Patent Publication Number: US-6988743-B2

Title: Airbag apparatus

Description:
BACKGROUND 
   The present invention relates to an airbag apparatus which is suitably used as a passenger- or driver-side airbag apparatus installed in front of an occupant in a vehicle such as an automobile. 
   A passenger-side airbag apparatus comprises a container arranged in an instrument panel in front of a front passenger seat, a gas generator for inflating an airbag, the airbag which is folded and accommodated in the container, and a lid covering the container. As a vehicle comes in collision, the gas generator is actuated to supply gas into the airbag, whereby the airbag starts to inflate. As the airbag starts to inflate, the lid is pushed by the airbag to open so that the airbag inflates toward the vehicle cabin. The airbag is provided with a gas inlet for receiving gas from the gas generator. The peripheral edge of the gas inlet is connected to the container. 
   As described in Japanese Patent Unexamined Publication H04-100754 (incorporated by reference herein), the airbag is folded by a step of first reverse folding both left and right sides of the airbag toward the center, the airbag in this state being called as an interim folded body having a reduced lateral width, and a step of folding the interim folded body into a bellow, the airbag in this state being called as a lump body. Then, the lump body is accommodated in the container. 
   Hereinafter, the way of folding an airbag disclosed in the publication H04-100754 will be described with reference to  FIGS. 11 through 17 . 
     FIG. 11  is a perspective view showing an airbag  1  spread in a plane and a sub container  2 . The airbag  1  is an envelop-like object of which the shorter sides  1   b  are rectilinear and the right and left longer sides  1   a  are curved in arc-like shape. Formed in the center of a layer on a side opposite to the surface to be arranged to confront an occupant is gas inlet  3  for receiving gas from an inflator. Also formed in the layer are gas outlets (vent holes)  4  for buffering impact on the occupant when the occupant collides with the deployed (fully inflated) airbag. Numeral  5  designates rivet holes. The sub container  2  has a bottom face with holes  6  for passage of gas from the inflator. 
   As shown in  FIG. 12 , the airbag  1  is spread in a plane in a state that the sub container  2  is connected to the airbag  1 . Then, as shown in  FIG. 13  and  FIG. 14  (sectional view taken along a line XIV—XIV of  FIG. 13 ), portions along the longer sides  1   a  are folded inside the airbag  1  to make the width of the airbag  1  slightly smaller than the width of the sub container  2 , so as to form an interim folded body. 
   Next, as shown in  FIG. 15  (side view taken from a line XV—XV of  FIG. 13 ), the interim folded body is repeatedly folded into a bellow to make valley and mountain folds  7  in directions perpendicular to the rectilinear longer sides  1   a ′ of the interim folded body. As shown in  FIG. 16 , repeatedly folded portions are piled on each other to form a lump body and the lump body is accommodated in the sub container  2  ( FIG. 17 ). 
   In this publication H04-100754, the folded airbag is accommodated in the sub container  2  and the sub container  2  with the airbag is accommodated in a main container (not shown). However, the sub container may be omitted and in this case, the folded airbag is directly accommodated in a container. 
   In the conventional passenger-side airbag device, the airbag  1  is folded so as to form the lump body. The peripheral edge of the gas inlet  3  of the airbag  1  is connected to the sub container  2 . Assuming the area of the airbag  1  about the periphery of the gas inlet  3  is composed of two area: a windshield-side area  1 A connected to a windshield side  2 A of the sub container  2  and an occupant-side area  1 B connected to the occupant-side  2 B of the sub container  2 , the windshield-side area  1 A and the occupant-side area  1 B are equal in length. 
   Therefore, when the airbag  1  is inflated (deployed) by gas from the inflator, the airbag  1  is deployed such that a vehicle-front side portion i.e. the windshield side portion and a vehicle-rear side portion i.e. the occupant side portion of the airbag are substantially symmetrically inflated. 
   It was found from various studies that the smooth deployment of the airbag may be obtained by such a structure that the front portion (vehicle-front side portion) of the airbag is inflated earlier than the rear portion (vehicle-rear side portion) of the airbag, but of course, it depends on the layout of the cabin and the arrangement angle of the instrument panel of the vehicle and the arrangement of the airbag apparatus. 
   It is an object of the present invention to provide an airbag apparatus in which a front portion (vehicle-front side portion) of an airbag is inflated earlier than a rear portion (vehicle-rear side portion) of the airbag. 
   SUMMARY OF THE INVENTION 
   According to an embodiment of the present invention an airbag apparatus comprising a folded airbag and a gas generator for inflating the airbag is provided. The airbag is configured to be deployed in front of an occupant, and the airbag may be folded so that a front portion thereof in the longitudinal direction of a vehicle is inflated earlier than a rear portion thereof. 
   According to an embodiment of the present invention, the rear portion of the airbag is first folded, then left and right portions are then folded, and after that, the front portion is folded, thereby ensuring that the front portion is inflated earlier than the rear portion in a process of deployment of the airbag. 
   It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features, aspects and advantages of the present invention will become apparent from the following description, appended claims, and the accompanying exemplary embodiments shown in the drawings, which are briefly described below. 
       FIG. 1(   a ) is a perspective view of a spread out airbag according to an embodiment of the present invention. 
       FIG. 1(   b ) is a sectional view taken along line Ib—Ib of  FIG. 1(   a ). 
       FIG. 2(   a ) is a perspective view of the airbag of  FIG. 1(   a ) with a rear portion of the airbag folded over a front portion of the airbag. 
       FIG. 2(   b ) is a sectional view taken along line IIb—IIb of  FIG. 2(   a ). 
       FIG. 3(   a ) is a perspective view of the airbag of  FIG. 2(   a ) with the rear portion of the airbag folded along fold lines extending in left and right directions. 
       FIG. 3(   b ) is a sectional view taken along line IIIb—IIIb of  FIG. 3(   a ). 
       FIG. 4(   a ) is a perspective view of the airbag of  FIG. 3(   a ) with the rear portion of the airbag folded in the opposite direction of  FIG. 2(   a ). 
       FIG. 4(   b ) is a sectional view taken along line IVb—IVb of  FIG. 4(   a ). 
       FIG. 5  is a perspective view of the airbag of  FIG. 4(   a ) with the left portion of the airbag fold over. 
       FIG. 6  is a perspective view of the airbag of  FIG. 5  with the left portion of the airbag folded into a narrow width. 
       FIG. 7  is a perspective view of the airbag of  FIG. 6  with the right portion of the airbag folded in a similar manner to the left portion. 
       FIG. 8  is a perspective view of the airbag of  FIG. 7  with the front portion of the airbag folded over and folded along fold lines extending in the left and right directions. 
       FIG. 9  is a sectional view of the folded airbag of  FIG. 8 . 
       FIGS. 10(   a )– 10 ( c ) depict the inflation sequence for the airbag apparatus according to the embodiment shown in  FIGS. 1–8 . 
       FIG. 11  is a perspective view of a conventional example. 
       FIG. 12  is a plane view of the conventional example. 
       FIG. 13  is an illustration for explaining the process of folding an airbag of the conventional example. 
       FIG. 14  is a sectional view taken along a line XIV—XIV of  FIG. 13 . 
       FIG. 15  is an illustration for explaining the process of folding the airbag of the conventional example. 
       FIG. 16  is an illustration for explaining the process of folding the airbag of the conventional example. 
       FIG. 17  is an illustration for explaining the process of folding the airbag of the conventional example. 
   

   DETAILED DESCRIPTION 
   Hereinafter, an embodiment of the present invention will be described with reference to the attached drawings.  FIG. 1(   a ) through  FIG. 9  are illustrations for explaining a process of folding an airbag of a passenger-side airbag apparatus according to the embodiment.  FIGS. 1(   a ),  2 ( a ),  3 ( a ),  4 ( a ) and  FIGS. 5–8  are perspective views,  FIGS. 1(   b ),  2 ( b ),  3 ( b ),  4 ( b ) are sectional views taken along line Ib—Ib, IIb—IIb, IIIb—IIIb, IVb—IVb of  FIGS. 1(   a ),  2 ( a ),  3 ( a ),  4 ( a ), respectively, and  FIG. 9  is a sectional view showing a state that the folded airbag is about to be assembled into a container.  FIGS. 10(   a )– 10 ( c ) are drawings for explaining profiles of the inflating airbag. 
   The passenger-side airbag apparatus  10  comprises an airbag  11 , a container  12  accommodating the airbag  11 , an inflator  13  which is attached to the container  12  for generating gas for inflating the airbag  11 , and a lid (not shown) for covering an opening in the top of the container  12 . As shown in  FIG. 9 , the airbag  11  is secured around its gas inlet to the container  12  by a fastening member  14 . 
   For folding and accommodating the airbag  11  into the container  12 , the airbag  11  is first spread in plain as shown in  FIGS. 1(   a ),  1 ( b ) and is folded in such a manner that a rear portion  11 A, to be arranged at the vehicle-rear side (at the instrument panel  20  side in  FIG. 10) , is superposed on the top of the container  12 . After that, as shown in  FIGS. 3(   a ),  3 ( b ), the rear portion  11 A is folded zigzag (i.e. in an accordion type fold) into a block shape which is long and narrow in the left-to-right direction. The folds formed by this folding extend in the left-to-right direction of the airbag  11 . 
   The rear portion  11 A in the block shape is reversed according to an arrow in  FIG. 3(   b ) and is sunk inside the airbag  11  as shown in  FIGS. 4(   a ),  4 ( b ). 
   After that, as shown in  FIG. 5 , a left portion  11 L of the airbag  11  is folded toward the right side in such a manner that the left portion  11 L is superposed on the top of the container  12  and, as shown in  FIG. 6 , is further folded several times into a narrow width. The folds formed by this folding of the left portion  11 L extend in the front-to-back direction. 
   Then, in a symmetrical manner as the left portion  11 L, a right portion  11 R of the airbag  11  is folded such that the right portion  11 R is superposed on the top of the container  12  and is further folded several times into a narrow width as shown in  FIG. 7 . The folds formed by this folding of the right portion  11 R extend in the front-to-back direction. 
   After that, as shown in  FIG. 8 , a front portion  11 B of the airbag  11  is folded such that the front portion is superposed on the top of the container  12  and is further folded zigzag (i.e. in an accordion type fold) into a block shape. The folds formed by this folding of the front portion  11 B extend in the left-to-right direction. The front portion  11 B in the block shape is turned by 180° over the top of the container  12 , whereby the folded portions of the airbag are entirely piled on the top of the container  12  ( FIG. 9 ). Then, this piled portion is slid (parallel movement) into the container  12  (see the arrow Z in  FIG. 9 ). The lid is put on the container  12 , thereby assembling the airbag apparatus. As shown in  FIG. 9 , the front portion  11 B folded zigzag is disposed above (on the outlet side of the container  12 ) the rear portion  11 A which is also folded zigzag. Further, as shown in  FIG. 9 , a gas passage W for introducing gas from the inflator  13  into the front portion  11 B and the rear portion  11 A exists at the vehicle front side (windshield side) in the piled body of the airbag. The direction of the gas passage W is completely opposite to the direction of arrow Z to extend along the front side (windshield side) of the piled body in a state that the folded bodies  11 A,  11 B are pushed out from the container  12  but still piled on each other. 
   As shown in  FIG. 10(   a ), the airbag apparatus is installed in an upper portion of the instrument panel  20  which extends substantially horizontally or slightly downward toward the rear side of the vehicle. As the inflator  13  is actuated to spout out gas in the event of a vehicle collision, the lid is torn to open and the airbag  11  starts to inflate as shown in  FIGS. 10(   a ),  10 ( b ),  10 ( c ) in this order. In this case, the front portion  11 B and the rear portion  11 A are pushed out from the container  12  in the still piled state as shown in  FIG. 9  by gas pressure from the inflator  13 . The gas flows through the gas passage W in the direction opposite to the direction of arrow Z of  FIG. 9  so as to flow preferentially into the front portion  11 B to inflate the front portion  11 B, whereby the airbag  11  first receives the head of an occupant P as shown in  FIG. 10(   b ). Then, as shown in  FIG. 10(   c ), the rear portion  11 A of the airbag  11  is also inflated so as to receive the upper body of the occupant P. In this manner, the airbag apparatus has a behavioral characteristic of first receiving the head of the occupant P. 
   The aforementioned embodiment should be taken as an example of the present invention. The present invention can be adopted to another form not illustrated. For example, though the left portion  11 L is folded before the right portion  11 R is folded as shown in  FIGS. 5–7  in the aforementioned embodiment, the right portion  11 R may be folded before the left portion  11 L is folded, or the left portion  11 L and the right portion  11 R may be folded simultaneously if possible. The left portion  11 L and the right portion  11 R may be folded zigzag (i.e. in an accordion type fold). 
   As described above, the present invention provides an airbag apparatus having such a behavioral characteristic that a front portion of an airbag is inflated earlier than a rear portion of the airbag. 
   Given the disclosure of the present invention, one versed in the art would appreciate that there may be other embodiments and modifications within the scope and spirit of the invention. Accordingly, all modifications attainable by one versed in the art from the present disclosure within the scope and spirit of the present invention are to be included as further embodiments of the present invention. The scope of the present invention is to be defined as set forth in the following claims.