WO2005065974A1

WO2005065974A1 - Vehicle body part, such as a tailgate comprising slats

Info

Publication number: WO2005065974A1
Application number: PCT/FR2004/003171
Authority: WO
Inventors: Frédéric Charnoz; Emilie Bouchez; Thierry Renault; Denis Lebugle
Original assignee: Cadence Innovation
Priority date: 2003-12-10
Filing date: 2004-12-09
Publication date: 2005-07-21
Also published as: FR2863515B1; EP1697154A1; FR2863515A1

Abstract

The invention relates to part (6) for a vehicle, such as a tailgate, comprising a body. The inventive part also comprises a metal layer (12) which can be seen from the exterior side of the part.

Description

BODY PIECE FOR VEHICLE, PARTICULARLY TAILGATE COMPRISING SLATS

The invention relates to bodywork parts and in particular louvered tailgates for a motor vehicle. Such tailgates are already known from the prior art, in particular from application EP-1 270 297 which discloses a tailgate made of plastic. These tailgates have many advantages, in particular due to their reduced size in the open position. However, consumer surveys show that such tailgates affect the overall appearance of the vehicle. An object of the invention is to facilitate the integration of bodywork parts and in particular of this type of tailgate in the aesthetics of the vehicle. To this end, there is provided according to the invention a vehicle body part, in particular a tailgate, comprising a body and further a metallic layer visible from an external side of the part. Thus, the metal layer gives the part an appearance close to that of the vehicle body, or even identical to the latter. The integration of the part into the aesthetics of the vehicle is therefore greatly improved. The part according to the invention may also have at least any one of the following characteristics:

- the metal layer comprises a sheet;

- the body comprises a plastic material; - the body comprises reinforcing fibers;

- The body comprises a layer of cellular structure; According to the invention, there is also provided a tailgate for a vehicle comprising strips each comprising a body, at least one of the strips further comprising a metallic layer visible from an external side of the tailgate. Advantageously, at least two of the strips are in one piece with one another. Advantageously, it comprises two longitudinal edges extending in the extension of two respective ends of the strips, being distinct from these ends. According to the invention, there is also provided a method of manufacturing a part for a vehicle, in which a body layer and a metal layer are stacked in a forming mold so that the metal layer is visible from an external side of the part. . The method according to the invention may also have at least any one of the following characteristics:

- Prior to stacking, the body layer is heated, in particular to a temperature between 150 and 250 ° C;

- prior to stacking, the metal layer is shaped; - The metal layer is shaped on a matrix then constituting a part of the mold for forming the stack;

- The mold is heated, in particular to a temperature between 50 and 100 ° C;

- the metal layer is glued to the body layer; - The stack is crushed locally, in particular the body layer, in the forming mold to form at least one hinge, the crushing giving in particular the crushed parts a thickness of less than 20% of the thickness of non-crushed parts of the room ;

- the part is cut from the forming mold; and - a joint is overmolded on the part in the forming mold. Other characteristics and advantages of the invention will become apparent in the following description of a preferred embodiment given by way of nonlimiting example with reference to the appended drawings in which:

- Figure 1 is a perspective view of the rear part of a vehicle provided with a tailgate according to the invention; - Figure 2 is a perspective view of the tailgate of Figure 1 in the closed position;

- Figures 3 and 4 are two sectional views along a median longitudinal vertical plane of the vehicle showing the tailgate of Figure 1 respectively in the open position and in the closed position;

- Figure 5 is a flowchart illustrating the manufacturing process of the tailgate of Figure 1;

- Figure 6 is a schematic view of the tailgate forming mold; and

- Figure 7 is a schematic view of a layer of the tailgate. In the present example, the bodywork part according to the invention is a tailgate with descending lamellae, that is to say opening upwards. It could alternatively be another type of bodywork part, for example a side panel, a drop side, a roof panel which may be retractable, or a tailgate opening downwards. FIG. 1 illustrates a vehicle 2, in this case of the commercial vehicle type, having on its rear face an opening 4 for loading goods into the rear part of the vehicle. This opening 4 is closed by a tailgate 6 according to the invention. Referring to Figure 2, the tailgate has a succession of blades 8 very precisely the number of 12 in this example, this number is not limiting. Each strip has an essentially flat and rectangular shape when viewed from the front. The edges of the strips extend in coincidence with each other. The slats all have the same length measured in the horizontal transverse direction of the vehicle. However, not all of the slats have the same height h. In the present example, the slats are divided into two groups. The lamellae of the first group 9 in number have a height equal to each other and greater than the lamellae of the second group which are 3 in number and therefore have a height less than the latter. The 3 strips of the second group occupy positions 2, 3 and 4 starting from the highest strip in the closed position as in Figure 2. The tailgate 6 is in one piece. It comprises a body layer 10 forming a body of each strip, as well as a metal layer 12 in this case formed by a sheet. The layer 12 is visible from an external side of the tailgate as shown in FIG. 2. The body layer 10 comprises, as illustrated in FIG. 7, two plastic walls 11 reinforced with glass fibers as well as a layer of honeycomb structure 13 extending between these two walls. The honeycomb structure will be an expanded foam or a honeycomb structure for example. The plastic in this case is polypropylene. The tailgate 6 comprises for each pair of consecutive slats 8 a hinge 15 formed by a film in one piece with the slats. The tailgate comprises two longitudinal edges 16 extending in the extension of two respective ends of the slats, being distinct from these ends. As seen in Figure 2, each edge 16 is smooth and without relief and has a thickness less than a thickness of the lamellae. As illustrated in FIG. 3, this rear hatch of hybrid structure can be retracted under the roof of the vehicle to make the interior of the vehicle accessible through the opening 4. The principle is similar to that of a rolling shutter. Its opening may, depending on the case, be controlled by a motor or manual. The tailgate is guided during its movement by means of slides in which the respective edges slide 16. The deformation of the tailgate during this movement is permitted by the hinges. The advantage of such a tailgate is that it does not require space behind the vehicle for opening, as hinged doors would. Such a tailgate protects the interior of the vehicle against water, gas, theft, as well as acoustically. Opening and closing can be quick, taking no more than 5-10 seconds. It is robust, resists indentation as well as small impacts. Thanks to the fact that the slats are in one piece with each other, the function watertightness is ensured unlike the case of a tailgate made up of individual slats. The sheet is here a steel sheet designed so that it can deform during the opening and closing of the door while remaining in its elastic range. Its thickness is here comprised in 0.25 mm and 0.60 mm. The sheet used is prepainted or prepainted on the visible side 14 constituting the external face of the tailgate. The tailgate thus has an appearance similar to that of the vehicle body parts. We will now describe an example of implementation of the method according to the invention for manufacturing the tailgate 6. For manufacturing, the sheet 12 is covered with a layer of adhesive on its reverse side 16 as illustrated in Figure 6. This adhesive can in this case be activated hot at 180 ° C. We can for example use for this purpose the pre-glued sheet called "solbond" distributed by the company Arcelor. The sheet is the subject of a first series of process steps as illustrated in Figure 5. Originally brought to step 17 in the form of a sidewall or from a coil, the sheet is stamped to shape it. This stamping 18 takes place between a die 20 and a punch not illustrated. In a subsequent step 22, the sheet 12 is transferred with the die 20 under the forming press which will be used to shape the tailgate itself. The die 20 and the press 36 constitute the mold for forming the tailgate. The non-glued face 14 of the sheet 12 is in contact with the die 20. Alternatively, it could be provided that the stamping takes place in a tool independent of the forming mold which will be used for the shaping of the tailgate itself. Independently of this first series of steps, a second series of steps is carried out concerning the body layer 10. In the present example, it is made of a material called “sandwiform” distributed by the company Venture Industries. This material is here formed by a polypropylene core 13 with a structure of nests of bees on either side of which are arranged layers 11 of plastic material reinforced with glass fibers. It may also be polypropylene. The walls are for example formed in the Twintex product distributed by the company Saint Gobain Vetrotex. The walls may alternatively be formed from polypropylene reinforced with glass fiber mats. The core will have a thickness between 10 and 20 mm. The three layers constituting the body layer 10 are preassembled in step 30 in a manner known per se in a heated mold. The product thus formed is heated in step 32 in an oven to be brought to a temperature between 150 and 250 ° C and in this case 200 ° C. Once brought to temperature, the layer 10 is transferred in step 34 to the forming mold 20, 36 illustrated in FIG. 6. The sheet 12 is stacked in this mold with its painted or varnished face 14 in contact with the matrix 20 and above the sheet the layer 10. The punch 36 of the mold is placed above the layer 10. The mold is shaped so as to effect, when it is closed, the shaping of the tailgate. Knowing that the adhesive of the sheet 12 is active at a temperature of 180 ° C. and that the sheet is in contact with the heated layer 10, closing the mold causes the sheet to stick to the layer 10. variant of preheating the sheet before adding it to the stack in order to activate the adhesive). During forming, the mold is heated to a temperature between 50 and 100 ° C, and in this case equal to 80 ° C. During this step, the shape of the sheet supported by the shape of the matrix 20 causes in cooperation with the piston or press 36 the local crushing of the body layer 10 so as to crush the cellular core by making the hinges 15 Thus, at the hinges, the body layer 10 has its thickness reduced by approximately 90% by comparison with the thickness of the non-crushed parts of this layer. Integrated sandwich hinges 15 in the form of a film are therefore produced by local compression of the sandwich. These hinges are strong enough to withstand a large number of opening and closing cycles, up to 130,000 cycles for one application utility. The mold is implemented at a pressure between 10 and 20.10 ⁶ Pa. The tailgate thus produced has great rigidity for a relatively low weight. The invention makes it possible with this press stroke to produce a part made up of lamellae linked together and therefore watertight. The manufacturing process is particularly simple in comparison with that involving the assembly of individually manufactured strips. Provision may be made for the tailgate 6 to be cut at the periphery to delimit the edges 16 when the mold is closed. In the same step, provision may be made for a gasket 19 to be molded onto the periphery of the tailgate as partially illustrated in FIG. 2. The sheet gives the tailgate the appearance of a bodywork part. In addition, no appearance defect related to the cells of the honeycomb in the sandwich appears on the sheet. The aforementioned tailgate is for example a curtain such as a rear curtain. Of course, many modifications can be made to the invention without departing from the scope thereof. We can plan to shape the sandwich from step 30 before its introduction into the mold for assembly with the sheet under a pressure of 5 to 10.10 ⁶ Pa. The mold pressures used in the context of the invention may more generally be between 1 and 30.10 ⁶ Pa. Provision may be made to give the sheet larger dimensions than the other parts of the part in order to be able to fold the edges of the sheet once the part is finished to give it better aspect. The sheet may be made of a metal other than steel, for example aluminum. Provision may be made for the tailgate to extend to the rear of the vehicle or to the side of the vehicle. We can constitute the sandwich (that is to say, assemble its different layers) during the operation of forming the part with the sheet. Thus, the stack of layers of the sandwich (not assembled) and the sheet will be placed in the mold. Closing the mold will constitute the sandwich at the same time as it will form the part. We can modify the number of layers of sandwich 10 and for example limit it to two. In the latter case, the sandwich 10 will consist of a single layer 11 and the core 13. The latter will then be for example directly in contact with the sheet and sandwiched between the layer 11 and the sheet. The invention is not limited to exterior body parts or even to body parts. Thus, it can be implemented for interior parts such as a load stop wall (for example in a utility vehicle) or a floor or even for a roof.

Claims

1. Vehicle body part (6), in particular tailgate, comprising a body, characterized in that it further comprises a metal layer (12) visible from an external side of the part.

2. Part according to the preceding claim, characterized in that the metal layer (12) comprises a sheet.

3. Part according to any one of the preceding claims, characterized in that the body (10) comprises a plastic material.

4. Part according to any one of the preceding claims, characterized in that the body (10) comprises reinforcing fibers.

5. Part according to any one of the preceding claims, characterized in that the body (10) comprises a layer of cellular structure.

6. Tailgate (6) for a vehicle comprising strips (8) each comprising a body, characterized in that at least one of the strips further comprises a metal layer (12) visible from an external side of the tailgate.

7. Tailgate according to the preceding claim, characterized in that at least two of the strips (8) are in one piece with one another.

8. Tailgate according to any one of claims 6 or 7, characterized in that it comprises two longitudinal edges (16) extending in the extension of two respective ends of the strips (8) being distinct from these ends.

9. A method of manufacturing a bodywork part (6) for a vehicle, characterized in that a body layer (10) and a metal layer (12) are stacked in a forming mold (20, 36) so the metal layer is visible from an external side of the part.

10. Method according to the preceding claim, characterized in that, prior to stacking, the body layer (10) is heated, in particular to a temperature between 150 and 250 ° C.

11. Method according to any one of claims 9 to 10, characterized in that, prior to stacking, the metal layer (12) is shaped.

12. Method according to the preceding claim, characterized in that the metal layer (12) is shaped on a matrix (20) then constituting a part of the mold for forming the stack.

13. Method according to any one of claims 9 to 12, characterized in that the mold is heated, in particular to a temperature between 50 and 100 ° C.

14. Method according to any one of claims 9 to 13, characterized in that the metal layer (12) is bonded to the body layer (10).

15. Method according to any one of claims 9 to 14, characterized in that the stack is locally crushed, in particular the body layer (10), in the forming mold to form at least one hinge (15), the crushing giving in particular to the crushed parts (15) a thickness less than 20% of the thickness of non-crushed parts (8) of the part.

16. Method according to any one of claims 9 to 15, characterized in that the part is cut from the forming mold.

17. Method according to any one of claims 9 to 16, characterized in that a seal (19) is overmolded on the part in the forming mold.