Abstract:
An airbag apparatus for a vehicle with three seat-rows includes a vehicle airbag having first and second sections independent from each other extending in the longitudinal direction. The second section includes a first chamber, a second chamber and one gas inlet for supply gas to the second section. The first and second chambers are separated from each other in the longitudinal direction with a space therebetween except upper ends thereof through which the first and second chambers directly communicate with each other. The first section, first chamber and second chamber extend continuously along an upper portion of a sidewall of the vehicle and are located at portions corresponding to the three seat-rows of the vehicle to protect the passengers in the three seat-rows, respectively.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This is a continuation application of Ser. No. 11/017,006 filed on Dec. 21, 2004. 
     
    
     BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT 
       [0002]    The present invention relates to an airbag apparatus installed in a vehicle such as an automobile. More specifically, the present invention relates to an airbag apparatus for preventing a passenger from colliding against a sidewall of a vehicle in an accident such as a side collision or roll-over. 
         [0003]    There have been proposed various airbag apparatus for protecting a passenger from colliding into a sidewall of a vehicle such as a side window and door upon a vehicle accident such as a side collision or roll-over. For example, an airbag apparatus including a vehicle airbag stored along a side roof rail of an automobile has been proposed (for example, refer to Japanese Patent Publication (Kokai) No. 2001-328504). 
         [0004]    Japanese Patent Publication (Kokai) No. 2001-328504 has disclosed a technology for reliably inflating an airbag in a vehicle having two rows of seats. However, for a large vehicle having at least three rows of seats, it is necessary to improve the technology so that a sufficiently large airbag can be inflated quickly and reliably in a passenger-protection region between a sidewall of the vehicle and a passenger. 
         [0005]    In view of the problems mentioned above, an object of the present invention is to provide an airbag apparatus for safely protecting a passenger upon a vehicle accident. 
         [0006]    Further objects and advantages of the invention will be apparent from the following description of the invention. 
       SUMMARY OF THE INVENTION 
       [0007]    In order to attain the objects described above, according to the present invention, an airbag apparatus can be installed in various vehicles having a three-seat-row arrangement such as an automobile, train, and marine vessel. In such a vehicle, the three-seat-row arrangement may be a standard configuration or arranged as an option. 
         [0008]    According to a first aspect of the present invention, an airbag apparatus is installed in a vehicle having a three-seat-row arrangement, and comprises a vehicle airbag having a plurality of sections and a gas supplying device. The vehicle airbag is installed in an upper sidewall of the vehicle, and inflated downwardly in a passenger-protection region between a passenger in a seat and a sidewall of the vehicle for protecting the passenger upon an accident such as a side collision or roll-over. The gas supplying device such as an inflator is capable of generating an inflation gas for inflating the airbag. The sidewall includes a member constituting a large area on a side of the vehicle at a left or right side of the passenger such as a side window or a door. The vehicle airbag is typically installed in an area between a side roof panel at an upper region of the sidewall and a ceiling panel. 
         [0009]    In the first aspect of the present invention, the vehicle airbag includes a plurality of independent sections separating an inside of the airbag. The gas supplying device individually supplies gas to each section for inflating the airbag. That is, the gas supplying device is activated upon a vehicle collision for individually supplying gas to each section. The vehicle airbag may include one airbag having a plurality of sections or a plurality of airbags each having a plurality of sections. The gas supplying device may comprise a plurality of gas supplying devices corresponding to the sections of the airbag and disposed apart from each other. A plurality of gas supplying devices may be provided as a unit. A housing may be provided for retaining a plurality of independent gas-generating mechanisms. 
         [0010]    In the first aspect of the present invention, the vehicle airbag may have a section to be inflated in a passenger-protection region corresponding to at least a third seat-row. Accordingly, a predetermined section of the vehicle airbag is inflated across a plurality of passenger-protection regions including the passenger-protection region corresponding to the third seat-row. 
         [0011]    In the first aspect of the airbag apparatus, the airbag can be inflated quickly and reliably even when the airbag has a large size and a large inflation volume suitable for a large vehicle having the three-seat-row arrangement. More specifically, in a large vehicle capable of having at least the three-seat row arrangement, an airbag needs to have a large size and volume as opposed to an airbag for a small vehicle having just a two-seat row arrangement. Accordingly, an airbag for a large vehicle needs to be quickly and reliably inflated. In the first aspect of the present invention, the airbag of the airbag apparatus is divided into a plurality of independent sections. Furthermore, the gas supplying device individually supplies gas to each section. Accordingly, it is possible to quickly supply gas to each section even when the airbag has a large size and large volume. Moreover, it is possible to reliably supply gas to a plurality of sections in comparison with a case in which a single gas generating device supplies gas to each section. 
         [0012]    An inside of the airbag may be divided into various shapes. For example, in a vehicle capable of having the three-seat-row arrangement, the inside of the airbag may be divided into three sections corresponding to each of the three seat-rows (total of three sections). Alternatively, the airbag may be divided into one section corresponding to one seat-row and one section corresponding to two other seat-rows (total of two sections). Further, the airbag may be divided into one section corresponding to the first and second seat-rows, and one section corresponding to the second and third seat-rows (total of two sections). 
         [0013]    According to a second aspect of the present invention, in the airbag apparatus of the first aspect, the airbag has a section to be inflated in a passenger-protection region corresponding to a plurality of seat-rows. 
         [0014]    In the airbag apparatus of the second aspect, the section of the airbag is inflated across a plurality of passenger-protection regions, thereby making a structure simple. The airbag has a section corresponding to the third seat-row as well as a plurality of passenger-protection regions. The airbag may have a section corresponding to seat-rows other than the third seat-row as well as a plurality of passenger-protection regions. In other words, the section to be inflated in the passenger-protection region corresponding to the third seat-row is inflated across a plurality of seat-rows including the third seat-row. Alternatively, the section to be inflated in the passenger-protection region corresponding to the seat-rows other than the third seat-row may be inflated across a plurality of seat-rows including the seat-rows other than the third seat-row. 
         [0015]    According to a third aspect of the present invention, in the airbag apparatus of the first or second aspect, the airbag may have a plurality (at least two) of sections to be inflated so that the inflated sections overlap in the passenger-protection region corresponding to a predetermined seat-row. For example, when the airbag is inflated, two sections overlap vertically or horizontally in a passenger-protection region corresponding to the second seat-row. In this case, the sections may entirely or partially overlap each other. In the airbag apparatus of the third aspect, it is possible to reliably protect a passenger seated in the predetermined seat-row with the inflated sections. 
         [0016]    According to a fourth aspect of the present invention, in the airbag apparatus of one of the first to third aspects, the airbag may extend continuously from a region corresponding to the first seat-row to at least the region corresponding to the third seat-row over the upper portion of the sidewall. Typically, in a vehicle capable of having a three-seat-row arrangement, the vehicle airbag is arranged to extend continuously from an A pillar to a B pillar (front intermediate pillar), i.e. the region corresponding to the first seat-row, and to a D pillar through a C pillar (rear intermediate pillar), i.e. the region corresponding to the third seat-row. 
         [0017]    In the airbag apparatus of the fourth aspect, the airbag is arranged to extend continuously from a region corresponding to the first seat-row to a region corresponding to at least the third seat-row, and is inflated at once in the passenger-protection regions corresponding to each seat-row. Accordingly, as compared with a case wherein an airbag does not extend continuously from the region corresponding to the first seat-row to the region corresponding to at least the third seat-row, it is possible to inflate and deploy the airbag in the passenger-protection region without a delay in timing. 
         [0018]    According to a fifth aspect of the present invention, an airbag apparatus is installed in a vehicle capable of having a three-seat-row arrangement and includes at least a vehicle airbag having a plurality of sections and gas supplying device. The airbag apparatus includes a first section and a second section separating an inside of the vehicle airbag into independent sections; first gas supplying device capable of individually supplying inflation gas to the first section; and second gas supplying device capable of individually supplying inflation gas to the second section. In particular, the vehicle airbag continuously extends over an upper portion of the sidewall from a region corresponding to the first seat-row to a region corresponding to the third seat-row. When the vehicle airbag is inflated, the first and second sections overlap each other in a passenger-protection region corresponding to the second seat-row. 
         [0019]    In the airbag apparatus of the fifth aspect, the airbag can be quickly and reliably inflated even when the airbag has a large size and volume suitable for a large vehicle capable of having a three-seat-row arrangement. A passenger in the second seat-row can be reliably protected with the inflated first and second sections. The vehicle airbag extends continuously from the region corresponding to the first seat-row to the region corresponding to the third seat-row. Accordingly, as compared with a case wherein a vehicle airbag does not extend from the region corresponding to the first seat-row to the region corresponding to the third seat-row, it is possible to inflate and deploy the airbag in the passenger-protection region without a delay in timing. 
         [0020]    As described above, according to the present invention, the airbag apparatus comprises a plurality of the independent sections separating the inside of the vehicle airbag and the gas supplying device for individually supplying inflation gas to the sections. A predetermined section is inflated in a passenger-protection region corresponding to at least the third seat-row. Accordingly, with the airbag apparatus, it is possible to safely protect a passenger in a large vehicle capable of having at least a three-seat-row arrangement during an accident. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a schematic view of an airbag apparatus disposed in a vehicle according to an embodiment of the present invention; 
           [0022]      FIG. 2  is a partial cross-sectional view of a B-pillar taken along line  2 - 2  in  FIG. 1 ; 
           [0023]      FIG. 3  is a view showing a structure of the airbag apparatus shown in  FIG. 2  and an airbag in an inflated state. 
           [0024]      FIG. 4  is a view showing the airbag shown in  FIG. 3  seen from a front side of a vehicle when the airbag is completely inflated; 
           [0025]      FIG. 5  is a view showing the airbag shown in  FIG. 3  seen from a side of the vehicle when the airbag is completely inflated; 
           [0026]      FIG. 6  is a schematic view showing a structure of an airbag apparatus according to another embodiment of the present invention; 
           [0027]      FIG. 7  is a schematic view showing a structure of an airbag apparatus according to a further embodiment of the present invention; and 
           [0028]      FIG. 8  is a schematic view showing a structure of an airbag apparatus according to a still further embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0029]    Hereunder, embodiments of the present invention will be described with reference to the accompanying drawings. A structure and operation of an airbag apparatus  100  according to an embodiment of the present invention will be described with reference to  FIGS. 1 to 5 . The airbag apparatus  100  shown in  FIG. 1 to 5  is installed on a right side of a vehicle to protect a passenger seated on the right side of the vehicle. 
         [0030]      FIG. 1  is a schematic view of the airbag apparatus  100  installed in the vehicle according to the embodiment.  FIG. 2  is a partial cross-sectional view of a B-pillar  14  taken along line  2 - 2  in  FIG. 1 . The airbag apparatus  100  shown in  FIG. 2  is in an initial state before being operated.  FIG. 3  is a view showing a structure of the airbag apparatus  100  shown in  FIG. 2  and an airbag  120  in an inflated state. In  FIGS. 1 and 3 , a left direction is a direction toward a front side of the vehicle and a right direction is a direction toward a rear side of the vehicle.  FIG. 2  is a view showing a right sidewall of the vehicle, wherein a right direction is a direction toward an inside of the vehicle and a left direction is a direction toward an outside of the vehicle. 
         [0031]    As shown in  FIG. 1 , the vehicle (automobile) in which the airbag apparatus  100  is installed is capable of having a three-seat-row arrangement. More specifically, the automobile includes a first seat-row (a first seat) S 1 , a second seat-row (a second seat) S 2 , and a third seat-row (a third seat) S 3 . In each of the seat-rows, one or more passengers C can be seated. The automobile may have three fixed seat-rows, or the seats may be arranged in the three seat-row arrangement as an option. 
         [0032]    As shown in  FIGS. 1 and 2 , the airbag apparatus  100  is disposed above a side window  10  in a space  20  defined by a ceiling panel  15  and a right-side roof rail (vehicle panel)  19 . The airbag apparatus  100  is disposed along a direction that the right-side roof rail  19  extends through an A pillar  12 , a B pillar (a front intermediate pillar)  14 , a C pillar (a rear intermediate pillar)  16 , and a D pillar  18 . More specifically, the airbag apparatus  100  includes the airbag  120  (described below) and inflators  111  and  112 , and extends continuously over an upper region of a sidewall from a region corresponding to the first seat-row S 1  between the A pillar  12  and the B pillar  14  to a region corresponding to the third seat-row S 3  between the C pillar  16  and the D pillar  18 . 
         [0033]    The airbag apparatus  100  quickly and reliably protects the passengers upon a vehicle accident such as a side collision or roll-over. The airbag apparatus  100  includes a vehicle airbag stored in a predetermined folded form (bellows or a roll) and inflators (gas generating units) capable of generating and supplying gas into an inner space of the airbag. In the embodiment, as shown in  FIG. 3 , the airbag apparatus  100  mainly includes the single airbag  120  formed in a bag shape, the first inflator  111  and the second inflator  112  for supplying gas to the airbag  120 , and a plurality of brackets  125  for fixing the airbag  120  to the roof rail  19  on the right side. 
         [0034]    As shown in  FIG. 3 , the airbag  120  corresponds to a vehicle airbag in the present invention. An inner space of the airbag  120  is individually divided into a front inflatable part  123  and a rear inflatable part  124  with stitches  120   a  indicated as hidden lines in  FIG. 3 . The front inflatable part  123  and the rear inflatable part  124  are independent regions formed by sectioning the inside of the airbag  120 . In the present invention, the front inflatable part  123  corresponds to a section or a first section, and the rear inflatable part  124  corresponds to a section or a second section. 
         [0035]    In the airbag  120 , the first inflator  111  is connected to the front inflatable part  123 , and the second inflator  112  is connected to the rear inflatable part  124 . More specifically, the first inflator  111  independently supplies inflation gas to the front inflatable part  123 . The inflation gas is independently supplied to the front inflatable part  123  via a first inlet  121  facing the rear side of the vehicle. The second inflator  112  independently supplies inflation gas to the rear inflatable part  124 . The inflation gas is independently supplied to the rear inflatable part  124  via a second inlet  122  facing the rear ride of the vehicle. In the embodiment, the inflators  111  and  112  are disposed so as to be apart from each other. The first inflator  111  corresponds to a gas supplying device or a first gas supplying device, and the second inflator  112  corresponds to a gas supplying device or a second gas supplying device. 
         [0036]    The front inflatable part  123  of the airbag  120  includes a first inflatable chamber  123   a  and a second inflatable chamber  123   b . The first inflatable chamber  123   a  is to be inflated in an area corresponding to a passenger-protection region P 1  of the passenger C seated in the first seat-row (the first seat-row S 1  shown in  FIG. 1 ). The second inflatable chamber  123   b  is to be inflated in an area corresponding to a passenger-protection region P 2  of the passenger C seated in the second seat-row (the second seat-row S 2  shown in  FIG. 1 ). The rear inflatable part  124  of the airbag  120  includes a third inflatable chamber  124   a  and a fourth inflatable chamber  124   b . The third inflatable chamber  124   a  is to be inflated in an area corresponding to a passenger-protection region P 2  of the passenger C seated in the second seat-row (the second seat-row S 2  shown in  FIG. 1 ). The fourth inflatable chamber  124   b  is to be inflated in an area corresponding to a passenger-protection region P 3  of the passenger C seated in the third seat-row (the third seat-row S 3  shown in  FIG. 1 ). The passenger-protection regions P 1 , P 2 , and P 3  are formed between the passengers C and the sidewall of the vehicle. The passenger-protection regions P 1 , P 2 , and P 3  are protection regions for protecting at least heads of the passengers C. In the present invention, the passenger-protection regions P 1 , P 2 , and P 3  correspond to the passenger-protection regions. 
         [0037]    In the embodiment, the third inflatable chamber  124   a  is disposed below the second inflatable chamber  123   b , so that the inflatable chambers  124   a  and  123   b  overlap each other. The second inflatable chamber  123   b  is inflated in the upper portion of the passenger-protection region P 2  for the passenger C in the second seat-row S 2 , and the third inflatable chamber  124   a  is inflated in the lower portion of the passenger-protection region P 2 . In other words, the airbag  120  includes the front inflatable part  123  and the rear inflatable part  124  partially overlapping each other in the vertical direction when inflated. 
         [0038]    An operation of the airbag apparatus  100  having the structure described above will be described next with reference to  FIGS. 4 and 5 .  FIG. 4  is a view showing the airbag  120  shown in  FIG. 3  seen from the front side of the vehicle when the airbag  120  is completely inflated.  FIG. 5  is a view showing the airbag  120  shown in  FIG. 3  seen from a side of the vehicle when the airbag  120  is completely inflated. In  FIG. 4 , the head of the passenger C is located at a position indicated by phantom line before a side collision or roll-over of the vehicle, and is located at a position indicated by a solid line when a side collision or roll-over of the vehicle occurs.  FIG. 4  is a view showing the right sidewall of the vehicle, and a right direction is a direction toward the inside of the vehicle and a left direction is a direction toward the outside of the vehicle. In  FIG. 5 , a left direction is the direction toward the front side of the vehicle and the right direction is the direction toward the rear side of the vehicle. 
         [0039]    When the vehicle undergoes a side collision or roll-over, the airbag apparatus  100  in the initial state is activated, and the first inflator  111  and the second inflator  112  generate the inflation gas. The gas generated from the first inflator  111  is supplied to the inner space of the front inflatable part  123  through the first inlet  121 . The gas generated from the second inflator  112  is supplied to the inner space of the rear inflatable part  124  through the second inlet  122 . The gas is steadily directed into the inner spaces of the front inflatable part  123  and the rear inflatable part  124  through the first inlet  121  and the second inlet  122 , respectively, to produce a predetermined flow of gas. Accordingly, the entire airbag  120  starts to be inflated (expands while deploying). As shown in  FIG. 4 , the airbag  120  pushes the ceiling panel  15  to open and is inflated downwardly into the passenger-protection regions P 1 , P 2 , and P 3  between the right sidewall (side window  10 ) and the passengers C. 
         [0040]    Accordingly, the airbag  120  is inflated as shown in  FIGS. 4 and 5 . The upper portion of the airbag  120  is supported on the right-side roof rail  19  with the plurality of brackets  125 , and is quickly and reliably inflated in the space between the right sidewall (side window  10 ) and the heads of the passengers C (passenger-protection regions P 1 , P 2 , and P 3  in  FIG. 4 ). At this time, among the inflatable parts of the airbag  120 , the first inflatable chamber  123   a  of the front inflatable part  123  is inflated in the passenger-protection region P 1  corresponding to the first seat-row S 1  for protecting at least the head of the passenger C seated in the first seat-row S 1 . Among the inflatable parts of the airbag  120 , the second inflatable chamber  123   b  of the front inflatable part  123  and the third inflatable chamber  124   a  of the rear inflatable part  124  is inflated while vertically overlapping each other in the passenger-protection region P 2  corresponding to the second seat-row S 2  (passenger-protection regions corresponding to a predetermined number of seat-rows) for protecting at least the head of the passenger C seated in the second seat-row S 2 . Among the inflatable parts of the airbag  120 , the fourth inflatable chamber  124   b  of the rear inflatable part  124  is inflated in the passenger-protection region P 3  corresponding to the third seat-row S 3  for protecting at least the head of the passenger C seated in the third seat-row S 3 . Accordingly, the airbag  120  has the inflatable part (section) inflated in at least the passenger-protection region P 3  corresponding to the third seat-row S 3 . 
         [0041]    As described above, the airbag apparatus  100  according to the present invention can be quickly and reliably inflated even when the airbag has a large size and volume suitable for a large vehicle capable of having at least a three-seat-row arrangement. More specifically, an airbag for a large vehicle capable of having a three-seat-row arrangement needs to have a large size and volume as opposed to an airbag for a small vehicle having a two-seat-row arrangement. Accordingly, the airbag for a large vehicle needs to have a special structure to be quickly and reliably inflated. 
         [0042]    In the embodiment, the inside of the airbag  120  of the airbag apparatus  100  is sectioned into the front inflatable part  123  and the rear inflatable part  124 . Furthermore, the inflators  111  and  112  are used to individually supply gas to each inflatable part. Accordingly, it is possible to quickly supply gas to each inflatable part even when the airbag  120  has a large size and volume. Moreover, it is possible to reliably supply gas to a plurality of inflatable parts as compared with distributing and supplying gas from one inflator to each inflatable part. 
         [0043]    In the embodiment, the airbag  120  of the airbag apparatus  100  has a simple structure in which one inflatable part (front inflatable part  123 ) is inflated across the two passenger-protection regions P 1  and P 2  and another inflatable part (rear inflatable part  124 ) is inflated across the two passenger-protection regions P 2  and P 3 . The inflated front inflatable part  123  and rear inflatable part  124  overlap each other in the passenger-protection region P 2  corresponding to the second seat-row S 2 , thereby reliably protecting the passenger C seated in the second seat-row S 2 . 
         [0044]    In the embodiment, the airbag  120  of the airbag apparatus  100  extends continuously in the upper portion of the sidewall of the vehicle from the A pillar  12  to the B pillar  14 , i.e. a region corresponding to the first seat-row S 1 , and to the D pillar  18  through the C pillar  16 , i.e. a region corresponding to the third seat-row S 3 . Accordingly, as compared with a case wherein an airbag does not extend continuously from the A pillar  12  to the B pillar  14 , and extend to the D pillar  18  through the C pillar  16 , it is possible to inflate the airbag  120  in the passenger-protection region without a delay in inflation timing. 
         [0045]    The present invention is not limited to the embodiment described above, and may include various modifications and variations. For example, the embodiment described above may be modified to other embodiments as follows. 
         [0046]    In the embodiment described above, the airbag apparatus  100  is provided on the right side of the vehicle for protecting the passengers C seated on the right side of the vehicle. Another airbag apparatus with a structure same as that of the airbag apparatus  100  may be provided on the left side of the vehicle for protecting passengers C seated on the left side of the vehicle. In this case, the airbag apparatus on the left side has a structure symmetrical to that of the airbag apparatus  100  and is fixed to a left side roof rail. 
         [0047]    According to the present invention, the inside of the vehicle airbag may be divided in various ways other than that of the airbag  120 . As other embodiments of the airbag apparatus  100 , airbag apparatuses  200 ,  300 , and  400  will be described in terms of an inner structure of the vehicle airbag with referring to  FIGS. 6 to 8 . In  FIGS. 6 to 8 , components same as those in  FIG. 3  are indicated by the same reference numerals, and detailed descriptions of the components are omitted. 
         [0048]    The airbag apparatus  200  shown in  FIG. 6  (corresponding to the airbag apparatus of the present invention) is installed in a vehicle capable of providing a three-seat-row arrangement. The airbag apparatus  200  mainly includes an airbag  220  (corresponding to the airbag of the present invention) having three inflatable parts  223 ,  224 , and  225  (corresponding to the sections of the present invention) independent from each other; a first inflator  211  (corresponding to the gas supplying device of the present invention) capable of individually supplying inflation gas to the inflatable part  223 ; a second inflator  212  (corresponding to the gas supplying device of the present invention) capable of independently supplying inflation gas to the inflatable part  224 ; and a third inflator  213  (corresponding to the gas supplying device of the present invention) capable of independently supplying inflation gas to the inflatable part  225 . In this embodiment, the inflatable part  223  is inflated in the passenger-protection region P 1 , the inflatable part  224  is inflated in the passenger-protection region P 2 , and the inflatable part  225  is inflated in the passenger-protection region P 3 . 
         [0049]    The structure of the airbag apparatus  200  wherein one inflatable part corresponds to one passenger-protection region may be applied to a vehicle capable of having more than four-seat-rows. 
         [0050]    The airbag apparatus  300  shown in  FIG. 7  (corresponding to the airbag apparatus of the present invention) is installed in a vehicle capable of having a three-seat-row arrangement. The airbag apparatus  300  mainly includes an airbag  320  (corresponding to the airbag of the present invention) having two inflatable parts  323  and  324  (corresponding to the sections of the present invention) independent from each other; a first inflator  311  (corresponding to the gas supplying device of the present invention) capable of independently supplying inflation gas to the inflatable part  323 ; and a second inflator  312  (corresponding to the gas supplying device of the present invention) capable of independently supplying inflation gas to the inflatable part  324 . The inflatable part  324  includes a first chamber  324   a  and a second chamber  324   b . In this embodiment, the inflatable part  323  is inflated in the passenger-protection region P 1 , the first chamber  324   a  of the inflatable part  324  is inflated in the passenger-protection region P 2 , and the second chamber  324   b  of the inflatable part  324  is inflated in the passenger-protection region P 3 . 
         [0051]    The structure may be modified as required so that the inflatable part  323  is inflated in the passenger-protection regions P 1  and P 2  and the inflatable part  324  is inflated in the passenger-protection region P 3 . 
         [0052]    The airbag apparatus  400  shown in  FIG. 8  (corresponding to the airbag apparatus of the present invention) is installed in a vehicle capable of having a four-seat-row arrangement. The airbag apparatus  400  mainly includes an airbag  420  (corresponding to the airbag of the present invention) having three inflatable parts  423 ,  424 , and  425  (corresponding to the sections of the present invention) independent from each other; a first inflator  411  (corresponding to the gas supplying device of the present invention) capable of individually supplying inflation gas to the inflatable part  423 ; a second inflator  412  (corresponding to the gas supplying device of the present invention) capable of independently supplying inflation gas to the inflatable part  424 ; and a third inflator  413  (corresponding to the gas supplying device of the present invention) capable of independently supplying inflation gas to the inflatable part  425 . The inflatable part  423  includes a first chamber  423   a  and a second chamber  423   b . The inflatable part  424  includes a first chamber  424   a  and a second chamber  424   b . The inflatable part  425  includes a first chamber  425   a  and a second chamber  425   b.    
         [0053]    In this embodiment, the first chamber  423   a  of the inflatable part  423  is inflated in the passenger-protection region P 1 . The second chamber  423   b  of the inflatable part  423  and the first chamber  424   a  of the inflatable part  424  are inflated in the passenger-protection region P 2 , so that both chambers vertically overlap each other. The second chamber  424   b  of the inflatable part  424  and the first chamber  425   a  of the inflatable part  425  are inflated in the passenger-protection region P 3 , so that both chambers vertically overlap each other. The second chamber  425   b  of the inflatable part  425  is inflated in the passenger-protection region P 4 . 
         [0054]    Similar to the airbag apparatus  100 , the airbag apparatuses  200 ,  300 , and  400  can quickly provide gas to each inflatable part even when the airbag has a large size. Moreover, gas is reliably supplied to each inflatable part. In particular, the airbag apparatuses  300  and  400  have simple structures in which one inflatable part is inflated across the two passenger-protection regions P 2  and P 3 . 
         [0055]    In the embodiments, one airbag  120  including two inflatable parts (front inflatable part  123  and rear inflatable part  124 ) is provided for protecting the passengers C seated in the first S 1  to third seat-rows S 3 . The airbag apparatus may include a plurality of airbags having a plurality of sections such as inflatable parts, wherein the sections protect the passengers C seated in the first seat-row S 1  to the third seat-row S 3 . 
         [0056]    In the embodiments, the first inflator  111  and the second inflator  112  are disposed apart from each other. The present invention may include two inflators disposed integrally depending on a positional relationship of each inflatable part and each inlet. When the two inflators are disposed integrally, two independent gas-generating mechanisms may be disposed inside a single housing. 
         [0057]    In the embodiments, the front inflatable part  123  and the rear inflatable part  124  partially overlap each other in the vertical direction when the airbag  120  is inflated. In the present invention, a plurality of inflatable parts may overlap in any direction. Moreover, in the present invention, the front inflatable part  123  and the rear inflatable part  124  may entirely overlap each other. 
         [0058]    In the embodiments, the airbag apparatus is installed in an automobile capable of having a three-seat-row arrangement. The present invention may be applied to an airbag apparatus installed in various vehicles, such as a train or a marine vessel, in addition to small and large automobiles capable of having more than three rows of seats (i.e., a four-seat-row arrangement, a five-seat-row arrangement, or more). 
         [0059]    The disclosure of Japanese Patent Application No. 2003-430650, filed on Dec. 25, 2003, is incorporated in the application. 
         [0060]    While the invention has been explained with reference to the specific embodiments of the invention, the explanation is illustrative and the invention is limited only by the appended claims.