Patent Publication Number: US-2005116450-A1

Title: Airbag apparatus

Description:
BACKGROUND  
      The present invention relates to airbags for protecting the head of a vehicle occupant, and more in detail, it relates to an airbag to be inflated along a side door window.  
      As an airbag for protecting the head of an automobile occupant, there exists a curtain airbag that is arranged in the vicinity of the boundary corner between a ceiling and a side panel of an automobile compartment so as to inflate along a window of a side door by gas induced from a gas inlet.  
      When an automobile having the curtain airbag apparatus is collided side-on or rolls sideways, the curtain airbag inflates toward the vehicle bottom along the side of the vehicle compartment (a door and a pillar, for example) so as to protect the head of an occupant while preventing the occupant from being thrown out of the vehicle when the door is open.  
      A type of curtain airbag apparatus is disclosed in U.S. Pat. No. 6,237,938 (incorporated by reference herein). The patent discloses a curtain airbag inflating along the compartment panel. The disclosed airbag apparatus includes a guide member along the rear edge of the airbag. In order to prevent the rear end of the curtain airbag moved downward from returning upward, the curtain airbag is provided with latches arranged along the substantially entire length of the track at equal intervals.  
      Japanese Unexamined Patent Application Publication No. 2003-81048 (incorporated by reference herein) discloses a head-protecting airbag apparatus in that the rear of an inflated head-protecting airbag is pulled backward so as to generate a strong tension along the lower boundary of the head-protecting airbag.  
     SUMMARY OF THE INVENTION  
      According to an embodiment of the present invention, the movement of an occupant body toward the outside of a vehicle can be suppressed by generating a tension along the lower boundary of the airbag.  
      A head-protecting airbag according to the present invention is capable of inflating along a side surface of a vehicle compartment, and includes tension-applying mechanism for applying a tension to the inflated airbag along a lower boundary of the airbag, wherein when the airbag is inflated. According to an embodiment of the present invention, the airbag has a vertical width so as to have a lower-border height of 82.5 mm or less from a beltline.  
      A head-protecting airbag apparatus according to the present invention includes the head-protecting airbag according to the present invention and an inflator for inflating the head-protecting airbag.  
      According to an embodiment of the present invention, the tension-applying mechanism may include a linear member extending along a lower boundary of the inflated head-protecting airbag and a means for applying a tension to the linear member, and when the head-protecting airbag is inflated, the linear member may preferably be positioned at a height of 82.5 mm or less above from the beltline of the vehicle.  
      In the head-protecting airbag, the airbag apparatus, and the vehicle according to the present invention, when the head-protecting airbag is inflated, its lower boundary is positioned directly above (less than 82.5 mm) the beltline (the lower edge of the side window, i.e., the upper edge of the door panel), and a tension is applied to the lower boundary of the airbag as well. In such a manner, by reducing the space between the lower boundary of the inflated head-protecting airbag and the beltline to a value of less than half of the diameter (165 mm) of the spherical head of a dummy doll for a bump test, the movement of the occupant body, the head in particular, toward the vehicle outside, is sufficiently suppressed.  
      Especially when the linear member for applying a tension to the airbag is positioned within 82.5 mm above the beltline during the inflation of the airbag, the movement of the occupant body toward the vehicle is further sufficiently suppressed.  
      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  is a side view of an inside of a vehicle compartment having an airbag according to an embodiment,  FIG. 1 ( a ) showing a state of the airbag before inflation and  FIG. 1 ( b ) showing an inflated state of the airbag.  
       FIG. 2  is a sectional perspective view of the rear of the inflated airbag.  
       FIG. 3  is a sectional view at the line III-III of  FIG. 2 .  
       FIG. 4  is a structural drawing of a one-way pulley.  
       FIG. 5  is a sectional perspective view of the rear of an airbag according to another embodiment.  
      FIGS.  6 ( a ) and  6 ( b ) are a side views of the inside of a vehicle compartment having an airbag apparatus according to still another embodiment  FIG. 6 ( a ) shows a state that the airbag apparatus is mounted on a vehicle body  10 ′ of a type with a small overhang, such a mini-van; and  FIG. 6 ( b ) shows the inflated state of the airbag.  
      FIGS.  7 ( a ) and  7 ( b ) are perspective views of an airbag apparatus having such a guide member so as to generate a tension in the lower boundary of the head-protecting airbag;  FIG. 7 ( a ) shows a folded state of the airbag; and  FIG. 7 ( b ) shows a state that the inflation of the airbag is completed. 
    
    
     DETAILED DESCRIPTION  
      This head-protecting airbag (may be simply called as an airbag)  1  is provided along a roof side, for example, between an A-pillar and a C-pillar of an automobile in a folded state, and when the vehicle is side-on collided or rolls sideways, the airbag is inflated and deployed along a side of vehicle compartment like a curtain so as to receive heads of occupants sitting on front and rear seats of the automobile cabin, preventing the heads from striking on the cabin side or being thrown out of a window.  
      The airbag  1  is formed by overlapping two sheets  2  and  3  being substantially identical in shape and making up two surfaces facing the compartment side and the inside the compartment, respectively, so as to combine the peripheral edges of the sheets  2  and  3  together with a linear seam  4 . Although not shown, the airbag may also be divided into a plurality of small chambers by stitching the sheets  2  and  3  together so that the bag inside is further divided into several divisions or by providing panels for parting the bag inside.  
      A duct  5  is extended from the rear of the airbag  1  for inducing gas. To the duct  5 , an inflator  6  is connected for inflating the airbag  1 .  
      A plurality of projection pieces (selvages)  7  extend from upper and front borders of the airbag  1 , each projection piece  7  having a bolt insertion-hole  7   a  for fastening the airbag  1  to a vehicle body. The airbag  1  is fastened to a roof side-rail  11  and an A-pillar  12  with the projection pieces  7  in a slenderly folded state so as to extend in a longitudinal direction of the vehicle body. Reference numeral  14  denotes a B-pillar.  
      The folded body of the airbag  1  arranged in such a manner is covered with a cover member, such as a pillar trim and a roof trim, which is adapted to be forced open by the inflating airbag  1  so as to allow the airbag  1  to be deployed into the vehicle compartment. In  FIG. 1   b ), the cover member is not shown for brevity.  
      The airbag  1  is provided with wire holders  20  arranged along the lower edge at predetermined intervals. The wire holder  20  is made of a small cloth piece with the upper and lower sides respectively sewn on the airbag  1  with sewing threads  21 . Between the respective wire holders  20  and the airbag  1 , a wire (a wire rope woven with synthetic fiber according to the embodiment)  22  is inserted through. The front end of the wire  22  is stuck to the lower front extremity of the airbag  1  by sewing, and is further fixed to the A-pillar  12  with fastening members such as bolts together with the projection piece  7  at the lower front extremity.  
      The rear end of the wire  22  extended from the lower rear extremity of the airbag  1  is stretched around a one-way pulley  30 , and then routed upward along the C-pillar  13 . A roof-side rail  11  is provided with pulleys  41  and  42  respectively attached to a rear portion and a portion slightly forward than the former. The wire  22  is stretched around the rear pulley  41  so as to proceed forward, and then stretched around the front pulley  42  so as to proceed downward. The wire  22  is routed to the lower end of the airbag  1  passing through the airbag  1  adjacent to a vehicle door, so that its end is stuck to the lower end of the airbag  1  such as by sewing and the like.  
      The one-way pulley  30 , as shown in  FIG. 4 , includes a thin box-like case  31 , a pulley body  32  arranged inside the case  31 , and a guide surface  33  extending in an arch shape along the external periphery of the pulley body  32 . The pulley body  32  is rotatably supported to the case  31  with a shaft  34  therebetween. The shaft  34  is eccentric relative to the pulley body  32 . The pulley body  32  is provided with an arch-shape bulged portion  32   a  formed farther from the shaft  34  so as to face the guide surface  33 .  
      Passage holes  35  and  36  for the wire  22  are formed on the front and upper surfaces of the case  31 , respectively. The point in the arch-shape bulged portion  32   a  positioned farthest from the shaft  34  is located adjacent to the passage hole  36 . Hence, when the wire  22  moves from the passage hole  35  toward the passage hole  36  as shown in Arrow of  FIG. 4 , the arch-shape bulged portion  32   a  moves toward the passage hole  36  accompanied by the wire  22 , and the space between the pulley body  32  and the guide surface  33  increases so that the wire  22  passes through the one-way pulley  30  freely. On the other hand, when the wire  22  is to move in a direction opposite to the arrow direction of  FIG. 4 , the arch-shape bulged portion  32   a  is to move toward the passage hole  35  accompanied by the wire  22 , so that the wire  22  is pinched between the arch-shape bulged portion  32   a  and the guide surface  33 , resulting in stopping of the wire  22 .  
      The operation of a head-protecting airbag apparatus having the airbag  1  structured in such a manner will be described.  
      Upon a side-on collision or sideway rolling of an automobile, the inflator  6  is operated so as to inflate the airbag  1  by supplying gas into the airbag  1 . The airbag  1  pushes the cover member open so as to extend downward along a side of the vehicle compartment like a curtain and to inflate between vehicle occupants and the side of the vehicle compartment. Owing to the inflated airbag  1 , the vehicle occupants are prevented from directly string pillars and window glass or being thrown out of the vehicle.  
      When the head-protecting airbag is inflated to downward deploy, the rear end of the wire  22  is pulled to move in the arrow A direction of  FIG. 2 , so that the wire  22  becomes strongly tense along the lower boundary of the airbag  1 . According to the embodiment, the wire  22  in a strongly tense state is positioned within 82.5 mm above a beltline BL, preferably within 80 mm, and more preferably within 70 mm in particular. In such a manner, the lower boundary of the airbag  1  descends just above the belt line BL so as to have a strong tension applied by the wire  22 , so that the movement of vehicle occupants toward the vehicle outside is sufficiently suppressed. Since the one-way pulley  30  is adopted especially according to the embodiment, the slack of the wire  22  along the lower boundary of the airbag  1  is removed, so that the movement of vehicle occupants toward the vehicle outside is sufficiently suppressed for a long time.  
      According to the embodiment, a plurality of the wire holders  20 , each made of a small cloth piece, are attached in the bottom of the airbag  1 . As shown in  FIG. 5 , the airbag  1  is provided with a seam  25  formed in parallel to the seam  4  formed along the lower edge of the airbag  1  so as to form a tunnel wire path  21  between the seam  4  and  25 . The wire  22  may also be inserted through the wire path  21 .  
      According to the embodiment, a vehicle body  10  is a sedan type; alternatively, other types may incorporate the present invention.  FIG. 6 ( a ) shows a state that the airbag apparatus is mounted on a vehicle body  10 ′ of a type with a small overhang, such a mini-van; and  FIG. 6 ( b ) shows the inflated state of the airbag  1 ′. According to this embodiment, since a space for arranging the inflator is small in a C-pillar  13 ′, the inflator  6  is arranged in the roof side-rail  11 . Other structures in  FIG. 6  are the same as in  FIG. 1 , and like reference characters designate like elements. The airbag  1 ′ also has a strong tension applied by the wire  22  along the lower boundary when inflated, while the wire  22  is adapted to be positioned within 82.5 mm above the beltline BL, so that the movement of vehicle occupants toward the vehicle outside is sufficiently suppressed.  
      As described above, according to an embodiment of the present invention 82.5 mm is specified as a preferential distance for positioning the wire above the beltline of the vehicle. However, the scope of the present invention is not limited to the 82.5 mm distance. For example, according to various embodiments of the present invention, the wire may be positioned at any suitable height between 82.5 mm above the beltline and the beltline including, for example, approximately 60 mm, 45 mm, 30 mm, or 15 mm.  
      Any of the embodiments described above is an example of the present invention, and structures other than ones shown in the drawings may incorporate the invention. For example, the wire  22  may be adapted to have a tension along the lower boundary of the airbag by pulling the lower rear end (or front end) of the airbag.  
      Also, according to the present invention, a guide member may be provided for guiding longitudinal ends of a curtain airbag downward deploying along the side of a vehicle compartment so as to generate a tension along the lower boundary of the airbag by the guide member. In this case, the guide member nay be provided with an anchor portion formed by bending or curving the lower portion of the guide member so as to stop the ends of the curtain airbag descending along the guide member from returning upward. Forming the anchor portion by bending or curving the guide member in such a manner is made by very simple and relatively cost effective process in comparison with conventional methods such as disclosed in the aforementioned patent.  
       FIG. 7  is a perspective view of an airbag apparatus having such a guide member so as to generate a tension in the lower boundary of the head-protecting airbag;  FIG. 7 ( a ) shows a folded state of the airbag; and  FIG. 7 ( b ) shows a state that the inflation of the airbag is completed.  
      According to this embodiment, a head-protecting airbag  51  is arranged along a roof side portion of a vehicle (boundary between a ceiling and a side of a vehicle compartment)  52  in a slenderly folded state in a longitudinal direction. When an automobile is collided side-on or rolls sideways, the airbag  51  starts inflating by gas from the inflator so as to inflate and deploy toward the bottom of the vehicle body along the side of the vehicle compartment, such as doors and pillars. The airbag  51  is provided with selvages  53  formed in the upper border. By inserting bolts  55  into bolt-insertion holes of the selvages  53  so as to be screwed into tapped holes of the roof side portion  52 , the airbag  51  is anchored to the roof side portion  52 .  
      To a C-pillar  57  of an automobile, a guide member  58  is attached for guiding the rear end of the airbag  51  along the C-pillar  57  when the airbag  51  is inflated along the C-pillar  57  toward the bottom of the vehicle body. The guide member  58  includes a rod-like guide portion  59  extending along the C-pillar  57  in the vertical direction of the vehicle body, upper and lower fixing parts  60  and  61  for respectively fixing upper and lower ends of the guide portion  59  to the C-pillar  57 , and temporary anchor portions  62  and  63  for temporarily anchoring the upper and lower fixing parts  60  and  61  to temporary openings  73  and  74  of the C-pillar  57 , respectively, when the guide member  58  is attached to the C-pillar  57 .  
      The airbag  51  is provided with a loop connection band  64  attached to the vicinity of the lower rear end corner, and the rear end is connected to the guide member  58  by inserting the guide portion  59  into the connection band  64 .  
      The guide portion  59  is made of a pipe-like member. The lower part of the guide portion  59  is bent in a substantial crank-shape so as to form an anchor portion  59   a  made of an L-shaped corner protruding toward the airbag  51  for the connection band  64 . A substantial horizontal portion  59   b  linking with the anchor portion  59   a  functions as a stopper for stopping the connection band  64  from moving to a position lower than the anchor portion  59   a.    
      The guide member  58  is fixed to the C-pillar  57  by inserting bolts  69  into bolt insertion holes provided in the fixing parts  60  and  61  so as to be screwed into tapped holes formed in the C-pillar  57 , respectively.  
      In the airbag apparatus shown in  FIG. 7  and structured in such a manner, when the airbag  51  starts inflating by the operation of the inflator, while being guided by the guide member  58  with the connection band  64  therebetween, the airbag S 1  is deployed toward the bottom so as to complete the inflation as shown in  FIG. 7 ( b ).  
      According to the embodiment, the guide member  58  is arranged so that the higher a portion  59   c  upper than the anchor portion  59   a  is, the more it is located rearward the vehicle. Hence, when the airbag  51  is completed to inflate, the connection band  64 , which is the rear end of the airbag  51 , is prevented from upward returning. That is, when the airbag  51  is inflated, the length in the longitudinal direction is reduced by a tension applied to the external surface so that the rear end is pulled forward. In the completed step of the inflation shown in  FIG. 7 ( b ), the connection band  64  cannot move upward and rearward along the guide portion  59  so as to remain at the anchor portion  59   a , thereby generating a strong tension along the lower boundary of the airbag  51 .  
      Also, according to the embodiment, in a completed state of inflation of the airbag  51 , a space d between the lower boundary of the airbag  51  and the beltline BL ( FIG. 7 ( b )) is 82.5 mm or less Thereby, the movement of the head of an occupant toward the vehicle outside is sufficiently suppressed.  
      As described above, according to an embodiment of the present invention 82.5 mm is specified as a preferential distance for positioning the bottom of the inflated airbag above the beltline of the vehicle. However, the scope of the present invention is not limited to the 82.5 mm distance. For example, according to various embodiments of the present invention, the bottom of the inflated airbag may be positioned at any suitable height between 82.5 mm above the beltline and the beltline including, for example, approximately 60 mm, 45 mm, 30 mm, or 15 mm.  
      The priority application, Japanese Patent Application No-2003-403197 filed Dec. 2, 2003, is hereby incorporated by reference herein in its entirety.  
      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.