Interior trim panel of a motor vehicle

Abstract

The invention relates to an interior trim panel (1) for a motor vehicle, said panel comprising a core (2) made of cardboard honeycomb, two upper (6) and lower (7) layers reinforcing said core, which are provided, on one of their faces (9), with a plurality of additional reinforcing mineral fibers (10), said fibers being oriented along a reference direction, extending continuously from one edge to another opposite edge of said panel, and being spaced from each other in a direction perpendicular (14) to said reference direction. Figure 2

Description

Title of the invention: Interior trim panel for motor vehicles

[0001] The invention relates to an interior trim panel for a motor vehicle, an assembly and a method for making such a panel.

[0002] It is known to produce an interior trim panel for a motor vehicle, said panel comprising: • a core made of cardboard honeycomb, said core having an upper face and a lower face connected to each other by an edge, • two upper and lower reinforcement layers of said core, said layers being based on entangled mineral reinforcing fibers embedded in polyurethane foam, said fibers generally having a length of less than 100 mm and being randomly oriented, said layers extending respectively over said upper and lower faces, said foam overmolding said core so as to associate said layers with said faces.

[0003] Such an arrangement makes it possible to produce a panel with good rigidity provided by a "beam effect" achieved by the reinforcement layers associated with each other through the web forming a means of spacing.

[0004] Such a panel is, for example, a false floor of a luggage compartment intended to be mounted in support on lateral supports provided in said compartment.

[0005] Since the reinforcing fibers are of short length and randomly oriented, the layers of said fibers intended to form the reinforcing layers have significant flexibility, which allows them to be easily shaped and to obtain a panel with a fine geometry at its periphery, in particular having radiating areas of small radius, for example less than 5 mm.

[0006] However, in order to provide sufficient flexural strength to such a panel, it is necessary to provide reinforcement layers with a high surface mass, for example with a surface mass of fibers of the order of 450 g / m2; the panel therefore has a significant mass.

[0007] To remedy this, consideration has been given to using reinforcement layers based on reinforcing fibers oriented along the same reference direction, said fibers extending continuously from one edge to another opposite edge of said panel.

[0008] However, such an embodiment does not allow for a fine geometric definition of the panel's periphery, due to the significant stiffness of the fiber layers intended to form the reinforcing layers, these layers then conforming diffi- cilement.

[0009] The invention aims to provide an arrangement that overcomes these drawbacks.

[0010] To this end, and according to a first aspect, the invention proposes an interior trim panel for a motor vehicle, said panel comprising: • a core made of cardboard honeycomb, said core having an upper face and a lower face connected to each other by an edge, • two upper and lower reinforcement layers of said core, said layers being based on entangled mineral reinforcing fibers embedded in polyurethane foam, said fibers generally having a length of less than 100 mm and being randomly oriented, said layers extending respectively over said upper and lower faces, said foam overmolding said core so as to bond said layers to said faces,

[0011] knowing that said reinforcing layers are provided, on one of their faces, with a plurality of additional reinforcing mineral fibers, said fibers: • being oriented along a reference direction, • extending continuously from one edge to the opposite edge of said panel, • being spaced apart from each other in a direction perpendicular to said reference direction.

[0012] Such an arrangement makes it possible, as will be seen later, to have a lightweight panel with good resistance to bending.

[0013] In addition, the use of additional reinforcing fibers in moderate quantity, and spaced apart from each other, makes it possible to obtain a fine definition of the peripheral geometry of the panel.

[0014] According to other aspects, the invention proposes an assembly and a method for making such a panel.

[0015] Other features and advantages of the invention will become apparent from the following description, made with reference to the accompanying figures, in which:

[0016] [Fig.1] is a partial schematic front view of a panel according to one embodiment,

[0017] [Fig.2] is a schematic partial cross-sectional view of the panel of [Fig.1] according to a method of implementation,

[0018] [Fig.3] is a schematic side view of the panel mounting of the preceding figures previous.

[0019] With reference to the figures, a panel 1 of interior trim for a motor vehicle is described, said panel comprising: • a core 2 based on a cardboard honeycomb structure, said core having an upper face 3 and a lower face 4 connected to each other by an edge 5, • two upper 6 and lower 7 reinforcement layers of said core, said layers being based on entangled mineral reinforcing fibers 8 embedded in polyurethane foam 20, said fibers generally having a length of less than 100 mm - in particular between 40 and 60 mm - and being randomly oriented, said layers extending respectively over said upper and lower faces, said foam overmolding said core so as to associate said layers with said faces,

[0020] knowing that said reinforcing layers are provided, on one of their faces 9, with a plurality of additional reinforcing mineral fibers 10, said fibers: • being oriented along a reference direction 11, • extending continuously from one edge 12 to another opposite edge 3 of said sign, • being spaced apart from each other in a direction perpendicular 14 to said reference direction.

[0021] According to one embodiment, the reinforcing fibers 8 and / or additional reinforcing fibers 10 are glass fibers.

[0022] According to one embodiment, the additional reinforcing fibers 10 are made up of a plurality of filaments entangled with each other.

[0023] According to one embodiment, the reinforcing fibers 8 are linked to each other by a bonding agent, for example of a thermoplastic nature.

[0024] According to one embodiment, the additional reinforcing fibers 10 are glued onto the reinforcing layers 8.

[0025] According to one embodiment, the additional reinforcing fibers 10 are arranged so as to have a surface mass between 50 and 150 g / m2 - and in particular between 90 and 110 g / m2.

[0026] According to one embodiment, the additional reinforcing fibers 10 are spaced regularly from each other according to a dimension 19 between 20 and 40 mm - and in particular between 25 and 35 mm.

[0027] According to one embodiment, the reinforcing layers 6,7 have a surface mass between 150 and 250 g / m2 - and in particular between 180 and 220 g / m2.

[0028] The additional reinforcing fibers 10 can be arranged as desired: • either on the outer face 9 of the reinforcing layers 6,7, as shown in [Fig.2], • either on the inner face of said reinforcing layers, according to a variant not shown.

[0029] For these two alternatives, an analogous resistance in bending was observed (see the test described later).

[0030] According to the embodiment shown in [Fig.2], panel 1 further comprises a top layer of covering 16, for example carpet, of the top reinforcing layer 6.

[0031] According to an embodiment not shown, the upper coating layer 16 extends over the slice 5 of the core 2.

[0032] According to various embodiments, the upper coating layer 16 is glued or overmolded by the foam 20 of the upper reinforcing layer 6.

[0033] According to the embodiment shown, the lower reinforcement layer 7 is coated with a lower coating layer 17, for example in non-woven material.

[0034] According to various embodiments, the lower coating layer 17 is glued or overmolded by the foam 20 of the lower reinforcing layer 7.

[0035] The bending resistance was examined: • of a reference panel, provided with two layers of glass-based reinforcement 6.7, each having a surface mass of fibers of 450 g / m2, said layers not being reinforced by additional reinforcing fibers 10, • and a panel 1 according to an embodiment of the invention, provided with two reinforcing layers 6,7 based on glass fibers, each having a surface mass of fibers of 200 g / m2, said layers being reinforced by additional reinforcing glass-based fibers 10 arranged so as to represent a surface mass of fibers of 100 g / m2.

[0036] It is further specified that the reference panels and those according to the invention have an analogous geometry and are provided with the same mass of polyurethane foam.

[0037] The bending test was carried out at 23°C by supporting the panels along two opposite edges 12,13 on two respective bases, the additional reinforcing fibers 10 extending from one of said edges to the other.

[0038] A disk with a diameter of 250 mm was then placed in support at the center of the panel.

[0039] Next, at a displacement speed of 100 mm / minute, a load of 100 daN.

[0040] We finally measured the deflection of the panel under 100 daN, then the residual deflection after removal of the disc.

[0041] The results are as follows: • Reference panel: deflection under load = 15 mm; residual deflection = 0.3 mm • panel according to the invention: deflection under load = 14.5 mm; residual deflection = 0.3 mm.

[0042] As can be seen, the panel exhibits in both cases an analogous flexural strength, and this with a weight reduction of 300 g / m2 (2x(450-(200+100)) for panel 1 according to the invention.

[0043] Furthermore, the panel 1 according to the invention has a fine geometry at its periphery, This is due to the good conformability of the reinforcing layers 6,7 provided with additional reinforcing fibers 10.

[0044] An assembly of such a panel 1 is now described with reference to [Fig. 3], said

[0045]

[0046] assembly including: • two opposing lateral supports, 18 • and said panel resting along two opposite edges 12,13, between which extend the additional reinforcing fibers 10, on each of said supports, so that said fibers extend from one of said supports to the other to reinforce the bending resistance of said panel. Finally, a manufacturing process for such a panel 1 is described, said process comprising the following steps: • provide a core 2 based on a cardboard honeycomb structure, said core having an upper face 3 and a lower face 4 connected by an edge 5, • arrange two layers, upper and lower, on each of said faces, said layers being based on entangled mineral reinforcing fibers 8, said fibers generally having a length of less than 100 mm and being randomly oriented, said layers being provided, on one of their faces, with a plurality of additional reinforcing mineral fibers 10, said fibers being oriented along a reference direction 11 and extending continuously from one edge 12 to another opposite edge 13 of said panel and spaced from each other in a direction perpendicular 14 to said reference direction, • pour a precursor mixture of polyurethane foam onto each of the said layers, • Place everything in the mold, • wait for the foam 20 to expand so as to form upper 6 and lower 7 reinforcing layers impregnated with foam, said foam overmolding said core so as to bond said layers to said faces, • remove the entire mold.

[0047] It may also be provided that at least one upper layer 16 and / or lower layer 17 of coating be associated with at least one reinforcing layer 6,7, in particular by bonding or by overmolding in the mold.

Claims

Claims

1. Interior trim panel (1) of a motor vehicle, said panel comprising: a core (2) based on cardboard honeycomb, said core having an upper face (3) and a lower face (4) connected together by a slice (5), two upper (6) and lower (7) layers for reinforcing said core, said layers being based on entangled mineral reinforcing fibers (8) embedded in polyurethane foam (20), said fibers generally having a length of less than 100 mm and being oriented randomly, said layers extending respectively on said upper and lower faces, said foam overmolding said core so as to associate said layers with said faces, said reinforcing layers being provided, on one of their faces (9), with a plurality of additional reinforcing mineral fibers (10), said fibers: being oriented according to a reference direction (11), extending continuously from one edge (12) to another opposite edge (13) of said panel, being spaced from each other in a direction perpendicular (14) to said reference direction. said panel being characterized in that the additional reinforcing fibers (10) are glued to the reinforcing layers (6,7).

2.

3. Panel according to claim 1, characterized in that the reinforcing fibers (8) and / or additional reinforcing fibers (10) are glass fibers. Panel according to any one of the preceding claims, ca characterized in that the additional reinforcing fibers (10) are arranged so as to have a surface mass of between 50 and 150 g / m2.

4. Panel according to any one of the preceding claims, ca

5.

6. characterized in that the additional reinforcing fibers (10) are regularly spaced from each other according to a dimension (19) of between 20 and 40 mm. Panel according to any one of the preceding claims, characterized in that the reinforcing layers (6, 7) have a surface mass of between 150 and 250 g / m2. Mounting of a panel (1) according to any one of the preceding claims, said mounting comprising: • two opposite lateral supports (18), • and said panel resting along two opposite edges (12, 13), between which extend the additional reinforcing fibers (10) glued to the reinforcing layers (6, 7), on each of said supports, such that said fibers extend from one of said supports to the other to reinforce the bending resistance of said panel.

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