Fastening clip and method for mounting a seal

Abstract

Fastening clip for fastening a component (11) to a carrier (12), comprising a locking element (14) which can be locked in an opening (26) of the carrier (12) by means of at least two locking arms (20), and a spreading element (16) which can be adjusted relative to the locking element (14) between a pre-assembly position in which the locking arms (20) are in a pre-assembly position and a fastening position in which the locking arms (20) are spread so that the locking element (14) is locked to the carrier (12), wherein the locking element (14) is provided with a seal (18) and the locking element (14) has a support plate (30) on which the seal (18) is placed, and wherein the locking element (14) supports the seal (18) in the axial direction (A) on a radius (r1) which essentially corresponds to the radius (r2) of a principal contact area (60) with which the seal (18) rests against the support (12),wherein the seal (18) extends over an outer circumferential edge (32) of the support plate by means of a skirt (46), wherein the skirt (46) has a width (b) which is at least 10% of the maximum diameter (d) of the seal (18) and wherein an inner circumferential edge (48) of the skirt (46) is spaced away from the support plate (30) in the pre-assembly position.

Description

[0001] The invention relates to a fastening clip for attaching a component to a carrier, in particular for attaching a door or wall panel to a body part of a motor vehicle.

[0002] Such fastening clips are usually composed of several elements, including a locking element which, by means of locking arms, can engage an opening in the carrier to secure the fastening clip, and an expanding element which is adjustable relative to the locking element between a pre-assembly position and a fastening position and which can cause the locking arms to lock. It is also known to provide a seal which seals the opening in the carrier part and which, in particular, prevents the ingress of dirt and water through the opening into the interior of the carrier.

[0003] Similar fastening clips are known from WO 2013 / 114303 A1, FR 1464727 A, US 5846040 A, DE 102011050216 A1, EP 1403533 A1, or US 2008 / 0219758 A1. Further information can be found in DE 102013200689 A1 and GB 2360322 A.

[0004] The object of the invention is to create a fastening clip that achieves a good seal over a long period of time, especially with simple manufacturing and modular adaptability.

[0005] To solve this problem, the features of claim 1 are provided according to the invention. The fastening clip for attaching a component to a carrier has a locking element that can be locked in an opening of the carrier by means of at least two locking arms, and a spreading element that can be adjusted relative to the locking element between a pre-assembly position, in which the locking arms are in a pre-assembly position, and a fastening position, in which the locking arms are spread such that the locking element is locked onto the carrier. The locking element is provided with a seal. The locking element has a support plate onto which the seal is placed, the locking element supporting the seal axially on a radius that essentially corresponds to the radius of a principal contact area with which the seal bears against the carrier.The main contact area corresponds to the section of the seal that first comes into contact with the carrier when the mounting clip is inserted into the opening. This area of ​​the seal is essentially identical to the area of ​​the seal that experiences the greatest contact force in the mounting position and is therefore primarily responsible for the sealing effect of the seal with respect to the opening in the carrier.

[0006] The support plate assists the seal in the mounting position, thus exerting an axial force towards the carrier at the point where the sealing effect primarily occurs. Therefore, the sealing effect can be maintained to a high degree over a long period, particularly throughout the entire service life of the mounting clip.

[0007] According to the invention, the seal is not injection-molded onto the locking element, but is a separate, prefabricated component, distinct from both the locking element and the carrier plate, which is placed onto the carrier plate. This design allows the mounting clip to be used modularly. For example, different seals for various applications, such as those made of different materials or with different dimensions, can be mounted on an otherwise identical locking element. In this way, materials that cannot be processed together in a two-component injection molding process, for example, can be used for both the seal and the carrier plate.

[0008] Due to the modular design of the mounting clip, identical locking elements and seals can be used across customers for different applications, such as mounting on various vehicle types, while only the expanding element is customized. Since a separate tool is required to manufacture each of the individual components of the mounting clip—the locking element, the seal, and the expanding element—tooling costs can be reduced. As described above, locking elements and seals can be prefabricated with different dimensions, such as diameter and thickness, and made from different materials, and then combined with the respective customer-specific expanding element to create the finished mounting clip.

[0009] Furthermore, this makes it possible to easily replace a seal or expanding element before installation, if necessary.

[0010] Preferably, the seal rests against the support with substantially the same contact force over its entire circumference defined by the radius. For this purpose, the support plate is advantageously designed to be continuous along the circumference defined by this radius.

[0011] To more precisely define the main contact area and to generate a uniform contact force, the main contact area of ​​the seal can be provided with a bead facing the substrate, which forms the essential contact between the seal and the substrate. While it is of course possible for other areas of the seal to also rest on the substrate in the installed position, circumferential contact of the main contact area is usually sufficient to achieve an adequate seal.

[0012] To provide a supporting contact force over a long period, the carrier plate preferably has a frustoconical shape. The opening angle is directed towards the carrier, so that, in particular, an outer circumferential edge of the carrier plate presses axially against the seal, with the outer circumferential edge of the carrier plate bearing against the seal on the opposite side of the bead of the main contact area. Viewed axially, the outer circumferential edge of the carrier plate and the main contact area of ​​the seal are thus aligned.

[0013] The opening angle of the truncated cone of the support plate preferably increases during the transition from the pre-assembly position to the mounting position, thereby increasing the preload force on the seal. However, the shape of the support plate should only change during the transition to the mounting position to such an extent that the support plate retains a certain degree of elasticity in order to provide sufficient preload force on the seal to maintain an adequate seal even in the long term and even if the seal's elasticity decreases.

[0014] Preferably, the seal rests against the outer circumferential edge of the carrier plate with elastic preload and, in particular, surrounds the outer circumferential edge. This allows the seal to be easily and securely fixed to the carrier plate, while the preload simultaneously enables more precise positioning of the main contact area relative to the carrier plate. On the side of the carrier plate facing away from the carrier, the seal preferably rests flat against the plate, which further supports precise positioning.

[0015] According to the invention, the seal extends over the outer circumferential edge by means of a skirt, the skirt being able to have a width that is at least 10% of the maximum diameter of the seal. The skirt extends radially inwards, so that the large width of the skirt creates a deep recess in which the outer circumferential edge of the support plate is held securely against displacement.

[0016] In the installed position, when the mounting clip is attached to the carrier, the skirt can rest fully or partially on the carrier. However, the primary sealing effect is always provided by the main contact area of ​​the seal, which can be located at the radially outer end of the skirt and thus close to the radial outer circumference of the seal. Since the carrier plate sits in the recess formed by the skirt, the outer circumferential edge of the carrier plate is also located close to the outer circumference of the seal.

[0017] Since, according to the invention, an inner circumferential edge of the apron is spaced away from the carrier plate in the pre-assembly position, the remaining gap can be used to simplify the automated placement of the seal onto the carrier plate.

[0018] The apron is preferably provided with a bead on its inner circumferential edge on the side facing the support plate, which, for example, increases the stability of the apron.

[0019] To ensure a complete seal of the opening, the seal preferably has a through-opening whose inner circumferential edge rests against the expanding element. This allows the transition to a shaft of the expanding element protruding through the opening to be sealed. The inner circumferential edge of the through-opening can be provided with a bead that, particularly in the installed position, engages in a groove on the shaft of the expanding element to enhance the sealing effect.

[0020] Since the seal and the backing plate are two separate components, it is easy to manufacture them from different materials. In one advantageous material pairing, the seal consists of a thermoplastic elastomer (TPE) and the backing plate of polyoxymethylene (POM). This allows the seal to be made from a significantly more elastic and flexible material, while the backing plate can be made from a material with high long-term stability, ensuring sufficient contact pressure on the seal even after years of installation in a vehicle. Other advantageous material pairings are at the discretion of the person skilled in the art.

[0021] The invention also relates to a method for mounting a seal onto a carrier plate of a fastening clip, as described above. The seal is expanded by a gripper and placed over the carrier plate. This allows the fastening clip to be easily manufactured automatically without excessive forces acting on the seal, while ensuring fast and precise positioning of the seal on the carrier plate.

[0022] The invention is described in more detail below with reference to an exemplary embodiment and the accompanying drawings. The drawings show: - Fig. 1 a schematic exploded view of a fastening clip according to the invention; - Fig. 2 a schematic sectional view of the fastening clip according to the invention in the fastening position, mounted on a support; - Fig. 3 a schematic exploded view of the locking element and the seal of the fastening clip according to the invention; - Fig. 4 a schematic sectional view through the seal of the fastening clip according to the invention; - Fig. 5 a schematic sectional view through the locking element with the seal of the fastening clip according to the invention mounted thereon; and - Fig. 6 an enlarged section from Fig. 5.

[0023] The figures show a fastening clip 10, which serves to fix a component 11 (not specified in detail here) to a support 12 (see Fig. 2) The component is, for example, a door panel, while the carrier 12 can be a body part of a motor vehicle.

[0024] The fastening clip 10 consists of a locking element 14, a spreading element 16, a seal 18 which is arranged on the locking element 14, and a cap 19 which is fixed to a tip of the spreading element 16 at the end of the manufacturing of the fastening clip 10.

[0025] The locking element 14 has two opposing locking arms 20, which can be spread apart radially. An opening 22 is formed between the locking arms 20, through which a shaft 24 of the spreading element 16 is inserted.

[0026] The fastening clip 10 can assume a pre-assembly position in which the locking arms 20 are also in a pre-assembly position, in which they are not yet spread apart and can be pushed through an opening 26 in the carrier 12. Furthermore, the fastening clip 10 can assume a fastening position in which the shaft 24 of the spreading element 16 is pushed further between the locking arms 20 through the opening 26, and the locking arms 20 are spread apart so that they engage behind the edge of the opening 26 in the carrier 12 and lock the fastening clip 10 onto the carrier 12 (see Fig. 2).

[0027] The component 11 to be fastened can be fixed at an upper end 28 of the spreading element 16.

[0028] The locking element 14 comprises a carrier plate 30, from which the locking arms 20 project in the axial direction A. The carrier plate 30 has a truncated conical shape, with the truncated cone opening towards the locking arms 20 and, in the assembled state, towards the carrier 12. The carrier plate 30 is completely closed and has a free outer circumferential edge 32.

[0029] The seal 18 has an upper cover section 34 with a central opening 36 through which the shaft 24 of the expanding element 16 projects. The inner circumferential edge 38 of the opening 36 is formed as a bead 40. In the fastening position, the bead 40 engages in a groove 42 in the shaft 24 of the expanding element 16.

[0030] At the radially outer edge of the cover section 34, a circumferential edge section 44 extending essentially in the axial direction A is provided, which transitions into a radially inwardly extending skirt 46. The skirt 46 terminates at a radially inner circumferential edge 48, on which a bead 50 is formed, directed towards the interior of the seal 18 and, in the assembled state, towards the support plate 30.

[0031] In this example, the apron 46 has a width b in the radial direction which is at least 10%, in particular about 10 to 20%, of the total diameter d of the seal 18.

[0032] The inner circumferential edge 48 of the apron 46 including the bead 50 is spaced in the pre-assembly position by a certain gap 51 from an underside of the carrier plate 30, which is directed towards the locking arms 20.

[0033] In this embodiment, the assembly of the fastening clip 10 is automated. A gripper (not shown) with multiple arms grasps the space between the skirt 46 and the cover section 34 and spreads the seal 18 radially apart, thus expanding the seal 18. In this state, the seal 18 is placed over the carrier plate 30 of the locking element 14, with the carrier plate 30 coming to rest between the skirt 46 and the cover section 34. The gripper is then retracted. Finally, the spreading element 16 is pushed through the opening 36 of the seal 18 and the opening 22 between the locking arms 20 into a pre-assembly position in which the locking arms 20 are not yet spread apart. Finally, the cap 19 is placed onto the free tip of the spreading element 16.

[0034] For mounting on the carrier 12, the fastening clip 10 is first inserted through the opening 26 in this pre-assembly position and then the spreading element 16 is pushed further into the carrier part 12 in axial direction A relative to the locking element 14, thereby spreading the locking arms 20 apart until the fastening clip 10 has reached its fastening position and is fixed on the carrier 12.

[0035] In the pre-assembly position, the outer circumferential edge 32 of the carrier plate 30 lies in a receptacle 52, which is formed at the transition of the skirt 46 to the edge section 44 of the seal 18.

[0036] The area 54 of the cover section 34 adjoining the edge section 44 follows the shape of the truncated cone of the support plate 30, so that it lies flat against an outer surface 56 of the support plate 30. The outer circumferential edge 32 of the support plate 30 is thus enclosed by the seal 18.

[0037] In the axial direction A, on the side of the skirt 46 facing the support 12, below the circumferential edge 32 of the support plate 30, lies a bead 58 that defines a main contact area 60 of the seal 18. The main contact area 60 first comes into contact with the support 12 when the fastening clip 10 is inserted into the opening 26. Furthermore, the highest contact force is permanently exerted here, and the main contact area 60 provides the primary sealing effect against the opening 26 in the support 12.

[0038] The bead 58 is located in the radially outer section of the seal 18 and can connect directly radially inside to the edge section 44.

[0039] Due to the flat contact of the area 54 of the seal 18 with the carrier plate 30 and the firm seating of the outer circumferential edge 32 of the carrier plate 30 in the receptacle 52, the bead 58 is largely positionally fixed with respect to the outer circumferential edge 32.

[0040] During the transition from the assembly position to the fastening position, the relative position between the bead 58 and the outer circumferential edge 32 does not change significantly, even if the support plate 30 is forced apart to a certain extent, thus increasing the opening angle of the truncated cone. This deformation creates a preload on the skirt 46 and, in particular, on the bead 58 of the seal 18, resulting in a uniform, long-lasting contact force on the main contact area 60 of the seal 18.

[0041] Even in the fixed position, the outer circumferential edge 32 of the support plate 30 and the bead 58 of the skirt 46 of the seal 18 lie at least substantially on top of each other in the axial direction A. Therefore, the support plate 30 supports the seal 18 on a radius r1, which essentially coincides with a radius r2 on which the bead 58 and thus the main contact area 60 lies.

[0042] In this example, the seal 18 is made of a thermoplastic elastomer (TPE), while the locking element 14 and in particular the support plate 30 are made of polyoxymethylene (POM).

Claims

[1] Fastening clip for fastening a component (11) to a carrier (12), comprising a locking element (14) which can be locked in an opening (26) of the carrier (12) by means of at least two locking arms (20), and a spreading element (16) which can be adjusted relative to the locking element (14) between a pre-assembly position in which the locking arms (20) are in a pre-assembly position and a fastening position in which the locking arms (20) are spread so that the locking element (14) is locked to the carrier (12), wherein the locking element (14) is provided with a seal (18) and the locking element (14) has a support plate (30) on which the seal (18) is placed, and wherein the locking element (14) supports the seal (18) in the axial direction (A) on a radius (r1) which is substantially the radius (r2) of a principal contact area (60). corresponds to the seal (18) resting against the support (12),wherein the seal (18) extends over an outer circumferential edge (32) of the support plate by means of a skirt (46), wherein the skirt (46) has a width (b) which is at least 10% of the maximum diameter (d) of the seal (18) and wherein an inner circumferential edge (48) of the skirt (46) is spaced away from the support plate (30) in the pre-assembly position. [2] Fastening clip according to claim 1, characterized by , that the main installation area (60) of the seal (18) is provided with a bead (58). [3] Fastening clip according to any one of the preceding claims, characterized by , that the support plate (30) has a truncated cone shape. [4] Fastening clip according to any one of the preceding claims, characterized by , that the seal (18) rests against the outer circumferential edge (32) of the support plate (30) with elastic preload. [5] Fastening clip according to any one of the preceding claims, characterized by, that the apron (46) is provided with a bead (50) on its inner circumferential edge (48) on the side facing the support plate (30). [6] Fastening clip according to any one of the preceding claims, characterized by , that the seal (18) has a through opening (36) whose inner circumferential edge (38) rests against the spreading element (16). [7] Fastening clip according to any one of the preceding claims, characterized by , that the seal (18) is made of a thermoplastic elastomer (TPE) and the support plate (30) is made of polyoxymethylene (POM). [8] Method for mounting a seal (18) on a carrier plate (30) of a fastening clip (10) according to one of the preceding claims, wherein the seal (18) is expanded by a gripper and slipped over the carrier plate (30).

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