WO2020127541A1

WO2020127541A1 - Front airbag

Info

Publication number: WO2020127541A1
Application number: PCT/EP2019/086030
Authority: WO
Inventors: Werner Freisler; Simon Schmid; Reiner Dannenhauer; Sven Tamme; Pawel MALCZAK
Original assignee: Trw Automotive Gmbh
Priority date: 2018-12-20
Filing date: 2019-12-18
Publication date: 2020-06-25
Also published as: DE102018133050A1

Abstract

A front airbag (10) has a front wall (18) facing the occupant, an opposite rear wall (20), and an upper wall (22). An active actuation device (30) for releasing a first tether (32) of a tether system (34) is provided, and a fold (46) is retained by a tearable seam (48) which is subjected to stress only upon activation of the actuation device (30).

Description

Front gas bag

The invention relates to a front gas bag with a front wall facing an occupant, an opposite rear wall and an upper wall connecting the front and rear walls, and a tether system which is fastened to the front wall, an active actuating device being provided for the controlled release of the first tether is.

Front gas bags have a very large inflation volume and can tend to oscillate in the X and Y directions. The X direction is the vehicle's longitudinal axis and the Z direction is the vehicle's vertical axis. In the X direction, the airbag first moves very strongly towards the occupant when it is unfolded, and then pulls back into its actual position.

There are also front gas bags in which two different contours can be achieved, namely a contour with a large volume and a contour with a somewhat smaller volume. Depending on the accident situation or the position of the occupant in the vehicle or on the constitution of the occupant, the large or small geometry is desired. For this purpose, a tether system is provided in the interior of the gas bag, as is an active confirmation device for the controlled release of the first tether.

The object of the invention is to further improve such a known front airbag in such a way that the front airbag can be better deployed on the one hand and the oscillation is reduced both in the X and in the Z direction. This is achieved in a front airbag of the type mentioned in that the first tether or a further, second tether is folded and the fold is held with a tear seam, the tear seam being arranged in such a way that it is not subjected to tension until the actuating device is activated can and tears.

Without activation of the actuation device, the first tether is active and keeps the gas bag in its smaller shape. If the actuation device is activated, the tear seam is loaded and the first tether holds the gas bag temporarily until the tear seam tears, so that the unfolding process can temporarily have different directions of deployment. If the unfolding towards the occupant is temporarily held back by the still intact tear seam, namely until it tears, sections of the gas bag can unfold in the Y and Z directions during this holding back. On the one hand, this reduces the rapid deployment in the X direction, which in turn reduces the swinging in the X direction, and on the other hand the gas bag volume in the Y and Z directions is available earlier, which further reduces the swinging movement in the Z direction . Energy can also be absorbed by tearing the tear seam.

In a variant of the invention, the tether system can have a second tether which is equipped with the folding. The second tether then determines the finally inflated, larger geometry of the gas bag. This larger geometry can be achieved after the actuator is activated.

Depending on the embodiment, an oscillation of the gas bag in the X direction after the tear seam has been torn open can be limited by the length of the first or the further, second tether.

The actuating device can be accommodated in a gas bag module housing, so that the gas bag module with gas bag and gas generator represents, for example, a completely preassembled unit which can be inserted into the dashboard.

In order to be able to predetermine the contour of the front wall within narrow limits, a distributor tether arrangement can be attached to the front wall which the first and, if available, the second tether are fastened inside the airbag.

The distributor tether arrangement can, for example, have a V-shaped tether structure in the inflated state of the gas bag, which is attached to vertically upper and lower regions of the front wall. The first tether and, if present, the second tether is coupled to the inner end of the tether structure, e.g. one of the tether is attached directly to the inner end and the other tether is attached to the aforementioned tether. Alternatively, both tether straps are attached directly to the tether structure.

If only the first tether is present, it can have a fold that is present between a module-side fastening point and the actuating device. This means that if the front airbag is to take on its small shape, the actuating device is not activated and the folding is not stressed. Only that part of the first tether that is between the actuating device and the front wall is subjected to tension.

The actuating device can be an anchor for the first tether or can actively release an anchor for the first tether.

According to a variant of the invention, the first tether and, if present, the second tether can extend in the interior of the gas bag directly from the front wall or from the V-shaped tether structure indirectly to the gas bag module or, in an alternative variant, via a deflection on the upper wall Airbag module or to the rear wall, where it is either attached to the airbag module or to the rear wall. This deflection allows forces to be absorbed in specific directions, which, when the front gas bag is inflated, dampen the unfolding movement in certain directions. This reduces pendulum movements.

Further features and advantages of the invention result from the following description and from the following drawings, to which reference is made. The drawings show:

FIG. 1 shows a schematic cross-sectional view of a front gas bag in the inflated state with a small contour, FIG. 2 shows the front airbag according to FIG. 1 with a larger contour,

FIG. 3 shows a second embodiment of the front gas bag according to the invention in the inflated state with a small contour,

FIG. 4 shows the front airbag according to FIG. 3 in the inflated state with a large contour,

FIG. 5 shows a third embodiment of the front gas bag according to the invention in the inflated state with a small contour,

FIG. 6 shows the front airbag according to FIG. 5 with a large contour,

Figure 7 shows a fourth embodiment of the front gas bag according to the invention in the inflated state with a small contour, and

8 shows the front airbag according to FIG. 7 with a large contour.

FIG. 1 shows a front airbag 10 which is part of an airbag module 12 which is accommodated in the dashboard 14 of a vehicle. In the inflated state, the gas bag 10 can be partially supported on the windscreen 16, but this is only optionally the case.

The gas bag 10 shown has a front wall 18 which faces the occupant, and an opposite rear wall 20 and a so-called upper wall 22 which connects the front wall 18 and the rear wall 20 to one another.

A gas generator 24 in the interior of the gas bag module 12 serves to inflate the gas bag 10.

The gas generator 24 can be a single-stage gas generator or a multi-stage gas generator.

In the interior of the gas bag 10, a tether system 26 is provided, via which the gas bag 10 can assume two shapes, namely the smaller shape shown in FIG. 1 with a smaller volume (contour) and the larger shape shown in FIG. 2 with a larger gas bag volume (contour ).

Depending on how, for example, the occupant is positioned or on what the impact situation is, the shape shown in FIG smaller volume and the shape shown in Figure 2 with a larger volume.

A controller 28 ensures that one or the other gas bag shape is achieved depending on one or more of the above parameters or other parameters.

The tether system comprises an active actuating device 30 accommodated in the gas bag module 12, which is, for example, an electrically activatable pyrotechnic device and which can be controlled via the control 28.

For example, the module-side anchoring of a first fan band 32 is released or not released via this active actuating device 30. The first tether 32 extends from the module forward to the front wall 18 and is attached there to a so-called distributor tether arrangement 34. The distributor tether arrangement 34 comprises a V-shaped tether structure with an upper end 36 and a lower end 38, to which the tether structure is attached to the front wall 18, and an inner end 40 of the “V”, in the area of which the first tether 32 is attached . The attachment of the first tether 32 to the distributor tether assembly 40 is permanent.

A second tether 42 is fastened to the distributor tether arrangement 40 or directly in the region of the attachment of the first tether 32 to the distributor tether arrangement 40, which is fastened at the opposite end 44, for example on the module side, here in the region of the gas generator 24, this being only an example.

The second tether 42 includes a fold 46, here in the interior of the gas bag 10, which is temporarily fixed by one or more tear seams 48.

If the front airbag 10 is to be inflated in the smaller shape according to FIG. 1, the actuating device 30 does not remain activated, that is to say the anchoring of the module-side end of the first tether 32 is retained. The first tether 32 absorbs all forces which are exerted on the first tether 32 via the moving front wall 18. Despite the fold 46, the length of the second tether 42 is selected such that when the first tether 32 is taut, the tear seam 48 is not loaded or is at least so slightly loaded that the tear seam 48 does not break.

On the other hand, if the larger contour shown in FIG. 2 is to be achieved, the actuating device 30 is activated via the control 28. The module-side end of the tether 32 is released. Then, as shown in FIG. 2, the second tether 32 is not subjected to tensile stress and the entire train acts on the second tether 42. The forces introduced into the second tether 42 are too great for the tear seam 48, which breaks as a result. The second tether 42 is longer than the first tether 32, so that the larger contour according to FIG. 2 is achieved. During the deployment, however, the temporarily intact tear seam leads to the fact that the deployment is directed in different directions than without the tear seam 48.

This reduces oscillation in the X and Z directions. The oscillation in the X direction is also reduced or limited by the length of the second tether 42.

The following embodiments show modifications of the embodiments according to FIGS. 1 and 2, so that the reference symbols already introduced for identical or functionally identical parts are retained in the following and only the differences are discussed.

In the embodiment according to FIG. 3 there is only a first tether 32, which is however divided into two sections. A first section extends from the distributor tether arrangement 40 to the actuating device 30. A second section 50, which is provided with the fold 46, which in turn is temporarily fixed by one or more tear seams 48, extends from the actuating device 30 to the fastening 44 on the module side , which can also be provided here, for example, in the area of the gas generator 24.

If the front airbag 10 is to assume the smaller contour, only the first section of the tether 32 is subjected to tension; here, too, the actuating device 30 is not activated. The fold 46 remains unloaded. However, if the confirmation device 30 is activated, the tensile force of the first section of the tether 32 is immediately introduced into the fold 46 and the tear seam 48, so that it breaks, as shown in FIG. The gas bag can take on the larger contour.

The variant according to FIG. 5 essentially corresponds to that according to FIG. 1, but the second tether 42 is deflected in the region of the upper wall 22, for example by the upper wall 22 having a loop 60, or a loop 60 being attached to the upper wall 22, through which the second tether 42 extends. Here, too, of course, the second tether 42 is not under tension as long as the actuating device 30 is not activated. Only after activation of the actuating device 30, when the first tether 32 releases, see also FIG. 6, does the second tether 42 hold back the front wall 18, so that the tear seam 48 is destroyed.

In the embodiment shown, the deflection 60 remains active when the gas bag 18 is fully deployed.

The embodiment according to FIG. 7 essentially corresponds to that according to FIG. 1, but here the second tether 42 is not fastened on the module side, but on a reinforcement layer 64 in the interior of the gas bag, specifically in the area of the upper wall 22, via a permanently stable seam 66 The reinforcement layer 64 can be attached to the outer surface of the airbag, that is to say to the upper wall 22 and / or to the rear wall 20, in a flat manner or in several places, for example by means of seams. The tether 42 is preferably only connected to the reinforcement layer 64 via the seam 66, so that tensile forces of the tether 42 do not act directly on the gas bag outer wall. However, it can also be provided that the tether 42 is connected via the seam 66 both to the reinforcement layer 64 and to the gas bag outer wall in the region of the upper wall 22 and / or the rear wall 20.

Otherwise, this embodiment is functionally similar to embodiment 1 or identical to it.

Claims

1. Front gas bag, with a front wall facing the occupant (18), an opposite rear wall (20) and an upper wall (22), which connects the front and rear walls (18, 20), and a tether system (34) connected to the Front wall (18) is fastened, an active actuating device (30) for the controlled release of a first tether (32) being present, characterized in that the first or a further, second tether (32, 42) is folded and the fold (46) is held with a tear seam (48), the tear seam (48) being arranged in such a way that it can only be subjected to tension and tear after the activation of the actuating device (30).

2. Front airbag according to claim 1, characterized in that the tether system (34) has a fold (46) equipped with the second tether (42) and the second tether (42) determines the final geometry of the inflated gas bag (10) when the Actuator (30) is activated.

3. Front airbag according to claim 1 or 2, characterized in that the actuating device (30) is housed in an airbag module (12)

4. Front airbag according to one of the preceding claims, characterized in that a distributor tether arrangement (34) on the front wall

(18) is attached to which the first and, if present, the second tether (32, 42) are fastened in the interior of the gas bag.

5. Front airbag according to claim 4, characterized in that the distributor tether arrangement is a V-shaped tether structure which is attached to vertically upper and lower regions (36, 38) of the front wall (18) and at the inner end (40) of the first tether (32) and, if available, the second tether (42) are coupled.

6. Front airbag according to one of the preceding claims, characterized in that only the first tether (32) is present and this has the fold (46) which is present between a module-side fastening point (44) and the actuating device (30).

7. Front gas bag according to one of claims 1 to 5, characterized in that a second tether (42) is present and this has the fold (46), wherein the second tether (42) is not loaded on train when the actuating device (30) is not activated , so that the first tether (32) alone determines the inflated geometry of the gas bag (10).

8. Front airbag according to one of the preceding claims, characterized in that the first and, if present, the second tether (32, 42) is coupled with the front end directly or indirectly to the front wall (18) and to the gas bag module (12) extends. 9. Front airbag according to one of claims 1 to 7, characterized in that the first and, if present, the second tether (32, 42) is directly or indirectly coupled to the front wall (18) and via a deflection (60) on the top wall (22) to the gas bag module (12) or to the rear wall (20). 10. Front airbag according to one of claims 1 to 7, characterized in that the first and, if present, the second tether (32, 42) are directly or indirectly coupled to the front wall (18) and with the opposite end at one of the Top wall (22) provided reinforcing layer (64) are attached.