Construction for mounting an electrodynamic transducer in a passenger compartment of a motor vehicle

Abstract

The invention relates to a construction (1) for mounting an electrodynamic transducer in the passenger compartment of a motor vehicle, the construction comprising a plate (6) having a vibrating structure, at least one electrodynamic transducer (3) attached to the plate, a decoupling frame (4) of increasing stiffness, and a vehicle floor pan (2), and, between the decoupling frame and the floor pan: a rigid holding frame (7) that receives the decoupling frame; a plurality of feet (8) for the base of the holding frame, delimiting a main cavity (9); a porous decoupling and absorption layer (10); and an adjoining cavity (11) extending around the feet and communicating with the main cavity through the spaces (12) between the feet.

Description

[0001] The invention relates to a mounting architecture for an electrodynamic transducer in an interior compartment of a motor vehicle.

[0002] It is known to create a mounting architecture for an electrodynamic transducer in an interior compartment – ​​passenger compartment or luggage compartment – ​​of a motor vehicle, said architecture comprising, as one moves downwards: a vibrating structure plate having a Young's modulus between 10⁸ and 10⁹ Pa, at least one electrodynamic transducer fixed under said plate, in order to allow the emission of a sound signal, such as music, within the passenger compartment of said vehicle, a decoupling frame of said plate made of elastically compressible foam, said plate being fixed by its periphery to said frame, a floor plate of said vehicle.

[0003] Using a transducer mounted on a vibrating plate, instead of a loudspeaker, saves space and weight in the vehicle. US2021 / 352390 describes a mounting architecture for an electrodynamic transducer in an interior compartment of a motor vehicle.

[0004] However, an architecture such as the one described above: does not allow optimal transmission of low frequencies within the passenger compartment, does not ensure good insulation against vehicle rolling noise.

[0005] The invention aims to overcome these drawbacks.

[0006] To this end, the invention proposes a mounting architecture for an electrodynamic transducer in an interior compartment of a motor vehicle, said architecture comprising, as one moves downwards: a vibrating structure plate having a Young's modulus between 10⁸ and 10⁹ Pa, at least one electrodynamic transducer fixed under said plate, a decoupling frame for said plate made of elastically compressible foam, said plate being fixed by its periphery to said frame, a floor plate for said vehicle, said architecture also presents the following characteristics: said decoupling frame exhibits increasing stiffness with distance from said plate; it further comprises, interposed successively from top to bottom between said decoupling frame and said plate: ∘ a rigid support frame receiving said decoupling frame, said support frame having a Young's modulus between 10⁸ and 10⁹ Pa, ∘ a plurality of base pads for said support frame, said pads having a Young's modulus between 10⁵ and 10⁶ Pa, said pads and frames defining a main cavity extending under said plate, ∘ a porous decoupling and absorption layer receiving said pads, said layer being elastically compressible and open-porous, the Young's modulus of said layer being between 10⁴ and 10⁵ Pa, ∘ an auxiliary cavity extending around said pads and communicating with said main cavity by the inter-plot spaces, so as to define an extended cavity.

[0007] In this description, the terms of positioning in space (up, down, superior, vertical, under, above, ...) are taken in reference to the architecture in place in the vehicle.

[0008] With the proposed layout: The fact that the decoupling frame has increasing stiffness as you move away from the plate allows for vertical vibration decoupling of the plate while holding it firmly in place to limit oscillations in other directions; the support frame acts as reinforcement for the decoupling frame to maintain it in its unstressed geometry as best as possible; the pads support the decoupling frame while contributing to minimizing the transmission of vibrations to the sheet metal; the open-porosity porous layer combined with the air space contained in the main cavity between the plate and the sheet metal allows for acoustic insulation against rolling noise, according to a "double wall" principle;Furthermore, the porous layer contributes to the decoupling of the plate; the presence of the auxiliary cavity allows for the definition of the extended cavity which, due to its extended size, is conducive to optimizing the reproduction of low frequencies.

[0009] Other features and advantages of the invention will become apparent in the following description, made with reference to the accompanying figures, in which: [ Fig.1 ] is a schematic view in partial exploded perspective of an architecture according to a realization, [ Fig.2 ] is a partial schematic view, in vertical section between two plots, of the architecture of the figure 1 according to a particular embodiment.

[0010] With reference to the figures, we describe an architecture 1 for mounting an electrodynamic transducer in an interior compartment of a motor vehicle, said architecture comprising, as we move downwards: a vibrating structure plate 6 having a Young's modulus between 10⁸ and 10⁹ Pa, at least one electrodynamic transducer 3 fixed under said plate, a decoupling frame 4 of said plate made of elastically compressible foam, said plate being fixed - for example by gluing - by its periphery 5 to said frame, a floor plate 2 of said vehicle, said architecture also presents the following characteristics: said decoupling frame exhibits increasing stiffness as one moves away from said plate; it further comprises, interposed successively from top to bottom between said decoupling frame and said sheet metal: ∘ a rigid support frame 7 receiving said decoupling frame, said support frame having a Young's modulus between 10⁸ and 10⁹ Pa, ∘ a plurality of base pads 8 for said support frame, said pads having a Young's modulus between 10⁵ and 10⁶ Pa, said pads and frames delimiting a main cavity 9 extending under said plate, ∘ a porous decoupling and absorption layer 10 receiving said pads, said layer being elastically compressible and open-porous - being, for example, made of foam or felt -, the Young's modulus of said layer being between 10⁴ and 10⁵ Pa,• an auxiliary cavity 11 extending around said studs and communicating with said main cavity via the inter-stud spaces 12, so as to define an extended cavity.

[0011] According to various embodiments, the decoupling frame 4 can be made of closed-cell ethylene propylene diene monomer (EPDM) foam and / or open-cell polyurethane foam.

[0012] According to the embodiment shown, the decoupling frame 4 has a discontinuously varying stiffness, said frame comprising a plurality of elementary decoupling frames 13 made of elastically compressible foam stacked one on top of the other, the Young's modulus of said elementary frames increasing as one moves away from the plate 6 and being between 10⁴ and 10⁶ Pa.

[0013] According to an embodiment not shown, the decoupling frame 4 is monobloc, said frame having a Young's modulus increasing continuously as one moves away from the plate 6, said modulus being between 10⁴ and 10⁶ Pa.

[0014] Such a variation of the Young's modulus can for example be obtained by increasing the density of the material constituting the decoupling frame 4 as one moves away from the plate 6.

[0015] According to another embodiment not shown, the decoupling frame 4 is a single piece, the frame having in the upper part of its thickness material recesses allowing to reduce its stiffness (and therefore to reduce its apparent Young's modulus).

[0016] According to one embodiment, the recesses can be made by holes made in the upper part of the thickness of the decoupling frame 4, said holes opening onto the upper face of said frame.

[0017] According to another embodiment, the upper face of the decoupling frame 4 has bosses made of material from said frame, the recesses being formed by the inter-boss spaces.

[0018] According to one embodiment, the 8 pads exhibit a relative stress-strain characteristic in vertical compression CC 40, measured according to the ISO 3386 / 2 standard in force at the date of filing of the application, greater than 10 kPa.

[0019] According to the embodiment shown, the studs 8 are associated at their upper end with a support frame 14, in particular made of the same material as said studs, said support frame receiving the retaining frame 7.

[0020] In particular, the 8 studs and the 14 support frame can be one piece.

[0021] According to one design, the 8 pads have an open porosity, in order to achieve acoustic absorption.

[0022] According to one embodiment, the pads 8 are based on elastically compressible foam flakes connected together by bi-component fibers comprising a high-temperature fusible core and a lower-temperature fusible sheath, the bond between said flakes having been made by melting said sheath.

[0023] The advantage of such a material is that it exhibits high load-bearing capacity (static compressibility at large deformations) and a low Young's modulus at small deformations.

[0024] Bi-component fibers include, for example, a polyethylene terephthalate (PET) core and a polyethylene terephthalate sheath modified to lower its melting point.

[0025] As depicted in figure 2 , the ancillary cavity 11 includes a space 22 located between a mat 15 covering the floor of the vehicle and the sheet metal 2, said mat being separated from said sheet metal by spacing means 16 decoupled from said sheet metal by a decoupling means 17.

[0026] As depicted in figure 2 , mat 15 also extends onto plate 6.

[0027] According to an unrepresented variant, a cutout may be provided in the mat 15 along the periphery of the plate 6, so as not to create coupling between the part of said mat surrounding said plate and said plate.

[0028] Optionally, a sheet of very flexible material, such as a non-woven fabric, can be placed at the cut, so as to ensure continuity of appearance of the carpet 15.

[0029] According to the embodiment shown, the carpet 15 is placed on a false floor 18 comprising a layer of compressible foam 19 and a platform 20 made of molded plastic material for receiving said layer, said platform being provided with feet 21 made from molding forming spacing means 16, the adjoining cavity 11 comprising the space 22 extending between said feet.

[0030] According to the embodiment shown, the decoupling means 17 comprises the porous layer 10 extending into the ancillary cavity 11, the feet 21 being placed on said layer.

[0031] According to one design, plate 6 is positioned under a seat, so as to be protected from the pressure of passengers' feet.

Claims

1. Construction (1) for mounting an electrodynamic transducer in a passenger compartment of a motor vehicle, said construction comprising upon directing downwards: • a plate (6) having a vibrating structure with a Young's modulus of between 108 and 109 Pa, • at least one electrodynamic transducer (3) attached under said plate, • a decoupling frame (4) for said plate, that is made of elastically compressible foam, said plate being attached by its periphery (5) to said frame, • a floor pan (2) of said vehicle, said construction being characterized in that: • said decoupling frame has increasing stiffness upon distancing from said plate, • it further comprises, interposed successively from top to bottom and between said decoupling frame and said floor pan: ∘ a rigid holding frame (7) receiving said decoupling frame, said holding frame having a Young's modulus of between 108 and 109 Pa, ∘ a plurality of feet (8) for the base of said holding frame, said feet having a Young's modulus of between 105 and 106 Pa, said feet and frames delimiting a main cavity (9) extending under said plate, ∘ a porous decoupling and absorption layer (10) receiving said feet, said layer being elastically compressible and of open porosity, the Young's modulus of said layer being between 104 and 105 Pa, ∘ an adjoining cavity (11) extending around said feet and communicating with said main cavity through the spaces (12) between said feet, so as to define an extended cavity.

2. Construction according to claim 1, characterized in that the decoupling frame (4) has a discontinuously varying stiffness, said frame comprising a plurality of elementary decoupling frames (13) of elastically compressible foam stacked one on top of the other, the Young's modulus of said elementary frames increasing upon distancing from the plate (6) and being between 104 and 106 Pa.

3. Construction according to claim 1, characterized in that the decoupling frame (4) is made in one piece, said frame having a Young's modulus that increases continuously upon distancing from the plate (6), said modulus being between 104 and 106 Pa.

4. Construction according to claim 1, characterized in that the decoupling frame (4) is made in one piece, said frame having material recesses in the upper part of its thickness.

5. Construction according to any of the preceding claims, characterized in that the feet (8) have a relative vertical compressive stress-strain characteristic CC40, measured according to ISO 3386 / 2 standard, greater than 10 kPa.

6. Construction according to any of the preceding claims, characterized in that the feet (8) are associated by their upper end with a support frame (14) receiving the holding frame (7).

7. Construction according to any of the preceding claims, characterized in that the feet (8) have an open porosity, so as to achieve sound absorption.

8. Construction according to any of the preceding claims, characterized in that the feet (8) are based on elastically compressible foam flakes bonded together by bi-component fibers comprising a high-temperature fusible core and a lower-temperature fusible sheath, the bond between said flakes having been achieved by melting said sheath.

9. Construction according to any of the preceding claims, characterized in that the adjoining cavity (11) comprises a space (22) located between a mat (15) covering the vehicle floor and the pan (2), said mat being spaced from said sheet by spacer means (16) decoupled from said pan by a decoupling means (17).

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