FR2777845A1 - APRON SOUNDPROOFER FOR MOTOR VEHICLE - Google Patents

Abstract

It is an apron sound absorber extending across the vehicle and, axially, between the fan unit (13) and the passenger compartment (3), the sound absorber comprising a portion swollen towards the passenger compartment, substantially in manhole cover, and locally reserving at least one passage (33) for air circulation ducts (15a, 15b, 15d) connected to the fan unit and communicating, from inside the dashboard (7), with the passenger compartment, for ventilation, demisting, heating and / or air conditioning thereof.

Description

The invention relates to the field of making panels or rugs

  soundproofing having good sound attenuation qualities as a "noise barrier" for use in particular in the automotive sector. Different complexes comprising several materials have already been used in this field to constitute insulation structures or

sound absorption.

  Thus, in US-A-5 266 143 is proposed a panel or carpet used as soundproofing of the apron, between the engine compartment and the passenger compartment "or passenger compartment" of a vehicle, or even as carpet

of floor for this cabin.

  In US-A-5 266 143, the soundproofing may in particular comprise porous textile fibers impregnated with a plastic resin coupled to one or more layers of bituminous material incorporating fillers (such as CaCl, or BaSO), as well as a layer of foam or more generally a layer of porous material, such as

polyurethane or EPDM.

  Furthermore, in DE-A44 40 973, it is known to have a resistant separation between the engine compartment and the passenger compartment of a vehicle, this separation being in the form of a panel extending over the entire width of the passenger compartment having a bulge defining a "U" section opening towards the engine compartment, to constitute one or more chambers adapted to receive accessories, such as

  particular than an air conditioning system (air conditioning).

  The object of the present invention is to provide equipment to be placed inside the vehicle, generally having the form of a carpet or a panel to constitute in particular an effective sound insulation between the engine compartment and the passenger compartment, with soundproofing power that is particularly effective for the group

  fan motor located near the engine compartment.

  It will now be noted that the term "motorized fan unit" means motorized ventilation which makes it possible, in a vehicle, to distribute air inside the vehicle (ventilation and demisting in particular) and / or provide air conditioning or heating in the passenger compartment. According to the invention, a synthetic soundproofing apron is thus proposed extending transversely over the width of the vehicle, and "axially" between the fan unit and the passenger compartment, the soundproofing comprising a portion bulged towards the passenger compartment, substantially opposite the fan unit, and locally reserving at least one passage to one (or more) air circulation duct (s) connected to the fan unit and communicating, through the interior of the dashboard, with the cockpit, for

  ventilation, demisting and / or air conditioning thereof.

  Thus, it will be possible to place this soundproofing optimally vis-à-vis the engine compartment, without hampering the distribution of air to the passenger compartment, or the integration of other parts or

surrounding elements.

  To favor this adaptation of the insulating mat of the invention to the configuration of this generally required zone, and to also facilitate the installation of this mat, it is advised that it comprises a separate upper part and a lower part. , leaving between them, or through at least one of them, substantially opposite the fan unit, a

  space for said passage of said air circulation duct (s).

  Still to favor this search for space limitation, in combination with high-performance acoustic insulation, another characteristic provides that the upper and lower parts of the carpet are applied substantially at least locally against the air duct (s), in particular at the location of said passage, the two parts of the carpet preferably overlapping, at least in part (in projection in a vertical plane), the lower part being able to further advance, opposite the fan unit, more towards the passenger compartment that the upper part which can then be locally essentially applied against this fan unit, the lower part of the carpet closely covering at least one additional air distribution duct towards the rear of the passenger compartment, passing along the floor of the vehicle . Again to promote soundproofing, but also for questions of costs and installation conditions, an additional feature of the invention provides that the carpet presented above can, below, extend above the floor of the vehicle, then defining

  a floor mat for (at least part of) the passenger compartment.

  Thus, in a single operation, it is possible to lay both the floor mat and the sound insulation means between the passenger compartment and the

engine compartment.

  With regard to the constitution of the carpet of the invention, it is advised that at least its upper part include a porous sound-absorbing layer and an absorbent septum made of charged thermoplastic material, denser than the porous layer, the latter being located towards the engine compartment (or the fan assembly) and the septum loaded towards the passenger compartment. Optionally, the lower part of the carpet can be of a different constitution and include only at least one layer

  sound absorbing porous lined, above it, by a carpet.

  A more detailed description of the invention will now be

  presented, with reference to the accompanying drawings in which: - Figure 1 is a schematic view, in axial longitudinal section, along the line marked I - I in Figure 2 or in Figure 3, - Figure 2 is a schematic view, in perspective, in particular of the upper part of the carpet of the invention (in solid line), - Figure 3 is, still in schematic perspective view, a view representing in particular the lower part of the carpet (in solid line), - FIG. 4 reproduces FIG. 1, with a few modifications,

  - And Figure 5 reproduces Figure 2, with some modifications.

  In FIG. 1, the mark 1 applies to the engine compartment, the mark 3 to the passenger compartment and the mark 5 to the windshield. In 7, we find the dashboard and in 9, the central console where we conventionally find the gearshift lever (not shown).

  In 11, the vehicle floor plate has been shown diagrammatically.

  As can be seen, the fan assembly identified as a whole 13 is located near the engine compartment 1, behind the

dashboard 7.

  For air distribution, whether it is air intended for demisting the windshield 5, ventilating the passenger compartment, heating or even air conditioning thereof, it is of the fan unit 13 which all the air ducts under consideration leave. In this case, we see represented three conduits: a demisting conduit 15a which ends in an orifice 17a close to the windshield 5, a second conduit 15b which ends at the location of the front ventilation orifices 17b and a third conduit 15c which runs the

  along the floor, in this case under the carpet 30b.

  The fan unit 13 comprises in particular a ventilation device 19, a heating or air conditioning group 21 and an air distribution box 23 which communicates directly with the

conduits 15a, 15b, 15c.

  Thus constituted, the fan unit 13 advances under the dashboard 7, just above the floor 11. It is moreover fixed or held in place in particular on a rigid crossmember (generally metallic) consisting of a bar of reinforcement 25 to which is

  usually also attached the dashboard 7.

  To isolate the passenger compartment area 3 from the engine compartment 1, and to isolate this passenger compartment in particular from the noisy fan unit, a synthetic panel or carpet identified as a whole 30 has been put in place , over the fan assembly, while leaving locally through it a passage 33 allowing the tubular trunk 15d connected to the air box 23 to pass through the noise reduction mat 30, before being

  branch (in this case, ducts 15a, 15b).

  Thus, this opening 33 will allow the air to reach the passenger compartment passing through the interior of the dashboard, while at least one other duct, such as the duct 15c, may remain under the carpet 30 and lead into the passenger compartment only further back, far enough behind the

the dashboard.

  In a preferred embodiment, rather than opening the passage 33 in a one-piece carpet structure, it is advisable to produce the carpet 30, at the location of the covering of the fan unit 13, in two parts, an upper part 30a and a lower part 30b, the separation taking place at the right of the connection 15d, therefore of the passage 33 which then exists,

  in depth, between the two carpet parts.

  As can be seen in FIGS. 2 and 3, the soundproofing mat 30 extends transversely over the entire width 1 of the vehicle and in this case has, in the central part, that is to say above the housing area of the fan unit 13 and opposite the console 9, a bulge which has been identified 35a in FIG. 2 and 35b in FIG. 3,

  since here is shown a carpet in two parts.

  This hollow central bulge 35a / 35b which advances towards the interior of the passenger compartment relative to the rest of the surface of the carpet constitutes a box open in the direction of the engine compartment and coming to marry or coat the

fan unit 13.

  Away from this bulge, the mat is essentially flat, in sections. Its means of attachment to the vehicle chassis have not been shown. In FIG. 2, it can be seen that the upper part 30a is essentially vertical and comprises two vertical side skirts 37, 39, oriented towards the rear of the vehicle, and a long inclined transverse upper flap 41, running along the base of the screen. -brise 5, just below the edge

  upper front of dashboard 7 (see figure 1).

  In FIG. 3, it can also be seen that in the present case the lower part 30b of the mat has first, apart from the bulge 35b and in the vertical continuity of the bottom of the upper part 30a (shown in phantom line), vertical section which descends along the separation zone

  between the passenger compartment and the engine compartment until reaching the floor 11.

  In this version, the lower belt 30b is one piece with the

passenger compartment floor mat.

  In 45, the opening has been identified, upwards and forwards, which exists in the central bulge 35b, and one can easily imagine the complementary opening (not marked) which exists opposite the

bulge 35a in FIG. 2.

  To perfect the sound insulation, the two transverse edges opposite the upper and lower parts of the carpet partially overlap, as can be seen in particular in FIG. 2 where the height of the overlap has been identified, where the two carpet borders are

applied against each other.

  In Figure 1, where we also see this height b we have also identified in 47a and 47b (see also Figure 2) the upper and lower edges respectively of the carpet parts 30b and 30a which overlap at a distance, since this is where we find passage 33 for air

  walking inside the dashboard.

  Given the slightly sloping arrangement of this overlap by the edges 47a, 47b, it is possible to obtain good sound attenuation, despite the opening 33, all the more so as these edges are advantageously applied against the structural parts which they surround. , in this case the section 15d (edge 47a) and the crosspiece 25 (edge 47b), this crosspiece itself coming into contact with the conduit 15d. By this partial covering and by this maintenance of the mat plated against functional elements to be phonically insulated (for example by means of a strapping band), it is

  further reduces the transmission of unwanted noise to the passenger compartment.

  At least the upper part of the carpet 30 (in this case, the part 30a) will advantageously comprise a porous sound-absorbing layer 40 ((located on the side of the engine compartment) and an absorbent septum made of material.

  thermoplastic 42 located towards the passenger compartment.

  The porous soundproofing layer 40 can be a felt or a foam, in particular. It can be a polyester felt or a felt

  phenolic, or polyurethane foam.

  The septum sheet 42 is made of a thermoplastic material incorporating fillers and denser than the porous layer 40. This septum can in particular be made of a plastic resin containing a high rate of inorganic fillers with high molecular weight, a mixture of polyolefins or EPDM polymers, or alternatively be presented as a "heavy mass" as described in

FR-A-2 733 933.

  The lower part 30b can be constituted in the same way.

  However, it can also be provided that the septum is replaced by a conventional vehicle floor mat or a carpet 44, the latter covering the layer.

  porous lower 40 already described (solution illustrated in Figure 1).

  It can also be provided that the upper part of the carpet (such as

  part 30a) has a fire barrier layer covering layers 42 or 40.

  It may in particular be a fire retardant coating comprising a copolymer of vinylidene fluoride and hexafluoropropene then placed over the porous layer 40, to form a fire barrier facing the

engine compartment 1.

  Figure 4 differs from Figure 1 in that the passage (marked here 33 ') for the air duct 15d is formed through the upper part 30a of the carpet. It is a large opening open frontally and laterally,

  as can be seen in Figure 5.

  It is also "covered" frontally and laterally, at a distance, by the extreme upper portion 47a of the lower part of the carpet 30b which forms

  as well as a sound screen for the passenger compartment.

  Lower than the passage 33 ', the carpet 30a extends in front of the element 23 of the fan unit, so that there is a double sound screen there for the passenger compartment. Preferably, this portion of carpet will be

pressed against element 23.

  We will note the judicious position of this double phonic screen, in the lower part of the dashboard area, where, on either side of the center console area, this dashboard is interrupted at mid-height, substantially at the level of the upper portion 47a of the carpet 30b. Such a double screen effectively replaces the "noise barrier" created above by a single thickness of carpet 30a and by the box formed by the dashboard. It has thus been understood that in the version of FIGS. 4 and 5, the part 30a descends lower than in the version of FIGS. 1 to 3 (possibly

  substantially to the floor level).

  As a last alternative, the passage for the air duct (s)

  could be arranged through the raised upper part of the lower belt 30b.

Claims (8)

Claims   1. Apron sound absorber extending transversely across the width of the vehicle and, axially, between the fan unit (13) and the passenger compartment (3), the sound absorber comprising a portion (35a, 35b) swollen towards the passenger compartment, substantially opposite the fan unit, and locally reserving at least one passage (33) to one (s) air circulation duct (s) (15a, 15b, 15d) connected (s) to the fan unit and communicating, by the interior of the dashboard (7), with the passenger compartment, for ventilation,   demisting, heating and / or air conditioning thereof.   2. Soundproofing according to claim 1, characterized in that it comprises a separate upper part (30a) and a lower part (30b), leaving between them, or through at least one of them, substantially opposite the fan unit, a space (33) for the   passage of said air circulation duct (s).   3. Soundproofing according to claim 2, characterized in that, essentially opposite the fan unit (13), the lower part (30b) of the soundproofing advances more towards the passenger compartment (3) than the upper part (30a) which is at least locally substantially applied against the fan assembly, the lower part closely covering at least one additional air distribution duct (15c) towards the rear of   the passenger compartment passing along the floor (11) of the vehicle.   4. Soundproofing according to claim 2 or claim 3, characterized in that its upper and / or lower parts (30a, 30b) are applied against the air duct (s) at the location of said passage (33 ) for   provide an acoustic seal.   5. Soundproofing according to any one of claims 2 to 4,   characterized in that in vertical projection, the two parts of the soundproofing overlap at least locally, thus creating a double thickness isolation for the passenger compartment.   6. Soundproofing according to any one of claims I to 5,   characterized in that at the bottom the soundproofing extends above the floor   (11) of the vehicle, then defining a floor mat for the passenger compartment.   7. Soundproofing according to any one of the claims   above, characterized in that it comprises a porous sound-absorbing layer (40) and an absorbing septum (42) of charged thermoplastic material, denser than the porous layer, the latter being located towards the   engine compartment (1) and the septum loaded towards the passenger compartment.   8. Soundproofing according to any one of claims 2 to 6,   characterized in that: - the upper part (30a) of the soundproofing comprises a porous soundproofing layer (40) and an absorbing septum (42) of charged thermoplastic material, denser than the porous layer, the latter being located towards the compartment motor (1) and the septum loaded towards the passenger compartment, and - the lower part (30b) of the soundproofing comprises at least one porous soundproofing layer (40) lined, above it, by a carpet (44).