EP2704869A1

EP2704869A1 - Method and device for joining a composite sheet-metal part

Info

Publication number: EP2704869A1
Application number: EP12716014.1A
Authority: EP
Inventors: Azeddine Chergui; Robert Klimek
Original assignee: ThyssenKrupp Steel Europe AG
Current assignee: ThyssenKrupp Steel Europe AG
Priority date: 2011-05-04
Filing date: 2012-04-23
Publication date: 2014-03-12
Also published as: US20140224774A1; KR20140022419A; MX346909B; MX2013012824A; KR101920451B1; WO2012150144A1; DE102011100495A1; JP2014516793A; CN103534054A; CA2834744A1; DE102011100495B4; JP5810212B2

Abstract

The invention relates to a method for joining a composite sheet-metal part (2) with another component (3). The composite sheet-metal part (2) has at least two outer covering sheets (4, 5) and at least one nonmetal layer (6) arranged between the covering sheets (4, 5), and the other component (3) has at least one outer metal layer (4, 5). The composite sheet-metal part (2) and the other component (3) are brought between two electrodes (7, 8) of a resistance welding unit so as to overlap each other. The aim of the invention is to allow a joining of composite sheet-metal parts in a reliable manner by means of resistance welding. This is achieved in that an electrically conductive dummy element (11, 25, 27) is brought into contact with an outer covering sheet (4, 5), and at least one current path between the two electrodes (7, 8) is closed by the electrically conductive dummy element (11, 25, 27).

Description

METHOD AND DEVICE FOR ADDING A COMPONENT COMPONENT TO A FURTHER COMPONENT WITH A RESISTANT BELT UNIT

The invention relates to a method for joining a

Composite sheet metal part with another component, wherein the

Composite sheet metal part at least two outer cover plates and

5 at least one arranged between the cover plates

Has non-metallic layer and wherein the other

Component has at least one outer metallic layer, wherein the composite sheet metal part and the further component overlap each other between two electrodes

0 resistance welding unit are brought. Furthermore, the invention relates to a device for joining a

Composite sheet metal part with another component, wherein the

Composite sheet metal part at least two outer cover plates and at least one arranged between the cover plates

5 non-metallic layer and wherein the further

Component having at least one outer metallic layer, comprising a resistance welding unit comprising at least two electrodes. Composite sheet metal parts are composite materials, which are constructed in particular in the form of a sandwich. Composite sheet metal parts usually consist of two outer cover sheets and one

between the cover plates arranged plastic layer.

Due to the layer structure of the composite sheet metal parts, these 5 properties can be characterized by a component of a

unified or hardly achieved

could. For example, composite sheet metal parts can have very high local stiffnesses and strengths. In addition, composite sheet metal parts can have good sound insulating properties provide. Last but not least, composite sheet metal parts also allow a lower component weight, without sacrificing the other properties of the component. For this reason, composite sheet metal parts are increasingly being used as so-called lightweight sheets in motor vehicle construction.

The disadvantage here is that the composite sheet metal parts only partially for the widespread in motor vehicle

Resistance welding are suitable. Resistance welding, for example, is used to easily and inexpensively join the composite sheet metal parts to normal sheet metal parts. In resistance welding, there is a brief, high heat input into the composite sheet metal part, whereby the at least one between the cover plates

arranged non-metallic layer can be easily damaged. This is the case in particular with plastic layers, which have a lower temperature resistance and, in addition, a lower thermal conductivity than the outer cover plates. The plastic layers may also be electrically insulating or at least have a very low electrical conductivity.

The present invention is therefore based on the object, the method and the device in each case of the type mentioned above and described in more detail above

To design and develop that composite sheet metal parts can be reliably joined by resistance welding. This object is achieved according to claim 1 by a method of the type mentioned, in which an electric

conductive dummy element in contact with an outer cover plate

KJ / nb 110616 O April 23, 2012 is brought and in which at least one current path between the two electrodes via an electrically conductive

Dummy element is closed. The invention has therefore recognized that, in order to protect the composite sheet metal part during the joining at locally particularly stressed areas, a dummy element can be used, which is brought into contact with the composite sheet metal part. The dummy element is electrically conductive and preferably thermally stable. The dummy element may, for example, be very similar to the cover sheet in terms of these properties. If desired, the dummy element and the outer cover sheets may be made of the same or a similar material. However, it can also be provided that the dummy element has a much higher conductivity and / or considerably higher thermal stability. It may then be sufficient to improve the material quality of the dummy element instead of the outer cover plate. In resistance welding, at least two electrodes are positioned relative to the workpieces to be welded in such a way that between the electrodes an electrically conductive

Connection, a so-called current path is formed, which runs through at least one of the workpieces. The

Workpieces are in this case the composite sheet metal part and the other component. The electrodes may be designed differently and may be formed, for example, as part of a welding tongs or as roller electrodes. The dummy element is in at least one at

Resistance welding brought forming rung.

Ultimately, this causes the current path through the dummy element

KJ / nb 110616W0 April 23, 2012 closed, even if the current path with or without the

Dummy element can also be closed otherwise.

As a result, at least part of the current flows through the dummy element, whereby less heat is introduced into the composite sheet metal part. The dummy element can be a local

Thickening and thus greater sheet thickness of an outer

Simulate cover plate. The thickening in a locally narrow area is sufficient to prevent the heat input,

in particular in the non-metallic layer of

Composite sheet metal part to reduce, without affecting the actual joining of the workpieces.

In addition, the use of a dummy element avoids unnecessary material requirements. Namely, the dummy element is characterized by the fact that, preferably, for the mechanical and other properties of the

Composite sheet is dispensable. The dummy element therefore only needs to be provided where locally elevated temperatures can occur during resistance welding. To others

Therefore, circumstances need not be taken into account or only slight consideration. So it can also be tolerated if the dummy element is not permanently connected by the resistance welding with the composite sheet metal part, but sooner or later falls off the composite sheet metal part or removed. The dummy element can so for example only for the duration of resistance welding, so the joining, with the

Composite sheet metal part are brought into contact. Will that be

Dummy element for various welds and / or

Welding points reused, the dummy element can also be quite material-intensive, as a solid plate, made.

KJ / nb 110616WO April 23, 2012 It is, moreover, particularly simple and expedient that

Dummy element to bring into contact with the outer cover plate, which is not in contact with the overlapping with the other component, in particular when the further component and the composite sheet metal part are formed flat. In other words, the dummy element is preferably provided on the outer cover plate facing away from the further component.

The further component may be an ordinary sheet metal component. It is also conceivable that the further component is a solid metallic component or even a composite material, such as a composite sheet metal part. In order to ensure the weldability of the composite sheet metal part with the other component, the further component, if it is not constructed continuously metallic, in particular at least one outer metallic layer which can be brought into contact with the composite sheet metal part and welded. In a first embodiment of the method, at least one current path between the two electrodes via the

Dummy element and the two outer cover plates are closed. In this way it can be achieved that a part of the current flows through the dummy element, which would otherwise flow through an outer cover layer. When the dummy element is provided between an outer cover layer and the electrode so that the current flows through the dummy element into the outer cover layer or vice versa, the current density in the outer cover plate adjacent to the dummy element can be reduced. The dummy element may alternatively or additionally but also a part of the heat generated during welding

absorb and thus dissipate from an outer cover plate.

KJ / nb 110616WO April 23, 2012 Preferably, the electrode may be brought into abutment with the dummy element to approximately a current path through the

Ensure dummy element and example one

direct contact between the electrode and the

To avoid composite sheet metal part. The dummy element is then preferably associated with a composite sheet metal part

Electrode brought into contact.

Alternatively or additionally, a current path between the two electrodes can be closed via the dummy element and the electrically conductive component. The current path can be so, for example, under partial or preferably

complete bypass of the composite sheet metal part, closed. So can the composite sheet metal part gentler

Current path or an additional current path, which may be used to reduce the current density in the

Composite sheet metal part leads and so also to a

material-saving welding at lower thermal

Load leads.

A procedurally simple implementation can be achieved if the dummy element is received in an electrically conductive connected to the other component recording. The recording is preferably used at the same time

Positioning of the dummy element during welding. The recording or positioning of the dummy element is preferably carried out before the actual joining. However, the dummy element can also be taken up or positioned within certain limits only during joining. Alternatively or

In addition, the material and dimensions of the

Recording can also be used as control variables for adjusting current and heat fluxes. For example, it is conceivable

KJ / nb 110616WO April 23, 2012 that the resistance of the recording via a potentiometer or the like is adjustable.

It is particularly easy to use a recording which is fixed relative to one of the electrodes. Thus, it can be achieved that a predetermined relative positioning of the electrode and the dummy element is always maintained. faulty

Positionings of the dummy element during joining can thus be avoided.

Alternatively or additionally, a plurality of dummy elements provided on a carrier tape can be used. This is particularly advantageous when the carrier tape is moved between an electrode and the composite sheet metal part. This is preferably done between two

Joining events, where the join events are also two

may involve different composite sheet metal parts. Under a joining event, for example, the setting of a

Welding point or pulling a weld understood. The carrier tape can ultimately in a corresponding

be included automatic feed. Also in this case it is preferred if a holder for the carrier tape is fixed relative to an electrode. The positioning is preferably automatic. The carrier tape must then be transported only after a joining event a piece to a next dummy element again in the

To bring home position for a subsequent joining event.

A procedural simplification can be achieved if the plurality of dummy elements is separated from the carrier tape before or during the joining. The severed

Dummy elements can then be disposed of separately or on

KJ / nb 110616 O April 23, 2012 Stick composite sheet part. The separation can be

For simplicity, carried out by the electrode and / or the inclusion of the dummy elements. For this purpose, for example, the carrier tape perforations and / or the electrode or the recording, the dummy elements of the carrier tape

punch out.

The joining may be performed so that the dummy member adheres to the composite sheet member. The dummy element is finally welded during joining. This may be appropriate

Lead joining results. It may additionally be the case, however, that the dummy part adhering to the composite sheet metal part

Use or the properties of the composite sheet metal part in an undesirable manner influenced. To counteract this disadvantage, the dummy element after the joining event can be at least partially separated from the composite sheet metal part. This can be realized in a particularly simple manner by exerting a torsional force on the dummy element in order to

For example, at least parts of the dummy element of

Shear composite sheet metal part. The dummy element can also be wholly or partially by suitable means of cutting from

Composite sheet metal part to be removed. If the dummy element is to be partially removed, it may be expedient to provide at least one corresponding predetermined breaking point in the dummy element, which facilitates a separation of remaining and to be removed dummy parts.

In principle, dummy elements exert a favorable effect if they consist of a material of high electrical conductivity and high melting temperature. Thus, the electrical line in the current path via the dummy element and the

Form stability in joining favors. At particularly high

KJ / nb 110616WO April 23, 2012 Conductivities and melting temperatures of the dummy element can be achieved so that the dummy element is not joined to the composite sheet metal part. The dummy element can then be used repeatedly for a plurality of joining events, without being significantly damaged or having to be separated again from the composite sheet metal part. For simplicity, as well as to absorb larger amounts of heat and to be able to dissipate the composite sheet metal part, a solid plate can be used as a dummy element whose thickness is the thickness of the composite sheet metal part and / or an outer

Cover sheet can significantly exceed.

To the removal of the heat generated during joining

improve, may alternatively or additionally provided a cooling of the dummy element. If the dummy element is held in a receptacle, alternatively or additionally, the receptacle can be cooled. As cooling medium are water, oil or other fluid in question. The cooling can be done via appropriate cooling channels.

It can often not be excluded when joining that due to the heat from the at least one

non-metallic layer of composite sheet metal gases

leak out or gases are released. In this case, a dummy element and / or a recording with

Engraving are used. The embossments, such as in the form of thorns, thereby piercing an outer cover plate.

Gases from a non-metallic layer can then be removed by at least one corresponding venting channel.

KJ / nb 110616WO April 23, 2012 _"

10

It has been shown that good results are achieved when joining, if the dummy element is wider than the expected weld. In the case of spot welding, the same applies to dummy elements having a diameter greater than the diameter of the spot weld or weld zone. With appropriate dummy elements, a

sufficient amount of heat dissipated and / or the current density in the corresponding current path are sufficiently reduced. Particularly preferably, the described method can be used in resistance spot welding. There is only a selective amount of heat in the

Inserted composite sheet metal part and it can be particularly simple and inexpensive dummy elements, such as in the form of

circular metal discs or the like can be used.

The aforementioned, the invention is based

The object is achieved in a device of the type mentioned also according to claim 15, characterized in that a receptacle for receiving a dummy element before and / or during joining and for contacting the dummy element is provided with the composite sheet metal part and that the receptacle electrically conductive with the further component connected is.

This achieves the advantages already described above in connection with the use of at least one receptacle. From the above description in connection with the method, there are also other preferred embodiments of the device according to the invention. These will be readily apparent to those skilled in the art.

KJ / nb 110616WO April 23, 2012 _, _

11

The invention as a whole is described below with reference to a

merely exemplary embodiments illustrative drawing explained in more detail. In the drawing, Fig. 1 shows a first embodiment of

Device according to the invention in carrying out a first embodiment of the invention

inventive method in a schematic Schnittansieht,

Fig. 2 shows the device of Fig. 1 in a schematic

View from above,

Fig. 3 a with the first embodiment of the

produced process according to the invention

Workpiece in a schematic sectional view,

Fig. 4 shows a second embodiment of

Device according to the invention in carrying out a second embodiment of the invention

inventive method in a schematic Schnittansieht,

Fig. 5 a with a third embodiment of the

produced process according to the invention

Workpiece in a schematic sectional view, a workpiece during the implementation of a fourth embodiment of the method according to the invention in a schematic sectional view,

KJ / nb 110616WO April 23, 2012 7 shows a workpiece during the implementation of a fifth exemplary embodiment of the method according to the invention in a schematic view from above, FIGS. 8a-b shows a section of a section of a third embodiment of the device according to the invention,

9 shows a fourth embodiment of the

device according to the invention during the

Carrying out a sixth embodiment of the method according to the invention in a schematic sectional view and Fig. 10 shows a fifth embodiment of

Device according to the invention during the implementation of a seventh embodiment of the method according to the invention in a schematic sectional view.

In FIGS. 1 and 2, a device 1 for joining by means of resistance welding, in particular by means of

Resistance spot welding, shown. In the device 1 are a composite sheet metal part 2 and another component 3. The composite sheet metal part 2 includes in the illustrated and so far preferred embodiment, two outer

Cover plates 4.5 and an inner non-metallic layer 6 made of plastic, while the other component 3 by a

ordinary sheet is formed.

The composite sheet metal part 2 and the further component 3 are in the one shown in Figs. 1 and 2, each other

KJ / nb 110616 O April 23, 2012 _, _

13

overlapping, position joined together, by means of two welding points. For this purpose, the composite sheet metal part 2 and the further component 3 between the two electrodes 7,8 of a welding tongs 9 of a resistance welding unit

brought, which surrounds both the composite sheet metal part 2 and the further component 3 partially. To the electrodes 7,8 of the welding gun 9, a potential difference is applied via a voltage supply 10, not shown. The lower electrode 8 contacts the further component 3. The upper electrode 7 makes contact with a circular disk-shaped dummy element 11 which is in contact with the further component 3

remote outer cover 4 is placed. The dummy element 11 is thus provided between the outer cover plate 4 and the upper electrode 7, so that a direct contact between the electrode 7 and composite sheet metal part 2 is not given. In the illustrated preferred embodiment, the thickness of the circular disk-shaped Dummyelernents 11 is tuned to the welding task. The thickness of the

circular disk-shaped dummy element 11 can thereby

for example, be about 1 mm. In addition, the upper

Electrode 7 have a higher compared with the lower electrode 8 contact resistance.

At the edge of the composite sheet metal part 2 shown on the right, a current bridge 12 is provided, which is the edge of the

Composite sheet metal part 2 slightly engages around and is electrically conductive. The current bridge 12 consequently ensures that during the joining a current path is formed between the two electrodes 7, 8 via the dummy element 11, the upper outer cover plate 4, the current bridge 12, the lower outer cover plate 5 and the further component 3. The current bridge 12 thus represents an electrically conductive connection between the outer nb 110616WO April 2012 Covering sheet 4.5 is a further current path between the electrodes 7,8 is closed via the dummy element 11, a receptacle 13, a connection 14 between the receptacle 13 and the further component 3 and the further component 3. Especially the parallel formation of the two current paths ensures particularly good joining results.

The receptacle 13 serves to receive the dummy element 11 and the positioning of the dummy element 11 in the desired orientation to the composite sheet metal part 2. For this purpose, the receptacle 13 is formed in the manner of a pliers, so that the receptacle 13 for insertion of the dummy element 11 is expanded or opened and can then be narrowed or closed for fixing or at least contacting. This is shown in particular in FIG. 2. The receptacle 13 may be stationary connected to the welding gun 9, but this is not required. Further, the receptacle 13 is connected in the illustrated embodiment via a connection 14 in the form of a flexible cable or a tape with the other component 3, in particular, to multiple welds

to be able to set different positions of the other component 3. In the illustrated embodiment, two welding points are to be set. Office place of the second

Welding point is already another kreischeibenförmiges dummy element 11 is provided. In order to apply the dummy elements 11 before the respective joining, without the risk of accidental misalignment, or when the surface of the composite sheet metal part is inclined, the dummy elements 11 can be glued to the composite sheet metal part 2.

KJ / nb 110616WO April 23, 2012 In Fig. 3, the workpiece comprising the

Composite sheet metal part 2 and the further component 3 shown after joining in a lateral section. The welding zones 15 of the spot welds are lenticular, as so-called

Nugget, trained and have a slightly smaller diameter than the associated dummy elements 11. The difference in diameter could, if necessary, but still significantly larger. In the illustrated and insofar preferred embodiment, the extend

Welding zones 15 on one side to the other

Component 3 in and on the other side into the outer component 4 facing away from the outer cover plate 4 inside.

Consequently, the dummy elements 11 have been added and also remain subsequently adhere to the composite sheet metal part 2.

In the device 20 shown in FIG. 4, a receiving web 21 is provided, which has a circumferential recess 22. In this circumferential recess 22 can

Dummy elements 11 are precisely recorded. In addition, a very secure positioning of the dummy elements 11 is possible by the inclusion of 21 in the context of an undercut.

Furthermore, in the illustrated device 20 is an only partially shown automatic feeder 23 of

Dummy elements 11 provided to the individual welds. For this purpose, the individual dummy elements 11 are fixed in succession on a carrier tape 24. The carrier tape 24 is rolled up and is clamped in the automatic feeder 23. In the period between the setting of two successive welds, the carrier tape 23 becomes a piece

further transported until a next dummy element 11 assumes the starting position for joining, which already has the

KJ / nb 110616WO April 23, 2012 Previous dummy element 11 has taken. Thereafter, the welding gun 9 is closed, wherein, if necessary, the next dummy element 11 is punched out by the electrode 7 and / or the receptacle 21. In this case, the dummy element 11 is contacted with the composite sheet metal part 2 and the

Resistance spot welding per se can be done. This essentially takes place as previously described. To that

Punching or generally to facilitate the separation of the dummy element 11 from the carrier tape 24, the carrier tape 24 corresponding weakenings, such as in the form of perforations on iron.

In the illustrated and so far preferred

Embodiment, the carrier tape 24 is transported through the space between the composite sheet metal part 2 and the upper electrode 7. However, the transport of the carrier tape 24 could also take place outside this gap and the

Carrier tape 24 are each introduced into the space after the next dummy element 11 has taken the desired position in the automatic feeder 23.

A workpiece produced by a modified method comprising a composite sheet metal part 2 and a further component 3 is shown in FIG. 5 in a sectional view. The

In this case, the method is modified so that the welding zone 15 extends only from the further component 3 into the outer cover plate 4 of the composite sheet metal part 2 facing away from the further component 3. The dummy element 25 is not firmly connected in this case by the joining of the composite sheet metal part 2 with the other sheet metal part 3 with the composite sheet metal part 2. The dummy element 25 can therefore be reused to set the next welding point, which is due to the

KJ / nb 110616WO April 23, 2012 Arrow in Fig. 5 is shown. In the corresponding method, a particularly conductive and thermally stable dummy element 25 is used. Since the dummy element 25 can be reused, correspondingly higher material costs for the dummy element 25 do not constitute a significant disadvantage.

In the event that the dummy elements 11 are joined during joining with the composite sheet metal part 2, the joining process can be supplemented by a step shown in FIG. 6. In this case, after the joining, a rotating punch 26 or the like is pressed against the dummy element 11, thus exerting a torsional force on the dummy element 11. If the torsional force or the moment exerted on the dummy element 11 are large enough, the dummy element 11 will become as a whole

sheared. The remaining welding zone 15 'is shown on the left in FIG. 6.

In Fig. 7 is a workpiece comprising a

Composite sheet metal part 2 and another component 3, shown, which is subjected to a slightly modified process.

Dummy elements 27 are used, the so-called

Have predetermined breaking points 28 with reduced material thickness or other weakening of the material. Such a dummy element 27 is on the left side of FIG. 7

shown. The shown with dashed lines

Predetermined breaking points 28 are designed so that the

Dummy element 27 is partially destroyed when a

Torsionskraft is impressed, as has been described in connection with FIG. 6. An inner part 29 of the dummy element 27 connected directly to the welding zone thus remains on the composite sheet metal part 2. The on the

KJ / nb 110616 O April 23, 2012 _

18

Composite sheet part 2 remaining part 29 of the dummy element 27 is shown on the right and has approximately the size of the expected bite point or the area of the dummy element 27 joined to the composite sheet metal part 2.

In FIGS. 8a and 8b, a part of a receptacle 30 of a device for joining by means of resistance welding is shown

shown. The illustrated and so far preferred

Receipt 30 has a circular opening 31 and a

circular, concentric with the opening 31 arranged

Recess 32, in which a correspondingly formed dummy element can be accommodated. However, the receptacle and the opening could also be formed differently than circular and / or not concentric with each other.

The receptacle 30 further has a holder 33, via which the dummy element is conductively connected to the further component. For cooling the receptacle 30, a cooling channel 34 is provided, which in the illustrated and in so far

preferred receptacle 30 is annular. Of the

Cooling passage 34 can be traversed by a cooling medium to dissipate the heat generated during resistance welding. The cooling channel 34 is formed in the illustrated and so far preferred receptacle 30 so that it during the joining adjacent to the dummy element and adjacent to

Composite sheet metal part is. Thus, both the composite sheet metal part and the dummy element heat can be dissipated. Alternatively or additionally, the dummy element could have cooling channels, which may be ventilated. The cooling channels of the dummy element could also be separated or via the recording with a

Coolant are supplied, so that the cooling channels of the dummy element are flowed through by coolant.

KJ / nb 110616WO April 23, 2012 Further, in the case of the receptacle 30 shown in FIGS. 8a and 8b, puncturing embossments 35 are provided in the form of mandrels which can penetrate an outer cover plate of a composite sheet metal part when the receptacle 30 is pressed against the composite sheet metal part. The embossings 35 then protrude into the at least one non-metallic layer. Through a hole 36 in each of

Engraving 35 and one of these holes 36th

connected ventilation channel 37 can escape gases released during joining in the non-metallic layer. The embossings 35 are in the illustrated and so far preferred embodiment of an electrically non-conductive material, such as a ceramic,

manufactured to prevent sparking that may occur during high welding currents.

In Fig. 9 is a device 40 for joining two composite sheet metal parts 2 by means of resistance welding

shown. The basic principle of joining corresponds to the previously described principle with which

Special feature that it is in the other component 3

also is a composite sheet metal part. Therefore, a dummy element 11 is brought between each electrode 7,8 of the welding gun 9 and the associated composite sheet metal part 2 and the further component 3 in the form of a composite sheet metal part, by means of a receptacle 21 of the type already described. Each receptacle 21 is with the opposite Composite sheet metal part 2 and the other component 3 electrically connected. These connections 14 are each provided via a current bridge 41, which in turn electrically conducts the two outer cover plates 4, 5 of the composite sheet metal part 2 on the one hand and of the further component 3 on the other hand

KJ / nb 110616WO April 23, 2012 connect with each other. This results in four different current paths between the two electrodes 7, 8. Each of these current paths runs through both

Dummy elements 11, since both electrodes 7.8 each

exclusively via a dummy element 11 in conductive contact with the workpiece. Two of the current paths run through an outer cover plate 4 each. A current path runs through the two outer cover plates 5 contacting one another and a further current path through all four outer cover plates 4, 5.

FIG. 10 shows a device 45 modified relative to the device 40 illustrated in FIG. 9 for joining a composite sheet metal part 2 and a further component 3 designed as a composite sheet metal part by means of resistance welding. In the method performed with this device 45 is dispensed with the use of images for receiving dummy elements. It will be too

omitted, respectively between the electrodes 7,8 and the

Composite sheet metal part 2 on the one hand and the formed as a composite sheet metal part further component 3 on the other hand a

Provide dummy element. Rather, the outer ones

Cover plates 4 of the composite sheet metal part 2 and further

Component 3 via two dummy elements 11 and a

Current bridge 12 electrically conductively connected to each other, wherein the cover plates 4.5 are each directly in contact with a dummy element 11.

It results in the joining only a current path between the two electrodes 7,8, by all four outer

Cover plates 4,5 and all four dummy elements 11 runs. The contact surfaces between each dummy element 11 and the corresponding outer cover plate 4, 5 are small enough,

KJ / nb 110616WO April 23, 2012 so that not only the composite sheet metal part 2 are joined to the further component 3 in the form of a composite sheet metal part, but also the outer cover plates 4.5 of the

Composite sheet metal part 2 on the one hand and the other component 3 on the other hand, as shown in FIG

Illustrate weld zones 15, 46. The dummy elements 11 can also be joined with the associated outer cover plates 4, 5. However, a subsequent separation of the dummy elements 11 from the outer cover plates 4, 5 is possible as required.

KJ / nb 110616WO April 23, 2012

Claims

Patent claims

Method for joining a composite sheet metal part (2) to a further component (3), wherein the composite sheet metal part (2) has at least two outer cover plates (4,5) and at least one arranged between the cover plates (4,5).

has a non-metallic layer (6) and the further component (3) has at least one outer metallic layer (4,5),

in which the composite sheet metal part

(2) and the other component

(3) are placed overlapping one another between two electrodes (7, 8) of a resistance welding unit,

in which an electrically conductive dummy element (11,25,27) is brought into contact with an outer cover plate (4,5) and

in which at least one current path between the two electrodes (7,8) via an electrically conductive

Dummy element (11,25,27) is closed.

Method according to claim 1,

in which a current path between the two electrodes (7,8) is closed via the dummy element (11,25,27) and the two outer cover plates (4,5).

Method according to claim 2,

in which the dummy element (11,25,27) is brought into contact with an electrode (7) assigned to the composite sheet metal part (2).

4. Method according to one of claims 1 to 3, in which a current path between the two electrodes (7,8) via the dummy element (11,25,27) and the further component (3), preferably bypassing the composite sheet metal part (2) , is closed.

5. Method according to claim 4,

in which the dummy element (11,25,27) is received in a receptacle (13,21,30) which is electrically conductively connected to the further component during and/or before joining.

6. Method according to claim 5,

in which one opposite one of the electrodes (7,8)

fixed recording (13,21,30) is used.

7. Method according to one of claims 1 to 6,

in which a plurality of dummy elements (11, 25, 27) are provided on a carrier tape (24) and in which,

preferably, the carrier tape (24) is moved through the space between an electrode (7) and the composite sheet metal part (2).

8. Method according to claim 7,

in which the plurality of dummy elements (11,25,27) come from the electrode (7) and/or the receptacle (21).

Carrier tape (24) must be separated.

9. Method according to one of claims 1 to 8,

in which the dummy element (11,25,27) is connected to the composite sheet metal part (2) during joining and in which the

Dummy element (11,25,27) after joining at least

KJ/nb 110616WO April 23, 2012 is partially separated from the composite sheet metal part (2), preferably sheared off or removed by cutting.

10. Method according to one of claims 1 to 8,

in which the dummy element (11,25,27) is made of a material with high electrical conductivity and high

Melting temperature exists, the dummy element (11,25,27) is not joined to the composite sheet metal part and in which the dummy element (11,25,27) is for a plurality of

joining events is reused.

11. Method according to one of claims 1 to 10,

in which the receptacle (30) and/or the dummy element are cooled, preferably water-cooled.

12. Method according to one of claims 1 to 11,

in which a receptacle (30) with stitch embossings (35) for penetrating an outer cover plate (4,5) and,

preferably, for degassing a non-metallic

Layer (6) is used.

13. Method according to one of claims 1 to 12,

in which the dummy element (11,25,27) is wider than the expected welding zone.

14. Method according to one of claims 1 to 13,

in which the joining is resistance spot welding.

15. Device for joining a composite sheet metal part (2).

another component (3), wherein the composite sheet metal part

(2) at least two outer cover plates (4,5) and

at least one between the cover plates (4,5)

KJ/nb 110616WO April 23, 2012 arranged non-metallic layer (6) and wherein the further component (3) has at least one outer metallic layer (4,5),

with a resistance welding unit comprising at least two electrodes (7,8) and with a receptacle (13,21,30) for receiving a dummy element (11,25,27) before and/or during joining and contacting the dummy element (11,25, 27) with the composite sheet metal part (2), whereby the

Recording (13,21,30) is electrically connected to the further component (3).

KJ/nb 110616WO April 23, 2012