ARRANGEMENT OF TWO COMPONENTS RIVETED TOGETHER

Abstract

An arrangement comprising a component (1) and a further component (2) which are connected to one another by riveting by means of at least one rivet mandrel (10) formed on the further component (2), wherein the rivet mandrel (10), when guided through a through-opening (11) formed in the component (1) and a projecting end of the rivet mandrel (10) is deformed, forms a rivet head (30), wherein the through-opening (11) is formed in a weakened region (13) of the component (1) which has a lower breaking load than the adjacent region of the component (1) and a lower breaking load than the formed rivet, wherein the further component (2) is made of a thermoplastic material, characterized by one or more of the following features: - the weakened region (13) has a groove (14) which is formed in a surface of the component (1) facing the further component (2), wherein the through-opening (11) is formed in a groove base of the groove (14) which has a slit in a longitudinal direction of the weakened region (13), and a width of the slit is smaller than an outer diameter of the rivet mandrel (10); - the weakened area (13) is at least partially perforated; - the weakened area (13) has an elongated hole (130) filled with a foamy and / or porous material (131); - the weakened region (13) has a width (W) which is designed such that it tapers in a longitudinal direction of the weakened region (13).

Description

TECHNICAL FIELD

[0001] The invention relates to an arrangement of two components riveted together. STATE OF THE ART

[0002] In riveted joints, sudden load events such as the impact of a motor vehicle against an obstacle can cause the riveted joint to tear immediately. This can create sharp edges that pose a significant risk of injury in the interior of a motor vehicle, particularly if an airbag system has not yet deployed or has not fully deployed. This danger is particularly acute when the rivet holes are designed as circular through-holes, as an overload acts directly and undamped on the rivet. It is common practice to design rivet holes as elongated holes instead of round holes to allow the rivet shank to deflect, thus delaying or even preventing the riveted joint from tearing apart. Elongated holes can also prevent or compensate for distortion of the components that could arise, for example, from different thermal expansion.

[0003] If the rivet connection is created by hot riveting, where one end of the rivet is melted to create the rivet head, the molten material can flow into the slotted hole, making reliable formation of the rivet head difficult or even impossible. Hot riveting is particularly common with plastic parts where the rivet shank is already formed as a rivet mandrel. The plastic part could, for example, be a trim part that is to be attached to a support part on the body or to a vehicle door. But even with other rivet materials, the material that flows during deformation can escape into the slotted hole, which can disfigure the rivet head from the outset. The material can also come into contact with the slotted hole and fuse with it, so that the rivet head is firmly bonded to the slot, which is often undesirable.Even if the rivet head is formed cleanly, the fit of the rivet shank in the slot may already be too loose during normal operation or may loosen over time, so that the fit of the components is no longer tight and the components show increasing play between each other.

[0004] DE 10 2006 012 043 A1 discloses a method for riveting components by thermally deforming a mandrel provided on a first component against a round or elongated hole formed in the second component. By providing a sliding layer, the rivet is prevented from adhering to the second component, thus creating a movable connection.

[0005] EP 1 773 570 B1 discloses the riveting of an accessory in a plastic container, wherein a part of the container wall is melted and pressed through an opening of the accessory without being detached from the rest of the melted plastic.

[0006] EP 1 972 424 B1 discloses the bonding of a plastic rivet to an elongated hole by changing the shape of the plastic rivet, for example by means of ultrasonic deformation, at the elongated hole in such a way that an undercut is created with the elongated hole.

[0007] CN 101 852 223 A discloses a first component with openings arranged in a recess of the first component. A second component is inserted into the recess, wherein the second component has rivet columns that protrude through the openings. The rivet columns are flattened, so that the second component is connected to the first component.

[0008] US 2007 158 011 A1 discloses a method for joining two components, wherein a resin column formed on one of the components, which protrudes through an opening in the other component, is melted by means of an ultrasonic welding device, so that it mushrooms under the application of pressure by the ultrasonic welding device and provides a positive connection between the components. BRIEF DESCRIPTION OF THE INVENTION

[0009] The invention is therefore based on the object of providing an arrangement of two components which are connected to one another by means of a rivet mandrel formed on one of the components, wherein a load on the rivet connection in the event of overload is reduced by allowing the rivet to deflect, but at the same time inhibiting the penetration of rivet material into a through-opening for the rivet mandrel when the rivet head is formed by hot riveting and also enabling a reliable fit of the further component with respect to the component during normal operation.

[0010] The object is solved by the features of independent claim 1. Advantageous further developments and preferred embodiments form the subject matter of the subclaims.

[0011] A component, in particular a support part, is designed such that at least one further component, in particular a cladding part, can be fastened to the component by riveting, in particular hot riveting, using at least one rivet mandrel formed on the further component. In an arrangement according to the invention, in which the component and the further component are riveted to one another, the rivet mandrel forms a rivet head when it is guided through a through-opening formed in the component and a projecting end of the rivet mandrel is deformed. The through-opening is formed in a weakened region of the component, wherein the weakened region has a lower breaking load than the adjacent region of the component and a lower breaking load than the formed rivet. In particular, the component, with the exception of the rivet mandrel, is arranged outside the weakened region.The weakened area allows the rivet to deflect in the area of ​​the weakened area during overload. At the same time, an open slot is avoided, preventing the molten material of the rivet mandrel from penetrating during riveting. Under normal load, the through hole provides a reliable hold for the rivet.

[0012] The other component is made of a thermoplastic material.

[0013] For this purpose, the arrangement, in particular the weakened area, has one or more of the following features a)-e): a) The weakened area has a groove which is formed in a surface of the component facing the other component, wherein the through-opening is formed in a groove base of the groove which has a slit in a longitudinal direction of the weakened area, and a width of the slit is less than an outer diameter of the rivet mandrel. The slit can serve as a through-opening and can have a width which is less than an outer diameter of the rivet mandrel. With a suitable choice of material and dimensioning, the groove base folds away when the rivet mandrel is pushed through. The elongated slit can compensate for distortion in such a way that manufacturing tolerances can be compensated for or kept less tight, since the insertion point of the rivet mandrel no longer needs to be defined so precisely. b) The weakened area is at least partially perforated. Perforation could, for example, consist of a large number of small through holes that penetrate and weaken the component. c) The weakened area has a slotted hole filled with a foamy and / or porous material. Foam can also allow the rivet to deflect under overload. Instead of a slotted hole, the foam can also be molded directly into certain areas during component manufacturing. d) The weakened area has a width which is designed in such a way that it tapers in a / the longitudinal direction of the weakened area in order to enable a braking effect when the rivet deflects in the event of an overload.

[0014] If the weakened area has a surface on a side facing away from the other component that is flush with a surface of the component adjacent to the weakened area, the rivet head of the formed rivet can also bear on the adjacent surface of the component, i.e., in an area of ​​the component that is not weakened. This can provide reliable resistance to the riveting tool and can also ensure a stable rivet connection.

[0015] The remaining material thickness of the component at the groove base is preferably approximately 5% to 15%, preferably approximately 7% to 13%, in particular approximately 10% of the material thickness of the component in the area adjacent to the weakened area. These thickness ratios can also ensure sufficient resistance for the riveting tool, sufficient grip under normal load, and sufficient weakening under overload. These values ​​can be modified depending on the material selection or material pairing of the component and other components.

[0016] Specifically, the remaining material thickness at the groove base is preferably approximately 0.2 mm to 0.5 mm, preferably approximately 0.25 mm to 0.35 mm. It goes without saying that these values ​​are also scalable depending on the component thickness and material.

[0017] The weakened region may have a width that is equal to or greater than an outer diameter of the rivet mandrel and preferably smaller than an outer diameter of the formed rivet head.

[0018] The weakened area can further have a curved shape in a plane with a normal vector that is substantially parallel to the direction in which the rivet mandrel passes through the through-hole. This allows the rivet to be guided along any desired path.

[0019] The rivet mandrel can have a hollow space open at one end, with the rivet head being formed by a tool that extends at least partially into the hollow space. This allows, for example, centering of the tool or heating of the rivet mandrel from the inside.

[0020] An aspect not belonging to the invention is a method for riveting, in particular by means of hot riveting, a component to at least one further component, wherein a rivet mandrel formed on the further component is guided through a through-opening formed in the component and a projecting end of the rivet mandrel is deformed in order to form a rivet head. According to the invention, the through-opening is or is formed in a weakened region of the component and the weakened region is or is formed such that it has a lower breaking load than the adjacent region of the component and a lower breaking load than the formed rivet. The weakened region can be created before, during or after the formation of the through-opening.

[0021] In embodiments of the method, the rivet head of the further component is formed by thermal deformation, wherein - the protruding end of the rivet mandrel is at least partially melted, - the melted end is compressed against the surface of the weakened area, and - the melted end is then allowed to solidify.

[0022] Preferably, in the method, the above-described component or the above-described arrangement of the component and the further component is formed or used to rivet the component to the further component. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention is described below with reference to the accompanying drawings, in which: Fig. 1 a cross-sectional view of a component and another component in a positioned state prior to connection according to an embodiment of the invention; Fig. 2 a sectional view along a line II-II in the direction of the corresponding arrows in Fig. 1; Fig. 3 a cross-sectional view of a component and another component in the connected state according to another embodiment of the invention; Fig. 4 a plan view in the direction of an arrow IV in Fig. 3; Fig. 5 a cross-sectional view of a component and another component in the connected state according to another embodiment of the invention; Fig. 6 a cross-sectional view of a component and another component in the connected state according to another embodiment of the invention; Fig. 7A to 7E Design variants of a component for attaching another component with a rivet mandrel in a sectioned bottom view; Fig. 8A and Fig. 8B Cross-sectional views of a component and another component in a positioned state and in a connected state, respectively; Fig. 9 a cross-sectional view of a component for attaching another component with a rivet mandrel according to another embodiment of the invention; Fig. 10 a plan view in the direction of an arrow XI in Fig. 9; Fig. 11 is a cross-sectional view of a component for attaching a further component with a rivet mandrel according to a further embodiment of the invention; and Fig. 12 a cross-sectional view of a component for attaching another component with a rivet mandrel according to another embodiment of the invention.

[0024] The figures are intended to illustrate the features essential to the invention and are therefore purely schematic and may be shown not to scale and / or exaggerated in one direction compared to another. DETAILED DESCRIPTION OF EXAMPLES OF WORKING MODELS

[0025] The invention is described below with reference to exemplary embodiments and with additional reference to the drawings.

[0026] A component 1 is, for example, a carrier part and is prepared for the attachment of another component 2, which is, for example, a cladding or decorative part. Fig. 1 shows a cross-sectional view of the component 1 and the further component 2 in a positioned state before connecting the components according to an embodiment of the invention, and Fig. 2 shows a sectional view of the component 1 with positioned rivet mandrel 10 from below along a line II-II in Fig. 1 in the direction of the corresponding arrows.

[0027] For connection by hot riveting (also called weld riveting or welding), the additional component 2 carries a rivet mandrel 10, which points toward the component 1 during assembly, and the component 1 has a through-opening 11 for the passage of the rivet mandrel 10. The rivet mandrel 10 has a cavity 12 at its distal end, which is intended to accommodate or center a melting and / or forming tool. The cavity 12 is optional; for example, it can provide centering for the tool and / or a depth stop when forming the rivet head 30, or even enable heating of the rivet mandrel 10 from the inside.

[0028] The through-opening 11 is formed within a weakened region 13 of the component 1. The weakened region 13 can be formed in a variety of ways, as will be explained below with reference to this and several other exemplary embodiments. The through-opening 11 can also be formed in a variety of ways.

[0029] In this exemplary embodiment, the weakened region 13 is designed as an elongated recess or groove 14, which is formed in the surface of the component 1 on the side facing the further component 2. On the side facing away from the component 2, i.e. on the side on which the rivet mandrel 10 protrudes through the component 1 when the further component 2 is positioned for connection, a certain component thickness is retained, which is also referred to as a membrane 15. The membrane 15 has a surface 16 that is flush with the surface in the adjacent region of the component 1. The feedthrough opening 11 is designed in this exemplary embodiment as a through-hole with a circular or substantially circular cross-section.

[0030] The rivet mandrel 10 has an outer diameter da and, in the region of the cavity 12, an inner diameter di. The diameters da and di can be average values, since both the outer surface of the rivet mandrel 10 and the inner surface of the cavity 12 can be conical. The component 1 has a component thickness T. The weakened region 13 has a length L and a width W. The length L is greater than the width W. The membrane 15 has a thickness t. The feedthrough opening 11 has a diameter D that is equal to or smaller than the width W of the weakened region 13 and greater than or equal to the outer diameter da of the rivet mandrel 10.

[0031] In the automotive sector, in which component 1 is, for example, a carrier part and the further component 2 is, for example, a trim or decorative part, component thicknesses T of approximately 2.3 mm to 3.5 mm are common. However, this is purely exemplary and does not limit the invention in any way. The thickness t of the membrane 15 is limited on the lower side by the manufacturability of the membrane 15 in the tool and the temperature stability of the carrier material (component 1) compared to the melting range of the decorative part (further component 2). An upper limit can, for example, result from the condition that the rivet should move in the event of an overload, i.e. the membrane 15 should then yield. These conditions will result in suitable wall thicknesses for each application, depending on the material pairing and dimensions of the workpieces.

[0032] To connect component 1 and the further component 2, the rivet mandrel 10 is inserted through the through-hole 11, and the distal end of the rivet mandrel 10 is compressed and formed by a tool – possibly with melting. The thus connected component 1 and further component 2 form a fixed assembly. Fig. 3, component 1 and the further component 2 are shown in the connected state. Fig. 4 shows the same arrangement in a plan view in the direction of arrow IV in Fig. 3. It is noted that Fig. 3 the composite is cut in the longitudinal direction of the weakened area 13, that is to say in section along a line III-III in the direction of the corresponding arrows in Fig. 4 shows.

[0033] After completing the connection process described above, the rivet mandrel has moved into the area of ​​the feed-through opening (in Fig. 3 not shown) to a rivet shank 31 and now fills the entire width of the weakened area, while a rivet head 30 has formed on the surface 16 of the component 1. The extent of the expansion of the rivet mandrel depends on the circumstances and can also be less.

[0034] As in Fig. 1, the membrane 15 has a thickness t. The membrane thickness t is dimensioned such that the membrane 15 remains intact during the connection process, but yields in the event of an overload of the connection, for example, during an impact, so that the rivet shaft 31 can deflect in the longitudinal direction of the groove 14, partially destroying the membrane 15. In other words, the weakened area 13 has a lower breaking load than the adjacent area of ​​the component 1. In addition, the weakened area 13 has a lower breaking load than the formed rivet (rivet mandrel 31, rivet head 30). Therefore, a residual strength of the connection can be maintained even in the event of overload and yielding of the connection. Thus, the weakened area 13 acts like an elongated hole in the event of an overload, but offers a tighter fit under normal load and also prevents the material of the rivet mandrel 10 from flowing into the feedthrough opening 11 during the riveting / connecting process.

[0035] Fig. 5 shows in a cross-sectional view corresponding Fig. 3 shows the connection state of the component 1 and the further component 2 in an embodiment in which the rivet mandrel does not have a cavity 12 (in Fig. 3).

[0036] Fig. 6 shows in a cross-sectional view corresponding Fig. 3 shows the connection state of component 1 and the further component 2 in an embodiment in which the rivet shank 31 does not fill the groove 14 to its full width after the connection process (also for a rivet mandrel that does not have a hollow space). This means that a piece of the membrane 15 remains below the rivet head 30 even in the width direction of the groove 14.

[0037] Fig. 7A to 7E show in respective bottom views, which correspond to the view in Fig. 2, design variants of the component 1 for attaching at least one further component 2. In all cases, the weakened area 13 is designed as a groove 14 with a membrane 15.

[0038] In the version according to Fig. 7A, the diameter D of the through-hole 11 essentially corresponds to the width W of the groove 14 and is slightly larger than the outer diameter d a of the rivet mandrel 10. The through-hole 11 is formed approximately in the middle of the groove 14 in the longitudinal direction. In the event of an overload, the rivet shank 31 can deflect in both directions along the groove 14.

[0039] In the version according to Fig. 7B, the groove 14 is conical, i.e., with a continuously decreasing width. The through-hole 11 is located at the wide end of the groove 14. In the event of an overload, the rivet shank 31 can deflect toward the narrower end of the groove 14. Thus, the side walls of the tapered groove 14 act as a comparatively soft brake for the rivet shank 31.

[0040] In the version according to Fig. 7C, the through-hole 11 is designed as a slot in the longitudinal direction of the groove 14. The membrane 15 is designed to be so flexible that the rivet mandrel 10, when pierced, bulges or folds away the edges of the membrane 15, as shown for example in Fig. 8A. During the connection, the forming rivet head 30 compresses the edges of the membrane 15, which at the transition point between the rivet head 30 and the rivet shaft 31 can even be surrounded by the material of the rivet mandrel 11 and thus can be enclosed by the finished rivet, as shown for example in Fig. 8B shown. Fig. 8A and Fig. 8B are cross-sectional views corresponding to Fig. 6. This slit also creates a distortion compensation, which allows positioning of the rivet mandrel 10 with large tolerances.

[0041] In the version according to Fig. 7D, which is a further development of the variant of Fig. 7C, the through-opening 11 is designed as a slot in the longitudinal direction of the groove 14 with two relief slots 11', which run transversely at the ends. In this variant, the above-described and in Fig. 8A, Fig. The flap effect shown in Figure 8B is further improved.

[0042] In the version according to Fig. 7E, which is a further development of the variant of Fig. 7C, the through-opening 11, which is formed as a slot in the longitudinal direction of the groove 14, has a curvature along a curvature line 70, so that in the event of an overload the rivet shank 31 can follow the curvature line 70.

[0043] Fig. 9 is a cross-sectional view of a component 1 according to a further embodiment of the invention, and Fig. 11 is a plan view in the direction of an arrow XI in Fig. 10. In this embodiment, the weakened region 13 is designed such that a perforation in the form of a plurality of small through holes 100 is provided in the component.

[0044] As in Fig. 11 as a further development of the embodiment of Fig. 9 and Fig. 10 in a cross-sectional view according to Fig. 9, in the case of the perforation 100, the groove 14 can also be additionally provided, so that the perforation 100 is formed in the membrane 15 left by the groove 14.

[0045] In another embodiment, which is shown in Fig. 12 in a cross-sectional view according to Fig. As shown in Figure 9, the weakened region 13 has a continuous elongated hole 130 filled with a foam 131. Alternatively, the foam 131 can also be manufactured in one piece with the component 1 during the manufacturing process of the component 1 by appropriate process control in a single operation. As an alternative to the foam 131, a porous or otherwise flexible material can also be used.

[0046] Above, exemplary embodiments of the invention have been described in detail with reference to the accompanying figures, including several variants and options. It is understood that the exemplary embodiments and variants or options described above can all be combined with one another, unless this is obviously prohibited. LIST OF REFERENCE SYMBOLS 1 component (supporting part) 2 Additional component (cladding part) 11 Through hole (through hole or slot) 10 rivet mandrel 12 Cavity 13 Weakening area 14 Recess (slot or groove) 15 Membran 16 Surface 30 rivet head 31 rivet shank 70 Curvature line 100 perforations 130 slot 131 filling because outer diameter of rivet mandrel the inner diameter of the rivet mandrel t wall thickness membrane D Diameter of the feedthrough opening L Length of weakening area T Wall thickness component W Width of weakening area

Claims

[1] An arrangement comprising a component (1) and a further component (2) which are connected to one another by riveting by means of at least one rivet mandrel (10) formed on the further component (2), wherein the rivet mandrel (10), when guided through a through-opening (11) formed in the component (1) and a projecting end of the rivet mandrel (10) is deformed, forms a rivet head (30), wherein the through-opening (11) is formed in a weakened region (13) of the component (1) which has a lower breaking load than the adjacent region of the component (1) and a lower breaking load than the formed rivet, wherein the further component (2) is made of a thermoplastic material, characterized by one or more of the following characteristics: - the weakened region (13) has a groove (14) which is formed in a surface of the component (1) facing the further component (2), wherein the through-opening (11) is formed in a groove base of the groove (14) which has a slit in a longitudinal direction of the weakened region (13), and a width of the slit is smaller than an outer diameter of the rivet mandrel (10); - the weakened area (13) is at least partially perforated; - the weakened area (13) has an elongated hole (130) filled with a foamy and / or porous material (131); - the weakened region (13) has a width (W) which is designed such that it tapers in a longitudinal direction of the weakened region (13). [2] Arrangement according to claim 1, wherein the weakened region (13) has, on a side facing away from the further component (2), a surface (16) which is flush with a surface of the component (1) adjacent to the weakened region (13). [3] Arrangement according to claim 1 or 2, wherein a remaining material thickness of the component (1) at the groove base is approximately 5% to 15%, preferably approximately 7% to 13%, in particular approximately 10% of the material thickness of the component (1) in the area adjacent to the weakened area (13). [4] Arrangement according to one of the preceding claims, wherein, if the weakened region (13) has the groove (14), a remaining material thickness at the groove base is approximately 0.2 mm to 0.5 mm, preferably approximately 0.25 mm to 0.35 mm. [5] Arrangement according to one of the preceding claims, wherein the weakened region (13) has a width (W) which is equal to or greater than an outer diameter (da) of the rivet mandrel (10) and preferably smaller than an outer diameter of the formed rivet head. [6] Arrangement according to one of the preceding claims, wherein the weakened region (13) has a curved shape in a plane with a normal vector which is substantially parallel to a direction of passage of the rivet mandrel (10) through the passage opening (11). [7] Arrangement according to one of the preceding claims, wherein the rivet mandrel (10) has a cavity (12) open at one end, wherein the rivet head (30) is formed by means of a tool projecting into the cavity (12).

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