Assembly of a floor covering panel of a motor vehicle
Patent Information
- Application Number
- EP2024709057
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-03-14
- Filing Date
- 2024-03-05
- Publication Date
- 2026-01-21
AI Technical Summary
Existing motor vehicle floor panels require a uniform surface density of reinforcing fibers for adequate bending resistance, leading to excessive fiber usage and increased cost and weight, as the middle part needs higher resistance than the peripheral parts.
The panel design features a cellular stiffening core with intertwined reinforcing fibers embedded in polyurethane foam, where the surface density of fibers is greater in the middle part than in the peripheral parts, optimizing fiber distribution to reduce mass and cost while maintaining bending resistance.
This design reduces the panel's mass by 20-30% while preserving bending resistance properties, resulting in cost savings and weight reduction.
Smart Images
Figure EP2024055747_19092024_PF_FP_ABST
Abstract
Description
[0001] DESCRIPTION
[0002] Title: Installation of a covering panel for the floor of a motor vehicle
[0003] The invention relates to an assembly of a covering panel for a motor vehicle floor, a panel of such an assembly and a method for producing such a panel.
[0004] It is known to produce an assembly of a covering panel for a floor of a motor vehicle, said assembly comprising said panel and at least two receiving zones for said panel originating from the body of said vehicle, said panel having at least two peripheral parts arranged along two of its opposite edges, said peripheral parts being respectively mounted to bear on each of said receiving zones, and a middle part extending between said peripheral parts without bearing, said panel comprising:
[0005] • a stiffening honeycomb core generally fitting into a rectangular parallelepiped defining a front face and a back face,
[0006] • two front and back layers of reinforcement in flexion of said core, said layers being based on entangled reinforcement fibers embedded in polyurethane foam, said reinforcement layers extending respectively on said front and back faces, said foam overmolding said core so as to associate said reinforcement layers with said front and back faces.
[0007] This results in a panel with reinforcing layers spaced apart by the core acting as a spacer to produce a “beam effect”.
[0008] According to known embodiments, the surface density of the reinforcing fibers is substantially uniform over the entire surface of the reinforcing layers. And it is necessary to provide a surface density of reinforcing fibers sufficient to allow the panel to have over its entire surface, and in particular in the middle part which has the lowest resistance to bending, a stiffness allowing it to receive a load without excessive bending.
[0009] However, such a high surface density of fibers is unnecessary near the peripheral parts which have a much higher bending strength than the middle part.
[0010] As a result, the surface density of fibers is dictated by the bending resistance that is desired in the middle part, this leading to excessive use of fibers, with the resulting disadvantages in terms of additional cost and excess weight of the panel.
[0011] The invention aims to overcome these drawbacks.
[0012] To this end, and according to a first aspect, the invention proposes an assembly of a covering panel for a motor vehicle floor, said assembly comprising said panel and at least two receiving zones for said panel originating from the body of said vehicle, said panel having at least two peripheral parts arranged along two of its opposite edges, said peripheral parts being respectively mounted to bear on each of said receiving zones, and a middle part extending between said peripheral parts without bearing, said panel comprising:
[0013] • a stiffening honeycomb core generally fitting into a rectangular parallelepiped defining a front face and a back face,
[0014] • two front and back layers of reinforcement in flexion of said core, said layers being based on entangled reinforcement fibers embedded in polyurethane foam, said reinforcement layers extending respectively on said front and back faces, said foam overmolding said core so as to associate said reinforcement layers with said front and back faces, the surface density in the middle part of said reinforcement fibers of each of said reinforcement layers being greater than said density in peripheral parts.
[0015] With the proposed arrangement, the surface density of the reinforcing fibers to be used is adapted to the different parts of the panel, the middle part being provided with a greater quantity of fibers than the peripheral parts which are lightened in fibers.
[0016] This results in a saving in cost and weight of the panel.
[0017] In particular, with the proposed arrangement, we produce panels whose mass can be reduced by around 20 to 30%, while preserving their flexural strength properties.
[0018] According to other aspects, the invention provides a panel of such an assembly and a method of producing such a panel.
[0019] Other features and advantages of the invention will appear in the following description, given with reference to the attached figures, in which:
[0020] [Fig.1] is a schematic front view of a panel of an assembly according to one embodiment, said panel having various types of peripheral parts, [Fig.2a] and
[0021] [Fig.2b] are schematic sectional views of an assembly in which the surface density of the reinforcing fibers varies in stages (figure 2a) and continuously (figure 2b).
[0022] With reference to the figures, an assembly 1 of a panel 2 for covering a floor of a motor vehicle - in particular a luggage compartment - is described, said assembly comprising said panel and at least two receiving zones 3 for said panel originating from the body of said vehicle, said panel having at least two peripheral parts 4 arranged along two of its opposite edges, said peripheral parts being respectively mounted to bear on each of said receiving zones, and a middle part 5 extending between said peripheral parts without bearing, said panel comprising:
[0023] • a cellular stiffening core 6 generally fitting into a rectangular parallelepiped defining a front face 7 and a back face 8,
[0024] • two layers of front 10 and back 11 for reinforcement in bending of said core, said layers being based on reinforcing fibers - for example mineral (glass, etc.) or vegetable (flax, hemp, etc.) - entangled and embedded in polyurethane foam, said reinforcing layers extending respectively on said front and back faces, said foam overmolding said core so as to associate said reinforcing layers with said front and back faces, the surface density in the middle part 5 of said reinforcing fibers of each of said reinforcing layers being greater than said density in peripheral parts 4.
[0025] According to one embodiment, the core 6 has a thickness 9 generally between 6 and 30 mm, the term “generally” meaning that this thickness can be locally reduced, in particular by compression, for example at the periphery of said core or in areas receiving attachment members.
[0026] According to the embodiment shown, the core 6 has a honeycomb structure, in particular based on cardboard or thermoplastic material.
[0027] In a variant not shown, the core 6 is in the form of a block based on rigid foam, i.e. not elastically compressible.
[0028] According to various embodiments, the surface density of the reinforcing fibers of each of the reinforcing layers 10, 11 increases, from the peripheral parts 4 to the middle part 5:
[0029] • either in stages, as shown in figure 2A,
[0030] • either continuously, as shown in figure 2B. According to the embodiment shown in figure 1, at least one peripheral part 4 (that at the bottom of the figure) extends along an edge of the panel 2, so that said panel rests along said edge on the corresponding receiving zone 3.
[0031] According to the same embodiment, two peripheral parts (those at the top in figure 1) are located respectively at the ends of an edge of the panel 2, so that said panel rests by two of its corners on the corresponding reception zones 3.
[0032] According to the embodiments shown in figures 2, the face 10 and back 11 reinforcement layers have the same distribution of the reinforcement fibers in surface mass, so as to ensure symmetrical bending reinforcement on the back and face of the panel 2.
[0033] According to one embodiment, the surface density of the reinforcing fibers in each of the reinforcing layers 10, 11 is between 100 and 600 g / m 2 .
[0034] According to one embodiment, the surface density of the polyurethane in each of the reinforcement layers 10, 11 is between 100 and 600 g / m 2 .
[0035] According to one embodiment, the surface density of the polyurethane is proportional - in particular in a 1 / 1 ratio - to that of the reinforcing fibers in each part 4,5 of the panel 2, such an arrangement making it possible to ensure homogeneous impregnation of the reinforcing fibers by the polyurethane over the entire surface of the reinforcing layers 10,11.
[0036] A panel 2 of an assembly 1 as described above is now described, said panel having at least two peripheral parts 4 arranged along two of its opposite edges and a middle part 5 extending between said peripheral parts, said panel comprising: • a cellular stiffening core 6 generally forming part of a rectangular parallelepiped defining a front face 7 and a back face 8,
[0037] • two layers of front 10 and back 11 for reinforcement in bending of said core, said layers being based on entangled reinforcing fibers embedded in polyurethane foam, said reinforcing layers extending respectively on said front and back faces, said foam overmolding said core so as to associate said reinforcing layers with said front and back faces, the surface density in the middle part 5 of said reinforcing fibers of each of said reinforcing layers being greater than said density in peripheral parts 4.
[0038] According to an embodiment not shown, the panel 2 further comprises a covering face layer, for example carpet, of the reinforcement face layer 10.
[0039] According to various embodiments, the covering face layer is glued or overmolded by the foam of the reinforcement face layer 10.
[0040] According to an embodiment not shown, the reinforcing backing layer 11 is coated with a coating backing layer, for example made of non-woven material.
[0041] According to various embodiments, the backing layer of the covering is glued or overmolded by the foam of the reinforcing backing layer 11.
[0042] Finally, a method for producing such a panel 2 is described, said method comprising the following successive steps:
[0043] • provide a cellular stiffening core 6 generally fitting into a rectangular parallelepiped defining a front face 7 and a back face 8,
[0044] • deposit on each of said faces reinforcing fibers and a precursor mixture of polyurethane foam, the surface density of said reinforcing fibers in the middle part 5 being greater than said density in the peripheral parts 4,
[0045] • place the whole thing in a mold,
[0046] • waiting for the foam to expand so as to form front 10 and back 11 reinforcement layers, said foam overmolding said core so as to associate said layers with said faces,
[0047] • remove the entire mold.
[0048] According to a first implementation of this method, not shown, the step of depositing reinforcing fibers and polyurethane foam precursor mixture on the front 7 and back 8 faces is carried out according to the following successive sub-steps:
[0049] • arrange on each of said faces a main sheet of reinforcing fibers, and at least one format - for example in the form of a medallion arranged in the central part of said faces, or even a strip extending between two opposite edges of said faces - of an additional sheet of reinforcing fibers in the middle part 5 of said main sheet, so as to increase in stages the surface mass of said fibers in said middle part,
[0050] • pour a precursor mixture of polyurethane foam onto each main layer with its additional layer.
[0051] According to a second implementation of this method, the step of depositing reinforcing fibers and polyurethane foam precursor mixture on the front 7 and back 8 faces is carried out by mixing reinforcing fibers with the polyurethane foam precursor mixture at the outlet of the casting head of said mixture, said casting head following a trajectory controlled by a robot, the quantity of fibers mixed with said mixture being introduced variably depending on the position of said casting head on its trajectory so as to arrange said fibers in increased quantity in the middle part 5 of said faces, the distribution of the surface mass of said fibers being carried out either in stages or discontinuously. It is also possible to provide for associating at least one coating layer on at least one reinforcing layer 10, 11, in particular by gluing or by overmolding in the mold.
Claims
CLAIMS 1. Mounting (1) of a panel (2) for covering a floor of a motor vehicle, said mounting comprising said panel and at least two receiving zones (3) for said panel originating from the body of said vehicle, said panel having at least two peripheral parts (4) arranged along two of its opposite edges, said peripheral parts being respectively mounted to bear on each of said receiving zones, and a middle part (5) extending between said peripheral parts without bearing, said panel comprising: • a stiffening honeycomb core (6) generally fitting into a rectangular parallelepiped defining a front face (7) and a back face (8), • two front (10) and back (11) layers of flexural reinforcement of said core, said layers being based on entangled reinforcing fibers embedded in polyurethane foam, said reinforcing layers extending respectively on said front and back faces, said foam overmolding said core so as to associate said reinforcing layers with said front and back faces, said panel being characterized in that the surface density in the middle part (5) of said reinforcing fibers of each of said reinforcing layers is greater than said density in peripheral parts (4).
2. Assembly according to claim 1, characterized in that the core (6) has a honeycomb structure.
3. Assembly according to one of the preceding claims, characterized in that the surface density of the reinforcing fibers of each of the reinforcing layers (10, 11) increases, from the peripheral parts (4) to the middle part (5): • either in stages, • either continuously.
4. Assembly according to any one of the preceding claims, characterized in that at least one peripheral part (4) extends along an edge of the panel (2), so that said panel rests along said edge on the corresponding receiving zone (3).
5. Assembly according to any one of the preceding claims, characterized in that two peripheral parts (4) are located respectively at the ends of an edge of the panel (2), so that said panel rests by two of its corners on the corresponding receiving zones (3).
6. Assembly according to any one of the preceding claims, characterized in that the face (10) and back (11) reinforcing layers have the same distribution of reinforcing fibers in surface mass.
7. Panel (2) of an assembly according to any one of the preceding claims, said panel having at least two peripheral parts (4) arranged along two of its opposite edges and a middle part (5) extending between said peripheral parts, said panel comprising: • a stiffening honeycomb core (6) generally fitting into a rectangular parallelepiped defining a front face (7) and a back face (8), • two front (10) and back (11) layers of flexural reinforcement of said core, said layers being based on entangled reinforcing fibers embedded in polyurethane foam, said reinforcing layers extending respectively on said front and back faces, said foam overmolding said core so as to associate said reinforcing layers with said front and back faces, said panel being characterized in that the surface density in the middle part (5) of said reinforcing fibers of each of said reinforcing layers is greater than said density in peripheral parts (4).
8. Method for producing a panel according to claim 7, said method comprising the following successive steps: • provide a stiffening honeycomb core (6) generally fitting into a rectangular parallelepiped defining a front face (7) and a back face (8), • deposit on each of said faces reinforcing fibers and a precursor mixture of polyurethane foam, the surface density of said reinforcing fibers in the middle part (5) being greater than said density in the peripheral parts (4), • place the whole thing in a mold, • waiting for the foam to expand so as to form front (10) and back (11) reinforcement layers, said foam overmolding said core so as to associate said layers with said faces, • remove the entire mold.
9. Method according to claim 8, characterized in that the step of depositing reinforcing fibers and polyurethane foam precursor mixture on the front (7) and back (8) faces is carried out according to the following successive sub-steps: • arrange on each of said faces a main sheet of reinforcing fibers, and at least one format of an additional sheet of reinforcing fibers in the middle part (5) of said main sheet, so as to increase in stages the surface mass of said fibers in said middle part, • pour a precursor mixture of polyurethane foam onto each main layer with its additional layer.
10. Method according to claim 8, characterized in that the step of depositing reinforcing fibers and polyurethane foam precursor mixture on the front (7) and back (8) faces is carried out by mixing reinforcing fibers with the polyurethane foam precursor mixture at the outlet of the casting head of said mixture, said casting head following a trajectory controlled by a robot, the quantity of fibers mixed with said mixture being introduced variably depending on the position of said casting head on its trajectory so as to arranging said fibers in increased quantity in the middle part (5) of said faces, the distribution of the surface mass of said fibers being carried out either in stages or discontinuously.