Airbag having an active ventilation device
Patent Information
- Application Number
- EP2023809147
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-11-22
- Filing Date
- 2023-11-15
- Publication Date
- 2025-10-01
Smart Images
Figure 1.1
Abstract
Description
[0001] Gasbag with active ventilation device
[0002] Description
[0003] 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.
[0004] 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.
[0005] 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.
[0006] 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 chamber and the ventilation device is in its open second state.
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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.
[0011] 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 which 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.
[0012] 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.
[0013] 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.
[0014] The opening preferably has at least one slit-shaped section or is designed to be slit-shaped overall. This makes it possible, in particular, to keep the pressure prevailing between the first layer and the cover element in the first state low and to relieve the load on the cover element. A slit is a structure in which the opposing edges touch or at least almost touch, i.e. essentially no material is "missing" between the opposing edges. Significant gas passage can only occur when the slit opens up, which is what essentially distinguishes a slit from an elongated hole. In order to increase the free cross-section in the second state, it may be preferred for the cover element to be folded in the first state and, at least in sections, to be designed with at least three layers.In the second state, the cover element folds open so that the free cross-section between the cover element and the first layer increases, at least in the opening area.
[0015] 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.
[0016] 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.
[0017] Also to simplify assembly, the second shell can be connected to the second layer by means of an assembly connection that exclusively connects the second shell and the second layer of the first shell. 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:
[0021] Figure 1 shows all components (except seams) of a first embodiment of a gas bag unit in a schematic representation,
[0022] Figure 2 shows the detail D1 from Figure 1 in an enlarged view, but in a view from the back relative to Figure 1,
[0023] Figure 3 shows detail D2 from Figure 1,
[0024] Figure 4 shows the detail D3 of Figure 1, namely a second shell and a gas generator,
[0025] Figure 4a shows a section along the plane AA in Figure 4, Figure 4b shows an expansion assembly consisting of the second shell and the gas generator of Figure 4,
[0026] Figure 5 shows the detail D4 from Figure 1, namely the cut for a cover element,
[0027] Figure 6 shows the cover element folded from the blank in Figure 5,
[0028] Figure 6a is a side view of the cover element of Figure 6 from direction R in Figure 6,
[0029] Figure 7 shows the section of the second layer of the first shell shown in Figure 2 and the expansion assembly shown in Figure 4b, which is attached to the first shell by means of an assembly seam,
[0030] Figure 8 shows the section of the first layer of the first cover shown in Figure 3 and the folded cover element shown in Figure 6, which is attached to the first cover by means of a cover element seam,
[0031] Figure 9 shows what is shown in Figure 7 and what is shown in Figure 8, after folding the first envelope along its fold line,
[0032] Figure 10 shows what is shown in Figure 9 after sections of the edge seam have been applied,
[0033] Figure 11 shows what is shown in Figure 10, after applying a tear seam,
[0034] Figure 12 shows what is shown in Figure 11, with hidden elements not shown,
[0035] Figure 13 is a highly schematic representation of the layered structure of the ventilation device, Figure 14 is the ventilation device in a representation corresponding to Figure 12 after actuation of the gas generator of the expansion element,
[0036] Figure 15 shows what is shown in Figure 13 in the state after the gas generator has been activated (corresponding to the state of Figure 14),
[0037] Figure 16 shows all components (except seams) of a second embodiment of a gas bag unit in a schematic representation,
[0038] Figure 17 shows detail D5 from Figure 16,
[0039] Figure 18 shows the section of the first layer of the first cover shown in Figure 17 and the folded cover element shown in Figure 6, which is attached to the outer surface of the first cover by means of a cover element seam,
[0040] Figure 19 shows what is shown in Figure 18 and the expansion unit arranged on the inner surface of the first layer of the first shell,
[0041] Figure 20 shows what is shown in Figure 19 after arranging the tear seam,
[0042] Figure 21 shows what is shown in Figure 20, but concealed elements are not shown, and
[0043] Figure 22 shows an alternative design of the tear seam in a representation corresponding to Figure 21,
[0044] Figure 23 shows all components (except seams) of a variation of the second embodiment of a gas bag unit in a schematic representation according to Figure 16,
[0045] Figure 24 shows the detail D6 from Figure 23, Figure 25 shows the detail shown in Figure 24 as well as the cover element shown in Figure 23, which is sewn to the first layer in the folded state and covers the opening (corresponding to Figure 8),
[0046] Figure 26 shows what is shown in Figure 25 and the expansion assembly arranged on the inner surface of the first layer,
[0047] Figure 27 shows what is shown in Figure 26 after arranging the assembly seam and the tear seam (corresponding to Figure 20),
[0048] Figure 28 shows what is shown in Figure 27, but without showing the expansion module and
[0049] Figure 29 shows what is shown in Figure 28, with an alternative design of the tear seam.
[0050] 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.
[0051] 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.
[0052] 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 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.
[0053] 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.
[0054] 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.
[0055] Having said that, the components shown in Figure 1 will now be described:
[0056] The common blank 5' of the first shell 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 shell, as is of course known in the prior art. As mentioned, separate blanks could also originally have been provided for the two layers. The first layer 10 (of course) has 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 shell. 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 state of the first shell shown in Figure 1, one looks at the outer surfaces 10a, 20a of the two layers 10, 20.
[0057] In the area of an edge (in the illustrated embodiment, in the area of the edge opposite the fold line F), the first layer 10 has a slit-shaped opening 14 that extends to the edge (Detail D2 - Figure 3). The first end (inner end) 14a of the slit-shaped opening 14 facing away from the edge is widened and is essentially circular in shape. Compared to the area of the first layer 10 just described, the second layer 20 has a bulge 22 in the edge area (Detail D1 - Figure 2). The slit 14 and the bulge 22 are components of the active ventilation device according to the invention.
[0058] Figure 1 also shows the components of an expansion assembly 40 (Detail D3 - Figure 4) and a cut-out 50 of a cover element (Detail D4 - Figure 5), which are essential components of the ventilation device and which will now be described in more detail with reference to Figures 4 to 4b and 5 to 6a, respectively:
[0059] Figure 4 shows detail D3 of Figure 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 Figure 4a). The second shell 42 is preferably produced 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 which extend through this edge region 46, but not through the second gas space 47.
[0060] As is known in the prior art, the gas generator 48 extends through an opening in the second shell (Fig. 4b), so that upon ignition it fills the second gas chamber. The gas generator is usually designed in the form of a pyrotechnic ignition element ("squib").
[0061] Figure 5 shows detail D4 from Figure 1, namely the blank 50 of a cover element of the ventilation device. Figure 5 shows dashed fold lines along which the blank 50 is folded to form the folded cover element 52 (see Figures 6 and 6a). Due to the folding, the folded cover element 52 is formed in sections with at least three layers (Figure 6a).
[0062] 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.
[0063] 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, such as adhesive bonding.
[0064] 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.
[0065] In the next production step (see Figure 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.
[0066] In the next step, an edge seam 64 is applied, serving as an edge connection, which connects the edges of the two layers 10, 20 to one another and thus (in the illustrated embodiment, together with the fold line F) encloses the first gas space. 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 sleeve. 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 Figure 10.
[0067] In the final step (Figure 11), a tear seam 66 is arranged, which cuts the two sections 64a and 64b of the edge seam and the two side legs 62a, 62b of the cover element seam 62 and thereby closes 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. This results in a layered structure which is schematically illustrated in Figure 13: Between the first layer 10 and the second layer 20 is the second shell 42, which is also partially two-layered, and on the outer surface 10a of the first layer 10 is the cover element 52, which is partially three-layered. What is important is which layers the seams just described extend through: Only the tear seam 66 extends through all layers and also traverses the second gas space 47.The cover element seam 62 connects exclusively the outer edge of the cover element 52 to the first layer 10. However, it should be noted (this is not shown in Figure 13) that 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.
[0068] When the gas generator is ignited, the second shell 42 expands, and the tear seam is destroyed in the region of the second shell 42. This releases the opening area O, the originally slit-shaped aperture 14 gapes open, the cover element 52 bulges, and gas can flow out of the first gas space through this aperture and the opening area (Figures 14 and 15).
[0069] 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.
[0070] As can be seen from Figure 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 Figures 16 and 17:
[0071] 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.
[0072] As can be seen in Figure 18, as in the first embodiment, the folded cover element 52 is first 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.
[0073] 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).
[0074] 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 section 15 and is located within the second shell 42 to separate the second slit-shaped section 15 from the first gas space. Figure 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 shut.
[0075] In the second exemplary 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 produced. Figures 23 to 29 show a variation of the second exemplary embodiment. The differences lie in the shape of the opening and in the shape and number of folds of the cover element 52. As can be seen, for example, 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 shapes of the opening would of course be possible, for example a U-shape.
[0076] As can be seen from Figure 25, the cover element 52 follows the V-shape of the opening by reducing its width toward the tip of the V (i.e., toward the opening area O). As can be seen in Figure 27, the assembly seam 60 and the tear seam can be designed as in the embodiment of Figure 20. Figure 29 shows a variant of this.
[0077] The functionality is the same as in the first embodiment.
[0078] 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.
[0079] List of reference symbols
[0080] 5 first cover
[0081] 5' joint cutting of the first cover
[0082] 10 first layer
[0083] 10a outer surface of the first layer 0b inner surface of the first layer
[0084] 12 Outer layer of the first layer
[0085] 14 slot-shaped opening in the first layer / first slot-shaped section of the opening in the first layer
[0086] 14a inner end of the slot-shaped opening / first end of the first slot-shaped section
[0087] 14b second end of the first slot-shaped section
[0088] 15 second slot-shaped section of the opening
[0089] 20 second layer
[0090] 20a outer surface of the second layer
[0091] 20b inner surface of the second layer
[0092] 22 Bulge of the second layer
[0093] 30 Main inflator
[0094] 40 Expansion module
[0095] 42 second shell
[0096] 43 first layer of the second shell
[0097] 43a Ventilation area
[0098] 44 second layer of the second shell
[0099] 46 Edge area of the second shell
[0100] 47 second gas chamber
[0101] 48 Gas generator of the expansion element
[0102] 50 Cutting the cover element
[0103] 52 Cover element
[0104] 60 assembly seam
[0105] 62 Cover element seam
[0106] 64 edge seam
[0107] 66 Tear seam
[0108] F fold line
[0109] O Opening area
Claims
Patent claims 1. A gas bag comprising a first shell (5) enclosing a first gas space and comprising a first layer (10) having 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 having a throttled or closed first state and an open second state, and comprising: an opening (14) in the first layer (10), a cover element (52) arranged on the outer surface (10a) of the first layer (10), which 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, resulting in an opening region (O) 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 (62) 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 shell (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 in that the opening (14) has at least one slot-shaped section (14).
3. Gas bag according to claim 1 or claim 2, characterized in 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 in that the first cover (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 in that a portion of the second cover (20) protrudes from the edge of the first cover, so that this portion is located outside the first gas space.
6. Gas bag according to claim 5, characterized in that 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 in that the second cover (42) is connected to the second layer (20) by means of an assembly connection (60) which exclusively connects the second cover (42) and the second layer (20).
8. Gas bag according to one of claims 1 to 3, characterized in that the ventilation device is spaced from the edge of the first layer.
9. The gas bag according to claim 8, as far as dependent on claim 3, characterized in that the opening is T-shaped or V-shaped with two slit-shaped sections (14, 15) or U-shaped.
10. The gas bag according to one of the preceding claims, characterized in that only the tear seam (66) extends through the second gas chamber (47).
11. Gas bag according to one of the preceding claims, characterized in that at least one layer (43) of the second cover 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.