DE102012025108A1 - Joint for connecting two laminated components for blind rivet in motor car, has rivet case formed with inner layer and outer layer that are made of high strength material and low strength material - Google Patents

Abstract

The joint (2) has components (4, 6) connected with each other by a blind rivet (8), which is provided with a rivet case (12) and a mandrel (18). The rivet case is formed with an inner layer (12A) and an outer layer (12B) that are made of a high strength material and a low strength material, where wall thickness of the inner layer is less than wall thickness of the outer layer. The rivet case is electrically insulated to the components. The inner layer is widened in the rivet case on a shaft end, where diameter of the mandrel is less than or equal to wall thickness of the rivet case. The outer layer is designed as an overmolded casing. An independent claim is also included for a rivet case for a blind rivet.

Description

The invention relates to a joint connection between two components, in particular for a motor vehicle, of which at least one consists of a fiber-reinforced plastic. The invention further relates to a blind rivet for such a joint connection.

Due to the desired lightweight construction, especially in the automotive sector, efforts are being made to use fiber composite materials in the motor vehicle which exhibit very good mechanical properties with a low specific weight. In comparison to steel sheets still commonly used in mass production today, such fiber composite materials, for example CFRP components, can be fastened to one another or to other components only with great effort. Due to the high level of automation in the automotive industry, a joining process must allow a high process cycle and, moreover, be fault-tolerant with regard to alignment inaccuracies of the components to be joined.

Proceeding from this, the object of the invention is to enable a joint connection between two components, in particular components for the motor vehicle sector, in which at least one of the components is a fiber composite component.

The object is achieved according to the invention by a joint connection with the features of claim 1, as well as with a rivet sleeve with the features of claim 15 and with a blind rivet for such a joint connection.

Preferred developments are laid down in the subclaims. The object is further achieved by a rivet and a blind rivet according to the further independent claims.

Thereafter, it is provided that the rivet sleeve shows a multilayer, in particular two-layered structure, at least in the region of the sleeve shaft, wherein the two layers are formed of materials with different strength and the outer, applied to the components to be joined layer consists of a material with lower strength , Other layers are preferably not provided, the rivet sleeve is therefore formed a total of two-ply.

The outer layer is therefore significantly softer compared to the inner layer, so that only comparatively small forces are exerted during the setting process on the components, in particular on the edges of the hole edge. As a result, damage to the fiber-reinforced component, in particular so-called delamination, is avoided during the setting process. The at least one fiber-reinforced component is designed in particular as a carbon-fiber-reinforced component (CFRP component). This plastic component is in particular a laminate component, which is constructed from a plurality of laminate layers.

The outer layer thus forms as it were a protective layer for the components. At the same time sufficient strength of the Gesamtriethülse is achieved by the higher-strength inner layer of the rivet. Due to the division into two different layers, therefore, the properties of the rivet can be optimally adapted to different, partially opposing requirements.

Preferred embodiments of the rivet sleeve can be found in the subclaims.

Thereafter, it is provided in particular that the inner layer consists of a preferably corrosion-resistant metal, in particular stainless steel. The strength of the rivet sleeve can be adjusted - especially with the same wall thickness - by heat treatment (curing) in desired areas, so that a rivet sleeve with the same dimensions, but different strengths for different applications (strength requirements) can be used.

The outer layer is preferably made of a plastic, in particular an unreinforced plastic such as polyamide or the like.

The inner layer preferably has a significantly higher strength than the outer layer, the strengths differ in this case in particular by a multiple, at least by 2 to 5 times.

Expediently, different wall thicknesses are furthermore provided for the different layers, wherein in particular the inner layer has a significantly smaller wall thickness. The wall thickness of the inner layer is preferably less than 0.5 mm and is in particular below 0.2 mm or 0.1 mm.

The outer layer, by contrast, expediently has a wall thickness> 0.5 mm, in particular> 0.75 mm or even> 1 mm. The comparatively thick wall thickness ensures reliable protection of the components.

The outer layer is formed in particular in the manner of an overmolded shell, ie, the outer layer is expediently applied in a Kunstsoff injection molding process. The outer layer is in particular at the rivet sleeve educated. Preferably, it extends over the entire sleeve, so it is also formed on the underside of the setting head of the rivet and lies with the outer layer so that on the upper part of the joint flat on.

Furthermore, a seal over the rivet sleeve preferably takes place via the outer layer of the sleeve, which is softer than that of the components, so that the riveted joint as a whole sealingly connects the components. The sealing effect is achieved by the softer sleeve, which thus clings to the harder components during the setting process in particular by elastic or plastic deformation.

The blind rivet is preferably corrosion-resistant and furthermore, at least the outer layer of the rivet sleeve is electrically insulating. In particular, in a preferred mixed connection of components of different materials, ie in particular in a compound of a metal component, such as an aluminum or steel sheet, with the CFRP component electrical insulation of the two components from each other is essential to prevent corrosion of the metallic component ,

In an expedient development, the inner layer at the end of the sleeve shaft is widened or bent, so that an approximately funnel-shaped sleeve opening is formed. This is of particular importance for the setting process, since a rivet mandrel is reliably guided over this funnel-shaped opening. In particular, this ensures that the setting forces transmitted via the rivet mandrel to the rivet sleeve are reliably introduced.

Despite the conical expansion of the inner layer, the outer diameter of the sleeve shank of the rivet sheath preferably remains constant, d. H. the rivet sleeve as such does not expand at the shaft end. The sleeve shaft therefore has a constant outer diameter over its entire length.

The inner layer is preferably guided in the widened end region up to the outer maximum diameter of the rivet sleeve, thus forming the outer end edge of the rivet sleeve at the front end of the sleeve shaft.

The opening angle of the widened region, ie the angle at which the widened region is oriented with respect to a central longitudinal axis of the sleeve shaft, is preferably in a range between 30 ° and 60 ° and in particular in a range of 45 °.

Nowadays, in the production of motor vehicle components, the procedure is usually such that the entire body is immersed in a bath for applying a protective lacquer, namely in a so-called cathodic dip bath (cathodic dip coating). In this bath, a temperature in the range of about 180 to 190 ° C prevails. The body is immersed in it for about half an hour. The blind rivet must be temperature resistant in order to withstand this load.

The two components are preferably glued together with the help of an adhesive over the entire surface. The adhesive is a thermosetting adhesive. Curing is preferably carried out in the cathodic dip bath.

The blind rivets, via which the two components are connected to each other, therefore serve to fix the two components together until the adhesive has cured.

In addition, the blind rivets also contribute to the strength of the joint connection when the joint connection is completed. This applies in particular to forces occurring in the axial direction, ie perpendicular to the component surfaces. The forces parallel to the connecting plane between the two components are usually already very well received via the adhesive bond. Especially since the CFRP components typically have laminated components impregnated with plastic resin tissue, which is preferably in all directions in the same way resilient.

The rivet mandrel preferably has increased strength compared to the rivet sleeve. In particular, it is made of stainless steel. Basically, a rivet pin made of steel is used. However, under certain circumstances there is the problem of corrosion, in particular the breaking point of the residual mandrel after the setting process.

In general, the blind rivet is preferably designed such that as large a contact surface as possible is formed both on the sides of the setting head and on the sides of the closing head in order to keep the surface pressure per unit area small, in order to avoid damage to the CFRP component as far as possible.

In an expedient embodiment, it is provided for this purpose that the wall of the rivet sleeve to be deformed via the mandrel head is comparatively large. Thus, a comparatively thick-walled rivet sleeve is used in order to achieve the widest possible closing head. The comparison refers here to conventional steel rivets. In particular, it is provided that the wall thickness of the rivet sleeve compared to the diameter of the rivet mandrel is very large and, for example, at least 70% of the diameter of the residual mandrel and beyond, for example, greater than the diameter of the residual mandrel.

In order to enable a fault-tolerant, automated joining with high cycle speed is provided in particular that the upper, the setting head facing component has a larger hole diameter than the underlying (CFK) component. As a result, positional inaccuracies of the two mutually oriented components can be easily compensated, without shearing forces acting on the blind rivet.

Appropriately, it is further provided that the remaining space between the rivet and the hole wall of the upper member is filled with an adhesive, as for example in the DE 10 2008 026 356 A1 is described.

The components are usually pre-punched components in which the holes are positioned as close together as possible.

To form the joint connection is therefore generally proceeded such that the curable adhesive is applied to at least one of the components on the surface over its entire surface over the entire surface, then that the second component is as accurate as possible attached to the first component / positioned, so that the holes for the blind rivets are aligned as possible. Subsequently, the blind rivets are inserted into the respective through holes and set with the usual Blindniet-setting process. For this purpose, it is pulled by means of a setting tool on the rivet mandrel in the axial direction, so that the mandrel head is pulled into the rivet and this is thereby formed to form the closing head. The rivet mandrel travels on reaching a predetermined setting force at a predetermined breaking point, which is usually arranged in the interior of the rivet, so that a residual mandrel remains in the rivet sleeve. Subsequently, the assembled components, which may in particular also be the subject of a complex component, for example an entire body, immersed in a hot cathodic dip bath and subjected there to a paint job. In this treatment, the thermosetting adhesive cures completely between the components to be joined.

The setting process is automated, in particular fully automatic, for example, within a production line and with a blind riveting robot (as he, for example, in WO2006 / 056255 A1 is described), which automatically moves to the required position and fully automatically performs the setting process

Embodiments of the invention will be explained in more detail with reference to FIGS. These show:

1 in a schematic representation of a cross section through a joint connection between two components with a blind rivet with a multi-layered rivet,

2a a partially sectioned side view of a multi-layer rivet sleeve according to the invention,

2 B an enlarged view of the in 2a area marked with a circle and

2c a perspective view of the rivet according to 2a ,

In the figures, like-acting parts are provided with the same reference numerals.

At the in 1 shown joint connection 2 are two components 4 . 6 with the help of a blind rivet 8th connected with each other. For the components 4 . 6 These are preferably motor vehicle components, in particular sheet-like, large-area components. At least one of the two components 4 . 6 , In the embodiment, the lower component 6 is formed as a laminated plastic component, in particular as a CFRP component. In the exemplary embodiment, the upper component 4 in contrast, designed as a metal component, in particular steel component.

The two components 4 . 6 are in the embodiment of 1 in addition to the riveted connection over the blind rivet 8th still glued together. For this purpose, in particular a full-surface bonding is provided by means of a curable adhesive. Between the two components 4 . 6 is therefore still an adhesive layer 10 educated.

In the exemplary embodiment, the two components 4 . 6 one pre-perforation with identical diameter. Deviating from this, it is preferably provided that the upper component 4 has a larger hole diameter, so that an automated joining process of the two components 4 . 6 is relieved. Especially for larger components that have multiple blind rivets 8th attached to each other, this is advantageous to location inaccuracies in the positioning of the two components 4 . 6 to be able to compensate. The clearance between the blind rivet and the enlarged hole diameter of the upper component 4 is expediently also filled with adhesive.

The blind rivet 8th includes a rivet sleeve 12 with a set head 14 and in the assembled state one closing head 16 , In the rivet sleeve, a residual mandrel of a rivet mandrel is in the assembled final state 18 with a thorn head 20 one.

The rivet sleeve 12 turn, is multi-layered from an inner situation 12A as well as an outer layer 12B educated. The inner situation 12A consists of a higher-strength material than the outer layer 12B , In particular, there is the inner situation 12A made of metal, preferably of stainless steel. The inner situation 12A itself therefore forms an independent metal sleeve. The same applies to the outer layer 12B which consists of a soft material, in particular plastic. As a plastic, for example, a polyamide, in particular a polyamide 4.6 or the like is used.

Through this special two-layer design with a higher-strength inner sleeve 12A and a soft sheath 12B On the one hand, high forming and setting forces can be exerted during the setting process. At the same time, the risk of damage, in particular a delamination of the plastic component 6 kept low or avoided. Due to the soft plastic material of the outer layer 12B act on the individual laminate layers of the CFRP component 6 only low separation forces. The outer situation 12B is therefore deformed without the CFRP component 6 is damaged.

Another advantage of the soft outer layer 12B is to be seen in that over this external situation 12B a seal to the two components 4 . 6 takes place. Finally, at the same time an isolation is achieved in electrical terms. At one in the 1 illustrated hybrid connection between a CFRP component 6 and a metal component 4 namely, to avoid as much as possible an electrically conductive connection between the two components.

The structure of the rivet sleeve 12 in the unactivated state before the actual assembly is out of the 2a to 2c refer to. As can be seen, the inner layer has a wall thickness d1, which is smaller by a multiple than the wall thickness d2 of the outer layer. In the exemplary embodiment, the wall thickness d2 is more than 5 times greater than the wall thickness d1 of the inner layer 12A , The rivet sleeve 12 points next to the setting head 14 an adjoining sleeve shaft 22 on, which is hollow cylindrical and has a constant outer diameter over its entire length.

At the setting head 14 facing away from the shaft end is the inner layer 12A widens and forms a funnel-shaped shaft opening 24 out. The funnel walls in particular run in a straight line and, with the formation of a radius, merge into the shank region extending parallel to the central longitudinal axis. The sleeve walls are oriented at an angle α to a central longitudinal axis, which is in the embodiment in the range of about 45 ° and is generally in the range between 30 ° and 60 °. The inner situation 12A is up to the outer circumference of the rivet sleeve 14 guided, therefore forms at the front end side the peripheral edge of the rivet sleeve 12 out. Accordingly, the outer layer 12B in this funnel area on a taper, so runs in a wedge shape. The outer diameter of the rivet sleeve remains constant in this area.

During the setting process comes the rivet mandrel 16 in contact with this funnel-shaped shaft opening 24 , so that the setting and forming forces on the inner layer 12A on the rivet sleeve 14 be transferred and their transformation and in particular to the formation of the closing head 16 to lead.

LIST OF REFERENCE NUMBERS

2

Retaining compound

4

steel component

6

CFRP component

8th

Rivet

10

adhesive layer

12

rivet sleeve

12A

inner situation

12B

outer location

14

setting head

16

closing head

18

Mandrel

20

mandrel head

22

sleeve shank

24

funnel-shaped shaft opening

α

angle

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 102008026356 A1 [0030]
• WO 2006/056255 A1 [0033]

Claims (16)

Joint connection ( 2 ) between two components ( 4 . 6 ), in particular for a motor vehicle, at least one of which consists of a fiber-reinforced plastic, the components ( 4 . 6 ) with the help of at least one blind rivet ( 8th ), wherein the blind rivet ( 8th ) a rivet sleeve ( 12 ) and a rivet mandrel ( 18 ), characterized in that the rivet sleeve ( 12 ) is multi-layered with an inner layer ( 12A ) of a higher strength material and an outer layer ( 12B ) made of a low-strength material. Joint connection ( 2 ) according to claim 1, characterized in that the inner layer ( 12A ) is made of a metal, in particular of stainless steel. Joint connection ( 2 ) according to one of the preceding claims, characterized in that the outer layer ( 12B ) consists of plastic. Joint connection ( 2 ) according to one of the preceding claims, characterized in that the strength of the higher-strength material is at least 2 to 5 times the strength of the lower-strength material. Joint connection ( 2 ) according to one of the preceding claims, characterized in that the wall thickness (d1) of the inner layer ( 12A ) is less than the wall thickness (d2) of the outer layer ( 12B ). Joint connection ( 2 ) according to one of the preceding claims, characterized in that the wall thickness (d1) of the inner layer ( 12A ) is less than 0.5 mm, preferably less than 0.2 mm or 0.1 mm. Joint connection ( 2 ) according to one of the preceding claims, characterized in that the wall thickness (d2) of the outer layer ( 12B ) is greater than 0.5 mm, in particular greater than 0.75 or greater than 1 mm. Joint connection ( 2 ) according to one of the preceding claims, characterized in that the outer layer ( 12B ) is formed as a molded jacket. Joining connection according to one of the preceding claims, characterized in that the outer layer ( 12B ) at the bottom of a setting head ( 14 ) of the rivet sleeve ( 12 ) is continued. Joint connection ( 2 ) according to one of the preceding claims, characterized in that the rivet sleeve ( 12 ) to the components ( 4 . 6 ) is electrically insulating. Joint connection ( 2 ) according to one of the preceding claims, characterized in that the inner layer ( 12A ) of the rivet sleeve ( 12 ) is widened at a shaft-side end, in particular without an outer diameter of the rivet sleeve ( 12 ) is enlarged. Joint connection ( 2 ) according to one of the preceding claims, characterized in that the components ( 4 . 6 ) are made of different material. Joint connection ( 2 ) according to one of the preceding claims, characterized in that the two components ( 4 . 6 ) are additionally bonded together in particular over the entire surface. Joint connection ( 2 ) according to one of the preceding claims, characterized in that the diameter of the rivet pin is less than or equal to the wall thickness of the rivet sleeve. Rivet sleeve ( 12 ) for a blind rivet ( 8th ) with a sleeve shaft ( 22 ) and a setting head ( 14 ), characterized in that at least the sleeve shaft ( 22 ) is multi-layered with an inner layer ( 12A ) of a higher strength material and an outer layer ( 12B ) made of a low-strength material. Blind rivet ( 8th ) for a joint connection according to one of claims 1 to 14.

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