FR3081368A1 - METHOD FOR MANUFACTURING A SET OF TWO ASSEMBLED PIECES AND RESULTANT ASSEMBLY - Google Patents

Abstract

The subject of the present invention is a method of manufacturing an assembly (1) of mutually assembled two pieces (2, 3), comprising a piece of packing (2) referenced on a support (4) and a composite part ( 3) structural and / or dressing consisting of the support (4), an intermediate layer (5) and a skin (6) forming the apparent surface of the composite part (3). Characterized in that it consists in providing a support (4) comprising, at the or each location corresponding to a milling location of a through hole (7) receiving an assembly element of the lining piece ( 2), a recess defining at least one axial shoulder (12) with the rear face (4 ') of the support (4) and in that the milling operation of the orifice or each through orifice (7) in the composite part (3) consists of digging to at least open into the recess, while preserving at least part of the shoulder (12) constituting the site of engagement of the corresponding connecting element.

Description

DESCRIPTION

The present invention relates to a method of manufacturing a set of assembled parts, comprising a trim or covering part referenced on a support, in particular for the passenger compartment of a motor vehicle, as well as a set of assembled parts obtained from such a manufacturing process, and a motor vehicle equipped with such a set of parts.

Certain assemblies of a trim piece on a support, in particular for the interior trim of motor vehicles, such as a dashboard, comprise a fastening of the trim on a front face of the support by clipping, giving a quick assembly with no apparent fastening system.

In particular, the support can be covered by a skin with a foam inserted below, in order to present a slightly flexible outer surface forming a luxurious covering and pleasant to the touch.

One type of fastening system known for such an assembly, presented in particular by document FR-A1-2 895 949, comprises a support such as a dashboard of a motor vehicle, covered by foam and a skin. A piece of trim (forming a headband, rod or decorative strip) comprises, at the rear T, rods each equipped with a hook, which penetrate into holes in the support and the skin.

Each drilling area of the support has on its rear face a particular shape protruding behind this face, which is milled with a tool coming from behind T to make a drilling of this support. The skin and the foam are then pierced with a punch coming from the front, to form a passage receiving the rear rod of the lining.

When each rod is recessed in its bore, the hook of the rod comes behind an edge located near the milled zone, to make a clipping keeping the piece of trim blind.

However, this process requires, in addition to milling from the back, an additional punching operation from the front in order to pierce the skin and the foam, which requires operating time and adds costs.

In addition, for this process, it is necessary to produce a particular projecting shape on the rear face of the support undergoing milling, which

-2 adds bulk which can in some cases be annoying. In addition, it will also be noted that on certain supports the rear side may be difficult to access for milling the particular shape.

In addition, the construction presented in this document requires a determined conformation of the visible face (presence of a groove or a hollow) and is only suitable for a certain type of inserts of very specific shapes.

Finally, the fitting of the trim piece is carried out parallel to the apparent surface in a recess of this surface.

Furthermore, assembly solutions are also known by clipping with hooking on the rear, in particular for trim pieces added to the surface, for example of the strip type or covering frame for a display screen, in which the fixing is obtained by interlocking substantially perpendicular to the support.

Figures IA to 1E schematically illustrate the main steps of an illustrative example of such a known method.

After manufacturing the foam dashboard (Figures IA and IB), comprising a rigid support, a skin and an intermediate layer of foam, a rotary cutter pierces then digs the panel to form a through hole cut in the three layers (Figures IC and 1D - for example: milling cutter with propeller on the left and turning with a rotation to the right to push the chips beyond the support). At each assembly site, a hook clip, formed on the rear of the trim piece, is then pushed into the hole and engages with the milled edge of the latter (Figure 1E). This assembly is, however, subject to significant dispersions in terms of dimensions and position making it difficult, even impossible, great assembly precision and repeatability with sufficient reliability.

Indeed, the dimensional dispersions of the different layers and those of the milling operation itself cumulate (Figure 1E).

In particular at the level of the support, on the back of which the assembly clip is attached, the anchoring site is constituted by an edge cut by the cutter, not specifically reinforced and whose precision in terms of shape and dimension is not optimal, and generally considered insufficient.

-3 The present invention aims in particular to solve these problems of the prior art.

To this end, it proposes a method of manufacturing a set of two mutually assembled parts, comprising a piece of trim referenced on a support, consisting in providing a composite structural part and / or covering composed, successively of its face rear towards its front face, of the support, of an intermediate layer, in particular of foam, and of a skin forming the apparent surface of the composite part, to produce at least one through hole in the composite part by drilling or milling from the front or visible surface, to provide a trim piece provided, on its rear face, with at least one protruding assembly element comprising an engagement means, for securing the trim piece with the composite piece by applying the rear face of the trim piece against the skin of the composite piece and simultaneous introduction of the element or of each assembly element into the orifice or a gold corresponding ifice passing through the composite part until it engages with the support, method characterized in that it consists in providing a support comprising, at the or each location corresponding to a location for drilling or milling a through hole, a recess or recess defining at least one shoulder or axial rim with the rear face of the support opposite to the intermediate layer and in that the drilling or milling operation of the orifice or of each orifice passing through the composite part consists in digging from the apparent surface of the composite part until at least opening into the recess or hollow, while preserving at least part of the shoulder or the rim constituting the site of engagement of the element corresponding assembly.

The invention will be better understood from the following description, which relates to preferred embodiments, given by way of nonlimiting examples, and explained with reference to the appended schematic drawings, in which:

FIGS. 2A to 21 illustrate, by partial views in lateral elevation and in section, the main stages in the manufacture of a set of parts assembled according to an embodiment of the method of the invention;

FIGS. 3A to 3H illustrate, with views of a type similar to those of FIGS. 2, an alternative embodiment of the method according to the invention, and FIGS. 4A to 4C are respectively a bottom view of a piece of trim according to the invention (in the form of a covering frame - FIG. 4A), a perspective view illustrating the mounting with assembly by fitting of the frame of FIG. 4A in a dashboard panel (FIG. 4B) and a view from below of the dashboard panel of FIG. 4B after assembly of the frame of FIG. 4A by interlocking with clipping.

The invention relates, as shown in Figures 2 and 3, a method of manufacturing an assembly 1 of two parts 2, 3 mutually assembled, comprising a trim part 2 referenced on a support 4.

This process essentially consists of:

to provide a composite structural and / or covering composite part 3 composed, successively from its rear face to its front face 3, of the support 4, of an intermediate layer 5, in particular of foam, and of a skin 6 forming the surface visible 3 'of the composite part 3, to produce at least one through hole 7 in the composite part 3 by drilling or milling from the front or visible surface 3', to provide a piece of trim 2 provided, on its rear face 2 ' , of at least one protruding assembly element 8 comprising a means 9 for engaging, to secure the trim piece 2 with the composite piece 3 by applying the rear face 2 'of the trim piece 2 against the skin 6 of the composite part 3 and by simultaneous introduction of the element or of each assembly element 8 into the orifice or a corresponding orifice passing through 7 of the composite part 3, until the or each means 9 comes into taken with support 4.

Each through orifice 7 can be obtained either by drilling by a single downward movement of a cutter 14 of suitable diameter, or by vertical downward drilling, then lateral digging by means of a cutter 14 of diameter smaller than that of the orifice through 7. In both cases, the machining of the composite part 3 is carried out from the visible face 3 'of this part.

-5 In accordance with the invention, the method consists in providing a support 4 comprising, at the or each location 10 corresponding to a location for drilling or milling a through orifice 7, a recess or a recess 11 defining at at least one shoulder or axial rim 12 (lateral on one side, or circumferential, partially or totally) with the rear face 4 ′ of the support 4 opposite the intermediate layer 5.

In addition, the drilling or milling operation of the orifice or of each through orifice 7 in the composite part 3 consists in digging from the apparent surface 3 ′ of the composite part 3 until at least opening into the recess or hollow 11, while preserving at least part of the shoulder or the rim 12 constituting the site of engagement of the corresponding assembly element 8.

Thanks to the invention, the engagement or engagement site 12 for the adapted means 9 of the assembly element 8, at each local assembly location, is formed during the manufacture of the support 4 and not during the digging of the through orifice 7, making it possible to achieve reliable repeatability in terms of shape and dimension. In addition, a site 12 in the form of a shoulder or rim, not directly stressed mechanically during digging, provides high rigidity and resistance to deformation.

Preferably, the digging of each through orifice 7 is carried out by milling and the part 13 of each through orifice 7 resulting from the milling operation has a cross section S greater than that S 'of the contiguous recess or recess 11.

Such an arrangement makes it possible to absorb the dispersions of the excavation at the level of the intermediate layer 5 and to avoid any interference with the assembly connection with the support 4 of the element 8.

Advantageously, the or each recess 11 of the support 4 has a side wall 11 'extending substantially perpendicularly from the rear face 4' of said support 4, and therefore also advantageously in the direction D of initial introduction of the milling tool 14 , and constitutes a blind hole with a bottom wall 11, molded or added. The digging operation of the corresponding through orifice 7 removes at least said bottom wall 11, thus leaving a shoulder 12 with a rim formed by a part 12 ′ at least of the axial contour (side wall 1Γ) of the recess 11.

-6Thus, in a single milling operation from the front, we cut both the skin 6, the foam layer 5 and the bottom 11 of the hollow 11 of the support 4 which, on the one hand, clears the drilling well by virtue of the wider cutting of the foam 5 and of the skin 6 and, on the other hand, produces on the support 4 a clear bore, surrounded by the shoulder 12 with the rim 12 ′ of the axial contour of the hollow 11, remaining after milling.

According to a characteristic of the invention, the method very favorably consists in providing a trim piece 2 with several elongated assembly elements 8 each comprising an indexing surface 8 'intended to come into abutment against the shoulder 12 (or the rim of the latter) of the through orifice 7 receiving the assembly element 8 considered and a means 9 for engagement intended to come into engagement by hooking or clipping on the rear face 4 ′ of the support 4 in the state final assembly of the lining part 2 with the composite part 3.

The part 2 preferably comprises several assembly elements 8 distributed over its rear face 2 ′, for example on the periphery thereof, the composite part 3 being provided with as many orifices 7.

After the milling operation, which does not dig up to the bitter side 4 'of the support 4 and therefore does not affect the shoulder 12, nor the internal flange 12' of the latter, the workpiece can easily be laid. gasket 2 on the front face 3 'of the composite part 3 by introducing the rod-shaped body of the element 8 inside the remaining part 12 of the axial contour 11' of the recess 11, which achieves precise referencing of the trim part 2 on the support 4 and the composite part 3. In addition, for a rod fitted with a hook 9, this hook can then be stapled on the rear face 4 ′ of the support 4, which ensures that it is held locked to said trim piece 2, comprising precise lateral and axial positioning given by the position of each element 8 in its associated orifice 7 and the engagement of the hook 9 coming to be fixed on the rear face 4 ′ of the support 4, at the level from shoulder 12.

In accordance with a characteristic of the invention, it can be provided that, during the movement of introducing an assembly element 8 into a through orifice 7 during the operation of securing the lining part 2 with the part composite 3 machined by milling, said assembly element 8 is elastically deformed by interference from the engagement means 9, for example a hook or notch with a slope, with the shoulder or rim portion 12 preserved.

-7 The assembly is thus carried out by elastic engagement automatically at the end of nesting.

As shown for example in figures 2D to 2F and figures 3D to 3G, the milling operation is carried out by a milling tool or cylindrical milling cutter 14 comprising a cut on its circular part and a cut on its end. In addition, the milling operation includes lowering said cutter 14, and lateral movements of this cutter 14 to dig the entire bottom 11 of the recess or recess 11 of the support 4, while preserving at least part of the side wall 11 ′ of said hollow 11, the rotation of the milling operation causing chip evacuation.

It can be noted that the milling operation carried out from the front does not impose significant precision in positioning the milling cutter 14, this milling being able both to protrude beyond the sides of the axial contour, and to descend behind the height of the bottom 11 of the recess 11. The functional part of the bore necessary for positioning and fixing the hook 9, comprising the rear face 4 'of the support 4 and the remaining part of the axial contour (side wall 11' and shoulder 12), close to this rear face 4 ′ is not affected by machining.

Advantageously, the bottom 11 is formed in one piece with the side wall 11 ′ of the recess 11 and therefore with the support 4.

However, in accordance with an alternative embodiment of the invention, shown in FIGS. 3A to 3H, it can be provided that, when the recess 11 in the support 4 is devoid of bottom, and is for example in the form of a nozzle or segment of open tube 11 ′, to perform, before the formation of the intermediate layer 5 of foam, a preliminary operation of fitting a cover 15, in the form of an adhesive film, on the open end of said end piece 11 'which is opposite the rear face 2', to form a bottom 11.

Favorably in terms of ease, flexibility, variety of shapes and production costs, the trim piece 2 and the support 4 are made by molding of thermoplastic material, preferably each in one piece. However, the trim piece can also comprise several elements, such as a support and a decoration part with for example a film, a textile, a skin or the like (with possibly a skin intermediate between the support and the decor surface).

The invention also relates, as shown in particular in FIGS. 21 and 4C, to a set 1 of two parts 2 and 3 mutually assembled, comprising, on the one hand, a trim piece 2 provided, on its rear face 12 ' , at least one protruding assembly element 8 and, on the other hand, a composite structural part 3 and / or covering constituted, successively from its rear face towards its front face, by a support 4, by a layer intermediate 5, advantageously molded, preferably made of foam, and by a skin 6 forming the apparent surface 3 ′ of said composite part 3. The assembly or joining connection between the two parts 2 and 3 above-mentioned consists of a cooperation of at least one connecting element 8 projecting with at least one corresponding through hole 7 of the composite part 3, the or each connecting element 8 extending through the corresponding through hole 7 and comprising a means 9 for engaging with the support 4 at the rear face 4 'of the latter.

This assembly 1 is characterized in that the through orifice 7 comprises a first part 13 hollowed out in the skin 6 and in the intermediate layer 5 and a second complementary part 12 formed by a shoulder or axial rim of the support 4, extending from the rear face 4 ′ of said support 4 in the intermediate layer 5 and in the direction of the skin 6, and in that the or each assembly element 8 is, on the one hand, in lateral support against the shoulder 12 to 1 'interior of the through hole 7 concerned and, on the other hand, engaged with the rear face 4' of the support 4 by means of a corresponding suitable means 9.

Preferably, each shoulder 12 has an at least partially circumferential contour, for example substantially circular or elliptical, and each assembly element 8 is positioned in the corresponding through orifice 7 by lateral support against a portion of wall 11 'projecting into the layer intermediate 5 from the substrate 4 and corresponding to the axial rim 12 'of said shoulder 12, all of said covering elements 8 cooperatively ensuring the fastening by snapping under tension and the indexed positioning of the trim piece 2 relative to the piece composite 3.

However, as a variant, the shoulder 12 can also have a square or rectangular shape and / or extend only over part of a side, over one side, or over several sides, but without being closed circumferentially.

-9Thus, the milling operation may leave only a portion 12 'circumferentially limited of the side wall 11' of the recess 11, against which abuts the corresponding assembly element 8, during its mounting with hooking on the rear face 4 'of the support 4.

Advantageously, each assembly element 8 has a rod-shaped body with means 9 for engaging by hooking, for example a hook, advantageously formed at or near the free end of said rod.

The assembly according to the invention is very favorably obtained by means of the method described above.

In the context of a preferred application of the invention, the composite part 3 is a dashboard of a motor vehicle, as shown in FIGS. 4A to AC by way of example.

These figures also illustrate that, when the through orifice 7 and the trim piece 2 are large, the orifice may comprise along its lateral edge numerous shoulders 12 extending over only part of one side and the trim part 2 then be provided with a plurality of assembly elements 8, ensuring together the wedging in position and the securing of said trim part 2 relative to the composite part 3 which receives it.

The invention also relates to a motor vehicle equipped with a set 1 of assembled parts comprising a dashboard 3 receiving at least one trim part 2, this set of parts being a set of parts 1 as described above.

Of course, the invention is not limited to the embodiments described and shown in the accompanying drawings. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without thereby departing from the scope of protection of the invention.

Claims (14)

1. Method for manufacturing a set (1) of two mutually assembled parts (2, 3), comprising a trim part (2) referenced on a support (4), consisting in providing a composite part (3) structural and / or covering composed, successively from its rear face towards its front face (3), of the support (4), of an intermediate layer (5), in particular of foam, and of a skin (6) forming the apparent surface (3 ') of the composite part (3), to produce at least one through hole (7) in the composite part (3) by drilling or milling from the front or visible surface (3'), to provide a trim piece (2) provided, on its rear face (2 '), with at least one protruding assembly element (8) comprising a means (9) for engagement, for securing the trim piece (2) with the composite part (3) by applying the rear face (2 ') of the trim part (2) against the skin (6) of the composite part (3) and simultaneous introduction e of the element or of each assembly element (8) in the orifice or a corresponding through orifice (7) of the composite part (3) until it engages with the support (4), method characterized in what it consists in providing a support (4) comprising, at or at each location (10) corresponding to a location for drilling or milling a through hole (7), a recess or a recess (11) defining at least one shoulder or axial rim (12) with the rear face (4 ') of the support (4) opposite to the intermediate layer (5) and in that the operation of drilling or milling the orifice or each through hole (7) in the composite part (3) consists of digging from the apparent surface (3 ') of the composite part (3) until at least opening into the recess or hollow (11), while preserving a at least part of the shoulder or the rim (12) constituting the site of engagement of the assembly element (8) cor sponding. 2. Method according to claim 1, characterized in that the digging of each through orifice (7) is carried out by milling and in that the part (13) of each through orifice (7) resulting from the milling operation has a cross section (S) greater than that (S ') of the recess or hollow (11) contiguous. 3. Method according to claim 1 or 2, characterized in that the or each recess (11) of the support (4) has a side wall (1Γ) extending substantially perpendicularly from the rear face (4 ') of said support (4 ), and therefore also advantageously in the direction (D) of initial introduction of the milling tool (14), and constitutes a blind hole with a bottom wall (11), molded or added, and in that the digging operation of the corresponding through hole (7) removes at least said bottom wall (11). 4. Method according to any one of claims 1 to 3, characterized in that it consists in providing a trim piece (2) with several elongated assembly elements (8) each comprising an indexing surface (8 ' ) intended to come into abutment against the shoulder (12) of the through orifice (7) receiving the assembly element (8) considered and a means (9) for engagement intended to come into engagement by hooking or clipping on the rear face (4 ') of the support (4) in the final assembled state of the trim piece (2) with the composite piece (3). 5. Method according to any one of claims 1 to 4, characterized in that, during the movement of introduction of an assembly element (8) in a through orifice (7) during the operation of securing the trim piece (2) with the composite piece (3) machined by milling, said assembly element (8) is elastically deformed by interference from the engagement means (9), for example a hook or notch with a slope, with the shoulder or rim part (12) preserved. 6. Method according to claim 2, or any one of claims 3 to 5 insofar as it relates to claim 2, characterized in that the milling operation is carried out by a (e) milling tool or cylindrical cutter (14) comprising a cut on its circular part and a cut on its end and in that the milling operation comprises a descent of said cutter (14), and lateral movements of this cutter (14) to dig the whole of the bottom (11) of the recess or the recess (11) of the support (4), while preserving at least part of the side wall (1Γ) of said recess (11), the rotation of the milling operation causing chip evacuation. 7. Method according to any one of claims 1 to 6, characterized in that it consists, when the recess (11) of the support (4) is devoid of bottom, and is for example in the form of a tip - 12 or open tube segment (1Γ), to perform, before the formation of the intermediate layer (5) of foam, a preliminary operation of fitting a cover (15), in the form of a sticky film, on the 'open end of said tip (11') which is opposite the rear face (2 '), to form a bottom (H) · 8. Method according to any one of claims 1 to 7, characterized in that the trim piece (2) and the support (4) are made by molding of thermoplastic material, preferably each (e) in one piece. 9. Set (1) of two mutually assembled parts (2 and 3), comprising, on the one hand, a trim piece (2) provided, on its rear face (12 '), with at least one element of protruding assembly (8) and, on the other hand, a structural and / or covering composite part (3) constituted, successively from its rear face towards its front face, by a support (4), by an intermediate layer (5 ), advantageously molded, preferably made of foam, and by a skin (6) forming the apparent surface (3 ′) of said composite part (3), the assembly or joining connection between the two aforementioned parts (2 and 3) consisting of cooperation of at least one connecting element (8) projecting with at least one through hole (7) corresponding to the composite part (3), the or each connecting element (8) extending through the through hole (7) corresponding and comprising a means (9) engaging the support (4) at the rear face (4 ') of the latter, assembly (1) characterized in that the through hole (7) comprises a first part (13) hollowed out in the skin (6) and in the intermediate layer (5) and a second complementary part (12) formed by a shoulder or axial rim of the support (4), extending from the rear face (4 ') of said support (4) in the intermediate layer (5) and in the direction of the skin (6), and in that the or each connecting element (8) is, on the one hand, in lateral support against the shoulder (12) inside the through orifice (7) concerned and, on the other hand, in engagement with the rear face (4 ') of the support (4) by means of a corresponding suitable means (9). 10. The assembly of claim 9, characterized in that each shoulder (12) has an at least partially circumferential contour, for example substantially circular or elliptical, and in that each connecting element (8) is positioned in the orifice through (7) corresponding by lateral support against a portion of wall (11 ') - 13 projecting into the intermediate layer (5) from the substrate (4) and corresponding to the axial rim (12 ') of said shoulder (12), all of said covering elements (8) cooperatively securing by hooking under tension and indexed positioning of the trim piece (2) relative to the composite piece (3). 11. An assembly according to claim 9 or 10, characterized in that each assembly element (8) has a rod-shaped body with means (9) for engagement by hooking, for example a hook, advantageously formed at level or near the free end of said rod. 12. Assembly according to any one of claims 9 to 11, characterized in that it is obtained by means of the manufacturing process according to any one of claims 1 to 8. 13. Set of assembled parts according to any one of claims 9 to 12, characterized in that the composite part (3) is a dashboard of a motor vehicle. 14. Motor vehicle equipped with a set of assembled parts comprising a dashboard (3) receiving at least one trim piece (2), characterized in that this set of parts is a set of parts (1) according to the any of claims 9 to 13.