FR3148405A1 - Guiding device for deploying a vehicle airbag comprising an elongated hinge - Google Patents

Abstract

Guiding device for deploying a vehicle airbag comprising an elongated hinge The guiding device (1) comprises a housing (2) comprising a first transverse wall (6) and a second transverse wall (8) and two longitudinal walls (10), said transverse and longitudinal walls (6, 8, 10) defining an internal volume (12), the guiding device comprising at least a first flap (4) connected to the first transverse wall (6) by a first hinge (22), said first flap (4) being movable relative to said first transverse wall (6) between a closed position and an open position, the first transverse wall (6), the first flap (4) and the first hinge (22) being integral. The first hinge (22) has a length, measured in the transverse direction (T), which is at least 90% of the length of the first flap (4). Figure for abstract: 1

Description

Guiding device for deploying a vehicle airbag comprising an elongated hinge

The present invention relates to a guiding device for deploying a vehicle airbag, of the type comprising a housing comprising a first transverse wall and a second transverse wall extending in a transverse direction and two longitudinal walls extending in a longitudinal direction, substantially perpendicular to the transverse direction, on each side of the first and second transverse walls, said longitudinal walls joining the first transverse wall to the second transverse wall, said transverse and longitudinal walls defining an internal volume for receiving an airbag during its deployment, the housing defining an upper opening for the passage of the deployed airbag, the guiding device further comprising at least a first flap connected to the first transverse wall by a first hinge, said first flap being movable relative to said first transverse wall between a closed position, in which the first flap closes at least part of the upper opening, and an open position, in which the first flap releases at least part of the passage for the deployed airbag, the first flap extending in the transverse direction from one longitudinal wall to the other longitudinal wall, the first transverse wall, the first shutter and the first hinge being made of material.

The invention applies for example to an airbag module installed in a trim element, such as a dashboard, and more particularly a foam trim element, in which a foam is added to the guide device of the airbag module.

In a known manner, such a guide device, also known as a firing channel, is arranged to guide the airbag towards the vehicle passenger compartment through the foam of the trim element when the airbag inflates and deploys. To do this, the guide device comprises a housing receiving the airbag and forming a channel for guiding the deployment of the airbag through an upper opening of the housing. The upper opening is closed by one or two flaps which are moved by the airbag to an open position during deployment of the airbag, the flaps being arranged to tear the foam covering the guide device in order to free a passage for the airbag. The flaps are therefore articulated to walls of the housing to be movable relative to the housing between the closed position and the open position.

When the filling element is to be foamed onto the guide device to form a padding element of the filling element, the upper opening of the housing must be sealed in order to prevent the foam from entering the channel defined by the housing during the foaming operation of the filling element. For this purpose, it is known to make the walls of the housing, the hinges and the flaps in one piece so that the upper opening is sealed.

However, in this case, the hinge is at risk of breaking when the airbag is deployed because the hinge does not have sufficient strength to withstand the deployment of the airbag. This is because in order to allow the flaps to rotate, the hinge must be straight and flexible, with the straight portion of the hinge being limited by the shape of the firing channel, making it more fragile.

One of the aims of the invention is to overcome this drawback by proposing a guide device, in which the hinge is made in one piece with the rest of the guide device while being capable of resisting the deployment of the airbag.

For this purpose, the invention relates to a guide device of the aforementioned type, in which the first hinge has a length, measured in the transverse direction, which is at least 90% of the length of the first flap measured in the transverse direction.

By increasing the length of the hinge between the longitudinal walls, the hinge has a length close to the theoretical maximum length that this hinge can have and the resistance of the hinge is increased so that the hinge allows the flap to move between the closed position and the open position without breaking during deployment of the airbag.

The guidance device according to the invention may comprise the following characteristics, considered alone or in any technically conceivable combination:

- the first hinge comprises a projecting portion extending in the longitudinal direction in the internal volume of the housing;

- the first hinge comprises a straight portion extending between the projecting portion and the first flap, said straight portion being substantially coplanar with a lower portion of the first transverse wall;

- the projecting portion has a U-shaped section, a lower branch of the U extending from a base of the U to the lower portion of the first transverse wall and an upper branch of the U extending from the base of the U to the straight portion, the lower and upper branches being spaced from each other in an elevation direction substantially perpendicular to the transverse and longitudinal directions;

- the first hinge is connected to each longitudinal wall by an upper corner, said upper corner having a radius of curvature less than the radius of curvature of a lower corner extending between a lower portion of the first transverse wall and each longitudinal wall;

- the first flap is fixed in the closed position to the two longitudinal walls by breakable tabs, said longitudinal walls, said breakable tabs and the first flap being made in one piece, said breakable tabs being arranged to tear when the first flap moves from the closed position to the open position;

- the housing comprises an upper peripheral wall extending around the upper opening, said peripheral wall extending substantially perpendicular to the first and second transverse walls and to the longitudinal walls;

- the housing comprises at least one rib extending between the first transverse wall and the upper peripheral wall, said rib extending outside the internal volume, said rib being integral with the first hinge;

- the first flap is connected to the upper peripheral wall by a weakened portion, said weakened portion allowing the movement of the first flap relative to the upper peripheral wall between the closed position and the open position, said first flap, said weakened portion and said upper peripheral wall being made in one piece;

- the guide device further comprises a second flap connected to the second transverse wall by a second hinge, said second flap being movable relative to said second transverse wall between a closed position, in which the second flap closes the upper opening with the first flap, and an open position, in which the second flap releases with the first flap the passage for the deployed airbag, the second flap extending in the transverse direction from one longitudinal wall to the other longitudinal wall and the second transverse wall, the second flap and the second hinge being integral, the second hinge having a length, measured in the transverse direction, which is at least 90% of the length of the second flap measured in the transverse direction.

Other aspects and advantages of the invention will appear on reading the following description, given by way of example and with reference to the appended drawings, in which:

- there is a schematic perspective representation of a guide device according to the invention, the shutters being in the closed position,

- there is a longitudinal sectional representation along the II-II axis of the ,

- there is a partial cross-sectional representation along the III-III axis of the , And

- there is a schematic perspective representation of part of the guidance device of the .

Referring to Figs. 1 and 2, a guide device 1 comprising a housing 2 and at least one first flap 4 is described.

The housing 2 comprises a first transverse wall 6, a second transverse wall 8 and two longitudinal walls 10 defining between them an internal volume 12. The first and second walls 6, 8 extend in a transverse direction T and on each side of the internal volume 12 in a longitudinal direction L substantially perpendicular to the transverse direction T. The longitudinal walls 10 extend in a longitudinal direction L and on each side of the internal volume 12 in the transverse direction T. The longitudinal walls 10 connect the first transverse wall 6 to the second transverse wall 8, at each end of the first and second transverse walls 6, 8 in the transverse direction T.

When the guide device 1 is installed in a vehicle dashboard, the transverse direction corresponds for example to the width of the vehicle and the longitudinal direction corresponds to the front-rear direction of the vehicle.

In an elevation direction Z, substantially perpendicular to the transverse and longitudinal directions, the first and second transverse walls 6, 8 and the longitudinal walls 10 each extend between a lower end 14 and an upper end 16. The elevation direction Z corresponds for example to the height of the vehicle when the guidance device 1 is installed in a vehicle dashboard. The upper ends 16 of the first and second transverse walls 6, 8 and the longitudinal walls 10 together define an upper opening 18 of the housing 2.

The housing 2 is arranged to guide a vehicle airbag during its deployment, the airbag being inflated in the internal volume 12 and being guided towards the passenger compartment of the vehicle through the upper opening 18 of the housing 2. In other words, the upper opening 18 forms a passage for the airbag deployed towards the outside of the trim element in which the guide device 1 is installed.

The first flap 4 is arranged to close at least a portion of the upper opening 18 in a closed position of the first flap 4, as shown in the . As shown in Figs. 1 and 2, according to one embodiment, the upper opening is further closed by a second flap 20, as will be described in more detail later.

In the closed position, the first flap 4 extends in the transverse direction T from one longitudinal wall 10 to the other longitudinal wall 10. The length of the first flap 4 is defined as the dimension of the first flap 4 in the transverse direction T from one longitudinal wall 10 to the other.

The first flap 4 is movable relative to the housing 2 between the closed position and an open position (not shown), in which the first flap 4 is moved away from the upper opening 18 in order to free at least a portion of the passage for the airbag. In other words, in the closed position, the first flap 4 extends over at least a portion of the upper opening 18, i.e., the first flap 4 extends primarily in the longitudinal and transverse directions, and in the open position, the first flap 4 is moved away from the upper opening 18 after being lifted in the elevation direction by the deploying airbag. The movement of the first flap 4 between the closed position and the open position is a rotation relative to the housing 2 about an axis of rotation extending in the transverse direction T.

For this purpose, the first flap 4 is connected to the first transverse wall 6 by a first hinge 22 arranged to allow the rotation of the first flap 4 relative to the first transverse wall 6 between the closed and open positions. The first transverse wall 6, the first hinge 22 and the first flap 4 are integral, that is to say they are made from a single piece of the same material. More particularly, the first hinge 22 forms a portion of the upper part of the first transverse wall 6 and a portion of the upper end 16 of the first transverse wall 6 is a part of the first hinge 22.

According to one embodiment, the entire guiding device 1 is made of one piece, that is to say that the walls of the housing 2 and the flaps 4, 20 are made of a single piece of the same material. For this purpose, the first flap 4 is for example fixed to the longitudinal walls 10 by breakable tabs 24, shown in the , when the first flap 4 is in the closed position. These breakable tabs 24 extend on each side of the first flap 4 in the transverse direction T between the first flap 4 and each of the longitudinal walls 10 and are integral with the first flap 4 and the longitudinal walls 10. Consequently, when the first flap 4 is in the closed position, the breakable tabs 24 leave no space between the first flap 4 and the longitudinal walls 10 so that the part of the upper opening 18 over which the first flap 4 extends is sealed. The breakable tabs 24 are arranged to tear during deployment of the airbag during deployment of the airbag in order to allow the first flap 4 to move relative to the housing between the closed position and the open position. In other words, the breakable tabs 24 are destroyed when the airbag pushes on the first flap 4 to release the first flap 4 from the longitudinal walls 10 and allow the first flap 4 to move to the open position. The breakable tabs 24 are for example formed of weakened portions extending between the edges of the first flap 4 and the longitudinal walls 10. Such weakened portions have for example a thickness, measured in the elevation direction Z, which is less than the thickness of the first flap 4 so that the breakable tabs 24 are more fragile than the first flap 4 and tend to tear when the first flap 4 is pushed in the elevation direction Z by the inflation of the airbag during deployment of the airbag.

Such a guide device 1 is for example produced by injection molding in a single piece.

The first hinge 22 has a length, measured in the transverse direction T, which is at least 90% of the length of the first flap 4. In other words, the ends of the first hinge 22 in the transverse direction T are arranged very close to the longitudinal walls 10 so that the first hinge 22 forms most of the upper portion of the first transverse wall 6 in the transverse direction T. According to one embodiment, the first hinge 22 has a length which is at least 95% of the length of the first flap 4. This length of the first hinge 22 makes it possible to have a robust first hinge 22 while allowing the movement of the first flap 4 between the closed position and the open position, as will be described in more detail later.

It should be noted that, in the prior art, the length of the hinge is reduced because the transverse wall is connected to the longitudinal walls 10 by rounded corners. Indeed, the use of rounded corners makes it possible to improve the behavior of the first flap 4 during deployment of the airbag, in particular by improving the control of the tearing of the breakable tabs 24. The presence of rounded corners is not compatible with a hinge extending practically from one longitudinal wall 10 to the other and the length of the hinge must be reduced to take into account the radius of curvature of the rounded corners. Such a hinge with a reduced length is not satisfactory because its robustness is reduced so that the hinge risks breaking during deployment of the airbag due to the force applied to the flap by the inflation of the airbag. Indeed, the hinge generally has a length which is at most 70% of the length of the corresponding flap.

In addition, "ears" must be provided on the flap on each side of the hinge in the transverse direction to bridge the distance between the transverse ends of the hinge and the longitudinal walls. These ears tend to be caught by the airbag during deployment, increasing the risk of hinge failure.

In order to solve these problems and to allow the length of the first hinge 22 to be increased, the first hinge 22 is connected to each longitudinal wall 10 by an upper corner 26, shown in the , which has a radius of curvature that is less than the radius of curvature of a lower corner 28 extending between a lower portion 30 of the first transverse wall 6 and each longitudinal wall 10. The lower portion 30 of the first transverse wall 6 is defined as the portion of the first transverse wall 6 extending between the lower end 14 of the first transverse wall 6 and the first hinge 22 in the elevation direction. In this way, the length of the first hinge 22 can be increased because the upper corners 26 are less “rounded” than the lower corners 28 while preserving satisfactory behavior of the first flap 4 during deployment of the airbag thanks to the more “rounded” lower corners 28. The radius of curvature of each upper corner 26 is arranged such that the length of the first hinge 22 is at least 90%, preferably at least 95%, of the length of the first flap 4. According to one embodiment, the upper corner 26 is close to a right-angle corner between the first transverse wall 6 and each longitudinal wall 10 or is a right-angle corner, as will be described later.

According to the embodiment shown in the figures, the first hinge 22 comprises a projecting portion 32 extending in projection from the first transverse wall 6 in the longitudinal direction L inside the internal volume 12. In other words, the projecting portion 32 reduces the dimension of the internal volume 12, in the vicinity of the upper opening 18, in the longitudinal direction L, as more particularly visible in the .

The protruding portion 32 makes it possible to increase the dimension of the first hinge 22 in the elevation direction Z and to increase the flexibility of the hinge without reducing its robustness. Furthermore, the protruding portion 32 forms a deflector for the airbag during its deployment which guides the airbag towards the end of the first flap 4, opposite the end of the first flap 4 fixed to the first hinge 22. In this way, the force exerted by the airbag on the first flap 4 is applied where it is most effective in moving the first flap 4 between the closed and open positions and less towards the first hinge 22, which reduces the forces exerted on the first hinge 22 and reduces the risks of breakage of the first hinge 22.

As more particularly visible in Figs. 2 and 4, the projecting portion 32 has for example a U-shaped section, comprising a lower branch 34 extending from the base 36 of the U to the lower portion 30 of the first transverse wall 6 and an upper branch 38 extending from the base 36 to a straight portion 40 of the first hinge 22, the straight portion 40 extending between the projecting portion 32 and the first flap 4. The straight portion 40 thus defines the upper end 16 of the first transverse wall 6. The straight portion 40 extends for example substantially in the same plane as the lower portion 30 of the first transverse wall 6. The lower branch 34 and the upper branch 38 are spaced apart from each other in the elevation direction Z.

According to the embodiment shown in the , the upper corner 26 changes from a right-angled corner between the straight portion 40 and each longitudinal wall 10 to a more rounded corner between the lower branch 36 and each longitudinal wall 10.

As previously indicated, according to the embodiment shown in Figs. 1 and 2, the guide device 1 comprises a second flap 20, closing the upper opening 18 with the first flap 4 in the closed position. The second flap 20 is fixed to the second transverse wall 8 by a second hinge 42 and is also movable between the closed position and an open position. The second hinge 42 is of a similar structure as that of the first hinge 22 and will not be described in further detail here. By “of similar structure” it is understood that the second hinge 42 also has a length which is at least 90% of the length of the second transverse wall 8, preferably at least 95%. The second hinge 42 for example also comprises a U-shaped protruding portion 32, with a base 36, a lower branch 34 and an upper branch 38. Consequently, the second hinge 42 also acts as a deflector for the airbag guiding the deployment of the airbag towards the connection between the first flap 4 and the second flap 20.

Since the guide device is integral and since the upper opening 18 is closed in a sealed manner when the first and second flaps 4, 20 are in the closed position, the first flap 4 and the second flap 20 are connected to each other by a breakable portion 44, for example extending substantially in the center of the upper opening 18 in the longitudinal direction L, as shown in the figure. . The breakable portion 44 is arranged to be torn by the airbag during deployment of the airbag such that the first flap 4 and the second flap 20 are separated from each other and can move from the closed position to the open position independently of each other. Such a breakable portion 44 is for example formed by a portion of material having a reduced thickness compared to the thickness of the first and second flaps 4, 20. It should be noted that the projecting portions 32 of the first and second hinges 22, 42 are arranged to guide the deployment of the airbag towards the breakable portion 44 such that the force exerted by the airbag is concentrated around the breakable portion 44. Consequently, the tearing of the breakable portion 44 by the airbag is particularly effective.

According to the embodiment shown in the figures, the guide device 1 further comprises an upper peripheral wall 46 extending around the upper opening 18. The peripheral wall 46 extends substantially perpendicular to the first and second transverse walls 6, 8 and to the longitudinal walls 10. As shown in Figs. 1 and 2, the peripheral wall 46 extends substantially in the same plane as the first flap 4 (and the second flap 20 when such a flap is provided). Such a peripheral wall 46 is arranged to be placed on the edges of an opening provided in a support of a trim element for receiving the guide device 1. The peripheral wall 46 makes it possible to close this opening in a sealed manner so that the support of the trim element and the guide device 1 can be foamed together to form a foam padding on the support and the guide device 1. Since the upper opening 18 of the guide device 1 and the opening in the support are sealed, the foam cannot enter the internal volume 12 of the guide device 1 or around the guide device in the opening of the support during this operation.

The first flap 4 and, if provided, the second flap 20 are connected to the upper peripheral wall 46 by a weakened portion 48, for example formed by a reduced thickness of material between the upper peripheral wall 46 and the first flap 4 and the second flap 20. The weakened portions 48 are arranged to allow the movement of the first flap 4 and the second flap 20 relative to the upper peripheral wall 46 between the closed position and the open position. As previously described, the first flap 4, the second flap 20, the weakened portions 48 and the upper peripheral wall are integral.

According to one embodiment, the guide device 1 further comprises at least one rib 50 extending between the first transverse wall 6 and the upper peripheral wall 46. This rib 50 extends outside the internal volume 12 and extends into the projecting portion 32 of the first hinge 22, as shown in the . This rib 50 is integral with the first transverse wall 6, including the first hinge 22, and makes it possible to stiffen the first transverse wall 6 without preventing the movement of the first flap 4 relative to the first transverse wall 6 thanks to the first hinge 22. According to one embodiment, several ribs 50 are provided, these ribs being spaced from each other in the transverse direction T. At least one rib can also be provided on the second transverse wall 8 outside the interior volume 12.

The guide device 1 described above may be made of a single piece that can be foamed with the remainder of the trim element in which the guide device 1 is installed. The length of the hinges allows for efficient opening of the corresponding flaps while the hinges have a reduced risk of breakage during deployment of the airbag.

Claims (10)

A guiding device (1) for deploying a vehicle airbag comprising a housing (2) comprising a first transverse wall (6) and a second transverse wall (8) extending in a transverse direction (T) and two longitudinal walls (10) extending in a longitudinal direction (L), substantially perpendicular to the transverse direction (T), on each side of the first and second transverse walls (6, 8), said longitudinal walls (10) joining the first transverse wall (6) to the second transverse wall (8), said transverse and longitudinal walls (6, 8, 10) defining an internal volume (12) for receiving an airbag during its deployment, the housing (2) defining an upper opening (18) for the passage of the deployed airbag, the guiding device further comprising at least one first flap (4) connected to the first transverse wall (6) by a first hinge (22), said first flap (4) being movable relative to said first transverse wall (6) between a closed position, in which the first flap (4) closes at least part of the upper opening (18), and an open position, in which the first flap (4) releases at least part of the passage for the deployed airbag, the first flap (4) extending in the transverse direction (T) from one longitudinal wall (10) to the other longitudinal wall (10), the first transverse wall (6), the first flap (4) and the first hinge (22) being integral, characterized in that the first hinge (22) has a length, measured in the transverse direction (T), which is at least 90% of the length of the first flap (4) measured in the transverse direction (T). Guiding device according to claim 1, wherein the first hinge (22) comprises a projecting portion (32) extending in the longitudinal direction (L) in the internal volume (12) of the housing (2). A guiding device according to claim 2, wherein the first hinge (22) comprises a straight portion (40) extending between the projecting portion (32) and the first flap (4), said straight portion (40) being substantially coplanar with a lower portion (30) of the first transverse wall (6). A guiding device according to claim 3, wherein the projecting portion (32) has a U-shaped section, a lower branch (34) of the U extending from a base (36) of the U to the lower portion (30) of the first transverse wall (6) and an upper branch (38) of the U extending from the base (36) of the U to the straight portion (40), the lower and upper branches (34, 38) being spaced from each other in an elevation direction (Z) substantially perpendicular to the transverse and longitudinal directions. A guiding device according to any one of claims 1 to 4, wherein the first hinge (22) is connected to each longitudinal wall (10) by an upper corner (26), said upper corner (26) having a radius of curvature less than the radius of curvature of a lower corner (28) extending between a lower portion (30) of the first transverse wall (6) and each longitudinal wall (10). A guiding device according to any one of claims 1 to 5, wherein the first flap (4) is fixed in the closed position to the two longitudinal walls (10) by breakable tabs (24), said longitudinal walls (10), said breakable tabs (24) and the first flap (4) being integral, said breakable tabs (24) being arranged to tear when the first flap (4) moves from the closed position to the open position. A guiding device according to any one of claims 1 to 6, wherein the housing (2) comprises an upper peripheral wall (46) extending around the upper opening (18), said peripheral wall (46) extending substantially perpendicular to the first and second transverse walls (6, 8) and to the longitudinal walls (10). Guiding device according to claim 7, wherein the housing (2) comprises at least one rib (50) extending between the first transverse wall (6) and the upper peripheral wall (46), said rib (50) extending outside the internal volume (12), said rib (50) being integral with the first hinge (22). A guiding device according to claim 7 or 8, wherein the first flap (4) is connected to the upper peripheral wall (46) by a weakened portion (48), said weakened portion (48) allowing movement of the first flap (4) relative to the upper peripheral wall (46) between the closed position and the open position, said first flap (4), said weakened portion (48) and said upper peripheral wall (46) being integral. A guiding device according to any one of claims 1 to 9, further comprising a second flap (20) connected to the second transverse wall (8) by a second hinge (42), said second flap (20) being movable relative to said second transverse wall (8) between a closed position, in which the second flap (20) closes with the first flap (4) the upper opening (18), and an open position, in which the second flap (20) releases with the first flap (4) the passage for the deployed airbag, the second flap (20) extending in the transverse direction (T) from one longitudinal wall (10) to the other longitudinal wall (10) and the second transverse wall (8), the second flap (20) and the second hinge (42) being integral, the second hinge (42) having a length, measured in the transverse direction (T), which is at least 90% of the length of the second flap (20) measured in the transverse direction (T).