Roof shell with acoustic insulation layer

Abstract

Roof shell (10) of a motor vehicle, comprising a planar, rigid composite component (16) with an outer side facing away from a vehicle interior and an inner side facing the vehicle interior, wherein the composite component (16) comprises a core of a paper honeycomb or a foam which is provided on the top and bottom with a polyurethane / glass fiber mixture, characterized in that an acoustic damping layer (24) is arranged on the inner side of the composite component (16) and that the planar, rigid composite component (16) has on its inner side at least one trough-like recess (20) which is filled with an open-pore foam material which forms the acoustic damping layer (24) and whose surface is flush with a surface (22) of the composite component (16) which encloses the recess (20), wherein the foam material is molded into the trough-like recess (20) according to a foaming process in a foaming tool.

Description

The invention relates to a roof shell of a motor vehicle having the features of the preamble of claim 1.Such a roof shell is known from the publication DE 10 2012 104 542 A1 and comprises a carrier and an outer skin. The carrier comprises a core and a polyurethane / glass fibre layer on each side of the core. The core is formed of a paper honeycomb.The publication EP 2 857 263 B1 discloses a vehicle roof with a roof shell into which a roof element is inserted, which is intended to increase the rigidity of the roof. The roof element comprises a corrugated cardboard into which a damping, planar structural element is inserted.From the publication US 2008 / 0128202 A1 and from the publication DE 10 2008 062 701 A1, a composite component is known in each case, which accommodates sound-absorbing elements.A further roof shell is known from practice and can be a fixed roof of a motor vehicle or else a roof segment of a folding roof of a convertible vehicle formed from a plurality of rigid roof segments. The roof shell can be designed as a so-called composite module which comprises a planar, rigid composite component which is provided on its inner side with an additional acoustic insulation layer. The composite component can be produced in a sandwich construction and comprise a core layer which is formed, for example, from a paper honeycomb or a foam material and is provided on both sides with a glass fibre / polyurethane mixture. In addition, the composite component can comprise an outer skin of the relevant vehicle roof, which is therefore adapted to the design of the relevant vehicle. The acoustic insulation layer serves for acoustic insulation of the vehicle interior from the vehicle environment. In acoustic insulation layers used hitherto, there is the problem that transitions between the acoustic insulation layer and the composite component and also unevennesses of the inner side of the composite component can be produced via the acoustic insulation layer on the inner side of the roof shell, in particular on a laminated-on inner lining fabric.The object of the invention is to create a roof shell of the type mentioned in the introduction with an optimized acoustic insulation layer.This object is achieved according to the invention by the roof shell having the features of claim 1.A roof shell of a motor vehicle is therefore proposed, which comprises a planar, rigid composite component with an outer side and an inner side which faces a vehicle interior. In addition, the roof shell comprises an acoustic insulation layer which is arranged on the inner side of the composite component. The composite component has on its inner side at least one trough-like depression which is filled with an open-pored foam material which forms the acoustic insulation layer and the surface of which is aligned with the surface of the composite component which encloses the depression.In the roof shell formed according to the invention, the edges of the composite component therefore remain free of the acoustic insulation layer. The acoustic insulation layer therefore does not extend as far as the edges of the rigid composite component. This ensures that the inner side of the roof shell can be laminated and the edges of the lamination can have a fold which overlaps the edges of the composite component. It should also be ensured, of course, that the open-pored foam material with which the trough-like depression is filled does not undergo shrinkage during curing, so that no height offset or gap results between the surface of the composite component enclosing the depression and the foam material filling the trough-like depression. This results in good laminating properties for the inner side of the roof shell.In a preferred embodiment of the roof shell according to the invention, the open-pored foam material is a fine-pored soft foam. In particular, the fine-pore soft foam can be a polyurethane foam having a density of between 50 kg / m 3 and 80 kg / m 3.The foam material is introduced into the trough-shaped depression in a foaming tool after a foaming process. Such a foaming process can take place with short process times, i.e. with a high cycle. In addition, a high process stability can be achieved by the shape-bound process in the foaming tool, which in turn promotes the expenses for quality assurance.In the foaming process in the foaming tool, an external release agent having a pore-opening effect is preferably used. This promotes the acoustic insulation properties of the foam material.The bottom of the trough-like depression can have unevennesses or even jumps or can also be wavy. This can be caused by functional elements which are accommodated by the composite component. The foam material which forms the acoustic insulation layer accommodates or encloses these irregularities, but is preferably smooth or planar on its upper side, that is to say it is formed without cracks. As a result, the system is independent of influences which can be caused by changes in geometry of the composite component.A roof shell of a motor vehicle, which is not covered by the claims, comprises a planar, rigid composite component with an outer side and an inner side which faces a vehicle interior. An acoustic insulation layer, which is arranged on the inner side of the composite component, is formed from at least one rigid foam or semi-rigid foam plate, which is bonded to the inner side of the composite component and is pressed in such a way that its volume is reduced compared to a pre-assembly state.The rigid foam or semi-rigid foam panel, which is bonded to the composite component over a large area or partially, absorbs unevennesses or surface cracks of the composite component as a result of the pressing in a suitable pressing tool, whereas the outer side, that is to say the side of the foam material facing away from the composite component, is formed smooth or planar, with the result that lamination with an inner lining material is possible, which then forms a class A surface. An additional inner lining element can thus be dispensed with.The production of the roof shell with the rigid foam or semi-rigid foam panel takes place in such a way that the composite component is first produced in a corresponding molding tool. The rigid foam or semi-rigid foam panel is then pressed onto the composite component. For the connection to the composite component, an adhesive system, for example a spray adhesive or the like, can be used. The joining and pressing are preferably carried out in a press.If necessary, a pressing tool with component receptacles can be used. In this case, in particular one tool half of the tool receives the composite component in a form-fitting manner, with the result that a uniform pressure distribution is ensured during the pressing operation and damage to the composite component is avoided. A second tool half can be geometrically designed such that jumps in height, depressions and transitions are pressed into the rigid foam or semi-rigid foam plate during pressing. These deformations remain in the volume-reduced rigid foam plate or semi-rigid foam plate after the pressing process. Accordingly, height jumps, depressions and transitions of the composite component caused, for example, by insert parts are pressed into the rigid foam or semi-rigid foam plate. Gaps, corrugations or other defects in the composite component thus do not impair the appearance of the roof shell on the inner side.As can be seen from the above explanations, the acoustic insulation layer provided by the rigid foam or semi-rigid foam panel is preferably bonded to the composite component by a shape-bound pressing process. This can be effected with a high process stability and thus with low expenses for quality assurance. The resulting component made of the composite component and the pressed rigid foam or semi-rigid foam panel offers good lamination capability with simultaneously good acoustic insulation effect.Furthermore, the roof shell with the pressed rigid foam or semi-rigid foam panel is distinguished by low production costs, since only small investments have to be applied for the pressing tool in comparison with foaming tools. In addition, a rigid foam or semi-rigid foam panel has good dimensional stability.The rigid foam or semi-rigid foam panel expediently consists of an open-pored rigid foam, which promotes the acoustic insulation properties.Preferably, the rigid foam or semi-rigid foam sheet in the pressed state has a density of between 50 kg / m 3 and 150 kg / m 3.A polyurethane-ester foam, a polyethylene foam or another foam material suitable for the respective roof shell can be used as material for the rigid foam or semi-rigid foam panel.In a specific embodiment, the roof shell according to the invention forms a roof shell of a folding roof of a convertible vehicle formed from rigid roof shells. The roof shell is then therefore a component of a so-called RHT (Traceable Hard Top). However, it can also be a flat bow of a so-called flat bow roof with a foldable roof covering.Further advantages and advantageous embodiments of the subject matter of the invention can be derived from the description, the drawing and the patent claims.An exemplary embodiment of a roof shell according to the invention is shown in a schematically simplified manner in the drawing and is explained in more detail in the following description. It shows: FIG. 1 shows a perspective top view of a roof shell of a convertible top; FIG. 2 shows a section through the roof shell according to FIG. 1 along the line II-II in FIG. 1 ; FIG. 3 ashows an embodiment of a roof shell not covered by the claims before having a composite component and an acoustic insulation layer; and FIG. 3 bshows the roof shell according to FIG. 3 ain the finished state.FIGS. 1 and 2 show a roof shell 10 which is a rigid roof segment of a multi-shell hinged roof of a convertible vehicle. The roof shell 10 is connected on both sides to two links 12 and 14 in each case for connection to a convertible top linkage of the folding roof or RHT with respect to a vertical longitudinal middle plane of the roof.The roof shell 10 represents a composite element which comprises as base a composite component 16 which comprises a core made of a paper honeycomb or a foam. The core is provided at the top and bottom with a polyurethane / glass fibre mixture. On its outer side, i.e. on its side facing away from the vehicle interior, the composite component 16 is provided with a plastic film 18 which forms the outer skin of the roof shell 10.On its inner side, which faces the vehicle interior, the composite component 16 has a trough-like depression 20, which is surrounded in a frame-like manner by a surface 22 of the composite component 16. The trough-like depression is filled with an open-pored foam material which forms an acoustic insulation layer 24. The open-pored foam material of the acoustic insulation layer 24 is a fine-pored flexible polyurethane foam with a density of about 50 kg / m 3 to 80 kg / m 3 and is introduced after a foaming process in a foaming tool in a shape-bonded manner into the trough-shaped depression 20. As can be seen from FIG. 2, the acoustic insulation layer 24 has an upper side, that is to say a side facing away from the plastic film 18, which is aligned with the frame-like surface 22 of the composite component 16. This means that the acoustic insulation layer 24 merges without cracks and without gaps into the surface 22.Furthermore, the roof shell 10 has on its inner side a fabric covering 26 which covers both the acoustic insulation layer 24 and the surface 22 of the composite component 16 and overlaps the edges of the composite component 16 with a fold. Due to the flush configuration of the surface of the acoustic insulation layer 24 and the surface 22, the transition between these two regions cannot be seen in the fabric lining 26 which forms the inner visible surface of the roof shell 10. For the best possible acoustic design, the surface 22 is kept as small as possible, so that the surface of the acoustic insulation layer 24 is designed as large as possible.FIGS. 3 aand 3 b show an alternative embodiment of a roof shell 10' of a folding roof of a convertible vehicle, which is designed as a so-called RHT. The roof shell 10' likewise has as base a composite component 16', which comprises a core made of a paper honeycomb, which is covered on both sides with a polyurethane / glass fiber mixture. On its outer side, the composite component 16' has a plastic film 18 which forms the outer skin of the roof shell 10' facing the vehicle environment.On its inner side, the composite component 16 is provided with an acoustic insulation layer 28, which is formed from a rigid polyurethane ester foam or a semi-rigid polyethylene foam and is bonded to the composite component 16 and, in addition, as can be seen from FIG. 3 b, is pressed in such a way that its volume is reduced compared to the pre-assembly state illustrated in FIG. 3 a. The rigid foam or semi-rigid foam of the acoustic insulation layer 28 is open-pored and has a density of between 50 kg / m 3 and 150 kg / m 3. in the pressed state shown in FIG. 3 b.During production, the composite component 16' is inserted into a mold half of a pressing tool. The acoustic insulation layer 28 is placed in another mold half in the non-pressed state. In addition, the exposed side facing acoustic insulation layer 28 is provided with an adhesive, for example with a spray adhesive. Subsequently, the pressing tool is closed according to the arrows P in FIG. 3 a, so that the two tool halves are moved against one another and the acoustic insulation layer 28 is pressed onto the inner side of the composite component 16' and bonded to the latter via the adhesive layer. In this case, as can be seen from a comparison of FIGS. 3 aand 3 b, the volume of the acoustic insulation layer 28 is reduced, that is to say its thickness is reduced. In addition, unevennesses or jumps in thickness 30 of the composite component 16' are absorbed by the acoustic insulation layer 28, since these are pressed into the rigid foam and semi-rigid foam material. The side of the acoustic insulation layer 28 facing the vehicle interior remains smooth.In a final step, the component provided with the acoustic insulation layer 28 is also provided with a fabric covering 26 which overlaps the edges of the acoustic insulation layer 28 with a fold.List of reference characters10, 10' Roof shell 12 Guide rod 14 Guide rod 16, 16' Composite component 18 Plastic film 20 Depression 22 Surface 24 Acoustic insulation layer 26 Fabric lining 28 Acoustic insulation layer

Claims

Roof shell (10) of a motor vehicle, comprising a planar, rigid composite component (16) having an outer side which faces away from a vehicle interior and an inner side which faces the vehicle interior, wherein the composite component (16) comprises a core made of a paper honeycomb or a foam which is provided at the top and at the bottom with a polyurethane / glass fibre mixture, characterized in that an acoustic insulation layer (24) is arranged on the inner side of the composite component (16), and in that the planar, rigid composite component (16) has at least one trough-like depression (20) on its inner side, which depression is filled with an open-pored foam material which forms the acoustic insulation layer (24) and the surface of which depression is flush with a surface (22) of the composite component (16) which surrounds the depression (20), wherein the foam material is introduced in a foaming tool in a shape-bonded manner into the trough-shaped depression (20) according to a foaming process.Roof shell (10) according to Claim 1, characterized in that the open-pored foam material is a fine-pored soft foam.Roof shell (10) according to claim 1 or 2, characterized in that the foam material has a density between 50 kg / m 3 and 80 kg / m 3.Roof shell (10) according to one of Claims 1 to 3, characterized in that the acoustic insulation layer (24) accommodates surface jumps of the composite component and is preferably of smooth and open-pored form on its upper side.Roof shell (10) according to one of Claims 1 to 4, characterized bya fabric covering (26) which forms an inner visible surface of the roof shell (10).Roof shell (10) according to one of Claims 1 to 5, characterized in that the acoustic insulation layer (24) is formed from a polyurethane foam, a polyurethane ester foam or a polyethylene foam.Roof shell (10) according to one of Claims 1 to 6, characterized in that it is a roof shell (10) of a folding roof of a convertible vehicle formed from rigid roof shells (10), or is a surface bow of a surface bow roof of a convertible vehicle.

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