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] DESCRIPTION

[0002] Title: Architecture for mounting an electrodynamic transducer in an interior compartment of a motor vehicle

[0003] The invention relates to an architecture for mounting an electrodynamic transducer in an interior compartment of a motor vehicle.

[0004] It is known to produce an architecture for mounting an electrodynamic transducer in an interior compartment - passenger compartment or luggage compartment - of a motor vehicle, said architecture comprising as one moves downwards:

[0005] • a vibrating structure plate with a Young's modulus of between 10 8 and 10 9 Pa,

[0006] • 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,

[0007] • a decoupling frame for said elastically compressible foam plate, said plate being fixed by its periphery to said frame,

[0008] • a floor sheet of said vehicle.

[0009] The use of a transducer fixed on a vibrating plate, instead of a loudspeaker, allows space and weight to be saved in the vehicle.

[0010] However, an architecture such as described above:

[0011] • does not allow optimal transmission of low frequencies within the passenger compartment,

[0012] • does not provide good insulation against vehicle rolling noise.

[0013] The invention aims to overcome these drawbacks. To this end, the invention proposes an architecture for mounting an electrodynamic transducer in an interior compartment of a motor vehicle, said architecture comprising, as one moves downwards:

[0014] • a vibrating structure plate with a Young's modulus of between 10 8 and 10 9 Pa,

[0015] • at least one electrodynamic transducer fixed under said plate,

[0016] • a decoupling frame for said elastically compressible foam plate, said plate being fixed by its periphery to said frame,

[0017] • a floor sheet of said vehicle, said architecture also having the following characteristics:

[0018] • said decoupling frame has an increasing stiffness as one moves away from said plate,

[0019] • it further comprises, successively interposed from top to bottom between said decoupling frame and said sheet: o a rigid holding frame receiving said decoupling frame, said holding frame having a Young's modulus of between 10 8 and 10 9Pa, or a plurality of base pads of said support frame, said pads having a Young's modulus of between 10 5 and 10 6 Pa, said pads and frames delimiting a main cavity extending under said plate, o a porous decoupling and absorption layer receiving said pads, said layer being elastically compressible and with open porosity, the Young's modulus of said layer being between 10 4 and 10 5 Pa, o an annex cavity extending around said pads and communicating with said main cavity via the inter-pad spaces, so as to define an extended cavity. In this description, the terms of positioning in space (top, bottom, upper, vertical, under, above, ...) are taken in reference to the architecture in place in the vehicle.

[0020] With the proposed layout:

[0021] • the fact that the decoupling frame has an increasing stiffness as one moves away from the plate, makes it possible to achieve vertical vibration decoupling of the plate while holding it firmly in place to limit oscillations in other directions,

[0022] • the holding frame acts as a reinforcement for the decoupling frame to maintain it as best as possible in its geometry without stress,

[0023] • the pads support the decoupling frame while helping to minimize the transmission of vibrations to the sheet metal,

[0024] • the porous layer with open porosity combined with the air space contained in the main cavity between the plate and the sheet metal makes it possible to achieve, according to a “double wall” principle, acoustic insulation against rolling noise; in addition, the porous layer contributes to the decoupling of the plate,

[0025] • the presence of the additional cavity makes it possible to define the extended cavity which, due to its large size, is conducive to optimizing the reproduction of low frequencies.

[0026] Other features and advantages of the invention will appear in the following description, given with reference to the attached figures, in which: [Fig.1] is a partial exploded schematic perspective view of an architecture according to one embodiment,

[0027] [Fig. 2] is a partial schematic view, in vertical section between two pads, of the architecture of Figure 1 according to one embodiment. With reference to the figures, an architecture 1 for mounting an electrodynamic transducer in an interior compartment of a motor vehicle is described, said architecture comprising as one moves downwards:

[0028] • a plate 6 with a vibrating structure having a Young's modulus of between 10 8 and 10 9 Pa,

[0029] • at least one electrodynamic transducer 3 fixed under said plate,

[0030] • a decoupling frame 4 of said elastically compressible foam plate, said plate being fixed - for example by gluing - by its periphery 5 on said frame,

[0031] • a floor plate 2 of said vehicle, said architecture also having the following characteristics:

[0032] • said decoupling frame has an increasing stiffness as one moves away from said plate,

[0033] • it further comprises, successively interposed from top to bottom between said decoupling frame and said sheet: o a rigid holding frame 7 receiving said decoupling frame, said holding frame having a Young's modulus of between 10 8 and 10 9Pa, or a plurality of base pads 8 of said holding frame, said pads having a Young's modulus of between 10 5 and 10 6 Pa, said pads and frames delimiting a main cavity 9 extending under said plate, o a porous decoupling and absorption layer 10 receiving said pads, said layer being elastically compressible and with open porosity - being for example made of foam or felt -, the Young's modulus of said layer being between 10 4 and 10 5 Pa, o an annex cavity 11 extending around said pads and communicating with said main cavity via the inter-pad spaces 12, so as to define an extended cavity. According to various embodiments, the decoupling frame 4 may be made of closed-cell ethylene propylene diene monomer (EPDM) foam and / or open-cell polyurethane foam.

[0034] According to the embodiment shown, the decoupling frame 4 has a stiffness varying discontinuously, said frame comprising a plurality of elementary decoupling frames 13 made of elastically compressible foam stacked on top of each other, the Young's modulus of said elementary frames increasing as one moves away from the plate 6 and being between 10 4 and 10 6 Pa.

[0035] According to an embodiment not shown, the decoupling frame 4 is in one piece, said frame having a Young's modulus which increases continuously as one moves away from the plate 6, said modulus being between 10 4 and 10 6 Pa.

[0036] Such a variation in 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.

[0037] According to another embodiment not shown, the decoupling frame 4 is a single piece, said frame having in the upper part of its thickness material recesses making it possible to reduce its stiffness (and therefore to reduce its apparent Young's modulus).

[0038] 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.

[0039] According to another embodiment, the upper face of the decoupling frame 4 has bosses made from the material of said frame, the recesses being formed by the inter-boss spaces. According to one embodiment, the pads 8 have a relative stress-strain characteristic in vertical compression CC40, measured according to the ISO 3386 / 2 standard in force on the date of filing of the application, greater than 10 kPa.

[0040] According to the embodiment shown, the pads 8 are associated by their upper end with a support frame 14, in particular made of the same material as said pads, said support frame receiving the holding frame 7.

[0041] In particular, the pads 8 and the support frame 14 may be in one piece.

[0042] According to one embodiment, the pads 8 have open porosity, so as to achieve acoustic absorption.

[0043] According to one embodiment, the pads 8 are based on elastically compressible foam flakes connected to each other by two-component fibers comprising a high-temperature fusible core and a lower-temperature fusible sheath, the connection between said flakes having been achieved by melting said sheath.

[0044] The advantage of such a material is that it has a high load-bearing capacity (static compressibility at large deformations) and a low Young's modulus at small deformations.

[0045] Bi-component fibers, for example, comprise a core made of polyethylene terephthalate (PET) and a sheath made of polyethylene terephthalate modified to lower its melting point.

[0046] As shown in Figure 2, the annex cavity 11 comprises a space 22 located between a carpet 15 covering the floor of the vehicle and the sheet metal 2, said carpet being spaced from said sheet metal by spacing means 16 decoupled from said sheet metal by a decoupling means 17.

[0047] As shown in Figure 2, the mat 15 also extends over the plate 6. According to a variant not shown, a cutout may be provided in the mat 15 along the periphery of the plate 6, so as not to create a coupling between the part of said mat surrounding said plate and said plate.

[0048] Optionally, a sheet of very flexible material, such as a non-woven fabric, may be placed at the cutout, so as to ensure continuity of appearance of the carpet 15.

[0049] According to the embodiment shown, the carpet 15 is placed on a raised floor 18 comprising a layer of compressible foam 19 and a tray 20 made of molded plastic material for receiving said layer, said tray being provided with feet 21 produced by molding forming spacing means 16, the annexed cavity 11 comprising the space 22 extending between said feet.

[0050] According to the embodiment shown, the decoupling means 17 comprises the porous layer 10 extending into the annex cavity 11, the feet 21 being placed on said layer.

[0051] According to one embodiment, the plate 6 is arranged under a seat, so as to be protected from the passengers' feet pressing on it.

Claims

DEMANDS 1. Architecture (1) for mounting an electrodynamic transducer in an interior compartment of a motor vehicle, said architecture comprising, as one moves downwards: • a vibrating structure plate (6) having a Young's modulus between 10 8 and 10 9 Pa, • at least one electrodynamic transducer (3) fixed under said plate, • a decoupling frame (4) for said elastically compressible foam plate, said plate being fixed by its periphery (5) to said frame, • a floor plate (2) of said vehicle, said architecture being characterized in that: • 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: o a rigid retaining frame (7) receiving said decoupling frame, said retaining frame having a Young's modulus between 10 8 and 10 9 Pa, or a plurality of supports (8) for the base of said support frame, said supports having a Young's modulus between 10 5 and 10 6 Pa, said studs and frames delimiting a main cavity (9) extending under said plate, or a porous decoupling and absorption layer (10) receiving said studs, said layer being elastically compressible and open-porosity, the Young's modulus of said layer being between 10 4 and 10 5 Pa, or an accessory cavity (11) extending around said plots and communicating with said main cavity through inter-plot spaces (12), so as to define an extended cavity.

2. An architecture 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) made of elastically compressible foam stacked one on top of the other, the Young's modulus of said elementary frames increasing with distance from the plate (6) and being between 10 4 and 10 6 Pa.

3. Architecture according to claim 1, characterized in that the decoupling frame (4) is a single piece, said frame having a Young's modulus that increases continuously with distance from the plate (6), said modulus being between 10 4 and 10 6 Pa.

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

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

6. Architecture according to any one of the preceding claims, characterized in that the pads (8) are associated by their upper end to a support frame (14) receiving the retaining frame (7).

7. Architecture according to any one of the preceding claims, characterized in that the pads (8) have an open porosity, so as to achieve acoustic absorption.

8. Architecture according to any one of the preceding claims, characterized in that the pads (8) are based on elastically compressible foam flakes linked together by two-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. Architecture according to any one of the preceding claims, characterized in that the ancillary cavity (11) comprises a space (22) situated between a mat (15) covering the vehicle floor 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).

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