Method for manufacturing an aerodynamic panel for a rim

Abstract

Method for manufacturing an aerodynamic aperture (10) for a rim (1), comprising the following steps, Inserting at least one mounting bushing into an injection mold, Injection molding of a base body (11) of the aero diaphragm (10) from a first material in the injection molding tool, wherein the mounting bushing forms a mounting section (13) of the aero diaphragm (10) in the base body (11), Applying a seal (12) to the base body (11) made of a second material, wherein the seal (12) has at least a first sealing section (121) and at least a second sealing section (122), Painting the base body (11).

Description

[0001] The present invention relates to methods for manufacturing an aerodynamic grille for a rim, in particular a motor vehicle.

[0002] To increase the energy efficiency of vehicles, aerodynamic aspects are a particular focus of development work. For example, various types of rims with aerodynamically optimized shapes are known from the prior art. Some of these also use fairings arranged on the outside of the rim. Within the scope of the invention, the outside of the rim is understood to be the axial side of the rim facing away from the vehicle. This side therefore points away from the vehicle when the rim is mounted.

[0003] Document WO 2019 060 173 A1 discloses a four-part wheel trim, the individual parts of which are clipped together and connected to a rim. A seal made of a thermoplastic elastomer is arranged around the outer edge, bearing against the rim. Document WO 2013 026 880 A1 discloses a plastic trim that is screwed to a rim structure. For the purposes of this application, the term "rim structure" refers to the load-bearing component of the wheel. This component comprises a hub, to which the wheel is attached to the wheel suspension of a vehicle, and spokes that extend radially from the wheel hub and have the rim well at their other outer end, around which the tire is arranged. The rim well is the radially circumferential part of the rim and can be described geometrically, in simplified terms, as a hollow cylinder.The rim bed also features rim shoulders, which are located at the axial ends of the rim bed and accommodate the tire between them. These can be understood as projections of the hollow cylinder, extending radially from the axial ends of the hollow cylinder. The rim shoulder, which is located on the outside of the rim structure / rim, can project axially beyond the spokes. The rim structure is typically made of a lightweight metal or a composite material, for example, with carbon fibers, and according to the prior art, can also constitute a rim on its own.

[0004] Document DE 20 2018 000 319 U1 discloses a plastic cover for screwing onto a rim. The rim has LED light guides. A seal is provided between these and the cover. Document WO 2015 106 760 A1 discloses a plastic cover that is screwed to a rim. A seal is arranged on the rim bed. Patent document EP 3 401 118 A1 describes a wheel whose components are screwed together and sealed with a gasket. Document DE 10 2012 107 692 A1 discloses a wheel cover that is bonded to a rim body via a connecting strip. Document WO 2015 019 119 A1 discloses a housing for use, for example, with bicycle wheels. The housing has two shells that are sealed, for example, welded. A seal is arranged at an opening of the housing. The document further reveals a rim of a motor vehicle, on the visible side of which a cover is arranged.

[0005] Furthermore, patent documents DE 10 2019 101 654 A1, DE 10 2019 101 666 A1, DE 10 2011 107 064 B4, DE 19 804 776 A1, DE 10 2011 079 599 B4 and DE 10 2012 208 081 B4 disclose plastic covers for a wheel rim. These plastic covers partially feature a seal on the back, which at least partially seals them against the rim. In addition, various methods for attaching the plastic cover to the rim are disclosed. More precise details regarding a method used to manufacture such covers are not provided in the aforementioned patent documents.

[0006] Against the background described above and the prior art mentioned and described with regard to different rims, the object of the present invention is to provide a method for manufacturing an aerodynamic panel for a rim of a vehicle.

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

[0008] An aerodynamic cover for a rim, produced according to the inventive method, comprises a base body designed to cover a gap between two spokes of a rim structure, and a seal. The gap is defined as the space between two, in particular adjacent, spokes in the circumferential direction. The seal, in turn, comprises a first sealing section and a second sealing section, wherein the first sealing section is designed to seal at least a portion of a gap between the base body and a spoke of the rim structure, and the second sealing section is designed to seal at least a portion of a gap between the base body and a rim bed of the rim structure. Preferably, several first and second sealing sections may be provided.

[0009] An aerodynamic cover produced by this process is designed to be positioned between two spokes of a rim structure, at least partially covering the space between the spokes. This reduces air turbulence during the rim's rotation around the hub, thereby lowering the vehicle's overall drag. The two-part construction, consisting of a robust, load-bearing rim structure and an aerodynamic cover, allows for a rim with the same aerodynamic properties as a comparable rim made from a monolithic structure (where both the rim structure and the aerodynamic cover are made of the same durable material), while saving weight. The seals acoustically decouple the base body from the rim structure, thus improving comfort for the vehicle occupants.The seal also ensures a consistent gap between the rim structure and the aerodynamic cover, enabling the cover to self-center and position itself relative to the rim. Furthermore, the seals prevent foreign objects such as pebbles or contaminants from passing through the gap between the aerodynamic cover and the rim structure, thus protecting components like the wheel suspension and brakes. Additionally, the seals prevent contaminants that might enter the gap between the cover and wheel from the inside of the rim via the brake cooling air duct from accumulating or becoming lodged there, thus preventing any visual obstruction.

[0010] The inventive method for manufacturing an aerodynamic cover for a rim comprises several steps. First, a mounting bushing is inserted into an injection mold. For the purposes of this application, a mounting bushing is understood to be an element made of a different, in particular more heat-resistant, material than the base body of the aerodynamic cover. The element is designed such that a connection can be established between the mounting bushing and a corresponding counterpart for attaching the aerodynamic cover to the rim. The mounting bushing is, in particular, designed as a brass bushing with an internal thread into which a corresponding screw can be screwed, so that the aerodynamic cover can be attached to the rim by means of the screw connection. Inserting the mounting bushing also includes holding the mounting bushing in a specific position. For this purpose, appropriate geometries can be provided in the mold.

[0011] In a further process step, a base body of the aerodynamic cover is injection-molded from a first material in the injection mold, with the mounting bushing forming a mounting section of the aerodynamic cover. This process is specifically described as an insert molding process, in which the mounting bushing is fixed as an insert within the base body by the injection molding process. Once the mounting bushing is formed in the base body after the injection molding of the first material, the mounting section is complete. Preferably, a plastic, in particular a polyphthalamide-based plastic such as PA9T, is used as the first material. This ensures a particularly lightweight aerodynamic cover and reduces the weight of the rim. Furthermore, such materials exhibit positive properties with regard to thermal and chemical influences.

[0012] Furthermore, in a further process step, a seal made of a second material is applied to the base body, wherein the seal comprises at least a first sealing section and at least a second sealing section. The sealing sections are preferably interconnected. The second material preferably exhibits elasticity and is thus flexibly deformable, making it particularly suitable for achieving a sealing effect between the rim and the aerodynamic cover. Thermoplastic elastomers (TPE) are particularly preferred. The first sealing section is a section of the seal which, in the mounted state of the aerodynamic cover, seals it against a spoke of the rim, while the second sealing section is a section of the seal which, in the mounted state of the aerodynamic cover, seals it against a circumferential rim bed, preferably against the outer rim flange.

[0013] In a further process step, the base body is painted. Depending on the embodiment, this painting can take place before or after the application of the seal. Preferably, the painting is carried out by applying three layers (3-layer structure). This manufacturing process provides a simple method for producing an aerodynamic fairing for a rim, in which, in particular, a mounting section designed for attachment can be easily incorporated.

[0014] In an advantageous embodiment of the method according to the invention, the process step for applying the seal takes place while the base body is in the injection mold for overmolding. This allows both the application of the seal and the overmolding of the base body to be carried out in the same mold, which in particular saves the effort and time required for changing the mold. The machining machine or the mold therefore does not need to be changed between the two steps.

[0015] Preferably, after the injection molding of the base body, the injection mold moves from a first position, where the injection molding took place, to a second position, where the seal is applied. This movement particularly includes a rotation, preferably 180°. Thus, the mold can be moved to a different position, where further processing, for example, by a second injector, can be carried out to apply the seal. Changing the position of the mold and base body is simpler than changing the machine used for injection molding the base body or for applying the seal.In an alternative embodiment, between the injection molding of the base body and the application of the seal, the base body is ejected from the injection mold in which the injection molding took place and picked up by another mold for applying the seal. Thus, unlike the embodiment described above, the machining—i.e., the creation of the base body and the application of the seal—takes place in two different machines. This ensures cooling times between the machining steps and increases the cycle rate of the individual work steps, particularly when longer cooling times between work steps are required.

[0016] In a further advantageous embodiment of the invention, the seal is applied by a compression molding process, in particular a compression molding process. In such a process, a specific volume of material corresponding to the element to be manufactured is placed in a mold, which is then sealed under pressure in a press. The pressure and elevated temperature deform the material, and the mold is filled with the vulcanized material.

[0017] Other processes are also conceivable, such as injection molding, in particular compression transfer molding or injection transfer molding. Likewise, prefabricated sealing elements can be attached to the base body.

[0018] A further advantageous embodiment of the method for manufacturing an aerodynamic vent is one in which the seal is applied to the inner side of the base body. The inner side is the side of the base body that faces the vehicle when installed. The outer side, therefore, faces away from the vehicle and is the side that is visible when installed. Alternatively, it is also conceivable that the seal is applied to the edge of the vent and is thus located neither on the inner nor the outer side. Applying the seal to the inner side has the advantage that it is better protected from direct mechanical impact or exposure to sunlight and therefore does not wear out as quickly.Furthermore, applying the seal to the inside is advantageous due to the greater space available compared to applying it to the edge / border area, as this allows for more complex seal geometries. The seal is preferably made of a thermoplastic elastomer. Such seals are easy to process and exhibit sufficiently high flexibility and sealing properties.

[0019] In a preferred embodiment of an aerodynamic flap, the base body is injection-molded with at least one aerodynamic guide element, which is designed in particular such that the airflow exerts a force on the aerodynamic flap directed in such a way that the aerodynamic flap is pressed axially against the rim structure. This reduces the load on the fastening element used to attach the aerodynamic flap, such as a screw or a positive-locking clip connection, when the flap is mounted, and significantly reduces the risk of unintentional separation of the aerodynamic flap and the rim structure.

[0020] In a further advantageous embodiment of the invention, the seal is applied such that it has at least one spacer element. A spacer element is understood to be an element that defines the distance between the rim structure and the base body. In the correctly mounted state, it rests on a corresponding counter-element, such as a support, of the rim structure, thus ensuring the correct positioning of the aerodynamic cover or the correct distance between the base body and the rim structure. Preferably, such an element can be arranged, for example, in the seal and, in particular, preferably has the same material as the seal itself. Therefore, it can be easily incorporated into the manufacturing process of the seal and requires no additional manufacturing effort.

[0021] Advantageous aspects and embodiments of the invention are explained in more detail below with reference to the accompanying figures. The figures show: Fig. 1a the outer side of a rim 1 with an aerodynamic diffuser 10 produced by the inventive method. Fig. 1b the inside of the in Fig. Rim 1 shown in 1a in a slightly perspective view. Fig. 2 the inside of an aero-diaphragm 10 produced by the inventive method.

[0022] Fig. Figure 1a shows the outer side of a rim 1 with an aerodynamic cover 10 produced by the inventive method. The rim 1 consists of five aerodynamic covers 10 according to the invention and a rim structure 20. This, in turn, has a hub 24 around which corresponding holes are provided for attaching the rim 1 to a wheel suspension of a vehicle. Starting from the hub 24, five double spokes, i.e., five pairs of parallel spokes 21, extend radially outwards and terminate in a rim bed 22. The rim bed 22 can be understood, in geometric approximation, as a hollow cylinder onto which a tire can be mounted. The spokes 21 are arranged at the front of the rim 1 and thus on the side facing away from the vehicle when the rim 1 is mounted. It is also conceivable to consider embodiments of the rim in which the spokes 21 are arranged offset to the rear within the rim bed 22.

[0023] Between the pairs of spokes 21, spaces are provided in the circumferential direction of the rim 1, which are approximately shaped like a slice of cake. These spaces are partially covered by the aerodynamic skirts 10. The aerodynamic skirts 10 thus extend from one spoke 21 of a spoke pair to a spoke 21 of an adjacent spoke pair. They also have an aerodynamic guide element 14, which is designed to guide the airflow during the rotation of the rim in such a way as to minimize air turbulence. Furthermore, the shape of the guide elements 14 generates a force that is directed such that the aerodynamic skirts 10 are pressed against the rim structure 20. This improves the attachment of the aerodynamic skirts 10 to the rim structure 20. In this embodiment, the guide element 24 is to be understood as a specifically shaped, i.e., non-planar, surface of the base body 11.Of course, other forms of aerodynamic panels 10 and rim structures 20 are also conceivable. The ones in the . Fig. 1a and Fig. The embodiment shown in 1b serves only as an example.

[0024] Fig. 1b shows the in Fig. Figure 1a shows the rim 1 in a perspective view from the rear. From this view, the shape of the rim bed 22 is more clearly visible, which can be geometrically simplified and described as a hollow cylinder. The aerodynamic fairings 10 are each connected to the rim structure 20 by three screw connections. These connections are made via supports 23, which extend from the rim bed 22 and the spokes 21.

[0025] One embodiment of the aerosol aperture 10 that can be produced by the method according to the invention is described with regard to Fig. 2 explained in more detail. The illustrated embodiment of the aerodynamic cover 10 is shown from the inside of the rim 1, as it is also shown in Fig. 1b is shown. The aerodynamic cover 10 has a base body 11 on which a seal 12 and three cylindrical mounting sections 13 are arranged. The mounting sections 13 are arranged such that they can rest on the supports 23 of the rim structure 20 in the assembled state (see Fig. 1b) In the embodiment shown, the fastening sections 13 have fastening bushings in the form of threaded inserts, so that screws can be screwed from the inside of the rim 1 through the supports 23 into the threaded inserts and thus into the fastening sections 13 to ensure the fastening of the aero panel 10 to the rim structure 20.

[0026] The seal 12 has two first sealing sections 121 and a second sealing section 122, wherein the first sealing section 121 is configured to seal a gap between the base body and the spoke 21, and the second sealing section 122 is configured to seal a gap between the base body 11 and the rim bed 22. In the illustrated embodiment, a gap between the base body 11 and the outer horn of the rim structure, which is to be understood as part of the rim bed, is sealed. The function of the sealing sections is described with regard to the Fig. 3a and Fig.3b explained in more detail. The seal 12 thus seals the gap between the rim structure 20 and the base body 11 of the aerodynamic cover 10, whereby the aerodynamic cover 10 does not cover the entire space between the adjacent pairs of spokes 21. Consequently, a sealing effect can only be provided at the points where the aerodynamic cover 10 is in contact with the rim structure 20.

[0027] Furthermore, additional spacer elements 123 are provided on the aerodynamic flap 10, which in the illustrated embodiment are formed as part of the seal 12. These further ensure the positioning of the aerodynamic flap 10 in relation to the rim structure 20. It is also conceivable to use embodiments of the invention in which no spacer elements 123 are provided.

[0028] The seal 12 is preferably made of a thermoplastic elastomer. The base body 11 can, for example, be made of a lightweight plastic, such as a polyphthalamide-based plastic, and / or a fiber-reinforced composite material, in order to minimize the weight of the rim 1. Because the aerodynamic cover 10 and the rim structure 20 are two separate components that are connected to each other via appropriate fasteners, it is possible to design the aerodynamic cover 10 with a significantly lower weight than comparable monolithic rims, where both the aerodynamic cover 10 and the rim structure 20 are manufactured from a single component.

[0029] According to the inventive method for manufacturing the aerodynamic diffuser 10, the mounting bushings are first inserted into an injection mold and then overmolded by injecting a first material, in particular PA9T, thus forming the base body 11 by an injection molding process. The insertion of the mounting bushings is preferably automated. The mounting bushings form the mounting sections 13. The seal 12 is then applied to the base body 11.

[0030] Depending on the embodiment of the process, the base body can either remain in the injection mold or in the half of the injection mold in which it was formed, whereby the injection mold is moved to another processing station within the same machine, in particular rotated by 180 degrees. In this other processing station, the seal 12 is applied to the back of the base body 11, which in this embodiment is freely accessible in the injection mold. For this, for example, an injection molding process or a compression molding process is used.

[0031] Alternatively, the base body 11 is ejected from the injection mold and transferred to another mold, where it can cool down. The seal 12, preferably made of a thermoplastic elastomer, is then applied in the other mold.

[0032] Finally, or depending on the embodiment, before applying the seal 12, a coating is applied using a high-temperature coating system, in particular with a 3-layer structure.

Claims

[1] Method for manufacturing an aerodynamic aperture (10) for a rim (1), comprising the following steps, Inserting at least one mounting bushing into an injection mold, Injection molding of a base body (11) of the aero diaphragm (10) from a first material in the injection molding tool, wherein the mounting bushing forms a mounting section (13) of the aero diaphragm (10) in the base body (11), Applying a seal (12) to the base body (11) made of a second material, wherein the seal (12) has at least a first sealing section (121) and at least a second sealing section (122), Painting the base body (11). [2] Method according to the preceding claim, wherein the method step for applying the seal (12) is carried out while the base body (11) is in the injection molding tool for injection molding the base body (11). [3] Method according to the preceding claim 2, wherein the injection molding tool moves, in particular rotates, from a first position, in which the injection molding of the base body (11) has taken place, to a second position, in which the application of the seal (12) takes place, after the injection molding of the base body (11). [4] Method according to the preceding claim 1, wherein between the injection molding of the base body (11) and the application of the seal (12) the base body (11) is ejected from the injection molding tool in which the injection molding of the base body (11) has taken place and is received by another tool for applying the seal (12). [5] Method according to one of the preceding claims, wherein the application of a seal (12) is carried out by a compression molding process, in particular a compression molding process. [6] Method according to one of the preceding claims, wherein the painting is carried out by applying three layers of paint.

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