Patent Publication Number: US-2006012155-A1

Title: Vehicle side airbag apparatus and seat containing same

Description:
BACKGROUND OF INVENTION  
      1. Field of the Invention  
      The present invention relates to a vehicle side airbag apparatus and a seat containing such an airbag apparatus.  
      2. Background Art  
      Many vehicles today contain side airbags, the purpose of which is to protect a vehicle occupant when the vehicle is involved in a side impact collision. These side airbags may be mounted to a vehicle seat, or may be located under a portion of the interior trim. Side airbags typically attempt to provide some thorax/abdominal coverage for the vehicle occupant, and may also be configured to protect an occupant&#39;s head area. Alternatively, the side airbag may work in conjunction with an air curtain, which may deploy downward from the vehicle headliner.  
      In order to reduce the loading on the thorax—i.e., the upper body, including the ribs—some side airbags are inflated or vented to a lower pressure than may otherwise be desirable. For example, an occupant&#39;s shoulder and pelvic area can typically sustain higher loading than the thorax region, and therefore, may benefit by an airbag having a higher pressure. One way to address this situation is to provide a side airbag which is configured to contact the upper regions of an occupant&#39;s body, and to also provide a separate, pelvic airbag, configured to contact the lower regions of the occupant&#39;s body. Another attempt to deal with this issue is described in U.S. patent application Publication No. 2003/0168836 filed by Sato et al., and published on Sep. 11, 2003. Sato et al. describes an airbag apparatus having upper and lower portions, and an intermediate portion therebetween. The intermediate portion is located to correspond with the thorax of a seated occupant. The airbag apparatus of Sato et al. includes a limiting mechanism that limits the bulging of the intermediate portion such that the thickness of the intermediate portion is less than the thickness of the upper and lower portions. The airbag apparatus of Sato et al. is thus configured to contact an occupant&#39;s shoulder and pelvic region, while maintaining a space between the deployed airbag and the occupant&#39;s thorax. One limitation of the Sato et al. airbag apparatus, is that it requires multiple chambers in the airbag, which significantly increases the complexity of the airbag apparatus. Moreover, the limiting mechanism used by Sato et al. to limit the bulging of the intermediate portion further adds complexity to the airbag apparatus, which may increase both labor and material costs.  
      Therefore, a need exists for a vehicle side airbag apparatus that inhibits loading on the thorax of a vehicle occupant, and also keeps down production costs.  
     SUMMARY OF INVENTION  
      Accordingly, the present invention provides a vehicle side airbag apparatus and a vehicle seat including a side airbag apparatus, wherein thorax loading on a seated occupant is inhibited and manufacturing costs are kept down.  
      The invention also provides a side airbag apparatus for a vehicle, including an airbag having a generally wedge shaped rear aspect when deployed. The generally wedge shaped rear aspect narrows from an upper region to a lower region, thereby inhibiting loading on the thorax of an occupant of the vehicle seated adjacent the deployed airbag. The airbag apparatus also includes an inflator cooperating with the airbag to supply gas thereto, thereby facilitating deployment of the airbag.  
      The invention further provides an airbag apparatus for a vehicle, including an airbag having a generally wedge shaped rear aspect when deployed. The generally wedge shaped rear aspect narrows from an upper region to a lower region, thereby inhibiting loading on the thorax of an occupant of the vehicle seated adjacent the deployed airbag. The airbag also has a side aspect including first and second portions. The first portion is generally triangular, and narrows from a back region to a front region, thereby further inhibiting loading on the thorax of an occupant of the vehicle seated adjacent the deployed airbag. The second portion is contiguous with the first portion and includes at least one mounting hole. An inflator is configured for attachment to the airbag at the at least one mounting hole, and cooperates with the airbag to supply gas thereto. This facilitates deployment of the airbag.  
      The invention also provides a vehicle seat including a side airbag apparatus. The airbag apparatus includes an airbag having a generally wedge shaped rear aspect when deployed. The generally wedge shaped rear aspect narrows from an upper region to a lower region, thereby inhibiting loading on the thorax of an occupant of the vehicle seated adjacent the deployed airbag. An inflator is mounted on a portion of the seat, and cooperates with the airbag to supply gas thereto, thereby facilitating deployment of the airbag. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       FIG. 1  shows a side view of a vehicle seat and airbag apparatus in accordance with the present invention;  
       FIG. 2  shows a side plan view of the airbag shown in  FIG. 1 ;  
       FIG. 3  shows a rear plan view of the airbag and inflator shown in  FIG. 1 ;  
       FIG. 4  shows a top plan view of the airbag and inflator; and  
       FIG. 5  shows a top plan view of the vehicle seat and airbag apparatus shown in  FIG. 1 , relative to a portion of a vehicle door panel. 
    
    
     DETAILED DESCRIPTION  
       FIG. 1  shows a vehicle seat  10  including an airbag apparatus  12  in accordance with the present invention. The airbag apparatus  12  includes an airbag  14  and an inflator  16 , which cooperates with the airbag  14  to supply gas to the airbag  14 , thereby facilitating deployment of the airbag  14 . In the embodiment shown in  FIGS. 1 and 2 , the airbag  14  has a generally wedge shaped side aspect when deployed. The generally wedge shaped side aspect includes a posterior edge  18 , a top edge  20  which extends forward from the posterior edge  18 , and a bottom edge  22 , a portion of which extends forward and upward from the posterior edge  18 .  
      The wedge shaped side aspect of the airbag  14  helps to inhibit loading on the thorax of an occupant  24  seated adjacent the deployed airbag  14 . As explained below, in conjunction with  FIG. 3 , the airbag  14  also has a generally wedge shaped rear aspect. Having a rear aspect that is wedge shaped allows the side aspect to be non-wedge shaped—e.g., rectangular, round, etc.—while still inhibiting loading on the thorax of the vehicle occupant.  
       FIG. 2  shows a side view of the airbag  14  prior to installation into the vehicle seat  10 . As shown in  FIG. 2 , the airbag  14  may be generally divided into first and second portions  26 ,  28 . For convenience, an axis  30  is shown to represent a line of demarcation between the two airbag portions  26 ,  28 . It is worth noting that the first and second portions  26 ,  28  merely divide the airbag  14  according to the geometry of its side aspect. Although an airbag, such as the airbag  14 , may be divided internally into one or more chambers, the first and second portions  26 ,  28  of the airbag  14  denote a convenient means for describing the shape of the airbag  14 , which is configured to inhibit loading on the thorax of a vehicle occupant.  
      As shown in  FIG. 2 , the first portion  26  of the airbag  14  is generally triangular, and narrows from a back region  29 , adjacent the axis  30 , to a front region  31 , adjacent the front  33  of the airbag  14 . It is clear that the first portion  26  is not precisely a triangle, but rather, includes a rounded corner  32 . The rounded corner  32  helps to eliminate stress concentrations that could occur in an airbag having a sharp corner. This provides another benefit, because, as explained below, it allows the airbag  14  to be inflated to a higher pressure than typical side airbags.  
      The generally triangular shape of the first portion  26  provides a loading on the shoulder and upper arm of a vehicle occupant, such as the vehicle occupant  24  shown in  FIG. 1 . At the same time, because a portion of the bottom edge  22  extends forward and upward, the airbag  14  will have little or no contact with the lower arm of a vehicle occupant, or the occupant&#39;s ribs. Without such a configuration, a side airbag may directly impact the thorax of a vehicle occupant, or alternatively, may impact an occupant&#39;s lower arm, thereby driving the lower arm into the thorax region. In contrast, the airbag  14  eliminates that portion of an airbag that would cause a high degree of rib loading on a vehicle occupant.  
      The second portion  28  of the airbag  14  is contiguous with the first portion  26 , and includes a number of mounting holes  34 . The mounting holes  34  are provided to attach the inflator  16  to the airbag  14 . This can be done in any convenient manner, for example, by using an inflator having threaded studs extending outward that can traverse the holes  34 , and allow the inflator to be attached to a seat, such as the seat  10 . Although the mounting holes  34  go through the airbag  14 , they are isolated from that portion of the airbag  14  that is filled with gas by the inflator  16 . As shown in  FIG. 2 , the airbag  14  also includes reinforced regions  35 ,  37 , around the mounting holes  34  for providing additional strength to the airbag  14 . In the regions  35 ,  37 , additional pieces of material are sewn into the airbag  14  to help ensure that the airbag  14  will maintain its integrity if it is inflated to a relatively high pressure, even at elevated temperatures.  
      An optional vent hole  36  is provided in one side of the airbag  14  to facilitate venting of the gas from the airbag  14 . Because the gas may be vented at a high pressure, a vent hole, such as the vent hole  36 , will typically be located on the side of the airbag away from the occupant—i.e., the side facing the vehicle door. Although the vent hole  36  need not be of any particular size, a vent hole having a radius of up to 25 millimeters (mm) has been found to be effective to vent gas from the airbag, and at the same time reduce the stress concentrations associated with a structural discontinuity, such as a hole.  
      The shape of the airbag  14  also provides advantages for packaging the airbag apparatus  12  within a vehicle seat, such as the seat  10 . For example, the front portion of the airbag  14 , defined in part by the rounded corner  32 , can be rolled backward until it reaches an inflator, such as the inflator  16 , mounted at the mounting holes  34 . Thus, the airbag  14  does not require an elaborate scheme of folding portions into a complex geometrical configuration in order to ensure proper deployment. Rather, the generally triangular shape of the first portion  26  allows the airbag  14  to be quickly rolled into a packaged configuration. This saves labor costs and reduces assembly time.  
      In addition, because the first portion  26  has a generally triangular shape and narrows from the back region  29  to the front region  31 , it is generally easier to deploy through a tear seam in a cover material, such as the upholstery  38  on the seat  10 . In particular, because the smaller, front region  31  of the airbag  14  contacts the tear seam in the cover material, there is a higher stress on the tear seam than if the front region  31  of the airbag  14  were as large as the back region  29 . Another benefit of the generally triangular shaped first portion is that the airbag  14  requires less material than airbags having, for example, rectangular side aspects. This results in lower airbag costs, and reduced package space, thereby allowing the airbag  14  to be used in a wide variety of vehicle seats and vehicle platforms.  
      In addition to inhibiting thorax loading because of its generally wedge shaped side aspect, the airbag  14  also inhibits loading on an occupant&#39;s thorax by having a generally wedge shaped rear aspect.  FIG. 3  shows the rear aspect of the airbag apparatus  12 , including the airbag  14  and the inflator  16 . As shown in  FIG. 3 , the airbag  14  has a generally wedge shaped rear aspect that narrows from an upper region  39 , adjacent the top  41  of the airbag  14 , to a lower region  43 , adjacent the bottom  45  of the airbag  14 . This provides the maximum contact with a vehicle occupant near the top  41  of the airbag  14 , which coincides with the shoulder of the vehicle occupant. Because the shoulder can absorb relatively high loading, this design provides a maximum loading where the vehicle occupant is best suited to receive it. In addition, because the lower portion of the rear aspect is narrowed, less of the airbag  14  contacts the thorax of the vehicle occupant, and it is less likely to contact the lower portion of the occupant&#39;s arm, thereby driving the arm into the thorax.  
      The airbag  14  also has a generally wedge shaped top aspect, as shown in  FIG. 4 . The generally wedge shaped top aspect narrows from a posterior region  47 , adjacent the rear  49  of the deployed airbag  14 , to the front region  31 . This also helps to provide a maximum loading at an occupant&#39;s shoulder, where the occupant is best able to receive it. In addition, because the airbag  14  has a generally wedge shaped top aspect, it is much more easily adapted to smaller vehicles than are non-wedge shaped airbags. For example,  FIG. 5  shows a top view of the vehicle seat  10 , the airbag apparatus  12  with the airbag  14  deployed, and a portion of a vehicle door panel  40 . Although larger vehicles, such as sport utility vehicles (SUV&#39;s) may provide ample room between a vehicle seat and the vehicle door trim panel or B-pillar trim, smaller vehicles are often much more tightly packaged.  
      The reduced space between the vehicle seat and the aforementioned trim components requires special considerations for side airbags. For example, it may be undesirable to have a side airbag impact the vehicle door trim panel or B-pillar trim as it deploys. Therefore, in certain vehicle architectures, where the space between the vehicle seat and the vehicle door trim panel or B-pillar trim is relatively constrained, it may be necessary to orient the airbag with a smaller forward angle.  
       FIG. 5  shows that the vehicle seat  10  includes a longitudinal seat axis  42 . Moreover, the deployed airbag  14  defines an airbag axis  44 . In larger vehicles, it may be possible to mount an airbag apparatus such that the airbag axis forms an angle with the longitudinal seat axis that is 30° or greater. This keeps the deployed airbag angled away from the seated occupant, and because of the large space between the vehicle seat and the door panel, there is little or no chance that the airbag will rebound off the door panel to impact the occupant. In smaller vehicles, however, where it is necessary to reduce the angle between the airbag axis and the longitudinal seat axis, an airbag having a non-wedge shaped top aspect may deploy too closely to the seated occupant. In contrast, the airbag  14  of the present invention includes a generally wedge shaped top aspect, which allows the airbag apparatus  12  to be mounted to a portion of the seat  10  such that the airbag axis forms an angle with the longitudinal seat axis that is less than 30°. In particular, as shown in  FIG. 5 , the airbag axis  44  forms an angle with the longitudinal seat axis  42  that is approximately 22°. Because of the wedge shaped top aspect, the airbag  14  will not contact the door panel  40 , nor will it be deployed too closely to an occupant seated in the seat  10 .  
      As shown in  FIG. 1 , the generally wedge shaped side aspect of the airbag  14  helps to ensure that maximum loading is applied to the vehicle occupant, where the occupant is best suited to receive it. Although the generally wedge shaped side aspect of the airbag  14  may be configured with any dimensions effective to reduce loading on the thorax of the seated occupant, one such configuration is shown in  FIG. 1 . In particular, the seated occupant  24  may be a fifth percentile female side impact anthropometric test dummy (ATD), as used in vehicle safety testing.  
      The airbag  14 , shown in  FIG. 1 , is configured such that the bottom edge  22  projects up and forward at such an angle, that at least ¼ of the length (L) of the dummy&#39;s arm  46  is outside the airbag  14 , when the arm  46  is oriented at a 45° angle with respect to the neutral (down) position, as frequently used in vehicle safety testing. It is worth noting that the test dummy  24  has only an upper arm—i.e., an arm extending from shoulder to elbow; therefore, the length (L) is the length of only the upper arm. Such a configuration for an airbag has been shown to be effective to minimize the loading on the thorax of such a test dummy, both from direct contact by an airbag, as well as from the dummy&#39;s arm being forced into the thorax region by the airbag.  
      Because the present invention provides an airbag apparatus that minimizes loading on the thorax of the seated occupant, the pressure used to inflate the airbag can be greater than is typically used with side airbags. For example, many side airbags are inflated to only 10-15 pounds per square inch (psi). In contrast, the inflator  16  is configured to inflate the airbag  14  with a pressure that is at least 25 psi; of course, the pressure may be less if desired. Because the airbag  14  can be inflated to higher pressures than typical side airbags, it may be desirable to use a stronger material for the airbag  14 , than is used for typical side airbags. For example, many side airbags are made from a 420 denier polymeric material, or the like. Such material may not perform well when exposed to the temperatures associated with an airbag that inflates to 25 psi in 20-60 milliseconds (ms). One material shown to be effective for use in an airbag, such as the airbag  14 , is a 620 denier polymeric material.  
      In addition to using a stronger material, such as the 620 denier polymeric material, the airbag  14 , as discussed above, also includes reinforced regions  35 ,  37 —see  FIG. 2 . Also shown in  FIG. 2  is a third reinforced region  51 . The reinforced region  51  includes two additional layers of material sewn into the airbag  14  along the top edge  20 . In addition, extra stitching (not shown) can be used to further reinforce this edge. The reinforced region  51  is oriented along a length of the airbag  14  in the direction of deployment. This helps to provide additional strength to the airbag  14  in a direction of high magnitude forces during deployment. Moreover, the airbag  14  may experience elevated temperatures, particularly in hot weather climates; the reinforced region  51  helps to compensate for any loss of material strength resulting from elevated temperatures. Thus, the present invention provides yet another advantage over typical side airbags: it safely allows the airbag to be inflated to a higher pressure to provide increased protection, while at the same time reducing the loading on the thorax of the seated occupant.  
      While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.