DE102014204080B4 - Airbag module for a motor vehicle - Google Patents

Abstract

Airbag module for a vehicle, with an airbag (13) which, in the unfolded state, has at least one impact section (15) facing a vehicle occupant (3), into which the vehicle occupant (3) plunges in the event of a crash, the impact section (15) of the unfolded The airbag (13) has at least one trough-like depression (21, 23) which is arched into the airbag contour by an offset amount (Δt) and which simulates a negative shape of the side of the vehicle occupant's (3) body which comes into contact with the impact section (15), the Airbag module is installed in a steering wheel (41), and wherein an airbag inflow opening (43) is positioned centrally in the area of a steering axis (L) of the steering wheel (45), and wherein the steering wheel airbag (13) covers the entire steering wheel (45) covered, and the circle center point (M) of the steering wheel airbag (13) is positioned by a height offset (Δh) in the vehicle vertical direction (z) above the airbag inflow opening (43), so that during the deployment process the gas flow initially into the lower thorax - the impact section (19) is directed and only then, with a time lag, is the upper head impact section (17) also filled, characterized in that the steering wheel airbag (13) is circular in the unfolded state, and that the contour of the trough-shaped depression (21 , 23) is defined by at least one tether (33), with which the airbag fabric arches into the airbag interior in the area of the depression (21, 23) with a tensile force (Fz) acting against the airbag internal pressure (p). and that the tether (33) is tubular, specifically with a circumferentially closed cross-section (34) at the airbag impact section (15) connected to the tether end (35).

Description

The invention relates to an airbag module for a motor vehicle according to the preamble of patent claim 1.

Complex legal crash requirements have to be met, especially in the case of front airbags, that is to say in the case of driver and/or front passenger airbags. These are tested as part of a standardized crash simulation in which occupant stress values are recorded in the event of a crash using impactors and/or dummies. Of particular relevance here are the load values in the head, neck and thorax area when plunging into the deployed airbag.

From the DE 10 2009 036 333 A1 an airbag module is known, the airbag of which, in the unfolded state, has an impact section facing the vehicle occupant, into which the vehicle occupant dives with support in the event of a crash.

In order for the crash simulation to meet the legal crash requirements, depending on the environment in the vehicle interior, the impact section of the airbag must be designed in such a way that the head and thorax of the vehicle occupant can alternately immerse themselves in the deployed airbag with varying degrees of hardness or softness, possibly with different forward displacement paths, in order to reduce the total occupant load to reduce.

From the DE 10 2010 039 759 A1 a generic gas bag arrangement for a steering wheel of a motor vehicle is known. An airbag system for a motor vehicle is known from US 2005/0 057 029 A1. Inflatable airbag assemblies with lateral and longitudinal straps are known from US 2011/0 062 693 A1. From the DE 10 2013 100 212 A1 a driver's airbag with improved head and neck injury prevention is known. An airbag is known from US 2001/0 033 072 A1.

The object of the invention is to provide an airbag module for a motor vehicle in which legally prescribed crash load values can be complied with in a crash simulation in a simple manner.

The object is solved by the features of claim 1. Preferred developments of the invention are disclosed in the dependent claims.

The invention is based on the problem that in a conventional airbag in the unfolded state, a constant internal pressure prevails throughout, as a result of which the possible variations with regard to the shape of the contour in the impact section of the airbag are reduced. Against this background, according to patent claim 1, the impact section of the unfolded airbag has at least one trough-like depression.

This arches into the airbag contour by an offset amount and forms a negative shape of the side of the vehicle occupant's body that comes into contact with the airbag impact section. The trough-like depression forms a recess in which the side of the vehicle occupant's body can dip at least partially with reduced application of force. In this way, when the vehicle occupant plunges into the unfolded airbag, the load applied to the vehicle occupant can be distributed in such a way that the crash load values for the vehicle occupant are reduced overall.

The airbag is preferably a driver or passenger airbag which has a thoracic impact section and/or a head impact section, whereby the vehicle occupant can support his head or chest area on the impact section of the airbag in the event of a crash. Both the thoracic impact section and the head impact section preferably have a trough-like depression. The trough-like depressions are designed in such a way that they each simulate the negative shape of the occupant's head and the negative shape of the occupant's chest area.

If the vehicle occupant is displaced forwards as a result of a crash, the trough-shaped head impact section thus provides a recess into which the nose and eye area of the vehicle occupant can immerse, specifically when the load is reduced. The load is thus applied more to the outer field of vision of the vehicle occupant. The same is true for the trough-shaped thoracic impact section, where the load is applied more to the outer ribs of the vehicle occupant while the inner ribs are relieved.

The trough-shaped head impact portion as well as the trough-shaped thoracic impact portion may be provided as two recesses positioned at a distance from each other. In contrast, the two indentations can converge at a connecting section to form a common trough-shaped indentation. The connecting portion linking the thoracic cavity and the head cavity forms a neck impact portion.

The contour of the at least one trough-shaped depression is defined by at least one tether. The tether may come before extended to extend inside the airbag. One end of the tether is attached directly to the airbag impact section, while the opposite end is attached to the fabric section of the airbag opposite the airbag impact section.

In an embodiment variant not covered by the invention, a number of strip-shaped tethers can be provided. These can, for example, be connected circumferentially distributed at the edge of the recess at a distance from one another. To form an apex in the recess, one of the tethers is attached to the inside of the airbag impact section, specifically in the area of the apex, and pulls the corresponding airbag fabric inwards with a tensile force, forming the trough. According to the invention, a tubular tether is used, which has a circumferentially closed cross-section, especially at its connection end, which is connected (that is, sewn) to the airbag impact section. In order to ensure trouble-free deployment of the airbag, it is preferred if the tubular limiting strap is designed in the form of a slit, that is to say has at least one flow passage.

In an embodiment that saves material and weight, the tether can have at least one branch point between its end connection points on the inner wall of the airbag, from which at least one partial tether branches off. The partial band can be connected to the airbag impact section with its end facing away from the branching point. In this way, when the airbag is deployed, the tethers have a lattice-like structure, in which a perfect retaining function of the tethers can be realized with reduced material expenditure.

According to the invention, the airbag module is installed in a steering wheel. In this case, the airbag inflow opening is positioned approximately in the middle in the area of the steering axis. To form a head impact section and a thorax impact section, the steering wheel airbag can each have an upper tether and a lower tether that draw in the airbag fabric in the impact sections while forming trough-shaped depressions, i.e. subject it to a tensile force.

When deployed, the steering wheel airbag is circular and essentially covers the entire steering wheel. With regard to proper support of the vehicle occupant moving forward, the center point of the steering wheel airbag is positioned according to the invention by a height offset in the vertical direction of the vehicle above the airbag inflow opening. In addition, it is advantageous if the lower tether is wider in the vehicle transverse direction and shorter in the vehicle longitudinal direction than the upper tether. In this way it is achieved that during the deployment process the gas flow is first directed into the lower thoracic impact section and only then, with a time lag, is the upper head impact section also filled, whereby the steering wheel airbag is deployed less aggressively for the vehicle occupants.

The advantageous embodiments and/or developments of the invention explained above and/or reproduced in the subclaims can be used individually or in any combination with one another, except, for example, in cases of clear dependencies or incompatible alternatives.

The invention and its advantageous training and developments and their advantages are explained in more detail below with reference to drawings.

• 1 in einer schematischen Seitenansicht einen Versuchsaufbau für eine Frontalcrash-Simulation;
• 2 in einer perspektivischen Teilansicht einen entfalteten Beifahrer-Airbag mit seinem, dem Beifahrer zugewandten Aufprallabschnitt;
• 3 eine Ansicht entsprechend der 2 mit teilweisem Aufriss;
• 4 ein zweites Ausführungsbeispiel des Beifahrer-Airbags in einer Seitenschnittansicht;
• 5 ein weiteres Ausführungsbeispiel in einer Ansicht entsprechend der 2;
• 6 und 7 jeweils Ansichten eines entfalteten Lenkrad-Airbags.

Show it:

• 1 in a schematic side view a test setup for a frontal crash simulation;
• 2 in a perspective partial view, an unfolded passenger airbag with its impact section facing the passenger;
• 3 a view according to the 2 with partial elevation;
• 4 a second embodiment of the passenger airbag in a side sectional view;
• 5 another exemplary embodiment in a view corresponding to FIG 2 ;
• 6 and 7 each view of a deployed steering wheel airbag.

In the 1 a test setup for a frontal crash simulation is indicated, in which a dummy 3 simulating the front passenger is arranged with a head impactor and a thorax impactor in a vehicle interior 1 and is secured to the vehicle seat 7 via a safety belt 5 . The vehicle interior 1 is bounded at the front by an instrument panel 7, in which an airbag module 9, indicated only roughly schematically, is arranged. The airbag module 9 has a housing, not shown in detail, on which a gas generator 11 and a fabric section of the airbag are held. In the 1 the airbag 13 is shown in its unfolded state, as a result of which a forward displacement path of the dummy 3 in the direction of travel FR is limited.

In the 1 the front crash simulation is carried out specifically with a seated vehicle occupant. However, the invention is not limited to this case. Rather, the invention also relates to passive load cases in which the vehicle occupant is not wearing a seat belt. In the 2 An impact portion 15 of the unfolded airbag 13 facing the dummy 3 is shown in an enlarged partial perspective view. Accordingly, the impact portion 15 is divided into an upper head impact portion 17 and a lower thoracic impact portion 19, which are arranged one above the other in the vehicle vertical direction z. Both the lower thoracic impact section 19 and the upper head impact section 17 have trough-like depressions 21, 23 which are spaced apart from one another by a height offset Δz. The upper trough-like depression 21 is essentially pot-shaped, specifically with a depression base 24 that is arched into the airbag contour by an offset dimension Δt, from which a side wall 27 extends at a base edge 26 . In the further course, this merges into a base impact surface at an outer peripheral edge 29 .

The recess 21 is designed geometrically so that it corresponds approximately to a negative shape of an occupant's head. In the event of a crash, the depression 21 forms a recess into which the nose and eye area of the occupant's head can dip with reduced load application. The load on the occupant's head is therefore applied to a greater extent at the peripheral edge 29 of the depression 21, i.e. outside the field of vision of the vehicle occupant 3.

The depression 23 of the thoracic impact section 19 is designed with a larger surface area and here (viewed from the front) has, for example, the shape of an approximately upright rectangle. The depression 23 of the thoracic impact section 19 is specially designed so that in the event of a crash, the outer ribs of the vehicle occupant are more likely to be subjected to a load, while the inner ribs can dip into the depression 23 with only a reduced load.

The special geometry of the head and thorax impact sections 17, 19 is achieved by tethers 33 which extend inside the airbag 13. The tethers 33 are according to the 3 sewn with a connecting end 35 inside the airbag impact portion 15 and sewn with a second connecting end 37 on an airbag rear side 38 facing away from the vehicle occupant 3 . In the unfolded state, the catch straps 33 act as traction means which, when subjected to a tensile force Fz ( 1 ) Draw in the airbag fabric in the area of the impact section 15, with the formation of the depressions 21, 23. For example, a number of tethers 33 can be provided, which are attached to the bottom edge 26 of the depressions 21, 23, specifically at a distance from one another and circumferentially distributed along the bottom edge 26 of the recess 21.

Alternatively, to form the upper depression 21 ( 3 ) Instead of a number of individual tethers 33, only one tubular tether 33 can be used. The tubular tether 33 has according to the 3 at its first connection end 35 a circumferentially closed cross-section 34 ( 3 ) which draws in the airbag fabric to form the bottom edge 26 of the recess 21 . In order to ensure trouble-free deployment of the airbag, the tubular catch strap 33 is slot-shaped, that is designed with flow passages 36 .

In the 4 the illustrated tethers 33 have additional branching points 39 between their two end attachment points 35, 37. A partial band 41 branches off from each branching point 39 and is connected to the airbag impact section 15 with its opposite connecting end 35, specifically with the formation of the airbag contour according to the invention in the impact section 15.

In the 5 a further embodiment variant is shown in which, in contrast to the previous exemplary embodiments, the two depressions 21, 23 for the head impact section 17 and for the thorax impact section 19 converge at a connecting section 44 to form a common depression. The connection section 44 in particular forms an additional neck impact section in order to reduce the crash loads in the neck area of the vehicle occupant.

A passenger airbag is shown in each of the above exemplary embodiments. In contrast, in the following 6 and 7 a steering wheel airbag 13 for the driver is shown. According to the 6 the airbag module 9 is built into a steering wheel 45 . The airbag inflow opening 43 is positioned centrally in the area of a steering axis L of the steering wheel 45 . The steering wheel airbag 13 has an upper tether 33 and a lower tether 33 to form the head impact section 17 and the thorax impact section 19 .

According to the 6 and 7 the steering wheel airbag 13 is circular in the unfolded state and essentially covers the entire steering wheel 45. The circle center point M of the steering wheel airbag 13 is according to FIG 7 positioned above the airbag inflow opening 43 by a height offset Δh in the vehicle vertical direction z. In addition, the lower tether 33 is wider in the vehicle transverse direction y and in the vehicle longitudinal direction direction x shorter than the upper tether 33. In this way it is achieved that during the unfolding process the gas flow is first directed into the lower thoracic impact section 19 and only then, with a time lag, is the upper head impact section 17 also filled, whereby the steering wheel is unfolded -Airbags 13 less aggressive for the vehicle occupant 3 takes place.

Claims (7)

Airbag module for a vehicle, with an airbag (13) which, in the unfolded state, has at least one impact section (15) facing a vehicle occupant (3), into which the vehicle occupant (3) plunges in the event of a crash, the impact section (15) of the unfolded The airbag (13) has at least one trough-like depression (21, 23) which is arched into the airbag contour by an offset amount (Δt) and which simulates a negative shape of the side of the vehicle occupant's (3) body which comes into contact with the impact section (15), the Airbag module is installed in a steering wheel (41), and wherein an airbag inflow opening (43) is positioned centrally in the area of a steering axis (L) of the steering wheel (45), and wherein the steering wheel airbag (13) covers the entire steering wheel (45) covered, and the circle center point (M) of the steering wheel airbag (13) is positioned by a height offset (Δh) in the vehicle vertical direction (z) above the airbag inflow opening (43), so that during the deployment process the gas flow initially into the lower thorax - impact section (19) is directed and only then, with a time delay, is the upper head impact section (17) also filled, characterized in that the steering wheel airbag (13) is circular in the unfolded state, and that the contour of the trough-shaped depression (21 , 23) is defined by at least one tether (33) with which the airbag fabric in the area of the recess (21, 23) is pulled into the airbag interior with a tensile force (F _z ) acting against the airbag interior pressure (p). arches, and that the tether (33) is tubular, specifically with a circumferentially closed cross-section (34) at the airbag impact section (15) connected to the tether end (35). Airbag module after claim 1 , characterized in that the impact portion (15) of the airbag (13) is divided into a thoracic impact portion (19) for a thoracic impact and a head impact portion (17) for a head impact of the vehicle occupant (3), and that the thorax - The impact section (19) and/or the head impact section (17) have a trough-like depression (21, 23) which simulates the negative shape of the occupant's head and/or the occupant's chest area. Airbag module after claim 1 or claim 2 , characterized in that two indentations (21, 23) are provided, which are separated from one another by a distance (Δz), or in that two indentations (21, 23) are provided, which converge at a connecting section (44) to form a common indentation, wherein the connecting portion (44) is a neck impact portion. Airbag module according to one of the preceding claims, characterized in that the tether (33) is arranged inside the airbag (13) and is connected with one end (35) to the airbag impact section (15), and that the connection end (35) of the tether (33) at an apex (S ₁ , S ₂ ) at the bottom of the recess (21, 23) attacks. Airbag module according to one of the preceding claims, characterized in that the tubular catch strap (33) is designed with at least one flow passage (36) for trouble-free deployment of the airbag. Airbag module according to one of the preceding claims, characterized in that the tether (33) has at least one branch point (39) between its end attachment points (35, 37), from which at least one partial strap (41) branches off and is attached to the airbag impact section (15) is connected. Airbag module according to one of the preceding claims, characterized in that the steering wheel airbag (13) has an upper tether (33) and a lower tether (33) to form the head impact section (17) and the thorax impact section (19). .

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