Patent Publication Number: US-2007108745-A1

Title: Side impact airbag

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to side impact airbags for vehicles.  
      2. Background Art  
      Vehicle airbags are used to protect vehicle occupants in the event of a collision. Airbags were initially provided on the dashboard and steering wheel of vehicles to protect against front end collisions. More recently, side impact airbags have been developed to protect vehicle occupants in the event of a side impact. Side impact airbags are inflated by means of an inflator that inflates the airbag with a gaseous medium when an impact is detected by side impact sensors provided on the vehicle.  
      Some prior art side impact airbags when inflated extend from a mounting location on one side of a seat back forwardly between the vehicle door and the occupant to cover the entire side of an occupant&#39;s body. This type of side impact airbag, when deployed, extends across the coronal plane of an occupant&#39;s body. The coronal plane is a line extending between a person&#39;s hip and shoulder. Generally, the widest part of a person&#39;s body corresponds to the coronal plane.  
      A side impact airbag may be inflated to place a cushion between a vehicle body part that may intrude into the passenger cabin and a person&#39;s body in the event of an impact. Side impact airbags inflate very rapidly while the intruding structure of the vehicle body is moving toward the vehicle occupant.  
      One problem with such prior art side impact airbags is that the combined force of the intruding structure and the force of the side impact airbag inflation may actually not reduce the lateral forces applied to an occupant&#39;s body. There is a need for an effective side impact airbag that effectively reduces the load that an occupant will experience.  
      An additional problem is that the greater the volume of the airbag, the more time is required to deploy the airbag. Larger volume airbags also require larger inflators. Increasing the size of a side impact airbag and its associated inflator also increases the cost of the side impact airbag system. There is a need for a side impact airbag that reduces the time required for full deployment and reduces system cost.  
      One test developed for side impact airbags is the IIHS high hooded barrier side impact test. It is desirable to develop side impact airbags that meet this IIHS test without degrading test performance according to other test procedures. There is a need to develop side impact airbags that meet all of the requirements of any and all such tests.  
      There is a need to provide a side impact airbag having a shape that is optimized to manage intruding energy, but not overload the occupant. There is also a need to provide a side impact airbag that loads bio-mechanically appropriate areas of the body to start moving the occupant away from the intrusion sooner than prior art side impact airbags.  
      Applicants&#39; invention is directed to solving the above problems and fulfilling the above needs as summarized below.  
     SUMMARY OF THE INVENTION  
      According to one aspect of the present invention, a side impact airbag system is provided for a vehicle having a seat. The seat includes a seat back that has an attachment structure and deployment opening. The system comprises an inflator and an airbag that is attached to the seat back of the vehicle seat. The airbag has a primary inflation chamber that extends from the attachment structure in the forward direction to a limited extent. The primary inflation chamber extends forwardly to a point that is rearward of a coronal plane that is defined as a line extending from a shoulder to a hip of the vehicle occupant.  
      According to other aspects of the invention, a supplemental inflation chamber may be provided that is disposed forward of the primary inflation chamber. The supplemental inflation chamber is inflated by the inflator along with the primary inflation chamber. The primary inflation chamber, when inflated, has a lateral width that is greater than the supplemental inflation chamber. For example, the supplemental inflation chamber may be less than half of the lateral width of the primary inflation chamber.  
      According to other aspects of the invention as it relates to a side impact airbag system, the primary inflation chamber may engage the occupant at a location rearward of the coronal plane to apply a force to the occupant causing the occupant to move away from the side of the vehicle adjacent the seat. A primary inflation chamber may be cylindrical when inflated or may be oblong or irregularly shaped. The inflator may be attached to the airbag and an attachment structure on the seat back.  
      According to another aspect of the present invention, a passive restraint vehicle occupant protection system is provided. The vehicle body may have an impact protection area and a sensing system for sensing an impact to the impact protection area. An inflator is provided that may be selectively activated by the sensing system in response to the sensing system sensing an impact. The airbag is inflated by the inflator and is disposed to move an occupant away from the impact protection area. The airbag, when inflated, is disposed generally between the impact protection area and the occupant&#39;s body, and extends from the seat back and only up to the coronal plane of the occupant&#39;s body.  
      According to other aspects of the invention as they relate to the airbag system, the impact protection area is a side of the vehicle and the airbag is a side impact airbag. The coronal plane of an occupant&#39;s body extends through the occupant&#39;s hip and shoulder. The airbag, when inflated, is spaced rearwardly from the coronal plane.  
      According to other aspects of the invention, a foreign body impacting the vehicle in the impact protection area may cause a portion of the vehicle body to intrude into the vehicle interior toward the occupant. The airbag is positioned so that it inflates and has a maximum width that is located behind the coronal plane.  
      These and other aspects of the invention will be better understood and readily apparent in view of the attached drawings and the following detailed description of the illustrated embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a diagrammatic side elevation view of a person in a vehicle seat having a side impact airbag made in accordance with one embodiment of the present invention;  
       FIG. 2   a  is a cross-sectional view of the side impact airbag of the present invention with an interrupted seam to divide the airbag into a primary and a secondary inflation chamber that is taken along the line  2   a - 2   a  in  FIG. 1  and is shown in conjunction with a diagrammatic view of a seated person;  
       FIG. 2   b  is a cross-sectional view similar to the section of  FIG. 2   a  but showing a tether that is used to divide the airbag into a primary and a secondary inflation chamber;  
       FIG. 3  is a diagrammatic side elevation view of an alternative embodiment of a side impact airbag and a person seated in a vehicle seat;  
       FIG. 4  is a cross-sectional view taken the line  4 - 4  in  FIG. 3 ; and  
       FIG. 5  is a cross-sectional view taken along the line  5 - 5  in  FIG. 3 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)  
      Referring to  FIGS. 1 and 2 , an airbag  10  is shown in its deployed condition in conjunction with a vehicle seat  12 . Vehicle seat  12  has a seat back  14  in which the airbag  10  is stored until it is ready to be deployed.  
      An occupant  16  is shown seated in the vehicle seat  12 . A shoulder  18  and hip  20  of the occupant  16  are indicated with an axis line representative of a coronal plane  22  being illustrated that extends through the shoulder  18  and the hip  20  of the occupant  16 . The coronal plane  22  is a planar section taken through a person&#39;s body at the shoulder  18  and hip  20 , or h-point, that generally corresponds to the widest portions of the occupant&#39;s body.  
      An inflator  24  may be provided at any height on the seat back  14 . The inflator  24  rapidly expels a gaseous medium into the airbag  10  in the event of a side impact. A side impact may be detected by sensors  26  that are disposed on the vehicle body at various locations. The sensors  26  provide a signal to a controller  28  in the event of a side impact. The controller  28  signals the inflator  24  to deploy the airbag  10 .  
      The airbag  10  has a primary inflation chamber  30  that, when inflated, expands to a point rearward of the coronal plane  22 . Upon inflation, the primary inflation chamber  30  engages the occupant  16  generally behind the occupant&#39;s shoulder  18  and hip  20  causing the occupant  16  to move inwardly toward the center of the vehicle and away from the side of the vehicle that is subject to the side impact. The airbag  10  can be made in a range of sizes to cover an occupant&#39;s shoulder, thorax, abdomen and pelvis. Alternatively, any one of the listed anatomical regions may be covered or combinations of adjacent regions may be covered by the airbag  10 .  
      A secondary inflation chamber  32  may be provided, if desired, to provide a reduced width cushion between the occupant&#39;s body  16  that extends across the coronal plane  22 . The secondary inflation chamber  32  may be separated from the primary inflation chamber  30  at  36  by either an interrupted seam or a tethered area. If an interrupted seam is provided at  36 , as shown in  FIG. 2   a , a plurality of air passages  38  are provided through which the gaseous medium emitted by the inflator  24  flows to inflate the secondary inflation chamber  32  in conjunction with the inflation of the primary inflation chamber  30 . Alternatively, if a tethered area is provided at  36 , as shown in  FIG. 2   b , gas flow is provided to the secondary inflation chamber through less restricted air passages  38 .  
      Referring to  FIGS. 3 through 5 , an alternative embodiment of an airbag  40  is illustrated in its deployed condition. The airbag  40  is shown in conjunction with diagrammatic representation of an occupant  42  seated in a vehicle seat  44 . The airbag  40  is deployed in a manner similar to the deployment of airbag  10  described above. For brevity, the description of the deployment process is not repeated for the embodiment of airbag  40 .  
      A supplemental shoulder extension  46  and supplemental hip extension  48  are provided forward of the airbag  40 . The illustrated extensions  46 ,  48  are relatively short, but could be substantially longer, if desired. The supplemental shoulder extension  46  and supplemental hip extension  48  are separated from the airbag  40  by interrupted seams  50 . The supplemental shoulder and hip extensions  46  and  48 , while differently shaped, function in a manner similar to the secondary inflation chamber  32  of the embodiment of  FIGS. 1 and 2 . The interrupted seams  50  allow the gaseous medium to flow from airbag  40  into the shoulder and hip extensions  46  and  48 .  
      The supplemental shoulder and hip extensions  46  and  48  is less than the width of the airbag  40 . When the airbag  40  is inflated, it engages the body of an occupant behind the coronal plane  22  to urge the occupant&#39;s body toward the center of the vehicle and away from the side impact location. The supplemental shoulder and hip extensions  46  and  48  provide a buffer adjacent an occupant&#39;s shoulder and hip.  
      A tether  52  may be provided to divide the airbag  40  into differently pressurized zones. The tether  52  may be oriented at different angles depending upon vehicle design considerations.  
      While the best mode for carrying out the invention has been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims.