FR2928579A1 - Lining assembly for motor vehicle, has substrate delimiting injection hole that is closed by closure element to block passage of foam from inner volume towards exterior of substrate, where element is formed by skin having closure surface - Google Patents

Abstract

The assembly (2) has a rigid substrate (4) and a flexible lining skin (6) to define an inner volume (8) for injection of foam. The substrate delimits an injection hole (12) emerging in the inner volume, and a closure element closes the hole for blocking the passage of the foam from the inner volume towards an exterior of the substrate. The closure element is formed by the skin having an inner closure surface (14). A foam layer (10) occupies the inner volume, and is stuck to the substrate. Independent claims are also included for the following: (1) a method for fabricating a lining assembly of a motor vehicle (2) a mold for fabricating a lining assembly of a motor vehicle.

Description

Set of automobile vehicle trim. The present invention relates to a motor vehicle trim assembly, of the type comprising a substrate and a covering skin together defining an internal foam injection volume, the substrate delimiting at least one injection hole opening into said internal volume. , the dressing assembly comprising at least one closure member adapted to close the injection hole to prevent the passage of the foam from the internal volume to the outside of the substrate. The document FR-A-2 898 537 describes a motor vehicle trim assembly comprising a substrate and a covering skin together defining an internal volume of foam injection, and a foam layer occupying the internal volume. The substrate delimits an injection hole opening into said internal volume and has, inside the internal volume, an elastic member for closing the injection hole.

For the manufacture of the dressing assembly, the skin and the substrate are arranged in a mold so as to form said internal foam injection volume. Then, an injection nozzle is disposed in the injection hole, against the resilient closure member, so as to open at its center and thus inject a fluid plastic material within said internal volume.

Upon withdrawal of the injection nozzle, the elastic member returns to its closure configuration of the injection hole. Nevertheless, the cost of manufacturing the trim assembly is relatively important, because it is necessary to report a shutter member on the substrate.

An object of the invention is to provide a dressing assembly whose quality of the foam layer is satisfactory and for a relatively low manufacturing cost. For this purpose, the subject of the invention is a covering assembly of the aforementioned type, characterized in that the closure element is formed by the covering skin.

According to particular embodiments, the trim assembly comprises one or more of the following characteristics, taken in isolation or in any technically possible combination: the covering skin has a sealing surface capable of closing off the injection hole from the inside; the substrate comprises at least one internal tab for retaining the covering skin, the internal retaining tab extending inside said internal volume; - The motor vehicle trim assembly comprises a foam layer occupying said internal volume, the skin dressing adhering to the foam layer and the foam layer adhering to the substrate; and the covering skin is, around the injection hole, glued against the substrate.

The invention also relates to a method for manufacturing a motor vehicle assembly comprising a substrate and a covering skin, the substrate delimiting at least one injection hole, the method comprising: the arrangement of the substrate and the skin in a mold and the closure of the mold so that the substrate and the skin together define an internal volume of foam injection, said injection hole opening into said internal volume, the external access to the injection hole being cleared; the provision of an injection nozzle having an outlet orifice so that the outlet orifice communicates with the injection hole of the substrate and with said internal foam injection volume; the injection, through the outlet orifice of the nozzle, of a fluid plastic material intended to form a layer of foam in said internal volume, between the skin and the substrate, characterized in that the process comprises, after injection, a step of sealing the injection hole through the skin.

According to a particular embodiment, the method comprises one or more of the following characteristics, taken alone or in any technically possible combination: the shut-off step comprises a step of deforming the skin between a configuration spaced apart from the an injection hole in which the skin is spaced from the injection hole and an injection hole sealing configuration in which the skin is applied against the substrate around the injection hole; the shut-off step comprises actuating a jack of the mold, a retracted configuration of the jack in which the skin is spaced from the injection hole to an extended configuration of the jack in which the skin closes the injection hole. The subject of the invention is also a mold for manufacturing a motor vehicle trim assembly as defined above, the mold having a skin-receiving surface, and a receiving surface for the substrate, characterized in that the mold comprises: - an access port of a foam injection nozzle in the mold; a jack having a retracted configuration in which the jack is substantially at or away from said receiving surface of the trim skin, and an expanded configuration in which the jack protrudes with respect to said receiving surface of the covering skin, the jack being placed opposite the access orifice of the nozzle. The invention also relates to a molding unit comprising a single injection nozzle, characterized in that it comprises at least two molds as described above, the nozzle being able to perform the foam injection sequentially in each mold. The invention will be better understood on reading the description which follows, given solely by way of example and with reference to the appended drawings, in which: FIG. 1 is a diagrammatic sectional view of a set of FIGS. cladding according to the invention, arranged in a manufacturing mold according to the invention, and illustrating a step of a manufacturing method according to the invention; - Figure 2 is an enlarged view of a detail II of Figure 1; - Figure 3 is a schematic sectional view along the line III-III of Figure 2; - Figure 4 is a view similar to Figure 2 illustrating a subsequent step of the manufacturing method according to the invention; and - Figure 5 is a view similar to Figures 2 and 4 illustrating a subsequent step of the manufacturing method according to the invention.

FIG. 1 illustrates a step of injection of a method of manufacturing a trim assembly 2 of a motor vehicle. The covering assembly 2 comprises a substantially rigid substrate 4 and a flexible skin 6, together defining an internal volume 8 of foam injection. After the injection step, the covering assembly 2 comprises a layer of foam 10 occupying the internal volume 8. In what follows, the terms inside and outside refer to the internal volume 8.

The foam layer 10 is adhesive. It adheres, after solidification, to the substrate 4 and the skin 6, so that the skin 6 is carried by the foam layer 10, the moussel0 layer being carried by the substrate 4. The foam layer 10 is for example made expanded polyurethane.

The substrate 4 is intended to be fixed on the body elements (not shown) of the vehicle. It is for example intended to be made of polyolefin thermoplastic material, homopolymer or copolymer, optionally comprising mineral fillers or a reinforcement with glass fibers. It can be made of ABS-PC (acrylonitrile-butadiene-styrene and polycarbonate) optionally reinforced with glass fibers. These materials have a rigidity to fulfill a support function. The substrate 4 defines a hole 12 for injection opening into the internal volume 8 and outside the substrate 4. The injection hole 12 connects the outside of the substrate 4 to the internal volume 8, and serves for the injection of the foam in the internal volume 8. The skin 6 is intended to be placed next to a motor vehicle user in the passenger compartment of the vehicle. It is for example formed of elastomeric thermoplastic such as thermoplastic polyurethane (TPU) or thermoplastic olefin (TPO). Flexible polyvinyl chloride (PVC), rubber or silicone can also be used. The flexible skin 6 has an internal sealing surface 14 adapted to close the injection hole 12 from the inside after the injection step. Indeed, the surface 14 of the skin 6 is deformable between an initial configuration spaced from the substrate 4 around the injection hole 12 and a closure configuration of the injection hole 12. The skin 6 thus forms a closure element of the injection hole 12. As illustrated in Figure 1, the method of manufacturing the trim assembly 2 is implemented by means of a molding unit 20 comprising a single injection nozzle 22, and a plurality of injection molds 24. The injection nozzle 22 is able to sequentially perform the injection of foam into each mold 24. It is for example moved from one mold 24 to the other by a robot. Each mold 24 comprises a mechanism 26 of deformation of the skin 6 between its spaced configurations and closure of the injection hole 12. The molds 24 will be described in more detail below. The covering assembly 2 is of a thickness much smaller than its dimensions in directions perpendicular to its thickness. The substrate 4 comprises, over its entire periphery, a peripheral rim 28 extending along the thickness of the covering assembly 2. The peripheral rim 28 is, in the mold 24, sealing against the skin 6. The injection hole 12 is located near the peripheral rim 28. The injection hole 12 is accessible through the injection nozzle 22 and able to communicate with an outlet orifice 30 of the nozzle 22, for example waterproof way. For this purpose, the substrate 4 comprises, outside, a seal 32 surrounding the injection hole 12. The substrate 4 has an annular rib 34 forming an outer annular shoulder for placing the seal 32. A inside the internal volume 8, the substrate 4 comprises three tabs 38 for retaining the skin 6. The tabs 38 extend inside the internal volume 8 and are able to let the foam flow between them. The tabs 38 each have a general shape of plate, whose contour is for example trapezoidal. The tabs 38 are spaced apart and substantially parallel to each other (see FIG. 4). In the mold 24, the skin 6 is thus wedged both by the peripheral rim 28 and by the retaining lugs 38, against the mold 24. The skin 6 comprises a deformation portion 39, extending between the retaining tabs 38 and the peripheral flange 28, facing the injection hole 12. The deformation portion 39 is able to deform so as to close the injection hole 12, without deforming a stationary portion 40 of the skin 6 extending on the other side of the retaining lugs 38. The retaining lugs 38 have a primary bearing surface 42 on the skin 6, as well as a secondary surface 44 for bearing on the skin 6, the surfaces 42 and 44 are adjacent and form between them a non-zero angle, preferably greater than or equal to 30 °. Before deformation of the skin 6, only the primary surface 42 rests on the skin 6, while the two primary and secondary surfaces 42 and 44 bear on the skin 6 after deformation of the skin 6. As illustrated in FIGS. 5, each mold 24 comprises an upper portion 48 having a complementary surface 49 for receiving the substrate 4, and a lower portion 50 having a complementary surface 51 for receiving the skin 6.

The upper part 48 delimits an orifice 52 for access of the nozzle 22 allowing access of the nozzle 22 facing the injection hole 12 of the substrate 4. When the nozzle 22 bears against the seal 32, the orifice 30 of the nozzle 22 communicates sealingly with the internal volume 8. The lower portion 48 of the mold 24 comprises, as illustrated in Figures 1, 2, 4 and 5, a cylinder 56 having a piston 58, for example pneumatic , and a pusher 60 slidably mounted and secured to the piston 58 substantially facing the access port 52 and thus the nozzle 22. The pusher 60 has a head 64 bearing on the skin 10. The head 64 defines a centrally recess 66, and has around the recess 66, a peripheral surface 68 bearing on the skin 6. The head 64 thus has a bowl shape. The pusher 60 is moved by the piston 58 between a retracted position in which the head 64 of the pusher 60 is substantially at the receiving surface 51, and an extended position in which the head 64 is projecting inwards, c that is to say towards the substrate 4, with respect to the receiving surface 51. In the retracted position of the head 64, the skin 6 extends, facing the pusher 60, in the extension of the receiving surface 51. In the deployed position of the pusher 60, the deformation portion 39 of the skin 6 is deformed and pressed against the substrate 4, at and around the injection hole 12. The deformation portion 39 of the skin 6 is then spaced from the receiving surface 51. The recess 66 is opposite the injection hole 12 and the outlet orifice 30. The peripheral surface 68 surrounds the injection hole 12.

The manufacturing method will now be described in more detail with reference to FIGS. 2, 4 and 5. In a first step, the substrate 4 is put in place on the upper part 48 of the mold 24, while the skin 6 is put into place. place on the lower portion 50 of the mold 24. The upper and lower 48,50 are brought closer to each other, and the mold 24 is closed. Once the mold 24 closed, the substrate 4 and the skin 6 together define the internal volume 8 of foam injection. The peripheral flange 28 and the retaining tabs 38 are placed in abutment against the skin 6. The skin 6 is wedged between the receiving surface 51 of the lower part 50 of the mold 24 and the retaining tabs 38, and between the receiving surface 51 and the peripheral rim 28. The injection nozzle 22 is brought into its position in FIG. 2 in which it bears sealingly against the seal 32. In this position of the nozzle 22, the outlet orifice 30 of the nozzle 22 is opposite the injection hole 12 and communicates sealingly with the injection hole 12 and the internal volume 8 of foam injection. In a subsequent step illustrated in FIG. 4, the nozzle 22 proceeds to inject a foam in the fluid state, which flows by gravity and pressure into the entire internal volume 8 so as to occupy the entire internal volume 8. Indeed, the injection hole 12 corresponds substantially to the highest point of internal volume 8. Once a predetermined amount of foam injected into the internal volume 8, the pusher 60 is moved by the piston 58 to and to its deployed position protruding. During this movement, it pushes the deformation portion 39 towards the substrate 4. In the deployed position, the inner surface 14 of the skin 6 located opposite the deformation portion 39 is applied against the substrate 4 and closes the hole d Injection 12. The skin 6 is wedged between on the one hand the retaining tabs 38 and the peripheral rim 28 and on the other hand the pusher 60 (see Figure 5).

The immobile part of the skin 6 extending on the other side of the retaining tabs 38 is not deformed by the action of the pusher 60, thanks to the jamming action of the retaining tabs 38. The nozzle injection 22 is removed substantially simultaneously with the movement of the pusher 60 to its deployed position. Once the layer of foam 10 has solidified, the pusher 60 is returned to its retracted position and the mold 24 opened, so as to remove the dressing assembly 2 thus formed and to prepare the mold 24 for another molding. In a subsequent step that is not illustrated, the part of the covering assembly 2 substantially corresponding to the part illustrated in FIGS. 2, 4 and 5, is cut from the remainder of the covering assembly 2. Indeed, this part is unsightly, because of the deformation of the skin 6 and the absence of foam between the substrate 4 and the skin 6. This part is only useful for the manufacture of the covering assembly 2. As a variant nevertheless, this unsightly part is kept but hidden from the user. In another variant, it is visible. The invention has the advantage of allowing the closure of the injection hole 12 quickly after the injection of the foam. Foam losses through the injection hole 12 are low and the quality of the foam layer 10 is high.

In addition, the manufacturing cost of the cladding assembly 2 is low because the invention dispenses with the presence of a closure element attached to the substrate 4. In fact, if the cost of the mold 24 is greater because of the jack 56, the economy of scale achieved for the substrate 4 reduces the cost of manufacture of the trim assembly 2. In addition, the actuation of the jack 56 and thus the closing of the hole d injection 12 is controlled independently of the injection nozzle 22. It is for example possible to start moving the pusher 60 to its deployed position before the removal of the nozzle 22, so as to further limit the loss of foam.

The flared shape at its center of the head 64 limits the pressure of the foam at the injection hole 12. The skin 6 matches the shape of the head 64 and the recess 66 is thus partially occupied by the foam.

Finally, the closure of the injection hole 12 allows a sequential injection made with the molding unit 20. In this way, a single injection nozzle 22 is used for the manufacture of several sets of covering 2 in different molds. 24, it is for example four molds 24.

Alternatively, the number of internal retaining tabs 38 is different. The substrate 4 has for example four.

Claims (10)

1.- trim assembly (2) of a motor vehicle, of the type comprising a substrate (4) and a covering skin (6) together defining an internal volume (8) of foam injection, the substrate (4) delimiting at least one injection hole (12) opening into said internal volume (8), the covering assembly (52) comprising at least one closure element capable of closing off the injection hole (12) to prevent the passage of the foam from the internal volume (8) towards the outside of the substrate (4), characterized in that the closure element is formed by the covering skin (6). 2. Set of trim (2) of a motor vehicle according to claim 1, characterized in that the covering skin (6) has a sealing surface (14) adapted to close the injection hole (12). from the inside. 3. A trim assembly (2) of a motor vehicle according to claim 1 or 2, characterized in that the substrate (4) comprises at least one inner lug (38) for retaining the covering skin (6), the internal retaining tab (38) extending inside said internal volume (8). 4. - The motor vehicle trim assembly according to any one of the preceding claims, characterized in that it comprises a layer of foam (10) occupying said internal volume (8), the covering skin (6) adhering to the foam layer (10) and the foam layer (10) adhered to the substrate (4). 5. A motor vehicle trim assembly according to claim 4, characterized in that the covering skin (6) is, around the injection hole (12), glued against the substrate (4). 6. A method of manufacturing a trim assembly (2) of a motor vehicle comprising a substrate (4) and a covering skin (6), the substrate (4) delimiting at least one injection hole (12). ), the method comprising: - arranging the substrate (4) and the skin (6) in a mold (24) and closing the mold (24) so that the substrate (4) and the skin (6) define together an internal volume (8) of foam injection, said injection hole (12) opening into said internal volume (8), the external access to the injection hole (12) being disengaged; an injection nozzle (22) having an outlet (30) so that the outlet (30) communicates with the injection hole (12) of the substrate (4) and with said internal volume (8) of foam injection; the injection, through the outlet orifice (30) of the nozzle (22), of a fluid plastic material intended to form a layer of foam (10) in said internal volume (8), between the skin (6); ) and the substrate (4), characterized in that the method comprises, after the injection, a step of closing the injection hole (12) by the skin (6). 7. - Manufacturing method according to claim 6, characterized in that the sealing step comprises a step of deformation of the skin (6) between a spaced configuration of the injection hole (12) in which the skin (6) ) is spaced from the injection hole (12) and an injection hole sealing configuration (12) in which the skin (6) is applied against the substrate (4) around the injection hole (12). 8. A method of manufacturing a trim assembly (12) of a motor vehicle according to claim 6 or 7, characterized in that the closing step comprises actuating a jack (56) of the mold ( 24), a retracted configuration of the jack (56) in which the skin (6) is spaced from the injection hole (12) to an expanded configuration of the jack (56) in which the skin (6) closes the injection hole (12). 9. Mold (24) for manufacturing a trim assembly (2) of a motor vehicle according to any one of claims 1 to 5, the mold (24) having a receiving surface (51) of the skin of cladding (6), and a receiving surface (49) of the substrate (4), characterized in that the mold (24) comprises: - an access orifice (52) of a nozzle (22) for injecting foam in the mold (24); a jack (56) having a retracted configuration in which the jack (56) is substantially at or away from said receiving surface (51) of the skin (6), and an expanded configuration in which the jack (56) protrudes with respect to said receiving surface (51) of the covering skin (6), the jack (56) being placed facing the access orifice of the nozzle (22). 10.- molding unit (20) comprising a single injection nozzle (22), characterized in that it comprises at least two molds (24) according to claim 9, the nozzle (22) being adapted to perform the foam injection sequentially into each mold (24).