FR3038352A1 - ASSEMBLY FOR DOOR PANEL AND ASSOCIATED PANEL - Google Patents

Abstract

The present invention relates to an assembly (10) for producing an interior door panel of a motor vehicle, comprising a support element (14) and a covering element (16), which can be assembled one to the other. other in one direction (Z). The carrier element and the covering element respectively comprise a first (30) and a second (40) assembly surface, substantially perpendicular to the direction (Z). The second surface (40) is covered with a film (42) of a less hard material than the materials of the first and second surfaces. The first surface (30) has a plurality of linear reliefs (44) disposed substantially perpendicular to the direction (Z). Under the effect of a pressure exerted in the direction (Z), the reliefs come into contact with the second surface while passing through the film (42), so as to block in translation the first and second surfaces relative to each other. the other.

Description

Door panel and associated panel assembly

The present invention relates to an assembly for producing an appearance panel, in particular for forming an interior door panel of a motor vehicle.

More specifically, the invention relates to an assembly comprising: a carrier element adapted to be fixed to a door structure, and a covering element adapted to be assembled to the carrier element, in a first direction, the carrier element and the cladding element respectively comprising a first and a second assembly means, said first and second assembly means respectively comprising a first and a second surface substantially perpendicular to the first direction, said first and second surfaces being configured so that to come into contact during assembly of the carrier member and the cladding member, the first and second surfaces being respectively formed of first and second materials.

For reasons of weight reduction or ecological impact, it is advantageous to make vehicle components out of materials of natural origin. In particular, certain composite materials based on natural fibers in a polymer matrix are increasingly used, in particular to produce a covering element structure panels. For decorative purposes, such a covering element structure is commonly assembled to a covering, or skin. However, the natural fiber-based materials do not lend themselves to overmolding because the fibers can be flush with the surface of the structure. It is therefore preferable to make said assembly by heat-sealing: glue is sprayed onto the structure, which is then placed in contact with the skin in a heating mold.

Due to the constraints of the manufacturing process, it happens that part of the cladding element in contact with the carrier element is covered with a film of glue. Such a film creates a flexible interface between the two elements. It has been found that, during the movements of the vehicle comprising such a door panel, this interface plays in shear and generates noise pollution by friction between the carrier element and the trim element.

The object of the present invention is to provide a door panel assembly which does not have this problem of noise nuisance, without increasing the complexity and production cost of this type of panel. For this purpose, the subject of the invention is an assembly of the aforementioned type, in which the second surface is covered with a film of a third material, a hardness of said third material being lower than the hardnesses of said first and second materials; and the first surface comprises a plurality of linear reliefs arranged in a second direction substantially perpendicular to the first direction, said reliefs being able, under the effect of a pressure exerted in the first direction, to come into contact with the second surface; passing through the film of the third material, so as to lock in translation the first and second surfaces relative to each other in a third direction substantially perpendicular to the first and second directions.

According to other advantageous aspects of the invention, the assembly comprises one or more of the following characteristics, taken individually or according to all the possible technical combinations: the second surface comprises a plurality of linear grooves arranged substantially in the second direction said grooves being configured so as to fit at least partially on reliefs of the first surface when said first and second surfaces come into contact; - The reliefs of the first surface are able, under the effect of a pressure exerted in the first direction, to deform at least partially the second surface and to be inserted into the second material; one of the first and second means consists of a plurality of ribs, the other of the first and second means consisting of a plurality of grooves, said ribs and grooves being arranged in the third direction; the second material is a composite comprising fibers of natural origin in a polymer matrix; - The dressing element comprises a skin substantially disposed opposite the second surface in the first direction, the third material being an adhesive assembling said skin to the second material. The invention further relates to a method of producing an aspect panel from an assembly as described above, the method comprising the following steps: assembling the first and second assembly means; then applying a pressure in the first direction, so that the reliefs of the first surface come into contact with the second surface through the film of the third material; then at least partial attachment of the first and second assembly means, preferably by ultrasonic welding.

Advantageously, during the application of the pressure in the first direction, the grooves of the second surface fit at least partially on the reliefs of the first surface.

Advantageously, during the application of the pressure in the first direction, the reliefs of the first surface deform at least partially the second surface and fit into the second material. The invention further relates to an aspect panel, in particular for forming an interior door panel of a motor vehicle, which may be derived from a method as described above. The invention further relates to a motor vehicle comprising an inner door panel formed of such an aspect panel. The invention furthermore relates to a method for manufacturing a mold for producing a carrier element of an assembly as described above, said method comprising the following steps: providing a mold comprising a surface molding substantially smooth and substantially complementary to the first surface of the carrier member; then formation of shapes complementary to the reliefs of said first surface by chemical graining of said substantially smooth molding surface. The invention will be better understood on reading the description which follows, given solely by way of nonlimiting example and with reference to the drawings, in which: FIG. 1 is a partial schematic view, in longitudinal section, of an aspect panel assembly according to one embodiment of the invention; FIG. 2 is a partial schematic view, in cross section, of a panel formed from the assembly of FIG. 1; and FIG. 3 is a detail view, in longitudinal section, of the panel of FIG. 2.

Figure 1 shows an assembly 10 for producing an aspect panel 12, said panel being shown in Figures 2 and 3. The panel 12 is intended to form an interior door panel of a motor vehicle. The assembly 10 comprises a carrier element, or carrier 14, and a covering element, or strip 16. The carrier 14 and the strip 16 are able to be assembled to one another in a main assembly direction .

We consider an orthonormal basis (X, Y, Z), the principal assembly direction being parallel to Z.

A first face 18 of the carrier 14 is adapted to be fixed to a motor vehicle door structure, in particular by means of a set of staples in direct contact with the sheet metal of the structure of the door. A second face 20 of the carrier 14, opposite Z to the first face 18, is adapted to be assembled to the strip 16.

The second face 20 comprises at least one cavity 22 according to Z. A bottom 24 of said cavity has an elongated shape, substantially arranged along X. The bottom 24 has a central slot 26 and two lateral grooves 28 arranged on either side of the slot 26. The slot 26 and the grooves 28 extend along X. Near the slot 26, the first face 18 has a fastening surface 29 substantially disposed in a plane (X, Y). Bottoms of the lateral grooves 28 form a first assembly surface 30, substantially disposed in one or more planes (X, Y).

The attachment surfaces 29 and assembly 30, and possibly all or part of the rest of the carrier 14, are preferably made of a plastic material suitable for injection molding. The material is for example of the polypropylene type mixed with a chalk or talc type filler.

The strip 16 comprises a skin 32, for example made of polyvinyl chloride (PVC) polymer material. The skin 32 is substantially perpendicular to Z. A first face of the skin 32 is intended to be oriented towards the interior of the motor vehicle for decoration purposes.

The strip 16 further comprises a support 34, said support being secured to a second face of the skin 32, opposite the first face.

The support 34 is preferably made of a composite material suitable for injection molding and comprising fibers of natural origins in a polymer matrix. More preferably, the fibers of natural origin comprise hemp fibers and the polymer matrix comprises polypropylene (PP), with in particular a weight ratio of about 80% of polymer to 20% of fibers. A suitable material is in particular marketed under the name NAFILean®. This type of material allows a weight gain of 25% compared to the traditional material due to the low density of hemp.

On a face 35 opposite the skin 32 along Z, the support 34 has projecting ribs 36, 38 extending along X. More specifically, the ribs 36, 38 comprise at least one group formed by an insertion rib 36 flanked on both sides by two supporting ribs 38.

As illustrated in FIG. 2, the or each group formed of an insertion rib 36 and of two bearing ribs 38 is able to take place in the or one of the cavities 22 of the second face 20 of the wearer 14. during the assembly of said carrier 14 with the strip 16.

The insertion rib 36 is adapted to take place in the central slot 26 of the bottom 24 of the cavity 22. In particular, a peak 39 of the insertion rib 36 is configured so as to form a projection on the surface side fastener 29 when the carrier 14 and the strip 16 are assembled.

The support ribs 38 are configured to be in contact with the grooves 28 of the bottom 24 of the cavity 22 when the carrier 14 and the strip 16 are assembled. In particular, ridges of the supporting ribs 38 form a second joining surface 40, substantially disposed in one or more planes (X, Y). The second assembly surface 40 is intended to be in contact with the first assembly surface 30 of the lateral grooves 28 during assembly of the carrier 14 and the strip 16.

Preferably, a tolerance of a few tenths of millimeters along X and Y is provided for the assembly of the carrier 14 and the strip 16. In particular, a thickness along Y of the insertion rib 36 is slightly less than a thickness according to Y of the central slot 26. Similarly, a width along Y of the second assembly surface 40 at the crest of a support rib 38 is slightly smaller than a width along Y of the first assembly surface. 30 at the bottom of a lateral groove 28.

Furthermore, the support 34, and in particular the second joining surface 40, are partially or completely covered with a film 42 of an adhesive material, shown in the detail view of FIG. 3. Preferably, the film 42 of adhesive material secures the support 34 and the skin 32.

Because of its mode of deposition on the support 34 of the strip 16, the film 42 of adhesive material is present on a large surface of the strip 16 including its assembly face 40 with the carrier 18. In fact, given the relatively complex shape of the strip, it is difficult to deposit the adhesive material other than by spraying. This deposition mode does not allow optimal control, so that the adhesive material is not deposited solely on the part of the support 34 intended to receive the skin 32.

The film 42 of adhesive material has a lower hardness than the materials constituting the carrier 14 and the support 34. In particular, the film 42 has a higher elasticity and ductility than the materials constituting the carrier 14 and the support 34. elsewhere, the film 42 is likely to soften with an increase in temperature.

When the film 42 is interposed between the first 30 and second 40 assembly surfaces, said film is in particular capable of shearing along X during a movement of the motor vehicle comprising the panel 12. The first 30 and second 40 surfaces are thus likely to move relative to each other, causing a noise perceptible by the users of the vehicle.

In order to remedy this inconvenience, the first assembly surface 30 comprises a plurality of linear reliefs 44, arranged substantially along Y.

Preferably, all the linear reliefs 44 have substantially the same thickness 46 according to Z.

Because of the respective hardnesses of the materials, the reliefs 44 are able, under the effect of a pressure exerted along Z of the strip 16 towards the carrier 14, to pass through the film 42 until it comes into contact with the second surface of assembly 40.

In particular, said bringing into contact between the reliefs 44 of the first assembly surface 30 and the second assembly surface 40 is able to block in translation the first 30 and second 40 surfaces with respect to one another according to direction X, to remove the noise mentioned above.

According to a first variant, the second assembly surface 40 comprises a plurality of linear grooves 48, arranged substantially along Y. Preferably, the grooves 48 have dimensions close to those of the reliefs 44 of the first assembly surface 30. In particular, the grooves 48 preferably have a depth 50 along Z substantially equal to the thickness 46 of the reliefs 44.

The grooves 48 are configured so that, when the first 30 and second 40 joining surfaces are brought into contact, at least some of the grooves 48 fit at least partially onto some of the reliefs 44. As represented in FIG. , some of the reliefs 44 pass through the film 42 of adhesive material to come into contact with a wall of some of the grooves 48. The first 30 and second 40 surfaces are thus locked in translation relative to one another according to X.

Preferably, respective distances along X between the reliefs 44 and between the grooves 48, and an assembly tolerance along X between the carrier 14 and the strip 16, are provided so that several reliefs 44 are received in grooves 48 during said assembly.

According to a second variant, under the effect of the pressure exerted according to Z, the reliefs 44 are capable of stamping the second joining surface 40, so as to create impressions 52 in the material of the support 34. The interlocking of the reliefs 44 in the fingerprints 52 translational locks the first 30 and second 40 surfaces relative to each other in the direction X.

As illustrated in FIG. 3, the first and second variants described above are advantageously combined in one and the same embodiment.

According to a third variant, the contact between the reliefs 44 and the second joining surface 40 is associated with a coefficient of friction sufficient to limit or prevent a displacement of the first 30 and second 40 surfaces with respect to each other, especially in direction X.

A method of making assembly 10 and panel 12 will now be described.

Firstly, injection molds are provided in order to produce the carrier 14 and the support 34 of the strip 16. Said injection molds are configured for producing substantially complementary shapes for the second face 20 of the carrier 14 and the In particular, said injection molds are configured for producing at least one cavity 22 on the face 20 of the carrier 14 and at least one group of ribs 36, 38 on the face 35 of the carrier. support 34.

A mold for the carrier 14 is preferably made from an existing mold, making striations corresponding to the reliefs 44 by chemical graining on a smooth surface corresponding to the first assembly surface 30. The chemical graining makes it possible to obtain striations of homogeneous depths in order to obtain reliefs 44 having substantially the same thickness 46.

The chemical graining is in particular carried out by depositing an acidic composition of controlled viscosity on a mask whose slots correspond to the desired grooves for the relief 44. The depth of the grooves is determined by the time during which the acid composition is allowed to act.

The carrier 14 and the support 34 of the strip 16 are then produced, independently of one another, by injection molding.

Glue is then sprayed onto the support 34, in particular on both sides of said support 34, forming the film 42. Generally, the adhesive used is an aqueous polyurethane dispersion. The support 34 and the skin 32 are then assembled by heat-sealing in a heating mold, forming the strip 16.

The carrier 14 and the strip 16 are then assembled by approximation in the direction Z, so that the or each group of ribs 36, 38 takes place in a cavity 22, as shown in Figure 2. The insertion rib 36 is inserted in the central slot 26 of the bottom 24. The ridges of the supporting ribs 38 come into contact with the bottoms of the lateral grooves 28. At this stage, the film 42 of adhesive which covers the support 34 is interposed between the first 30 and the second 40 joining surfaces.

Pressure is then exerted along Z in order to bring the carrier 14 closer to the strip 16. The reliefs 44 of the first assembly surface 30 deform and pass through the film 42 to make contact with the second joining surface 40.

A portion of the reliefs 44 is notably received in grooves 48 of the second joining surface 40. Another portion of the reliefs 44 penetrates into said second surface 40, creating impressions 52.

The carrier 14 and the strip 16 are then fixed by ultrasonic welding of the insertion ribs 36. Sonotrodes are positioned on the ridges 39 of the ribs 36, so as to locally apply ultrasound. Ultrasound causes friction of small amplitude but high frequency, which generates a local melting of the polymer forming the peaks 39. A bead is thus formed in contact with the fixing surface 29, near the slots 26. The insertion ribs 36 are welded to the corresponding slots 26, solidarisant the carrier 14 and the strip 16. The panel 12 is thus obtained.

The bearing ribs 38, which are not welded to the corresponding lateral grooves 28, are locked in translation along X relative to said grooves, by the insertion of the reliefs 44 in the grooves 48 and / or in the indentations 52, or because of a significant coefficient of friction between the first 30 and second 40 joining surfaces.

When moving a vehicle comprising a panel 12 as an inner door panel, said panel 12 is therefore unlikely to generate noise nuisance by friction between the support ribs 38 and the lateral grooves 28.

It should be noted that if the invention just described is particularly suitable for the use of bands made from composites based on natural fibers, it may relate to any type of headband whenever the presence of a glue film at the interface between the band and its wearer will likely cause noise.

Claims (12)

1, -Set (10) for producing an aspect panel (12), in particular for forming an interior panel of a motor vehicle door, said assembly comprising: - a carrier element (14) adapted to be fixed to a door structure, and - a covering element (16) adapted to be assembled to the carrier element, in a first direction (Z), the carrier element and the covering element respectively comprising a first (22) , 28) and a second (36, 38) assembly means, said first and second assembly means respectively comprising a first (30) and a second (40) surfaces substantially perpendicular to the first direction, said first and second surfaces; being configured to come into contact during assembly of the carrier member and the cladding member, the first and second surfaces being respectively formed of first and second materials, the panel being characterized in that: - the second surface (40) is covered with a film (42) of a third material, a hardness of said third material being less than hardnesses of said first and second materials; and - the first surface (30) comprises a plurality of linear reliefs (44) arranged in a second direction (Y) substantially perpendicular to the first direction, said reliefs being capable under the effect of a pressure exerted in the first direction , to come into contact with the second surface by passing through the film (42) of the third material, so as to block in translation the first and second surfaces relative to one another in a third direction (X) substantially perpendicular to the first and second directions. 2, - assembly according to claim 1, wherein the second surface (40) comprises a plurality of linear grooves (48) disposed substantially in the second direction (Y), said grooves being configured so as to fit at least partially on reliefs (44) of the first surface (30) upon contacting said first and second surfaces. 3, - assembly according to claim 1 or claim 2, wherein the reliefs (44) of the first surface are able, under the effect of a pressure exerted in the first direction (Z), to deform at least partially ( 52) the second surface and to insert into the second material. 4. - An assembly according to one of the preceding claims, wherein one of the first and second means consists of a plurality of ribs (38), the other of the first and second means being constituted by a plurality of grooves. (28), said ribs and grooves being arranged in the third direction (X). 5. - assembly according to one of the preceding claims, wherein the second material is a composite comprising fibers of natural origins in a polymer matrix. 6. - assembly according to one of the preceding claims, wherein the cladding element (16) comprises a skin (32) substantially disposed opposite the second surface (40) in the first direction, the third material being an adhesive assembling said skin to the second material. 7. - Process for producing an aspect panel (12) from an assembly (10) according to one of the preceding claims, comprising the following steps: - assembly of the first (22) and second (36, 38) assembly means; then - applying a pressure in the first direction (Z), so that the reliefs (44) of the first surface (30) come into contact with the second surface (40) passing through the film (42) of the third material ; then - at least partially solidarization of the first and second assembly means, preferably by ultrasonic welding. 8. - Method according to claim 7 taken in combination with claim 2, wherein, during the application of the pressure in the first direction, the grooves (48) of the second surface at least partially nest on reliefs (44) of the first surface. 9. - The method of claim 7 taken in combination with claim 3, wherein, during the application of the pressure in the first direction, the reliefs of the first surface at least partially deform (52) the second surface and s insert into the second material. 10. - Aspect panel (12), in particular for forming an interior door panel of a motor vehicle, may be derived from a method according to one of claims 7 to 9. 11. - Motor vehicle comprising an inner door panel formed of an aspect panel (12) according to claim 10. 12. - A method of manufacturing a mold for producing a carrier member (14) of an assembly (10) according to one of claims 1 to 6, said method comprising the following steps: - providing a mold comprising a molding surface substantially smooth and substantially complementary to the first surface (30) of the carrier member; then - formation of shapes complementary to the reliefs (44) of said first surface by chemical graining of said substantially smooth molding surface.