Body structure for a vehicle

Abstract

The invention relates to a body structure for a vehicle, comprising a sheet metal part (5) in which at least one e-coating opening (3) is formed, through which liquid e-coating paint can flow during an e-coating process (I), wherein the e-coating opening (3) can be sealed with a sealing element (1) after the e-coating process (I) has been completed. According to the invention, the sealing element (1) is, in particular, a shapeless sealant that can be applied to the e-coating opening (3) as a liquid sealing material (2) in an application process (II) and can be cured in a subsequent drying process (III).

Description

[0001] The invention relates to a body structure for a vehicle according to the preamble of claim 1, a sheet metal part for such a body structure according to the preamble of claim 8, and a method for manufacturing the body structure according to claim 9.

[0002] In the automotive industry, the e-coating (KTL) process involves dipping the assembled vehicle body with a KTL coating. After dip coating, the KTL coating is transferred to an e-coating oven to thermally cure it. The process then continues with a sealing step, in which the openings in the vehicle body required for the KTL coating process are sealed using rubber plugs or adhesive pads. Finally, a PVC sealing process is carried out, creating a rough seal between sheet metal parts of the body structure and / or forming underbody protection on the vehicle floor.

[0003] Applying the rubber plugs or adhesive pads during the sealing process involves high individual material costs. Furthermore, the rubber plugs in particular are usually inserted manually into the e-coating openings, which is associated with a long production time.

[0004] From DE 10 2011 010 063 A1, a generic body part with at least two adjacent chambers separated by an additional wall is known, wherein a paint drain opening is arranged to connect both chambers and allow excess paint to drain through a common opening. After coating, the opening is sealed with a paste-like seam sealant. This reduces the number of drain openings required and thus the manufacturing and sealing costs.

[0005] DE 10 020 679 A1 discloses a method and a device for sealing joints and seams in motor vehicle bodies using a seam sealant that can be cured by actinic radiation. DE 10159552 A1 discloses a coating mixture for protecting edges and / or seams of metallic substrates. DE 4034725 A1 relates to a PVC-free plastisol composition based on styrene copolymers, plasticizers, and inorganic fillers.

[0006] From DE 10 2020 103 053 A1, a motor vehicle with at least one sound generator is known, which has at least one sound outlet opening associated with a gill-like lamella. From EP 2 135 799 B1, a vehicle structure with asymmetrical paint drain openings is known, which allow excess liquid to drain away during the painting process. After painting, these openings are sealed with special closure pieces.

[0007] The object of the invention is to provide a body structure in which the sealing of the KTL openings is easier to manufacture and / or can be carried out with reduced component effort compared to the prior art.

[0008] The problem is solved by the features of claim 1, claim 8, or claim 9. Preferred embodiments of the invention are disclosed in the dependent claims.

[0009] The invention relates to a vehicle body structure comprising a sheet metal part in which at least one e-coating opening is formed, through which liquid e-coating paint can flow during the e-coating process. After the e-coating process, the e-coating opening can be sealed with a sealing element. According to the invention, the following measure has been taken to simplify the sealing of the e-coating opening from a manufacturing perspective and with reduced component complexity. The sealing element is a shapeless sealant that can be applied to the e-coating opening as a liquid sealant in an application process. The liquid sealant can then be cured in a subsequent drying process. By using the shapeless sealant, the need for a separate sealing element is eliminated, thus reducing material and production costs. The direct application of the sealant also enables automated process integration, thereby eliminating manual assembly steps.Furthermore, the liquid application ensures even distribution and reliable sealing after curing.

[0010] The e-coating (KTL) opening is equipped with a retaining geometry that prevents uncontrolled dripping or flow of the still-liquid sealant during the application process. This retaining geometry ensures a precise seal of the KTL opening. The risk of material loss is minimized, leading to more efficient material utilization and lower production costs. Furthermore, the retaining geometry allows for more precise application and thus improves the quality of the seal.

[0011] The retaining geometry can be formed directly on the sheet metal part in a single piece and / or from a single piece of material. From a manufacturing perspective, it is advantageous if the retaining geometry and the e-coating opening can be formed in a single sheet metal forming process. The retaining geometry is a pocket-shaped embossed contour formed into the sheet metal part. During the application process, the liquid sealant is poured into the pocket-shaped embossed contour in one application direction. The e-coating opening is formed as a slot-shaped gap within the pocket-shaped embossed contour. For example, the pocket-shaped embossed contour can be formed into the sheet metal part during the sheet metal forming process using a forming tool with a stroke-adjustable cutting / embossing die. Manufacturing the retaining geometry and the e-coating opening in a single piece or from a single piece of material ensures robust and cost-effective production.The combined sheet metal forming process eliminates the additional assembly effort required for separate retaining elements. Furthermore, the pocket-shaped embossed contour optimizes the intake and positioning of the sealant, resulting in improved sealing.

[0012] In a specific embodiment, the embossed contour can have at least one embossed contour flank that, viewed in a sheet metal thickness direction, projects from the sheet metal plane by an embossing depth. The embossed contour flank can transition into an adjacent sheet metal area at a sheet metal transition edge and be inclined with respect to the sheet metal plane. The geometric design of the embossed contour flank ensures a defined shape for the sealant. The inclined arrangement facilitates material flow and improves the sealant's adhesion. Furthermore, such an optimized embossed contour minimizes material failure or leakage at the sealing point.

[0013] The slot-shaped gap forming the KTL opening is bounded by sheet metal part cutting edges, which can be introduced into the sheet metal part using the cutting / embossing die. Of the two sheet metal part cutting edges, one can be formed at the free flank end of the embossing contour furthest from the transition edge, while the other sheet metal part cutting edge is located at the same height as the sheet metal part transition edge when viewed in the sheet metal part thickness direction. The sheet metal part transition edge and the sheet metal part cutting edge lying in the sheet metal part plane can define an embossing contour access area. The embossing contour access area can be covered by the embossing contour flank when viewed in the sheet metal part thickness direction. The precise delimitation of the slot-shaped gap described above ensures that no liquid sealant flows through, but remains completely contained.The optimized arrangement of the cutting edges prevents overfilling or uneven material distribution.

[0014] The width of the slot-shaped gap can be preferably dimensioned to ensure that the still-liquid sealant can bridge the gap during the application process. This prevents the liquid sealant from flowing through the slot-shaped gap. Such an optimized gap width guarantees a complete seal without material loss. Precise control of the gap bridging prevents the sealant from leaking out, thus improving the quality of the application. This, in turn, increases the reproducibility of the sealing process.

[0015] In one design variant, the embossed contour flank can be divided into a flank section near the transition edge, which is inclined relative to the sheet metal plane, and a flank section further away from the transition edge, which is parallel to the sheet metal plane. The combination of inclined and parallel sections improves the durability of the seal. The different flank sections also facilitate the targeted application and distribution of the sealant.

[0016] The body structure can be manufactured using the following process chain: a cathodic dip coating (KTL) process, in which the body structure is coated with KTL paint and the KTL paint is subsequently dried; an application process, in which a liquid sealant, particularly PVC sealant, is applied to seal seams between sheet metal parts of the body structure and / or to form underbody protection on the vehicle floor of the body structure; and a drying process, in which the applied liquid sealant is cured. In the application process, the liquid sealant can be used not only for seam sealing and / or underbody protection, but also for sealing the KTL opening. Integrating the sealing into the existing KTL and application process reduces production costs and manufacturing time.The multiple use of the available liquid sealing material for seam sealing, for underbody protection formation and for sealing the KTL opening also increases process and material efficiency.

[0017] An embodiment of the invention is described below with reference to the accompanying figures.

[0018] They show: Fig. Figures 1a to 3c show different views illustrating the sealing element of the KTL opening and its production.

[0019] In the Fig. 1a and Fig. Figure 1b shows a cathodic dip coating (KTL) opening 3 formed in a sheet metal part 5, which is sealed with a shapeless sealant 1. The sheet metal part 5 is part of a vehicle body structure (not shown). Unlike a conventional rubber plug or adhesive pad, the shapeless sealant 1 has no predefined shape and adapts flexibly to the geometry of the KTL opening 3. In contrast, a conventional rubber plug or adhesive pad is a prefabricated molded part with a defined geometry that must be precisely fitted into the KTL opening 3. For the sake of clarity, the following is shown in the Fig. 1a only the outline of the formless sealant 1 is indicated in a dotted line so that the holding geometry 7 of the KTL opening 3 is recognizable.

[0020] The starting component of the formless sealant 1 is a liquid PVC material 2, which is applied in an application process ( Fig. 3c) is applied in an application direction A by a robot-assisted applicator (not shown) to the e-coating opening 3. A key aspect of the invention is that the e-coating opening 3 is designed with a holding geometry 7, by means of which uncontrolled dripping or flow of the material generated during the application process ( Fig. 3c) is prevented from still being liquid sealing material 2.

[0021] As can be seen from the figures, the retaining geometry 7 is realized as a pocket-shaped embossed contour formed in one piece and with a uniform material in the sheet metal part 5, into which the liquid sealing material 2 is applied during the application process ( Fig. 3c) can be filled in application direction A. According to the Fig. 1a and Fig. Figure 1b shows that the pocket-shaped embossed contour 7 has an embossed contour flank 9. This flank projects from the sheet metal part plane E by an embossing depth t in a sheet metal part thickness direction d. The embossed contour flank 9 transitions into an adjacent sheet metal part area at a sheet metal part transition edge 11. Furthermore, the embossed contour flank 9 is subdivided into a flank section 13 near the transition edge, which is inclined with respect to the sheet metal part plane E, and into a flank section 15 further away from the transition edge, which is aligned parallel to the sheet metal part plane E.

[0022] The KTL opening 3 is formed in the figures as a slot-shaped gap directly within the pocket-shaped embossed contour 7. This gap is bounded by two sheet metal part cutting edges 17, 19, one of which, 17, is formed at the free flank end of the embossed contour flank 9, while the other, 19, is located at the same height as the sheet metal part transition edge 11 when viewed in the sheet metal part thickness direction d. The gap width s ( Fig. 1b) The KTL opening 3 is dimensioned such that in the application process ( Fig. 3c) The gap-bridging capability of the still liquid sealing material 2 is ensured, so that an uncontrolled flow of the liquid sealing material 2 through the KTL opening 3 is prevented. In addition, the embossed contour flank 9, viewed in the sheet metal thickness direction d, covers an access area of ​​the embossed contour 7, which is spanned in the sheet metal plane E between the sheet metal edge cutting edge 19 and the sheet metal transition edge 11.

[0023] The following describes a process chain for the production of the product in the Fig. 1 indicated sheet metal part 5 based on the block diagram of the Fig. As described in Figure 2: The body structure, including the sheet metal part 5, is first subjected to a cathodic dip coating (e-coating) process I, in which the sheet metal part 5 is dip-coated with an e-coating paint (not shown). The body structure, now dip-coated with the e-coating paint, is transferred to an e-coating oven to thermally cure the e-coating. In the next step of the process, an application process II takes place. In application process II, the liquid PVC sealant 2 is poured into the embossed contour 7 in application direction A. The plane-parallel flank section 15 of the embossed contour flank 9 forms an embossing base on which the liquid sealant 2 can be supported without dripping or flowing uncontrollably through the e-coating opening 3.

[0024] In application process II, not only is the KTL opening 3 sealed, but also, using appropriate applicators, a rough seam seal and underbody protection are applied to the underside of the vehicle floor of the body structure. For the rough seam seal, the liquid sealant 2 is applied to the joints between adjacent sheet metal parts, while for the underbody protection, the liquid sealant 2 is applied over a large area to the underside of the vehicle floor of the body structure. In a subsequent drying process III, the liquid sealant 2 is thermally cured to form the formless sealant 1.

[0025] In the Fig. Figures 3a to 3c indicate the forming process steps for producing the KTL opening 3 in the sheet metal part 5. Accordingly, the sheet metal part 5 is placed in a forming tool 21 ( Fig. 3a), which has a stroke-adjustable cutting / embossing die 23. The cutting / embossing die 23 is stroke-adjusted in an embossing direction P, forming the pocket-shaped embossing contour 7 ( Fig. 3b). The pre-direction P and the application direction A are aligned. REFERENCE MARK LIST: 1 formless sealant 2 liquid sealant 3 KTL openings 5 sheet metal parts 7 Holding geometry or pocket-shaped embossing contour 9 Embossed contour edge 11 Sheet metal part transition edge 13 sloping flank section 15 plane-parallel flank section 17 Sheet metal part cutting edge 19 Sheet metal part cutting edge 21 Forming tool 23 cutting / embossing stamps d Sheet metal part thickness direction E sheet metal part level t Embossing depth s gap width P Pre-judgment Application direction I, II, III Process steps

Claims

[1] Body structure for a vehicle, comprising a sheet metal part (5) in which at least one e-coating opening (3) is formed, which can be permeated by liquid e-coating paint in an e-coating process (I), wherein the e-coating opening (3) can be sealed with a sealing element (1) after the e-coating process (I), wherein the sealing element (1) is a sealant which can be applied to the e-coating opening (3) as a liquid sealing material (2) in an application process (II) and can be cured in a subsequent drying process (III), and wherein the e-coating opening (3) is associated with a retaining geometry (7) by means of which uncontrolled dripping or flow of the sealing material (2) which is still liquid in the application process (II) can be prevented, characterized by, that the retaining geometry (7) is a pocket-shaped embossed contour formed in the sheet metal part (5), that in the application process (II) the liquid sealing material (2) can be poured into the pocket-shaped embossed contour (7) in an application direction (A), and that the KLT opening (3) in the pocket-shaped embossed contour (7) is formed as a slot-shaped gap. [2] Body structure according to claim 1, characterized by , that the retaining geometry (7) is formed in a single material and / or in one piece on the sheet metal part (5), and that the retaining geometry (7) and the KTL opening (3) can be formed in a common sheet metal forming process in the sheet metal part (5), and / or that the pocket-shaped embossing contour (7) can be produced in the sheet metal forming process by means of a forming tool (21) with a stroke-adjustable cutting / embossing punch (23) which forms the embossing contour (7) into the sheet metal part (5) with an embossing stroke in an embossing direction (P). [3] Body structure according to claim 1 or 2, characterized by , that the embossing contour (7) has at least one embossing contour flank (9) which, viewed in a sheet metal part thickness direction (d), projects from the sheet metal part plane (E) by an embossing depth (t), and / or that the embossing contour flank (9) transitions into an adjacent sheet metal part area at a sheet metal part transition edge (11), and / or that the embossing contour flank (9) is inclined with respect to the sheet metal part plane (E). [4] Body structure according to any one of the preceding claims, characterized by, that the slot-shaped gap is limited by sheet metal part cutting edges (17, 19), and that of the two sheet metal part cutting edges (17, 19) one sheet metal part cutting edge (17) is formed at the free flank end of the embossing contour flank (9) furthest from the transition edge, while the other sheet metal part cutting edge (19) is located at the same height as the sheet metal part transition edge (11) when viewed in the sheet metal part thickness direction (d), and / or that the sheet metal part transition edge (11) and the sheet metal part cutting edge (19) lying in the sheet metal part plane (E) span an embossing contour access area, and that the embossing contour access area is covered by the embossing contour flank (9) when viewed in the sheet metal part thickness direction (d). [5] Body structure according to any one of the preceding claims, characterized by, that the gap width (s) of the slot-shaped gap is dimensioned such that in the application process (II) a gap bridging capability of the still liquid sealing material (2) is ensured, so that a flow of the liquid sealing material (2) through the slot-shaped gap is prevented. [6] Body structure according to one of claims 3, 4 or 5, characterized by , that the embossed contour flank (9) is divided into a flank section (13) near the transition edge, which is inclined with reference to the sheet metal part plane (E), and into a flank section (15) far from the transition edge, which is formed parallel to the sheet metal part plane (E). [7] Body structure according to any one of the preceding claims, characterized by that the body structure can be manufactured in the following process chain, with - a KTL process (I) in which the body structure is coated with the KTL paint and the KTL paint is then dried, - an application process (II) in which a seam seal between sheet metal parts of the body structure and / or an underbody protection formation on the vehicle floor of the body structure is achieved by applying liquid sealing material (2), - a drying process (III) in which the applied liquid sealing material (2) is cured, and that in the application process (II) the liquid sealing material (2) is not only used for seam sealing and / or for underbody protection formation, but is also used for sealing the KTL opening (3). [8] Sheet metal part (5) for a body structure of a vehicle according to one of the preceding claims, wherein at least one e-coating opening (3) is formed in the sheet metal part (5) which can be permeated by liquid e-coating in an e-coating process (I), and wherein the e-coating opening (3) can be sealed with a sealing element (1) after the e-coating process (I) has been carried out, wherein the sheet metal part (5) has a retaining geometry (7) by means of which uncontrolled dripping or flow of the liquid sealing material (2) applied to the e-coating opening (3) in the application process (II) can be prevented, characterized by , that the retaining geometry (7) is a pocket-shaped embossed contour formed in the sheet metal part (5), that in the application process (II) the liquid sealing material (2) can be poured into the pocket-shaped embossed contour (7) in an application direction (A), and that the KLT opening (3) in the pocket-shaped embossed contour (7) is formed as a slot-shaped gap. [9] Method for manufacturing a body structure according to any one of claims 1 to 7, in which a sheet metal part (5) is formed with at least one e-coating opening (3) through which liquid e-coating paint flows in an e-coating process (I), wherein the e-coating opening (3) is sealed with a sealing element (1) after the e-coating process (I) has been completed, wherein the sealing element (1) is a sealant which is applied to the e-coating opening (2) as a liquid sealing material (2) in an application process (II) and is cured in a subsequent drying process (III), and wherein the e-coating opening (3) is associated with a retaining geometry (7) by means of which uncontrolled dripping or flow of the sealing material (2) which is still liquid in the application process (II) can be prevented. characterized by, that the retaining geometry (7) is a pocket-shaped embossed contour formed in the sheet metal part (5), that in the application process (II) the liquid sealing material (2) can be poured into the pocket-shaped embossed contour (7) in an application direction (A), and that the KLT opening (3) in the pocket-shaped embossed contour (7) is formed as a slot-shaped gap.

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