Automotive Vehicle Structure

Abstract

The present invention relates to a structure (1) for an electric or hybrid vehicle comprising a floor (3), a battery container (4) fixed below the floor (3), and a compressed foam plate (2) placed between the battery container (4) and the floor (3). The present invention also relates to a vehicle comprising said structure (1), and to an assembly method.

Description

[Technical field]

[0001] The present invention relates to a structure for a motor vehicle. The invention further relates to a vehicle equipped with such a structure and to a method for assembling such a structure. [Background technology]

[0002] Vehicles, especially motor vehicles, generate vibrations which must be reduced in order to improve the ride comfort of these vehicles, and which in particular cause noise.

[0003] US Patent Application No. 2008 / 136110 A1 is known which describes a system for sound insulation between the floor of a vehicle and an energy reservoir, which may be either a fuel tank or a battery tray. The space between the fuel tank and the floor is sealed with an acoustic seal to prevent noise from being transmitted into the enclosed space.

[0004] However, this solution, although it provides insulation against sound, does not provide insulation against vibrations. Summary of the Invention

[0005] The object of the present invention is to provide a vehicle structure which obviates the above mentioned drawbacks, in particular, a vehicle structure which is simple and easy to install and which allows insulating the vehicle floor against noise and vibrations.

[0006] The present invention relates to a structure for an electric or hybrid vehicle that includes a floor, a battery tray secured below the floor, and a compressed foam plate disposed between the battery tray and the floor.

[0007] In one embodiment, the surface layer of the foam board comprises micropores configured to allow air contained within the foam to escape when the board is compressed and / or configured to prevent the ingress of moisture into the foam.

[0008] In one embodiment, the foam plate further comprises holes opening on one side of the foam plate or penetrating the foam plate from one side to the other, the holes being configured to allow air contained in the foam to escape when the plate is compressed.

[0009] In one embodiment, the foam panel is located near the rear of the vehicle and further comprises a portion having a surface with holes configured to allow air contained in the foam to escape when the panel is compressed.

[0010] In one embodiment, the foam board is compressed between the floor and the battery tray by a compression ratio of 20% to 40%, in particular 30% to 40%.

[0011] In one embodiment the foam plate has a thickness when compressed of ≧10mm≦20mm, preferably ≧13mm≦14mm, especially equal to or substantially equal to 13mm, and the plate has a compressibility of 30%.

[0012] In one embodiment, the foam board is made of polyurethane foam. Includes .

[0013] In one embodiment, the foam has a cell size of less than 2 mm.

[0014] The invention also relates to a vehicle, in particular a hybrid or electric motor vehicle, equipped with a structure according to the invention.

[0015] Finally, the present invention relates to a method of assembling a vehicle structure including the steps of drilling a foam board, placing the foam board between a floor of the vehicle and a battery tray of the vehicle, compressing the foam board to a compression ratio of 20% to 40%, and fastening the battery tray to the floor such that the foam board remains compressed to a compression ratio of 20% to 40%.

[0016] The accompanying drawings show, by way of example, an embodiment of a vehicle structure according to the invention. [Brief description of the drawings]

[0017] [Figure 1] FIG. [Diagram 2] FIG. [Figure 3A] FIG. 2 is a top view of a foam board according to a first embodiment for optimizing air evacuation. [Figure 3B] FIG. 13 is a top view of a foam board according to a second embodiment for optimizing air evacuation. [Figure 3C] FIG. 13 is a top view of a foam board according to a third embodiment for optimizing air evacuation. [Figure 4] FIG. 1 is an exploded view of a vehicle structure according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] An example of a vehicle structure according to an embodiment of the present invention will now be described with reference to FIG.

[0019] The structure 1 comprises a vehicle floor 3 and a battery tray 4. The battery tray 4 is fixed to the floor 3. In particular, the battery tray is fixed below the floor 3. The expression "below" is to be understood in this case to mean that the battery tray 4 is below the floor 3 when the vehicle comprising the structure is in operation. The battery tray 4 is therefore preferably adapted to be arranged outside the passenger compartment of the vehicle.

[0020] The vehicle structure 1 further comprises a foam plate 2. The foam plate 2 is arranged between a battery tray 4 and a floor 3 of the vehicle structure 1.

[0021] The floor 3 advantageously constitutes the horizontal floor surface of the passenger compartment of the vehicle.

[0022] The floor 3 is not limited to being a first layer on the inside of the passenger compartment of the vehicle, but may include multiple layers or assemblies, at least one of which is disposed on an interior surface of the vehicle.

[0023] The battery tray 4 may have at least a portion that is a cuboid or substantially parallelepiped in shape.

[0024] 2, the battery tray 4 includes a battery 43. The battery 43 is preferably electrically connected to an electric motor of the vehicle. In one embodiment, the battery tray 4 includes a cooling system 42. The cooling system 42 is preferably disposed below the battery 43.

[0025] The battery tray 4 further comprises a compartment or enclosure adapted to contain a battery and a cooling system. A top surface 41 of the compartment is in contact with or oriented towards the foam plate 2.

[0026] The width and length of the foam plate 2 are significantly greater than the thickness of the foam plate 2, i.e., the foam plate 2 preferably has two major faces separated by the smaller dimension, the so-called thickness.

[0027] The expression "significantly greater" is understood to mean that the width and length are at least 10 times greater than the thickness, preferably at least 50 times greater.

[0028] The foam slab 2 is a solid foam slab 2. The foam slab 2 may be made of an open or closed cell material. The open cell material includes a micro-shaped solid matrix impregnated with a fluid. The open cell material preferably includes a continuous solid network with air bubbles trapped therein.

[0029] Preferably, the foam board 2 consists of a polymer foam.

[0030] Polymer foam advantageously makes it possible to realize a foam plate 2 .

[0031] Preferably, the foam plate 2 consists of a polymer matrix, most preferably a polyurethane matrix.

[0032] The foam board 2 may include a fire retardant formulation so that the foam board 2 may also serve as a fire barrier between the battery tray 4 and the floor 3 of the vehicle structure 1.

[0033] Open-cell or closed-cell materials can be characterized by the density and structure of the matrix, particularly the porosity and cell shape.

[0034] The loss factor (or internal damping coefficient) of an open cell material may be 0.1 to 0.3 at a frequency of 10 Hz and a temperature of 23° C. The loss factor is a measure of the ratio of the energy dissipated by damping to the elastic energy stored and then re-stored during a deformation cycle.

[0035] The loss factor is equal to the tangent of the ratio of the loss modulus to the storage modulus (E').

[0036] The storage modulus (E') of the open cell material under compression can be 1000 to 50000 Pa at a frequency of 10 Hz and a temperature of 23°C.

[0037] The density of the open cell material can be from 20 to 100 g / L.

[0038] Preferably, the foam plate 2 is made of a microcellular material, ie the size of the cells in the network is between 1 μm and 1 mm.

[0039] In one embodiment, the foam is a closed cell foam, with the cell dimensions being less than 2 mm.

[0040] The foam plate 2, which is placed between the floor 3 and the battery tray 4, is compressed or pre-pressurized. Indeed, compressing the foam plate 2 advantageously allows a better absorption of vibrations and sound of the floor 3. Compression increases the stiffness of the plate.

[0041] In one embodiment, the foam board 2 is compressed by a force perpendicular to both major faces, ie, compressed such that the thickness of the foam board 2 decreases.

[0042] The battery tray 4 may be mechanically fixed to the floor 3 in a manner that leaves a space (between the battery tray and the floor 3) that is smaller than the thickness of the foam plate 2 in its free state, i.e. without any load on the plate. Thus, the foam plate 2 is deformed during installation by the compression exerted by the floor 3 and the upper surface 41 of the battery tray 4.

[0043] The vehicle structure may comprise fastening means by which the battery tray 4 can be fixed to the floor 3. The fastening means preferably allows for fastening without penetrating the foam plate 2.

[0044] In one embodiment, the compressibility of the foam board 2 is between 20% and 60%. Preferably, the compressibility of the foam 2 is about 30%. The expression "compressibility" is to be understood as the ratio of the difference between the thickness of the foam board 2 in the free state and the thickness of the foam board 2 when compressed, divided by the thickness of the foam board 2 in the free state.

[0045] The foam board 2 can be 10mm to 20mm thick when compressed between the floor 3 and the battery tray 4. Preferably, the foam board 2 is about 20mm thick in its free state. When the structure is installed, the foam board 2 is compressed by about 30%. That is, the thickness of the foam board 2 after being compressed and fitted between the floor 3 and the battery tray 4 is about 13mm.

[0046] The foam plate 2 also comprises means for venting air contained in the solid matrix, which makes it possible to vent air from the foam plate 2 when it is compressed, making it possible to reduce the risk of the plate 2 bursting due to the build-up of air pressure during compression.

[0047] In the first embodiment shown in Fig. 3A, at least one surface layer of the foam board 2 is provided with micropores. The surface layer with micropores is preferably the upper surface of the foam board 2. In that case, the air discharge is not hindered by the surface of the floor 3 or the battery tray 4.

[0048] The micropores extend through part of the volume of the foam plate 2, so that air trapped in the network of the solid matrix can more easily exit this matrix through the pores.

[0049] The pores may have a thickness or diameter of 0.05 mm to 3 mm. The pores may extend within the volume of the foam slab 2 over 20% to 99% of the length or width of the foam slab 2.

[0050] In one embodiment, at least one microperforation traverses the foam board 2 across its length or width.

[0051] The foam plate 2 may have a pore density of 2 to 10 pores per square millimeter, preferably 2 to 6 pores per square millimeter.

[0052] These properties of the micropores advantageously allow for better evacuation of air contained in the foam upon compression of the board and help prevent the ingress of moisture into the foam.

[0053] The microperforations can be arranged on both sides of the plate 2, but preferably only one of the two sides should have microperforations, which side should be arranged on the upper side of the plate 2, i.e. facing towards the passenger compartment of the vehicle (in contact with the floor of the automotive vehicle structure).

[0054] In a second embodiment shown in Figure 3B, the foam slab 2 includes at least one aperture 7 opening onto at least one major surface, specifically the aperture 7 penetrating the thickness of the slab. The aperture 7 serves to minimize the distance that air must travel to exit the foam slab 2.

[0055] If the foam plate 2 includes a single aperture 7 , that aperture 7 is preferably located in a central region of the foam plate 2 .

[0056] In one embodiment, the area of ​​the orifice of aperture 7 is less than 5%, or less than 1%, of the area of ​​foam panel 2 adapted to abut against battery tray 4 or the area of ​​foam panel 2 adapted to abut against floor 3.

[0057] In one embodiment in which the foam plate 2 has a number of apertures 7, the total area of ​​the orifices of the apertures 7 is less than 20%, or less than 10%, of the area of ​​the foam plate 2 adapted to abut against the battery tray 4 or the area of ​​the foam plate 2 adapted to abut against the floor 3.

[0058] The above second embodiment can also be combined with the first embodiment.

[0059] In a third embodiment shown in FIG. 3C, which is compatible with the first and / or second embodiments, a foam panel 2 is positioned near the rear of the vehicle and includes a portion having holes 8 on its surface for venting air.

[0060] In fact, by arranging the larger diameter holes 8 in the rear area, it is possible to exhaust a larger amount of air. This solution is particularly effective when the fine holes are not capable of exhausting a large amount of air in a relatively short time. The rear area, facing away from the direction of travel of the vehicle, has less stringent requirements in terms of durability.

[0061] In this way the risk of air overpressure in the centre of the matrix is ​​reduced.

[0062] So the assembly with the battery tray 4 and foam plate 2 under the floor 3 creates a mass-spring-mass effect. The vibrations of the battery tray 4 walls and sound waves are damped in the spring (foam plate 2). Finally, sound and vibration are damped.

[0063] In one embodiment, the battery tray 4 includes at least one fastening area 6. The at least one fastening area 6 may extend laterally relative to the upper surface 41.

[0064] The top surface 41 may be positioned to leave space (between the battery tray 4 and the floor 3) for inserting the foam board 2 as described above.

[0065] At least one fastening area 6 may comprise fastening means, such as drilled or screw holes, for fastening the battery tray 4 to the floor 3 .

[0066] The invention also relates to a vehicle comprising the above-mentioned structure 1. The vehicle preferably relates to a motor vehicle, most preferably an automobile, comprising an electric motor for moving the vehicle.

[0067] The invention also relates to a method for assembling the vehicle structure 1. An embodiment of the assembly method is described below. The vehicle structure 1 is preferably the vehicle structure 1 described above.

[0068] The method includes the following steps: - placing a foam plate 2 between the floor 3 of the vehicle and a battery tray 4; - compressing the foam board 2 to a compression ratio of 20% to 40%; - fixing the battery tray 4 to the floor 3 so as to separate them by a distance less than the thickness of the foam plate 2 in its free state; It is.

[0069] Preferably, the distance is 60% to 80% of the thickness of the foam board 2 in a free state.

[0070] In one embodiment, the compressing and fixing steps are performed simultaneously.

[0071] In this application, the expression "about" when followed by a numerical value is to be understood as a range of 10% on either side of that numerical value.

Claims

1. A vehicle structure (1) for an electric or hybrid vehicle, comprising a floor (3), a battery tray (4) fixed under the floor (3), and a compressed foam plate (2) arranged between the battery tray (4) and the floor (3), A structure (1), wherein the surface layer of the foam board (2) comprises micropores configured to allow air contained within the foam to escape when the foam board is compressed and / or configured to prevent the ingress of moisture into the foam.

2. 2. The vehicle structure (1) of claim 1, wherein the foam plate (2) further comprises holes (7) opening on one side of the foam plate or penetrating the foam plate from one side to the other, the holes being configured to allow air contained in the foam to escape when the foam plate is compressed.

3. 3. A vehicle structure (1) as claimed in claim 1 or 2, further comprising a portion in which the foam plate (2) is located near the rear of the vehicle and has a surface with holes (8) configured to expel air contained in the foam when the foam plate is compressed.

4. 4. A vehicle structure (1) as claimed in any one of claims 1 to 3, wherein the foam plate (2) is compressed between the floor (3) and the battery tray (4) by a compression ratio of 20% to 40%, for example 30% to 40%.

5. A vehicle structure (1) as described in any one of claims 1 to 4, wherein the thickness of the foam plate (2) when compressed at a compression rate of 30% of the foam plate is equal to or substantially equal to 10 mm or more and 20 mm or less, for example 13 mm or more and 14 mm or less, for example 13 mm.

6. 6. The vehicle structure (1) according to any one of the preceding claims, wherein the foam plate (2) comprises polyurethane foam.

7. 7. A vehicle structure (1) according to any one of the preceding claims, wherein the foam is a foam with a cell size smaller than 2 mm.

8. A vehicle (5), for example a hybrid vehicle or an electric motor vehicle, comprising a structure (1) according to any one of claims 1 to 7.

9. A method for assembling a vehicle structure (1), comprising the steps of: - drilling holes in the foam plate (2), - placing said foam plate (2) between the floor (3) of the vehicle and a battery tray (4) of the vehicle; - compressing said foam board (2) to a compression ratio of between 20% and 40%; - fixing said battery tray (4) to said floor (3) so that said foam plate (2) remains compressed to a compression ratio of 20% to 40%; Including, The method of claim 1, wherein the surface layer of the foam plate (2) comprises micropores configured to allow air contained within the foam to escape when the foam plate is compressed and / or configured to prevent the ingress of moisture into the foam.

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