation (13) is further deformed. Procedure according to Claim 1 , characterized in that the core material (3) used is a stepped body made of a deformable material, which is to be coated with a shell material (2) at least in the area of individual steps (16). Method according to one of the Claims 1 or 2 , characterized in that the sheet-like blank (1) for the shell material (2) and its at least one perforation (17) have a regular or irregular contoured inner shape and outer shape. Method according to one of the preceding claims, characterized in that the envelope material (2) in the region of the section (16) of the core material (3) to be coated is placed on the outside of the core material (3) in a tubular (11) manner and the hybrid semi-finished product (14) is applied radially Covered on the outside in sections, the shell material (2) not covering the hybrid semifinished product (14) at least in some areas on the end face of the core material (3) due to the perforation (17) of the sheet-metal blank (1). Method according to one of the preceding claims, characterized in that the sheet-like blank (1) for the wrapping material (2) is expanded in an expanding deep-drawing die (4) with an essentially conical expanding section (9) and an essentially cylindrical deep-drawing section (6) and is deep drawn. Procedure according to Claim 5 , characterized in that the sheet-like blank (1) for the shell material (2) is positioned with its perforation (17) in the conical expansion section (9) of the expansion deep-drawing die (4) that the core material (3, 8) located above the perforation (17). Method according to one of the Claims 5 or 6 , characterized in that the core material (3) expands the sheet-like blank (1) for the envelope material (2) in the area of the perforation (17) in the conical expansion section (9) with a pressing force and in the deep-drawn section (6) the expansion deep-drawing The die (4) is deep-drawn so that the shell material (2) rests against the core material (3) in the area of the section (16) of the core material (3) to be coated. Method according to one of the Claims 1 to 4th , characterized in that the sheet-like blank (1) for the shell material (2) is expanded and deep-drawn by the core material (3) in a deep-drawing device with a drawing ring (19) and hold-down device (5). Procedure according to Claim 8 , characterized in that the hold-down device (5) initially acts on the sheet-shaped blank (1) for the shell material (2) with such a force that the sheet-shaped blank (1) is expanded by the core material (3) in the area of the perforation (17) is without the sheet-like blank (1) already interacting with the drawing ring (19). Method according to one of the Claims 8 and 9 , characterized in that subsequent to the expansion of the sheet-like blank (1), the force of the hold-down device (5) is reduced in such a way that the sheet-like casing material (2) expanded in the area of the perforation (17) is deep-drawn in the drawing ring (19) and the covering material (2) rests against the core material (3) in the region of the section (16) of the core material (3) to be coated. Method according to one of the preceding claims, characterized in that several sections (20, 21, 22) of the core material (3) are coated one after the other in terms of the method, in particular also with different covering materials (11, 11 ', 11 "). Method according to one of the preceding claims, characterized in that the forming process of the massive forming is a composite extrusion (13) of at least the portion (16) of the the core material (3) surrounded in sections by the shell material (2). Procedure according to Claim 12 , characterized in that the composite extrusion (13) takes place against a counter punch (10) in order to limit or prevent a leading of the core material (3) relative to the shell material (2). Procedure according to Claim 12 , characterized in that the sheet-like blank (1) of the shell material (2) is variable in its thickness and / or the core material (3) is provided with profiles (25) or shaped elements in order to prevent the core material (3) from running ahead of the shell material ( 2) limit or prevent. Method according to one of the Claims 1 to 11 , characterized in that, as the forming process of the massive forming, at least one forming step according to one of the processes from the group of composite forging, cup backward extrusion, transverse extrusion, forward extrusion, collar upsetting or tapering of the section (16) of the core material (3) surrounded in sections by the shell material (2) he follows. Method according to one of the preceding claims, characterized in that the core material (3) and / or the sheet-like blank (1) for the shell material (2) are covered with an adhesion-increasing coating at least in the area (16) of direct contact with one another. Procedure according to Claim 17 , characterized in that the sheet-like blank (1) for the shell material (2) is coated at least in sections with the material of the core material (3) on the surface facing the core material (3) after deep drawing, in order to create a material bond between this coating of the shell material (2) and the core material (3). Method according to one of the preceding claims, characterized in that recesses (26, 27) on core material (3) and / or sheet-like blank (1) for the shell material (2) to improve the bond between core material (3) and shell material (2) are provided.

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