Exterior tailgate panel of motor vehicle

Abstract

The invention relates to an exterior panel (20) for a motor vehicle tailgate intended to be bonded to a lining, the exterior panel (20) comprising: - a main body, - a recess forming a housing for a light assembly and comprising a back wall, and - a bonding wall (32) extending from the back wall and comprising an end portion (36) connected to an upper edge (26) of the exterior panel (20), - a first connecting wall (40) extending from the end portion (36) of the bonding wall (32) to an inner face of the main body (22) so as to form a second bonding ramp for the exterior panel (20), one end (44) of the first connecting wall (40) fixed to the inner face of the main body having a thickness less than that of the upper wall (27) of the main body. Figure for the abstract: Figure 5

Description

Title of the invention: Exterior tailgate panel of a motor vehicle

[0001] The invention relates to motor vehicle tailgates made of plastic comprising an outer panel and a lining, and more particularly to the outer panels of such tailgates.

[0002] Figures 1 to 3 illustrate a tailgate 2 according to the prior art. Certain body parts, for example the tailgate 2 of [Fig. 1], usually comprise a lining 4 (or inner panel) constituting the structural part of the body part and an outer panel 6 constituting an exterior skin. The lining 4 and the outer panel 6 are generally joined by bonding. A bead of adhesive 8 can therefore be deposited on the periphery of the inner face of the outer panel to achieve this joining. To this end, it is known that, in certain configurations, the outer panel includes at least one bonding wall 10 forming a glue-receiving ramp (or bridge) onto which a portion of the adhesive bead 8 disposed on the outer panel is deposited.

[0003] Generally, the bonding wall 10 can extend along a side wall 12 of the outer panel, one of its sides 10' being connected to this side wall 12. A second side 10" of the bonding wall 10, opposite side 10', is not connected to any wall. The bonding wall 10 can, for example, extend from the bottom walls 14 and 14' of a recess 16 formed at the left 11 and right 11' ends of the outer panel 6 and forming a housing for a lens unit (these two parts are visible in [Fig. 1]), to reach the upper wall 18 of the outer panel 6, the upper wall being located under the window of an assembled tailgate. In other words, a section of the adhesive bead 8 is deposited on the portion of the bonding wall 10 extending from the upper edge of the inner face 15 from the bottom wall 14 (which is part of the inner face 17 of the outer panel 6) until joining the inner face 17 of the upper wall 18.The bonding wall 10 thus forms a transition slope with the smallest possible angular variation between the bottom wall 14 of the recess 16 and the top wall 18. This configuration ensures homogeneous bonding by preventing the deposited adhesive bead 8 from being degraded or even forced out of certain areas to be bonded during assembly by contact under assembly stress between the outer panel 6 and the lining 4, due to inadequate angular positioning between the different areas / surfaces involved in the bonding. This, for example, prevents areas / surfaces of the outer panel coated with adhesive from extending in a significantly different direction. parallel to the assembly direction of the outer panel and the lining. It is advantageous for the angle formed by the bonding wall 10, creating the transition slope, and the bonding direction of the outer panel 6 to the lining 4 to be greater than or equal to 30° in order to achieve the desired effect. This ensures good local bonding between the outer panel and the lining and applies uniform bonding pressure along the entire adhesive bead.

[0004] The bonding wall 10 comprises, in the configuration of [Fig. 2] and [Fig. 3], an upper end 13 connected to the inner face 17 of the upper wall 18 of the outer panel 6, the adhesive bead 8 being deposited on the bonding wall 10 and then extending from the latter to said inner face 17, as can be seen in Figures 2 and 3. This leads to an aesthetic drawback. Indeed, the connection of the bonding wall 10, by its upper end 13, to the inner face 17 of the outer panel 6 results in a degradation of appearance due to the molding, visible on the outer face 19 of the upper wall 18 of the outer panel opposite the area where the bonding wall 10 connects to the inner face 17 of the upper wall 18.

[0005] To mask this defect, known as "shrinkage", it is known to create a style line at the level of the area of ​​the outer panel presenting an appearance defect, at the end 13, for example by making a local change of shape of the outer panel as can be seen in [Fig.3], by creating an angular discontinuity on the outer face 19.

[0006] However, some car manufacturers are unwilling to allow stylistic adaptations to conceal a cosmetic defect. Therefore, it is no longer possible to consider connecting the bonding wall at an upper end 13 to the middle of the inner face of the outer panel in such a way as to create a cosmetic defect on the outer face of the outer panel (i.e., in an area requiring the implementation of devices to conceal a cosmetic defect).

[0007] The invention aims in particular to provide an outer panel that can be glued to a lining without generating any appearance defect in the resulting tailgate and without adapting the style, while ensuring a seal of an internal volume located between the outer panel and the lining, this seal being locally achieved by their assembly with the use of the glue bead at the level of a corner of the outer panel.

[0008] To this end, the invention relates to an exterior tailgate panel for a motor vehicle intended to be glued onto a lining, the exterior panel being made of plastic and comprising: - a main body comprising at least one side wall and one top wall, - a recess forming a housing for an optical block and comprising a back wall, - a bonding wall extending from the back wall and along the side wall, comprising a first side connected to the side wall, and comprising a terminal portion connected to an upper edge of the top wall, the bonding wall forming a first bonding ramp for the outer panel onto a lining, - a first connecting wall extending at the terminal portion of the bonding wall, from a second side of the bonding wall opposite the first side of the bonding wall connected to the side wall, to an internal face of the upper wall of the main body so as to form a second bonding ramp of the outer panel onto a lining, one end of the first connecting wall fixed to the internal face of the upper wall of the main body having a thickness less than that of the upper wall of the main body.

[0009] Thus, the resulting structure both prevents the appearance of surface defects on the outer face of the outer panel and ensures continuity in the application of the adhesive bead. First, the connection of the bonding wall to the upper edge of the outer panel allows for a bond at the edge of the part rather than across the entire surface. This avoids the appearance of shrinkage cavities, and therefore the need to create a style line in the area of ​​the outer panel exhibiting a surface defect. Furthermore, the first bonding wall extending from the bonding wall towards the inner face of the outer panel ensures surface continuity of the bonding wall at its terminal portion, and thus continuity in the application of the adhesive bead.Finally, the connection of this first bonding wall with the inner face of the outer panel is of a lesser thickness, which prevents the appearance of a defect without risk of breakage of this connection because the bonding pressure is exerted on the bonding wall at the point of its connection to the upper edge of the outer panel.

[0010] Depending on other optional features of the exterior panel taken alone or in combination: - the thickness of the end of the first connecting wall fixed to the inner face of the main body is between 10% and 15% of that of the upper wall of the main body, - the angle between the first connecting wall and an external face of the main body is between 60° and 90°, - the outer panel includes a second connecting wall linked to the first connecting wall, the bonding wall and the inner face of the body main so as to form a watertight volume and delimited by the first connecting wall, the second connecting wall, the bonding wall and the main body, one end of the second connecting wall fixed to the inner face of the main body having a thickness less than that of the upper wall of the main body, - the thickness of the end of the second connecting wall fixed to the inner face of the main body is between 10% and 15% of that of the upper wall of the main body, - the angle between the second connecting wall and the inner face of the main body is between 60° and 90°, and - the outer panel is made of a material chosen from polypropylene, polycarbonate, polyamide, acrylonitrile butadiene styrene or a mixture of polycarbonate and acrylonitrile butadiene styrene.

[0011] The invention also relates to a motor vehicle tailgate comprising: - an exterior panel according to the invention, - a lining, - a bead of adhesive placed between the outer panel and the lining so as to bond the outer panel and the lining together and to create a watertight inner volume between them, the bead of glue being arranged without discontinuity from the bonding wall to the inner face of the main body, being placed on the first bonding wall.

[0012] The invention also relates to a method for manufacturing an exterior tailgate panel of a motor vehicle according to the invention using a mold comprising a die, a punch and at least two movable blocks in the same direction and in opposite directions, the method comprising the following steps: - closing the mold, - injection of plastic material forming the outer panel, the first connecting wall being molded between the two movable wedges, - removal of the movable wedges by moving them in opposite directions, - opening of the mold and extraction of the outer panel. Brief description of the figures

[0013] The invention will be better understood upon reading the following description, given solely by way of example and made with reference to the accompanying drawings in which:

[0014] [Fig.4] is a first perspective view of a portion of an exterior tailgate panel according to the invention,

[0015] [Fig.5] is a perspective view from an angle of a portion of an exterior tailgate panel according to the invention,

[0016] [Fig.6] is a perspective view of a portion of an exterior tailgate panel according to the invention,

[0017] [Fig.7] is a first cross-sectional view of a portion of an exterior tailgate panel according to the invention,

[0018] [Fig.8] is a second cross-sectional view of a portion of an exterior tailgate panel according to the invention, and

[0019] [Fig.9] is a representation (in local section) of a mold of an exterior tailgate panel according to the invention. Detailed description

[0020] Reference is now made to Figures 4 to 6, which illustrate a portion of an exterior panel 20 of a motor vehicle tailgate (the tailgate may be similar to tailgate 2 in [Fig. 1]) intended to be bonded to a lining (not shown). Figures 4 to 6 illustrate one side of the exterior panel 20, which includes a housing for an optical unit. The same configuration, i.e., a portion of the exterior panel including a second housing for an optical unit, is installed on the other side of the exterior panel 20 (not shown in Figures 4 to 6, but this configuration is visible in [Fig. 1]). The exterior panel 20 is made of plastic. It may be made of a material selected from polypropylene, polycarbonate, polyamide, acrylonitrile butadiene styrene, or a mixture of polycarbonate and acrylonitrile butadiene styrene.

[0021] The outer panel 20 includes in the lower part of the tailgate a main body 22 comprising at least a lateral edge 24 (locally forming a boundary of a lateral wall 25) and an upper edge 26 (locally forming a boundary of an upper wall 27).

[0022] The outer panel 20 further includes on its outer face a recess 28 forming a housing for an optical block and comprising a bottom wall 30.

[0023] The outer panel 20 further comprises on its inner face a bonding wall 32 extending from the bottom wall 30 and along the side wall 25, more precisely along the side edge 24. This bonding wall 32 comprises a first side 34 connected to the side edge 24 of the side wall 25, and a terminal portion 36 connected to the upper edge 26 of the upper wall 27 of the main body 22, the bonding wall 32 forming a first bonding ramp for the outer panel 20 onto a lining. Indeed, as can be seen in Figures 4 and 5, a bead of adhesive 38 is deposited on the inner face of the outer panel 20, this bead of adhesive extending (not shown) peripherally along the edge of the outer panel 20 to form a bonding track. It is deposited, among other things, on the inner face of the bottom wall 30 and on the bonding wall 32 and finally on the upper edge 26. As explained above, the bonding wall 32 forms, on this first ramp, a transition slope, as explained for the prior art, between the bottom wall 30 of the recess 28 and the upper edge 26 of the upper wall 27 of the outer panel 20 allowing to ensure homogeneous bonding of the outer panel 20 with a lining.

[0024] The junction zone 37 between the bonding wall 32 and the upper edge 26 can be of a thickness between 50% and 75% of the thickness of the rest of the outer panel 20, in particular the thickness of the upper wall 27.

[0025] The outer panel 20 further comprises a first connecting wall 40 (particularly visible in Figures 5 and 6) extending from the terminal portion 36 of the bonding wall 32, and from a second side 42 of the bonding wall 32 opposite the first side 34 of the bonding wall 32 connected to the lateral edge 24, to an inner face of the upper wall 27 of the main body 22 so as to form a second bonding ramp of the outer panel 20 on a lining, an end 44 (visible in Figures 5 and 6) of the first connecting wall 40 connected to the inner face of the main body 22 having a thickness less than that of the upper face 27 of the outer panel 20.

[0026] The first connecting wall 40 thus makes it possible to create a junction between the bonding wall 32 and the inner face of the upper wall 27 of the outer panel 20 in order to ensure a continuous surface for depositing the adhesive bead 38. This surface comprises the bonding wall 32 extending from the bottom wall 30 to the upper edge 26 of the upper wall 27, and the first connecting wall 40 allowing the terminal portion 36 to be connected to the inner face of the upper wall 27 of the outer panel 20. The adhesive bead 38 is therefore deposited around the perimeter of the inner face of the outer panel 20, and thus on the bonding wall 32 up to the junction at the upper edge 26, and is deposited on the first connecting wall 40 and on the inner face of the outer panel 20 along the upper edge 26.When bonding the outer panel 20 with a lining, the assembly pressure between the outer panel 20 and the lining is locally supported at the junction between the end portion 36 and the upper edge 26.

[0027] The first bonding wall 40 allows for the continuous application of the adhesive bead 38, but the bond between the first bonding wall 40 and the inner face of the main body 22 is thinned so as not to generate a surface defect (shrinkage sagging) on ​​the outer face of the upper wall 27 of the main body 22. This thinning is permitted because the bonding forces are absorbed and distributed elsewhere. As we will see later, the bond between the first bonding wall 40 and the inner face of the upper wall of the main body 22 ensures a seal in the area where the first bonding wall 40 is formed.

[0028] Advantageously, the thickness of the end 44 of the first connecting wall 40 fixed to the inner face of the main body 22 is between 10% and 15% of that of the rest of the outer panel. For example, its thickness may be: - between 0.3 and 0.45 millimeters for an outer panel 20 with a thickness approximately equal to 3 millimeters, or - between 0.32 and 0.48 millimeters for an exterior panel 20 with a thickness approximately equal to 3.2 millimeters.

[0029] The thickness ratio described above makes it possible both to avoid the appearance of defects (as explained above) and very little, or even no risk of breakage of the end 44 of the first connecting wall 40 at the time of bonding (the assembly force being proportional to the surface subjected to pressure, it is taken up as explained previously by the junction between the terminal portion 36 of the bonding wall 30 and the upper edge 26).

[0030] Advantageously, the angle between the first connecting wall 40 and the external face of the main body 22 is between 60° and 90°. Such an angle makes it possible to increase the resistance of the end 44 of the connecting wall 40 because it promotes, during bonding, stressing by compression phenomena rather than by bending phenomena.

[0031] The outer panel 20 may further comprise a second connecting wall 46 (visible in Figures 5 to 8) connected to the first connecting wall 40, the bonding wall 32, the side wall 25, and the inner face of the main body 22 so as to form a watertight volume 41 (referenced in [Fig. 7]) delimited by the first connecting wall 40, the second connecting wall 46, the bonding wall 32, and the main body 22. Indeed, as can be seen in [Fig. 9], which illustrates a mold of the outer panel 20, the first connecting wall 40 is molded by means of movable parts (or movable blocks) of the mold in order to allow demolding of the molded outer panel 20. This leads to the appearance of a discontinuity in the side wall 25 of the outer panel 20 (resulting from the removal of a movable element of the mold).To prevent any water from entering the tailgate through this discontinuity, the volume 41 left free by the removal of the moving element is watertight and delimited by the first connecting wall 40, the second connecting wall 46, the bonding wall 30 and the main body 22.

[0032] One end 48 of the second connecting wall 46, which is connected to the inner face of the upper wall 27 of the main body 22, may have a thickness less than that of the upper wall of the main body 22. The thickness ratio may be the same as for the end 44 of the first connecting wall 40 (thickness between 10% and 15% of that of the rest of the upper wall 27). This reduction in thickness makes it possible to obtain the same effects as for the first connecting wall 40 (absence of defects). (appearance on the external face of the main body 22, no risk of breakage of this end during gluing).

[0033] As with the first connecting wall 40, the angle between the second connecting wall 46 and the external face of the main body 22 is between 60° and 90°. As with the first connecting wall 40, such an angle increases the strength of the end 48 of the second connecting wall 46 because, during bonding, it promotes stress through compression rather than bending.

[0034] The invention also relates to a motor vehicle tailgate comprising: - the outer panel 20 according to the invention, - a lining, - the bead of glue 38 arranged between the outer panel 20 and the lining so as to bond the outer panel 20 and the lining together and to create a watertight inner volume between the outer panel and the lining, the glue bead 38 being disposed without discontinuity from the bonding wall 32 to the inner face of the main body 22 by being disposed on the first bonding wall 40.

[0035] The invention also relates to a method for manufacturing an exterior tailgate panel 20 of a motor vehicle according to the invention using a mold comprising a die 50, a punch 52, and at least two shims 54 and 56 movable in the same direction and in opposite directions. The method comprises the following steps: - Mold closure. [Fig.9] illustrates a "mold closed" position of the movable blocks 54 and 56, the die 50 and the punch 52. This closed position allows several zones to be defined: a first zone 58 allowing the molding of the bonding wall 32, a second zone 60 allowing the molding of the first connecting wall 40 and a third zone 62 allowing the molding of the second connecting wall 46. - Injection of plastic material forming the outer panel 2. The first connecting wall 40 is molded between the two movable wedges 54 and 56, as is the second connecting wall 46. - Removal of the movable wedges 54 and 56 by moving them in opposite directions 64 and 66. This removal in two opposite directions allows the molded outer panel 20 to be freed and extracted from the mold. The removal of the movable wedge 54 leads to the appearance of the discontinuity in the side wall of the outer panel 20 described above, necessitating the creation of a watertight volume 41 to prevent any water from entering the tailgate. - Opening of the mold and extraction of the outer panel 20.

[0036] The invention is not limited to the embodiments presented and other embodiments will be obvious to a person skilled in the art. List of references

[0037] 2: tailgate 4: lining 6, 20: exterior panel

[0038] 8, 38: glue bead

[0039] 10, 32: bonding wall

[0040] 11, 11': ends of the outer panel

[0041] 12, 25: side wall

[0042] 13: upper end of the bonding wall

[0043] 14, 14', 30: bottom wall

[0044] 15: inner face of the bottom wall

[0045] 16, 28: recess

[0046] 17: inner face of the upper wall

[0047] 18, 27: upper wall

[0048] 19: external face of the upper wall 18

[0049] 22: main body

[0050] 24: lateral edge

[0051] 26: upper edge

[0052] 10', 34: first side of the bonding wall

[0053] 36: terminal portion of the bonding wall

[0054] 37: junction zone

[0055] 40: first connecting wall

[0056] 41: volume

[0057] 10”, 42: second side of the bonding wall

[0058] 44: end of the first connecting wall

[0059] 46: second connecting wall

[0060] 48: end of the second connecting wall

[0061] 50: matrix

[0062] 52: punch

[0063] 54, 56: movable wedges

[0064] 58: first zone

[0065] 60: second zone

[0066] 62: third zone

[0067] 64, 66: directions for removing the movable wedges

Claims

Demands

1. Exterior panel (20) of a motor vehicle tailgate intended to be bonded to a lining, the exterior panel (20) being made of plastic material and comprising: - a main body (22) comprising at least one side wall (24) and one top wall (27), - a recess (28) forming a housing for a light unit and comprising a bottom wall (30), and - a bonding wall (32) extending from the bottom wall (30) and along the side wall (24), comprising a first side (34) connected to the side wall (24), and comprising a terminal portion (36) connected to a top edge (26) of the top wall (27), the bonding wall (32) forming a first bonding ramp of the exterior panel (20) to a lining, - a first connecting wall (40) extending at the level of the terminal portion (36) of the bonding wall (32),from a second side (42) of the bonding wall (32) opposite the first side (34) of the bonding wall (32) connected to the side wall (24), to an inner face of the main body (22) so as to form a second bonding ramp of the outer panel (20) onto a lining, one end (44) of the first connecting wall (40) fixed to the inner face of the main body (22) having a thickness less than that of the upper wall (27) of the main body (22).

2. Outer panel (20) according to claim 1, wherein the thickness of the end (44) of the first connecting wall (40) fixed to the inner face of the main body (22) is between 10% and 15% of that of the upper wall (27) of the main body (22).

3. Outer panel (20) according to any one of the preceding claims, wherein the angle between the first connecting wall (40) and an external face of the main body (22) is between 60° and 90°.

4. An outer panel (20) according to any one of the preceding claims, comprising a second connecting wall (46) connected to the first connecting wall (40), to the bonding wall (32) and to the inner face of the main body (22) so as to form a volume (41) watertight and delimited by the first connecting wall (40), the second connecting wall (46), the bonding wall (32) and the main body (22), one end (48) of the second connecting wall (46) fixed to the inner face of the main body (22) having a thickness less than that of the upper wall (27) of the main body (22).

5. Outer panel (20) according to the preceding claim, wherein the thickness of the end (48) of the second connecting wall (46) fixed to the inner face of the main body (22) is between 10% and 15% of that of the upper wall (27) of the main body (22).

6. Outer panel (20) according to any one of claims 4 or 5, wherein the angle between the second connecting wall (46) and the inner face of the main body (22) is between 60° and 90°.

7. Outer panel (20) according to any one of the preceding claims, the outer panel (20) being made of a material selected from polypropylene, polycarbonate, polyamide, acrylonitrile butadiene styrene or a mixture of polycarbonate and acrylonitrile butadiene styrene.

8. Motor vehicle tailgate comprising: - an outer panel (20) according to any one of the preceding claims, - a lining, - a bead of glue (38) disposed between the outer panel (20) and the lining so as to join by gluing the outer panel (20) and the lining and to create between them a watertight inner volume, the bead of glue (38) being disposed without discontinuity from the bonding wall (32) to the inner face of the main body (22) by being disposed on the first bonding wall (40).

9. A method for manufacturing an outer panel (20) of a motor vehicle tailgate according to any one of claims 1 to 7 using a mold comprising a die (50), a punch (52) and at least two wedges (54, 56) movable in the same direction and in opposite directions, the method comprising the following steps: - closing the mold, - injecting plastic material forming the outer panel (20), the first connecting wall (40) being molded between the two movable wedges (54, 56), removal of the movable wedges (54, 56) by displacement in opposite directions, opening of the mold and extraction of the outer panel (20).

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