FR3055598A1 - ACOUSTIC PROTECTION DISPLAY FOR MOTOR VEHICLE ENGINE - Google Patents

Abstract

The invention relates to a screen (1) comprising: a shell (3) of molded appearance based on polyurethane foam with a density of between 0.38 and 0.42, the location face (4) of said shell being devoid of coating so as to form the appearance side of said screen; a molded acoustic absorption underlayer (5) based on polyurethane foam having a density of between 0.12 and 0.28, said underlayer overmolding the backside face (6) of said shell by penetrating it on a fraction of its thickness so as to form an over-densified crust (7) forming a sealing barrier between said underlayer and said shell, so that said screen is further acoustically insulating.

Description

© Publication no .: 3,055,598 (to be used only for reproduction orders)

©) National registration number: 16 58183 ® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY

COURBEVOIE © Int Cl ⁸ : B 60 R 13/08 (2017.01), G 10 K 11/168, B 29 C 44/58

A1 PATENT APPLICATION

©) Date of filing: 02.09.16. ©) Applicant (s): CERA APS Société par actions simpli- ©) Priority: trusted - FR. @ Inventor (s): RIBES STEPHANE, DREZET DAVID, CAPRON CHRISTOPHE and MARTINS CARLOS. (43) Date of public availability of the request: 09.03.18 Bulletin 18/10. ©) List of documents cited in the report preliminary research: Refer to end of present booklet (© References to other national documents ©) Holder (s): CERA APS Société par actions simpli- related: trusted. ©) Extension request (s): ©) Agent (s): STRATO-IP Limited liability company.

(04) SOUND PROTECTION SCREEN FOR MOTOR VEHICLE ENGINE.

FR 3 055 598 - A1 _ The invention relates to a screen (1) comprising: a shell (3) of molded appearance based on polyurethane foam with a density between 0.38 and 0.42, the front side (4) of said shell being devoid of coating so as to form an appearance face of said screen; a molded sound absorption sublayer (5) based on polyurethane foam with a density between 0.12 and 0.28, said sublayer overmolding the underside (6) of said shell by penetrating it over a fraction of its thickness so as to form an over-densified crust (7) forming a sealing barrier between said underlay and said shell, so that said screen is also acoustically insulating.

5

The invention relates to an acoustic protection screen for a motor vehicle engine and to a method for producing such a screen.

It is known to produce an acoustic protection screen for a motor vehicle engine, said screen comprising a body based on molded polyurethane foam with a density between 0.38 and 0.42, the front face of said body being devoid of coating so as to form an aspect face of said screen.

The appearance face can in particular be provided with a graining resulting from molding.

The possibility of freeing oneself from a coating results from the high density of the foam which, as a result, has few bubbles of such a nature as to harm the surface appearance of the body.

However, foams of such density have poor sound absorption properties.

To remedy these drawbacks, it could be proposed that the body be made from lesser density foam, which would make it possible to gain in absorption but, on the other hand, to have weakened insulation properties.

In addition, a lower density foam has the disadvantage of being able to do without being provided with a coating, since the increased presence of bubbles degrades the surface appearance of the body, which induces an additional cost.

The object of the invention is to overcome these drawbacks by proposing a screen which has both an advantageous appearance side, while not being provided with a coating, and good sound absorption and insulation properties.

To this end, and according to a first aspect, the invention provides an acoustic protection screen for a motor vehicle engine, said screen comprising a body based on polyurethane foam, said body comprising:

• a shell of molded appearance based on polyurethane foam with a density between 0.38 and 0.42, the right side of said shell being devoid of coating so as to form the aspect of said screen, • a molded sound absorption underlay based on polyurethane foam with a density between 0.12 and 0.28, said underlay overmolding the underside of said shell by penetrating it over a fraction of its thickness so forming an over-densified crust forming a sealing barrier between said underlay and said shell, so that said screen is also acoustically insulating.

With the proposed arrangement, one obtains for the screen an aspect identical to that known on screens of the prior art, the body of which is based on high density foam.

In addition, the presence of the lower density foam-based underlay improves its absorption properties, the presence of the waterproof crust further conferring insulation properties on the screen.

According to a second aspect, the invention proposes a method for producing such a screen.

Other features and advantages of the invention will appear in the following description, made with reference to the attached figure which is a schematic sectional view of a screen according to an embodiment.

Referring to the figure, a screen 1 for acoustic protection for a motor vehicle engine is described, said screen comprising a body 2 based on polyurethane foam, said body comprising:

A shell 3 of molded appearance based on polyurethane foam with a density of between 0.38 and 0.42, the front face 4 of said shell being devoid of coating so as to form the appearance face of said screen, • an acoustic absorption sublayer 5 molded from polyurethane foam with a density between 0.12 and 0.28, said sublayer overmolding the reverse side 6 of said shell by penetrating it over a fraction of its thickness so as to form an over-densified crust 7 forming a sealing barrier between said underlay and said shell, so that said screen is also acoustically insulating.

According to the embodiment shown, the sub-layer 5 extends substantially over the entire reverse side 6 of the shell 3.

According to one embodiment, the front face 4 of the shell 3 is provided with a graining resulting from molding

According to one embodiment, the crust 7 has a thickness of less than 1 mm.

According to the embodiment shown, the screen 1 also comprises at least one element 8 for fixing said screen to the vehicle engine, said element being molded by the shell 3.

The element 8 shown is in particular made of molded plastic material and is arranged to receive in interlocking a stud from the engine of the vehicle.

The fact that the fastening element 8 is overmolded by the foam of the shell 3, having the highest density, makes it possible to anchor it robustly in the screen 1, and to avoid its tearing during operations of mounting / dismounting of said screen.

Finally, a method for producing such a screen 1 is described, said method comprising the following steps:

• make a shell 3 of molded appearance based on polyurethane foam with a density between 0.38 and 0.42, • transfer said shell into a mold with the geometry of the body 2 to be obtained, • inject on the face of upside down 6 of said shell a precursor mixture of polyurethane foam with a density between 0.12 and 0.28, so as to produce an acoustic absorption sublayer 5 overmolding said reverse side, · release the body 2 obtained .

According to one embodiment, the production of the shell 3 in appearance incorporates an overmolding operation of at least one fixing element 8 by said shell.

Claims (7)

1. Screen (1) for acoustic protection for a motor vehicle engine, said screen comprising a body (2) based on polyurethane foam, said screen being characterized in that said body comprises: • a shell (3) of molded appearance based on polyurethane foam with a density between 0.38 and 0.42, the front face (4) of said shell being devoid of coating so as to form a face of appearance of said screen, • an acoustic absorption sub-layer (5) molded from polyurethane foam with a density of between 0.12 and 0.28, said under-layer overmolding the reverse side (6) of said shell in penetrating it over a fraction of its thickness so as to form an overdensified crust (7) forming a sealing barrier between said underlay and said shell, so that said screen is also acoustically insulating. 2. Screen according to claim 1, characterized in that the sub-layer (5) extends substantially over the entire reverse side (6) of the shell (3). 3. Screen according to one of claims 1 or 2, characterized in that the facing face (4) of the shell (3) is provided with a graining from molding 4. Screen according to any one of claims 1 to 3, characterized in that the crust (7) has a thickness less than 1 mm. 5. Screen according to any one of claims 1 to 4, characterized in that it further comprises at least one fixing element (8) of said screen integrally with the engine of the vehicle, said element being overmolded by the shell (3) . 6. A method of producing a screen (1) according to any one of claims 1 to 5, said method comprising the following steps: • make a shell (3) of molded appearance based on polyurethane foam with a density between 0.38 and 0.42, 5 · transfer said shell into a mold with the geometry of the body (2) to be obtained, • inject on the reverse side (6) of said shell a precursor mixture of polyurethane foam with a density between 0.12 and 0, 28, so as to produce an acoustic absorption sublayer (5) 10 overmolding said reverse side, • release the body (2) obtained. 7. Method according to claim 6, characterized in that the embodiment of the shell (3) in appearance incorporates an overmolding operation of at least one element 15 for fixing (8) by said shell. 1/1