Patent Publication Number: US-11390239-B2

Title: Airbag, in particular for a side curtain airbag system, and vehicle safety system having such an airbag

Description:
RELATED APPLICATIONS 
     This application is a divisional application of U.S. application Ser. No. 16/311,838, filed Dec. 20, 2018, which corresponds to PCT/EP2017/066927, filed Jul. 5, 2017, which claims the benefit of German Application No. 10 2016 008 241.0, filed Jul. 7, 2016, the subject matter of each of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to an airbag, especially for a side curtain airbag system according to the preamble of claim  1 , as well as to a vehicle safety system equipped with such airbag according to the preamble of claim  10 . 
     Airbags for airbag systems, especially for side curtain airbag systems, have been known for some time. Airbag systems of this type serve for better protecting occupants of an automotive vehicle in the case of accident. For this purpose, a side curtain airbag system is arranged above a side window and in the case of crash deploys downwards in a curtain-like manner so as to better protect a head and shoulder area of a vehicle occupant against a side impact. 
     One drawback of these previously known side curtain airbag systems consists in the fact that they do not cover a thorax area of the vehicle occupant and a separate airbag (thorax airbag) has to be provided so as to obtain better protection also in the thorax area. 
     If the known side curtain airbag system was modified so that it would extend in the vertical direction further downwards, i.e. beyond the shoulder area and into an area on the side of the thorax of a vehicle occupant so as to protect in this way also the thorax area of a vehicle occupant by one airbag only for each vehicle occupant, a new problem would arise, namely a significantly larger airbag volume and, accordingly, the problem of managing a filling of such large airbag exactly in time and to the correct volume. This would be especially difficult, as the airbag is successively filled starting from the inflator provided for filling the airbag and being arranged either in a pillar or in the roof of a vehicle, wherein, according to the construction, at first the “curtain sections” of the airbag located further upwards and more closely to the gas supply are filled and only at last the section located further downwards which is provided for protecting the thorax is filled. 
     For this reason, in the past also airbag systems were suggested which protected the thorax area of a vehicle occupant with the aid of a second airbag. 
     However, it is a drawback of those airbag systems and, resp., airbags to fill the different airbag chambers or airbags in a way adapted in time so that the chambers or airbags are correctly filled and correctly positioned at the correct time for ensuring optimum occupant protection. 
     Airbag systems of this type are described, for example, in WO 2008/011414 A2, U.S. Pat. No. 7,350,804 B2 or US 2005/0134025 A1. 
     SUMMARY OF THE INVENTION 
     The object underlying the invention is to provide an airbag (for each vehicle occupant), especially for a side curtain airbag system, as well as a vehicle safety system being equipped with such airbag, while avoiding the afore-mentioned drawbacks, wherein the airbag volume is filled with gas in terms of time and space such that an optimized occupant protection is ensured. 
     This object is achieved by an airbag, especially for a side curtain airbag system, according to claim  1  as well as by a vehicle safety system according to claim  10  which is equipped with such airbag. 
     In particular, the object is achieved by an airbag, especially for a side curtain airbag system, wherein the airbag includes an airbag interior defining one single chamber in the deployed state of the airbag, the chamber having at least one gas guiding device by which the chamber is divided into at least one primary filling zone and at least one secondary filling zone. 
     It is a major point of the invention that, by way of the gas guiding device arranged inside the volume of the airbag within the airbag interior, a filling of the airbag volume controlled both as to space and as to time is possible starting from a fluid source, especially gas source, such as an inflator. For this purpose, the gas guiding device divides the airbag interior and, resp., the chamber of the airbag forming the airbag interior into at least one primary filling zone and into at least one secondary filling zone. 
     When gas is supplied into the airbag interior, the gas is thus guided along the gas guiding device first into the primary filling zone. A supply of gas into the secondary filling zone is substantially not carried out before a particular primary filling level is reached. 
     According to a preferred embodiment of the invention, the primary filling zone(s), i.e. at least one primary filling zone, is/are more distant in the spatial and fluidic respect from the single or at least one gas supply orifice through which gas supply of the airbag may take place, than the secondary filling zone(s) is/are distant from the respective same gas supply orifice. 
     In this context it is mentioned that the primary filling zone(s) according to a preferred embodiment of the invention is/are associated with the portion of the airbag that is provided for protecting the thorax, while the secondary filling zone(s) is/are associated with the, especially upper, “curtain section” of the airbag. 
     The gas guiding device according to the invention causes the respective primary filling zone(s) arranged spatially more distant from the gas supply orifice to have a smaller distance from the gas supply orifice in the fluidic respect than the respective secondary filling zone(s) has/have from the respective same gas supply orifice so that during filling the airbag according to the invention at first the primary filling zones and only afterwards the secondary filling zones are filled with gas. 
     In accordance with a preferred embodiment of the invention, this is effectuated in that the gas guiding device is configured so that it forms a separation, namely a separating device such as a separating wall or a separating seam between the primary filling zones and the secondary filling zones or, respectively, between the primary filling zone and the secondary filling zone. 
     The gas guiding device and, resp., the separating device is configured to be substantially impervious to gas for this purpose so that upon filling the airbag the gas flowing from the gas supply orifice into the airbag is guided along the separating device into the primary filling zone. The separating device thus delimits the primary filling zone against the secondary filling zone, wherein a complete, especially substantially gas-tight, separation of the two filling zones may be realized or a defined gas-permeable separation of the primary filling zone from the secondary filling zone is given so that a small portion of the inflowing gas along the separating device may flow through the same also into the secondary filling zone so that the latter is filled simultaneously with the primary filling zone, however by a definitely reduced volume flow. The reduced volume flow is within the range of 1% to 20%, preferably within the range of 2% to 15% and especially preferred within the range of 5% to 10%, each related to the inflowing total volume flow of the inflowing filling gas. 
     In accordance with an embodiment of the invention, the gas guiding device is formed in that at least two inner wall portions of the airbag facing each other and being associated with each other are interconnected directly or by means of a spacer, especially by means of a spacing belt, preferably in a detachable manner. The connection of the inner wall portions of the airbag associated with each other is realized, according to the invention, by means of a seam which may be a glued seam and/or a sealed seam and/or a stitched seam. In the case of use of a spacer, especially a spacer belt, the respective inner wall portions of the airbag are not connected directly but via the spacer belt, wherein the respective longitudinal sides and, resp., longitudinal edges of the spacer belt are again connected by means of a seam, which again may be a glued seam and/or a sealed seam and/or a stitched seam, to the pertaining, i.e. associated, inner wall portions of the airbag. 
     According to the invention, the spacer belt in turn may be configured to be gas-permeable or to have a defined gas permeability so that during a filling operation of the airbag according to the invention a main volume flow flows in the direction of the primary filling zone and a reduced secondary volume flow flows in the direction of the secondary filling zone. By the degree of gas permeability of the separating device a specific control in terms of time and space of the filling operation of the airbag according to the invention is possible, wherein the gas permeability of the separating device may be different over its length. At this point, also an initial gas permeability of the separating device, which is provided already at the beginning of the filling operation of the airbag, has to be distinguished from initiated gas permeability according to the invention which is resulting, for example, from a widening of pores or holes in the separating device during the filling operation. 
     In accordance with a preferred embodiment of the invention, the connection of the inner wall portions of the airbag associated with each other which forms the separation between the primary filling zone and the secondary filling zone is designed to be detachable so that the connection is released and, resp., opened upon increase in the internal pressure inside the airbag in the course of filling the airbag, for example, so that gas may flow through this releasing connection, i.e. opening separation, from the gas supply orifice and moreover from the primary filling zone into the secondary filling zone so that now also the secondary filling zone fills substantially completely with filling gas. In the case of using a spacer belt, a longitudinal edge of the belt may remain tightly connected to the associated inner wall of the airbag, while upon breaking of the connection the other longitudinal edge of the belt detaches from the associated inner wall portion of the airbag. 
     In accordance with the invention, the glued and/or sealed and/or stitched seam may have a different seam resistance. Such different seam resistance may be realized, for example, by a differently broad gluing and/or sealing and/or stitching. Moreover, also differently tight adhesives, sealing materials or yarns may be used. The respective types of connection may also be used in combination with each other and supplementing each other. 
     In addition, the seam may have at least one weakened portion serving as a predetermined breaking point for the seam. Such weakened portion may be in the form of a pointed seam, for example, which projects into the area of higher pressure during the filling operation of the airbag and peels and/or tears upon reaching a particular minimum pressure. By providing such weakened portion a breaking of the seam can advantageously be exactly controlled, wherein it is possible, for example, to define the point or points of the seam at which a breaking of the seam will be initiated or will start. 
     According to a further preferred embodiment of the invention, the gas guiding device is formed by a tubing system having at least one inlet opening and at least one outlet opening, the inlet opening being in fluid connection with the at least one gas supply orifice of the airbag and the at least one outlet opening ending in the primary filling zone of the chamber. According to the invention, it is advantageously possible to supply the filling fluid and, resp., gas to the volume of the airbag, i.e. the one or the plural primary filling zone(s) and the one or the plural secondary filling zone(s) through the tubing system so that at first the one or the plural primary filling zone(s) are filled with the filling fluid, as the outlet opening of the tubing system ends in the one or the respective primary filling zone(s) and only afterwards the gas flows via said primary filling zones into the secondary filling zone(s) of the airbag according to the invention and fills the latter. 
     According to the invention, the tubing system through which the gas is guided may be substantially completely gas-tight or may have a certain permeability for the inflowing gas so that a reduced volume flow may flow out of the tubing system directly into the one or the, possibly selected, secondary filling zone(s), wherein the reduced volume flow is in the range of from 1% to 20%, preferably in the range of from 2% to 15% and especially preferred in the range of from 5% to 10%, in each case related to the total volume flow of the inflowing filling gas. 
     In this way it is possible to fill both the primary filling zones and the secondary filling zones exactly at the desired time with the respectively desired amount of gas so that a filling targeted in terms of space and time of the airbag takes place. 
     Moreover, the tubing system may have a weakened point, for example in the form of a seam, which may be a sealed seam and/or a glued seam and/or a stitched seam, so that the tubing system will burst at one or more positions or else substantially completely when a predetermined filling state of the airbag is given. Such filling state of the airbag may be defined, for instance, via a predefined pressure prevailing in the primary filling zone and/or in the secondary filling zone and/or in the tubing system. It is stated in this context that also the airbag wall itself may be designed as part of the tubing system and may form part of the wall of the tubing system, for example. 
     For the rest, the tubing system may be guided along the inner wall of the airbag and/or be fastened on said inner wall, by means of spacers where necessary. 
     According to a further embodiment of the invention, the spacer, especially the spacer belt, and/or the tubing system is made substantially of the same material as the airbag. 
     Further the object according to the invention is achieved also by the use of an airbag for an airbag system, especially a side curtain airbag system, according to the foregoing remarks. 
     The object according to the invention is further achieved also by a method of filling an airbag, wherein gas is introduced into the airbag starting from a gas supply orifice using a gas guiding device according to the foregoing description, wherein before filling a secondary filling zone at first a primary filling zone is filled at least partly or substantially completely with gas. 
     In the course of feeding the secondary filling zone with gas, according to the invention, at least one separating device, especially at least one seam will be broken between the primary filling zone and the secondary filling zone of the chamber. The separation is substantially broken so far that the airbag interior in the deployed, i.e. in the substantially completely filled state of the airbag defines one single chamber. 
     Furthermore, the object according to the invention is also achieved by a vehicle safety system that is equipped with an airbag according to the foregoing description and is fed with gas by the afore-described method for filling such airbag. Such vehicle safety system includes at least one sensor unit for detecting data as well as an electronic decision-making unit which is adapted, while incorporating the data detected by the sensor unit, to define the presence of a trigger case for the airbag module and/or to send a trigger signal to the airbag module. 
     Summing up, the invention discloses a curtain airbag comprising a thorax protection, wherein the airbag has a specific airbag design according to the invention for quicker targeted and time-optimized deployment so as to optimally position the airbag for ensuring optimized occupant protection, especially in the case of side impact. The substantial aspect of the invention consists in the fact that the side curtain airbag including thorax protection is deployed so that the gas escaping from the propellant and possibly from a gas storage system is initially guided into the part of the airbag which is essential for the thorax protection, i.e. the lower part in the mounted and, resp., deployed state. According to an embodiment of the invention, this is obtained by way of a seam or plural seams and/or a tubing system arranged to be integrated in the airbag and serving as a gas guiding device. The seam or, respectively, the plural seams, is/are configured as regards their strength so that upon a predetermined degree of deployment and of the deployment volume of the airbag they will tear in the thorax area so that the gas may diffuse through the breaking point(s) of the seam also into the remaining volume of the airbag, which is substantially not associated with the thorax area of the airbag, and thus may substantially completely fill the airbag. This concept according to the invention may be applied to airbags having a thorax protection for one or more passenger rows. In accordance with the invention, the newly developed airbag is suited especially for vehicles having up to three rows of seats, with the airbag according to an embodiment of the invention being adapted to extend over all three rows of seats. In this case, it has turned out to be of advantage when the filling of the airbag is carried out substantially centrally with respect to the longitudinal extension of the airbag, i.e. an inflator is arranged substantially in the center of the longitudinal extension of the airbag. Alternatively, the airbag according to the invention may also extend over two passenger rows. Moreover, according to the invention it is possible to use a separate airbag for each seat row which may thus be used also in vehicles having two, three and more rows of seats such as a coach, for example. Especially the concept according to the invention is suited for airbags extending over one or two passenger rows. In this case, according to the invention there is preferred the combined design of an airbag according to the invention which extends jointly over the front seat row and the rear seat row. In this case, the inflator may be arranged either in the A-pillar, or in the B-pillar or C-pillar of the vehicle. According to an alternative embodiment, the use of individual airbags for the protection of the passengers in the front and rear seat rows is possible according to the invention. If the curtain airbag is provided for protecting the rear passengers of a vehicle, the inflator may be arranged, for example, in the C-pillar of the vehicle. Furthermore, the inflator/propellant utilized jointly with the novel airbag according to the invention can also be arranged at an angle, e.g. at an angle of preferably 90°, with respect to the deployment plane of the curtain airbag, i.e. in a roof plane of the vehicle, for example. Consequently, the novel airbag system according to the invention is especially suited for conventional sedans or station wagons having one or two rows of seats, but especially also for MPV, minivans, vans, pickups and coaches as well as trucks. 
     With the aid of the airbag design according to the invention, it is possible by all variants presented within the scope of this invention to eliminate any previous problems in deploying curtain airbag systems including a thorax protection in which the gas during deployment has been distributed in a non-directed manner starting from the inflator. Furthermore, the airbag design according to the invention offers the important and substantial advantage vis-à-vis previous single- and double-chamber systems for curtain airbags which have been utilized so far to provide a certain thorax protection that the deployment of the airbag according to the invention can be controlled by far better compared to said previous single- and double-chamber systems so that an airbag system equipped with such airbag according to the invention in a vehicle safety system in the case of crash offers protection for vehicle occupants which is definitely improved vis-à-vis conventional airbag systems. 
     The solution according to the invention is based on the fact that the gas flowing out of the inflator or, resp., propellant at first flows directly into the thorax area of the airbag according to the invention until said thorax area has a particular predetermined degree of deployment. At this time the thorax area of a vehicle occupant is thus protected extremely quickly. When the thorax area of the airbag has reached a predetermined degree of deployment, the seam(s) provided with predetermined breaking points tear(s) and the other areas of the volume of the airbag will fill step-by-step with filling gas in a controlled manner. 
     Hence it can be exactly defined by the airbag design according to the invention which areas of the airbag are filled with filling gas in which order of time and space. 
     According to a further variant according to the invention, the gas guiding device cannot only be designed in the form of one seam or plural seams being placed inside the airbag, but such gas guiding device can also be present, as mentioned before, as a tubing system extending inside the airbag and serving for distribution of the filling gas in the airbag. For this purpose, the tubing system is connected, on the one hand, to a gas supply means such as an inflator and, on the other hand, extends with at least one open end into a portion of the airbag provided for the thorax protection. The tubing system for this purpose may have branches, for example to fill the respective airbag areas for the side curtain airbag system, which are provided for several passenger rows, or to fill plural primary filling zones in a portion of the airbag which are associated with only one seat row. In this context, it is also possible to feed a primary filling zone of the airbag according to the invention of two, for instance opposed, airbag portions with filling gas. Equally it is provided according to the invention that in an airbag according to the invention two primary filling zones are provided one of which protects the thorax and another one protects the head area. 
     Furthermore, the tubing system can be configured so that the filling gas is guided through the tube initially into the respective portions of the airbag provided for the thorax protection and then starting from these portions extends into the residual volume of the airbag. In accordance with a variant according to the invention of such tubing system, the latter may also be formed so that the gas guiding tube tears upon certain deployment of the airbag at one or more positions so that gas can escape from the gas guiding tube and can fill the residual airbag volume. A delimitation of the gas guiding tube may be formed, for example, by one or more seams resulting from the fact that inner walls of the airbag are interconnected in accordance with a gas guiding device. This seam may have predefined seam characteristics and may be configured so that it will burst in the case of a predefined inflating and, resp., deployment volume of the airbag. 
     An airbag according to the invention thus cannot only be filled in a well-defined manner from the bottom to the top, i.e. in the vertical direction, but also from the front to the back, i.e. in the horizontal direction so that, as desired, a back area of a vehicle occupant or an abdominal area of the vehicle occupant is protected in a specific manner primarily, i.e. more quickly, or secondarily, i.e. subordinately. In this respect, the airbag according to the invention may be selected to be specifically combined for a respective vehicle and its driver with consideration of his/her figure and mounted into the vehicle. 
     Moreover, the invention relates to an aspect of using an airbag according to the foregoing remarks for an airbag system, especially a side curtain airbag system, as well as a method aspect for filling an airbag, wherein starting from a gas supply orifice gas is introduced into the airbag using a gas guiding device according to the foregoing description, wherein prior to feeding a secondary filling zone at first one or several primary filling zone(s) is/are filled substantially completely with gas. 
     According to an embodiment of the method, in the course of feeding the secondary filling zone with gas at least one separation, especially at least one seam and/or one tube, is broken between the primary filling zone and the secondary filling zone of the chamber. 
     According to the invention, the separation is broken so far that the airbag interior defines one single chamber in the deployed, i.e. substantially completely filled state of the airbag. 
     The advantages of the airbag and, respectively, airbag system according to the invention thus can be summarized as follows. By way of the airbag design according to the invention it is possible to fill a single-, double- or multi-row airbag very quickly so that the thorax area of a vehicle occupant is protected in an extremely rapid manner. The deployment of the airbag according to the invention is more targeted as compared to airbags known from the state of the art, namely in terms of both time and space. Due to the configuration of the airbag according to the invention as a single-chamber system, both the deployment and the filling of the airbag according to the invention is optimized vis-à-vis previously known airbags. If the airbag according to the invention is in the form of a single-row airbag, it is moreover possible to position any number of said airbags, for example in a coach, one behind the other, wherein each of said airbags offers the advantages according to the invention. These include, inter alia, the possibility of using a small inflator which results in a lower weight of the airbag system. This is advantageous especially with respect to previous curtain airbag systems which required a second airbag for a thorax protection. 
     Further embodiments of the invention will be resulting from the subclaims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Hereinafter the invention will be described by way of embodiments which will be explained in detail by way of the pictures, in which: 
         FIGS. 1 a  to 1 d    show state-of-the-art airbag systems in a schematic representation; 
         FIG. 2  shows a first embodiment of an airbag according to the invention in a schematic sectional view; 
         FIG. 3  shows a second embodiment of an airbag according to the invention in a schematic sectional view; 
         FIG. 4  shows a third embodiment of an airbag according to the invention in a schematic sectional view; 
         FIG. 5  shows a fourth embodiment of an airbag according to the invention in a schematic sectional view; 
         FIG. 6  shows a fifth embodiment of an airbag according to the invention in a schematic sectional view; 
         FIGS. 7 a  to 7 f    show a schematic representation of an airbag according to the invention in a sectional view having differently arranged gas supply orifices and inflators in accordance with a further embodiment of the invention; 
         FIGS. 8 a  to 8 f    show a schematic representation of an airbag according to the invention in a sectional view having differently arranged gas supply orifices and inflators according to a further embodiment of the invention; 
         FIGS. 9 a  to 9 f    show a schematic representation of an airbag according to the invention in a sectional view having differently arranged gas supply orifices and inflators according to a further embodiment of the invention; and 
         FIGS. 10 a  to 10 f    show a schematic representation of an airbag according to the invention in a sectional view having differently arranged gas supply orifices and inflators according to a further embodiment of the invention. 
     
    
    
     DESCRIPTION 
       FIGS. 1 a  to 1 d    show airbag systems  20  known from the state of the art having no thorax protection or a thorax protection insufficient especially for children. The airbag system  20  according to  FIG. 1 a    is designed merely for the respective front seats, while the airbag system  20  according to  FIG. 1 b    extends over the rear and front seat rows, wherein in both cases no thorax protection is ensured, however, as these side curtain airbag systems  20  do not extend sufficiently far downwards. This applies mutatis mutandis to the side curtain airbag system  20  according to  FIG. 1 c    which, although including a small separate airbag for each of the rear and front seat rows which offers protection for the pelvis and the thighs, again does not ensure any thorax protection. Although the side curtain airbag system  20  according to  FIG. 1 d    known from the state of the art offers thorax protection for the back seats, wherein the part of that airbag system  20  provided for the back seats includes a double-chamber system, also this side curtain airbag system  20  does not exhibit any thorax protection for the respective front seats, however. 
     The embodiments of  FIGS. 2-10F  achieve objects of the invention by way of an airbag  10 , especially for a side curtain airbag system  20 , wherein the airbag includes an airbag interior  30  defining one single chamber  40  in the deployed state of the airbag, the chamber having at least one gas guiding device  50  by which the chamber is divided into at least one primary filling zone  41  and at least one secondary filling zone  42 . 
     In accordance with a preferred embodiment of the invention, this is effectuated in that the gas guiding device  50  is configured so that it forms a separation, namely a separating device such as a separating wall or a separating seam between the primary filling zones  41  and the secondary filling zones  42  or, respectively, between the primary filling zone  41  and the secondary filling zone  42 . 
     The gas guiding device  50  is formed in that at least two inner wall portions  12  of the airbag  10  facing each other and being associated with each other are interconnected directly by a seam  52  or by means of a spacer, especially by means of a spacer belt  53 , preferably in a detachable manner. 
     The connection of the inner wall portions  12  of the airbag  10  associated with each other is realized, according to the invention, by means of the seam  52  which may be a glued seam and/or a sealed seam and/or a stitched seam. In the case of use of the spacer belt  53 , the respective inner wall portions  12  of the airbag  10  are not connected directly but via the spacer belt, wherein the respective longitudinal sides and, respectively, longitudinal edges of the spacer belt  53  are again connected by means of seams, which again may be a glued seam and/or a sealed seam and/or a stitched seam, to the pertaining, i.e., associated, inner wall portions of the airbag. 
       FIG. 2  illustrates a first embodiment of an airbag  10  according to the invention in a schematic sectional view. The airbag  10  comprises an airbag interior  30  including a chamber  40  which is divided into a primary filling zone  41  and a secondary filling zone  42  by a gas guiding device  50  in the form of a seam  52 . The airbag  10  includes a gas supply orifice  60  connected to an inflator or any other gas supply means. Through said gas supply orifice  60  filling gas flows into the airbag interior  30  in the operating state of the airbag  10  and spreads along the initial gas flow direction  90  at first non-directed into the gas interior  30 , but is guided immediately afterwards by the gas guiding device  50  in the form of a seam  52  along the primary gas flow direction  100  represented as a bold straight arrow into the primary filling zone  41 . This primary filling zone  41  deploys, according to the invention, up to a predefined degree, wherein upon reaching such degree and an accompanying predefined deployment volume bursting of the seam  52  is initiated, which seam then tears at least partly or completely and enables a secondary gas flow direction  200  represented as a bold curved arrow along which the secondary filling zones  42  of the airbag  10  are filled. Thus the airbag  10  according to the invention of  FIG. 2  is filled at first in its primary filling zone  41  represented at the bottom of the picture. This primary filling zone  41  substantially serves for the protection of a thorax area of a vehicle occupant, but it can also be continued up to the pelvis and thigh area, if desired. As is evident from  FIG. 2 , that airbag is formed for two seat rows, wherein the gas supply orifice  60  and the inflator are arranged in the rear part of the airbag  10  and are accommodated in the C-pillar of the vehicle. 
       FIG. 3  illustrates a second embodiment of an airbag  10  according to the invention in a schematic sectional view substantially corresponding to the embodiment shown in  FIG. 2 , with the difference that the airbag  10  according to  FIG. 3  is not filled from behind, i.e. starting from the C-pillar of the vehicle, but centrally, i.e. starting from the B-pillar of the vehicle, with filling gas. This embodiment offers the advantage of filling gas being adapted to flow uniformly into the portion of the airbag  10  associated with the front seat row and the rear seat row due to gas entry in the central area of the airbag  10 . According to  FIG. 3 , too, the filling gas initially flows along a primary gas flow direction  100  first into a primary filling zone  41  of the airbag interior  30 , which again and corresponding to  FIG. 2  is designed as one single chamber, and only after bursting of the gas guiding device  50  in the form of a seam  52  it flows into the secondary filling zone  42 . 
       FIG. 4  shows a third embodiment of an airbag  10  according to the invention in a schematic sectional view, wherein the gas supply orifice  60  is arranged again in the rear area of the airbag  10 . In this context, it is emphasized that the gas supply orifice  60  basically cannot only be arranged in the rear area of the airbag  10  and, resp., in the central area of the airbag, but on principle may also be arranged in the front area of the airbag  10 , namely whenever the inflator and, resp., the gas supply means, is not intended to be provided in the C-pillar or the B-pillar but in the A-pillar of the vehicle. It is basically also possible to accommodate the inflator in the roof area of the vehicle and to design a gas supply orifice  60  on the airbag according to the invention corresponding to the desired arrangement of the inflator. 
     According to  FIG. 4 , the filling gas flows along an initial gas admission direction  90  through the gas supply orifice  60  into the airbag interior  30  which is in the form of one single chamber  40 . The gas initially enters into a tubing system  54  which is formed by providing, on the one hand, a tube section of the tubing system  54  tightly arranged on the inlet opening  55  for the filling gas which interacts with a seam  52  interconnecting the inner wall sides of the chamber  40  of the airbag interior  30 . The interaction between the tube section and the seam  52  results in a tubing system  54  which at its lower end includes an outlet opening  56  through which the filling gas may flow, upon filling the side curtain airbag system  20 , along a primary gas flow direction  100  into the primary filling zone  41  of the airbag  10 . After the primary filling zone  41  of the airbag  10  has widened and deployed up to a predefined degree, the seam  52  bursts along the predetermined breaking point  57  and enables the filling gas to flow along the secondary gas flow direction  200  into the secondary filling zone  42  of the airbag  10 . 
       FIG. 5  illustrates a fourth embodiment of an airbag  10  according to the invention in a schematic side view, wherein again a gas supply orifice  60  connected to an inflator is provided in the rear part of the airbag  10 . Through the gas supply orifice  60  gas flows along an initial gas flow direction  90  through an inlet opening  55  into a tubing system  54  which extends in the interior  30  of the airbag  10 . The airbag  10  according to  FIG. 5  is an airbag for two seat rows. According to  FIG. 5 , the tubing system  54  extends starting from the inlet opening  55  into the thorax protection zone for each of the front and rear seat rows and there includes respective outlet openings  56  through which the filling gas can flow along a primary gas flow direction  100  into the respective primary filling zone  41 . After the filling gas has escaped from the respective outlet opening  56 , the filling gas initially spreads in the primary filling zone  41  and from there subsequently flows into the secondary filling zone  42  of the side curtain airbag system  20 . 
       FIG. 6  shows another, i.e. fifth embodiment of an airbag  10  according to the invention in a schematic sectional view, wherein a tubing system  54  is provided through which filling gas is guided from an inlet opening  55  to two respective outlet openings  56  in the respective primary filling zones  41  of the airbag  10  which are associated with a respective thorax protection zone for a front and a rear seat row of the side curtain airbag system  20 . Also in this case, the filling gas initially flows through the outlet openings  56  into the respective primary filling zone  41  and only afterwards, i.e. only after the primary filling zone  41  has been filled at least partly, into the secondary filling zone  42  of the airbag  10 . 
     Each of the airbags  10  schematically shown in  FIGS. 7 a  to 10 f    are formed as single-row airbags  10 , wherein the respective pictures inter alia differ by the fact that the schematically shown airbags  10  designated with a and b in the pictures include a gas supply orifice  60  which in the driving and mounting direction is formed and arranged at the front, whereas the airbags  10  designated with the letters c and d include a gas supply orifice  60  which in the driving and mounting direction is formed and arranged centrally, and the airbags  10  designated with the letters e and f include a gas supply orifice  60  which in the driving and mounting direction is formed on the rear side. An inflator is associated with each of the gas supply orifices  60 . 
     According to  FIGS. 7 a  to 10 f   , the filling gas flows along an initial gas admission direction  90  through the gas supply orifice  60  into the airbag interior  30  which is in the form of one single chamber  40 . 
     In each of the  FIGS. 7 a  to 7 f    an airbag according to the invention is shown in a respective schematic sectional view, wherein filling gas flows through a gas supply orifice  60  into a tubing system  54  arranged within the airbag  10  that serves as a gas guiding device  50 . According to  FIGS. 7 a , 7 b , 7 e  and 7 f   , the tubing system  54  includes two outlet openings  56  through which in the operating state, i.e. during a filling operation of the airbag  10 , the filling gas flows initially into two primary filling zones  41  associated with the thorax area and the head area so that, in a case of crash, first the thorax area as well as the head area of a vehicle occupant are protected. In the case of a central filling of the airbag  10  according to the invention, as schematically shown in  FIG. 7 c    and  FIG. 7 d   , the tubing system  54  arranged in the airbag  10  includes a total of three outlet openings  56  through which the filling gas can initially flow into the primary filling zones  41  of the airbag  10  according to the invention. A filling of the secondary filling zones  42  does not take place before the filling gas has flown along the primary gas flow direction  100  into the primary filling zone  41  and from there outpours into the secondary filling zones  42 . 
     The embodiment of an airbag according to the invention shown in  FIGS. 9 a  to 9 f    substantially differs from the embodiment shown in  FIGS. 7 a  to 7 f    in that the airbag according to the invention as illustrated in  FIGS. 9 a  to 9 f    includes a tubing system  54  which has only one single outlet opening  56  which is associated with the primary filling zone  41  and with the thorax area. According to this embodiment, the filling gas flows from the gas supply orifice  60  into the tubing system  54  and leaves the latter along a primary gas flow direction  100  through the outlet opening  56 , wherein the first filling zone  41  of the airbag  10  is inflated and thus deployed. After the fill volume of the airbag  10  has reached a predefined level in the first filling zone  41 , the filling gas flows into the secondary filling zone(s)  42  along a secondary gas flow direction  200 . 
     According to  FIGS. 8 a  to 8 f   , the airbag  10  according to the invention includes a gas guiding device  50  which in the case of front-side or rear-side filling is configured as a seam  52  and in the case of central filling is configured as two seams  52  defining a channel. Along the gas guiding device  50  the flowing filling gas is guided along a primary gas flow direction  100  first into the first filling zone  41 , until the latter has a predetermined fill volume as well as a predetermined pressure. Upon reaching said fill volume and/or the predetermined pressure, the gas guiding device  50  in the form of a seam  52  will tear so that the filling gas can flow along the secondary gas flow direction  200  into the secondary filling zone  42 . In this way, the filling gas inflowing from the gas supply orifice  60  at first along an undefined initial gas admission direction  90  does not spread in the airbag  10  according to the invention in a non-directed and turbulent manner, as in the previous state of the art, but flows along the gas guiding device  50  in a directed manner first into the primary filling zone  41  and only afterwards into the secondary filling zone  41 . As is indicated in  FIGS. 8 a  to 8 f    by the hatched seam  52 , according to the invention the seam  52  is not designed to be completely gas-tight but permits a minor gas passage, when the outflowing filling gas flows along the gas guiding device  50 . In this way, the secondary filling zone  42  can slightly deploy already before the seam  52  bursts, which, on the one hand, contributes to improved deployment of the curtain airbag per se as well as to controlled inflation of the secondary filling zone  42  after filling the first filling zone  41 . 
     In  FIGS. 10 a  to 10 f    another embodiment of an airbag  10  according to the invention is illustrated in a schematic sectional view in which the filling gas coming from the gas supply orifice  60  flows into a tubing system  54  formed of seams  52  that may burst at a predefined pressure. In accordance with the embodiments shown in  FIGS. 10 a  to 10 f    it is illustrated in which way a tubing system  54  can be formed of seams  52 , wherein the tubing system  54  will tear from a particular fill volume of the airbag  10  and, resp., of the primary filling zone thereof by bursting of the seams  52  so that the inflowing filling gas then does not only flow along a primary gas flow direction  100  through the outlet opening  56  but also outpours through the burst seams  52  into the secondary filling zone(s)  42 . The respective gas flow directions are schematically indicated in  FIGS. 7 a  to 10 f    by respective arrows. 
     Each of the airbags  10  according to the invention schematically represented in  FIGS. 2 to 10   f  is provided with module fastenings  1  and a strap or belt  2  which serve for mounting the respective airbags  10  on or in a vehicle. 
     It is pointed out in this context that all afore-described parts considered per se and in any combination, especially the details shown in the drawings, are claimed to be essential to the invention. Modifications of the same are known to those skilled in the art. 
     LIST OF REFERENCE NUMERALS 
     
         
           1  module fastening 
           2  strap or belt 
           10  airbag 
           20  side curtain airbag system 
           30  airbag interior 
           40  chamber 
           41  primary filling zone 
           42  secondary filling zone 
           50  gas guiding device 
           52  seam 
           54  tubing system 
           55  inlet opening 
           56  outlet opening 
           57  predetermined breaking point 
           60  gas supply orifice 
           90  initial gas admission direction 
           100  primary gas flow direction 
           200  secondary gas flow direction