Motor vehicle bodywork element

Abstract

The invention relates to a motor vehicle bodywork element, the element consisting of a structural panel shaped as a box to which a skin panel fitted to the structural panel is attached, the structural panel and the skin panel being formed by injecting plastic material, wherein the structural panel and the skin panel are secured to one another via a strip of the plastic material, the strip being formed of at least one pair of ribs (66a, 66b, 68a, 68b), in particular arranged facing one another, respectively integral with the structural panel and / or the skin panel, welded to one another.

Description

[0001] TITLE: MOTOR VEHICLE BODYWORK COMPONENT.

[0002] Technical field of the invention

[0003] The invention relates to a bodywork component for a motor vehicle.

[0004] Technical background

[0005] The production of automotive body parts increasingly relies on the use of plastic materials. These materials offer numerous advantages: they allow for a wide variety of shapes, are easy to mold, are durable, and above all, are lightweight, which is a significant advantage in the context of weight reduction aimed at optimizing vehicle performance.

[0006] To achieve a substantial body panel extension, it is generally constructed as a structural body panel covered by one or more skin panels, which form the externally visible portion of the body panel. Both the structural panel and the skin panel are injection-molded from a plastic material, such as fiber-reinforced polypropylene.

[0007] Traditionally, the skin panel is joined to the structural panel using glue.

[0008] For this purpose, at least one initial bead of so-called "structural" adhesive is used, for example, a two-component polyurethane adhesive (PU2K), which is a slow-setting adhesive offering excellent bonding capabilities for these parts. When the assembly of the skin panel to the structural panel requires a watertight seal, this assembly is completed with a second bead of adhesive suitable for ensuring the seal. A non-structural, hot-melt polypropylene (PP) adhesive is used for this purpose.

[0009] However, polyurethane adhesives contain carcinogenic, mutagenic, or toxic compounds, known as CMR agents. It is therefore important to develop alternative approaches to eliminate, replace, limit, or improve adhesives containing such compounds.

[0010] One known assembly technique that eliminates the need for glue is laser welding. One of the parts is transparent to the laser, while the other is not. The laser beam produces a fusion reaction at the interface of the parts, allowing them to be joined.

[0011] However, this technique requires physical contact of the laser head with the transparent part and leaves a visible trace of the passage of the welding head on one of the parts without guaranteeing a seal between the parts.

[0012] There is therefore a real need for a structural panel in which the structural panel and the skin panel are bonded to each other, reducing or even eliminating the amount of glue used in such an assembly while preserving the aesthetic appearance of the parts.

[0013] Summary of the invention

[0014] The invention satisfies this need by providing a motor vehicle body component in which the box-shaped structural panel and the attached skin panel are joined by a welding process. To this end, the invention provides a motor vehicle body component, said component consisting of a box-shaped structural panel to which a skin panel attached to said structural panel is fixed, said structural panel and skin panel being formed by injection molding of plastic material, in which the structural panel and the skin panel are joined to each other by means of a bead of said plastic material, said bead being formed of at least one pair of ribs, in particular arranged opposite each other, originating from the material of said structural panel and / or with said skin panel, welded to each other.

[0015] The localized melting of opposing plastic ribs to form a weld bead allows for assembly using little or no glue, and free from the surface defects generated by laser welding. This is because the ribs are simply melted prior to assembly using a heating method that does not come into direct contact with the parts. The resulting weld enables assembly that is both fast and environmentally friendly.

[0016] According to various additional characteristics of the bodywork element according to the invention, which may be taken together or separately and which constitute so many embodiments of the invention:

[0017] - the foot of each rib, at its junction with said structural panel or said skin panel, is of a width between one third and one quarter of the thickness of said structural panel or said skin panel, - each rib made of material with said skin panel is of a thickness less than the corresponding opposite rib of the structural panel,

[0018] - The structural panel and the skin panel are fixed to each other by a structural assembly means, and a sealing means is interposed between the structural panel and the skin panel.

[0019] - the first of said welded ribs constitute the structural assembly means and in which the second of said welded ribs constitute said structural assembly means as well as the sealing means, said welded ribs constitute the structural assembly means and a sealing joint, made by applying a bead of glue between the structural panel and the skin panel, constitutes the sealing means,

[0020] - said adhesive is a non-structural, hot-melt polypropylene (PP) adhesive free of CMR agents. said welded ribs constitute the sealing means and a bead of two-component polyurethane adhesive (PU2K) applied between the structural panel and the skin panel constitutes the structural assembly means.

[0021] - in which the structural panel and the skin panel are made of fiber-reinforced polypropylene, including glass.

[0022] The invention also relates in particular to a door for a motor vehicle trunk, said door comprising a one-piece trunk door structure panel including:

[0023] - a lower section intended to be covered by an outer door panel,

[0024] - an intermediate part forming a rear window frame of the door, - an upper part forming a box, covered with a skin panel of an aerodynamic spoiler of the door, in which at least the upper part and the skin panel of the spoiler form a body structure element of the type described above.

[0025] According to various additional features of the lake gate according to the invention, which may be taken together or separately and which constitute so many embodiments of the invention:

[0026] - the upper part comprises a concave section equipped with longitudinal stiffeners and a perimeter surrounding said concave section,

[0027] - part of said stiffeners, the perimeter and the spoiler skin panel have said ribs welded opposite each other.

[0028] - the upper part receives a spoiler support extension, attached to the perimeter of said upper part and extending vertically to said rear window frame of the door, said spoiler support extension and said spoiler skin panel having at least one of said ribs facing welded.

[0029] The invention also relates to a method for manufacturing a motor vehicle body panel of the type described above, said method comprising at least: i) a step of forming the structural panel and said skin panel by injecting plastic material, ii) a step of assembling said structural panel and said skin panel, method in which:

[0030] - during the assembly step i) at least one protruding rib of the structural panel and one protruding rib of said skin panel are formed during plastic injection, said ribs being able to be positioned opposite each other,

[0031] - the assembly step ii) includes at least one phase of securing said skin panel to the structural panel comprising a sub-phase ii.a) during which the ribs are arranged opposite each other, a sub-phase ii.b) during which the plastic material of the free edges of said ribs is melted, then a sub-phase ii.c) during which said edges of said ribs are brought into contact and finally a sub-phase ii.d) during which the structural panel and said skin panel are pressed against each other so as to form a bead of said molten plastic material.

[0032] According to various additional features of the process according to the invention, which may be taken together or separately and which constitute so many embodiments of the invention:

[0033] - during sub-phase ii.a) the structural panel and the skin panel are respectively placed in their respective supports opposite each other,

[0034] - during sub-phase ii.b) the edges of the ribs are melted using infrared wires, infrared lamps, or an ultrasonic welding method,

[0035] - the assembly stage further includes a structural assembly phase of said skin panel to the structural panel and a phase of creating a seal between said skin panel and the structural panel,

[0036] - The structural assembly phase and the sealing joint creation phase are carried out by the bonding phase,

[0037] - sub-phases ii.a), ii.b), ii.c) and ii.d) are applied to at least two pairs of facing ribs, at least two of the facing ribs assembled forming a structural assembly and at least two other facing ribs assembled forming a sealing joint,

[0038] - the structural assembly phase is carried out by the bonding phase applied to a pair of facing ribs, and the sealing joint phase is carried out by applying a bead of non-structural, CMR-free, polypropylene (PP) hot melt adhesive to one of the structural or skin panels prior to sub-step ii.b),

[0039] - according to a variation of the process:

[0040] • Step ii.a) occurs before step ii.b),

[0041] • during step ii. b) a two-sided infrared heating element is introduced between said skin panel and the structural panel,

[0042] - the sealing joint creation phase is carried out by the bonding phase applied to a pair of facing ribs, and the structural assembly phase is carried out by applying a bead of two-component polyurethane adhesive (PU2K) to one of the structural or skin panels prior to sub-step ii.b),

[0043] - according to another variant of the process:

[0044] • Step ii.a) occurs before step ii.b)

[0045] • during step ii.b) a two-sided infrared heating element is introduced between the skin panel and the structural panel, with a thermally insulating mask interposed between said heating element and the bead of two-component polyurethane adhesive (PII2K) applied to one of the structural or skin panels.

[0046] Brief description of the figures. The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent from the following detailed explanatory description of at least one embodiment of the invention given by way of purely illustrative and non-limiting example, with reference to the accompanying schematic drawings, among which:

[0047] Figure 1 is an exploded perspective view of a rear door of a motor vehicle according to the invention;

[0048] Figure 2 is a perspective view showing the removal of the door from Figure 1 and elements of the metal inserts from that door;

[0049] Figure 3 is a perspective ghost view of the door structure panel fitted with its metal insert elements;

[0050] Figure 4 is a detailed top view of the door structure panel fitted with its metal insert elements;

[0051] Figure 5 is a schematic cross-sectional view of an intermediate part of the door structure panel;

[0052] Figure 6 is a detailed perspective view of a metallic insert according to the invention;

[0053] Figure 7 is a detailed perspective view of the door structure panel fitted with a metal insert element;

[0054] Figure 8 is a cross-sectional detail view of the door structure panel fitted with a metal insert element;

[0055] Figure 9 is a perspective view of the door structure panel fitted with its metal insert elements;

[0056] Figure 10 is a perspective view of the door structure panel fitted with a spoiler support extension;

[0057] Figure 11 is a perspective view of the spoiler support extension of Figure 10; Figure 12 is a perspective phantom view of the door structure panel fitted with its spoiler support extension;

[0058] Figure 13 is a side perspective view of the door structure panel fitted with its spoiler support extension;

[0059] Figure 14 is a longitudinal sectional side view of the door structure panel fitted with its spoiler support extension;

[0060] Figure 15 is a first detailed view of figure 14;

[0061] Figure 16 is a second detailed view of figure 14;

[0062] Figure 17 is a third detailed view of figure 14;

[0063] Figure 18 is a fourth detailed view of figure 14;

[0064] Figure 19 is a perspective view showing ribs connecting the structural panel and the spoiler support extension to the spoiler panel during peeling;

[0065] Figure 20 is a perspective view of a rib heating device, for bonding the structural panel and the skin panel of the door;

[0066] Figure 21 is a perspective view of one face of the rib-locking heating device of Figure 20;

[0067] Figure 22 is a detailed top view of the structural panel and the location of its connecting ribs;

[0068] Figure 23 is a cross-sectional view of a connecting rib;

[0069] Figure 24 is a schematic cross-sectional view of a first embodiment of the assembly of the structural panel to the skin panel of the door; Figure 25 is a schematic cross-sectional view of a second embodiment of the assembly of the structural panel to the skin panel of the door;

[0070] Figure 26 is a schematic cross-sectional view illustrating the realization of the second embodiment of the assembly of Figure 25;

[0071] Figure 27 is a schematic cross-sectional view of a third embodiment of the assembly of the structural panel to the skin panel of the door;

[0072] Figure 28 is a schematic cross-sectional view illustrating the realization of the third embodiment of the assembly of Figure 27;

[0073] Figure 29 is a block diagram illustrating the steps of a manufacturing process for a motor vehicle body component according to the invention; and

[0074] Figure 30 is a block diagram illustrating the steps of a manufacturing process for a structural panel according to the invention.

[0075] Detailed description of the invention

[0076] Figures 1 and 2 show a motor vehicle body element 10, specifically in this case a door 10 for a motor vehicle trunk. The door 10 extends longitudinally along direction X, transversely along direction Y, and vertically along direction Z. The body element 10 preferably has a length and width much greater than its thickness, in particular by a factor of at least ten.

[0077] The element or door 10 comprises a structural panel, here a door structural panel 12 for a trunk. This door structural panel 12 includes, for example: - a lower part 14 intended to be covered by an outer door panel 16,

[0078] - an intermediate part 18 forming a frame 20 for a rear window, intended to be covered by a rear window (not shown) of the door, this intermediate part defining two arms 22 on either side of the frame 20, and / or

[0079] - an upper part 24, intended to be covered by a skin panel 26 of an aerodynamic spoiler of the door 10. It should be noted that the upper part 24 could, alternatively, be covered by a part of the rear window.

[0080] More specifically, the upper part 24 forms a box supporting the skin panel 26, which is fixed to it. The upper part 24 includes, in particular, a concave portion 34 and a perimeter 36 surrounding said concave portion, as can be better seen in figures 3, 4, 9, 10, 12 and 22.

[0081] The skin panel 26 is preferably formed by injection of plastic material.

[0082] According to one aspect of the invention, as illustrated in Figure 3, the structural panel 12 comprises a main extension portion, here divided into three zones 15, 17, 23 corresponding respectively to said lower portion 14, intermediate portion 16 and upper portion 24. The panel 12 further comprises a reinforcement element 28 defined by a rib 30 extending projecting over said main extension portion.

[0083] The reinforcing element 28 extends at least into the intermediate portion 18 and the upper portion 24. Preferably, this reinforcing element 28 extends from the lower portion 14 to the upper portion 24 via the intermediate portion 18. In this way, the reinforcing element 28 extends over each of the zones 15, 17, 23 of the main extension portion. In the intermediate portion 18, the element 24 includes at least one portion 29 with axis A, laterally bordering the rear window frame 20, as can be seen more particularly in Figure 3.

[0084] The main extension section 15, 17, 23 and the rib 30 are monobloc and / or jointly produced in a single piece by injection molding of a plastic material such as polypropylene. This plastic material is reinforced with fibers, in particular glass fibers.

[0085] As schematically illustrated in Figure 5 and Figures 7 and 8, the reinforcing element 28 is hollow and is formed by injecting a fluid after the injection of the plastic material into the main extension portion of the structural panel 12 of the door 10, thus defining a vein 32 inside the rib 30. A vein is defined as a shape whose cross-section has a closed contour. The load-bearing fibers 25 can be seen in Figure 5.

[0086] A problem can arise during the molding of the structural panel 12. The hollow core, which extends throughout the entire reinforcement element 28, is created during the molding process. This process involves filling a mold that matches the shape of the structural panel and the solid reinforcement element, then injecting the plastic material. Before this plastic material has completely solidified, the reinforcement element 28 is hollowed out by injecting a pressurized fluid. Because the reinforcement element is solid, its periphery is already solidified while its core is still molten. It can therefore be hollowed out by injecting fluid into its molten core, which forces out the unsolidified plastic. The result of this operation is a reinforcement element 28 that is both hollow and rigid.

[0087] However, it has been observed that the size of the vein and in particular its cross-section is significantly larger than the surrounding areas and concentrates more oriented fibers, thus creating a greater constriction phenomenon which generates deformations which take precedence over the deformations commonly observed.

[0088] This results, in the absence of specific provisions of the invention, in the cooling of the reinforcing element 28, in the shrinkage of the reinforcing element 28 along a direction T, transverse to the direction of the reinforcing element. This phenomenon is further amplified in areas such as the intermediate zone 18, where the geometry of the panel itself causes the fibers 25 to be oriented in a direction parallel to that of the rib 30, i.e., along the axis A of the intermediate part 18. Upon cooling, the reinforcing element 28 deforms and no longer conforms to the desired dimensions.

[0089] This deformation is likely to propagate to any surrounding part of the structural panel 12, and in particular risks deforming in an unpredictable way the intermediate part 18 and a bottom wall 35 of the concave part 34 of the upper part 24.

[0090] The invention remedies these drawbacks by reinforcing these areas, in particular the middle part 18 and the upper part 24 to counteract this shrinkage phenomenon, as will be developed later.

[0091] Regarding the upper part 28, alternatively or cumulatively, parallel longitudinal stiffeners of rigidity 38 extend from the bottom wall 35 of the concave part 34. These stiffeners 38 have been shown more particularly in figures 4, 9, 10 and 12 to 18 and 22. They are advantageously made of the same material and molded with the structural panel 12.

[0092] As these figures illustrate in particular, the stiffeners are oriented substantially along the X direction of the door 10, and cross the entire concave part 34 from a front edge 36a to a rear edge 36b of the perimeter 36. As can be seen in particular in figure 12, the longitudinal stiffeners 38 have longitudinal ends 38a, 38b respectively joined with the front edge 36a and rear edge 36b of the perimeter 36.

[0093] As can be seen in Figures 2 and 14, the spoiler skin panel 26 is fixed at least around its perimeter 36. Preferably, the spoiler skin panel 26 is also fixed to all or part of the longitudinal ends 38a, 38b of the longitudinal stiffeners. The details of the practical implementation of this fixing will be described later in this description.

[0094] Advantageously, the stiffeners 38 are at least locally of a determined height h which is less than a depth H of the cavity 34. In this way, as illustrated in figure 13, the stiffeners 38 define in the cavity 34 a passage P, represented by dashed lines in figure 13, allowing, for example, the passage of an electrical bundle (not shown) between the stiffeners 38 and the spoiler skin panel 26. Preferably, the stiffeners 38 have said height h, limited, over a part of their length and are flush with said cavity over another part, at least for some of said stiffeners.

[0095] Advantageously, as illustrated in Figures 9 and 10, transverse partitions 40 can pass through the cavity 34 to connect the stiffeners 38 so as to further stiffen the structural panel 12. These partitions 40 are also advantageously made from the same material and molded with the panel 12, and are particularly visible in Figures 10, 12 and 13.

[0096] As can be seen in Figures 2, 3, and 9, the upper part 24 has anchor points 42 for the hinges of the door 10 at its transverse ends 44. Preferably, the stiffeners 38 are distributed transversely in the cavity with a higher density near these anchor points, as can be seen in Figures 4, 9, and 22. As can be seen in these figures, the stiffeners 38 are less spaced near the anchor points 42. This configuration allows for optimal support of the stresses induced in the material of the door 10 by the hinge anchor points 42.

[0097] A particularly advantageous door configuration

[0098] 10 is that it is capable of receiving indifferently spoiler skin panels 26 of different lengths, and in particular spoiler skin panels 26 of great lengths. For this purpose, the door 12 can include a spoiler support extension 46, which is attached to the rear edge 36b of the perimeter 36, and which extends vertically along the frame 20 of the rear window of the door 12, as shown in figures 9 to 14, 19 and 22.

[0099] As can be seen in figures 10 and 11, 12 and 19, the spoiler support extension 46 preferably also includes longitudinal ribs 48, or even partitions 50 between these ribs, which increase the rigidity of the spoiler support extension 46.

[0100] The spoiler support extension 46 does not necessarily occupy the entire width of the upper portion 18. To provide sufficient support for the spoiler skin panel 26,

[0101] 11 It is sufficient that the spoiler support extension 46 extends transversely along a part of a width of the rear edge 36b of the perimeter 36, as can be seen in particular in figures 9 and 12. As can be seen in particular in figure 14, the spoiler skin panel 26 extends at least to a free end 52 of the spoiler support extension 46.

[0102] The spoiler support extension 46 is fixed to the upper part 24. For this purpose, as illustrated in Figures 11 to 13, the spoiler support extension comprises, from its end 52 towards the upper part 18: - a first portion 54, in particular straight, which extends rearward from the rear edge 36b of the perimeter 36, in line with it

[0103] - at least one clamp 56 extending from said first portion 54, pinching the rear edge 36b of the perimeter 36,

[0104] - a second portion 58 which extends under the rear edge 36b of the perimeter 36 from the first portion 54,

[0105] - at least one fixing bracket 60 extending under the upper part from said second portion 58 and fixed to the upper part, in particular by screwing, stapling, or welding. The two fixing brackets 60 shown here also serve to form a stop for the spoiler support extension 46 against the structural panel 12 along the X direction.

[0106] The spoiler support extension 46 can therefore be easily and reliably mounted at the end 36b of the perimeter 36, depending on the spoiler skin chosen. As shown in Figure 11, the spoiler will be closed under the spoiler skin extension by a trim piece 62, attached to the spoiler support extension 46.

[0107] Typically, the assembly of the spoiler skin panel 26 to the structure panel 12 is carried out using glue or by means of a screwed multi-component spoiler.

[0108] For this purpose, at least one initial bead of so-called "structural" adhesive is used, for example, a two-component polyurethane adhesive (PU2K), which is a slow-setting adhesive offering excellent bonding capabilities for these parts. This initial bead of adhesive is located, for example, around the perimeter 36 of the structural panel.

[0109] Since the assembly of the spoiler skin panel 26 to the structural panel 12 requires a seal when this spoiler skin panel is glued, this assembly is conventionally completed with a second bead of glue suitable for ensuring a seal.

[0110] However, polyurethane adhesives contain carcinogenic, mutagenic, or toxic compounds, known as CMR agents. According to a third aspect of the invention, which can be used alone or in combination with one or more of its previous aspects, the invention aims to develop alternative approaches to eliminate, replace, limit, or improve adhesives containing such compounds.

[0111] For this purpose, as schematically shown in Figures 24, 25, and 27, the structural panel 12 and the spoiler skin panel 26 are joined to each other by means of at least one bead 64 of said plastic material. As schematically illustrated in Figures 26 and 28, this bead is formed of at least one pair of ribs 66, 68, arranged opposite each other, which are respectively formed from said structural panel 12 and the skin panel 26, and which are welded to each other. In other words, the bead 34 is formed of welded portions of said ribs 66, 68.

[0112] It will be understood that such an assembly is applicable to the manufacture of any structural element comprising a structural panel 12 and a skin panel 26 in the general sense, and not limited to the door 10.

[0113] To do this, as illustrated in Figure 29, the bodywork element, here the door 10, can be produced according to a process comprising at least one step i) of forming the structural panel 12 and said spoiler skin panel 26 by injection of plastic material, and one step ii) of assembling said structural panel 12 and said spoiler skin panel 26.

[0114] During the assembly step ii) at least the projecting rib 66 of the structural panel 12, and the projecting rib 68 of the spoiler skin panel 26 are formed during plastic injection. These ribs 66 and 68 are respectively formed from the material of the structural panel 12 and the spoiler skin panel 26.

[0115] Ribs 66, 68 are suitable for being arranged opposite each other, as schematically illustrated in figures 26 and 28.

[0116] Within the framework of the invention, as illustrated in Figures 26, 28, and 29, assembly step ii) comprises at least one phase P1 for securing said spoiler skin panel 26 to the structural panel 12, comprising a sub-phase ii.a) in which the ribs 66, 68 are arranged opposite each other, a sub-phase ii.b) in which the plastic material of the free edges 70, 72 of said ribs 66, 68 is melted, then a sub-phase ii.c) (not shown) in which said edges 70, 72 of said ribs 66, 68 are brought into contact, and finally a sub-phase ii.d) (not shown) in which the structural panel 12 and the spoiler skin panel 26 are pressed against each other so as to form the 34 cord of melted plastic material.

[0117] More specifically, during sub-phase ii.a) the structural panel 12 and the spoiler skin panel 26 are respectively placed in respective supports 74, 76 opposite each other.

[0118] Figure 20 represents a fastening device 78 allowing the structural panel 12 of the aforementioned trunk door to be fastened to the spoiler skin panel 26. It includes the support 76, or lower support, on which the structural panel 12 rests, and the upper support 78, intended to carry the spoiler skin panel (not shown in Figure 20). The device 78 further includes a two-sided heating device 82 84, 86, each side of which is equipped with a heating means 88 suitable for melting the free edges 70, 72 of the ribs 66, 68. As illustrated in Figure 21, the heating means 88 can be infrared wires 90, but it could also be infrared lamps, or an ultrasonic welding means, suitable for melting the free edges 70, 72 of the ribs 66, 68 during sub-phase ii. b).

[0119] To ensure optimal weldability of the ribs 66, 68, as illustrated in Figure 23, a foot 91 of each rib 66, 68, at its junction with the structural panel 12 or the skin panel 26, is of a width I which is between one third and one quarter of a thickness E of said structural panel 12 or of said skin panel 26.

[0120] The rib(s) 66, 68 may have an inclined, non-perpendicular orientation with respect to the structural panel 12 or with respect to the spoiler skin panel 26 from which they originate. Advantageously, ribs joined to each other by welding have the same inclination and are substantially in the same plane.

[0121] Furthermore, in order to obtain a weld bead 64 of minimum thickness, it is not necessary for the ribs 66, 68 to be of the same thickness, based on the panels from which they originate. In this context, each rib 68 originating from the skin panel 12 preferably has a thickness less than the corresponding rib 66 of the structural panel 12. Advantageously, therefore, of the two ribs 66, 68 welded to the other, one penetrates the other.

[0122] Another characteristic of the motor vehicle body element 10 according to this third aspect of the invention, and in particular of the door 10, is that the structural panel 12 and the spoiler skin panel 26 are on the one hand fixed to each other by a structural assembly means and that on the other hand, a sealing means is interposed between the structural panel 12 and the spoiler skin panel 26.

[0123] Thus, the assembly step ii) further comprises a phase P2 of structural assembly of the spoiler skin panel 26 to the structure panel and a phase P3 of making a sealing joint between the spoiler skin panel 26 and the structure panel 12.

[0124] As seen above, conventionally, during the assembly step ii) the fixing of the structural panel 12 to the spoiler skin panel 26 is ensured by a first bead of so-called "structural" glue, for example a two-component polyurethane glue (PU2K), while the sealing between these panels 12, 26 is ensured by a second bead of non-structural, hot-melt polypropylene (PP) glue.

[0125] The weld bead 66 produced during the bonding phase occurring during step ii) can advantageously perform one, the other, or all of these functions in accordance with the third aspect of the invention.

[0126] Thus, according to a first embodiment of the assembly, the first of said welded ribs 66a, 68a constitute the structural assembly means, and the second of said welded ribs 66b, 68b constitute the sealing means.

[0127] In this case, each phase P2 of structural assembly of the skin panel 26 to the structure panel 12 and each phase P3 of making a sealing joint correspond to the phase P1, mentioned above, of securing said spoiler skin panel 26 to the structure panel 12.

[0128] Sub-phases ii.a), ii. b), ii.c) and ii.d) are therefore applied to at least two pairs 66a, 68a and 66b, 68b of facing ribs, at least two of the facing ribs 66a, 68a assembled forming a structural assembly, and at least two other of the facing ribs 66b, 68b assembled forming a sealing joint.

[0129] This configuration is shown in Figures 19 and 22. Figure 19 shows the locations of the structural assembly ribs 66a of the structural panel 12 and the sealing ribs 66b of the structural panel 12, opposite which are the locations of the structural assembly ribs 68a of the skin panel 26 and the sealing ribs 68b of the spoiler skin panel 26. It should be noted that the structural assembly ribs 66a of the structural panel 12 are essentially formed from the upper portion of all or part of the stiffeners 38 and the partition 40. They are positioned here on some of the stiffeners 38 and on parts of the partition 40 in a U-shape, and / or also on the spoiler support extension 46. The sealing ribs 66b of the structural panel 12, as for They run along the entire perimeter 36.

[0130] Figure 22 shows only the locations of the structural assembly ribs 66a of the structural panel 12 and the sealing ribs 66b of the structural panel 12.

[0131] Figures 15 to 18 illustrate more specifically the locations of the structural assembly ribs 68a of the skin panel 26 on the stiffeners 38.

[0132] As can be seen in Figure 15, the front edge 36a of the perimeter 36 has a sealing rib 66b and the front end 38a of the stiffener 38 has a structural assembly rib 66a. Figure 16 shows the sealing rib 66b of the rear edge 36b of the perimeter 36, above the spoiler support extension 46. Figure 17 shows the structural assembly rib 66a of the rear end 38b of the stiffener 38. Finally, Figure 18 shows the structural assembly rib 66a of the spoiler support extension 46. According to the second and third embodiments of the assembly, as illustrated in Figures 25 to 28, the weld bead 66 produced during the joining phase occurring in step ii) may only provide structural fixing or only sealing.

[0133] Thus, in the case of the assembly in Figure 25, in the second embodiment of the assembly, the welded ribs forming the bead 34 constitute the sealing means and a bead of two-component polyurethane adhesive 92 (PU2K) is applied between the structural panel 12 and the skin panel 26 to constitute the structural assembly means.

[0134] In this case, only phase P3 of creating a sealing joint corresponds to phase P1.

[0135] The sealing joint P3 phase is therefore carried out by the bonding phase P1 applied to a pair of ribs 66b, 68b opposite, and the structural assembly phase P1 is carried out by applying the bead of two-component polyurethane adhesive 92 (PU2K) to one of the structural panels 12 or skin panel 26 prior to sub-step ii.b), in this case the structural panel 12, as shown in figure 26.

[0136] Preferably, sub-phase ii.a), during which the ribs 66b, 68b are arranged opposite each other, takes place before sub-phase ii.b), during which the free-edge plastic material 70, 72 of said ribs 66b, 68b is melted. During sub-phase ii.b), the two-sided heating device 82 84, 86 is introduced between the skin panel 12 and the structural panel 26, with a thermally insulating mask 94 interposed between the heating device 82 and the two-component polyurethane (PII2K) adhesive bead 92 applied to the structural panel 12. The purpose of this mask 94 is to prevent the heating device from causing the adhesive bead 92 to harden before the ribs 66b, 68b are melted and assembled.

[0137] Thus, in the case of the assembly in Figure 27, in the third embodiment of the assembly, the welded ribs 66a, 68a forming the bead 34 constitute the structural assembly means and a bead of non-structural, hot-melt polypropylene (PP) glue 94 without CMR agents is applied between the structural panel 12 and the skin panel 26 to constitute the sealing means.

[0138] In this case, the structural assembly phase P2 is carried out by the bonding phase P1 applied to a pair of facing ribs 68a, 68b, and the sealing joint phase P3 is carried out by applying the hot melt adhesive bead 94, polypropylene (PP), non-structural, without CMR agents, on one of the structural panels 12 or skin panel 26 prior to sub-phase ii. b), in this case the skin panel 12.

[0139] In the same way as before, preferably sub-phase ii.a), during which ribs 66a, 68a are arranged opposite each other, occurs before sub-phase ii.b).

[0140] During sub-phase ii.b) the plastic material of free edges 70, 72 of said ribs 66a, 68a is melted. The two-sided heating device 82 84, 86 is introduced between the skin panel 12 and the structural panel 26, with or without a thermally insulating mask, because the setting time of the hot melt, polypropylene (PP), non-structural adhesive bead 94 is much longer and the adhesive bead is not likely to be affected by the heating device 82.

[0141] As previously seen, the invention, in particular according to its first aspect, aims to remedy the disadvantages of the shrinkage phenomenon caused by the orientation of the fibers during the production of the hollow reinforcement element 28, defined by the rib 30 traversed by the hollow vein 32, extending, in the illustrated embodiment, over the zones 15, 17 and 23 of the main extension part at the level of the lower 14, intermediate 18 and upper 24 parts of the door 10.

[0142] Since the reinforcing element 28 and the main extension portion are, as already mentioned, produced jointly by injecting the fiber-reinforced plastic material, the invention proposes to remedy the transverse shrinkage phenomenon caused by the orientation of the fibers 25 during the molding of the reinforcing element 28 by reinforcing it, particularly during the solidification of the plastic material. To this end, as illustrated in Figures 1 to 5 and 7 to 9, the structural panel 12 includes a metal insert element 98 which is overmolded by the plastic material at least along a portion of said rib 30.

[0143] By "overmolded" we mean that the plastic material is present around the insert element, following a molding, without necessarily covering the entire surface of the metal insert element 98. In this way, by observing said panel, it is possible to see locally the metal insert element 98 in areas where it is not covered with plastic material, while remaining within the scope of the first aspect of the invention.

[0144] More specifically, the metal insert element 98 has at least a first part 100 which is overmolded between the main extension part, in particular at the level of the zone 17 of the intermediate part 18, and the reinforcement element 28.

[0145] As illustrated in particular by Figures 7 and 8, the first portion 100 extends along one side of the rib 30. The first portion 100 is thus able to counteract the shrinkage phenomenon during the solidification of the plastic material. Preferably, the rib 30 has a rectangular or square cross-section. The first portion 100 extends along one side of the rectangular or square cross-section, as schematically shown in Figure 7. Thus, the first portion of the metal insert element comprises at least one substantially flat wall 102, extending along one side of said rib 30.

[0146] Furthermore, as can be seen in Figure 6, the first part 100 of the metal insert element 98 has at least one hole 104 through which the plastic material from the reinforcing element 28 passes.

[0147] Furthermore, the first portion 100 of the metal insert element 98 is covered, in whole or in part, with plastic material from the main extension portion 17, specifically by a network of intersecting plastic ribs 106. The material of these ribs 106 communicates, for example, with the material of the rib 30 through the perforations 104. In other words, the perforations 104 allow the passage of plastic material to facilitate the filling of the ribs 106. It will therefore be understood that an injection mold for the panel 12 will have grooves suitable for forming the ribs 106. The ribs 106 can take any useful shape and are, for example, intersecting.

[0148] In other words, the rib network 106 is located on one face of the metal insert element 98, and on the opposite face, continuous through the holes 104, the remainder of the main extension portion of the panel 12 extends continuously. Put another way, on the side of the rib network 106, the metal insert element 98 is visible between the ribs of the rib network 106, while on the opposite side, it is embedded in the plastic material of the panel 12. In the door 10 according to the invention, the first portion 100 of the metal insert element 98 is located substantially on the intermediate portion 18 along axis A.

[0149] As can be seen in Figures 6 to 8, the metal insert element 98 also includes a second part 108, adjacent to the first part 100, which extends into the intermediate section 18 of the structural panel 12 opposite the rear window frame 20, specifically from one of its lateral sides, which is locally shortened. This second part 108 is shaped into a wing extending parallel to axis A. One end 107 of this second part 108 has a hole 110, suitable for receiving a fixing element 112 of a door cylinder ball joint 114, as shown in Figure 8.

[0150] As illustrated in Figures 2 to 4, the metal insert element 98 further comprises a third part 1 16, adjacent to the first part 100, which extends into the upper part 24 of the structural panel 12 and, which extends transversely with respect to the axis A. The metal insert element 98 locally defines at this level an L-shaped tab having at least one hole 1 18 suitable for being passed through by a screw (not shown) for fixing a hinge of the door, visible in Figure 2.

[0151] As can be seen in figures 6 to 9, the overmolded metal insert element 98 further comprises a fourth part 120, adjacent to the first part 100, which extends into the intermediate part 18 of the structural element 12 towards the rear window frame 20 and which has a vertical wing shape.

[0152] Thus, the first, second and fourth parts 100, 108 and 120 of the metal insert element 98 define a gutter with a substantially U-shaped cross-section. In other words, on either side of said rib 30, said insert element 98 extends by lateral sides so as to present a substantially U-shaped profile, a bottom wall of the profile forming the part of the insert element located opposite the rib 30.

[0153] Here, the rib network 106 extends at the level of the said lateral flank(s), at the level of the said first face of the insert element 98. The remainder of the said main extension part extends, for example, over the entire opposite face of the metal insert element 98.

[0154] As illustrated in Figure 30, the structural panel 12 can be manufactured using a process comprising, firstly, step I) in which a plastic injection mold is prepared, consisting of two shells (not shown) defining the overall shape of the structural panel 12. The shells also define a cavity constituting a counter-form of the reinforcing element 24 of said structural panel, and two ends of said cavity opening outside said mold. Then, in step II) the insert element 98 is placed in the mold, between the two shells. It should be noted that, preferably, the mold advantageously includes means for positioning the insert element 98 relative to the cavity, so as to define a unique position for the insert element 98.

[0155] Then, in step I (II), a plastic material is injected into the mold, allowing the element 28 to be overmolded. Finally, in step IV), before the plastic material has fully polymerized, a fluid is injected at one end of the cavity to hollow out the reinforcing element 24, forming the hollow channel 32 within the rib 30. Thanks to the insert element 98, the fiber orientation phenomenon that could occur during the creation of the channel is limited. The invention is particularly applicable to a vehicle door 10, thus offering high rigidity characteristics and reduced weight.

Claims

DEMANDS 1. Motor vehicle bodywork element, said element consisting of a box-shaped structural panel (12) to which a skin panel (26) attached to said structural panel (12) is attached, said structural panel (12) and skin panel (26) being formed by injection of plastic material, in which the structural panel (12) and the skin panel (26) are joined to each other by means of a cord (64) of said plastic material, said cord being formed of at least one pair of ribs (66, 66a, 66b, 68, 68a, 68b), in particular arranged opposite each other, respectively formed from material with said structural panel (12) and / or with said skin panel (26), welded to each other.

2. Motor vehicle bodywork element according to the preceding claim, wherein a foot 91 of each rib (66, 68), at its junction with said structural panel (12) or said skin panel (26), is of a width (I) between one third and one quarter of a thickness (E) of said structural panel (12) or said skin panel (26).

3. Motor vehicle bodywork element according to any one of the preceding claims, wherein each rib (68, 68a, 68b) made of material with said skin panel (26) is of less thickness than the corresponding opposite rib (66, 66a, 66b) of the structural panel (12).

4. A motor vehicle body component according to any one of the preceding claims, wherein the structural panel (12) and the skin panel (26) are fastened to each other by a structural assembly means and wherein a means a sealing layer is interposed between the structural panel (12) and the skin panel (26).

5. Bodywork element according to the preceding claim, wherein first of said welded ribs (66a, 68a) constitute the structural assembly means and wherein second of said welded ribs (66b, 68b) constitute said structural assembly means as well as the sealing means. 6 Bodywork element according to claim 4, wherein said welded ribs (66a, 68a) constitute the structural assembly means and wherein a sealing joint, made by application of a bead of glue (94) applied between the structural panel (12) and the skin panel (26), constitutes the sealing means. 7 Bodywork element according to claim 4, wherein said welded ribs (66b, 68b) constitute the sealing means and wherein a bead of two-component polyurethane adhesive (92) (PII2K) applied between the structural panel (12) and the skin panel (26) constitutes the structural assembly means.

8. Door (10) for a motor vehicle trunk, said door (10) comprising a one-piece trunk door structure panel (12) comprising: - a lower part (14) intended to be covered by an outer panel (16) of the door (10), - an intermediate part (18) forming a frame (20) for the rear window of the door, - an upper part (24) forming a box, covered with a skin panel (26) of an aerodynamic spoiler of the door in which at least the upper part (24) and the spoiler skin panel (26) form a body structure element according to any one of claims 1 to 7.

9. Door (10) according to the preceding claim, in which the upper part (24) comprises a concave part (34) provided with longitudinal stiffeners (38) for stiffening and a perimeter (36) surrounding said concave part (34).

10. Door (10) according to the preceding claim, in which a part of said stiffeners (38), the perimeter (36) and the skin panel (26) of spoiler have said ribs (66a, 68a; 66b, 68b) facing welded. 1 1. Door (10) according to any one of claims 9 to 10, wherein the upper part (24) receives a spoiler support extension (46), attached to the periphery (36) of said upper part (24) and extending vertically below said rear window frame (20) of the door, said spoiler support extension (46) and said spoiler skin panel (26) having at least one of said ribs (66a, 68a; 66b, 68b) welded opposite each other.

12. A method for manufacturing a motor vehicle body component according to claim 1, said method comprising at least: i) a step of forming the structural panel (12) and said skin panel (26) by plastic injection, ii) a step of assembling said structural panel and said skin panel, method wherein: - during the assembly step ii) at least one rib (66a, 66b) projecting from the structural panel (12), and one rib projecting from said skin panel (26) are formed during plastic injection, said ribs being (66a, 68a; 66b, 68b) capable of being positioned opposite each other, - the assembly step ii) comprises at least one bonding phase P1 of said skin panel to the structural panel (12) comprising a sub-phase ii.a) during which the ribs (66a, 68a; 66b, 68b) are arranged opposite each other, a sub-phase ii.b) during which the plastic material of the free edges (70, 72) of said ribs (66a, 68a; 66b, 68b) is melted, then a sub-phase ii.c) during which said edges (70, 72) of said ribs (66a, 68a; 66b, 68b) are brought into contact, and finally a sub-phase ii.d) during which the structural panel (12) and said skin panel (26) are pressed together so as to form a bead (64) of said melted plastic material.

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