DE102019130786A1 - Process arrangement as well as auxiliary joining element for such a process arrangement - Google Patents

Abstract

The invention relates to a process arrangement for the production of a component connection with an auxiliary joining element (5), which has an element head (11) and an element shaft (9), the auxiliary joining element (5) with its element shaft (9) below in a setting step (I) Maintaining a remaining base thickness (r) can be driven into at least one first component (1), and in a welding step (II) the element head (11) of the auxiliary joining element (5) driven into the first component (1) with the second component (3) Resistance spot welding can be welded, namely with the formation of a weld nugget (13) between the auxiliary joining element (5) and the second component (3). According to the invention, the top of the head of the auxiliary joining element (5) facing the second component (3) has at least one ring contour (21, 23) surrounding a longitudinal axis (L) of the auxiliary joining element.

Description

The invention relates to a process arrangement for producing a component connection with the aid of an auxiliary joining element according to the preamble of claim 1, such an auxiliary joining element according to claim 9 and a method for producing the joining element according to claim 10.

The production of a mixed connection from, for example, an aluminum sheet metal part and a steel sheet metal part can take place in a joining process in which the auxiliary joining element is punched into the aluminum sheet metal part in a setting process step. In a subsequent welding process step, the auxiliary joining element is connected to the steel sheet metal part by resistance spot welding (direct, accessible from both sides).

Such a generic joining method is from DE 10 2014 011 599 A1 known. Accordingly, the auxiliary joining element has an element head and an element shaft. In the setting process step, the auxiliary joining element is driven into a first component (aluminum sheet metal part) with its element shaft while maintaining a residual base thickness. In the subsequent welding step, the element head of the auxiliary joining element driven into the first component is welded to the second component (sheet steel part) by resistance spot welding, with the formation of a weld nugget between the auxiliary joining element and the second component.

The implementation of the above joining process is particularly problematic for low-strength, thin and galvanized sheet steel parts, due to the high conductivity on the sheet surface (especially due to the galvanization). In the joining process, there is therefore the problem that there is no longer enough heat available for the formation of a sufficiently large weld nugget, which can result in only an inadequate connection characteristic.

From the DE 10 2010 046 318 A1 a joining element for joining at least two parts to be joined together is known. From the DE 10 2017 115 529 A1 a welding auxiliary joining part is known. From the EP 2 762 731 A1 a method for connecting two components with the aid of an auxiliary joining element is known. From the DE 10 2012 104 364 A1 a weld rivet for a welded connection is known. From the DE 197 40 022 A1 a contact piece and a method for fastening it to a carrier are known. From the US 5,671,521 A1 a method for resistance spot welding with the aid of an auxiliary joining element is known. From the EP 0 088 231 A1 an electrical resistance pressure welding process is known. From the US 6,373,021 B1 Another resistance spot welding method is known. From the DE 10 2012 013 589 A1 a self-punching joining element for a resistance element welding process is known. From the DE 10 2012 013 325 A1 a method for joining components with the aid of a joining aid is known.

The object of the invention is to provide a process arrangement for producing a component connection with the aid of an auxiliary joining element, with which, compared to the prior art, a component connection with a flawless connection characteristic can be provided.

The object is achieved by the features of claim 1, claim 9 or claim 10. Preferred developments of the invention are disclosed in the subclaims.

According to the characterizing part of claim 1, the upper side of the head of the auxiliary joining element facing the second component has at least one ring contour encircling an auxiliary joining element longitudinal axis. The ring contour protrudes from a head base area by a ring contour height. In preparation for the welding step, the second component is placed on the ring contour of the auxiliary joining element, with the formation of an annular contact surface between the element head and the second component. In this way, the contact area between the element head and the second component is reduced, in comparison to a planar top face of the head which is in contact with the second component over a large area. In the welding step, the current density and thus the heat available for the formation of the weld nugget is increased. Therefore, compared to the prior art, with otherwise the same process parameters, a significantly larger weld nugget with a correspondingly improved connection characteristic results.

The processing (molding, turning or milling) of the element head geometry with circular ring contours results in an increase in current density, which significantly improves the process reliability of the welding process. The resulting current concentration increases the local energy input and contributes to the formation of a correspondingly large weld nugget even at lower welding currents. The associated increase in the current density between steel elements and sheet metal results in the same starting conditions for all surface variants and, due to the increased current density, lower welding currents or shorter welding times can be used.

With the invention, a rapid, uniform generation of heat is independent of the surface coating, sheet thickness and Material alloy guaranteed. In addition, there is an increase in the local current density at the contact point and thus a reduction in the welding currents used or shorter welding times (this results in further economic advantages in system operation). Furthermore, the process reliability is increased. In addition, the lower heat / energy input enables it to be used for one-sided indirect spot welding and / or the joining of profiles (e.g. joint points) without causing too large a bulge.

In a technical implementation, the head base area of the element head of the auxiliary joining element can be designed to be planar. The auxiliary joining element can be designed to be rotationally symmetrical about the longitudinal axis of the auxiliary joining element.

In a first embodiment variant, the ring contour can have a radially inner contour flank and a radially outer contour flank in cross section. The two contour flanks can run in a straight line and converge at an acute-angled apex edge. As an alternative to this, the two contour flanks can each merge at a radially outer transition edge and at a radially inner transition edge into an apex surface that is plane-parallel to the head base surface. In a further embodiment variant, the two contour flanks (slightly curved) can converge at a ring contour apex, forming a semicircular or dome-shaped ring contour cross section.

The head diameter of the element head can, for example, be 1.25 to 1.5 times larger than an element shaft outer diameter. This results in a head edge that projects radially outward from the element shaft. In addition, several, in particular exactly two, ring contours can be provided which are aligned concentrically to one another and delimit at least one circumferential groove between them.

The number of ring contours can be between 1 and 5, whereby the ring contours can be evenly distributed over the element head. The ring contour height should preferably be chosen between 0.1 and 0.5 mm. The ring contour can be pointed, semicircular or flat.

With regard to a perfect design of a weld nugget, it is preferred if the, in particular radially outer, ring contour lies on a ring contour diameter that is smaller than or equal to the element shaft outer diameter.

The auxiliary joining element according to the invention is to be designed with regard to the material, the geometry, the coating, the strength and / or the die used in the setting step (punching process). A cold heading or cold extrusion steel can preferably be used as the material of the auxiliary joining element. This ensures an economically favorable production through a possible cold impact process. In addition, the material can have a significantly lower carbon content than a rivet material used in commercially available semi-tubular rivet elements. The material used must also be suitable for welding. The following materials are suitable as examples: 17MnB4, 19MnB4, 20MnB4, 27MnB4. By means of such materials, the deformation behavior of the joining element can be improved and cracks in the element can be avoided. The material strength of the auxiliary joining element should be adapted to the application and the materials and can, for example, preferably be between 950 and 1100 N / mm ² , so that the auxiliary joining element can cut into the aluminum material of the first component in the setting step and at the same time is still sufficiently ductile for deformation in the aluminum material is.

The auxiliary joining element can be produced in a process sequence in which an auxiliary joining element blank is first produced in a cold forming step. The joining element blank is remunerated in a remuneration step. This is followed by a coating step in which the auxiliary joining element blank is coated with an anti-corrosion layer, to be precise with the completion of the auxiliary joining element.

In a first variant, the ring contour can be formed directly in the cold forming step, for example by cold hammering or by turning, depending on the number of elements. The advantage of this variant is that the auxiliary joining element is not yet tempered and coated, so that no defects are to be expected on the element head. For the element setting process, a corresponding negative form must be incorporated in the setting die in order to avoid element damage during the setting process step.

Alternatively, the ring contour can be formed directly in the setting step. In this case, the setting step has a shaping effect on the element head (that is, the ring contour is shaped in the setting step). For this purpose, the setting punch must have a corresponding negative shape of the ring contour on its punch surface facing the auxiliary joining element. In this variant, the auxiliary joining element can be produced and coated in a conventional manner. The ring contour geometry in the set state is, however, subject to corresponding fluctuations and can possibly lead to deviating welding results.

In a preferred embodiment, the material thickness of the element head compared to the Be increased material thickness on the element shaft wall, namely with the formation of a material thickening. The material thickening provides welding material for the weld nugget between the element head and the second component. The element head material thickness can preferably be between 1 and 1.5 mm (measured on the longitudinal axis of the auxiliary joining element). The head diameter of the element head can be between 5 and 7 mm. The outer shaft diameter can be between 3.0 and 6.5 mm, while the length of the auxiliary joining element can be between 2.0 and 4.0 mm.

After the setting step has taken place, the element head of the auxiliary joining element driven into the first component can protrude from the surface of the first component with a head overhang. The head overhang can preferably be between 0.1 and 0.5 mm.

In the setting step, the circumferential element shaft wall can be expanded radially outward by an expansion path at right angles to the setting direction. This creates an undercut. The expansion path can be 0.1 mm or greater, for example.

An exemplary embodiment of the invention is described below with reference to the accompanying figures.

• 1 ein Querschliffbild einer fertiggestellten Bauteilverbindung;
• 2 in einer teilweisen Seitenschnittdarstellung unverformtes Fügehilfselement in Alleinstellung;
• 3 und 4 unterschiedliche Ansichten auf das Fügehilfselement;
• 5 und 6 jeweils Ansichten, die die Prozessschritte zur Herstellung der in der 1 gezeigten Bauteilverbindung veranschaulichen;
• 7 und 8 jeweils Ringkonturen gemäß weiterer Ausführungsbeispiele.

Show it:

• 1 a cross-section of a completed component connection;
• 2 in a partial side section view, undeformed joining auxiliary element on its own;
• 3 and 4th different views of the auxiliary joining element;
• 5 and 6th each views showing the process steps for producing the in the 1 illustrate component connection shown;
• 7th and 8th each ring contours according to further exemplary embodiments.

In the 1 a completed component connection is shown in which an aluminum sheet metal part 1 as a first joining partner with a steel sheet metal part 3 is connected as a second joining partner. The two joining partners 1 , 3 are via an auxiliary joining element 5 connected with each other. The above material pairing is purely exemplary. As an alternative to this, any other materials are also conceivable, for example magnesium, possibly also plastics.

The auxiliary joining element 5 is according to the figures with a hollow element shaft 9 as well as an element head 11 educated. In the 1 is elementalism 9 while maintaining a residual bottom thickness r in a later-described setting step I in the material of the aluminum sheet metal part 1 (first joining partner) stamped. The element head 11 of the auxiliary joining element 5 is with the second component (sheet steel part 3 ) with the formation of a weld nugget 13th welded.

In the 2 is the auxiliary joining element 5 shown undeformed in a unique position. As a result, the joining element is 5 around a longitudinal axis L. rotationally symmetrical, with one wall 15th of the hollow cylindrical element shaft 9 a dome-shaped cavity that is open at the bottom 17th limited. This is in the axial direction with a material depth t in the element shaft 9 incorporated. The elemental wall 15th has a material thickness ms that is in the 2 is dimensioned much smaller than the element head material thickness m _K extending along the longitudinal axis L. results. This is how the element head is 11 with an additional material thickening 21 formed which has a sufficiently large amount of weld material for the formation of the weld nugget 13th provides. The thickening of the material 21 is dimensioned so that after welding step II ( 6th ) in the element header 11 a sufficiently large material thickness Δm ( 1 ) remains without structural change.

In the 2 and 4th is the head diameter d _K for example 5.5 mm, while the outer shaft diameter ds is 3.35 mm. In this way there is one of the elemental community 9 head edge protruding radially outwards 10 . The two ring contours 21 , 23 are therefore radially inside the circumferential head edge 10 positioned. The length I of the auxiliary joining element 5 lies in the 2 at 2 , 8th mm, with a head side height I _K is about 0.3 mm.

As from the 2 further emerges, has the auxiliary joining element 5 at his the element head 11 remote side at the element base a circumferential base edge 19th on. In setting step I, this has the effect of deforming the auxiliary joining element at an early stage 5 opposite. At the same time there is a spreading out of the elements 9 by a given spread Δy ( 1 ) controlled radially outwards.

In the 2 has the auxiliary joining element 5 on his, the second component 3 facing top of the head two around the longitudinal axis of the auxiliary joining element L. circumferential ring contours 21 , 23 on. Any ring contour 21 , 23 protrudes by a ring contour height H ( 3 ) from a head base 25th from. The base of the head 25th is in the 2 and 3 formed flat. Any ring contour 21 , 23 has a radially inner contour flank in cross section 27 and a radially outer contour flank 29 on. The two contour flanks 27 and 29 run in the 3 straight forward and go to the upper transition edges 31 in one to the head base 25th plane-parallel apex 33 above.

In the 2 is an outside diameter d _R the radially outer ring contour 21 dimensioned slightly smaller than the element shaft outer diameter ds.

Based on 5 and 6th is a joining process for the production of the 1 Component connection shown illustrated. As a result, the auxiliary joining element 5 first in one setting direction with the help of a setting punch 35 into that on a die 28 positioned first component 1 punched in, while maintaining the remaining bottom thickness r. After setting step I, the element head protrudes 11 of the auxiliary joining element 5 with a head overhang u from the surface of the first component 1 before, which is, for example, 0.3 mm and is roughly the same size as the head side height I _K ( 2 ).

To prepare for welding step II ( 6th ) the second component 3 on the two joining element ring contours 21 , 23 placed, namely with the formation of two (mutually concentric) annular contact surfaces between the element head 11 and the second component 3 as well as forming a free space a ( 6th ) between the base of the head 25th and the component 3 . Then the two opposing electrodes 37 with the interposition of the two components 1 , 3 as well as the auxiliary joining element 5 moved together, the auxiliary joining element 5 in alignment with the two electrodes 37 is aligned and a spot weld is performed to form the nugget 13th between the element head 11 and the second joining partner 3 .

By means of the two ring contours 21 , 23 In welding step II, the current density at the ring-shaped contact surfaces and thus that for the formation of the weld nugget 13th available heat significantly increased.

In the 7th and 8th further element head geometries are indicated. According to the 7th are a radially inner ring contour 23 and a radially outer ring contour 21 educated. On every ring contour 21 , 23 the two contour flanks run 27 , 29 straight on an acute-angled apex edge 39 together. In the 8th are the two contour flanks 27 , 29 slightly curved and run in the shape of a dome at a ring contour apex 41 together.

List of reference symbols

1

Aluminum sheet metal part

3

Sheet steel part

5

Auxiliary joining element

9

hollow element shaft

10

Head edge

11

Element head

13th

Weld nugget

15th

Element shaft wall

17th

Element shaft cavity

19th

Foot edge

21

Thickening of the material

21, 23

Ring contours

25th

Head base

27

radially inner contour flank

28

die

29

radially outer contour flank

31

Transition edge

33

Vertex surface

35

Setting punch

36

negative form

37

Electrodes

39

acute-angled apex edge

41

Vertex

L.

Longitudinal axis

a

free space

Δm

Material thickness without structural change

dK

Head diameter

dS

Outer shaft diameter

dR

Ring contour outer diameter

l

Joining element length

IK

Head-to-side height

Δy

Spreading path

H

Ring contour height

u

Head overhang

mK

Material thickness along the longitudinal axis L.

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

• DE 102014011599 A1 [0003]
• DE 102010046318 A1 [0005]
• DE 102017115529 A1 [0005]
• EP 2762731 A1 [0005]
• DE 102012104364 A1 [0005]
• DE 19740022 A1 [0005]
• US 5671521 A1 [0005]
• EP 0088231 A1 [0005]
• US 6373021 B1 [0005]
• DE 102012013589 A1 [0005]
• DE 102012013325 A1 [0005]

Claims (10)

Process arrangement for the production of a component connection with an auxiliary joining element (5) which has an element head (11) and an element shaft (9), the auxiliary joining element (5) in a setting step (I) with its element shaft (9) while maintaining a residual base thickness ( r) can be driven into at least one first component (1), and in a welding step (II) the element head (11) of the auxiliary joining element (5) driven into the first component (1) can be welded to the second component (3) by resistance spot welding, namely with the formation of a weld nugget (13) between the auxiliary joining element (5) and the second component (3), characterized in that the upper side of the head of the auxiliary joining element (5) facing the second component (3) has at least one longitudinal axis around an auxiliary joining element (L) has circumferential ring contour (21, 23) which protrudes by a ring contour height (h) from a head base surface (25), and that in preparation for the welding step (II) the second component l (3) can be placed on the auxiliary joining element ring contour (21, 23), namely with the formation of an annular contact surface, whereby the current density and thus the heat available for the formation of the weld nugget (13) is increased in the welding step (II). Process arrangement according to Claim 1 , characterized in that the head base surface (25) of the element head (11) is planar, and / or the auxiliary joining element (5) is designed to be rotationally symmetrical about the longitudinal axis (L) of the auxiliary joining element. Process arrangement according to Claim 1 or 2 , characterized in that the ring contour (21, 23) has a radially inner contour flank (27) and a radially outer contour flank (29) in cross section, and that in particular the two contour flanks (27, 29) are straight and / or at an acute angle The apex edge (39) converge to form a triangular ring contour cross-section, or that the two contour flanks (27, 29) each at a radially outer transition edge (31) and a radially inner transition edge (31) into one to form a trapezoidal ring contour cross section Head base surface (25) pass over plane-parallel apex surface (33), and / or that the contour flanks (27, 29) converge at an annular contour apex (41) to form a dome-shaped annular contour cross section. Process arrangement according to one of the preceding claims, characterized in that the head diameter (d _K ) of the element head (11), in particular 1.25 to 1.5 times, is greater than the element shaft outer diameter (ds), namely with the formation of a head edge (10) projecting radially outward from the element shaft (9). Process arrangement according to one of the preceding claims, characterized in that at least, in particular precisely, two ring contours (21, 23) are provided which are aligned concentrically to one another, and that in particular between the inner flank (27) of the radially outer ring contour (21) and the A circumferential groove (30) is delimited on the outer flank (29) of the radially inner ring contour (23). Process arrangement according to one of the preceding claims, characterized in that a ring contour outer diameter of the, in particular radially outer, ring contour (21) is less than or equal to the element shaft outer diameter (ds), and / or that in particular the ring contour height (h) between 0.1 mm and 0.5 mm, in particular between 0.2 mm and 0.3 mm, and / or that the ring contour height (h) and the head-side height (I _K ) are approximately the same. Process arrangement according to one of the preceding claims, characterized in that the auxiliary joining element (5) can be produced in a process sequence in which an auxiliary joining element blank can be produced in a cold forming step, the auxiliary joining element blank can be tempered in a tempering step, and in a coating step the joining auxiliary element blank can be coated with a corrosion protection layer with completion of the joining auxiliary element (5). Process arrangement according to Claim 7 , characterized in that the ring contour (21, 23) can be shaped in the cold forming step, or that the ring contour (21, 23) can be shaped in the setting step (I), and / or that an auxiliary joining element (5) is inserted into the first Component (1) driving setting punch (35) has a negative shape (36) of the ring contour (21, 23) on its punch surface facing the joining auxiliary element (5). Auxiliary joining element for a process arrangement according to one of the preceding claims. Method for the production of an auxiliary joining element according to Claim 9 .

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