WO2006008399A1

WO2006008399A1 - Method for the production of a vehicle part between a stamping die and a bottom die and mold

Info

Publication number: WO2006008399A1
Application number: PCT/FR2005/001584
Authority: WO
Inventors: Thierry Renault; Jacques Heinry
Original assignee: Peguform France
Priority date: 2004-06-23
Filing date: 2005-06-23
Publication date: 2006-01-26
Also published as: FR2872083A1

Abstract

The invention relates to a method for the manufacture of a part, wherein at least two layers of material (34) are placed in a mold with a support (8) arranged between the two layers; and one part of the mold (4) is displaced in order to select one of the layers at a junction point between said part and the support.

Description

METHOD FOR MANUFACTURING A VEHICLE PART BETWEEN A PUNCH AND A MATRIX AND MOLD

The invention relates to the manufacture by molding of motor vehicle parts made of composite materials.

It is known from EP-794 051 in the name of the applicant a method in which a composite piece is manufactured by placing in a mold a honeycomb core and two skins on either side of it. Closing the mold causes the workpiece to be shaped. In addition, this closure leads to sectioning the material parts surrounding the workpiece and not intended to be part of it.

However, such a method has the disadvantage that the workpiece edge thus produced, although it is of very small size, is not always aesthetically satisfactory.

Another solution is to put in place a coating at the end of the molding in resurfacing to dress the songs of the room thus formed. However, this generates an additional operation that lengthens the production cycle and increases the number of manipulations of the part.

An object of the invention is to obtain a piece of song having a satisfactory aesthetic without complicating or lengthening the production.

For this purpose, a method of manufacturing a workpiece is provided, in which:

at least two layers of material are arranged in a mold with the interposition of a bezel between the two layers; and

A part of the mold is moved to sever one of the layers at a junction between this part and the telescope.

Thus, such a method makes it possible to cut only one of the layers of the part. It is then possible, at the outlet of the mold, to fold on the singing thus cut, or even on the opposite face, the layer which has not been

30 sectioned. This results in a workpiece edge having a satisfactory aesthetic. The method according to the invention may also have at least one of the following characteristics:

- The layer to be cut is a first of the layers, it immobilizes at least the first or the second layer relative to the bezel, preferably the second layer;

- Said part of the mold being a first part, immobilizing at least the first or the second layer relative to a second portion of the mold other than the bezel, preferably the second layer;

- we move the telescope; the bezel is moved parallel to a direction of movement of the part of the mold ensuring the sectioning;

the bezel is moved relative to the second part of the mold;

the sectioning layer is in contact with the telescope;

at least the layer relative to the sectioning is shaped, preferably at the same time as the sectioning;

at least one of the layers is formed between said part of the mold and another part of the mold that is different from the bezel;

- We locally crushes the layer relating to sectioning;

- The section is cut in a crushed area or to be crushed; a trough contiguous to an area of the room relating to sectioning is produced;

an outer edge with a curved profile is made contiguous to a zone of the part relating to sectioning;

- The second layer is folded on a edge of the first layer, and preferably on one side of the part opposite the face associated with the second layer;

the layer relating to sectioning has a honeycomb structure, for example honeycombs;

the second layer is cut off from a non-coinciding sectioning zone with a sectioning zone of the first layer; and - The second layer is cut by means of at least one of the bezel and a second portion of the mold other than the bezel; and

the layer relating to sectioning being a first of the layers, the second layer comprises a material of the following group: a woven material;

a nonwoven textile material;

- a metal.

The invention also provides a mold comprising:

first and second parts for shaping a workpiece; and a telescope extending facing the first part, in which the second part is arranged to cut at a junction of the second part with the telescope during a displacement of the second part with respect to the first part. .

The mold according to the invention may also have at least one of the following characteristics:

- The telescope is movable relative to the first part;

- The bezel is movable to slide relative to the first portion in a direction parallel to a relative sliding direction of the first and second parts; - The sectioning being a first sectioning, the mold comprises means for performing a second remote sectioning of the first sectioning; and

the means for performing the second sectioning comprise at least one of the telescope and the first part. Other features and advantages of the invention will become apparent in the following description of two preferred embodiments given as non-limiting examples with reference to the accompanying drawings in which:

FIGS. 1 to 7 are views in partial vertical section of a mold according to a first preferred embodiment of the invention and illustrate the different stages of the implementation of the method by means of this mold;

FIG. 8 shows the part edge during the completion step once the part has left the mold; - Figure 9 is a perspective view of the rear portion of a vehicle with a tailgate according to a second preferred embodiment of the invention;

- Figure 10 is a perspective view of the tailgate of Figure 9 in the closed position;

- Figures 11 and 12 are two sectional views along a median longitudinal vertical plane of the vehicle showing the tailgate of Figure 9 respectively in the open position and in the closed position;

FIG. 13 is a flowchart illustrating the manufacturing process of the tailgate of FIG. 9;

- Figure 14 is a schematic view of the tailgate forming mold; and - Figure 15 is a schematic view of a tailgate layer.

The different parts of the mold according to the first preferred embodiment of the invention will now be described with reference to FIG.

The mold 2 comprises a punch 4, a die 6 and a bezel 8.

The punch 4 and the die 6 are essentially of a conventional type. These two parts are intended for shaping the workpiece during the molding operation. In particular, the die 6 has an upper face 10 facing which the punch 4 extends. The punch 4 is slidably movable relative to the die 6 in the direction 12 illustrated in FIG. 4 and which is essentially vertical and perpendicular. on the face 10.

The telescope 8 is also mounted to slide relative to the die 6 and in addition to the punch 4. This sliding takes place in a direction 14 shown in Figure 2 and parallel to the direction

12. The telescope also extends opposite the upper face 10 of the matrix. Only a portion of the mold has been illustrated in section in Figures 1 to 7. The bezel is in fact a shaped shape that corresponds to at least one of the edges of the part intended to have a satisfactory aesthetic. When two or more of these edges are intended to undergo similar treatment, the bezel extends on several sides of the piece so that it comprises several shaped sections extending in a contour similar to these edges of the piece. When all the edges of the part are intended to undergo this treatment, the bezel will have a frame shape, the punch 4 extending opposite a central opening of this frame. The upper face 10 of the matrix comprises a central zone 16 intended to effect the shaping of the part. It also comprises a facet 18 contiguous to the zone 16 and extending facing a lower facet 20 of the telescope 8. The facets 18 and 20 extend at a distance from one another and are parallel to each other . The face 10 of the matrix 6 has a cavity 22 contiguous to the facet 18. The bottom of this cavity is plane, horizontal and parallel to the facet 18. In a complementary manner, the lower face of the telescope 8 has a relief 24 s' extending projecting from the facet 20 and having a horizontal plane top. This relief is intended to penetrate into the cavity 22 when the facets 18 and 20 are close to one another. The elements 22 and 24 then constitute a male-female combination. The facet 18 has an edge 25 contiguous with the cavity 22. The relief 24 has an edge 23 contiguous to the facet 20 and facing the edge 25. The two edges extend opposite one another so to cut a material extending between them when the relief 24 enters the cavity 22.

As illustrated in Figure 1, the outer side face 56 of the punch has an edge 54 formed by a right-angle profile and which is the junction between the vertical side face 56 and a horizontal lower facet 58 of the punch. Similarly, the telescope 8 has a ridge 60 with a right-angled profile and which constitutes the junction between a horizontal facet oriented towards the top and a vertical facet directed towards the inside of the mold. Edge 60 is opposite edge 54.

An example embodiment of the process according to the invention will now be described by means of the mold 2. In the present example, the method is intended for the manufacture of a part 26 illustrated in FIG. 8.

This part comprises a composite layer 27 comprising in this case three layers, namely a honeycomb core 28 honeycomb structure and on both sides of this core, covering the main faces thereof, two skins 30 and 32. Since the part has a generally planar shape, the cells of the core 28 extend perpendicularly to the plane of the part. This composite layer 27 is here made of a material called SANDWIFORM as marketed by Venture. The core 28 is here formed of polypropylene. Each of the skins 30 and 32 is made of thermoplastic material reinforced with glass fibers. In the method that will be described, the workpiece is shaped and simultaneously with the installation of a coating layer 34 intended to cover one of the skins and to form an appearance face of the room. This coating will for example be of woven or non-woven textile type. It may for example be a carpet or fabric.

In the first step illustrated in Figure 1, the punch 4 and the bezel 8 initially extend each spaced apart from the die 6 above it. The coating flank 34 is installed on the face 10 of the matrix 6 and in particular in the space provided between this face and the telescope 8. In a second step, the telescope 8 is slid so as to lower it towards the matrix 6 in the direction 14. The relief 24 enters the cavity 22. The coating 34 is immobilized by contact between the facets 18 and 20. And on the other hand an excess portion of the coating is cut between the relief 24 and the cavity 22 Fall 31 remains trapped between them. In the next step illustrated in FIG. 3, the SANDWIFORM material already constituted with its core 28 and its two skins 30 and 32 is put in place. This composite flank consists of the three layers resting on an upper face 40 of the 8. This flank therefore extends in particular away from the coating 34 and the bezel is interposed between the layer 34 and the composite layer 27 in the vertical direction.

During the next step illustrated in FIG. 4, the punch 4 is lowered in the direction 12 to slide it towards the die 6. The punch 4 comprises in particular on its lower face a relief 42 with rounded profile in an arc of a circle. . This relief constituting the lowest part of the punch, it comes first in contact with the skin 32 forming the upper face of the sidewall. The downward stroke of the punch causes the deformation of this flank and in particular the pivoting of its edge upwards and inwards, as illustrated in FIG. 4. This deformation and this pivoting continue as illustrated in FIG. the punch is at the height of the telescope. During its course, it pushes the composite material towards the coating 34. The part of the composite material located outside the part relative to the relief 42 bears against an inner face 44 of the bezel 8, inclined at 45 ° towards the punch 4. The edge of the material is lifted vertically supported on the corresponding faces of the bezel.

As illustrated in FIGS. 5 to 7, during its course in the direction of the matrix, the relief 42 of the punch locally crushes the part of the material 27 intended to form an edge zone of the part. It thus gives the upper face of this zone the shape of a trough 48. The face 10 of the die 6 has an edge 50 with a rounded profile in a complementary arc of the profile of the relief 42 as illustrated in FIG. edge 50 is intended to form on the side of the part opposite the chute 48 a rounded edge area 52.

The mold is configured so that, during the stroke of the punch 4, the edge 54 passes opposite the edge 60 of the bezel 8. Then, it is the face 56 of the punch which comes opposite the corresponding facet of the telescope. At this moment, the space existing between them is almost zero. These two edges provide on this occasion the shear of the entire thickness of the material 27 between them. This step therefore generates a drop 62 which is eliminated from the mold, and contributes to giving a sharp cut to the edge 64 of the workpiece at the end of the punch stroke, as illustrated in FIG. 7.

The material 27 is in contact with the coating 34 to which it is then intimately related.

It goes without saying that, prior to their introduction into the mold and / or during the operation of the mold, the various materials used will, if necessary, be suitably heated to the temperatures usually used for this type of manufacture.

With reference to FIG. 8, once the part has left the mold, a coating zone 70 projects beyond the edge 64 in the plane of the part. It can then be folded on this edge and on the face 72 of the part opposite to the coating 34. In particular, the coating may be arranged in the trough 48.

Thus, during this process, the coating 34 is put in place by leaving a portion which, at the end of the production, is glued reworked to cover the edge or the beginning of the opposite face of the room. As can be seen, during the process, the layers 28, 30 and 32 are in particular cut without cutting the coating 34 at the same place. In the present example, the coating 34 undergoes an independent cut.

Preferably, the cutting of the composite material 27 is carried out at a level which is shifted upwardly above the coating 34 by a height at least equal to the thickness of this coating. In this way, the composite material during cutting and shaping does not stretch the coating. Such stretching may otherwise tear the coating. It will be possible to implement the method for cutting the composite material 27 alone on one or more sides of the piece. without making this cut on all sides of the room. On the untreated sides by means of the method of the invention, it will suffice to make a sharp cut or to dispense with the possibility of folding the coating on the opposite face. Conversely, we can treat all sides of the room simultaneously.

It is observed that the operation of cutting the composite layer 27 takes place in the same movement as the shaping of the part, and in particular in the same direction and in the same direction. In addition, cutting and shaping are simultaneous. The same applies to the surplus for cutting the coating.

Various parts for a motor vehicle may be manufactured by means of the invention, and in particular according to this embodiment. This will be for example a boot floor, a chest shelf, a door panel, etc. A second preferred embodiment of the invention will be described.

In the present example, the part is a body part, namely a descending flap tailgate, that is to say, opening upwards. It could be alternatively another type of bodywork part, for example a side panel, a sidewall, a possibly retractable roof panel, or a tailgate opening downwards.

FIG. 9 illustrates a vehicle 102, in this case of the commercial vehicle type, presenting on its rear face an opening 104 for the loading of goods in the rear part of the vehicle. This opening 104 is closed by a hatch 106 according to the invention.

With reference to FIG. 10, the tailgate comprises a succession of lamellae 108 that are very precisely 12 in the present example, this number not being limiting. Each lamella has a substantially flat and rectangular shape in front view. The edges of the slats extend in coincidence with each other. The slats all have the same length measured in the horizontal transverse direction of the vehicle. The slats, however, do not all have the same height h. In this example, the slats are divided into two groups. The lamellae of the first group of 9 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 lamellae of the second group occupy positions 2, 3 and 4 starting from the highest lamella in the closed position as in Figure 10.

The hatch 106 is in one piece. It comprises a body layer 110 forming a body of each lamella, and a metal layer 112 in this case formed by a sheet. The layer 112 is visible from an external side of the tailgate as shown in FIG. 10. The body layer 110 comprises, as illustrated in FIG. 15, two glass fiber reinforced plastic walls 111 and a layer of alveolar structure 113 extending between these two walls. The honeycomb structure will be an expanded foam or a honeycomb structure for example. The plastic is in this case polypropylene.

The tailgate 106 comprises for each pair of consecutive strips 108 a hinge 115 formed by a film in one piece with the slats. The tailgate comprises two longitudinal edges 116 extending in the extension of two respective ends of the slats being distinct from these ends. As seen in Figure 10, each edge 116 is smooth and featureless and has a thickness less than a thickness of the slats.

As illustrated in FIG. 11, this rear hatch of hybrid structure can be retracted under the roof of the vehicle to make accessible the interior of the vehicle through the opening 4. The principle is similar to that of a roller shutter. Its opening may be driven by a motor or manually. The guiding of the tailgate during its movement is through slides in which slide the respective edges 116. The deformation of the tailgate during this movement is allowed by the hinges. Such a tailgate has the advantage that it does not require space behind the vehicle for the opening as would swing doors. Such a tailgate provides protection of the interior of the vehicle to water, gas, in respect of thefts, and acoustically. Its opening and closing can be fast by not taking more than 5 to 10 seconds. It is robust, resistant to indentation and small shocks. Thanks to the fact that the slats are in one piece with each other, the sealing function is well assured unlike in the case of a tailgate consisting of individual slats. The sheet is here a steel sheet designed to be deformed during opening and closing of the opening while remaining in its elastic range. Its thickness is here in 0.25 mm and 0.60 mm. The sheet used is prepainted or prelacked on the visible side 114 constituting the external face of the tailgate. The tailgate thus has a similar appearance to that of the body parts of the vehicle.

We will now describe an example of implementation of the method according to the invention for the manufacture of the tailgate 106.

In view of manufacturing, the sheet 112 is coated with an adhesive layer on its back side 116 as shown in Figure 14. This adhesive is in the heat-activated species to 180 ⁰ C. may for example use for this purpose the pre-glued sheet called "solbond" distributed by Arcelor.

The sheet is subjected to a first series of steps of the method as illustrated in FIG. 13. Initially, at step 117, in the form of a flank or from a spool, the sheet is stamped to shape it. This stamping 118 takes place between a die 120 and an unillustrated punch. In a subsequent step 122, the sheet 112 is transferred with the die 120 under the forming press which will be used to shape the tailgate itself. The die 120 whose shape it and the press 136 form the forming mold of the tailgate. The unsized face 114 of the sheet 112 is in contact with the die 120, whose shape it conforms. This mold is the same type as that of Figure 1 corresponding to the first embodiment.

Alternatively, it could be provided that the stamping takes place in a tool independent of the forming mold that will be used for shaping the tailgate itself.

Regardless of this first set of steps, a second set of steps is performed on the body layer 110.

In the present example, it is made of a material called "sandwiform" distributed by Venture Industries. As indicated above, this material is here formed by a core 113 of polypropylene honeycomb structure on either side of which are disposed layers 111 of plastic reinforced with glass fibers. It may still 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 of polypropylene reinforced with mats of glass fibers. The soul will have a thickness of between 10 and 20 mm.

The three layers constituting the body layer 110 are preassembled in step 130 in a manner known per se in a heated mold. The product thus constituted is heated in step 132 in an oven to be brought to a temperature between 150 and 250 ⁰ C and in this case 200 ⁰ C. Once heated to temperature, the layer 110 is transferred to the step 134 to forming die 120, 136 shown in FIGS. 1 and 14.

In this mold, the sheet 112 is disposed with its painted or varnished face 114 in contact with the matrix 120 and above the sheet 110. The punch 136 of the mold is placed above the layer 110. As previously, the bezel 108 is interposed between the layer 110 and the sheet 112. The mold is again shaped so as to perform during its closure the cutting of the layer 110, shaping the tailgate and if necessary the cutting of the sheet. Knowing that the glue of the sheet 112 is active at a temperature of 18O ⁰ C and that the sheet is in contact with the layer heated 110, the closing of the mold causes the bonding of the sheet on the layer 110. (It may be provided alternatively to preheat the sheet before adding it to the mold in order to activate the glue). 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 die 120 causes cooperating with the piston or press 136 the local crushing of the body layer 110 so as to crush the honeycomb core by producing the hinges 115. Thus, at the hinges, the body layer 110 sees its reduced thickness of about 90% compared to the thickness of the uncrushed portions of this layer. Localized hinges 115 in the form of a film are thus produced by local compression of the sandwich. These hinges are rugged enough to withstand a large number of opening and closing cycles, up to 130,000 cycles for a utility application. The mold is operated at a pressure between 10 and 20.10 ⁶ Pa. The hatch thus produced has a high rigidity for a relatively low weight.

The other aspects of the constitution and operation of the mold are identical to what has been described with reference to the first embodiment. The invention makes it possible to achieve with this press stroke a piece made of lamellae bonded together and therefore sealed. The manufacturing process is particularly simple compared to that involving the assembly of individually manufactured slats.

Note that the layer 110 is cut at the periphery to delimit edges 116 during closure of the mold. The rim described in the previous embodiment is this time replaced by the crimping of the sheet on the opposite face of the layer 110, as in Figure 8. Thus, the sheet is given larger dimensions than the other parts of the sheet. the piece to be able to fold the edges of the sheet once the piece finished to give it a better appearance. We can predict when same step that a seal 119 is overmolded at the periphery of the tailgate as shown partially in Figure 10.

The sheet gives the tailgate the appearance of a body part. In addition, no appearance defect related to the cells of the honeycomb in the sandwich does not appear on the sheet.

It may be provided to form the sandwich of step 30 before its introduction into the mold for its assembly with the sheet under a pressure of 5 to 10.10 ⁶ Pa.

According to the second embodiment, it is possible to manufacture different external bodywork parts, such as a load stop panel, etc.

Of course, many modifications can be made to the invention.

The coating may be immobilized in the mold by means other than the telescope.

We can predict that the telescope is fixed relative to the matrix and not mobile.

Composite parts having the most varied structures can be made by this method. In particular, the number of layers can be modified. It will thus be possible to replace the composite layer 27 with one or more stacked layers. It may be the same for layer 34. We can dispense with a honeycomb core. Finally, we can choose thermoplastic materials of different types (polypropylene, polyethylene, etc.).

Claims

1. A method of manufacturing a workpiece (26; 106), characterized in that: - at least two layers of material (27,34; 110,112) are arranged in a mold (2) with the interposition of a bezel (8 108) between the two layers; and moving a portion of the mold (4; 136) to sever one (27; 110) of the layers at a junction between that portion and the bezel.

2. Method according to the preceding claim, characterized in that the layer (27; 110) to be sectioned being a first of the layers, is immobilized at least the first or the second layer relative to the bezel (8; 108), preferably the second layer (34; 112).

3. Method according to any one of the preceding claims, characterized in that the layer to be sectioned (27; 110) being a first of the layers and said part (4; 136) of the mold being a first part, at least the first or second layer relative to a second portion of the mold (6; 120) other than the bezel, preferably the second layer (34; 112).

4. Method according to any one of the preceding claims, characterized in that the bezel (8; 108) is moved.

5. Method according to any one of the preceding claims, characterized in that moves the telescope (8; 108) parallel to a direction of displacement (12) of the mold part (4; 136) ensuring sectioning.

6. Method according to any one of the preceding claims, characterized in that said portion of the mold (4; 136) being a first part, the bezel (8; 108) is moved relative to a second part of the mold (6; 120).

7. Method according to any one of the preceding claims, characterized in that the layer (27; 110) relative to the sectioning in contact with the bezel (8; 108).

8. Process according to any one of the preceding claims, characterized in that at least the layer (27; 110) relating to the sectioning, preferably at the same time as the sectioning, is shaped.

9. Process according to any one of the preceding claims, characterized in that at least one (27; 110) of layers is formed between said part of the mold (4; 136) and another part of the mold ( 6; 120) different from the telescope (8; 108).

10. Method according to any one of the preceding claims, characterized in that locally crushes the layer (27; 110) relating to sectioning.

11. Method according to any one of the preceding claims, characterized in that the layer (27; 110) is cut in a crushed area or to be crushed.

12. Method according to any one of the preceding claims, characterized in that a chute (48) contiguous to a zone of the part relating to sectioning is produced.

13. Process according to any one of the preceding claims, characterized in that an outer edge (52) with a curved profile contiguous to a zone of the part relating to sectioning is produced.

14. Method according to any one of the preceding claims, characterized in that the sectioning-related layer being a first of the two layers, the second layer (34; 112) is folded on a edge of the first layer (27; 110). , and preferably on one face (72) of the part opposite to the face associated with the second layer.

15. The method as claimed in claim 1, wherein the layer (27;

16. Method according to any one of the preceding claims, characterized in that the layer (27; 110) relating to the sectioning being a first of the layers, the second layer (34; 112) is sectioned to a non-coinciding sectioning zone with a sectioning zone of the first layer.

17. A method according to any one of the preceding claims, characterized in that the sectioning-related layer being a first of the layers and said part of the mold (4; 136) being a first part, the second layer (34; ) by means of at least one of the bezel (8; 108) and a second portion (6; 120) of the mold other than the bezel.

18. Method according to any one of the preceding claims, characterized in that the sectioning-related layer being a first of the layers, the second layer comprises a material of the following group:

- a woven material; a nonwoven textile material (10);

a metal (112).

19. Mold (2) comprising:

first and second parts (4,6; 136,120) for forming a workpiece; and - a telescope (8; 108) extending opposite the first portion (6; 120); characterized in that the second portion (4; 136) is arranged to cut at a junction of the second portion with the bezel (8) upon movement of the second portion (4; 136) relative to the first portion (4; part (6).

20. Mold according to the preceding claim, characterized in that the bezel (8; 108) is movable relative to the first portion (6; 120).

21. Mold according to claim 19, characterized in that the bezel (8; (12) relative sliding of the first and second parts (4,6; 136,120).

22. Mold according to any one of claims 19 to 21, characterized in that the sectioning being a first sectioning, the mold (2) comprises means (6,8, 120,108) for performing a second remote sectioning of the first sectioning .

23. Mold according to the preceding claim, characterized in that the means for making the second sectioning comprise at least one of the bezel (8; 108) and the first portion (6; 120).