FR2923193A1 - Cowl shell for motor vehicle, has detachable fixation unit fixing detachable front wall on collector lower wall for assuring compression of sealed element, where sealed element is interposed between lower wall and detachable front wall - Google Patents

Abstract

The shell (1) has a collector lower wall (7) fixed to a lower crossmember lower of support of a windscreen, and a detachable front wall (6) located under a hood. A cowl grid (4) is extended between the front wall and the windscreen. A sealed element (16) is interposed between the wall and the detachable front wall. A detachable fixation unit fixes the detachable front wall on the collector lower wall for assuring a compression of the sealed element, where the detachable front wall is realized in a plastic material.

Description

CANNING BOX WITH SEALING ELEMENT

The present invention relates to the technical field of motor vehicle awning boxes, placed between the engine compartment and the passenger compartment and intended to provide a dual function of admission of ventilation air of the passenger compartment and collection of water dripping rain on the windshield or the hood of the vehicle. In general, an awning box is delimited by at least one so-called collector bottom wall attached to the structure of the vehicle constituting the engine compartment. The structure of the vehicle most often includes in this area an apron separating the passenger compartment of the vehicle from the engine compartment and the structural elements defining the sides of the engine compartment. The collecting wall is generally attached to the side members. The awning box is also delimited by a front wall located under the hood and interposed between the engine compartment and the passenger compartment. This front wall is then fixed at least to the collector wall, this attachment being preferably provided so as to make the front wall removable to allow access to the various equipment that can be placed inside the canopy box. The awning box is finally bounded upwards by a canopy grille extending between the front wall, on which it is supported, and a seal disposed on the lower edge of the windshield. The awning grid then allows the admission of ventilation air from the passenger compartment while preventing the passage of large foreign bodies, such as tree leaves.

The vehicle awning boxes, as thus constituted, give full satisfaction with regard to the admission of outside air for the ventilation of the passenger compartment and the collection of rainwater, while preventing the entry of bulky objects in the ventilation circuit of the passenger compartment. However, it has become apparent that such awning boxes are not always able to limit the propagation of engine noise to the passenger compartment.

It therefore appeared the need for a new type of awning box that is able to limit the spread of this noise while ensuring the effectiveness of the primary functions of the box, or even increasing them.

In order to achieve these objectives, the invention relates to a motor vehicle awning box placed between, on the one hand, an engine compartment and a passenger compartment delimited in the front portion by a lower support rail of a windshield, the awning box being additionally limited by at least: a lower manifold wall attached to the lower rail, a removable front wall located under the hood, interposed between the engine compartment closing cover (C) and the collecting wall, and an awning grille extending between the front wall and the windshield. The vehicle awning box is characterized in that it comprises: at least one sealing element interposed between the collecting wall and the removable front wall, and detachably fixing means of the front wall. removable on the collector wall, adapted to provide compression of the sealing member.

The implementation of the sealing element interposed between the collector wall and the front wall, associated with fastening means which provide compression, reinforces the acoustic barrier constituted by the box. Indeed, the Applicant has had the merit of highlighting that the low acoustic performance of the caissons according to the prior art could be at least partly attributed to the irregularity of the contact existing between the front wall and the collector wall, thus leaving there are gaps in the sound distribution of the engine noise inside the box, itself connected to the ventilation circuit of the passenger compartment.

In addition, the sealing element interposed between the collector wall and the front wall reinforces the watertightness of the casing and prevents runoff of rainwater inside the engine compartment, thereby contributing to the watertightness of the latter, especially when the vehicle is stationary, and more particularly in an inclined position. The efficiency gain of the acoustic barrier, constituted by the box, obtained by the implementation of the compressed sealing element is all the more significant when the removable front wall and the collector wall are made of different materials. , such as for example metal for the collecting wall and a plastic material for the front wall. Indeed, it is not possible to achieve dimensional tolerances as accurate with plastic as with metal so that the sealing element allows effective correction of dimensional distortions at the interface. between the front wall and the collecting wall. According to one characteristic of the invention, the fastening means are adapted to compress the sealing element so that it has a compression height of between 65% and 85% of its height at rest.

Indeed, it has been found that such a level of compression makes it possible to obtain the optimum acoustic attenuation performance while maintaining a perfect watertightness. The Applicant has also found that the compression of the sealing element resulted in a non-linear rise in the attachment stresses of the front wall on the lower collector wall. It has been noted that the fixation stress is 15N / dm up to a compression of about 50%, then about 30N / dm for a compression of 66% and finally 70N / dm for a compression of 80%. In the latter case, the collector wall deforms in response to a higher rigidity of the front wall.According to the invention, the fixing means of the removable front wall on the collector wall can be made in any appropriate manner. According to a feature of the invention making it possible to reduce manufacturing and implementation costs, the fastening means are integral with the removable front wall and comprise a series of lugs which are each carried by an elastically deformable arm rigid to the removable front wall, and which are each intended to engage under a locking edge provided by the collector wall.

Such an embodiment of the fastening means allows a quick introduction of the removable front wall, without special tools. According to another characteristic of the invention, the fastening means are secured to the removable front wall and comprise a series of articulated hooks, which are each movable in rotation relative to the removable front wall and which are each intended to engage under a locking edge provided by the collector wall. According to the invention, the articulated hooks can be made of any suitable material, such as for example a suitable plastic material or a folded sheet metal sheet. Such an embodiment of the fastening means also allows rapid assembly without special tools of the front wall, and easy disassembly of the latter without risk of damage to the fastening means. According to yet another characteristic of the invention, the fastening means comprise a series of U-shaped clips, each of which has two branches connected by a core, an upper branch having, opposite the core, an end intended to come engage in a housing provided by the removable wall, while the other lower leg is intended to extend under a locking flange provided by the collector wall, the lower branch carrying an axis for receiving a movable locking lever between a clamping position and a loosened position, the lever having, at its attachment end on the axis of the clip, a cam configuration adapted to ensure a connection between the removable front wall and the collecting wall so as to compress the sealing element when the lever is in the clamping position. Such an embodiment makes it possible to ensure optimum control of the compression of the sealing element by the shape of the cam integrated in the locking lever. According to another characteristic of the invention to further increase the acoustic insulation performance of the awning box, the removable front wall comprises at its face facing the engine compartment, mounting studs of an acoustic screen.

According to the invention, the acoustic screen can be made in any suitable manner and, for example, comprise a hydrophobic and oleophobic topcoat and a heavy mass layer based on fibrous material, assembled and formed together by a thermoforming process.

In order to facilitate the attachment of the acoustic screen to the removable front wall, the latter comprises, according to a feature of the invention, at its face facing the engine compartment, fixing studs of the acoustic screen, by example by pegging. According to another characteristic of the invention to facilitate the assembly and disassembly of the front wall by limiting the number of elements which the operator must handle, the seal is secured to the removable front wall. . It should be noted that according to the invention, the sealing element can be made in any appropriate manner and for example constituted by a lip seal made of a polymer material or by a foam seal. The invention also relates to a motor vehicle comprising an awning box, according to the invention, interposed between the engine compartment and the passenger compartment of the vehicle. Of course, the different features of the invention can be combined with each other in different combinations, insofar as they are not incompatible or exclusive of each other. Moreover, various other features of the invention emerge from the following description made with reference to the drawings which show non-limiting embodiments of the object of the invention.

Figure 1 is a schematic section of a front region of a motor vehicle at the interface between the engine compartment and the passenger compartment, showing more particularly an awning box according to the invention. Figure 2 is a partial perspective of a front wall constituting the awning box as shown in Figure 1.

Figure 3 is a section similar to Figure 1, showing another embodiment of an awning box according to the invention.

FIG. 4 is an exploded perspective of fastening means implemented by the canopy casing illustrated in FIG. 3. FIG. 5 is a section similar to FIG. 1, showing still another embodiment of a casing of FIG. awning according to the invention.

Figure 6 is a partial perspective of the front wall of the canopy box shown in Figure 5, showing attachment means integrated with the front wall. As is apparent from Figure 1, an awning box, according to the invention and designated by the reference 1, is at the interface between the engine compartment C and the passenger compartment A of a motor vehicle. The awning box 1 is designed to allow the admission of ventilation air from the passenger compartment and a recovery of rainwater dripping on the windshield 2, when the vehicle is stationary or on the hood 3, when the motor vehicle rolls. For this purpose, the awning box 1 is delimited on the top by a grid 4 which allows air and water to pass while preventing the passage of bulky objects, such as tree leaves, or leaflets likely to close the box or the ventilation circuit 5 of the passenger compartment 1. The grid 4 extends between the windshield 2 and a front wall 6 delimiting the box 1. More specifically, the awning grid 4 is linked seals so that the rear part of the grid 4 is connected to a seal 5 'mounted integral with the lower edge of the windshield, while the front part is connected to a seal mounted on the front parai 6 of the box object of the invention.

Insofar as it ensures a maintenance of the grid 4, the front wall 6 is also called awning support. The front wall is fixed to the lateral structure, not shown, of the vehicle contributing to delimit the engine compartment C and a lower wall 7 said collector, which contributes to delimit the box 1 and which is also attached to the vehicle structure . According to the illustrated embodiment, the collecting wall 7 is made of sheet metal, while the front wall 6 is made of plastic material, such as, for example, polypropylene filled with long fibers known under the name PP GF30. In order to allow rapid access to the interior of the casing 1 to ensure, for example, the maintenance and repair of devices located inside the casing 1, such as means 10 for driving the wipers, the wall before 6 is removable. The awning box then uses removable fixing means 15 of the front wall 6 on the collecting wall 7. Moreover, insofar as geometric distortions are likely to exist at the interface between the removable front wall 6 and the collector wall 7, the invention provides for implementing a sealing element 16 interposed between the front wall 6 and the collector wall 7. Preferably and in order to facilitate the assembly and disassembly operations of the housing, the sealing member 16 will be integral with the front wall. The sealing element 16 may then be constituted for example by a foam seal bonded to the front wall 6 or by a lip seal made of elastomer, attached to the front wall 6 and fixed for example by a flange of the joint engaged in a groove in the front wall 6. Of course, any other mode of connection between the sealing member 16 and the removable front wall 6 could be considered. According to an essential characteristic of the invention and in order to guarantee the effectiveness of the element 16, both as regards its watertightness, and its ability to hinder the propagation of motor noise and bearings from the engine compartment to the passenger compartment, the fastening means 15 are adapted to ensure compression of the sealing element 16. More particularly preferably, the fastening means 15 are designed to constrain the sealing element 16 so that it has, when the attachment of the removable wall is completed, a height between 65% and 85% of its height at rest, or a height between 70% and 80% of its height at rest. Indeed, the inventors have demonstrated the fact that such a level of compression makes it possible to ensure optimal damping of the noise while maintaining an efficiency with regard to watertightness and have been able to demonstrate that greater compression of the sealing element leads to a deterioration of its noise attenuation performance, as well as an increase in rigidity, which promotes the propagation of noise as well as the deformation of the collecting wall 7. According to FIG. the invention, the fixing means 15 of the removable wall 6 on the collector wall 7 may be made in any suitable manner to the extent that they allow removal of the removable wall 6. According to the illustrated example, the fastening means 15 comprise, as shown in Figure 2, a series of articulated hooks 17, which are each integral with the removable wall 6. Each hook 17 is made of a sheet of metal folded so to have a generally U-shaped. One end of one of the branches of the hook 17 is then bent to surround an axis 18 forming an integral part of the removable wall 6. Thus, the hook 17 is secured to the front wall 6 while being movable in rotation relative to said front wall 6. The opposite end of the hook 17 is then bent so as to engage under an edge 19 of the collecting wall 7. Such an embodiment of the fastening means allows a particularly rapid mounting of the removable wall without special tools, simply by exerting on the back of the hook a sufficient pressure to allow its locking end 20 to engage under the edge 19 of the collector wall 7. Moreover, the character secured to the hooks 17 with the removable wall 6 avoids them any risk of disengage, during handling, the removable front wall 6. To further reduce in the passenger compartment From the engine compartment C, the invention provides for associating with the removable wall an acoustic screen 20 which is interposed between at least a portion of the removable front wall 6 and the engine compartment C. The screen 20 will then be preferably fixed by any appropriate means, such as for example by pegging on fixing studs 21 arranged at the face of the removable wall facing the engine compartment C. The acoustic screen 20 is for example constituted a hydrophobic topcoat and / or oleophobic and a heavy mass layer based on fibrous material, assembled and formed together by a thermoforming process.

According to a first embodiment, the fibrous material whose overall surface area is 3 kg / m 2, is composed of 90% glass wool and 10% phenolic resin. The topcoat is then made from PES fibers with traces of PP or PE.

According to another embodiment, the fibrous material whose overall basis weight is between 2.3 and 2.6 kg / m 2 is made from a felt comprising approximately 47% of PP, approximately 50% of PET and approximately 3% PUR-E. The topcoat comprises for example 65% of PET and 35% of a mixture based on PE and viscose.

As has been said above, the various shapes can be envisaged for the fixing means 15. Thus, FIGS. 3 and 4 illustrate another embodiment of the fastening means 15, according to which each fastening means comprises a metal clip 22 in U comprising, as shown in Figure 4, two upper branches 23 and lower 24 connected by a web 25. The upper branch 23 of the clip carries a fixing pin 26 intended to engage in a housing 27 arranged in the removable wall 6. The lower branch 24 carries, meanwhile, a hinge pin 28 on which is adapted a locking lever 29 rotatable in a clamping position, illustrated in Figure 4, and a loose position not shown . The lever 29 comprises, at an end 30 of adaptation on the axis 28, a cam configuration 31 adapted to ensure a rapprochement of the front wall 6 and the collector wall 7 so as to compress the element d sealing 16 when the lever 19 is in the clamping position. In order to maintain the lever 29 in this clamping position, the lever carries a locking hook 32 intended to engage, in the clamping position, on a locking pin 33 carried by the web 25 of the The lower leg 24 also carries a rear axle (not referenced) extending parallel to the axis 28, which forms a stop to the angular displacement of the lever 29 in the open position. The lever 29 thus remains accessible to the operator after positioning the removable wall 6 and clamping the latter on the collecting wall 7 by means of the lever 29.

Figures 5 and 6 illustrate yet another embodiment of the fastening means. According to this example, the fixing means 15 comprise a series of lugs 35 which are each carried by an elastically deformable arm 36 rigidly connected to the removable wall. Such an embodiment makes it possible to obtain fastening means directly during the molding or injection of the removable wall 6, which substantially reduces manufacturing costs. The lugs 35 are then intended to engage under the edge 19 of the collecting wall 7. Of course various other modifications can be made to the canopy of the invention according to the claims.

Claims (11)

Motor vehicle awning box placed between an engine compartment (C) and a passenger compartment (A) delimited at the front by a lower support beam of a windshield, the awning box being delimited by at least one - a lower wall (7) said manifold attached to the lower rail, - a removable front wall (6) located under the hood (3), interposed between the cover (3) closing the engine compartment (C) and the wall collector (7), and - an awning grid (5) extending between the front wall (6) and the windshield, characterized in that it comprises: at least one sealing element (16) interposed between the collecting wall (7) and the removable front wall (6), and - detachably fastening means (15) of the removable front wall (6) on the collecting wall (7) adapted to provide compression of the sealing element (16). Awning casing according to claim 1, characterized in that the fixing means (15) are adapted to compress the sealing element (16) so that it has a compression height of 65% and 85% of its height at rest. 3. Awning casing according to claim 1 or 2, characterized in that the fixing means (15) are integral with the removable front wall (6) and comprise a series of lugs (36) which are each carried by a resiliently deformable arm (35) rigidly connected to the removable front wall (6) and which are each adapted to engage under a locking edge (19) provided by the collector wall (7). 4. Canopy casing according to claim 1 or 2, characterized in that the fastening means (15) are integral with the removable front wall and comprise a series of articulated hooks (17) which are each movable relative to the wall removable front and which are each intended to engage under a locking edge (19) offered by the collector wall (7). Canopy casing according to claim 1 or 2, characterized in that the fixing means (15) comprise a series of U-shaped clips (22), each of which has two branches (23, 24) connected by a web ( 25), an upper branch (23) having opposite to the core (25) an end (26) intended to engage in a housing (27) provided by the removable wall, while the other leg base (24) is intended to extend under a locking flange (17) provided by the collecting wall (7), this lower branch (24) bearing an axis (28) intended to receive a movable locking lever (29). between a clamping position and a loosened position, the lever (29) having, at its adaptation end on the axis (28) of the clip (22), a cam configuration (32) adapted to ensure approximation of the removable front wall (6) and the collecting wall (7) so as to compress the sealing element (15) when that the lever (29) is in the clamping position. 6. Awning box according to one of claims 5, characterized in that it comprises an acoustic screen (20) which is interposed between at least a portion of the removable front wall (6) and the engine compartment (C). ) and which is secured to the removable front wall (6). 7. Awning box according to claim 6, characterized in that the removable front wall (6) comprises at its face facing the engine compartment studs (21) for fixing the acoustic screen (20). Awning casing according to Claim 6 or 7, characterized in that the acoustic screen (20) comprises a hydrophobic and / or oleophobic topcoat and a heavy-mass layer based on fibrous material, assembled and formed together by a thermoforming process. 9. Awning box according to one of claims 1 to 8, characterized in that the removable front wall (6) is made of plastic. 10. awning box according to one of claims 1 to 9, characterized in that the seal (16) is integral with the removable front wall (6). 11. Motor vehicle comprising an awning box (1) according to one of claims 1 to 10 interposed between the engine compartment (C) and the passenger compartment of the vehicle (A).