Side curtain air bag design

A side curtain airbag (110, 210, 310, 410, 510) for use with a linear gas generator or inflator. In one embodiment, the airbag (110, 210, 310, 410) includes a first longitudinal panel (113, 213, 313, 413), a second longitudinal panel (114, 214, 314, 414) adjacent the first panel, and a plurality of seams (116, 220, 320, 420) connecting the adjacent panels to define a plurality of inflation fluid flow passages (117, 217, 317, 417) between the scams. The seams extend along a substantial portion of a lateral extent of the airbag. The seams are also distributed along substantially an entire length of the airbag. In another embodiment, the airbag includes a first panel (513), a second panel (514) adjacent the first panel, and a plurality of substantially straight seams (520) connecting the adjacent panels to define a plurality of inflation fluid flow passages (517) between the seams (520). Use of the seam patterns described herein in side airbag systems allows for improved airbag performance, particularly when used in conjunction with a linear inflator. Inflation of the airbag takes place in a more uniform manner, reducing the risk of localized overpressurization and seam bursting, and improving occupant protection. Moreover, the seam patterns disclosed herein are relatively simple, and their manufacture is relatively easy ands inexpensive.

BACKGROUND OF THE INVENTION

The invention relates to inflatable motor vehicle airbags. More particularly, the invention relates to airbags that protect a vehicle passenger from side impact collisions.

Side impact airbags are utilized in motor vehicles for protecting occupants from injury due to impact with an interior side of a vehicle. A side impact airbag may be designed for use with a linear inflator, which is known in the art and differs from conventional inflators primarily in that inflation gas is discharged substantially uniformly along a length of the inflator. Conventional inflators, in contrast, typically include a single gas nozzle outlet, and are used in conjunction with a distribution pipe extending along an airbag. Referring toFIG. 1, there is illustrated an inflatable airbag10in accordance with a known design. Airbag10includes a plurality of seams20connecting adjacent panels or sides of an airbag body12. Arrows “A” indicate approximate directions of the flow of inflation gas inside the airbag body12, delivered via a linear inflator (not shown) extending along a top edge15of airbag body12. Seams20restrict the predominant flow of gas to certain paths. Linear inflators, because they distribute gas uniformly along their length, can create localized overpressurization and seam failure when used with typical airbags incorporating seam patterns such as those shown inFIG. 1.

SUMMARY OF THE INVENTION

The present invention broadly provides a side curtain airbag having minimal obstruction to the flow of inflation gas, particularly for use with a linear gas generator or inflator. In one embodiment, the airbag includes a first longitudinal panel, a second longitudinal panel adjacent the first panel, and a plurality of elliptically-shaped seams connecting the adjacent panels to define a plurality of inflation fluid flow passages between the seams. The seams extend along a substantial portion of a lateral extent of the airbag. The seams are also distributed along substantially an entire length of the airbag. In another embodiment, the airbag includes a first panel, a second panel adjacent the first panel, and a plurality of substantially straight seams connecting the adjacent panels to define a plurality of inflation fluid flow passages between the seams. Use of the seam patterns described herein in side airbag systems allows for improved air bag performance, particularly when used in conjunction with a linear inflator. Inflation of the airbag takes place in a more uniform manner, reducing the risk of localized overpressurization and seam bursting, and improving occupant protection. Moreover, the seam patterns disclosed herein are relatively simple, and their manufacture is relatively easy and inexpensive.

DETAILED DESCRIPTION

FIGS. 2-6show various embodiments of side curtain airbags in accordance with the present invention. Prior to deployment, the side airbag is rolled or folded in a space along a roof rail (not shown) of a vehicle and is concealed by the interior headliner material (not shown) of the vehicle. Upon airbag activation, the inflation gas produces sufficient pressure to cause the airbag to break through the headliner material and deploy. The length of the airbag such that it extends along the side of the vehicle interior proximate a driver or a front seat passenger and thus offers protection for either the driver or the passenger. The features described herein are particularly applicable to (but are not restricted to) side impact air bags.

Referring toFIG. 2, in a system utilizing a linear inflator (not shown) in conjunction with airbag110, the linear inflator is preferably positioned longitudinally along a top edge115of airbag body112. Thus, inflation gas from the inflator is discharged substantially uniformly along the length of the inflator and directed substantially uniformly into airbag body112. One suitable linear inflator is described in U.S. Pat. No. 5,094,475 to Olsson et al., hereby incorporated by reference. Arrows “B” inFIG. 2illustrate a predominant flow direction of inflation gases within the airbag body112.

Referring again toFIG. 2, there is shown a first embodiment of the present invention comprising an airbag110having an airbag body112formed from a first longitudinal panel113, a second longitudinal panel114adjacent first panel113, and a plurality of elliptically-shaped seams116connecting panels113and114to define a plurality of inflation fluid flow passages117between the seams. Seams116are aligned in a pair of longitudinal rows and are substantially evenly spaced along each row. Pairs of elliptically-shaped seams116are connected by substantially straight laterally-extending seams120oriented generally perpendicular to top edge115of airbag body112, and thus substantially parallel to direction “B” of the predominant flow of inflation gas.

In the embodiment shown inFIG. 2, straight seams120are of substantially equal lengths to provide corresponding flow passages117having substantially equal lengths. In addition, seams120are preferably substantially evenly spaced along a length “L” of airbag body112to provide flow passages117having substantially equal cross-sectional areas. Furthermore, it may also be seen that inflation fluid flow passages117formed by seams116and120are in fluid communication with each other and with a flow passage119extending substantially perpendicular to fluid flow passages117. These features help to prevent overpressurization in localized regions of the airbag interior and ensure substantially uniform inflation of airbag110. It may also be seen from the drawings that seams120extend along a substantial portion of a lateral extent of the airbag, and that the seams are also distributed along substantially an entire length of the airbag.

In a particular embodiment of the present invention, shown inFIG. 2, one or more of elliptically-shaped seams116has a substantially circular shape (i.e., the shape of the seam has an eccentricity of approximately zero.) It is recognized for purposes of the present invention that a circle is a type of ellipse which has an eccentricity of zero.

Refining now toFIG. 3, there is shown an airbag210according to a second embodiment of the present invention. Airbag210is similar in structure to airbag110and has an airbag body212formed from a first panel213and a second panel214adjacent first panel213. However, rather than a plurality of elliptically-shaped seams connected by substantially linear seams, panels213and214of airbag210are connected only by a plurality of relatively larger laterally-extending substantially elliptically-shaped seams220to define a plurality of inflation fluid flow passages217between the seams. Seams220are preferably oriented such that the major axes of the ellipses defined thereby are laterally-extending and substantially parallel. Thus, inflation gas flowing into airbag body212, indicated by arrows “C”, passes substantially uniformly between the sewn or otherwise attached elliptically-shaped seams220.

In the embodiment shown inFIG. 3, elliptically-shaped seams220have major axes220-aof substantially equal lengths to provide corresponding flow passages217having substantially equal lengths. In addition, the minimum separation distances d2between adjacent seams220are preferably substantially equal along a length “L” of airbag body212, thereby providing flow passages217having substantially equal cross-sectional areas. It may also be seen from the drawings that seams220extend along a substantial portion of a lateral extent of the airbag, and that the seams are distributed along substantially an entire length of the airbag. Furthermore, it may also be seen that inflation fluid flow passages217formed by seams220are in fluid communication with each other and with a flow passage219extending substantially perpendicular to fluid flow passages217.

Referring now toFIG. 4, there is shown an airbag310according to a third embodiment of the present invention. Airbag310is similar to airbag210, illustrated inFIG. 3, and has an airbag body212formed from a first panel313, a second panel314adjacent first panel313, and a plurality of elliptically-shaped seams320connecting panels313and314to define a plurality of inflation fluid flow passages317between the seams. However, the elliptically-shaped seams shown inFIG. 4have relatively larger minor axes than the seams shown inFIG. 3(i.e., the elliptically-shaped seams ofFIG. 4have smaller eccentricities than the elliptically-shaped seams ofFIG. 3.) Similar to airbag210, inflation gas flows between the elliptically-shaped seams320, in a direction substantially parallel with the major axes of the elliptically-shaped seams.

In the embodiment shown inFIG. 4, seams320have major axes320-aof substantially equal lengths to provide corresponding flow passages317having substantially equal lengths. In addition, the minimum separation distances d3between adjacent seams320are preferably substantially equal along a length “L” of airbag body312, thereby providing flow passages317having substantially equal cross-sectional areas. Furthermore, it may also be seen that inflation fluid flow passages317formed between seams320are in fluid communication with each other and with a flow passage319extending substantially parallel with the minor axes320-bof elliptically-shaped seams.

FIG. 5illustrates yet another airbag410, according to fourth embodiment of the present invention. Airbag has an airbag body412formed from a first panel413, a second panel414adjacent first panel413, and a plurality of elliptically-shaped seams420connecting panels413and414to define a plurality of inflation fluid flow passages417between the seams. In this embodiment, seams420are substantially circular and are arranged in one or more substantially parallel rows450and451. Seams420may also be substantially evenly spaced apart along a row. In addition, as seen inFIG. 5, seams arranged along a first row450of the substantially parallel rows form a zigzag pattern with seams arranged along a second row451of the substantially parallel rows. The predominant direction of inflation gas flow is illustrated inFIG. 5with arrows “E”. In alternative embodiments (not shown), the arrangement of the substantially circular seams420may be non-linear, otherwise structured, or random.

FIG. 6illustrates an airbag510according to a fifth embodiment of the present invention. Airbag510includes an airbag body412formed from a longitudinal first panel513, a longitudinal second panel514adjacent first panel513, and a plurality of substantially straight seams520, defining a plurality of fluidly connected inflatable regions522. Seams520are substantially parallel and are spaced apart substantially evenly. Seams extend substantially parallel to a direction F in which an inflation gas exits an inflator. Substantially straight seams520assist in channeling the gas flow from a linear inflator (not shown) in a direction substantially parallel to an orientation of the seams, similar to the foregoing embodiments.

Referring toFIGS. 7 and 8, using any of the airbag embodiments described above, the dimensions and the spacing of elliptically-shaped seams may be adapted to control the distance traveled by the head of a passenger prior to being stopped by the airbag.FIG. 7shows the airbag embodiment shown inFIG. 3, andFIG. 8shows an edge view of the embodiment inFIG. 7in an inflated state. As seen inFIGS. 7 and 8, a pair of adjacent seams220and220′ extends along a plane P defined along the intersection of airbag panels213and214. It may also be seen that the minimum separation distance d between the pair of adjacent seams may be adjusted such that a portion222of the airbag projects at least a predetermined distance D out of plane P when the airbag is inflated. The distance D can be specified so as to limit the travel of a passenger's head prior to impacting the airbag (i.e., for a relatively greater projection distance D, the passenger's head will travel a relatively shorter distance prior to impacting the airbag.)

Any of the airbag embodiments described above may also be incorporated into an airbag system200(not shown). Airbag system200includes at least one airbag110,210,310,410,510in accordance with an embodiment of the present invention, and a linear inflator100coupled to the airbag so as to enable fluid communication with an interior of the airbag. Inflator100is configured to discharge inflation gas substantially uniformly along a length of the airbag. As described above, airbag embodiments110,210,310,410include a first panel, a second panel adjacent the first panel, and a plurality of elliptically-shaped seams connecting the panels to define a plurality of inflation fluid flow passages between the seams. Also as described above, airbag embodiment510includes an airbag body412formed from a first panel, a second panel adjacent first panel, and a plurality of substantially straight seams defining a plurality of fluidly connected inflatable regions. Airbag system200may also include (or may be in communication with) a crash event sensor210including a known crash sensor algorithm that signals actuation of airbag system200via, for example, activation of airbag inflator100in the event of a collision. At least a portion of the airbag110,210,310,410,510is configured to cover a side wall of a vehicle when the airbag is inflated.

Airbag system200may also be incorporated into a broader, more comprehensive vehicle occupant restraint system180including additional elements such as a safety belt assembly150(not shown).FIG. 4shows a schematic diagram of one exemplary embodiment of such a restraint system180.

Safety belt assembly150includes a safety belt housing152and a safety belt101extending from housing152. A safety belt retractor mechanism154(for example, a spring-loaded mechanism) may be coupled to an end portion153of the belt. In addition, a safety belt pretensioner156may be coupled to belt retractor mechanism154to actuate the retractor mechanism in the event of a collision. Typical seat belt retractor mechanisms which may be used in conjunction with the safety belt embodiments of the present invention are described in U.S. Pat. Nos. 5,743,480, 5,553,803, 5,667,161, 5,451,008, 4,558,832 and 4,597,546, incorporated herein by reference. Illustrative examples of typical pretensioners with which the safety belt embodiments of the present invention may be combined are described in U.S. Pat. Nos. 6,505,790 and 6,419,177, incorporated herein by reference.

Safety belt system150may also include (or may be in communication with) a crash event sensor158(for example, an inertia sensor or an accelerometer) including a known crash sensor algorithm that signals actuation of belt pretensioner156via, for example, activation of a pyrotechnic igniter (not shown) incorporated into the pretensioner. U.S. Pat. Nos. 6,505,790 and 6,419,177, previously incorporated herein by reference, provide illustrative examples of pretensioners actuated in such a manner.

The airbag embodiments described herein are preferably formed from known materials and by known processes. Exemplary suitable airbag materials and manufacturing methods are set forth in U.S. Pat. Nos. 6,632,753, 6,458,725 and 5,044,663 and U.S. patent application Publication Nos. 2003/0148683, 2003/0129339, 2003/0104226, 2003/0060103 and 20020155774. Each listed reference is hereby incorporated by reference in its entirety. For example, the airbag may be formed from a single panel of material folded over, joined, and sealed along mating edges to form an enclosure. Alternatively, the airbag may be formed from two or more separate panels of material joined and sealed along edges thereof. An inlet may be provided for insertion of a portion of a linear inflator into the airbag, to extend along a lengthwise edge of the airbag (for example, edge115ofFIG. 2). Alternatively, the airbag may be formed to enclose the inflator in the interior of the airbag, with a medium for transmission of an airbag actuation signal extending from an exterior of the airbag, through one or more of the constituent panels, and into the interior of the airbag to operatively communicate with, for example, an electrical circuit provided in the airbag inflator. The respective seams may be formed by any suitable known process. For example, in some instances it may be desirable to manually or mechanically sew stitches along the length of the seams. Alternative embodiments, for example utilizing a non-fabric or polymer coated fabric to form the airbag body, could employ heat sealing or ultrasonic welding to adhere the panels or sides of the airbag, thereby forming the seams. Still further contemplated embodiments use an adhesive.

Use of the seam patterns described herein in side airbag systems allows for improved air bag performance, particularly when used in conjunction with a linear inflator. Inflation of the airbag takes place in a more uniform manner, reducing the risk of localized overpressurization and seam bursting, and improving occupant protection. Moreover, the seam patterns disclosed herein are relatively simple, and their manufacture is relatively easy ands inexpensive.

It is contemplated that the present invention will find primary application in side impact or head curtain airbag systems; however, it is not limited thereto. It will also be understood that the foregoing description of an embodiment of the present invention is for illustrative purposes only. As such, the various structural and operational features herein disclosed are susceptible to a number of modifications commensurate with the abilities of one of ordinary skill in the art, none of which departs from the scope of the present invention as defined in the appended claims.