DE102024001617A1 - Method for producing a connection between joining partners, in particular sheets, made of preferably different materials and corresponding connection - Google Patents

Abstract

The invention relates to a method for producing a connection between joining partners (2, 3) in which a form-fitting and/or force-fitting connection between the joining partners (2, 3) is produced by means of identically designed and interlocked surface structures (8, 9). Here, the surface structures (8, 9) are arranged at the edge in at least one overlapping edge region of the joining partners (2, 3) in the position to be joined, wherein at least the edge region of the first joining partner (2) is deformed by forming such that the thickness dimensions in this edge region are reduced and the surface structures (8, 9) are introduced into the thickness-reduced edge region (7), the surface structures (8, 9) corresponding to the surface structures (8, 9) of the edge region of the first joining partner (2) are introduced into the edge region of the second joining partner (3), and the first and second joining partners (2, 3) are positioned in a section-by-section overlapping manner such that the corresponding surface structures (8, 9) of the edge regions of the two joining partners (2, 3) are aligned with each other, and these edge regions with the surface structures (8, 9) are joined together by forming. become.

Description

The invention relates to a method for producing a connection between joining partners, in particular between sheets, made of preferably different materials according to the preamble of claim 1, and to a corresponding connection according to the preamble of claim 14.

In recent years, there has been a growing trend towards the use of multi-material structures in vehicles. This trend is further intensified by the increased demands for lightweight construction and safety in the area of vehicle bodies. This often necessitates the joining of various sheet metal structures. Joining technology is undergoing significant change in this area, as soft, deformable sheet metal materials often need to be joined with high- or ultra-high-strength materials for crash safety reasons. This is because both good occupant protection in the passenger compartment and energy absorption in the event of a crash by the areas of the vehicle connected to the passenger compartment are desired. The use of welded joints is very problematic in this context, as high-strength body materials, in particular, generally exhibit poor weldability. Currently, welding aluminum and steel materials is not feasible, even though these connections are trending in modern lightweight vehicle bodies.

Another aspect is often completely overlooked in current discussions about lightweight vehicle construction: Mobility systems, particularly vehicle structures, often employ multi-material structures that present insufficient conditions for implementing recycling processes, the so-called R-strategies, due to a wide range of joining methods that are difficult to separate. As a result, car bodies are currently not returned to the recycling loop in a sorted manner. An important question, therefore, is to what extent improved disassembly of these structures can be achieved.

Current joining technologies have significant drawbacks. Welded joints are often difficult to implement with modern lightweight materials and multi-material connections, and at the end of their life cycle, the joints are difficult to separate. Adhesive bonds are associated with many disadvantages, such as aging and limited strength. The relevance of these issues is outlined in the End-of-Life Vehicles Directive (2020). Currently, the separation of materials by type in the body-in-white stage is only partially achievable due to the existing joining methods.

Folded joints are problematic in the realization of butt sheet metal joints, as the forming operations are complex and difficult to use in car body construction.

Rivet and clinch connections, in which sections of material to be joined are pressed together using forming techniques or rivets are inserted into bores of the components to be joined and pressed at the end, only offer a point-like load transfer.

The current state of the art offers several approaches to joining multi-material connections using different joining techniques.

The JP 04 182 007 A It discloses a method for joining sheets of metal that have interlocking structures at their edges, similar to a puzzle piece for connecting the puzzle pieces. However, these structures are butted together.

On the website of RWTH Aachen “ https://www.ibf.rwth-aachen.de/cms/ IBF/Research/Cross-cutting topics/-peqi/Materials-connect/ Aron Ringel describes a joining technique under the heading "Form-locking rolling" that involves clamping surface structures together through forming or casting processes. For this purpose, channel structures are created across the entire surface of one of the surfaces to be joined using a strip profiling rolling mill, and undercuts may be added if necessary. The other joining partner is then fully bonded to this prepared surface using forming or casting processes.

From the US 3131471 A method for joining sheets over a surface using rollers is also known, wherein microstructures are introduced into the sheets before rolling, but these structures are distributed uniformly over the entire surface of the joining partners. The upper and lower sheets each have interlocking structures and are joined together by rolling over these microstructures across their entire surface.

A major disadvantage of these connections is that they can be almost impossible to separate non-destructively, for example for recycling (according to so-called R-strategies) or for repairs, because the sheets completely overlap and are bonded together. While this allows for the joining of sheets of different materials, the resulting multi-material sheets are no better than, for example, welded or bonded sheets, especially with regard to R-strategies.

The object of the present invention is therefore to enable an improvement in the joining of, in particular, sheets made of, for example, different materials which overlap at least partially and in which improved separation from each other is to be made possible, for example for recycling purposes.

The solution to the problem according to the invention is achieved with respect to the method by the characterizing features of claim 1 and with respect to the connection by the characterizing features of claim 14 in conjunction with the features of the respective preamble. Further advantageous embodiments of the invention are set forth in the dependent claims.

The invention relating to the method is based on a method for producing a connection between joining partners, in particular between sheets, made of preferably different materials, in which a form-fitting and/or force-fitting connection between the joining partners is produced by means of identically designed and interlocked surface structures. Such a generic method is further developed in accordance with the invention by arranging the identically formed and interlocking surface structures of the joining partners at their edges in at least one edge region each, which overlaps with each other in the position to be joined of the joining partners, wherein at least the edge region of the first joining partner is deformed by forming technology in such a way that the thickness dimensions in this edge region are reduced and the surface structures are introduced into the thickness-reduced edge region, the surface structures matching the surface structures of the edge region of the first joining partner are introduced into the edge region of the second joining partner, preferably also reducing the thickness dimensions in this edge region, the first and second joining partners are positioned in a section-by-section overlapping manner so that the corresponding surface structures of the edge regions of the two joining partners are aligned with each other, and these edge regions with the surface structures are joined together by forming technology.

• • Der erste Schritt ist die Vorbereitung der Randbereiche der Fügepartner durch einen vorzugsweise umformtechnischen Prozess. Beispielsweise kann mittels Blechmassivumformen durch Walzen oder ein inkrementelles Schmieden die Dicke der Randbereiche verringert und die Oberflächenstrukturen in die Randbereiche der Fügepartner eingebracht werden. Dies erfolgt in der Regel bei beiden Fügepartnern symmetrisch.
• • Im zweiten Schritt werden die Fügepartner zueinander derart positioniert, dass die Oberflächenstrukturen der Randbereiche zueinander passend übereinander zu liegen kommen. Es folgt dann ein zweiter Umformschritt, der die beiden Randbereiche mittels der Oberflächenstrukturen form- und/oder kraftschlüssig miteinander verbindet. Dies wiederum kann durch einen Walzprozess oder ein inkrementelles Umformen mit linearer Werkzeugbewegung erfolgen.

In this process, the two components to be joined, such as sheet metal, are each provided with interlocking surface structures, such as grooves, protrusions, hooks, or similar shapes, in the edge areas to be defined later. These structures can be smooth, perhaps prismatic, in the joining direction, or they can have undercuts and fit together like a key and lock. The thickness of the edge area(s) is then reduced, for example, by forming, so that after joining the two components, the overlapping edge area essentially regains the thickness the components had before forming. The components are then interlocked in the edge areas to be defined and joined by forming in such a way that the joined sheet has a roughly uniform thickness. This creates a positive-locking and/or force-locking, but preferably reversible, connection between the surface structures of the edge areas of the two components. The material thickness within the joining zone should largely correspond to the initial sheet thicknesses of the joining partners and exhibit no thickening or overlapping. The joint is built up in two process steps to achieve this:

• • The first step is the preparation of the edge areas of the joining partners, preferably through a forming process. For example, sheet metal forming by rolling or incremental forging can reduce the thickness of the edge areas and introduce surface structures into the edge areas of the joining partners. This is generally done symmetrically on both joining partners.
• • In the second step, the joining partners are positioned relative to each other so that the surface structures of the edge areas align perfectly. This is followed by a second forming step that joins the two edge areas together using the surface structures, either through a form-fit and/or force-fit connection. This can be achieved through a rolling process or incremental forming with linear tool movement.

This creates a close, yet advantageously detachable, connection between the overlapping edges of the joining partners. Furthermore, this connection can be designed with respect to the geometry and thickness of the joining partners so that it is equal to, or only slightly thicker than, the thickness of the joining partners before joining. This allows for virtually seamless transitions between joining partners, even those made of different materials, which is particularly advantageous in automotive body construction.

It is advantageous if the surface structures of the edge regions of the two joining partners are preferably designed to be prismatically interlocked and/or to have undercuts, and thus interlock appropriately. For example, if prismatically shaped projections extending from the edge region are provided on one joining partner and incorporated into the edge region... If the surfaces of the joining partners have corresponding recesses, these prismatic projections and recesses can be joined force-fitted perpendicular to the plane of the edge region. Simultaneously, the projections and recesses interlock in a form-fit manner parallel to the plane of the edge region, thus enabling a high load-bearing capacity of the connection parallel to the plane of the edge region. Therefore, the connection between the joining partners can be designed to withstand the load by using the highly variable shapes of the matching surface structures of the edge regions. At the same time, it is also possible, for example during recycling of the joining partners, to relatively easily disassemble the connection by subjecting it to a load along the force-fit direction in such a way that the force-fit connection separates and the joining partners can be separated. This greatly simplifies the separation of materials by type.

It is advantageous if the connection between the joining partners is designed in such a way that, depending on the main load on the connection, the surface structures of both partners are positively and/or force-fitted. This can be achieved through the shape and arrangement of the surface structures, such as linear structures like grooves or point structures like local protrusions and depressions. There are no limits to the variation and combination of such surface structures. In particular, the design of the positive fit allows for many possibilities influencing the strength of the connection between the surface structures.

It is important that forming operations are performed during the joining of the edge surface structures. These operations lead to material displacements within the joining zone and preferably create multiple undercuts between the joined surface structures of the joining partners. In addition to simply compressing the surface structures of the two joining partners, for example by rolling, it is also possible to ensure that the surface structures of the joining partners interlock even more strongly after the actual joining process, thus increasing the strength of the connection. For example, it is conceivable that the forming operations specifically cause the material of the surface structures of one joining partner to flow into areas of the surface structures of the other joining partner, filling existing undercut areas and causing the surface structures to interlock intimately. For this purpose, protrusions of one joining partner can be deformed in such a way that they engage undercut areas of the surface structures of the other joining partner and interlock with them. It is conceivable that the forming operations for producing the undercuts are carried out by multi-stage and/or curved tool movements of forming tools, which move the material of the surface structures of one of the joining partners laterally to the plane of the edge area of the joining partner.

In a further embodiment, the introduction of the edge surface structures of the two joining partners and/or the joining of the edge surface structures of the two joining partners to each other can be carried out by bulk forming, in particular sheet metal bulk forming by rolling, or incremental forming, preferably forging with preferably linear tool movement. Such processes are easy to perform and can also be automated, so that a repeatable and therefore uniform forming of the surface structures is achieved. These forming processes can also be easily carried out in series production, preferably during the pressing of body parts in particular or in press brakes, thus allowing for high production volumes of the joint in a short time. However, it is also conceivable that the introduction of the edge surface structures of the two joining partners and/or the joining of the edge surface structures of the two joining partners to each other is carried out with the aid of joining tools, preferably in the form of robot-guided tools, or hand tools. This is useful for small series or individual workpieces, and possibly also for complex forming of surface structures that require certain kinematics of the movement of the forming tool.

Furthermore, it is conceivable that additional heat input can be achieved through induction, conduction, or laser-based heating of the edge regions to limit work hardening of at least one edge region by reducing its thickness. This allows for targeted control of the joining partners in their respective edge regions, which can be used to restore the strength of the joining partners in the edge regions after thickness reduction and forming to approximately or equal to their original strength.

It is particularly advantageous if the connection of the edge surface structures of the two joining partners is designed in such a way that the connection is in one direction, preferably the usual one. The connection acts as a positive-locking connection in one direction of loading, but as a force-locking connection in a separation direction. This effectively incorporates a coded strength distribution into the connection, which can be used at the end of the joining partners' service life for a simple and targeted separation of the joining partners. If the surface structures of the two joining partners are designed to be positive-locking in one loading direction, typically the main loading direction, but force-locking in a roughly perpendicular loading direction, the separation direction, then a controlled separation of the connection can be achieved by loading the connection in the perpendicular loading direction. This separation is simple to execute and allows for clean separation of the joining partners, thus enabling single-material recycling. By loading the force-locking connection with a separation force in the separation direction, the connection is then broken, enabling the single-material separation of the joining partners at the end of their service life. This can be achieved, for example, by tools that exert forces favorable for material separation on the friction-fit joining of the edge surface structures, preferably in effect of the separating force.

The invention further relates to a connection between joining partners, in particular between sheets, preferably made of different materials, with identically designed and interlocking surface structures for producing a form-fit and/or force-fit connection between the joining partners. The advantages and properties of such a connection have already been explained and described in detail in relation to the method according to the invention, so that full reference will be made here to that explanation.

The invention also relates to joining partners connected by means of a connection of joined edge-side surface structures according to claim 14.

• 1 - eine schematische Darstellung des grundsätzlichen Ablaufs des erfindungsgemäßen Verfahrens in Form eines Stadienplans über die Verformung des Randbereichs des ersten Fügepartners bis zur umformtechnischen Herstellung der kraftschlüssigen Verbindung mit dem zweiten Fügepartner,
• 2 - eine alternative Gestaltung einer kraftschlüssigen Verbindung gemäß 1,
• 3a, 3b - Darstellung von Möglichkeiten zur Auftrennung der kraftschlüssigen Verbindung gemäß 1 etwa zur Vorbereitung eines sortenreinen Recyclings,
• 4 - eine schematische Darstellung des grundsätzlichen Ablaufs des erfindungsgemäßen Verfahrens in Form eines Stadienplans über die Verformung des Randbereichs des ersten Fügepartners bis zur umformtechnischen Herstellung der formschlüssigen Verbindung mit dem zweiten Fügepartner,
• 5 - eine alternative Gestaltung einer mehrfach formschlüssigen Verbindung gemäß 4.

They show:

• 1 - a schematic representation of the basic process of the inventive method in the form of a stage plan from the deformation of the edge region of the first joining partner to the forming-technical production of the force-fit connection with the second joining partner,
• 2 - an alternative design of a force-fit connection according to 1 ,
• 3a , 3b - Presentation of possibilities for separating the force-fit connection according to 1 for example, to prepare for single-stream recycling,
• 4 - a schematic representation of the basic process of the inventive method in the form of a stage plan from the deformation of the edge area of the first joining partner to the forming-technical production of the positive-locking connection with the second joining partner,
• 5 - an alternative design of a multi-way positive locking connection according to 4 .

In the 1 A schematic representation of the basic process of the inventive method is shown in the form of a stage plan, depicting the deformation of the edge region of the first joining partner 2 up to the forming process that creates the force-fit connection 1 with the second joining partner 3. The joining partner 2, shown only in the edge region to be joined (here a sheet 2), is formed according to the 1a to 1d between an upper punch 4 and a counter-holder 5, deformed by a compressive force 6, wherein surface structures 8, 9 in the form of a projection 8 and a recess 9 are incorporated into the upper punch 4, which are pressed into the edge region of the joining partner 2 and result in a correspondingly stepped shape of the edge region of the joining partner 2, as shown in the 1c more precisely, the edge region of the joining partner 2 is also reduced in thickness by the flattening area 21 of the upper punch 4 and flows into the area below the upper punch 4, forming a region 7 of reduced thickness after forming. The upper punch 4 and counter-holder 5 can exert a linear force 6 on the edge region of the joining partner 2, but it is also conceivable to design the upper punch 4 and counter-holder 5 in the form of rollers 13, between which the edge region of the joining partner 2 is guided.

Not shown, but analogously, joining partner 3 is reshaped in its corresponding edge region so that it also exhibits complementary shapes matching the surface structures 8, 9 of joining partner 2. As in the 1e to 1h As can be seen, the edge regions of the joining partners 2, 3 are placed on top of each other in the intended manner, and the corresponding surface structures 8, 9 of the joining partners 2, 3 are arranged appropriately to each other. By applying a compressive force 6 from a suitably shaped upper punch 4 and counter-holder 5, the sections of the joining partners 2, 3 to be deformed are pressed together due to the shape of the upper punch 4 and counter-holder 5, forming a force-fit connection between the joining partners 2, 3. For this purpose, the surface structures 8, 9 align themselves in the form of a projection 8 and The first joining partner 2 is recessed into the respective counter-form 9, 8 of the second joining partner 3 and are pressed together by the forming force 6. This creates an intimate connection between these surface structures 8, 9 of the joining partners 2, 3, which acts as a frictional connection in the direction of the force 6. If, however, the connection 1 thus formed is subjected to a tensile load in the direction of the sheet plane of the joining partners 2, 3, the surface structures 8, 9 of the joining partners 2, 3 act as a positive-locking connection, resulting in a significantly higher load-bearing capacity of the connection 1 in this direction than in the direction of the force 6. The joined state of the connection 1 after the second forming operation is described in the 1g and 1 hour better to recognize. According to 1i This forming process for joining the joining partners 2, 3 can also be carried out using rollers 13, wherein the rollers 13 corresponding to the upper die 4 and the counter-holder 5 can have chamfers 11 machined in a corresponding manner. These chamfers serve not only to press the flattened end region 7 of the edge regions of the joining partners 2, 3 and to insert these end regions 7 into the recesses 12, thus allowing for a largely smooth design of the joint area 1. The joint area 1 is only slightly thicker than the initial thickness of the joining partners 2, 3, which can be particularly advantageous in visible areas of the joining partners 2, 3, which are formed as sheet metal, for example on a car body.

The reduction in sheet thickness introduced during the first process step of edge preparation in area 7, which, even after the joining step, appears to have a negative impact on the load-bearing capacity of the joint 1, especially under longitudinal loads, due to smaller stress-carrying cross-sections compared to the original material of the joining partners 2, 3, is compensated for by the work hardening caused by the bulk forming operations of the two process steps. This increase in strength results in a joint 1 with equivalent strength, and at least 70% to even over 100% of the original load-bearing capacity of the joining partners 2, 3 can be achieved. It is also conceivable to selectively influence the work hardening by heating the sheet in area 7.

In the 2 is in to 1 Correspondingly, a different design of the connection 1 can be identified, in which the shaping of the upper punch 4 and counter-holder 5 with projections 14 creates a groove-like clamping action 15 between the joining partners 2, 3. Again, the thickness of the first joining partner 2 is reduced and stretched by the front flattened area 21, with the surface structures 8, 9 in the form of a projection 8 and a recess 9 being introduced by the upper punch 4 under the force 6. The joining partner 2 is then inserted with the correspondingly oppositely shaped joining partner 3 between other upper punches 4 and counter-holders 5, each with projections 14, the projections 14 forming the areas 7 of reduced thickness of the joining partners 2, 3 into a groove-like shape and inserting them into the recesses 8 of the respective other joining partner 3, 2, as shown in 2g and 2h which is easier to see. Here again, a force-fit connection 1 exists between the joining partners 2, 3 in the direction of force 6. However, if the connection 1 is loaded in the direction of the sheet plane of the joining partners 2, 3, i.e., under tension, the surface structures 8, 9 of the joining partners 2, 3 act in a form-fit manner with each other. According to 2i This forming process can also be used to join the joining partners 2, 3 by means of rollers 13.

In the 3 The example of connection 1 shows the joining partners 2, 3 according to 1 The illustration shows how the bond 1 can be broken down again, for example, for the single-stream recycling of the quite different materials of the joining partners 2 and 3. In the 3a It can be seen that the joining partners 2, 3 are clamped on their upper and lower sides by means of clamping devices 16 and held outside the area of the connection 1. By pivoting, for example, the right clamping devices 16, which engage the joining partner 3, about a pivot direction 17, the frictionally interlocked surface structures 8, 9 of the joining partner 3 are levered out of the surface structures 8, 9 of the other joining partner 2 and the connection 1 is thereby released.

In the 3b Another approach to breaking connection 1 can be identified. This approach takes advantage of the fact that the connection 1 between joining partners 2 and 3 is frictionally locked in the direction of force 6 and can withstand significantly lower loads than in the direction of the sheet plane of joining partners 2 and 3. By means of separating punches 22, which are dimensioned and arranged to match the recesses 8 and the projections 9, the frictionally locked connection between the surface structures 8 and 9 of joining partners 2 and 3 can be broken under the influence of forming forces 6, and connection 1 can be completely removed. Figuratively speaking, the separating punches 22 push the surface structures 8 and 9 of joining partner 3 out of the surface structures 8 and 9 of joining partner 2, so that joining partners 1 and 2 can be separated from each other.

After joining according to the type of connection 1 Tests were carried out on a universal testing machine. Firstly, the sample was subjected to stress in the sheet metal direction. The test specimen demonstrated a load-bearing capacity exceeding 5000 N. A second specimen, using the same joining strategy and material, was subjected to a shear force and a bending load in a three-point bending test. In this test, the joint failed at a load of only 200 N. The targeted application of loads thus enables the separation of joint 1, while good strength values can be achieved under other loads. This indicates a bond with a coded connection. Therefore, joint 1 allows for its separation under a specific load direction. This is highly advantageous for the application of R-methods to multi-material joints, enabling separation of the individual material types.

In the 4 and 5 Variations of the connection 1 between joining partners 2 and 3 can be identified, each of which also exhibits positive-locking elements acting in the direction of force 6. Regarding the basic procedure for producing connection 1, reference is made to the preceding explanations, and only the differences are discussed here.

The joining partners 2 and 3 exhibit a positive fit due to the design of the undercut 19. The elasticity of the sheet metal material and springback effects that occur during the joining process result in a superimposed force-fit connection. Preparation requires forming operations that create an undercut 19 and thus enable the positive fit, as described below. This can be achieved through a multi-stage or curved movement of the forming tools 4, 5, and 13.

Reinforced undercuts with improved interlocking are also conceivable. Connection 1 also requires the aforementioned two-stage procedure; however, the second joining step necessitates more complex forming operations that lead to material displacements within the joining zone, creating multiple undercuts 19 and thus producing a higher-quality and stronger connection 1.

To create a positive-locking connection 1 also in the direction of force 6, in the 4 the lead of 9, which is in the 4a to 4c is produced in a manner known per se, according to 4e its height is reduced, with the flow of the material of the projection 9 as in the 4f The joining process is indicated laterally and forms a kind of nose as an undercut 19 on the upper side of the reduced-thickness projection 9. This undercut 19 can now be used during joining with the joining partner 3 according to 4g The inclined surface 11 of the upper die 4 is used to deform the area 7 of reduced thickness of the other joining partner 3 such that a section encompasses the undercut 19 and clamps itself to this undercut 19. This is also done symmetrically at the other end of the joining partner 2, as shown in the 4h and 4 years to recognize. This forming process can in turn be carried out using rollers 13, which have the corresponding inclined surfaces 11.

In the execution of the joining partners 2, 3 according to 5 An undercut 19 is also created at the joining partners 2, 3 by means of projections 14 that cause the material of the joining partners 2, 3 to flow laterally, and the end regions of the thinner area 7 of the other joining partner 3 are pressed into these recesses 20. An advantage of this design is that the thickness of the joining partners 2, 3 after the connection 1 is made is identical to the thickness of the joining partners 2, 3 before the connection is made, and thus the joining partners 2, 3 transition smoothly into one another, except for small grooves. This ensures that the sheet metal plane has no geometric discontinuity, which is particularly important for the outer skin contours of car bodies, as a largely smooth surface can be produced.

Part number list

1

Connection

2

Joining partner

3

Joining partner

4

Rubber stamp

5

Counterweight

6

Deformation direction

7

Low thickness area

8

Surface structure protrusion

9

Surface structure depression

10

bevel

11

slanted section stamp

12

in-depth

13

roller

14

projection

15

groove-like depression

16

Clamping device

17

direction of rotation

18

Slant

19

Undercut

20

Recessed undercut

21

flattening area

22

Separating stamp

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• JP 04 182 007 A [0008]
• US 3131471 [0010]

Cited non-patent literature

• https://www.ibf.rwth-aachen.de/cms/ IBF/Research/Cross-cutting topics/-peqi/Materials-connect/ [0009]

Claims (22)

A method for producing a connection between joining partners (2, 3), in particular between sheets, made of preferably different materials, in which a form-fitting and/or force-fitting connection between the joining partners (2, 3) is produced by means of identically designed and interlocked surface structures (8, 9), characterized in that the identically designed and interlocking surface structures (8, 9) of the joining partners (2, 3) are arranged at the edge in at least one edge region each, overlapping each other in the position to be joined of the joining partners (2, 3), wherein at least the edge region of the first joining partner (2) is deformed by forming technology such that the thickness dimensions in this edge region are reduced and the surface structures (8, 9) are introduced into the thickness-reduced edge region (7), the surface structures (8, 9) matching the surface structures (8, 9) of the edge region of the first joining partner (2) in the The edge region of the second joining partner (3), preferably with a reduction of the thickness dimensions also in this edge region, is introduced, the first and second joining partners (2, 3) are positioned in such a section-wise overlapping manner that the corresponding surface structures (8, 9) of the edge regions of the two joining partners (2, 3) are aligned with each other, and these edge regions with the surface structures (8, 9) are joined together by forming technology. Procedure according to Claim 1 , characterized in that the reduction of the thickness dimensions of the at least one joining partner (2, 3) is carried out in such a way that, after joining the joining partners (2, 3) in the joined edge area, the thickness of the joined joining partners (2, 3) is equal to or only slightly greater than the undeformed thickness of one or both joining partners (2, 3). Procedure according to one of the Claims 1 or 2 , characterized in that the surface structures (8, 9) of the edge regions of the two joining partners (2, 3) are preferably prismatically designed to be joined into one another and/or to have undercuts (19) and interlock appropriately. Procedure according to Claim 3 , characterized in that the surface structures (8, 9) of the two joining partners (2, 3) are connected to each other in a form-fitting and/or force-fitting manner. Method according to one of the preceding claims, characterized in that forming operations are carried out during the production of the connection of the edge-side surface structures (8, 9) which lead to material displacements within the joining zone and preferably generate several undercuts (19) between the connected surface structures (8, 9) of the joining partners (2, 3). Procedure according to Claim 5 , characterized in that the forming operations for producing the undercuts (19) are carried out by multi-stage and/or curved tool movements of forming tools (4, 5, 13). Method according to one of the preceding claims, characterized in that the introduction of the edge-side surface structures (8, 9) of the two joining partners (2, 3) and/or the joining of the edge-side surface structures (8, 9) of the two joining partners (2, 3) to each other is carried out by bulk forming, in particular sheet metal bulk forming by means of rolling, or incremental forming, preferably forging with preferably linear tool movement. Procedure according to Claim 7 , characterized in that the introduction of the edge-side surface structures (8, 9) of the two joining partners (2, 3) and/or the joining of the edge-side surface structures (8, 9) of the two joining partners (2, 3) is carried out in series processes, preferably during the pressing of body parts in particular or in press brakes. Procedure according to Claim 7 , characterized in that the introduction of the edge-side surface structures (8, 9) of the two joining partners (2, 3) and/or the joining of the edge-side surface structures (8, 9) of the two joining partners (2, 3) to each other is carried out using joining tools (4, 5, 13), preferably in the form of robot-guided tools (4, 5, 13), or hand tools (4, 5, 13). Method according to one of the preceding claims, characterized in that additional heat is introduced by induction-, conduction- or laser-based heating of the edge regions in order to limit the work hardening of the at least one edge region by reducing its thickness dimensions. Method according to one of the preceding claims, characterized in that the connection of the edge-side surface structures (8, 9) of the two joining partners (2, 3) is formed such that the connection is in one direction, before in the usual direction of load on the connection, it acts as a form-fit connection, but in a separation direction it acts as a force-fit connection. Procedure according to Claim 11 , characterized in that the application of a separating force to the force-fit connection in the separation direction causes the connection (1) to separate and enables a sort-pure separation of the joining partners (2, 3) at the end of the life cycle of the joining partners (2, 3). Procedure according to one of the Claims 11 or 12 , characterized in that the separation of the force-fit connection is achieved by tools (4, 5) which exert forces (6) favorable for material separation on the force-fit joining connection (1) of the edge surface structures (8, 9), preferably in effect of the separation force. Connection (1) between joining partners (2, 3), in particular between sheets, preferably made of different materials, with identically designed and interlocking surface structures (8, 9) for producing a form-fit and/or force-fit connection between the joining partners (2, 3), characterized in that the identically designed and interlocking surface structures (8, 9) of the joining partners (2, 3) are arranged at least at their edges in an overlapping edge region in the joining partner (2, 3) position, wherein a forming process reduces the thickness dimensions of at least the edge region of the first joining partner (2) and introduces the surface structures (8, 9) into the thickness-reduced edge region (7), and a forming process introduces the surface structures (8, 9) matching the surface structures (8, 9) of the edge region of the first joining partner (2) into the edge region of the second joining partner. (3), preferably reducing the thickness dimensions also in this edge region, introduces the first and second joining partners (2, 3) so that they overlap each other section by section with the surface structures (8, 9) of the edge regions of the two joining partners (2, 3) fitting to each other, and a forming process joins these edge regions with the surface structures (8, 9) together by forming technology. Connection (1) according to Claim 14 , characterized in that the thickness of the joined partners (2, 3) in the overlapping edge area is equal to or only slightly greater than the undeformed thickness of one or both of the joined partners (2, 3). Connection (1) according to one of the Claims 14 or 15 , characterized in that the surface structures (8, 9) of the edge regions of the two joining partners (2, 3) are preferably prismatically interlockable and/or have undercuts (19). Connection (1) according to Claim 16 , characterized in that the surface structures (8, 9) of the two joining partners (2, 3) are positively and/or force-fit connected to each other after the joining forming process. Connection (1) according to Claim 14 , characterized in that the form-fitting surface structures (8, 9) of the two joining partners (2, 3) have matching undercuts (19). Connection (1) according to one of the Claims 14 until 18 , characterized in that the edge regions of the two joining partners (2, 3) can be heated before and/or during and/or after the joining forming process in order to reduce or eliminate cold working of the edge regions. Connection (1) according to one of the Claims 14 until 19 , characterized in that the connection of the edge-side surface structures (8, 9) of the two joining partners (2, 3) is designed such that the connection (1) acts as a form-fit connection (1) in one direction, preferably the usual loading direction of the connection (1), but is force-fit in a separation direction. Connection (1) according to Claim 20 , characterized in that a separating force (6) in the separating direction causes the force-fit connection (1) to separate and enables a sort-pure separation of the joining partners (2, 3) at the end of the life cycle of the joining partners (2, 3). Joining partners (2, 3) connected by means of a connection of joined edge-side surface structures (8, 9) according to Claim 14 .