Frontgassack

Abstract

Front gasbag, comprising a front wall (18) facing the occupant, an opposite rear wall (20) and an upper wall (22) connecting the front and rear walls (18, 20), and a retaining strap system (34) attached to the front wall (18), wherein an active actuating device (30) for controlled release of a first retaining strap (32) is provided, characterized in that the first or a further, second retaining strap (32, 42) is folded and the fold (46) is held by a tear seam (48), wherein the tear seam (48) is arranged such that it can only be subjected to tensile stress and tears after activation of the actuating device (30).

Description

[0001] The invention relates to a front gasbag with a front wall facing an occupant, an opposite rear wall and an upper wall connecting the front and rear walls, and a restraint strap system attached to the front wall, wherein an active actuating device for controlled release of the first restraint strap is provided.

[0002] Front airbags 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 its vertical axis. When inflating, the airbag initially moves very strongly towards the occupant in the X direction and then retracts back to its original position.

[0003] Furthermore, there are front airbags that can be configured with two different contours: one with a large volume and one with a slightly smaller volume. Depending on the accident situation, the occupant's position in the vehicle, or their physical condition, the larger or smaller geometry is required. For this purpose, a retaining strap system is provided inside the airbag, as well as an active confirmation device for the controlled release of the first retaining strap.

[0004] The object of the invention is to further improve such a known front airbag in such a way that the front airbag can be deployed better and, in addition, the pendulum movement in both the X and Z directions is reduced.

[0005] In a front gas bag of the type mentioned above, this is achieved by folding the first retaining strap or a further, second retaining strap and holding the fold with a tear seam, the tear seam being arranged in such a way that it can only be subjected to tensile stress and tear after the actuating device has been activated.

[0006] Without activation of the release mechanism, the first retaining strap is active and holds the airbag in its smaller form. When the release mechanism is activated, the rupture seam is stressed, and the first retaining strap temporarily holds the airbag back until the rupture seam tears, allowing the inflation process to temporarily follow different directions. If the still-intact rupture seam temporarily restrains the inflation towards the occupant until it tears, sections of the airbag can expand in the Y and Z directions during this period of restraint. This reduces excessively rapid inflation in the X direction, which in turn reduces oscillation in the X direction. Furthermore, the airbag volume is available sooner in the Y and Z directions, further reducing oscillation in the Z direction. Energy can also be absorbed when the rupture seam breaks.

[0007] In one embodiment of the invention, the retaining strap system can have a second retaining strap equipped with a folding mechanism. This second retaining strap then determines the final, larger inflated geometry of the gas bag. This larger geometry can be achieved after the actuating device is activated.

[0008] Depending on the design, the pendulum movement of the gas bag in the X-direction after the tear seam has opened can also be limited by the length of the first or the further, second retaining strap.

[0009] The actuating device can be housed in a gas bag module casing, so that the gas bag module with gas bag and gas generator represents, for example, a completely pre-assembled unit that can be inserted into the instrument panel.

[0010] In order to be able to predetermine the contour of the front wall within narrow limits, a distributor catch band arrangement can be attached to the front wall, to which the first and, if present, the second catch band are attached inside the gasbag.

[0011] The distributor safety strap assembly can, for example, have a V-shaped safety strap structure when the gas bag is inflated, which is attached to the vertical upper and lower sections of the front wall. The first safety strap and, if present, the second safety strap are coupled to the inner end of the safety strap structure, with, for example, one of the safety straps being attached directly to the inner end and the other safety strap being attached to the first one. Alternatively, both safety straps are attached directly to the safety strap structure.

[0012] If only the first retaining strap is present, it may have a fold between a module-side attachment point and the actuating mechanism. This means that when the front gas bag is to assume its compact shape, the actuating mechanism is not activated, and the fold is not under tension. Only the portion of the first retaining strap that runs between the actuating mechanism and the front wall is under tension.

[0013] The actuating device can be an anchor for the first safety strap or can actively release an anchor for the first safety strap.

[0014] According to one embodiment of the invention, the first retaining strap and, if present, the second retaining strap can extend directly from the front wall or indirectly from the V-shaped retaining strap structure inside the gasbag to the gasbag module, or, in an alternative embodiment, via a deflection at the upper wall to the gasbag module or to the rear wall, where it is attached either to the gasbag module or to the rear wall. This deflection allows for the targeted absorption of forces in specific directions, which, when the front gasbag is inflated, dampens the unfolding movement in certain directions. This reduces pendulum movements.

[0015] Further features and advantages of the invention will become apparent from the following description and from the following drawings, to which reference is made. The drawings show: Fig. 1 A schematic cross-sectional view of a front gasbag in inflated state with a small contour, Fig. 2 the front gasbag to Fig. 1 with a larger outline, Fig. 3 a second embodiment of the front gasbag according to the invention in an inflated state with a small contour, Fig. 4. the front gasbag Fig. 3 in inflated state with large contour, Fig. 5 a third embodiment of the front gasbag according to the invention in the inflated state with a small contour, Fig. 6. the front gasbag Fig. 5 with large contour, Fig. 7 a fourth embodiment of the front gasbag according to the invention in the inflated state with a small contour, and Fig. 8 the front gasbag to Fig. 7 with a large outline.

[0016] In Fig. Figure 1 shows a front airbag 10, which is part of an airbag module 12 housed in the instrument panel 14 of a vehicle. When inflated, the airbag 10 can partially rest against the windshield 16, but this is optional.

[0017] The gasbag 10 shown has a front wall 18 facing the occupant and an opposite rear wall 20 as well as a so-called upper wall 22, which connects the front wall 18 and the rear wall 20.

[0018] A gas generator 24 inside the gasbag module 12 is used to inflate the gasbag 10.

[0019] The gas generator 24 can be a single-stage gas generator or a multi-stage gas generator.

[0020] Inside the gas bag 10, a retaining strap system 26 is provided, by means of which the gas bag 10 can assume two forms, namely the one described in Fig. 1. Smaller figure shown with a smaller volume (contour) and the one in Fig. 2 Larger shape shown with a larger gasbag volume (contour).

[0021] Depending on factors such as the occupant's position or the nature of the impact, the occupant may be positioned in either direction. Fig. 1 shown shape with smaller volume and the one in Fig. The shape shown in section 2 can be assumed with a larger volume.

[0022] A control unit 28 ensures that, depending on one or more of the above parameters or other parameters, one or the other gasbag shape is achieved.

[0023] The safety belt system includes an active actuation device 30 housed in the gas bag module 12, which is, for example, an electrically activatable pyrotechnic device and which can be controlled via the control unit 28.

[0024] This active actuating device 30, for example, releases or leaves the module-side anchorage of a first retaining strap 32 unreleased. The first retaining strap 32 extends forward from the module to the front wall 18 and is attached there to a so-called distributor retaining strap assembly 34. The distributor retaining strap assembly 34 comprises a V-shaped retaining strap structure with an upper end 36 and a lower end 38, to which the retaining strap structure is attached to the front wall 18, and an inner end 40 of the "V", in the area of ​​which the first retaining strap 32 is attached. The attachment of the first retaining strap 32 to the distributor retaining strap assembly 40 is permanent.

[0025] A second safety strap 42 is attached to the distributor safety strap assembly 40 or directly in the area of ​​the attachment of the first safety strap 32 to the distributor safety strap assembly 40, which is attached at the opposite end 44, for example on the module side, here in the area of ​​the gas generator 24, although this is only an example.

[0026] The second retaining strap 42 includes a fold 46, here inside the gas bag 10, which is temporarily fixed by one or more tear seams 48.

[0027] Should the front gasbag 10 be in the smaller shape according to Fig. When the first retaining strap 32 is inflated, the actuating device 30 remains deactivated, meaning that the anchoring of the module-side end of the first retaining strap 32 is maintained. The first retaining strap 32 absorbs all forces exerted on it via the moving front wall 18.

[0028] The length of the second retaining strap 42 is chosen, despite the fold 46, such that when the first retaining strap 32 is taut, the tear seam 48 is not stressed or at least so little stressed that the tear seam 48 does not break.

[0029] However, should the in Fig. To achieve the larger contour shown in section 2, the actuating device 30 is activated via the control unit 28. The module-side end of the retaining strap 32 is released. Then the second retaining strap 32 is, as shown in Fig. Figure 2 shows that the second retaining strap 42 is not under tensile stress, and the entire tensile force acts on it. The forces introduced into the second retaining strap 42 are too great for the tear seam 48, which consequently breaks. The second retaining strap 42 is longer than the first retaining strap 32, so the larger contour according to Fig. 2 is achieved. However, during unfolding, the temporarily intact tear seam causes the unfolding to be directed in different directions than without the tear seam 48.

[0030] This reduces the oscillation in the X and Z directions. The oscillation in the X direction is further reduced or limited by the length of the second retaining strap 42.

[0031] The following embodiments show variations of the embodiments according to the Fig. 1 and Fig. 2, so that in the following the reference symbols already introduced for identical or functionally equivalent parts are retained and only the differences are discussed.

[0032] In the embodiment according to Fig. 3 There is only one first retaining strap 32, which is, however, divided into two sections. A first section extends from the distributor retaining strap assembly 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 module-side attachment 44, which here, for example, can also be provided in the area of ​​the gas generator 24.

[0033] If the front airbag 10 is to assume the smaller contour, only the first section of the retaining strap 32 is subjected to tensile stress; here too, the actuating device 30 is not activated. The fold 46 remains unloaded.

[0034] However, if the confirmation device 30 is activated, the tensile force of the first section of the retaining strap 32 is immediately introduced into the fold 46 and the tear seam 48, causing it to break, as shown in Fig. 4 shown. The gasbag can take on the larger contour.

[0035] The variant according to Fig. 5 essentially corresponds to the one after Fig. 1. However, the second retaining strap 42 is deflected in the area of ​​the upper wall 22, for example, by the upper wall 22 having a loop 60, or by a loop 60 being attached to the upper wall 22 through which the second retaining strap 42 extends. Here too, the second retaining strap 42 is naturally not under tension as long as the actuating device 30 is not activated. Only after activation of the actuating device 30, when the first retaining strap 32 releases, see also Fig. 6, the second retaining strap 42 takes over the restraint of the front wall 18, so that the tear seam 48 is destroyed.

[0036] In the illustrated embodiment, the deflection 60 remains active when the gas bag 18 is fully deployed.

[0037] The embodiment according to Fig. 7 essentially corresponds to the one after Fig. 1, however, the second retaining strap 42 is not attached to the module side, but to a reinforcement layer 64 inside 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 wall of the gas bag, i.e., to the upper wall 22 and / or the rear wall 20, either over its entire surface or at several points, for example, via seams. The retaining strap 42 is preferably connected only to the reinforcement layer 64 via the seam 66, so that tensile forces of the retaining strap 42 do not act directly on the outer wall of the gas bag. However, it is also possible for the retaining strap 42 to be connected via the seam 66 to both the reinforcement layer 64 and the outer wall of the gas bag in the area of ​​the upper wall 22 and / or the rear wall 20.

[0038] Otherwise, this embodiment is functionally similar to or identical with embodiment 1.

Claims

[1] Front gasbag, comprising a front wall (18) facing the occupant, a rear wall (20) opposite, and an upper wall (22) connecting the front and rear walls (18, 20), and a retaining strap system (34) attached to the front wall (18), wherein an active actuating device (30) for controlled release of a first retaining strap (32) is provided, characterized by , that the first or a further, second retaining strap (32, 42) is folded and the fold (46) is held by a tear seam (48), wherein the tear seam (48) is arranged such that it can only be subjected to tensile stress and tear after activation of the actuating device (30). [2] Front gasbag according to claim 1, characterized by , that the retaining strap system (34) has a second retaining strap (42) equipped with the folding (46) and the second retaining strap (42) determines the final geometry of the inflated gas bag (10) when the actuating device (30) is activated. [3] Front gasbag according to claim 1 or 2, characterized by , that the actuating device (30) is housed in a gasbag module (12) [4] Front gasbag according to one of the preceding claims, characterized by , that a distributor securing strap arrangement (34) is attached to the front wall (18), to which the first and, if present, the second securing strap (32, 42) are attached inside the gas bag. [5] Front gasbag according to claim 4, characterized by , that the distributor catch band arrangement (34) is a V-shaped catch band structure which is attached to vertically upper and lower areas (36, 38) of the front wall (18) and at the inner end (40) of which the first catch band (32) and, if present, the second catch band (42) are coupled. [6] Front gasbag according to one of the preceding claims, characterized by, that only the first retaining strap (32) is present and that this has the fold (46) which is located between a module-side attachment point (44) and the actuating device (30). [7] Front gasbag according to one of claims 1 to 5, characterized by , that a second retaining strap (42) is present and this has the fold (46), wherein when the actuating device (30) is not activated the second retaining strap (42) is not under tension, so that the first retaining strap (32) alone determines the inflated geometry of the gas bag (10). [8] Front gasbag according to one of the preceding claims, characterized by , that the first and, if present, the second retaining strap (32, 42) is coupled directly or indirectly to the front wall (18) at its front end and extends to the gasbag module (12). [9] Front gasbag according to any one of claims 1 to 7, characterized by, that the first and, if present, the second retaining strap (32, 42) is directly or indirectly coupled to the front wall (18) and runs via a deflection (60) on the upper wall (22) to the gasbag module (12) or to the rear wall (20). [10] Front gasbag according to any one of claims 1 to 7, characterized by , that the first and, if present, the second retaining strap (32, 42) are coupled directly or indirectly to the front wall (18) and are attached at the opposite end to a reinforcement layer (64) provided on the upper wall (22).

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