Abstract:
An airbag apparatus includes an airbag having an interior divided into a plurality of chambers, and a gas generator for inflating the airbag so that gas is guided directly to each chamber from the gas generator. Further, a gas distributor having a plurality of gas outlets is attached to a gas outlet of the gas generator. The gas is supplied to the respective chambers through the gas outlets of the gas distributor.

Description:
BACKGROUND OF THE ART AND RELATED ART STATEMENT  
         [0001]    The present invention relates to an airbag apparatus for protecting an occupant in a vehicle or the like, and more specifically, it relates to an airbag apparatus including an airbag having an interior divided into a plurality of chambers.  
           [0002]    As well known, in an airbag apparatus, an airbag is inflated with a gas generator to receive an occupant&#39;s body with the inflated airbag.  
           [0003]    It has been known that some type of the airbags has an arrangement in which an interior of the airbag is divided into a plurality of chambers. In such an airbag, gas is supplied from a gas generator to one of the chambers to inflate that chamber first, then the gas passing through the one chamber flows into the other chambers to inflate the same, so that the one chamber where an occupant abuts first is inflated prior to the other chambers.  
           [0004]    An object of the present invention is to provide an airbag apparatus in which gas from a gas generator is directly supplied to each chamber of an airbag.  
           [0005]    Further objects and advantages of the invention will be apparent from the following description of the invention.  
         SUMMARY OF THE INVENTION  
         [0006]    In an airbag apparatus according to the present invention, an airbag apparatus includes an airbag having an interior divided into a plurality of chambers, and a gas generator for inflating the airbag so that gas is guided directly to each chamber from the comnon gas generator.  
           [0007]    In such an airbag apparatus, the gas from the gas generator is directly supplied to each chamber without passing through the other chamber. Accordingly, each chamber may be independent without communicating with each other, and a size of a gas inlet in each chamber may be adjusted depending on a desired gas pressure. Therefore, an amount and a pressure of the gas guided to each chamber can be separately adjusted so that the gas pressure of each chamber becomes the desired gas pressure.  
           [0008]    In the present invention, it is preferable that a gas distributor having a plurality of gas outlets is attached to a gas outlet of the gas generator. The gas is supplied to the respective chambers through the gas outlets of the gas distributor. With the gas distributor as described above, it is easy to obtain a proper amount and pressure of the gas distributed to each chamber. Also, the gas generator can be a commercially available product and only the gas distributor to be mounted thereto is separately designed, thereby reducing a cost.  
           [0009]    In this case, a size of the gas outlet of the gas distributor may be designed depending on inflation characteristics of each chamber, thereby making it easy to obtain the desired amount and pressure of the gas supplied to each chamber. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is a perspective view showing a vehicle seat having a side airbag apparatus according to an embodiment of the invention;  
         [0011]    FIGS.  2 ( a ) and  2 ( b ) are sectional views showing an airbag, wherein FIG. 2( a ) is a sectional view taken along line  2 ( a )- 2 ( a ) in FIG. 1, and FIG. 2( b ) is a sectional view taken along line  2 ( b )- 2 ( b ) in FIG. 2( a );  
         [0012]    [0012]FIG. 3 is a perspective view of a gas generator and a gas distributor; and  
         [0013]    [0013]FIG. 4 is a partially sectional perspective view of the gas generator and the gas distributor. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0014]    Hereunder, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view of a vehicle seat having a side airbag apparatus serving as an airbag apparatus according to an embodiment; FIG. 2( a ) is a sectional view taken along line  2 ( a )- 2 ( a ) in FIG. 1; FIG. 2( b ) is a sectional view taken along line  2 ( b )- 2 ( b ) in FIG. 2( a ); FIG. 3 is a perspective view of a gas generator and a gas distributor; and FIG. 4 is a partially sectional perspective view of the gas generator and the gas distributor.  
         [0015]    As shown in FIG. 1, a side airbag  1  is constructed so as to inflate along a window side portion of a seat  10 . The seat  10  includes a seat cushion  11 , a seat back  12 , and a headrest  13 .  
         [0016]    The seat back  12  has a casing (not shown) of the side airbag apparatus mounted on a side thereof. The folded side airbag  1  is housed in the casing and the casing is covered with a module cover (not shown).  
         [0017]    The side airbag  1  is formed of a sheet-like material such as cloth and a plastic sheet formed in a bag shape, wherein an interior is divided into a lower first chamber  1   a  and an upper second chamber  1   b  with a partition panel  2  extending substantially horizontally inside the bag. The first chamber  1   a  and the second chamber  1   b  are not substantially communicated with each other.  
         [0018]    In this embodiment, the side airbag  1  includes a gas generator  3  therein. A holder (not shown) supports the gas generator  3 , and the holder is fixed to the casing together with the side airbag  1 . In other words, a back surface of the side airbag  1  is interposed between the holder and the casing, and the back surface of the side airbag  1  is fastened to the casing with bolts or rivets, so that the back surface of the side airbag  1  is fixed to the casing together.  
         [0019]    The gas generator  3  is provided with a gas distributor  4 . In this embodiment, as shown in FIGS. 3 and 4, the gas generator  3  has a substantially cylindrical shape, one end of which is provided with gas jets or outlets  5 . The gas distributor  4  formed in a substantially hemispherical shell is fastened to the gas generator  3  so as to surround the gas outlets  5 . The gas distributor  4  is firmly fastened to the gas generator  3  by press fitting or welding.  
         [0020]    The gas distributor  4  includes two gas outlets  4   a  and  4   b.  The first gas outlet  4   a  is oriented in a direction substantially the same as a direction that a central axis of the cylindrical gas generator  3  extends toward the one end. The second gas outlet  4   b  is oriented in a direction substantially perpendicular to the central axis.  
         [0021]    The first gas outlet  4   a  has a diameter larger than that of the second gas outlet  4   b.  The first gas outlet  4   a  is inserted in the first chamber  1   a  and the second gas outlet  4   b  is inserted in the second chamber  1   b,  as shown in FIG. 2.  
         [0022]    In the side airbag apparatus with such a configuration, in an event of a side collision or an overturning of the vehicle, the gas generator  3  emits the gas. The gas is emitted from the gas outlets  5  and flows into the first chamber  1   a  and the second chamber  1   b  through the gas outlets  4   a  and  4   b  of the gas distributor  4 , respectively, to inflate the chambers  1   a  and  1   b.  Thus, the airbag  1  is deployed along the window side of the seat  10 , as shown in FIG. 1. In this case, the first gas outlet  4   a  has a diameter larger than that the second gas outlet  4   b.  Therefore, the gas is supplied to the first chamber  1   a  in a larger quantity at a higher pressure than that supplied to the second chamber  1   b.  Consequently, the first chamber  1   a  is inflated at a higher internal pressure to receive a waist of an occupant moving laterally. The second chamber  1   b  is inflated at an internal pressure lower than that of the first chamber  1   a,  which is preferable for softly receiving a right upper half of the occupant body.  
         [0023]    In this embodiment, the gas generator  3  can be one widely available, and the gas distributor  4  is fitted to the gas generator, so that a cost is low. Also, sizes of the gas outlets  4   a  and  4   b  of the gas distributor  4  can be designed depending on a desired internal pressure of the chambers  1   a  and  1   b.    
         [0024]    In the above embodiment, since the inside of the first chamber  1   a  becomes a high pressure, the sheet-like material for surrounding the first chamber  1   a  may be formed of a material with high air-tightness, i.e. no air permeability. Also, a joining section (for example, a seam) of the sheet-like material for forming the first chamber  1   a  may be formed air-tightly.  
         [0025]    In the embodiment, the side airbag  1  is divided into the two chambers. However, it may be divided into three or more chambers and the gas distributor  4  may include three or more gas outlets.  
         [0026]    The gas distributor  4  can be formed of metal, a synthetic resin, or ceramic. However, the gas distributor may be made of cloth in this invention.  
         [0027]    In the aforementioned embodiment, the gas generator is formed in a cylindrical shape. However, the gas generator may have various shapes, such as a disc. The present invention can be applied to various types of airbag apparatus other than the side airbag apparatus.  
         [0028]    As described above, according to the present invention, when the airbag with the divided chambers is inflated, the pressure can individually be adjusted.  
         [0029]    While the invention has been explained with reference to the specific embodiments, the explanation is illustrative and the invention is limited only by the appended claims.