VEHICLE TAILGATE

Abstract

The invention relates to a vehicle tailgate made of a plastic material (12), comprising an inner panel (1), an outer panel (2) and a first glue bead (31) applied between the inner panel (1) and the outer panel (2) so as to assemble the two panels by gluing and to create a water-tight inner space between the two panels, the outer panel (2) having a skin (21) with an appearance surface, a housing (14) for receiving an optical unit, which is delimited by a peripheral wall (22) joined to the skin (21), and a cavity (25) delimited by the skin (21), at least a portion of the peripheral wall (22) of the housing (14) and walls (23, 26) projecting from the housing (14) towards the inner face of the skin (21). The invention is characterised in that at least one wall of the walls (23, 26) projecting from the housing (14) towards the inner face of the skin (21) and participating in delimiting the cavity (25) does not touch the inner face of the skin (21), such that there is a gap (27) between the at least one wall and the inner face of the skin (21), and in that a second glue bead (32) is applied at the gap (27) in order to seal the gap and thus ensure that the cavity (25) is water-tight. The invention further relates to a method for manufacturing a vehicle tailgate of this type.

Claims

1. Vehicle tailgate (12) made of a plastic material, comprising an inner panel (1), an outer panel (2) and a first glue bead (31) applied between the inner panel (1) and the outer panel (2) so as to assemble by gluing the two panels and to create a water-tight inner space between the two panels, the outer panel (2) having: a skin (21) with an appearance surface; a housing (14) for receiving an optical unit, which is delimited by a peripheral wall (22) joined to the skin (21), and a cavity (25) delimited at a time by the skin (21), at least a portion of the peripheral wall (22) of the housing (14), and walls (23, 26) projecting from the housing (14) towards an inner face of the skin (21), characterised in that at least one wall of the walls (23, 26) projecting from the housing (14) towards the inner face of the skin (21) which participate in delimiting the cavity (25) does not touch the inner face of the skin (21), such that there is a gap (27) between said at least one wall and the inner face of the skin (21), and in that a second glue bead (32) is applied at the gap (27) in order to seal the gap and thus ensure that the cavity (25) is water-tight.

2. Vehicle tailgate according to claim 1, wherein the walls (23, 26) projecting from the housing (14) towards the inner face of the skin (21) and participating in delimiting the cavity (25) comprise a bridge wall (23) and a lateral wall (26), the bridge wall (23) covering an angle formed by the housing (14) and the inner face of the skin (21) and the lateral wall (26) closing the cavity (25) on one side of the cavity (25).

3. Vehicle tailgate according to claim 2, wherein the lateral wall (26) is located on a lateral face of the tailgate (12) when a movable slider moves, during moulding of the cavity (25), along the Y axis towards the median plane of the vehicle, or is located on a side of the cavity (25) opposite the lateral face of the tailgate (12) when the movable slider moves, during moulding of the cavity (25), along the Y axis towards the two lateral planes of the vehicle.

4. Vehicle tailgate according to any one of claims 1 to 3, wherein the gap (27) is located behind or near a style line (13) which is visible on the appearance surface of the skin (21).

5. Vehicle tailgate according to any one of claims 1 to 3, wherein the first glue bead (31) and the second glue bead (32) are applied in such a way that they overlap and cross each other, and their up and down overlap order can be interchanged.

6. Vehicle tailgate according to any one of claims 1 to 3, wherein the first glue bead (31) is applied on the inner face of the outer panel (2) and forms a continuous sealing binding.

7. Vehicle tailgate according to any one of claims 1 to 3, wherein the first glue bead (31) and the second glue bead (32) are formed of water-tight glue applied by a robot.

8. Vehicle tailgate according to any one of claims 1 to 3, wherein a thickness of a free end of said at least one wall which does not touch the inner face of the skin (21) is reduced to facilitate passage of the second glue bead (32) under the free end, in order to ensure that on both sides of said at least one wall is water-tight.

9. Vehicle tailgate according to any one of claims 1 to 3, wherein a free end of said at least one wall which does not touch the inner face of the skin (21) forms a groove for receiving the second glue bead (32).

10. Method for manufacturing a vehicle tailgate according to any one of claims 1 to 9, wherein a movable slider is used in a mould to manufacture the cavity (25) during moulding of the outer panel (2), and the tailgate (12) is formed by assembling by gluing the outer panel (2) with the inner panel (1), by means of the following main steps: applying glue on the inner face of the outer panel (2) to form the first glue bead (31); applying the glue along the gap (27) to form the second glue bead (32); pressing, in a main direction of assembly of the tailgate (12), with a suitable pressure, the outer panel (2) and the inner panel (1), to assemble them by gluing.

Description

[0015] The attached figures schematically illustrate preferred but not limiting embodiments of the invention which are given solely by way of example. The invention will be better understood and its advantages and features will become clearly apparent on reading the description below and referring to the attached figures. Note that the directions, shapes, angles, dimensions (including lengths and thicknesses), distances and proportions illustrated on the attached figures are given for indication only and are not limiting in any way the invention. Amongst these figures:

[0016] FIG. 1 is a general schematic view of a tailgate seen from the rear of a vehicle, in which the directions X, Y and Z of the vehicle are illustrated indicatively;

[0017] FIG. 2 is a three-dimensional schematic exploded view of the partial area of a rear light surrounded by a circle in FIG. 1;

[0018] FIG. 3 is a three-dimensional schematic view of the inner panel of FIG. 2;

[0019] FIG. 4 is a three-dimensional schematic view of the inner panel of FIG. 3 to which the first glue bead is applied;

[0020] FIG. 5 is a three-dimensional schematic view of the outer panel of FIG. 2;

[0021] FIG. 6 is a three-dimensional schematic view from another angle of the outer panel of FIG. 5;

[0022] FIG. 7 is a three-dimensional schematic view from yet another angle of the outer panel of FIG. 5;

[0023] FIG. 8 is a three-dimensional schematic view of the inner face of the outer panel of FIG. 7 to which the first glue bead is applied;

[0024] FIG. 9 is a three-dimensional schematic view of the inner face of the outer panel of FIG. 8 to which the second glue bead is applied.

[0025] Preferred embodiments of a tailgate according to the invention are described below, referring to the attached figures in which the identical numerical references are used to designate similar elements having similar functions.

[0026] FIG. 1 is a general schematic view of a tailgate 12 seen from the rear of a vehicle, in which a portion of the outer panel 2 of the tailgate 12 is removed in order to reveal the inner panel 1 opposite this part, and the directions X, Y and Z of the vehicle are illustrated indicatively. This tailgate is designed to include housings 14 intended to receive optical units (rear lights). In this embodiment, the rear lights are for example arranged symmetrically on the two lateral edges of the tailgate. Since the appearance style of the vehicles varies considerably, the shape of the housings 14 located on the tailgate may also vary considerably. This shape may for example be very deep and have abrupt walls which form substantially right or even acute angles with the appearance surface of the tailgate (visible from outside of the vehicle) or with the bottom of the housings.

[0027] As shown on FIG. 2 which is an exploded view of the partial area of a rear light shown on FIG. 1, the tailgate 12 comprises an inner panel 1 and an outer panel 2. Generally, the inner panel 1 is a structural part of the vehicle, which is also called a lining, while the outer panel 2 is an appearance part. For example, the inner panel 1 is a tailgate frame made of a thermoplastic (such as polypropylenePP) or thermosetting plastic material which is preferably SMC (Sheet Moulding Compound); the outer panel 2 is the appearance skin of the tailgate which is made of a thermoplastic material, for example polypropylene. The inner and outer panels often have complex three-dimensional shapes which are obviously not limited to the shapes illustrated indicatively on the attached figures.

[0028] As shown on FIGS. 2 and 5 to 9, the outer panel 2 comprises a skin 21 forming the appearance surface and at least one housing 14 for receiving an optical unit. As shown on FIG. 5, the housing 14 is delimited by a peripheral wall 22 joined to the skin 21. As shown on FIGS. 2, 5 and 6, the outer panel 2 comprises a cavity 25 delimited at a time by the skin 21, the peripheral wall 22 of the housing 14 and the walls projecting from the housing 14 towards the inner face of the skin 21. The walls which project from the housing 14 towards the inner face of the skin 21 and which participate in delimiting the cavity 25 comprise a bridge wall 23 and a lateral wall 26. The bridge wall 23 is for example illustrated on FIGS. 6 and 7 and the lateral wall 26 is for example illustrated on FIG. 7. In this embodiment, the bridge wall 23 and the lateral wall 26 do not come into contact with the inner face of the skin 21, so that there is a gap 27 present between the end (the bottom) of the bridge wall 23 and the inner face of the skin 21, and between the end (the bottom) of the lateral wall 26 and the inner face of the skin 21. It is understood that the gap 27 is not limited to what is illustrated on the figures and it is for example possible that there is a gap 27 only between the bridge wall 23 and the inner face of the skin 21.

[0029] As shown on FIG. 7, the lateral wall 26 closes the cavity 25 on one side of the cavity 25. In the example shown on FIG. 7, the lateral wall 26 is located on a side of the cavity opposite the lateral face of the tailgate 12 (this side is closer to the median plane Y.sub.0), which means that during the moulding of the cavity 25, the movable slider moves along the Y axis towards the two lateral planes Y.sub.lat of the vehicle. Those skilled in the art will understand (see below) that alternatively, in the case where during the moulding of the cavity, the movable slider moves along the Y axis towards the median plane Y.sub.0 of the vehicle, the lateral wall 26 is located on a lateral face of the tailgate 12. In particular, when the lateral wall 26 is located on a lateral face of the tailgate 12, since the lateral wall 26 itself is a part of the skin of this lateral face, there is no gap between this lateral wall 26 and the inner face of the skin 21, and the lateral wall 26 is visible when the tailgate 12 is raised.

[0030] In addition, note that amongst the skin 21 of the outer panel 2, the peripheral wall 22 and the bridge wall 23, only the skin 21 is visible from outside of the vehicle when the optical units (for example the rear lights) are well installed in position in the housings 14.

[0031] Usually, the inner panel 1 and the outer panel 2 are assembled by gluing with the glue bead 31 which is called the first glue bead, and this glue bead 31 is advantageously used to seal the inner space between the inner and outer panels such that this inner space remains dry. This protects the electrical wires and equipment located in the tailgate and between the inner and outer panels against humidity. A robot can be used to apply the glue on the inner face of the outer panel 2 in order to form the glue bead 31, as shown on FIG. 8. Obviously, the glue bead 31 can also be applied on the face of the inner panel 1 which is intended to be glued to the outer panel 2, as shown on FIG. 4. Then, the outer panel 2 and the inner panel 1 are bonded together and a continuous sealing binding is obtained by pressing the inner and outer panels together with a suitable pressure in the main direction of assembly of the tailgate 12. Preferably, this sealing path itself forms a closed circuit. Since the bridge wall 23 is used to cover the angle (the corner) formed by the housing 14 and the inner face of the skin 21 (as shown on FIG. 6), the glue bead 31 avoids this angle and passes by the bridge wall 23 (as shown on FIG. 8), which allows therefore to improve the abrupt degree of the gluing path, in order to facilitate the access of the adhesive applicator of the robot and thus the compression of the inner and outer panels to bond them together.

[0032] Apart from the conventional glue bead 31, the tailgate according to the invention conceives of using an additional glue bead 32 at the gap 27 to seal the gap 27 to ensure that the cavity 25 is water-tight, as shown on FIG. 9. This additional glue bead 32 can be qualified as second glue bead, and thus the conventional glue bead 31 can be qualified as first glue bead. The first glue bead 31 and the second glue bead 32 are preferably applied in such a way that they overlap and cross each other, and their up and down overlap order may be interchanged.

[0033] In particular, in the tailgate according to this invention, since the visual defects such as sink marks or flow lines are attenuated at their source, by reducing the junctions between the inner face of the skin 21 and the walls 23, 26 which project from the housing 14 towards the inner face of the skin 21 and which participate in delimiting the cavity 25, it is possible that a thickness of a free end (i.e. a suspended end due to the presence of the gap 27) of the wall (or the walls) amongst these walls which does not (or do not) touch the inner face of the skin 21 is not reduced. However, it is preferred that this thickness is reduced. For example, FIG. 6 shows that the thickness of the free end of the outer face of the bridge wall 23 is reduced. This reduced thickness favours the passage of the second glue bead 32 under this free end in order to ensure that both sides of the bridge wall 23 are water-tight. Alternatively, the wall (or walls) amongst the walls which does not (or do not) touch the inner face of the skin 21 forms (or form) a groove for receiving the second glue bead 32.

[0034] According to an embodiment of the invention, the gap 27 is located behind or near a style line 13 which can be seen on the appearance surface of the skin 21. This allows to mask and attenuate the visual defects which, even if they are reduced, may nevertheless be generated. As shown on FIG. 1, this style line 13 often corresponds to a fold of the skin 21 of the outer panel 2 and this fold forms a square or a visually interrupted line on the appearance surface of the tailgate 12.

[0035] A method for manufacturing a tailgate according to an embodiment of this invention is described below. According to this method, when moulding the outer panel 2 of the tailgate 12, a movable slider is used in a mould to manufacture the cavity 25 delimited by the skin 21, the peripheral wall 22, the bridge wall 23 and the lateral wall 26. This allows thus to mould the cavity 25, even if it is no longer possible to demould the cavity 25 naturally since it is covered by the bridge wall 23. For moulding of injection type, this movable slider is a retractable core. The movable slider can be easily removed from another non-closed side of the cavity 25, this non-closed side being opposite the side closed by the lateral wall 26 according to an embodiment of this invention.

[0036] Similarly, according to the method, the main steps for assembling by gluing the outer panel 2 with the inner panel 1 to form the tailgate 12 are as follows:

[0037] applying glue with a robot on the inner face of the outer panel 2, the glue applicator of the robot being able to access the various positions of the inner face very easily and move smoothly along this inner face because the abrupt angle of the inner face is reduced by means of the bridge wall 23;

[0038] making the glue applicator of robot move on the inner face of the outer panel 2 in order to form a continuous gluing binding intended to glue the inner panel 1, then making the glue applicator of the robot move along the gap 27 which is located between on the one hand, the bridge wall 23 or the lateral wall 26, and on the other hand, the inner face of the skin 21, to apply an additional glue bead intended to seal the cavity 25 at the gap 27;

[0039] then, pressing, in the main direction of assembly of the tailgate, with a suitable pressure, the outer panel 2 and the inner panel 1, to assemble the two panels by gluing, such that the glue is compressed uniformly (spread and equalised) on the positions where it is applied to form the first glue bead 31 and the second glue bead 32 which are deposited on top of each other (i.e. they overlap) and cross each other, in order to ensure the water-tightness between the inner and outer panels as well as at the gap 27.

[0040] This invention is described above using a limited number of embodiments. However, those skilled in the art will understand that, if no prejudice is brought to the principles of this invention, modifications even major modifications can be made to the embodiments described and to their details, without departing from the scope of this invention which is only defined by the attached claims.