FR2890887A1 - Manufacture of vehicle interior trim component covering air bag includes support being held during formation of rupture line to avoid compressing filling material - Google Patents

Abstract

The procedure, which includes the formation of a rupture line for an air bag in a trim component comprising an outer skin (22), a rigid support (20) and an intermediate layer of a supple filling material (24), uses a cutting tool (46) forced into the component from the support side so that it passes through the support and filling material and leaves a groove (36) in the inner surface of the skin. It differs in that the support is held during the cutting process to prevent the filling material from being compressed. During the process the trim component rests on the surface (44) of a frame (42), and the support is held up by connectors (26) linked via couplings (58) to actuators (52) that control their positions.

Description

The present invention relates to a method of manufacturing a skin

  interior of a motor vehicle safety airbag, comprising an outer skin of appearance, a rigid support and a flexible filling material disposed between the skin and the

  support, the covering being intended to break along a line of rupture to allow the passage of the airbag during its deployment, the method being of the type comprising: a step of assembling the skin, the support and the filler material; and a step of forming the break line by means of a cutting member driven into the casing on the side of the support so as to pass through the support and the filling material and to cut one side of the skin facing the side of the support.

  The document US 2002/0043144 describes a manufacturing process of the aforementioned type, wherein the cladding is placed in abutment by its skin against a bearing surface, and the cutting member is depressed on the side of the support in the cladding. controlling the position of the cutting member with respect to the bearing surface, so as to control the depth of the break line, and to ensure that this depth is sufficient to allow it to break when the pad is triggered. inflatable safety.

  However, this method is not satisfactory in all respects, particularly in the case of a covering comprising a foam disposed between the skin and the support. There remains a risk that the breaking line does not break during the release of the airbag, and, furthermore, deterioration of the covering may occur during the implementation of the process, this deterioration may adversely affect from the life of the vehicle to the appearance of the dressing.

  An object of the invention is to provide a method of the aforementioned type, to increase the reliability and quality of manufacture of an interior trim of a motor vehicle with a break line.

  For this purpose, the invention provides a method of the aforementioned type, characterized in that during the step of forming the rupture line, the support is retained to prevent the compression of the filling material during the driving of the cutting member through the support.

  According to other embodiments, the method comprises one or more of the following characterisers, taken alone or in any technically possible combination: during the step of forming the rupture line, the cladding resting against a surface of a frame, and retaining the support using at least a connecting portion of the support engaged with at least one connecting member connected to a frame; the or each connecting member is fixed relative to the frame; - The or each connecting member is carried by at least one actuator for controlling the position of the connecting member relative to the surface; the or each actuator makes it possible to control the position of the or each connecting member in a direction substantially perpendicular to the surface; and the or each actuator is a linear actuator.

  The invention and its advantages 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 schematic perspective view of the passenger compartment of a motor vehicle, showing a dashboard covered with a covering obtained according to a process according to the invention; - Figure 2 is a schematic sectional view of the casing of Figure 1, along the line II-11; and - Figure 3 is a view similar to that of Figure 2, illustrating the cladding disposed in a cutting machine of a break line adapted to implement a method according to the invention.

  As shown in Figure 1, the dashboard 2 of a motor vehicle 3 is covered, on the passenger side (right in Figure 1), an inner lining 4 extending between a door 6 of box with gloves and an upper panel 8 located under the windshield 10.

  The covering 4 comprises a region 12 masking an airbag 14 housed in the dashboard 2.

  In a manner known per se, in the rest position (FIG. 1), the cushion 14 is folded in an associated housing situated in the dashboard 2 under the region 12, and, in the deployed position, the cushion 14 is inflated so as to protect the head and bust of the passenger against impact with the dashboard 2.

  To allow the passage of the cushion 14 through the covering 4, the region 12 has a rupture line 16 delimiting in the region 12 a flap 18.

  The line 16 has a lower resistance than the rest of the region 12, so that during the deployment of the cushion 14, the casing 4 breaks along the line 16 thus forming the flap 18 which deviates to pass the cushion 14.

  The line 16 defines for example an open contour, so that the flap 18 deviates by articulating around an intact zone 19 of the region 12 located between two ends of the line 16 and forming a hinge.

  As shown in FIG. 2, the covering 4 consists of several superposed layers, including a rigid support 20, an aspect skin 22 constituting the visible layer of the covering 4 when it is fixed in the passenger compartment. and an intermediate layer 24 located between the support 20 and the skin 22, and made of a flexible material such as a synthetic foam.

  The support 20 gives the covering 4 its structural rigidity, the skin 22 gives it an aesthetic appearance, and the foam 24 gives it a soft and pleasant touch when the user applies his fingers to the skin 22.

  The support 4 comprises tongues 26 projecting from the support 20 on the side opposite the skin 22. The tongues 26 are for example two in number. Each tongue 26 is provided with a hole 28.

  The rupture line 16 is defined by a groove 30 made in the cladding 4 on the side of the support 20.

  The bleeding 30 sinks into the skin 4 towards the skin 22 from a rear face 32 of the support 20 opposite the skin 22. The bleeding 30 passes through the support 20 and the foam 24, and enters the skin 22 without crossing it. Thus, the groove 30 does not open on a visible face 34 of the skin 22 opposite the support 20. The bottom of the groove 30 is constituted by a notch 36 formed in a non-visible face 37 of the skin 22 facing the support 20 .

  Thus the bleeding 30 is invisible on the side of the skin 22, and the notch 36 is a line of lesser thickness in the skin 22, promoting the initiation of a tear when a force is applied to the flap 18.

  The groove 30 extends continuously along the line 16. In a variant, the groove 30 extends in dashed lines along the line 16.

  For the manufacture of the covering 4, the support 20, the foam 24 and the skin 22 are previously assembled, for example and in a manner known per se, by arranging the skin 22 and the support 20 in a mold in which is then injected the foam 24 melts. After cooling, the covering 4 is demolded.

  Then, the line 16 is formed in the cladding 4.

  To do this, as illustrated in FIG. 3, the casing is provided in a machine 40 comprising a frame 42 having a bearing surface 44, a cutting member 46 mounted to move above the surface 44 with the aid of FIG. displacement means 48, heating means (not shown) for maintaining the member 46 at a predetermined temperature, and a control unit 50 connected to the displacement means 48 for controlling the movement of the member 46 relative to the surface 44.

  In a manner known per se, the displacement means 48 allow to move the member 46 perpendicular to the surface 44 (Arrow f1) and parallel to the surface 44 (Arrow f2) in two directions perpendicular to each other.

  The machine 40 also comprises actuators 52, for example two in number, and in the form of linear cylinders of the hydraulic or electric type, with double action.

  Each jack 52 comprises a body 54 fixed to the frame 42 and a rod 56 movable relative to the body 54 substantially perpendicular to the surface 44 (arrows f3) and carrying at its free end a hook 58. Each jack 52 comprises motor means allowing to control the position of its rod 56 relative to its body 54.

  The unit 50 is connected to each cylinder 52 for the purpose of controlling it.

  The casing 4 is supported by its skin 22 against the surface 44. The support 20 is oriented so that the tabs 26 extend towards the cylinders 52. The casing 44 is held against the surface 44, for example by creating a gap between the surface 44 and the skin 22 by means of channels 60 opening to the surface 44 and connected to a vacuum source (not shown). The hooks 58 are engaged in the holes 28.

  The unit 50 controls the cylinders 52 so as to maintain the support 20 substantially immobile with respect to the surface 44.

  Then, the unit 50 controls the heating and the displacement of the member 46, preferably with respect to the surface 44, so as to form the groove 30 by inserting the member 46 into the casing 4 on the side of the support 20 , so as to pass through the support 20 and the foam 24 and to cut the skin 22 without passing through it.

  For this purpose, the unit 50 permanently controls the relative position of the lower end of the cutting member 46 and the surface 44, and compares it to the minimum distance to remain after the member 46 is fully depressed. .

  During the depression of the member 46, the heating of the member 46 facilitates its passage through the support 20 and the foam 24. Nevertheless, the member 46 first encounters the support 20 which tends to sink in the direction of the skin 22 by compression of the foam 24.

  The cylinders 52 holding the support 20 prevent the support 20 from sinking. Thus, no energy is dissipated in a compression of the foam 24. In addition, the insertion and removal of the cutting member 46 are performed more rapidly, which avoids deterioration of the support 20, and in particular the foam 24, due to the prolonged presence of the member 46 which is hot inside the foam 24. It follows that the foam 24 will not be damaged around the bleeding 30, and that the dressing 4 does not will not deteriorate over time.

  The possibility of movement of the cylinders 52 makes it possible to use the machine for different types of covering 4.

  Alternatively, retaining means such as hooks 58 fixed relative to the frame 42 are used to retain the support 20. In this case, it is possible to direct the hooks 58 in the same direction and parallel to the surface 44. Thus , the covering 4 is brought parallel to the surface 44 to be engaged with the hooks 58 (Arrow f4).

  Several successive insertions and withdrawals of the cutting member 46 make it possible to form the continuous or dotted line 30 along a line having the desired contour.

  Alternatively, the machine 40 comprises a cutting member having the contour of the line 16. Thus, a single insertion operation of the cutting member 46 in the casing 4 substantially perpendicular to the surface 44 (arrow f1) is necessary to form line 16.

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Claims (6)

  A method of manufacturing an inner liner for masking a motor vehicle safety airbag (14), comprising an outer skin of appearance (22), a rigid carrier (20), and a flexible filler material (24) disposed between the skin (22) and the support (20), the covering (4) being intended to break along a line (16) to allow the passage of the airbag (14) during its deployment, the method being of the type comprising: - a step of assembling the skin (22), the support (20) and the filling material (24); and a step of forming the breaking line (16) by means of a cutting member (46) pressed into the cladding (4) on the side of the support (20) so as to pass through the support (20) and the filling material (24) and notching a face (37) of the skin (22) facing the support side (20); characterized in that, during the step of forming the break line (16), the carrier (20) is retained to prevent compression of the filler material (24) upon insertion of the cutting member ( 46) through the support (20).   2. Manufacturing method 1, characterized in that, during the step of forming the rupture line (16), the casing (4) is placed in abutment against a surface (44) of a frame (42). ), and retaining the support (20) with at least one connecting portion (26) of the support (20) engaged with at least one connecting member (58) connected to a frame (42).   3. Method according to claim 2, characterized in that the or each connecting member (58) is fixed relative to the frame (42).   4. Method according to claim 2, characterized in that the or each connecting member (58) is carried by at least one actuator (52) for controlling the position of the connecting member (58) relative to the surface (44).   5. Method according to claim 4, characterized in that the or each actuator (52) controls the position of the or each connecting member (58) in a direction substantially perpendicular to the surface (44).   6. Method according to one of claims 4 or 5, characterized in that the or each actuator (52) is a linear actuator.