Fastening arrangement for attaching a component to a support

Abstract

Fastening arrangement for attaching an airbag gas generator (1) to a carrier element (5) of a vehicle, comprising at least one fastening element (9, 11) which has, on the side of the carrier element facing the airbag gas generator (1), a head part (31) to which the airbag gas generator (1) can be attached, and a shaft part (33) which passes through a mounting opening (37) of the carrier element (5) and engages behind an opening edge (53) on the side of the carrier element facing away from the airbag gas generator (1), wherein the fastening element (9, 11) has a base body (35) made of plastic in which at least one metal insert (34) is integrated, and wherein the fastening element head part (31) has a passage (19) through which a mounting aid (21) for attaching the airbag gas generator (1) to the head part (31) is guided, characterized in thatthat an electrical ground connection is made between the airbag gas generator (1) and the carrier element (5) via the fastening element (9), that the fastening element (9) has a scratch or scrape contour (29) for electrical contact which is pressed against the carrier element (5), and that the scratch or scrape contour (29) is formed by a metal insert section exposed by the plastic, which provides an electrical connection between the carrier element (5), the metal insert (34), the electrically conductive mounting aid (21) and the gas generator (1).

Description

[0001] The invention relates to a fastening arrangement for attaching a gas generator for a head airbag to a vehicle-side support element, i.e. a vehicle body structure, according to the preamble of claim 1, and to a fastening element for such a fastening arrangement.

[0002] The gas generator of a vehicle airbag, particularly a head airbag, is typically mounted to the vehicle's body shell using screws. This installation is therefore associated with a high component count and significant manufacturing effort. For example, DE 10 2011 005 081 A1 discloses an airbag housing with an integrated generator structure, in which a diffuser cap associated with the gas generator is screwed to an airbag housing made of a fiber-reinforced plastic material.

[0003] From DE 10 2010 008 158 A1, a fastening arrangement is known in which the component is not mounted to the vehicle-side support element via screw points, but rather is attached using a fastening clip. The fastening clip has a head part to which the component can be fastened, and a shaft part that passes through a mounting opening of the support element and engages behind an opening edge of the support element's mounting opening on the side of the support element facing away from the head part.

[0004] The mounting clip is manufactured from a single piece of metal sheet, stamped and bent. This sheet metal part is a blank in its developed state. Due to the manufacturing process, its cut edges are sharp. Consequently, there is a risk that during airbag deployment, the airbag fabric could come into contact with the cut edges of the sheet metal part and be damaged. To prevent such damage to the airbag fabric, current technologies require the cutting edges of the mounting clip to be rounded off, a complex manufacturing process, or the mounting clip geometry to be designed in such a way as to avoid direct contact with the cut edges.

[0005] A fastening arrangement of this type is known from US 2011 / 0 163 562 A1. Further fastening arrangements are known from DE 10 2010 008 158 A1, US 2008 / 0 084 050 A1, EP 1 884 411 A1 and EP 2 014 520 A1.

[0006] The object of the invention is to provide a fastening arrangement for attaching an airbag gas generator to a vehicle-side support element, in which a reliable connection of the airbag gas generator to the vehicle-side support element is enabled in a simple manner.

[0007] The problem is solved by the features of claim 1. Preferred embodiments of the invention are disclosed in the dependent claims.

[0008] The invention addresses the problem that a fastening element manufactured as a stamped and bent sheet metal part may have sharp cut edges that could damage the airbag fabric during deployment. Against this background, the fastening element according to the invention has a base body made of plastic in which at least one metal insert is integrated. The metal insert can be a stamped and bent sheet metal part and is molded into the plastic material of the fastening element base body using an injection molding process. In this way, the fastening element is designed as a composite element, combining the advantages of both materials. These advantages include, on the one hand, the manufacturing precision and shaping possibilities of plastic parts, and on the other hand, the high strength of metal.For example, the metal insert can incorporate paint scraping features described later. Furthermore, the component mounting, in particular the mounting of an airbag gas generator, to the composite element can be achieved via the metal insert. Conversely, the component, i.e., the gas generator, can be supported on the carrier element by the plastic base of the mounting element. The metal insert can also be used to apply a preload force to at least one connection point on the carrier element, ensuring a rattle-free mounting of the component. Additionally, the plastic base can be used to compensate for tolerances.

[0009] The following are the details of the invention: As mentioned above, in a particular embodiment the component can be an airbag generator. To avoid direct contact between the airbag fabric and the metal insert of the fastening element, the metal insert on the fastening element head can preferably be at least partially encased by the plastic material of the base body. Alternatively or additionally, the metal insert on the fastening element head can have a section exposed by the plastic. However, this section can be set back from the outer contour of the plastic base body by a certain amount to avoid the aforementioned contact between the airbag fabric and the metal insert.

[0010] The exposed metal insert section on the fastener head can, for example, have a positioning contour that enables the component to be placed correctly on the fastener head. Additionally, the fastener head has a passage through which an assembly aid, in particular an ear clamp, is guided. The ear clamp can circumferentially grip the component, in particular the airbag gas generator, and secure it to the fastener. In a particular embodiment, the exposed metal insert section on the fastener head can be spaced apart from a passage base on the base body, forming the passage.

[0011] In a further embodiment, the shaft portion of the fastening element can have at least one elastically adjustable locking leg. In its locking position, the locking leg can engage behind an opening edge of the mounting hole, forming a releasable or non-releasable locking connection. Particularly preferred with regard to strength requirements is the locking leg also being a metal insert section exposed from the fastening element's base body.

[0012] To facilitate easy tool operation of the fastener, the locking arm can have a tool projection that allows the locking arm to be adjusted into a release position by generating an elastic restoring force when a tool is applied. In the release position, the fastener can be removed from the mounting opening of the support element. Preferably, the tool projection of the locking arm can be guided through the mounting opening of the support element in the assembled position and protrude from the mounting opening on the side of the support element facing the component by a first vertical offset. In contrast, the positioning contour mentioned above on the fastener head can project beyond the mounting opening of the support element by a second vertical offset, which is greater than the first vertical offset mentioned above.This creates a clearance between the component and the support element, thus providing easy tool access to the tool attachment of the fastener.

[0013] The locking arm can have at least one laterally positioned guide wall. When the locking arm is elastically adjusted from its locking position to its release position, this guide wall can be engaged in a guide slot formed in the plastic base body. Preferably, the guide wall of the locking arm engages with the guide slot in the base body not only in the release position but also in the locking position. This allows the fastener to have a particularly dimensionally stable body that remains dimensionally stable even when the fastener moves laterally within the mounting opening.

[0014] In a preferred mounting arrangement, the component is an elongated airbag gas generator, particularly for a head airbag. This generator can preferably be attached to a body-in-white support structure of the vehicle at two mounting points spaced apart axially. For this purpose, the gas generator can have a first mounting element (hook element) at the first mounting point, which engages the body-in-white support structure. A second mounting element can be provided at the second mounting point, allowing the gas generator to be snapped into place with the support structure. To achieve a rattle-free mounting of the gas generator, it is preferred that both mounting points are pre-tensioned. For this purpose, the mounting element can have a spring arm, which pre-tensions the locking arm with a predetermined spring force against the side of the support structure facing away from the component.The spring element can preferably be a metal insert section exposed within the plastic material, or it can be integrally formed with the metal insert as a single piece of material and / or as a single sheet metal tab. This ensures rattle-free positioning of the fastening element on the vehicle-side support element. The spring leg presses against the support element side facing the component with a predetermined spring force and preload.

[0015] During installation, the gas generator, with its hook element, is first hooked into a mounting opening at the first attachment point on the vehicle-side support element. The gas generator, together with the pre-mounted second fastening element, is then swung towards the corresponding mounting opening and locked into place.

[0016] The ignition mechanism of the gas generator is integrated into an electrical circuit, allowing for a direct electrical ground connection between the gas generator and the vehicle's support structure (carrier element). This requires a conductive electrical connection between the mounting element and the carrier element. To ensure this, the mounting element has a scratch or paint scraping contour, which is preferably pressed against the carrier element under mechanical preload. The scratch or scraping contour is formed by a metal insert section exposed by the plastic material. This creates an electrical connection between the carrier element, the metal insert, the electrically conductive mounting aid, and the gas generator.To provide this electrical connection, the assembly aid must be electrically conductive and brought into electrical contact with another metal insert section.

[0017] The invention and its advantageous embodiments and further developments, as well as their advantages, are explained in more detail below with reference to the drawings.

[0018] They show: Fig. 1 a vehicle in side view with partial elevation showing the installation position of a head airbag module; Fig. 2 in a side section view a fastening arrangement for connecting an airbag gas generator of the head airbag module to a body-in-white support sheet part; Fig. 3. An enlarged view of the connection point of the gas generator to the support plate part; Fig. 4 to 6 different views of the fastening element for the one in the Fig. 3 connection points shown; Fig. 7 in perspective view the fastening element in isolation; Fig. Figures 8 to 11 show different views of the additional fastening element for attaching the gas generator to the support plate part.

[0019] In the Fig. Figure 1 shows a side view of a motor vehicle with a partial elevation, which has a head airbag module with a gas generator 1 and a head airbag 3 folded, for example, in a roll-fold configuration. The head airbag 3 extends in the longitudinal direction x of the vehicle from the A-pillar to beyond the B-pillar along a roof rail of the vehicle. The gas generator 1 is attached to a body-in-white support sheet 5 in the area of ​​the roof rail. In the Fig. Figure 2 shows a side-sectional view illustrating a fastening arrangement for attaching the gas generator 1 to the support plate part 5. Accordingly, the gas generator 1 is an elongated cylindrical component that is attached to the support plate part 5 at two attachment points A and B, which are spaced apart along the axial direction of the gas generator 1. As described later, the two attachment points A and B are pre-tensioned to prevent, for example, rattling noises during operation. At attachment point A, the gas generator 1 is fastened by means of a first fastening element (hook) 9, which engages the support plate part 5. At attachment point B, the gas generator 1 is snapped into place with the support plate part 5 by means of a second fastening element (fastening clip) 11.Each of the two fastening elements 9, 11 has a head part 31 to which the gas generator 1 is attached, and a shaft part 33 which passes through a mounting opening 37 of the support plate part 5 and engages an opening edge on the side of the support plate part 5 facing away from the gas generator.

[0020] In addition, each of the two fastening elements 9, 11 is manufactured as a composite injection molded part, in which a metallic stamped and bent part is overmolded as a metal insert 34 with a plastic base body 35.

[0021] In the Fig. Figures 8 to 11 show the fastening element 9 for the first connection point A in different views. Accordingly, the first fastening element 9 (hook) has laterally projecting support webs 38 on its head 31, which are supported on the generator-facing side of the support plate part 5 in the assembled position. The support webs 37 are molded into the plastic base body 35 of the fastening element 9. In addition, a hook-shaped abutment section 23 is molded into the plastic base body 35. The abutment section 23 of the fastening element 9 is in the assembled position ( Fig. 2, Fig. 11) through the mounting opening 37 in the support plate part 13, so that it engages the opening edge 53 of the mounting opening 37 on the side of the support plate part 5 facing away from the generator.

[0022] The support bridges 38 and the abutment section 23 are in a vertical direction z ( Fig. 8) of the fastening element 9 spaced apart from each other by an offset dimension which is approximately equal to the material thickness s ( Fig. 11) of the support plate part 5. In the head part 31 of the fastening element 9, a passage 19 is formed through which an ear clamp 21 is guided, which according to the Fig. 2 encompasses the gas generator 1 circumferentially and secures it to the fastening element head 31. For correct positioning of the gas generator 1, the fastening element head 31 has a metal insert section 41 exposed by the plastic material. This section is designed with a positioning contour 17 to ensure correct placement of the gas generator. As can be seen from the Fig. 8 and Fig. As further shown in Figure 10, the metal insert section 41 is spaced apart from a passage base 43 on the base body, forming the opening 19. Furthermore, the metal insert section 41 is set back from the outer contour of the plastic base body 35 by a slight offset Δv to prevent any direct contact between the airbag fabric and the metal insert 34.

[0023] As from the Fig. As further shown in Figures 2, 8 to 9, the metal insert 34 has a further metal insert section 29 exposed by the plastic material. This forms an acute-angled paint scraping contour at the free end of the abutment section 23. The paint scraping contour 29 can be seen in the Fig. In the assembly position shown in Figure 2, a layer of paint penetrates the support plate part 5, thus ensuring electrical contact between the fastening element 9 and the support plate part 5, which may be necessary for an electrical ground connection of the gas generator 1. This provides an electrical connection between the support plate part 5, the metal insert 34, the ear clamp 21, and the gas generator 1.

[0024] At connection part B, in the Fig. 2. The fastening element 11, hereinafter referred to as the fastening clip, is installed. The fastening clip 11 is also manufactured as a composite injection-molded part, also consisting of the head part 31 and the shaft part 33. Analogous to the hook element 9, a passage 19 is defined on the head part between the metal insert section 41 and the passage base 42 of the plastic base body. Additionally, the fastening clip 11 has an elastically adjustable locking arm 45, which engages an opening edge 53 of the mounting opening 37, forming a releasable locking connection. The locking arm 45 is located in the Fig. 2 to 6 are realized as a metal insert section exposed from the plastic material. The fastening clip 11 has support ribs 38 on the generator-facing head part 31 ( Fig. 5) extending over the side of the support plate part 5 facing the gas generator. According to the Fig. 3 A spring arm 47 is provided approximately midway between the two support struts 38, which presses the locking arm 45 against the side of the support plate part 5 facing away from the generator with a predetermined preload force. The spring arm 47 is an integral part of the metal insert 34 and is accordingly realized as a metal insert section exposed from the plastic material.

[0025] For example, from the Fig. 4 and Fig. As further shown in Figure 5, the locking arm 45 has laterally projecting guide walls 57. Upwardly projecting tool projections 49 are formed on the two guide walls 57 of the locking arm 45. The tool projections 49 are in the assembled position according to the Fig. 5 are passed through the mounting opening 37 and project beyond the generator-facing side of the support plate part 5 by a height offset Δh1. When the tool attachments 49 are actuated, the locking arm 45 can be pressed from the shown locking position to a release position (not shown) by building up a return movement, in which the locking connection is released and the fastening clip 11 can be removed from the support plate part 5.

[0026] In the, in the Fig. In the assembly position shown in Figure 5, the positioning contour 17 of the head part 31 projects beyond the support plate part 5 by a second height offset Δh2, which is greater than the first height offset Δh1 of the two tool projections 49. In this way, a disassembly clearance 51 is provided between the gas generator 1 and the support plate part 5 ( Fig. 5) formed in which the tool attachments 49 are easily accessible.

[0027] As from the Fig. 5 and the Fig. As further shown in Figure 7, the plastic base body 35 of the fastening clip 11 has lateral guide slots 55. During an adjustment operation of the locking arm, the two guide walls 57 of the locking arm 45 can immerse themselves in the guide slots 55. In the Fig. 5 The guide walls 57 are designed so that they remain retracted in the guide slots 55 on the base body even in the detent position. In this way, an extremely dimensionally stable body is achieved in the assembled position against lateral movements of the fastening clip 11.

Claims

[1] Fastening arrangement for fastening an airbag gas generator (1) to a carrier element (5) of a vehicle, comprising at least one fastening element (9, 11) which, on the carrier element side facing the airbag gas generator (1), has a head part (31) to which the airbag gas generator (1) can be fastened, and a shaft part (33) which passes through a mounting opening (37) of the carrier element (5) and engages behind an opening edge (53) on the carrier element side facing away from the airbag gas generator (1), wherein the fastening element (9, 11) has a base body (35) made of plastic, in which at least one metal insert (34) is integrated, and wherein the fastening element head part (31) has a passage (19) through which a mounting aid (21) for fastening the airbag gas generator (1) to the head part (31) is guided, characterized bythat an electrical ground connection is made between the airbag gas generator (1) and the carrier element (5) via the fastening element (9), that the fastening element (9) has a scratching or scraping contour (29) for electrical contact, which is pressed against the carrier element (5), and that the scratching or scraping contour (29) is formed by a metal insert section exposed from the plastic, which provides an electrical connection between the carrier element (5), the metal insert (34), the electrically conductive assembly aid (21) and the gas generator (1). [2] Fastening arrangement according to claim 1, characterized byin that, in order to avoid direct contact between an airbag fabric and the metal insert (34) when the airbag is deployed, the metal insert (34) on the head part (31) of the fastening element (9, 11) is at least partially encased by the plastic of the base body (35), or in that the metal insert (34) on the fastening element head part (31) has a section (41) exposed to plastic, which is set back from an outer contour of the base body (34) by an offset dimension (Δv). [3] Fastening arrangement according to claim 2, characterized by that the metal insert section (41) exposed on the fastening element head part (31) has a positioning contour (17) for the correct positional placement of the airbag gas generator (1), and / or that the metal insert section (41) is spaced from a passage base (42) on the base body side, forming the passage (19). [4] Fastening arrangement according to one of the preceding claims, characterized bythat the shaft part (33) of the fastening element (11) has at least one elastically adjustable locking leg (45) which engages behind an opening edge (53) of the mounting opening (37) to form a locking connection, and that in particular the locking leg (45) is a metal insert section exposed from the plastic material of the base body (35). [5] Fastening arrangement according to claim 4, characterized by that the locking leg (45) has a tool attachment (49) which, in the assembled position, is guided through the mounting opening (37) and projects out of the support element mounting opening (37) by a height offset (Δh1) on the support element side facing the airbag gas generator (1). [6] Fastening arrangement according to claim 3 in combination with claim 4 or 5, characterized bythat the positioning contour (17) on the fastening element head part (31) projects beyond the support element mounting opening (37) by a second height offset (Δh2) which is greater than the first height offset (Δh1). [7] Fastening arrangement according to claim 4, 5 or 6, characterized by that the locking leg (45) has at least one laterally offset guide wall (57) which can be retracted into a guide slot (55) in the fastening element base body upon elastic adjustment of the locking leg (45) from a locking position into a release position, and that in particular the guide wall (57) remains at least partially retracted into the base body-side guide slot (55) in the locking position of the locking leg (45). [8] Fastening arrangement according to one of the preceding claims, characterized bythat the metal insert (34) is a metallic stamped and bent part, and / or that the metal insert (34) is cast into the plastic material of the fastening element (9, 11) using a plastic injection molding process.

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