Vehicle occupant restraint system having air bag module

Abstract

The invention relates to a vehicle occupant restraint system, which comprises an airbag module (12), the airbag module comprising an airbag (16) and a gas generator (18), the gas generator providing filling gas for the airbag (16) when activated. The airbag (16) is assembled into an airbag package (14) before activation, so as to form a main package (48) and a connecting section (50), the main package comprising a restraining part (52) of the airbag (16) constituting a large part of the airbag volume, the connecting section comprising a neck (54) of the airbag (16), the neck connecting the restraining part (52) with the gas generator (18), wherein the restraining part (52) and the neck (54) are folded differently.

Description

Technical Field

[0001] The present invention relates to a vehicle occupant restraint system having an airbag module. Background Art

[0002] Airbags are used very successfully to protect vehicle occupants. They work best when the vehicle occupant to be accommodated is in a defined position relative to the inflated airbag. In the case of large-volume and complexly shaped airbags, it is necessary to ensure that they deploy accurately and reproducibly in the vehicle passenger compartment. Summary of the invention

[0003] It is therefore an object of the present invention to improve the deployment performance of an airbag.

[0004] This object is achieved with a vehicle occupant restraint system according to the invention. The vehicle occupant restraint system comprises an airbag module, which comprises an airbag and a gas generator, which provides filling gas for the airbag when activated, wherein the airbag is assembled into an airbag package before activation, namely a main package and a connecting section, wherein the main package comprises a restraining part of the airbag which constitutes the majority of the airbag volume, and the connecting section comprises a neck of the airbag which connects the restraining part to the gas generator, wherein the restraining part and the connecting section are folded differently. Such a division of the different sections of the airbag into different package sections allows the neck to be filled first when the gas generator is activated, and the neck then pushes the main package into the vehicle cabin while it is still at least partially folded. As a result, it can be moved into the vehicle cabin before the main package is fully unfolded and the airbag does not come into unintentional contact with panelling or other components in the vehicle cabin.

[0005] The neck is advantageously folded into one to three zigzag folds, so that the neck stretches out linearly when gas flows from the gas generator into the connecting section.

[0006] When the airbag is deployed and inflated, the neck is preferably narrower than the restraining part, as viewed in the transverse direction of the vehicle. It is sufficient that the neck is only slightly wider than the gas generator and, as viewed in the longitudinal direction of the vehicle, is much shorter than the restraining part of the airbag. Normally, the neck does not serve to assist the restraining effect of the airbag, so that material, installation space and filling volume can be reduced.

[0007] The main package may be wider than the length of the gas generator, such that the airbag module is shorter than the width in a longitudinal direction of the airbag module extending from the gas generator toward the airbag package.

[0008] In order to achieve a linear displacement effect, the folded connecting section is advantageously arranged between the gas generator and the main package. The gas generator, the connecting section and the main package are advantageously arranged along a straight line in the longitudinal direction of the module.

[0009] The connecting section and the main package can be brought together and arranged in the airbag package in such a way that the main package is not deployed until it is completely located in the vehicle passenger compartment.

[0010] The stretched-out connecting section, ie the neck, can have a length of approximately 5 cm to 50 cm, in particular 15 cm to 50 cm.

[0011] The length of the neck should be selected to be sufficient to enable the main package of the airbag package to be pushed preferably completely into the vehicle cabin. In a second function, the neck serves to position the restraining part of the airbag in the vehicle cabin when it is fully inflated. The optimum length of the neck is derived for the person skilled in the art from these two parameters.

[0012] In order to additionally influence the deployment of the airbag in the vehicle cabin, it is possible that the airbag has a first free end which defines the restraining portion, wherein the first free end is fixed in the region of the gas generator before the gas generator is activated via a limiting strap with a weakened area and the limiting strap remains intact at least until the neck is completely filled with gas. In this way, the deployment behavior can also be influenced when the main bag is already in the vehicle cabin. From a certain pulling force, the limiting strap releases, for example, by breaking at the weakened area, and the airbag can assume its final inflated shape.

[0013] The restraining portion of the airbag in the main bag can be both folded and rolled, so that the deployment can be controlled in a targeted manner even when the airbag has a complex shape.

[0014] In a preferred embodiment, the airbag is a front passenger airbag, wherein the airbag module is arranged in the region of the sun visor, in particular under the vehicle roof trim. The airbag then deploys outwards from the roof trim and is located in the space between the windshield and the vehicle occupant in the inflated state, wherein the airbag also extends above the instrument panel and the first end can form the lower end of the impact surface for the vehicle occupant.

[0015] In one possible embodiment of the invention, the vehicle occupant restraint system comprises an airbag module, which is mounted approximately in the center of the front passenger seat in the roof region on the front passenger side, as viewed in the transverse direction of the vehicle, and has an airbag which is grouped as an airbag package and which, in the restraint situation, is deployed between the windshield and the front passenger in order to receive the front passenger. The airbag package is arranged, for example, between the rotation axis of a sun visor of the vehicle and the windshield.

[0016] In other preferred embodiments, the airbag is a knee airbag, which is arranged in the lower region of the instrument panel or in the lower portion of the instrument panel. In this case, the airbag is deployed along the instrument panel or the steering column guard towards the direction of the passenger compartment.

[0017] Of course, the principles of the present invention can also be used for air bags at other locations in the vehicle, such as in a seat back.

[0018] In general, the gas generator is preferably arranged in the airbag module such that its longitudinal axis is perpendicular to a module longitudinal direction of the airbag module, wherein the module longitudinal direction coincides with the deployment direction of the airbag outwards from the airbag module in the installed state of the airbag module and points approximately in the vehicle longitudinal direction.

[0019] The gas generator is inserted directly into the blowing end of the airbag and is firmly connected to the airbag by sliding two opposite lugs of the airbag with fastening openings formed therein onto fastening screws protruding from the gas generator and thus sealing the blowing opening in a gas-tight manner.

[0020] If the airbag module is a front passenger module, then in order to fasten the airbag module to the roof frame, the gas generator is accommodated in a cross-sectionally C-shaped receptacle of a module bracket fastened to the roof frame, but the arms of the C-shaped receptacle on the vehicle cabin side do not protrude significantly from the gas generator.

[0021] The main package is gathered, for example, in such a way that the first free end is folded back to the blowing end. In addition, the two side edge sections of the restraining part are folded back toward the center and then rolled up. This allows an outer edge of the airbag to be filled first, which extends from the blowing end to the second free end of the airbag, which in the inflated state is approximately located in the transition from the windshield to the dashboard. In contrast, the filling gas does not initially flow into the inner edge of the airbag, which extends from the blowing end to the first free end of the airbag. This is achieved by the folds and the limiting bands of the restraining part of the airbag.

[0022] Starting from a certain filling level achieved after a first predetermined period of time after the activation of the gas generator, the limiting strap releases due to the acting tensile forces and the inner edge of the airbag and the first free end of the airbag are also fully inflated.

[0023] In the fully inflated state of the airbag, the first free end extends beyond the instrument panel toward the vehicle occupant and forms a collision surface between the first free end of the airbag and the blowing end of the gas generator on the side facing the vehicle occupant.

[0024] The airbag is preferably composed essentially of three outer wall sections, wherein a first outer wall section extends from the blowing end to the second free end and forms a support surface for supporting on the windshield, a second outer wall section connects the first free end to the second free end and is located on and above the instrument panel in the inflated state, and a third outer wall section connects the first free end to the blowing end and forms a cushioning surface in the inflated state.

[0025] The assembled airbag package is accommodated together with the gas generator in a cover, which is fastened to the fastening bolts of the gas generator via two retaining lugs on the gas generator side, while the main package of the assembled airbag package is inserted into the receiving cavity and is retained there via an airbag package fixing device constructed on the cover. The airbag package fixing device has a first fixing element and a second fixing element that are staggered and connected, which form a plug-in connection and are formed solely by the material of the cover, in particular the airbag fabric. The connecting section is located outside the receiving cavity and is fixed in a folded state by retaining lugs. In order to be fixed to the vehicle, the cover has one or more fixing sections, via which pre-fixation on the vehicle body can also be achieved, which pre-fixation enables accurate positioning of the airbag module and convenient installation of the load-bearing fixing device.

[0026] In the bottom of the receiving cavity of the covering, for example, a weakened area is provided, through which the main package of the gathered airbag package can come out of the airbag module and can be deployed from the roof trim into the vehicle passenger compartment.

[0027] All features described here in conjunction with the present invention can be implemented independently of one another individually or in any suitable combination according to the judgment of a person skilled in the art. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be described in detail below with reference to the accompanying drawings by means of embodiments.

[0029] Figure 1 is a schematic perspective view of a vehicle occupant restraint system according to the present invention, which has an airbag module mounted on a vehicle roof;

[0030] Figure 2 yes Figure 1 A module bracket of the airbag module shown is mounted on the vehicle roof;

[0031] Figure 3 yes Figure 1 A top view of the airbag module shown;

[0032] Figure 4 yes Figure 3 The view shown, in which the sun visor is additionally shown;

[0033] Figure 5 Installed in the vehicle Figure 1 A schematic cross-sectional view of a vehicle occupant restraint system is shown;

[0034] Figure 6 yes Figure 1 a schematic exploded view of the airbag module shown;

[0035] Figure 7 It is mounted on the roof Figure 1 A schematic top view of the airbag module shown;

[0036] Figure 8 and 9 yes Figure 1 A schematic cross-sectional view of a vehicle occupant restraint system is shown prior to air bag deployment and during an initial air bag deployment phase;

[0037] Figures 10 to 17 yes Figure 1 A schematic cross-sectional view of the inflation process of an airbag of the airbag module shown from a state before activation of the vehicle occupant restraint system until the airbag is fully filled;

[0038] Fig.18 yes Figure 1 A schematic cross-sectional view of an air bag of a vehicle occupant restraint system including an embedded gas generator;

[0039] Fig.19 yes Figure 1 A plan view of the third outer wall section of the airbag of the vehicle occupant restraint system, which is deployed in a planar manner in the uninflated state;

[0040] Figures 20 to 23 Insert the gas generator into Figure 1 A schematic diagram of the blown end of an air bag of a vehicle occupant restraint system;

[0041] Figures 24 to 27 yes Figure 1 The step of gathering an airbag of the vehicle occupant restraint system as viewed in a top view;

[0042] Fig.28 yes Figure 1 A schematic diagram of a clustered airbag package of a vehicle occupant restraint system is shown;

[0043] Fig.29 yes Fig.28 A schematic perspective view of the airbag package shown inserted into the cover;

[0044] Fig.30 yes Fig.29 A schematic top view of the illustrated package;

[0045] Fig.31 is a schematic perspective view of the package;

[0046] Figures 32 to 34 It is the insertion of the airbag package into the bag cover;

[0047] Fig.35 It is the detail of the air bag bag fixing device of the bag cover;

[0048] Fig.36is a schematic cross-sectional view of an air bag package inserted into a folding device;

[0049] Fig.37 and 38 It is the closure of the gas generator fixing device of the package;

[0050] Fig.39 is a schematic overview of an alternative method for inserting an air bag package into a package;

[0051] Figures 40 to 44 is a schematic diagram of the steps of an alternative method for inserting an air bag package into a package. DETAILED DESCRIPTION

[0052] Figures 1 to 7 The structure of a vehicle occupant restraint system 10 is shown, which in this example is designed to protect a front passenger, in particular of a passenger car, in the event of a frontal collision.

[0053] The vehicle occupant restraint system 10 includes an air bag module 12 (see in particular Figures 5 to 7 ), which comprises an airbag 16 that acts in the front and is grouped as an airbag package 14, and a gas generator 18 that provides a filling gas for inflating the airbag 16. The gas generator 18 is arranged in the airbag 16 and is therefore integrated into the airbag package 14.

[0054] The airbag package 14 and the gas generator 18 are accommodated in a flexible covering 20 (see, for example, Figure 7 and 29 ), which will be described in detail below and in Figures 1 to 6 The cover is omitted for clarity reasons.

[0055] In addition, a module support 22 is provided (see, for example, Figure 2 and 6 ), the airbag module 12 is fixedly mounted relative to the vehicle via the module carrier, for example, mounted on a roof frame 23 or other rigid component in the roof area of ​​the vehicle. The module carrier 22 is, for example, a sheet metal formed part.

[0056] The airbag module 12 is disposed at the lower portion of the roof guard plate 24 (see, for example, Figure 5 ), which is located between the windshield 26 of the vehicle and the rotation axis 28 or the suspension device 29 of the sun visor 30 as viewed in the longitudinal direction R of the vehicle. The sun visor 30 can be, for example, Figure 1 The sun visor 30 is pivoted about the rotation axis 28 as shown in FIG. The rotation axis 28 is not physically realized continuously. Instead, the sun visor 30 is pivotably fastened to the vehicle roof on two suspension devices 29 (see FIG. Figure 1 and 4), wherein the sun visor 30 can usually be unhooked at the one of the two suspension devices 29 on the inner side of the vehicle in order to fold it open laterally.

[0057] At least the gathered airbag package 14 and, if applicable, the gas generator 18 are located in front of the rotation axis 28 of the sun visor 30 in the vehicle direction R, viewed from the vehicle front to the vehicle rear.

[0058] The deployment direction E of the airbag 16 points in the direction of the front of the vehicle along the longitudinal direction R of the vehicle and initially extends approximately parallel to the roof and the windshield 26 .

[0059] The airbag module 12 is located approximately at the center above the passenger seat (not shown) on the passenger side when viewed in the vehicle transverse direction QF, so that the airbag 16 can receive the passenger in front. F Set away from the car door.

[0060] The module carrier 22 has a receptacle 32 which is C-shaped in cross section and surrounds the gas generator 18 at the gas generator-side end face of the airbag package 14 .

[0061] The gas generator 18 is a known, elongated tubular gas generator, from whose cylindrical outer side two fastening bolts 34 protrude radially. The fastening bolts 34 are located on the back side of the gas generator 18, and on the opposite front side, outflow openings (not shown) are provided, through which the filling gas leaves the gas generator 18 and passes directly into the airbag 16.

[0062] The gas generator 18 is arranged in the airbag module 12 such that its longitudinal axis extends transversely to the vehicle longitudinal direction R, approximately along the vehicle transverse direction QF and thus approximately perpendicularly to the module longitudinal direction M and the deployment direction E of the airbag 16. The module longitudinal direction M can be defined approximately by an extension of the diameter of the gas generator 18, which extends through the fastening bolt 34.

[0063] In the module carrier 22 , more precisely in the longitudinal side 36 of the C-shaped receptacle 32 between the two arms 38 of the C, a fastening opening 40 is provided (see Figure 2 ), fastening bolts 34 pass through these fastening openings to firmly fasten the gas generator 18 and the airbag package 14 to the module bracket 22. For example, the fastening bolts 34 can be fixed on the back side with nuts.

[0064] As a supplement to the two fastening bolts 34, a further bolt can be provided which forms a positioning bolt 42 (see, for example, Figure 7 A corresponding opening 44 is provided in the module support 22 (see Figure 2) This positioning screw 42 is used to prevent incorrect assembly of the gas generator 18 according to the error-proofing principle.

[0065] When the airbag 16 is deployed, filling gas flows from the gas generator 18 through the blowing end 46 into the airbag 16, which is fastened to the gas generator 18 as will be described in more detail below. Due to the pressure of the filled airbag 16, the roof trim 24 opens either at the weakened area or, for example, at the transition to the windshield 26 and allows the airbag 16 to emerge into the vehicle cabin. In this case, the roof trim 24 forms the lower limit of the ejection path for the airbag 16. The upper limit of this ejection path can be predetermined by the roof frame 23. In this example, there are no additional rigid guides, such as guide plates, between the airbag 16 and the roof trim 24.

[0066] The arm 38 of the C-shaped receptacle 32 on the vehicle passenger compartment side does not extend beyond the outer wall of the gas generator 18 in the vehicle longitudinal direction R and only increases the stability of the module bracket 22, so that this module bracket is only not significantly deformed during the deployment of the airbag 16, but does not help to guide the airbag 16 by direct contact with the airbag 16.

[0067] The deployed airbag 16 also does not come into contact with the sun visor 30 or its suspension 29 during its discharge into the vehicle passenger compartment due to its position on the roof frame 23 .

[0068] exist Figure 8 and 9 The initial deployment of the air bag 16 is illustrated in FIG.

[0069] Figures 10 to 17 The deployment and inflation of the air bag 16 is shown in greater detail. Figures 11 to 17 Can see the steering wheel in, but this steering wheel is only positioned on the side view selected for elaboration.In this example, air bag 16 is only deployed on the co-pilot side and beside the steering wheel.

[0070] Fig.10 Here, the initial state before the vehicle occupant restraint system 10 is activated is shown.

[0071] The airbag package 14 is first gathered under the closed roof trim 24. The airbag package 14 comprises two individually gathered or folded sections, namely a main package 48 and a connecting section 50 (for example, at Figure 1 and 3 ).

[0072] A restraining portion 52 of the airbag 16 is gathered in the main bag 48, which restraining portion comprises a large part of the airbag volume in the deployed and inflated state and which substantially determines the restraining effect of the airbag 16. This is for example Fig.17 and19 It can be seen in.

[0073] The neck 54 of the airbag 16 is formed between the blowing end 46 and the restraining portion 52 (see also Fig.19 ) is folded in the connecting section 50. In this example, the length of the neck 54 is approximately 5 to 40 cm, wherein a person skilled in the art can easily adapt the exact length to the actual conditions in the vehicle, such as the length of the firing path and the position of the impact surface of the airbag 16 in the inflated state.

[0074] The neck 54 is oriented along the airbag 16 perpendicular to the longitudinal direction L of the airbag (see, for example, Fig.19 ) or transverse Q perpendicular to the longitudinal direction M of the module G Much narrower than the restriction portion 52. For example, the width of the neck 54 is about 25 to 50% of the maximum width of the restriction portion 52 when the plane is unfolded. Therefore, the filling volume of the neck 54 is much smaller than the filling volume of the restriction portion 52.

[0075] In this embodiment, the neck 54 is not used to assist the restraint effect because it is placed directly on the roof high up in the vehicle. By reducing the volume of the neck 54 due to its reduced width, the material, filling gas and space in the airbag module 12 can be reduced.

[0076] The connecting section 50 and the main package 48 form two sections of the air bag package 14 that are folded independently of one another, as in the example Fig.36 As can be seen in .

[0077] The main package 48 is folded and rolled up, for example, as will be explained in more detail below, while the connecting section 50 is folded only in a zigzag manner with one to three folds in this example. The folds are arranged one behind the other in the longitudinal direction M of the module.

[0078] The gas generator 18 , the connecting section 50 and the main package 48 are arranged in a straight line one after another along the longitudinal direction M of the module.

[0079] With this arrangement, the filling gas from the gas generator 18 first reaches the neck 54 gathered in the connecting section 50. Due to the simple zigzag folding, the folds are filled one after another, which causes the connecting section 50 to stretch and thus exert a force acting in the module longitudinal direction M on the still folded main package 48.

[0080] This results in the main package 48 pushing the roof trim 24 aside and moving it into the vehicle cabin, still essentially folded. Fig.11 This situation is schematically shown in FIG.

[0081] At this point in time, still substantially no gas reaches the main bag 48 , since the gas flow is prevented by the still existing folds of the connecting section 50 .

[0082] Although this folding technology and the pushing of the main package 48 into the vehicle passenger compartment are described here in conjunction with an airbag module 12 fastened to the vehicle roof, according to the invention this technology can also be transferred to airbag modules used at other locations in the vehicle, for example in the knee area or in the seat back.

[0083] The fully inflated airbag 16 has a generally Y- or T-shape in side view (see Fig.17 ), wherein the handle of the Y or T is formed by the blowing end 46 and the neck 54. The restraining portion 52 includes a first free end 56 and a second free end 58. This can be done for the inflated airbag 16. Fig.17 As can be seen in FIG. 1 , for an uninflated, flat-expanded airbag 16, for example, in the side cross-sectional view showing the uninflated airbag 16 Fig.18 , wherein the stack, which is normally stacked flat on top of each other, is shown slightly pulled apart for reasons of clarity.

[0084] In the fully inflated state, the second free end 58 is located in the transition between the windshield 26 and the instrument panel 60 of the vehicle, while the first free end 56 extends in the direction of the vehicle occupant and generally forms the lower end of the airbag 16 and of the impact surface 62 for receiving the vehicle occupant.

[0085] The airbag 16 has essentially three large outer wall sections 64, 66, 68 (see Fig.18 ). The first outer wall section 64 extends from the blowing end 46 to the second free end 58 and, in the inflated state, forms a support surface for the airbag 16 on the windshield 26. The second outer wall section 66 extends from the second free end 58 to the first free end 56 and, in the inflated state, is located above the instrument panel 60. The third outer wall section 68 extends from the first free end 56 to the blowing end 46 and, in the inflated state of the airbag 16, forms a collision surface 62 for a vehicle occupant.

[0086] The neck 54 merges into the retaining portion 52 in the third outer wall section 68 by means of a shoulder 69 which is beveled on both sides, thereby forming a continuous transition from the neck 54 to the impact surface 62 (see Fig.19 ).

[0087] However, in the gathered main package 48, the first free end 56 is folded back in the direction of the blowing end 46, so that the sections 70, 72 of the third outer wall section 68 are folded back on themselves. Here, the free end 56 is initially connected to the blowing end 46 by the limiting band 74. This Fig.12 ,13 and 18 are shown in detail.

[0088] In this example, the limiting strap 74 is not fixed directly to the first free end 56, but is fixed offset by about 5 to 20 cm to the second outer wall section 66. As will be explained below, this makes it possible to fold the airbag package 14 more compactly.

[0089] This and the folding of the main bag 48, which will be described in detail below, has the effect that at the point in time when the main bag 48 reaches the vehicle cabin, the first free end 56 is still restrained in the roof region by the restraining strap 47. The remainder of the main bag 48 is then further unfolded in the vehicle cabin, wherein the filling gas flowing into the airbag 16 initially inflates only a partial region of the airbag 16.

[0090] exist Fig.14 and 18 It can be seen in FIG. 1 that at the point in time when the first free end 56 is still connected to the blowing end 46 via the limiting strap 74 , the airbag 16 has approximately a U-shape with an inner edge 76 and an outer edge 78 .

[0091] The inner edge 76 of the U is bounded toward the windshield 26 by the first outer wall section 64 of the airbag 16. The inner edge 76 is bounded toward the passenger compartment by the upper section 70 of the third outer wall section 68.

[0092] The outer edge 78 is bounded toward the instrument panel 60 by the second outer wall section 66 . The outer edge 78 is bounded toward the vehicle passenger compartment by the lower section 72 of the third outer wall section 68 .

[0093] The two sections 70, 72 of the third outer wall section 68 are initially held together by the limiting strip 74. In this way, the filling gas flows only into the inner edge 76, while the outer edge 78 remains essentially unfilled, even though the airbag package 14 has been largely deployed. Figures 12 to 15 This situation is shown in .

[0094] When a certain tensile force occurring with the preset filling volume of the airbag 16 is exceeded, the limiting band 74 is released after a first period of time after the gas generator 18 is activated. In this example, a weakened area 80 is formed on the surface of the limiting band 74 for this purpose (see Fig.18 ).

[0095] In this example, the neck 54 is already fully inflated at the point in time when the restraining strap 74 is released (see Fig.16 ).

[0096] In a second period subsequent to the first period, after the limiting strap 74 is broken into two parts at the weakened area 80, the air bag 16 is fully inflated. Fig.17 The fully inflated state is shown.

[0097] In the fully inflated state, the airbag 16 has a roughly Y- or T-shape when viewed from the side, since the inner edge 78 has been folded downward in the vehicle passenger compartment. The arms of the Y are formed by two inflated sections of the restraining part 52, which extend from the first and second free ends 56, 58 in the direction of the blowing end 46 and which merge into the neck 54.

[0098] Furthermore, a recess 82 is formed in the third outer wall section 68, which is rolled inwards in the folded state (see Fig.18 ), which partially bulges outward in the fully inflated airbag 16 and thereby enlarges the collision surface 62. However, the lower end of the cavity 82 is permanently connected to the second free end 58 via an internal limiting band 84 so that the shape of the inflated airbag 16 is stable.

[0099] As in Figures 20 to 23 As shown in , the gas generator 18 is preferably fixed on the blowing end 46 in the airbag 16 before the airbag 16 is gathered. However, if necessary, this step can also be performed after the airbag 16 is gathered.

[0100] The airbag 16 ends at the blowing end 46 with two opposite lugs 86, each extending over the entire width of the neck 54. Each of the lugs 86 has two fastening openings 88 and a positioning opening 90, which correspond in their arrangement to the fastening bolts 34 and positioning bolts 42 on the gas generator 18 (see, for example, Fig. 20 ).

[0101] Inside the airbag 16 , the two lugs 86 can each be reinforced with one or more reinforcing layers, which can optionally also have a heat-resistant and gas-tight coating.

[0102] To assemble the gas generator 18, place the gas generator between the two lugs 86 ( Fig.21 ), and then the two lugs 86 are placed individually on the gas generator 18, wherein the fastening opening 88 is correspondingly placed on the fastening bolt 34 and the positioning opening 90 is placed on the positioning bolt 42 ( Fig. 22 and 23 ).

[0103] Due to the wrapping of the two lugs 86 and the coating provided, if necessary, on the inner sides of the lugs 86 , the inflator-side blowing end 46 of the airbag 16 is now closed sufficiently gas-tightly.

[0104] The lug 86 is now also fixed to the fastening bolt 34 by means of a clamping washer and / or a nut (not shown).

[0105] In order to gather the airbags 16 into the airbag package 14, first, as in Fig.24 The airbag 16 is unfolded flat as shown in FIG. 1 , wherein the first end 56 is folded back toward the blowing end 46 .

[0106] The two legs 76, 78 of the airbag 16 lie one above the other in the region of the first free end 56. The third outer wall section 68 is folded back on itself in the sections 70, 72.

[0107] On the other hand, the first outer wall section 64 and the second outer wall section 66 each extend from the second free end 58 to the blowing end 46 .

[0108] The limiting band 74 is arranged in such a way that its free end lies on the blowing end 46 .

[0109] In a first folding step, the first free end 56 is now rolled over once about a folding line 92 perpendicular to the airbag longitudinal direction L (which in the flat unfolded airbag 16 coincides with the module longitudinal direction M), but not onto an attachment point 94 of the limiting strap 74 on the second outer section 66 (see Fig.24 and 25 ). Depending on the shape of the airbag, this folding step can also be omitted.

[0110] Now, in a second folding step, the two side regions of the airbag 16 are folded inwardly in a zigzag fold along folding lines 96, 98 extending parallel to the longitudinal direction L of the airbag. Fig.25 and 26 The two fold lines 98 are now along the transverse direction Q G The airbag 16 is delimited laterally outwardly.

[0111] The spacing of the folding lines 96, 98 from one another and from the peripheral edge of the airbag 16 is selected such that no overlapping of the side regions of the airbag 16 occurs in the center of the airbag, wherein the center of the airbag 16 is defined by an imaginary center straight line G which extends from the blowing end 46 to the second free end 58 and is arranged symmetrically with respect to the blowing end 46.

[0112] The airbag 16 can be symmetrical in the deployed state with respect to this center straight line G, but this is not absolutely necessary but is determined primarily by the geometry of the passenger compartment, the windshield 26 and the instrument panel 60 .

[0113] In the winding step, the second free end 58 is now wound. Fig.26 The airbag 16 shown, which is already partially folded, is wound, for example, three to ten turns, in particular six turns, in the direction of the blowing end 46. Fig. 27The result of this folding step is shown in FIG. The rolled-up area now forms the main package 48. Here, the airbag 16 is rolled up only to the end of the restraining portion 52 of the airbag 16. This folding step does not involve extending in the direction of the blowing end 46 (see FIG. Fig.26 and 27 ) of the neck 54 and the area of ​​the limiting band 74.

[0114] In a further folding step, the area of ​​the neck 54 and, if appropriate, the limiting strap 74 protruding from the main package 48 is now folded in a simple zigzag folding manner, for example, with one to three folds, wherein the folding line 100 is oriented perpendicularly to the module direction M and thus parallel to the longitudinal axis (not shown here) of the gas generator 18. The assembled airbag package 14 now has Fig. 27 and 36 The shape shown in .

[0115] The same hole structure 88, 90 as on the lug 86 of the airbag 16 is also realized on the free end of the limiting belt 74, and the limiting belt 74 is also put on the fastening bolt 34 and the positioning bolt 42 by means of the fastening opening 88 and the positioning opening 90 (see also Fig.36 ). The two lugs 86 and the limiting band 74 are now stacked in three layers, wherein the fastening bolts 34 of the gas generator 18 are passed through all three aligned fastening openings 88 . The same applies to the positioning openings 90 .

[0116] In the installed state, the airbag 16 is connected to the module carrier 22 in a load-bearing manner via the fastening screws 34 . The tensile forces acting on the limiting straps 74 are also transmitted to the module carrier 22 via the fastening screws 34 .

[0117] After the gas generator 18 is placed and the airbag 16 is gathered, the airbag package 14 has Fig.28 in the form shown.

[0118] After the gas generator 18 has been fixed in the airbag 16 and the airbag 16 has been assembled to form the airbag package 14 , the airbag package 14 together with the gas generator 18 is inserted into the covering 20 .

[0119] Figures 29 to 35 The covering 20 is shown in detail.

[0120] In this example, the cover 20 is composed completely (except for any seams, of course) of the airbag fabric and is assembled from precisely two blanks 102, 103 (see Fig.30 ).

[0121] The packaging 20 has a receiving pocket 104 (see Fig.31), which is formed by two overlapping sections of the first blank 102 and is used to accommodate the main package 48 of the air bag package 14. The bottom 106 of the receiving bag 104 is provided with a weakened area 108 (see, for example Fig.30 ) and extends along a direction B perpendicular to the module direction M.

[0122] The two edges 110 of the receiving pocket 104 facing away from the bottom 106 (see Fig.31 ) are integrally and seamlessly turned into a retaining lug 112. The two retaining lugs 112 form a gas generator fixing device 114 for fixing the gas generator 18 in the sheath 20 and have an opening pattern at their free ends, which corresponds to the arrangement of the fastening bolts 34 and the positioning bolts 42. Two fastening openings 88 and a positioning opening 90 are correspondingly arranged on the free edge of each retaining lug 112.

[0123] The receiving pocket 104 and the retaining lug 112 are realized together in the first blank 102 by folding the first blank 102 back on itself and partially connecting the longitudinal edges connected to the folding line to form the receiving pocket 104. The free section that protrudes outwards beyond the receiving pocket 104 then forms the retaining lug 112 (see, for example, Fig.30 and 31 ).

[0124] One of the retaining lugs 112, namely Fig.31 The lower center, flat, open retaining lug 112 is separated from the surrounding rest of the first blank 102 by a U-shaped cutting line 116. The cutting line 116 produces a stirrup 118, which has two strap sections 120 located on the sides of the retaining lug 112 and a connecting bridge 122 connecting the two strap sections 120. The strap section 120 is integrally transferred into the receiving pocket 104 at its end opposite the bridge 122.

[0125] The stirrup 118 is part of an airbag package fastening device 124. This airbag package fastening device also has at least one pair of first and second fastening elements 126, 128, which can be plugged together and thus fixed against each other. Here, two pairs of fastening elements 126, 128 are provided, which are arranged side by side parallel to the direction B of the base 106. The exact position and number of the fastening elements and their design are of course determined by the judgment of the skilled person.

[0126] In this example, the first fixing element 126 is configured on the second blank 103, which extends above the receiving pocket 104 parallel to the direction B of the bottom. The first fixing element 126 has the form of an arrow-shaped hook in this example (see in particular Fig.30 and 35 ), these hooks are formed on the edge of the second blank 103 pointing to the bottom 106.

[0127] Two second fixing elements 128 are formed in the bridge 122 and are each formed by an elongated opening through which the hook of the first fixing element 126 can be inserted by hooking its edge around the edge of the opening and fixing the first fixing element 126 on the bridge 122 . Fig.35 A detailed view of the fixing elements 126 , 128 is shown.

[0128] In this embodiment, the second blank 103 is made of a multi-layer airbag fabric, while the first blank 102 is cut from a single-layer airbag fabric. The cutting is performed by laser cutting, so that the edges of the multi-layers are welded directly to one another in the second blank 103 without having to fix the edges that are in contact with one another separately. Since the first fixing elements 126 are thus also made of a multi-layer airbag fabric, they have sufficient rigidity to be hooked into the openings of the second fixing elements 128.

[0129] The second blank 103 extends beyond the receiving pocket 104 laterally, ie parallel to the bottom direction B. A fastening section 130 is formed at each of its free ends, which serves to secure the covering 20 in a fixed manner relative to the vehicle. This fastening does not have to bear the entire load of the deployed airbag 16, but rather serves primarily to position the airbag module 12 on the roof frame 23.

[0130] However, the fastening sections 130 are also used here to pre-fasten the airbag module 10 in the vehicle. For this purpose, each of the fastening sections 130 has, in addition to a fastening opening 132, through which, for example, a screw for fixed fastening relative to the vehicle is inserted, a further pre-fastening opening 134, into which a fastening clip 136 is inserted (see Fig.34 When the airbag module 10 is mounted on the vehicle, the fastening clips 136 are pushed into openings on the roof frame 23 or on the module carrier 22 and the airbag module 10 is held in position until final fastening has been achieved.

[0131] The fastening openings 132 and the pre-fastening openings 134 are arranged in the two fastening sections 130 one above the other parallel to the module longitudinal direction M, but in a different sequence (see for example Fig.30 ).

[0132] In order to insert the airbag package 14 into the package cover 20, the main package 48 is first pushed into the receiving pocket 104 (see Fig.31 and 32). The two retaining lugs 112 are then placed once with the fastening opening 88 and the positioning opening 90 onto the fastening bolts 34 and the positioning bolts 42 of the gas generator 18 so that they grip the gas generator 18 and of course the blowing end 46 of the airbag 16 on the back side of the gas generator 18 (see 32 and 33 as well as 37 and 38).

[0133] The two retaining lugs 112 can have different lengths l1, l2 along the module longitudinal direction M, as for example in Fig.37 As shown in . In this way, the tensile force acting on the fastening bolt 34 of the gas generator 18 via the retaining lug 112 can be adjusted to a certain extent. This has the result that the orientation of the gas generator 18 with respect to the rotation about its longitudinal axis can be determined by selecting the length of the retaining lug 112. Normally, it is desired that the fastening bolt 34 extends exactly in the module longitudinal direction M. However, it can also be beneficial, for example to simplify the assembly on the roof frame, if the bolt 34 is tilted a few degrees relative to the module longitudinal direction M. Since the gas generator 18 usually has a planar gas outlet area (not shown), a tilting of a few degrees does not affect the gas outflow and the inflation performance of the airbag 16.

[0134] After the gas generator fixture 114 is closed as described (in Fig.33 ), the stirrup 118 is now placed on the retaining lug 112. In the next step, the bridge 122 is pushed under the second blank 103 and the hook of the first fixing element 126 is passed through the opening of the second fixing element 128 (see Fig.34 ). The belt section 120 is now located above the main package 48 of the air bag package 14 on the side of the retaining lugs 112 and securely holds this main package in the receiving pocket 104. The air bag package fastening device 124 is thus closed.

[0135] The airbag package 14 including the covering 20 can now be inserted into the module carrier 22 in order to install the airbag module 10 on the vehicle.

[0136] When the airbag module 10 is activated, the weakened area 108 on the bottom 106 of the receiving pocket 104 opens so that the airbag package 14 can come out. The gas generator fastening 114 , the airbag package fastening 124 and the fastening to the vehicle via the fastening section 130 remain closed.

[0137] In order to better fix the zigzag folds of the neck 54 in the connecting section 50 during the insertion of the airbag package 14 into the covering 20, an intermediate covering 140 can be used in an alternative method, such as Figures 39 to 44 As described.

[0138] The intermediate jacket 140 is a substantially rectangular airbag fabric having a hole pattern corresponding to the fastening bolts 34 and the positioning bolts 42 of the gas generator 18 at both free ends, the hole pattern including two fastening openings 88 and one positioning opening 90 (see Fig.39 ).

[0139] First, the assembled airbag package 14 including the gas generator 18 is enclosed in the intermediate package 140, wherein the two ends of the intermediate package 140 are placed on the bolts 34 and 42 of the gas generator 18. Fig.40 , it is shown that a known folding device 136 is used.

[0140] The airbag package 14 , which is securely surrounded by the intermediate package 140 , is now inserted into the package 20 , wherein the main package 48 is pushed into the receiving pocket 104 (see Fig.41 ).

[0141] The intermediate casing 140 is now opened again by removing its two ends from the bolts 34, 42 of the gas generator 18. Fig.42 Shown in.

[0142] Now, one of the two retaining lugs 112 of the sheath 20 is placed onto the bolts 34, 42 of the gas generator 18 in order to fix the sheath 20 to the gas generator 18. Fig.43 As shown in , the intermediate covering 140 can be pulled out from between the airbag package 14 and the covering 20. In this case, in particular, the folding of the connecting section 50 can no longer be changed, because the one holding lug 112 already connected to the gas generator 18 holds the airbag package 14 in its desired shape.

[0143] After the intermediate casing 140 has been removed, the second retaining lugs 112 are also closed by sliding their openings over the bolts 34 , 42 of the gas generator 18 .

[0144] Finally, the airbag package fastening device 124 is also closed by sliding the stirrup 118 onto the gas generator 18 and the retaining lugs 112 surrounding the gas generator as described above, pushing the bridge 122 under the second blank 103 and closing the fastening elements 126 , 128 .

Claims

1. A vehicle occupant restraint system comprising an airbag module (12), which is arranged under a roof trim (24) of a vehicle in the region of a sun visor (30), the airbag module having an airbag (16) and a gas generator (18) which, when activated, supplies the airbag (16) with filling gas, wherein: The airbag (16) is assembled into an airbag package (14) before activation, thereby forming a main package (48) and a connecting section (50), wherein the main package includes a restraining portion (52) of the airbag (16) that constitutes a large part of the airbag volume, and the connecting section includes a neck (54) of the airbag (16), which connects the restraining portion (52) to the gas generator (18), wherein the restraining portion (52) and the neck (54) are folded differently, wherein the main package (48) of the airbag package (14) is folded along the gas generator (18) The airbag (16) is wider in the longitudinal direction than the connecting section (50), wherein the stretched connecting section (50) has a length of 5 cm to 50 cm, the airbag (16) has a first free end (56) which defines the restraining portion (52), wherein the first free end (56) is fixed in the area of ​​the gas generator (18) via a limiting band (64) having a weakened area (80) before activation, and the limiting band (64) remains intact at least until the neck (54) is completely filled with gas.

2. The vehicle occupant restraint system according to claim 1, characterized in that: The neck (54) is folded into one to three zigzag folds.

3. The vehicle occupant restraint system according to claim 1 or 2, characterized in that: In the deployed and inflated airbag (16), the neck (54) is in the vehicle transverse direction (Q F ) is observed to be narrower than the constrained portion (52).

4. The vehicle occupant restraint system according to claim 1, characterized in that: The folded connecting section (50) is arranged between the gas generator (18) and the main package (48).

5. The vehicle occupant restraint system according to claim 1 or 2, characterized in that: The connecting section (50) and the main package (48) are brought together and arranged in the airbag package (14) such that the main package (48) is not deployed until it is completely located in the vehicle passenger compartment.

6. The vehicle occupant restraint system according to claim 1, characterized in that: The stretched connecting section ( 50 ) has a length of 15 cm to 50 cm.

7. The vehicle occupant restraint system according to claim 1 or 2, characterized in that: The restraining portion (52) in the main bag is both folded and rolled.

8. The vehicle occupant restraint system according to claim 1 or 2, characterized in that: The airbag (16) is a passenger airbag.

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