Gasbag with active ventilation system

Abstract

A gasbag with an active ventilation device is described. The gasbag has a first outer shell that encloses a first gas space. A first layer (10) of this first outer shell has an inner surface (10b) facing the first gas space and an outer surface (10a) facing away from the first gas space. The active ventilation device comprises an opening (14) in the first layer (10) and a cover element (52) arranged on the outer surface (10a) of the first layer (10). The cover element (52) at least partially covers the opening (14) and is permanently connected to the first layer (10) by means of a cover element connection (62). The cover element connection (62) is not closed, so that an opening area exists between the first layer (10) and the cover element (52).Furthermore, the active ventilation device comprises an expansion assembly with a second shell (42) enclosing a second gas space (47) and a gas generator. The second shell (62) is arranged on the inner surface (10b) of the first layer (10) and overlaps the cover element (52) at least partially. A further element of the active ventilation assembly is a tear seam (66) which has a section extending through the cover element (52), the first layer (10), and the second shell (42), thus preventing or restricting gas escape through the opening area in a first state of the ventilation device.

Description

[0001] The invention relates to a gas bag with an active ventilation device according to claim 1 and to a gas bag unit with such a gas bag and a main inflator according to claim 12.

[0002] Each airbag, which serves to protect a vehicle occupant in the event of an accident, has an outer shell (hereinafter also referred to as the first shell) which encloses a first gas space. This first shell has at least one first layer, which has an inner surface facing the first gas space and an outer surface facing away from the first gas space.

[0003] It is known to equip such a gas bag with an active ventilation device that has a throttled or closed first state and an open second state. The first layer has an opening through which gas can escape, at least in the second state.

[0004] Such a gas bag with a ventilation device is known from the generic document DE 10 2012 016 460 B4. Here, a grommet extending around the opening and connected to the first envelope is provided, from which a tension element extends. The end of this tension element facing away from the grommet is connected by means of a tear seam to a second envelope ("microbag"), which can be filled by means of a gas generator in such a way that the tear seam tears. The first envelope and the associated gas generator form an expansion assembly. If the first envelope is fully inflated but the second envelope is not, the tension element is under tensile stress and holds the grommet inside the first gas space in a contracted state, so that the ventilation device is in a throttled first state. If the gas generator is ignited, the second envelope expands and the tear seam tears.This releases the second end of the tear seam, the grommet turns outwards due to the gas pressure in the first gas space and the ventilation device is in its open second state.

[0005] A disadvantage of this state of the art is that there is a certain time delay between the activation of the gas generator of the expansion element and the complete achievement of the second state, since the nozzle must first turn outwards.

[0006] Based on this, the present invention has the object of providing a gas bag with an alternatively designed ventilation device in which, in particular, a very short time delay can be achieved between the ignition of the gas generator of the expansion element and the complete achievement of the second state.

[0007] This object is achieved by a gas bag having the features of claim 1. A gas bag unit with such a gas bag and a main inflator is specified in claim 12.

[0008] The gas bag according to the invention has a cover element arranged on the outer surface of the first layer, firmly connected to the first layer, which covers the opening at least partially, preferably completely. The connection between the first layer and the cover element is achieved by means of a cover element connection, which is not closed, thus creating an opening area between the first layer and the cover element. For this purpose, the cover element connection can be U-shaped, in particular.

[0009] As with the gas bag of the generic DE 10 2012 016 460 B4, an expansion assembly is provided with a second shell enclosing a second gas space and a gas generator. However, this expansion assembly does not serve to hold and release a tension element, but rather directly influences the state of the perforation and the state of the cover element. For this purpose, the second shell is arranged on the inside of the first layer and overlaps the cover element at least in sections, in particular in the opening area. Furthermore, a tear seam is also provided in the gas bag according to the invention. This has a section that extends through the cover element, the first layer, and the second shell. The tear seam blocks gas outflow through the opening area at least partially, preferably completely, and holds the ventilation device in its first state, in which it can in particular also be completely tightly closed.

[0010] When the gas generator is ignited, the tear seam tears due to the expanding first shell and the opening area is released, so that gas from the first gas space can flow through the opening into the area between the first layer and the cover element and from there escape through the now open opening area.

[0011] The ventilation device according to the invention has the following particular advantages: Due to the arrangement of the second shell and the tear seam, the time delay between actuation of the gas generator and the occurrence of the second state is very short. This also means that the ventilation device has virtually no undefined intermediate state between the first state and the second state, resulting in highly reproducible behavior. Finally, both a completely closed first state and a second state with a large opening cross-section, i.e., strong ventilation, can be realized.

[0012] Preferably, the opening has at least one slot-shaped section or is designed to be slot-shaped overall. This allows, in particular, the pressure existing between the first layer and the cover element in the first state to be kept low and the cover element to be relieved of stress.

[0013] To increase the free cross-section in the second state, it may be preferable for the cover element to be folded in the first state and, at least in sections, to be formed with at least three layers. In the second state, the cover element unfolds, so that the free cross-section between the cover element and the first layer increases, at least in the opening area.

[0014] In a first preferred embodiment, the first (outer) shell of the gas bag further comprises a second layer, and the ventilation device is arranged in a region of an edge of the first layer, i.e., where the two layers meet. Furthermore, the opening extends to the edge of the first layer, and the first layer is permanently connected to the second layer along its edge by means of an edge connection, wherein at least the region of the ventilation device in which the opening ends at the edge, preferably the entire opening region, is free of a permanent connection. The tear seam crosses the opening. Such a gas bag is easy to manufacture and, in particular, allows a large ventilation cross-section in the second state, even when the opening is slit-shaped.

[0015] As a rule, it is advantageous if, in the embodiment just described, the gas generator of the expansion assembly is arranged outside the first gas space. Therefore, it is preferred that a portion of the second shell protrudes from the edge of the first shell, so that this portion is located outside the first gas space. To simplify assembly, the second layer can have a bulge located outside the first gas space such that the portion of the second shell and the bulge overlap at least in sections.

[0016] Also to simplify assembly, the second shell may be connected to the second layer by means of an assembly connection which exclusively connects the second shell and the second layer of the first shell.

[0017] In a second preferred embodiment, the ventilation device is located in a region of the first layer spaced from the edge, and the second layer is not involved in the ventilation device. In this case, it is particularly advantageous to design the opening in the first layer in a T-, V-, or U-shape.

[0018] In order not to hinder the expansion of the second shell, it is preferred that only the tear seam extends through the second gas space.

[0019] Preferably, at least one layer of the second shell is designed to be gas-permeable, so that after expansion of the second shell and the resulting at least partial tearing of the tear seam, the gas escapes from the second shell. This prevents the expanded second shell from obstructing the gas outflow in the second state of the ventilation device. Gas permeability can be achieved, for example, through microperforation.

[0020] The invention will now be described in more detail using preferred embodiments with reference to the figures. Herein: Fig. 1 all components (except seams) of a first embodiment of a gas bag unit in a schematic representation, Fig. 2 the detail D1 from Fig. 1 in an enlarged representation, but in a view from the back related to Fig. 1, Fig. 3 the detail D2 from Fig. 1, Fig. 4 the detail D3 from Fig. 1, namely a second shell and a gas generator, Fig. 4a a section along the plane AA in Fig. 4, Fig. 4b one expansion assembly, which consists of the second shell and the gas generator of the Fig. 4 exists, Fig. 5 the detail D4 from Fig. 1, namely the cut for a cover element, Fig. 6 which results from the cutting of the Fig. 5 folded cover element, Fig. 6a a side view of the cover element of the Fig. 6 from direction R in Fig. 6, Fig. 7 the in Fig. 2 shown section of the second layer of the first shell and the Fig. 4b shown expansion assembly, which is attached to the first shell by means of an assembly seam, Fig. 8 the in Fig. 3 shown section of the first layer of the first shell and the Fig. 6 shown folded cover element, which is attached to the first cover by means of a cover element seam, Fig. 9 that in Fig. 7 Shown and that in Fig. 8 Shown, after folding the first cover along its fold line, Fig. 10 that in Fig. 9 Shown after attaching sections of the edge seam, Fig. 11 that in Fig. 10 Shown, after applying a tear seam, Fig. 12 that in Fig. 11 Shown, with hidden elements not shown, Fig. 13 a highly schematic representation of the layer structure of the ventilation device, Fig. 14 the ventilation device in one of the Fig. 12 corresponding representation after actuation of the gas generator of the expansion element, Fig. 15 that in Fig. 13 Shown in the state after actuation of the gas generator (corresponding to the state of the Fig. 14), Fig. 16 all components (except seams) of a second embodiment of a gas bag unit in a schematic representation, Fig. 17 the detail D5 from Fig. 16, Fig. 18 the in Fig. 17 shown section of the first layer of the first shell and the Fig. 6 shown folded cover element, which is attached by means of a cover element seam on the outer surface of the first shell, Fig. 19 that in Fig. 18 and the expansion unit arranged on the inner surface of the first layer of the first shell, Fig. 20 that in Fig. 19 Shown after arranging the tear seam, Fig. 21 that in Fig. 20 Shown, but hidden elements are not shown, and Fig. 22 an alternative design of the tear seam in one of the Fig. 21 corresponding representation, Fig. 23 all components (except seams) of a variation of the second embodiment of a gas bag unit in a schematic representation according to Fig. 16, Fig. 24 the detail D6 from Fig. 23, Fig. 25 that in Fig. 24 and the detail shown in Fig. 23 shown cover element, which is sewn to the first layer in the folded state and covers the opening (according to Fig. 8), Fig. 26 that in Fig. 25 and the expansion assembly arranged on the inner surface of the first layer, Fig. 27 that in Fig. 26 Shown after arranging the assembly seam and the tear seam (according Fig. 20), Fig. 28 that in Fig. 27 Shown, but without showing the expansion module and Fig. 29 that in Fig. 28 shown, with an alternative design of the tear seam.

[0021] The invention will now be described using exemplary embodiments of an airbag unit. This airbag unit comprises an airbag and a main inflator. In the described exemplary embodiment, the airbag is a simple side airbag in terms of its basic structure, whose outer shell (hereinafter: first shell) has only two layers (so-called 2D airbag). However, this is to be understood only as an example. The invention can in principle be applied to any airbag or airbag unit. The only essential requirement is that the airbag has an actively controllable ventilation device.

[0022] To better understand the structure of the airbag according to the invention, in particular its ventilation device, the manufacture of the airbag from its components will first be described. Only the components absolutely necessary for this exemplary embodiment of the invention are illustrated and described, but of course, an airbag according to the invention can also have additional components (such as inner or outer safety straps or the like). However, to keep the illustration simple, such additional (optional) components are not illustrated or described.

[0023] The Fig. Figure 1 shows all components of a side airbag unit according to the invention, i.e., the components of the airbag (except for connections, in particular seams) and the main inflator 30. Like any other airbag, the airbag has a first shell (which could also be referred to as an outer shell) that encloses a first gas chamber. The main inflator 30 serves to fill this first gas chamber.

[0024] In the illustrated embodiment, the first cover (outer cover) has two layers 10, 20, which are created from a common blank 5' by folding along the fold line F (so-called butterfly design). However, this is not mandatory for the invention. The two layers could also be made from separate blanks.

[0025] In the illustrated embodiment of the first embodiment, the ventilation device is located in an edge region where the two layers are connected. Arranging the ventilation device away from such an edge region would be possible, but is generally not preferred.

[0026] Having said this, we will now first examine the Fig. 1 described components: The common blank 5' of the first cover has a first section for the first layer 10 and a second section for the second layer 20. These two sections are folded onto one another along the fold line F to form the first cover, as is of course known in the art. As mentioned, separate blanks could also originally have been provided for the two layers. The first layer 10 has (of course) an outer surface 10a and an inner surface 10b. Inner surface here means that in the fully assembled gas bag, this inner surface 10b faces at least in sections towards the first gas space, which is enclosed by the outer cover. The same naturally also applies to the second layer 20, which has an inner surface 20b facing at least in sections towards the gas space, and an outer surface 20a. In the Fig. In the state of the first shell shown in Figure 1, one looks at the outer surfaces 10a, 20a of the two layers 10, 20.

[0027] In the area of ​​an edge (in the embodiment shown in the area of ​​the edge opposite the fold line F), the first layer 10 has a slit-shaped opening 14, which extends to the edge (Detail D2 - Fig. 3). The first end (inner end) 14a of the slot-shaped opening 14 facing away from the edge is widened and essentially circular in shape. Compared to the just-described area of ​​the first layer 10, the second layer 20 has a bulge 22 in the edge area (Detail D1 - Fig. 2). The slot 14 and the bulge 22 are components of the active ventilation device according to the invention.

[0028] In Fig. 1 are also the components of an expansion module 40 (Detail D3 - Fig. 4) and a cut 50 of a cover element (Detail D4 - Fig. 5) shows which are the essential components of the ventilation system and which are now to be considered with regard to the Fig. 4 to 4b, or 5 to 6a, are described in more detail: The Fig. 4 shows the detail D3 of the Fig. 1, namely the components of an expansion assembly. These are a second shell 42, which encloses a second gas space 47, and an associated gas generator 48 for filling this second gas space. Such an expansion element 40 is described in detail, for example, in WO 2014 / 029 473 A1. The second shell 42 (often referred to as a "microbag") has a first layer 43 and a second layer 44 in the region of the second gas space 47, and these two layers are connected to one another in an edge region 46 (see in particular Fig. 4a). Preferably, the second shell 42 is manufactured using a one-piece woven process. Further preferably, at least one of the two layers of the second shell, here the first layer 43, has a gas-permeable ventilation region 43a, so that after the second gas space 47 has been filled, gas can escape from it again. The edge region 46 is preferably relatively wide, since—as will be seen later—seams are arranged that extend through this edge region 46, but not through the second gas space 47.

[0029] As is known in the art, the gas generator 48 projects through an opening in the second shell into the latter ( Fig. 4b), so that when ignited, it fills the second gas chamber. The gas generator is usually designed as a pyrotechnic ignition element ("squib").

[0030] Fig. 5 shows detail D4 from Fig. 1, namely the blank 50 of a cover element of the ventilation device. In Fig. 5 dashed folding lines are drawn along which the blank 50 is folded to the cover element 52 (see Fig. 6 and Fig. 6a). Due to the folding, the folded cover element 52 is formed in sections with at least three layers ( Fig. 6a).

[0031] The assembly of the gas bag 5 is now described. The main inflator is generally only installed on or in the first shell once the gas bag assembly is complete. This is not shown here.

[0032] As in Fig. As shown in Figure 7, in an assembly step, the expansion assembly 40—namely its second shell 42—is fastened in the region of the bulge 22 to the inner surface 20b of the second layer 20 by means of an assembly seam 60. The assembly seam 60 extends exclusively through the edge region 46 of the second shell, not through the second gas space 47. This assembly seam primarily serves as a pre-fixation and could be replaced by an alternative joining technique, for example, adhesive bonding.

[0033] The folded cover element 52 is arranged on the outer surface 10a of the first layer 10 such that the slit-shaped opening 14 is completely covered and an edge region of the folded cover element 52 is flush with the edge region of the first layer 10 at which the slit-shaped opening 14 ends. The U-shaped cover element seam 62, which serves as a cover element connection, serves for fastening. The side legs 62a, 62b of the U extend outwardly of the fold lines, and the transverse leg 63c of the U extends—naturally—across the entire width of the folded cover element. Thus, the cover element is held in its folded form by the cover element seam (namely by the transverse leg 63c), but can still unfold. In the area of ​​the edge, the cover element is not connected to the first layer by the cover element seam 63, so that an opening area O is created.

[0034] In the next production step (see Fig. 9), the blank 5' of the first sleeve 5 is folded along the fold line so that the first layer 10 and the second layer 20 lie on top of each other. As a result, the slit-shaped opening 14 now lies partially on the expansion element 40.

[0035] In the next step, an edge seam 64 is applied, which serves as an edge connection and connects the edges of the two layers 10, 20 to each other, thus enclosing the first gas space (in the illustrated embodiment together with the fold line F). It is important that the edge seam does not cross the opening 14 and does not close the opening area O, which is achieved in the illustrated embodiment by the edge seam 64 having two sections 64a and 64b, which also extend through the edge area 46 of the second envelope. Furthermore, the edge seam 64 should not run through the second gas space 47. The state after application of the edge seam 64 is shown in Fig. 10 shown.

[0036] In the final step ( Fig. 11), a tear seam 66 is arranged, which intersects the two sections 64a and 64b of the edge seam and the two side legs 62a, 62b of the cover element seam 62, thereby closing the opening area O, so that gas cannot flow from the first gas space via the space between the first layer and the cover element through the opening area. The tear seam 66 also extends through the second gas space 47.

[0037] This results in a layer structure which is shown schematically in the Fig. 13 is shown: Between the first layer 10 and the second layer 20 there is the second cover 42, which is also partially two-layered, and on the outer surface 10a of the first layer 10 there is the cover element 52, which is partially three-layered. It is important through which layers the seams just described extend: Only the tear seam 66 extends through all layers and also crosses the second gas space 47. The cover element seam 62 connects exclusively the outer edge of the cover element 52 with the first layer 10, whereby it should be noted (this is in Fig. 13 not shown), the transverse leg 62c of the U-shaped cover element seam 62 extends through all layers of the cover element. The sections of the edge seam 64 extend through both layers 10, 20 and the edge region 46 of the second shell 42. The assembly seam connects the edge region of the second shell 42 to the second layer 20.

[0038] If the gas generator is ignited, the second shell 42 expands and the tear seam is destroyed in the area of ​​the second shell 42. This releases the opening area O, the originally slit-shaped opening 14 gapes open, the cover element 52 bulges up and gas can flow out of the first gas space through this opening and the opening area ( Fig. 14 and Fig. 15).

[0039] The Fig. Figures 16 to 21 show an exemplary embodiment of a second embodiment of the invention. The difference from the first embodiment is that the active ventilation device is not located in an edge region of the first layer and, in particular, does not extend to the edge.

[0040] How to Fig. 16, the second embodiment consists of the same components as the first embodiment, only the opening in the first layer is designed and positioned differently, as can be seen, for example, in the Fig. 16 and Fig. 17 takes: As in the first embodiment, the opening has a first slot-shaped section 14 extending from a first end 14a. However, this first slot-shaped section 14 does not extend to the edge, but rather ends at a second end 14b. From there, a second slot-shaped section 15 extends—preferably perpendicularly—so that the opening is T-shaped. The second slot-shaped section "replaces" (with respect to the ventilation device) the open edge region of the first embodiment.

[0041] As in Fig. As can be seen in Figure 18, first, as in the first exemplary embodiment, the folded cover element 52 is arranged by means of the cover element seam 62 on the outer surface 10 of the first layer 10 such that it covers the first slit-shaped section 14. The front end of the cover element 52 is essentially aligned with the second slit-shaped section 15 of the opening.

[0042] The expansion assembly 40 is then arranged on the inner surface of the first layer 10, with its second sleeve 42 being able to be attached to the first layer with an assembly seam 60. Compared to the first embodiment, the inflator-side end of the expansion assembly is further away from the opening (moved to the right in the selected illustrations).

[0043] Finally, the tear seam 66 is arranged, which (as in the first embodiment) extends through the first slit-shaped section 14. Due to the absence of the edge seam in the area of ​​the ventilation device, the tear seam 66 completely surrounds the second slit-shaped area 15 and is located within the second shell 42 in order to separate the second slit-shaped area 15 from the first gas space. Fig. 22 shows an alternative design of the tear seam 66, which is designed here as a zigzag seam and with which the second slit-shaped section 15 is directly sewn.

[0044] In the second embodiment, the second layer of the first cover is not involved in the ventilation device, so that the folding of the common blank and the arrangement of the edge seam only take place after the ventilation device has been manufactured.

[0045] The Fig. Figures 23 to 29 show a variation of the second embodiment. The differences are in the shape of the opening and in the shape and number of folds of the cover element 52. For example, Fig. As can be seen from Figure 24, the opening here also has two slit-shaped sections 14 and 15, but these do not form a T, but rather a V, which also allows for gaping. In this context, it should be mentioned that other opening shapes are also possible, for example, a U-shape.

[0046] How to Fig. 25, the cover element 52 follows the V-shape of the opening by reducing its width towards the tip of the V (i.e. towards the opening area O). As shown in the Fig. As can be seen in Figure 27, the assembly seam 60 and the tear seam can be made as in the execution of the Fig. 20 trained. Fig. 29 shows a variant of this.

[0047] The functionality is the same as in the first embodiment.

[0048] The exemplary embodiments just described demonstrate all the advantages of the ventilation device design according to the invention: It is easy to manufacture and, upon activation of the gas generator, transitions almost instantly from its first state to its second state. Furthermore, a completely sealed first state and a strongly ventilating second state can be realized. List of reference symbols 5 first cover 5` joint cutting of the first cover 10 first layer 10a outer surface of the first layer 10b inner surface of the first layer 12 Outer layer of the first layer 14 slot-shaped opening in the first layer / first slot-shaped section of the opening in the first layer 14a inner end of the slot-shaped opening / first end of the first slot-shaped section 14b second end of the first slot-shaped section 15 second slot-shaped section of the opening 20 second layer 20a outer surface of the second layer 20b inner surface of the second layer 22 Bulge of the second layer 30 Main inflator 40 Expansion module 42 second shell 43 first layer of the second shell 43a Ventilation area 44 second layer of the second shell 46 Edge area of ​​the second shell 47 second gas chamber 48 Gas generator of the expansion element 50 Cutting the cover element 52 Cover element 60 assembly seam 62 Cover element seam 64 edge seam 66 Tear seam F fold line O Opening area QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 102012016460 B4 [0004, 0009] WO 2014 / 029473 A1

[0028]

Claims

[1] Gasbag with - a first shell (5) which encloses a first gas space and which has a first layer (10) which has an inner surface (10b) facing the first gas space and an outer surface (10a) facing away from the first gas space, and - an active ventilation device which has a throttled or closed first state and an open second state and which comprises: - an opening (14) in the first layer (10), - a cover element (52) arranged on the outer surface (10a) of the first layer (10), which cover element (52) covers the opening (14) at least in sections and which is permanently connected to the first layer (10) by means of a cover element connection (62), wherein the cover element connection (62) is not closed, so that an opening area (O) is created between the first layer (10) and the cover element (52), - an expansion assembly (40) with a second shell (42) enclosing a second gas space (47) and a gas generator (48), wherein the second shell (42) is arranged on the inner surface (10b) of the first layer (10) and overlaps the cover element (52) at least in sections, - a tear seam (66) which has a section which extends through the cover element (52), the first layer (10) and the second cover (42) and thus prevents or throttles gas escape through the opening area (O) in the first state of the ventilation device. [2] Gas bag according to claim 1, characterized by that the opening (14) has at least one slot-shaped section (14). [3] Gas bag according to claim 1 or claim 2, characterized by that the cover element (52) is folded and is formed at least in sections in at least three layers. [4] Gas bag according to one of claims 1 to 3, characterized by , that - the first shell (5) further comprises a second layer (20), - the ventilation device is arranged in a region of an edge of the first layer (10), - the opening (14) extends to the edge of the first layer (10), - the first layer (10) is permanently connected to the second layer (20) along its edge by means of an edge connection (64), wherein at least the region of the ventilation device in which the opening (14) ends at the edge is free of a permanent connection. [5] Gas bag according to claim 4, characterized by that a portion of the second shell (20) protrudes from the edge of the first shell so that this portion is located outside the first gas space. [6] Gas bag according to claim 5, characterized bythat the second layer (20) has a bulge (22) and that the section of the second shell (42) located outside the first gas space and the bulge (22) overlap at least in sections. [7] Gas bag according to one of claims 4 to 6, characterized by that the second shell (42) is connected to the second layer (20) by means of an assembly connection (60) which exclusively connects the second shell (42) and the second layer (20). [8] Gas bag according to one of claims 1 to 3, characterized by that the ventilation device is spaced from the edge of the first layer. [9] Gas bag according to claim 8, as far as it refers back to claim 3, characterized by that the opening is T-shaped or V-shaped with two slot-shaped sections (14, 15) or U-shaped. [10] Gas bag according to one of the preceding claims, characterized by that only the tear seam (66) extends through the second gas space (47). [11] Gas bag according to one of the preceding claims, characterized by that at least one layer (43) of the second casing is gas-permeable at least in sections. [12] Gas bag unit consisting of a gas bag according to one of claims 1 to 9 and a main inflator (30) for filling the first gas space.

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