Front airbag module for mounting on or in an instrument panel of a motor vehicle, as well as vehicle occupant safety system and motor vehicle with such a front airbag module

Abstract

The invention relates to a front gasbag module (18) with a gasbag (22) and a module housing (26) in which the gasbag (22) and a gas generator (28) are accommodated, wherein the gasbag (22) in the inflated state has a cushion section (30) with an impact surface (32) and an opposing support surface (34), and a neck section (36) which fluidly connects a gasbag opening (38) to the cushion section (30), wherein a retaining strap (40) is provided which has a first retaining strap end (42) attached to the neck section (36) of the gasbag (22) and an opposing second retaining strap end (44), wherein an activatable retaining strap release device (46) is provided which is connected to the second retaining strap end (44) in a non-activated state and releases the second retaining strap end (44) in an activated state, wherein the gasbag (22) is inflated when the retaining strap release device is not activated (46) takes on a first contour,in which the neck section (36) is held in a folded position by the retaining strap (40) such that movement of the impact surface (32) towards the occupant (24) is limited, and wherein, when the retaining strap release device (46) is activated, the airbag (22) assumes a second contour in which the neck section (36) fully unfolds and the impact surface (32) can thus move freely towards the occupant (24). Furthermore, the invention also relates to a vehicle occupant safety system (50) and a motor vehicle (10) with such a front airbag module (18).

Description

[0001] The invention relates to a front airbag module for mounting on or in an instrument panel of a motor vehicle in the direction of travel in front of a vehicle steering wheel, as well as a vehicle occupant safety system and a motor vehicle with such a front airbag module.

[0002] To improve occupant safety, airbag modules are used as restraint devices in vehicles. So-called front airbags are frequently employed, in which an airbag inflates in front of the vehicle occupant, cushioning the impact, especially the occupant's head, in the event of a crash. A distinction is made between driver-side and passenger-side airbags. Passenger-side airbags are located in the instrument panel and, compared to driver-side airbags, which are located in the steering wheel, have a larger airbag volume. They therefore also have a larger restraint area.

[0003] Furthermore, airbags that deploy from the instrument panel have the advantage that their restraint effect is independent of the steering wheel design. With traditional steering wheels, the largely circular rim provides a large, symmetrical support surface against which a front airbag deploying from the steering wheel hub can be effectively braced in the event of an occupant impact. This support effect for the front airbag is limited with modern steering wheel designs, such as those with an almost rectangular rim or one interrupted at the 12 o'clock position (so-called yoke steering wheels).

[0004] Therefore, there are increasing efforts to also accommodate the driver's side front airbag in the instrument panel, analogous to the passenger side front airbag.

[0005] The arrangement of gasbags in the instrument panel is more difficult for driver's side gasbags than for passenger side gasbags, because the steering wheel, which is positioned in front of the instrument panel and acts as a disruptive contour, can hinder the deployment of the gasbag.

[0006] In addition, the arrangement of the gasbag module in the instrument panel can impair the deployment trajectory of the gasbag, which runs at least partially between the windshield and the instrument panel.

[0007] Finally, with the ongoing development of automated driving functions, the occupant seating position also varies considerably from a traditional, steering-hand-adjacent position in manual driving mode to a more reclined, relaxed comfort position in automated or autonomous driving mode. To ensure optimal restraint for the vehicle occupant in the event of a crash, it would be desirable for the front airbag to have different deployment geometries depending on the occupant's seating position.

[0008] The object of the invention is therefore to provide a front airbag module for mounting on or in an instrument panel of a motor vehicle in the direction of travel in front of a vehicle steering wheel, wherein the front airbag module unfolds safely between the vehicle steering wheel and the occupant and furthermore has different unfolding geometries depending on an occupant seating position.

[0009] According to the invention, this problem is solved by a front gasbag module for mounting on or in an instrument panel of a motor vehicle in the direction of travel in front of a vehicle steering wheel, comprising an inflatable gasbag for restraining an occupant positioned behind the vehicle steering wheel in the direction of travel, and a module housing in which the folded gasbag and a gas generator for filling the gasbag with generator gas are accommodated, wherein, in the inflated state, the gasbag extends in an arc shape from the module housing in the direction of travel, first along the windshield to the rear and then downwards between the occupant and the vehicle steering wheel.In its inflated state, the gasbag has a cushion section with an impact surface facing the occupant and an opposing support surface facing the vehicle steering wheel, as well as a neck section that fluidly connects a gasbag mouth of the gasbag, which is fixed in the module housing, to the cushion section, wherein at least one retaining strap is provided which has a first retaining strap end attached to the neck section of the gasbag and an opposite second retaining strap end, wherein an activatable retaining strap release device is provided which is connected to the second retaining strap end in a non-activated state and releases the second retaining strap end in an activated state.With the safety strap release device deactivated, the inflated airbag assumes a first contour in which the neck section is held in a folded or gathered position by the at least one safety strap. This shortens the neck section in the longitudinal direction of the vehicle, thus limiting movement of the impact surface towards the occupant. With the safety strap release device activated, however, the inflated airbag assumes a second contour in which the neck section fully unfolds in the longitudinal direction of the vehicle, allowing the impact surface to move freely towards the occupant without hindrance from the at least one safety strap.

[0010] This results in an adaptive front airbag on the driver's side, providing good restraint regardless of the steering wheel design, and whose deployment geometry can be advantageously adapted to a seating position. Since the adaptability is achieved in the slim neck area of ​​the front airbag, the overall volume of the airbag increases only slightly due to the release of the retaining strap, so that the desired internal pressure for occupant restraint is quickly reached in the second airbag contour as well. Furthermore, the desired, advantageously shaped structure of the impact surface for occupant restraint remains unchanged in both the first and second contours of the airbag.

[0011] Preferably, the safety strap release device is mounted on or inside the module housing. The safety strap release device is, for example, a pyrotechnically or electrically driven actuator that releases the second end of the safety strap upon receiving an electrical signal. The existing module housing of the gas bag module can serve as a stable support to which the safety strap release device is securely and reliably attached. In another embodiment, the gas generator housed within the module housing forms a stable support, with the safety strap release device then being mounted directly on the gas generator or even integrated into it.

[0012] The invention further comprises a motor vehicle with a windscreen, an instrument panel, a steering wheel and a front airbag module as described above, wherein the front airbag module is attached to or in the instrument panel.

[0013] In particular, the front gasbag module is attached to or within the instrument panel in such a way that the gas flow direction as it exits the gas generator is approximately parallel to the windshield. This reduces the stress on the windshield caused by the deploying gasbag when the front gasbag module is activated.

[0014] Preferably, the front airbag module is arranged in the area of ​​a windshield root of the vehicle, with a gap between the windshield and the instrument panel forming a launch channel for the front airbag module. Upon module activation, the airbag deploys within this channel, with the neck section extending through the gap when the airbag is inflated. The windshield root is defined as the leading edge of the windshield in the longitudinal direction of the vehicle, where the windshield and the instrument panel meet. In this position, a gas flow direction essentially parallel to the windshield can be achieved particularly easily. The position of the impact surface of the front airbag in the longitudinal direction of the vehicle can then be adjusted with minimal effort via the neck section located in the gap between the windshield and the instrument panel.

[0015] According to one embodiment of the vehicle, a head-up display is arranged below the firing channel between the front airbag module and the steering wheel. These head-up display systems are enjoying increasing popularity and can project a wide variety of vehicle information onto an area of ​​the windshield.

[0016] The front airbag described above can also be advantageously used on the passenger side. In this case, the steering wheel is no longer present as a disruptive and supportive contour, so that the front airbag is supported by the instrument panel.

[0017] Furthermore, the invention also comprises a vehicle occupant safety system with a front airbag module described above, wherein an additional airbag module is provided for installation in the vehicle steering wheel, and wherein the additional airbag module has a support airbag that unfolds between the support surface of the airbag section and the vehicle steering wheel when the release strap is activated. Activation of the release strap leads to a (further) unfolding and a resulting extension of the neck section, thus enabling the impact surface to move further towards the occupant. The support airbag then advantageously stabilizes the airbag section of the front airbag in this position when the occupant impacts the impact surface.The control of the additional gasbag module is preferably coupled with the control of the safety belt release device, so that the additional gasbag module is activated at a predetermined time interval from the safety belt release device or simultaneously with the safety belt release device.

[0018] Finally, the invention relates to a motor vehicle with such a vehicle occupant safety system, a windscreen, an instrument panel and a vehicle steering wheel, wherein the front airbag module is attached to or in the instrument panel and the additional airbag module is attached to or in the vehicle steering wheel.

[0019] Further features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the drawings. These show: - Fig. 1 a schematic longitudinal section through a motor vehicle according to the invention with a vehicle occupant safety system according to the invention and a front airbag module according to the invention in a driving position of the occupant; - Fig. 2 the schematic longitudinal section of a motor vehicle according to Fig. 1 in a comfortable position of the occupant according to one embodiment; - Fig. 3 the schematic longitudinal section of a motor vehicle according to Fig. 1 in a comfortable position of the occupant according to an alternative embodiment; - Fig. 4 a schematic longitudinal section of a motor vehicle with a front gasbag module according to the invention in a first mounting position; - Fig. 5 a schematic longitudinal section of a motor vehicle with a front gasbag module according to the invention in a second mounting position; - Fig. 6 a schematic longitudinal section through another variant of a motor vehicle with a vehicle occupant safety system and a front gasbag module in a driving position of the occupant; - Fig. 7 the schematic longitudinal section of a motor vehicle according to Fig. 6 in a comfortable position of the occupant according to one embodiment; - Fig. 8 the schematic longitudinal section of a motor vehicle according to Fig. 6 in a comfortable position of the occupant according to an alternative embodiment.

[0020] The Fig. 1 and Fig. Figures 2 each show a schematic longitudinal section through a motor vehicle 10 with a windshield 12, an instrument panel 14, a steering wheel 16 and a (deployed) front airbag module 18, which is attached to or in the instrument panel 14 (see also Fig. 4 and 5).

[0021] The front gasbag module 18, which is mounted in the direction of travel 20 in front of the vehicle steering wheel 16 on or in an instrument panel 14 of the motor vehicle 10, comprises an inflatable gasbag 22 for restraining an occupant 24 positioned in the direction of travel 20 behind the vehicle steering wheel 16, and a module housing 26 in which the folded gasbag 22 and a gas generator 28 for filling the gasbag 22 with generator gas are accommodated.

[0022] When inflated, the gasbag 22 extends in an arc shape from the module housing 26 in the direction of travel 20, first along the windshield 12 to the rear and then downwards between the occupants 24 and the vehicle steering wheel 16, wherein the gasbag 22 inflated has a cushion section 30 with an impact surface 32 facing the occupant 24 and an opposing support surface 34 facing the vehicle steering wheel 16, as well as a neck section 36 which fluidly connects a gasbag mouth 38 of the gasbag 22, which is fixed in the module housing 26, with the cushion section 30.

[0023] Furthermore, the front gasbag module 18 comprises at least one retaining strap 40, which has a first retaining strap end 42 attached to the neck section 36 of the gasbag 22 and an opposite second retaining strap end 44, wherein an activatable retaining strap release device 46 is provided which is connected to the second retaining strap end 44 in a non-activated state and releases the second retaining strap end 44 in an activated state.

[0024] The safety strap release device 46 of the front gasbag module 18 is attached to or within the module housing 26. In particular, the safety strap release device 46 can be arranged directly on the gas generator 28 or even integrated into it, as shown in the Fig. 1 and Fig. 2 indicated.

[0025] In the event of a triggering of the front airbag module 18 with the safety strap release device 46 not activated, the inflated airbag 22 assumes a first contour in which the neck section 36 is held in a folded or gathered position by the at least one safety strap 40 such that the neck section 36 is shortened in the longitudinal direction 47 of the vehicle and thus a movement of the impact surface 32 in the direction of the occupant 24 is limited by the at least one safety strap 40 (cf. Fig. 1) This allows for good occupant restraint if the occupant 24 assumes a driving position according to Fig. 1 assumes an upright seating position in which the motor vehicle 10 is manually controlled via the vehicle steering wheel 16. To keep the neck section 36 in its gathered or inverted position according to Fig. To keep 1, several retaining straps 40 are provided in particular, the first retaining strap ends 42 of which are distributed over the circumference of the neck section 36 and are attached to the gas bag 22, the retaining straps 40 are then first brought together and finally connected to the retaining strap release device 46 via a common second retaining strap end 44.

[0026] In the event of a triggering of the front airbag module 18 with the safety strap release device 46 activated, the inflated airbag 22 assumes a second contour in which the neck section 36 fully unfolds in the longitudinal direction 47 of the vehicle and the impact surface 32 can thus move unhindered by the at least one safety strap 40 in the direction of the occupant 24 (cf. Fig. 2) This allows for good occupant restraint when the occupant 24 is in a comfortable position according to Fig. 2 assumes a relaxed reclining position in which the motor vehicle 10 is not controlled by the occupant 24, but via an autonomous or (partially) automated driving function.

[0027] In the comfort position, compared to the driving position, the vehicle seat 48 is adjusted backwards and / or the backrest of the vehicle seat 48 is swivelled backwards, so that the occupant 24 has a greater distance to the vehicle steering wheel 16 and the instrument panel 14. This greater distance is at least partially compensated for by the adaptive contour of the airbag 22, thereby achieving good restraint regardless of the occupant 24's seating position.

[0028] Since the gas bag 22 has a larger volume when deployed into its second contour than when deployed into its first contour, the gas generator 28 is optionally a two-stage gas generator 28, in which a second generator stage is only triggered when the restraint release device 46 is also activated and deployment of the gas bag 22 into its second contour is therefore desired. Alternatively, a separate auxiliary generator can be provided, which is operated analogously to the second generator stage. In this way, the internal pressure in the second contour of the gas bag 22 can be increased if this is desired for occupant restraint.

[0029] Based on the Fig. 1 and Fig. The front airbag module 18 described in section 2 is part of a vehicle occupant safety system 50 of the motor vehicle 10, the vehicle occupant safety system 50 of course having further airbag modules, such as side and / or knee airbag modules.

[0030] The Fig. Figure 3 shows an embodiment of the motor vehicle 10 in which the vehicle occupant safety system 50, in addition to the front airbag module 18 described above, also includes an additional airbag module 52 for installation in the vehicle steering wheel 16. This additional airbag module 52 has a support airbag 54 which, when the safety strap release device 46 is activated, unfolds between the support surface 34 of the cushion section 30 and the vehicle steering wheel 16.

[0031] Activation of the restraint release device 46 leads to a (further) unfolding and a resulting extension of the neck section 36, thus enabling the impact surface 32 to move further towards the occupant 24. The support gas bag 54 then advantageously stabilizes the cushion section 30 of the gas bag 22 in this position when the occupant 24 impacts the impact surface 32. Control of the additional gas bag module 52 is preferably coupled with control of the restraint release device 46, so that the additional gas bag module 52 is activated at a predetermined time interval from the restraint release device 46 or simultaneously with the restraint release device 46.

[0032] The support gasbag 54 is therefore not a voluminous front gasbag for direct occupant restraint, but merely serves as a support for the cushion section 30 of the gasbag 22. Compared with the first contour of the gasbag 22 in Fig. 1 the impact surface 32 in the second contour of the gas bag 22 according to Fig. 3 is stabilized by the support airbag 54 in a position that is significantly closer to the occupant 24. Thus, in the event of a frontal impact of the vehicle 10, the acceleration distance of the occupant 24 can be reduced, thereby improving occupant safety, especially if the occupant is in a comfortable position according to Fig. 3 occupies.

[0033] The vehicle occupant safety system 50 according to Fig. 3 therefore includes the front gasbag module 18, which is attached to or in the instrument panel 14, and the additional gasbag module 52, which is attached to or in the vehicle steering wheel 16.

[0034] The Fig. 4 and Fig. Figure 5 shows the motor vehicle 10 with the front gasbag module 18 in a first or second mounting position.

[0035] According to Fig. In Figure 4, the front airbag module 18 is mounted in the instrument panel 14 directly behind a display device 56, for example, a monitor. In this so-called basic position, the front airbag module 18 is located close to the occupant 24, so that after module deployment, the deployment distance to the occupant 24 is comparatively short. A disadvantage of this mounting position is the high stress on the windshield 12, since the front airbag module 18 opens upwards and the deploying airbag 22 is deflected at the windshield 12 in the direction of the occupant 24, as indicated by arrow 58 in Figure 4. Fig. 4 indicated. Therefore, measures may be necessary to reduce the deployment pressure of the gas bag 22 on the windscreen 12 and to prevent the windscreen 12 from breaking.

[0036] To reduce the load on the windshield 12, the front windshield airbag module 18 is designed according to Fig. 5 attached to (or in) the instrument panel 14 such that the direction of gas flow when exiting the gas generator 28 is approximately parallel to the windshield 12, as indicated by an arrow 60 in Fig. 5 indicated. In this so-called windscreen root position, the front gasbag module 18 is arranged in the area of ​​the windscreen root, i.e., in a contact area between the windscreen 12 and the instrument panel 14, with a gap 62 between the windscreen 12 and the instrument panel 14 forming a firing channel for the front gasbag module 18, in which the gasbag 22 unfolds upon activation of the front gasbag module 18, the neck section 36 extending through the gap 62 when the gasbag 22 is inflated. Since the gasbag 22 does not need to be deflected by the windscreen 12 in this case, there is less stress on the windscreen 12 after module deployment compared to mounting the front gasbag module 18 in the basic position as shown in Figure 5. Fig. 4, significantly lower.

[0037] In addition, head-up displays (64) are increasingly used on the driver's side, which project warnings or information directly onto a section of the windscreen (12) in front of the driver.

[0038] According to Fig. 5 is a device 64 for a head-up display arranged below the firing channel between the front gasbag module 18 and the vehicle steering wheel 16. When the front gasbag module 18 is mounted in the basic position according to Fig. 4 the front gasbag module 18 is positioned significantly closer to the vehicle steering wheel 16, so that the integration of the device 64 for a head-up display cannot be realized at all or at least is difficult.

[0039] Based on the variant of motor vehicle 10 according to the Fig. In addition to sections 1 to 3, an alternative variant with the front airbag module 18 is presented below, whereby the basic idea of ​​an adaptive airbag 22, which can assume a first or a second airbag contour depending on the seating position of the occupant 24, remains unchanged. Therefore, only the distinguishing features of the variants will be discussed below, and otherwise reference is made to the description above.

[0040] In the case of the front gasbag module 18 according to the Fig. 1 to 3 the neck section 36 is held in a folded or gathered position by at least one retaining strap 40, so that the gas bag 22 assumes its first contour, wherein an activatable retaining strap release device 46 is provided which can actively release the retaining strap 40, so that the gas bag 22 assumes its second contour.

[0041] In contrast, the modular version is implemented according to the Fig. 6 to 8 of the neck section 36 is held in the folded or gathered position by a releasable fastening means, in particular a tear seam 66, so that the airbag 22 assumes the first contour. As already described above, this first contour enables good occupant restraint when the occupant 24 assumes a driving position according to Fig. 6 assumes an upright seating position in which the motor vehicle 10 is manually controlled via the vehicle steering wheel 16. In this driving position of the occupant 24, the internal pressure of the airbag is insufficient to release the releasable fastening device.

[0042] If the internal pressure of the airbag rises above a predetermined pressure threshold, the releasable fastening is released, allowing the neck section 36 to fully unfold in the longitudinal direction 47 of the vehicle until the airbag 22 reaches its second contour. As described above, the second contour provides good occupant restraint when the occupant 24 assumes a comfortable position according to Fig. 7 assumes a relaxed reclining position in which the motor vehicle 10 is not controlled by the occupant 24, but via an autonomous or (partially) automated driving function.

[0043] The comfort position of the occupant 24 is detected by means of sensors and / or camera monitoring, whereupon an increased gasbag internal pressure is requested when the front gasbag module 18 is triggered. The front gasbag module 18 has, for example, two separate gas generators or (as in Fig. (7 indicated) a multi-stage gas generator 28 with a first stage 68 and a second stage 70, wherein the second gas generator or second generator stage is only activated in the comfort position of the occupant 24. The additional generator gas of the second gas generator or second generator stage increases the internal pressure of the gas bag beyond the predetermined pressure threshold, so that, for example, the tear seam 66 tears open or the releasable fastening is otherwise released and the gas bag 22 finally expands into its second contour according to Fig. 7 unfolded.

[0044] The unfolding of the gas bag 22 into its second contour is achieved indirectly here by an increase in the gas bag's internal pressure and a tearing of the rupture seam 66, which, compared to a targeted, active release of the retaining strap according to the Fig. 1 to 3 entails a larger tolerance range. At the same time, according to the Fig. 6 to 8, however, also include the activatable catch strap release device 46 and the catch strap 40, which advantageously simplifies the construction of the front gasbag module 18.

[0045] Analogous to the vehicle occupant safety system 50 with activatable retaining strap release device 46 and retaining strap 40, an additional gas bag module 52 can also be provided in the variant with tear seam 66 or detachable fastening device, with a support gas bag 54, which unfolds between the support surface 34 of the cushion section 30 and the vehicle steering wheel 16 when the second stage 70 of the gas generator 28 is activated (see figure). Fig. 8) Regarding functional details and technical advantages, please refer to the above explanations. Fig. 3 referred.

Claims

[1] Front gasbag module for mounting on or in an instrument panel (14) of a motor vehicle (10) in the direction of travel in front of a vehicle steering wheel (16) with an inflatable gas bag (22) for restraining an occupant (24) positioned in the direction of travel (20) behind the vehicle's steering wheel (16), and a module housing (26) in which the folded gas bag (22) and a gas generator (28) for filling the gas bag (22) with generator gas are accommodated, wherein the gasbag (22) in the inflated state extends in an arc shape from the module housing (26) in the direction of travel (20) first to the rear and then downwards between the occupants (24) and the vehicle steering wheel (16), wherein the gasbag (22) in the inflated state has a cushion section (30) with an impact surface (32) facing the occupant (24) and an opposing support surface (34) facing the vehicle steering wheel (16), and a neck section (36) which fluidly connects a gasbag mouth (38) of the gasbag (22) fixed in the module housing (26) with the cushion section (30), wherein at least one retaining strap (40) is provided which has a first retaining strap end (42) attached to the neck section (36) of the gas bag (22) and an opposite second retaining strap end (44), wherein an activatable trap release device (46) is provided which is connected to the second trap end (44) in a non-activated state and releases the second trap end (44) in an activated state, wherein the gasbag (22) assumes a first contour when the retaining strap release device (46) is not activated, in which the neck section (36) is held in a folded or gathered position by the at least one retaining strap (40) such that the neck section (36) is shortened in the longitudinal direction (47) of the vehicle and thus a movement of the impact surface (32) towards the occupant (24) is limited by the at least one retaining strap (40), and wherein the gas bag (22) assumes a second contour when the safety strap release device (46) is activated, in which the neck section (36) fully unfolds in the longitudinal direction of the vehicle (47) and the impact surface (32) can thus move unhindered by the at least one safety strap (40) in the direction of the occupant (24). [2] Front gasbag module according to claim 1, characterized by that the release device (46) is attached to or inside the module housing (26). [3] Motor vehicle comprising a windscreen (12), an instrument panel (14), a steering wheel (16) and a front airbag module (18) according to any of the preceding claims, characterized by , that the front gasbag module (18) is attached to or in the instrument panel (14). [4] Motor vehicle according to claim 3, characterized by , that the front gasbag module (18) is attached to or in the instrument panel (14) in such a way that the direction of flow of the gas when exiting the gas generator (28) is approximately parallel to the windscreen (12). [5] Motor vehicle according to claim 3 or 4, characterized by, that the front gasbag module (18) is arranged in the area of ​​a windscreen root of the motor vehicle (10), wherein a gap (62) between the windscreen (12) and the instrument panel (14) forms a firing channel of the front gasbag module (18) in which the gasbag (22) unfolds upon module activation, wherein in the inflated state of the gasbag (22) the neck section (36) extends through the gap (62). [6] Motor vehicle according to claim 5, characterized by , that a device (64) for a head-up display is arranged below the firing channel between the front gasbag module (18) and the vehicle steering wheel (16). [7] Vehicle occupant safety system with a front airbag module (18) according to claim 1 or 2, characterized by, that an additional gasbag module (52) is provided for installation in the vehicle steering wheel (16), wherein the additional gasbag module (52) has a support gasbag (54) which unfolds between the support surface (34) of the cushion section (30) and the vehicle steering wheel (16) when the catch strap release device (46) is activated. [8] Motor vehicle comprising a windscreen (12), an instrument panel (14), a vehicle steering wheel (16) and a vehicle occupant safety system (50) according to claim 7, characterized by , that the front gasbag module (18) is attached to or in the instrument panel (14) and the additional gasbag module (52) is attached to or in the vehicle steering wheel (16).

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