Method for adjusting the actual preload force of a headlight seal

Abstract

The invention relates to a method for adjusting an actual preload force of a headlight seal (1), in which - the headlight seal (1) is manufactured in a plastic injection molding tool with at least one fixing contour (3), a sealing contour (7) and an externally arranged hanging tab (2) with a bracket (6), - the headlight seal (1) is connected to a headlight cover (4) with the fixing contour (3) and is pulled over a retaining contour (5) on the headlight cover (4) with its hook tab (2), - the actual preload force of the headlight seal (1) is recorded and compared with a target preload force, - if the actual preload is below the target preload, the plastic injection molding tool is adapted in such a way that a minimum distance (a) of the bracket (6) of the mounting tab (2) to the sealing contour (7) of the headlight seal (1) is reduced and thereby the actual preload of headlight seals (1) produced in this way is increased.

Description

[0001] The present invention relates to a method for adjusting the actual preload force of a headlight seal. The invention further relates to a headlight seal manufactured according to this method, and to a headlight comprising a housing and a headlight cover connected thereto via such a headlight seal. The present invention further relates to a motor vehicle with such a headlight.

[0002] From DE 10 2017 006 439 A1, a vehicle front fairing with at least one headlight is known, wherein the vehicle front fairing comprises a fairing panel with an outer and an inner surface and is predominantly opaque when viewed from the outside. The fairing panel has at least one seamless, translucent area, wherein a headlight for illuminating an area in front of the vehicle is arranged on the inner surface of the fairing panel. Furthermore, the headlight has a headlight housing that is sealed against the inner surface of the fairing panel and has a C-channel with a seal inserted therein. At least one rib is provided on the fairing panel, which is inserted into the C-channel and rests against the seal.

[0003] From EP 4 339 413 A1, a seal for fastening in or to a door opening and for interaction with a second seal installed in a door leaf is known. The first seal has a fastening part and a sealing part for aligning with a sealing profile of the second seal. Furthermore, the first seal has at least one elastic part by means of which movement of the sealing part of the first seal relative to the fastening part of the first seal is permitted. In addition, the seal has at least one adjusting element by which the distance and / or the alignment of the sealing part to the fastening part can be adjusted. This individual element is designed as a screw.

[0004] Headlight covers (lenses) on motor vehicles are typically sealed to the surrounding trim panels using a headlight gasket to minimize the ingress of wind and dirt into the engine compartment or cavities behind it. This function can only be guaranteed by ideal positioning and dimensional stability. To ensure a proper seal, the headlight gasket must be positioned between the headlight cover and the headlight housing with a predefined fit and tension.

[0005] In order to adjust, for example, the fit or preload of such a headlight seal, a plastic injection mold must be adapted accordingly, often requiring several iteration loops with repeated adjustments of the plastic injection mold, which is not only complex but also time-consuming and expensive.

[0006] The present invention therefore deals with the problem of providing a method by which previously necessary, complex and expensive iteration processes for adapting a headlight seal can be avoided, or at least reduced.

[0007] This problem is solved according to the invention by the subject matter of independent claim 1. Advantageous embodiments are the subject matter of the dependent claims.

[0008] The present invention is based on the general concept of providing an individually adjustable point on a headlight seal that is extremely easy to adapt using tooling techniques. This allows for a relatively simple modification of a plastic injection mold at this point, enabling the preload force, specifically the actual preload force, of the headlight seal to be adjusted relatively easily, thereby achieving a reliable seal between a headlight cover and a headlight housing. In the inventive method for adjusting the actual preload force of the headlight seal, the headlight seal is first produced in a plastic injection mold with at least one sealing contour, a corresponding edge-side mounting tab, and a fixing contour. The produced headlight seal is then connected to a headlight cover via the fixing contour or multiple fixing contours.The fixing contours are attached to the headlight cover. The headlight seal, with its mounting tab, is then pulled over a retaining contour on the headlight cover, thereby pre-tensioning the seal. This retaining contour can be, for example, a corresponding tab over which the mounting tab of the headlight seal is pulled and secured by engaging behind the retaining contour. The actual pre-tension of the headlight seal is then measured and compared to a target pre-tension defined for optimal sealing. If the actual pre-tension is below the target pre-tension, the plastic injection mold is adjusted to reduce the minimum distance between the mounting tab's bracket and the sealing contour of the headlight seal, thereby increasing the actual pre-tension of the resulting headlight seal.If the actual preload force exceeds the target preload force, the plastic injection mold is adjusted to increase the minimum distance between the retaining tab's bracket and the sealing contour of the headlight seal, thereby reducing the actual preload force. The headlight seal can, for example, be a type of ring seal with the retaining tab molded onto it, projecting outwards. There is an opening between the retaining tab and the sealing contour of the headlight seal, through which the retaining tab is pulled over the retaining contour on the headlight cover side. If, during the manufacturing of the headlight seal, the distance between the retaining tab (or a bracket of this retaining tab) and the headlight seal is increased, i.e.,If the sealing contour of the headlight seal is reduced, a greater force must be applied to engage the mounting tab on the retaining contour in order to pull the bracket of the mounting tab, and thus the mounting tab itself, over the retaining contour on the headlight cover side. This increased pulling force when pulling the mounting tab over the retaining contour on the headlight cover side simultaneously exerts a greater preload force on the headlight seal, thereby increasing the actual preload force of such a headlight seal. By a relatively simple variation of the minimum distance between the bracket of the mounting tab and the sealing contour of the headlight seal, the actual preload force of the headlight seal can be influenced relatively easily, without requiring a complex and expensive modification of a plastic injection mold. At the same time, the minimum distance between the mounting tab and the...a bracket of the mounting tab and the sealing contour of the headlight seal in direct relation to an actual preload force when the headlight seal is applied to the headlight cover, so that, for example, if a measured actual preload force is below a predefined target preload force, for example based on a table, a corresponding reduction of the minimum distance of the bracket of the mounting tab to the sealing contour of the headlight seal can be taken and set on the plastic injection molding tool, whereupon the next headlight seal produced with this plastic injection molding tool already has the desired actual preload force.

[0009] In an advantageous further development of the method according to the invention, the headlight seal is manufactured as a two-component injection-molded plastic part with a soft component in the area of ​​the mounting tab and a hard component in the area of ​​the fixing contour. Such a two-component injection-molded plastic part makes it possible to enforce a predefined shape via the hard component, while the actual sealing function is fulfilled via the soft component. Such two-component injection-molded plastic parts can be manufactured simply and cost-effectively.

[0010] In an advantageous further development of the method according to the invention, an elastomer is used as the soft component. Such an elastomer is rubber-elastic and elastically deformable, thereby achieving a desired sealing effect compared to a rigid plastic. Examples include, in particular, styrene-butadiene rubber (SBR), nitrile rubber (NBR), but also, for example, ethylene propylene diene monomer rubber (EPDM).

[0011] In an advantageous further development of the method according to the invention, glass fiber reinforced polypropylene (PP-GF) is used as the hard component. Polypropylene possesses high resistance, is waterproof, and also resists mold and bacteria, which is particularly advantageous in areas exposed to moisture, such as the headlights of a motor vehicle. Due to the glass fiber reinforcement of the polypropylene, the hard component has significantly increased strength without a substantial increase in weight or material usage.

[0012] The hard component is conveniently placed in the plastic injection mold, and the soft component is then injection-molded onto the hard component within the mold. There are essentially two different approaches: one involves placing a pre-fabricated hard component, perhaps containing glass fibers, into the mold and then injecting the soft component onto it. Alternatively, it is also possible to inject or produce both the hard and soft components simultaneously within the mold. In all these methods, a strong bond is created between the soft and hard components.

[0013] The present invention is further based on the general concept of providing a headlight seal manufactured according to the inventive method as described in the preceding paragraphs. This allows the advantages described for the inventive method to be transferred to the headlight seal according to the invention. Specifically, these advantages lie in a comparatively simple and therefore not only manufacturing-friendly but also cost-effective adjustment of the actual preload force of the headlight seal to a target preload force. With the inventive method, the unit costs of the manufactured headlight seal can thus be significantly reduced, since the inventive method eliminates a large number of previously required and complex iteration steps for adjusting the actual preload force.

[0014] In an advantageous embodiment of the headlight seal according to the invention, the bracket of the mounting tab is integrally connected to the sealing contour of the headlight seal via two webs. The bracket can run parallel to the headlight seal or its sealing contour on the western side and have a bulge that is dependent on a desired actual preload force and directed towards the sealing contour of the headlight seal. The minimum distance of the bracket of the mounting tab to the sealing contour is adjusted by the size / thickness of this bulge, and thus indirectly also the actual preload force of such a headlight seal.

[0015] In an advantageous embodiment of the headlight seal according to the invention, the bracket has a base strip. Such a base strip is formed integrally with the bracket and also integrally with the entire headlight seal and is essentially wedge-shaped in cross-section, which allows it to engage behind the retaining contour on the headlight cover side particularly reliably.

[0016] The present invention is further based on the general concept of providing a headlight with a headlight housing and a headlight cover connected to it via a headlight seal as described in the preceding paragraphs. The major advantage of such a headlight lies particularly in the comparatively low unit costs of the headlight seal, since the inventive method for adjusting the actual preload force of the headlight seal no longer requires several expensive interaction steps, as was previously necessary.

[0017] The present invention is further based on the general concept of equipping a motor vehicle with a headlight described in the previous paragraph, thereby transferring the advantages described with respect to the headlight according to the invention to the motor vehicle. Specifically, these advantages consist of a reliable seal between a headlight cover and a headlight housing, while simultaneously reducing the unit costs for the headlight seal used, which also has a positive effect on the manufacturing costs of the motor vehicle according to the invention.

[0018] Further important features and advantages of the invention will become apparent from the dependent claims, the drawings and the associated description of the figures based on the drawings.

[0019] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention as defined by the claims. Components of a higher-level unit, such as a device, apparatus, or arrangement, mentioned above and those to be mentioned below, which are designated separately, can form separate parts or components of this unit or be integral areas or sections of this unit, even if this is depicted differently in the drawings.

[0020] Preferred embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein identical reference numerals refer to identical or similar or functionally identical components.

[0021] They show, schematically, Fig. 1 Individual process steps of a method according to the invention for adjusting an actual preload force of a headlight seal, Fig. 2 a headlight seal according to the invention stretched over a headlight cover, Fig. 3 a detailed representation from Fig. 2, Fig. 4 a sectional view through a headlight according to the invention in the area of ​​a mounting tab of a headlight seal according to the invention, Fig. 5 a detailed representation of the headlight seal according to the invention in the area of ​​the mounting tab, Fig. 6 a representation as in Fig. 5, however, with a reduced minimum distance between the bracket of the mounting tab and a sealing contour of the headlight seal, Fig. 7 a representation as in Fig. 6, however with a further reduced minimum distance between the bracket of the mounting tab and the sealing contour of the headlight seal.

[0022] According to the Fig. 1 discloses a method according to the invention for adjusting an actual preload force of a headlight seal 1 (compare the Fig. 2 - 7) a total of four process steps A to D, wherein in a first process step A the headlight seal 1 is formed in a plastic injection molding tool with at least one edge-side hanging tab 2 with a bracket 6 and with a fixing contour 3 (compare Fig. 3) is manufactured. In process step B, the headlight seal 1 with the fixing contour 3 is connected to a headlight cover 4 and pulled over a retaining contour 5 on the headlight cover 4 with its mounting tab 2, thereby lengthening and pre-tensioning the headlight seal 1. In process step C, the actual pre-tension force (tensile force) present in the headlight seal 1 or in a sealing contour of the headlight seal 1 after its assembly on the headlight cover 4 is measured and compared with a predefined target pre-tension force. In process step D, if the actual pre-tension force is below the predefined target pre-tension force, i.e., if the headlight seal 1 is too loose, the plastic injection mold is adjusted so that a minimum distance a (compare the Fig. 5 - 7) of a bracket 6 of the mounting tab 2 to the sealing contour 7 of the headlight seal 1 is reduced, thereby increasing the actual preload force of a headlight seal 1 produced in this way. Alternatively, if the actual preload force is above the predefined target preload force, it is conceivable to adapt the plastic injection molding tool such that a minimum distance a of the bracket of the mounting tab 2 to the sealing contour 7 of the headlight seal 1 is increased, thereby reducing the actual preload force of a headlight seal 1 produced in this way.

[0023] It is of course clear that the sealing contour 7 does not have to be a completely closed ring, but can also simply be a ring segment that runs between two fixing contours 3.

[0024] The method according to the invention thus significantly reduces the countless iteration steps previously required to set the correct and desired actual preload force, since the minimum distance a between the mounting tab 2 and the sealing contour 7 of the headlight seal 1, i.e., specifically between the bracket 6 of the mounting tab 2 and the sealing contour 7 of the headlight seal 1, is a measure of the actual preload force of the headlight seal 1. The smaller the distance a, the greater the tensile force required to pull the mounting tab 2 over the retaining contour 5 on the headlight cover side, and the greater the actual preload force introduced into the headlight seal 1.

[0025] The mounting tab 2 has the aforementioned bracket 6, which is integrally connected to the headlight seal 1 or the sealing contour 7 of the headlight seal 1 via two webs 8. This bracket 6 runs according to the Fig. 2 - 7 essentially parallel to the headlight seal 1 or parallel to the sealing contour 7 of the headlight seal 1 and has a bulge 9 which depends on a desired actual preload and is directed towards the headlight seal 1 or the sealing contour 7 of the headlight seal 1. The "thicker" this bulge 9 is, the smaller the minimum distance a between the bulge 9, i.e. the bracket 6 of the mounting tab 2 and the sealing contour 7 of the headlight seal 1, and the greater the actual preload force introduced into the headlight seal 1 or the sealing contour 7.

[0026] If one examines the bracket 6 of the hanging tab 2 more closely, one can see that this is a footboard 10 (compare the Fig. 4 and Fig.5) has a feature by which it reliably engages the retaining contour 5 on the headlight cover side. A surface of the bracket 6 or the base 10 facing the retaining contour 5 is designed to be complementary to a surface of the retaining contour 5 facing the bracket 6 or the base 10 of the mounting tab 2.

[0027] Furthermore, the headlight seal 1 can be manufactured as a 2K injection-molded plastic part with a soft component 11 in the area of ​​the mounting tab 2 and a hard component 12 in the area of ​​the fixing contour 3. For example, an elastomer can be used as the soft component, which allows for elastic, rubber-like deformation. In contrast, polypropylene, in particular fiber-reinforced, preferably glass fiber-reinforced, polypropylene (PP-GF), can be used as the hard component 12. Such fiber-reinforced polypropylene enables high strength of the hard component 12 while maintaining low weight.

[0028] The hard component 12 and the soft component 11 can be joined in a plastic injection mold, whereby the hard component 12 is first inserted into the plastic injection mold and then the soft component 11 is injection-molded onto the hard component 12 in the plastic injection mold. Alternatively, it is also conceivable that both the soft component 11 and the hard component 12 are produced in a single plastic injection molding process.

[0029] In summary, the inventive method allows the actual preload force of a headlight seal 1 to be set relatively easily and quickly, without requiring major modifications to a plastic injection mold. This allows the headlight seal 1 to be adapted relatively quickly with regard to its fit and the target preload force required for optimal sealing, so that the reduced iteration steps generally result in lower unit costs for the headlight seal 1.

[0030] The headlight seal 1 according to the invention is used in a headlight 13 to seal the headlight cover 4 against a housing not described in detail. Such a headlight 13 is used in a motor vehicle 14, in particular in an electric vehicle. This allows the advantages described with regard to the method according to the invention to be transferred not only to the headlight seal 1 according to the invention, but also to the headlight 13 according to the invention and the motor vehicle 14 according to the invention. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2017 006 439 A1

[0002] EP 4 339 413 A1

[0003]

Claims

[1] Method for adjusting an actual preload force of a headlight seal (1), wherein - the headlight seal (1) is manufactured in a plastic injection molding tool with at least one fixing contour (3), a sealing contour (7) and an externally arranged hanging tab (2) with a bracket (6), - the headlight seal (1) is connected to a headlight cover (4) with the fixing contour (3) and is pulled over a retaining contour (5) on the headlight cover (4) with its hook tab (2) and thereby pre-tensions the headlight seal (1), - the actual preload force of the headlight seal (1) is recorded and compared with a target preload force, - if the actual preload is below the target preload, the plastic injection molding tool is adjusted in such a way that a minimum distance (a) of the bracket (6) of the mounting tab (2) to the sealing contour (7) of the headlight seal (1) is reduced and the actual preload is thereby increased, or if the actual preload is above the target preload, the plastic injection molding tool is adjusted in such a way that a minimum distance (a) of the bracket (6) of the mounting tab (2) to the sealing contour (7) of the headlight seal (1) is increased and the actual preload is thereby reduced. [2] Method according to claim 1, characterized by , that the headlight seal (1) is manufactured as a 2K plastic injection molded part with a soft component (11) in the area of ​​the mounting tab (2) and a hard component (12) in the area of ​​the fixing contour (3). [3] Method according to claim 2, characterized by , that an elastomer is used as the soft component (11). [4] Method according to claim 2 or 3, characterized by , that glass fiber reinforced polypropylene (PP-GF) is used as the hard component (12). [5] Method according to any one of claims 2 to 4, characterized by , that the hard component (12) is placed in the plastic injection molding tool and the soft component (11) is injected onto the hard component (12) in the plastic injection molding tool. [6] Headlight seal (1), manufactured according to the method of any of the preceding claims. [7] Headlight seal (1) according to claim 6, characterized by , that the bracket (6) of the mounting tab (2) is connected to the sealing contour (7) of the headlight seal (1) via two webs (8). [8] Headlight seal according to claim 6 or 7, characterized by, that the bracket (6) runs essentially parallel to the sealing contour (7) of the headlight seal (1) and has a bulge (9) which depends on a desired actual preload force and is directed towards the sealing contour (7) of the headlight seal (1). [9] Headlight seal (1) according to claim 7 or 8, characterized by , that the bracket (6) has a baseboard (10). [10] Headlight (13) with a housing and a headlight cover (4) connected thereto via a headlight seal (1) according to one of claims 6 to 9. [11] Motor vehicle (14) with a headlight (13) according to claim 10.

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