Patent Publication Number: US-RE39629-E

Title: Side air bag

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a side air bag which expands near a window of a vehicle at a collision of the vehicle, and particularly relates to a side air bag formed by a woven fabric such as a hollow weave. 
     An air bag apparatus for a vehicle is an apparatus for constraining a vehicle occupant, i.e. passengers and a driver, by inflating and expanding an air bag at a time of collision of the vehicle, and generally comprises an inflator (a gas generating device) for inflating the air bag in response to a signal from a sensor for detecting a  predetermined collision characteristics of the vehicle. The air bag is inflated by gas from the inflator. The air bag is formed in a bag shape by a woven fabric. 
     A so-called hollow weave, in which two fabrics are interwoven as a  one woven fabric and  by a yarn, partly constituting each of the two fabrics, partly to form a common textile structure so as to combine  of the interwoven two fabrics, is generally known in weaving for producing industrial materials and the like. There are some examples in which the woven fabric of the hollow weave is used for ane  an air bag, for example, JP-A-02158442 (Japanese Patent Unexamined Publication No. 2-158442) describes a bag formed by the hollow weave. JP-A-03128743 describes that  connection of the  woven fabric  fabrics in the  a peripheral portion is performed  by a single-layer joint textile structure for connection , and similar matter is described in PCT  WO 90/09295 (PCT/GB 90/00215, Japanese Patent National Publication of translated version 4-504988) . 
     However, the air bags of these references are basically uncoated bags which are woven by hollow weave. The references disclose that air bags can be partly coated or coated, but have no intention for reducing an air-permeability of a fabric by coating. 
     On the other hand, whileWhile the conventional air bag apparatus includes both an air bag for a driver&#39;s seat,and an air bag for a front-passenger seat and the like, a common point thereof is to constrain an occupant from the front within a short time such as some milliseconds to some tentens of milliseconds. 
     Recently, as an air bag apparatus, inIn addition to the above air bag apparatus which constrains the occupant from the front, a side air bag apparatus for constraining the occupant from a left-hand side or a right-hand side is developedknown. 
     The side air bag is structured such as to be housed in a side structure of the vehicle such as a front pillar, a roof side rail portion, a center pillar, a quarter pillar and the like, and as to receive  receives a gas supplied from an inflator fixed to a bottom part of the front pillar or a neighboring side panel and the like at a time when the vehicle receives a predetermined impact from the side surface thereof so that the air bag inflates and expands near the window along a side surface of a cabin, thereby restraining the occupant from moving in a lateral direction of the vehicle. 
     A point in which theThe side air bag is greatly  different from the above typical-type conventionaldescribed air bag isin that a long expanding time, such as some seconds, is required to be continued for constraining the occupant at a time of overturning of the vehicle. 
     Accordingly, the typical-type conventional  above described air bag has a function of inflating and expanding for a short time, such as some milliseconds, to some ten  tens of milliseconds and of discharging the gas while constraining the occupant. In contrast to this, in the newly suggested  side air bag, to meet a constraint requirement of the occupant at a time of overturning of the vehicle, it is required to set  have an expansion holding time to  for a relatively long time such as some seconds. 
     Further, the typical-type conventional  air bag mentioned above for front collision operation is housed in a relatively large size trim part of the vehicle, such as a horn pad, an instrumental panel, a seat or the like, and a cross sectional area of the air bag in a direction of folded and piled fabrics is about 20 to 150 cm 2 . However, in the side air bag, since it is housed in a column shaped pillar, a roof side rail portion or the like, there is a problem that the side air bag has to be folded in a relatively small cross sectional area such as 4 cm 2  so as to be housed . 
     SUMMARY OF THE INVENTION 
     The present invention is made by taking the above described problems into consideration and an object of the present invention is to provide a side air bag housed in a side structure such as a pillar, a roof side rail portion or the like of a vehicle in which an air tightness thereof is improved so that an inflation holding time can be  is protracted and a bulk of a folded air bag is reduced so as to improve a housing performance for  mounting into the side structure. 
     In accordance with a first aspect of the present invention which is suitable for the above object,  there is provided a side air bag having a bag portion formed by connecting two woven fabrics in an outward peripheral portion and having a mechanism for expanding the  a bag portion alongside a window of a vehicle, wherein a connecting portion for connecting the two woven fabrics is formed by weaving a textile structure having a common yarn constituting both fabrics, and the whole of the  bag portion is sealed by an air non-permeable  impermeable coating material. 
     In the side air bag having the above structure, a sewing process and a sealing process for sealing stitch perforations in conventional manufacturing methods can be omitted so that an air bag having an air tightness for maintaining inflation duration an  on the order of some seconds can be  is economically manufactured. Further, a side air bag that can meet  meets a requirement for an occupant constraint at a time of overturning of the vehicle can be  is obtained. 
     In the conventional air bag, the sewn portion has a thickness of two fabrics and upper and lower threads of  a sewing thread, and in addition to this, a tape for sealing the  a perforation of the sewing thread is required. In contrast to this, in accordance with the above side air bag, the connecting portion along the outer periphery of the bag portion can be made thinner than a combined thickness of the two fabrics due to the structure of the textile structure.and further  Furthermore, a sewing thread and a tape thickness  for sealing the perforation of the sewing thread is not required so that the connecting portion becomes significantly thinner in comparison with the conventional air bag. Accordingly, a bulk in  of a folded state is reduced so that the air bag can be housed in the side structure such as an elongated and narrow pillar, roof side rail portion and the like in a compact manner. 
     Further, in accordance with a second aspect of the present invention, there is provided a side air bag side  having a bag portion formed by connecting two woven fabrics in an outward peripheral portion and housing the bag portion in a side structure of a vehicle, such as a pillar and a roof side rail portion, wherein a connecting portion connecting the woven fabrics is formed by weaving, as  a common textile structure having a common yarn constituting both fabrics, both fabrics or the . The common textile structure portion is extended further outward from the connecting portion so as to form a mounting portion for mounting in the side structure, and further all said bag portion is sealed by an air non-permeable  impermeable coating material. 
     In the side air bag having the above structure , as in the same manner as the above,  an air tightness for maintaining inflation duration on an order of some seconds can also be maintained, and further, a  housing performance for housing into  in the side structure such as the pillar and the like is improved. In addition to this, a housing performance for  housing a mounting portion into the pillar and the like can be particularly improved, while the mounting portion can be formed without sewing a specially prepared fabric for the mounting. 
     Accordingly, in the case that the peripheral portion of the connecting portion is extended so as to integrally form the mounting portion for mounting to the pillar and the like, if both of the two woven fabrics are extended from the portion of the common textile structure, a mounting portion formed of two sheets piled without a continuous stitch can be formed. and further  Furthermore, if one of the woven fabrics is extended, the mounting portion having an improved housing performance  can be formed with  having a single sheet thickness to improve stowability. Further, if the portion of the common textile structure is extended as it is, the  a mounting portion having a higher  greater strength can be  is formed. 
     In the case that the mounting portion is consisting  consists of two fabric sheets, after separating up these  the two fabrics so as to be opened  sheets, if the  a coating is also applied to an inner side between the two fabrics  fabric sheets in the mounting portion, that is, to and around the peripheral edge of the common textile structure, the sealability of the mounting portion can be  is further improved. 
     In the side air bag in accordance with each of the above inventions, a linear connecting portion, for  partitioning the bag portion in parallel with a flow direction of an inflator gas, is formed to connect the two woven fabrics constituting  fabric sheets at a position of the bag portion, at  corresponding to a center region of the bag portion, and wherein the . The connecting portion for partitioning  is formed by weaving as  a textile structure having a common constituting yarn for  of both fabrics  of the two fabric sheets. Accordingly, an appropriate expansion shape can be  is easily set, and the thickness of the connecting portion for partitioning becomes  is thinner than the  a thickness of the two fabrics  fabric sheets so that the housing performance for housing  in the side structure, such as the pillar and the like, can be is improved. 
     Further, the connecting portion for partitioning  at the center region of the bag portion may be formed by a stitch, and an inflator-side terminal portion of the stitch may be formed as  in a U-shape or a circular shape. In this case, the inflating shape can be  is controlled and a stress concentration on the inflator-side terminal portion at a time of inflation of the air bag can be eased. 
     Still further, an opening for introducing an inflator gas can be formed in a part of the connecting portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view which shows a side air bag in accordance with a first embodiment of the present invention; 
         FIG. 2  is a cross-sectional view along a line X—XII—II in  FIG. 1 ; 
         FIG. 3  is a cross-sectional view which shows an embodiment of a mounting portion of the air bag; 
         FIG. 4  is a cross-sectional view which shows another embodiment of the mounting portion of the air bag; 
         FIG. 5  is a cross-sectional view which shows a coatingan area to be coated inside the mounting portion; 
         FIG. 6  is a front view which shows a side air bag in accordance with a second embodiment of the present invention; 
         FIG. 7  is a cross-sectional view along a line Y—YVII—VII in  FIG. 6 ; 
         FIG. 8  is a front view which shows a side air bag in which a connecting portion for partitioning  is formed by a  sewing together two fabric sheets; 
         FIG. 9  is an enlarged view which shows a shape of a terminal portion of a stitch; 
         FIG. 10  is an enlarged view which shows another embodiment of the shape of terminal portion of a stitch; 
         FIG. 11  is a front view of an air bag which shows an embodiment of an opening for mounting an inflator; and 
         FIG. 12  is a cross sectional view along a line Z—ZXII—XII in FIG.  11 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An embodiment in accordance with the present invention will be explained below with reference to the accompanying drawings. however, However, the present invention is not limited to this  embodiments in the drawings. 
       FIGS. 1 and 2  show a side air bag A in accordance with a first embodiment of the present invention and in these drawings, in order to show a used state of the side air bag, a part of a vehicle and an occupant are respectively shown by a chain line. 
     When a sensor detects a predetermined impact from a side surface of the vehicle, the side air bag A inflates and expands near a window W along a side surface of a cabin in response to a signal from the sensor, thereby constraining mainly a head of an occupant M from a left-hand side or right-hand side. The side air bag A also works at a time of lateral tumbling of the vehicle. 
     The air bag A is structured such that a bag portion  3  is formed by connecting two woven fabrics  1  and  2  which are  each formed by a plain weaving, at an outer periphery thereof, as shown in the drawings. In this example, a front edge and an upper edge of the bag portion  3  is formed such as to substantially correspond to a curve extending from a front pillar F to a roof side rail portion R of the vehicle and to substantially form a shape of a parallelogram in an expanded form along the window W so as to be naturally folded and housed in a side structure of the vehicle such as the front pillar F, the roof side rail portion R and the like. 
     Further, a front end portion of the air bag A is provided with an opening  9 , for mounting an inflator  10 , a part of which is extended  and extends in pipe-like shape. to be opened, and for example, an The inflator  10  is mounted to a bottom part of the front pillar F and is connected thereto  to the opening  9 . 
     The air bag A is formed by a hollow weaving, in which a connecting portion  4  disposed along an outer periphery of both of the both  woven fabrics  1  and  2  is woven as a textile structure having a common yarn (a warp yarn or a weft yarn) constituting each of the both  two woven fabrics, that is, by a   1  and  2 . Thus, the textile structure is of a single layer construction. Further, by extending both of the woven fabrics  1  and  2  outward from the connecting portion  4 , a mounting portion  5  for mounting to the  a side structure, such as the front pillar F, the roof side rail portion R and the like, is integrally formed. A mounting hole  Mounting holes  6  are for a  receiving fixing bolt or a rivet is  bolts or rivets and are formed on  in the mounting portion  5 . 
     Still further, all the surface of the bag portion  3 , including the outer peripheral connecting portion  4 , is coated for sealing  and sealed by an air non-permeability  impermeable coating material (not shown) such as a silicone rubber, a chloroprene rubber or the like so as to improve an air tightness to provide an expansion holding time for  of about 5 seconds. 
     The mounting portion  5  can be formed by the two woven fabrics  1  and  2  as shown in  FIG. 2 , and can be also formed by extending any one of the fabrics  1  and  2  as shown in  FIG. 3 , or by extending, as it is,  the common textile structure portion formed by a hollow weave from the connecting portion  4  as shown in FIG.  4 . 
     In the case thatReferring to  FIG. 5 , the mounting portion  5  is formed by the two fabrics  1  and  2 , and the air tightness of the bag portion  3  can be improved by coating an inner side  5 a of the fabric in the mounting portion  5 with the coating material, particularly near the common textile structure portion by the coating material (not shown) as shown in  FIG. 5  . 
     A side air bag in accordance with a second embodiment of the present invention is shown in  FIGS. 6 and 7 . 
     TheAn air bag AA′ in accordance with thisthe second embodiment is provided with a connecting portion  7  for partitioning the air bag A′, in addition to the structure of the side air bag A in accordance with the first embodiment. In  FIGS. 6 and 7 , the same reference numerals designate the same elements as in FIG.  1 . 
     Accordingly, the side air bag A  A′ in accordance with the second embodiment is structured as follows. The connecting portion  4  along the outer periphery of the two woven fabrics  1  and  2  is made of the common textile structure by a hollow weave so as to form the bag portion  3 . Two linear connecting portions  7  for partitioning , which are substantially parallel to a flow direction of the inflator gas, are formed to connect the two woven fabrics  1  and  2 ,  at the center region of the bag portion  3 , as shown in the drawing. Further, the connecting portion  portions  7  for partitioning is  are woven as formed by  the textile structure having a common yarn constituting both of the both  woven fabrics  1  and  2 , as  in the same manner as that of the connecting portion  4 . 
     The connecting portion  7  for partitioning is provided for the purpose of controlling the expanding shape of the air bag during an inflating process so that a suitable inflated shape can be  is set. Further, the thickness thereof is thinner than the combined thickness of the two fabrics, as  in the same manner as that in the outer peripheral connecting portion  4 , so as to be . Thus, the air bag A′ is easily folded and housed in the pillar and the like. 
     In another embodiment, for example as shown in  FIG. 8 , the  a similar connecting portion  7  for partitioning can be   7 a is formed by sewing first and second center connecting portions  7 a,  7 a, at upper and lower levels, which are discontinuous with each other and with the outer peripheral connecting portion  4  such that a first expansible region is formed between said first and second center connecting portions  7 a,  7 a and has first and second ends, a second expansible region is formed between said first center connecting portion  7 a at the upper level and the peripheral connecting portion  4  and has first and second ends, a third expansible region is formed between the second center connecting portion  7 a at the lower level and the peripheral connecting portion  4  and has first and second ends, and the first and second ends of each of the first expansible region, the second expansible region, and the third expansible region respectively communicate with each other. In this case, in order to ease a stress concentration during expansion of the air bag, as respectively shown in FIG.  9  and  FIG. 10 , it is preferable to form a  an inflator-side terminal portion  8  of stitching  (a terminal portion  8  of stitch  stitched close to the inflator) as  by stitching a circular shape having a diameter of about 3 to 30 mm or a U-shape having a width of about 3 to 30 mm. Further, a perforation of the stitch does  perforations formed by the stitching do not deteriorate the air tightness of the air bag since the  coating using  the coating material on the air bag is performed in a later step. 
       FIGS. 11 and 12  show another embodiment of the inflator mounting opening portion  9   9 a in the air bag A. 
     In each of the above embodiments, the opening portion   9  is formed by extending a part of the bag portion  3  in a pipe-like shape so as to open the part  to an opening of the connecting portion  4 ; however, the . However, an opening  9    9 a can be formed on one of the woven fabrics  1  and  2  by a  laser cutting and the like, as shown in the drawings, after a bag portion having no opening is formed in  by the connecting portion  4 . 
     The side air bag A  bags in accordance with each of above-described  the above embodiments is  are formed by a so-called hollow weave, as which is the common textile having the  structure combining the two fabrics and having common constituting yarn in  of the two fabrics. The hollow weaves forms the connecting portion  4  at the outer periphery of the bag portion and the surface of the air bag is coated. Therefore, an air bag can be manufactured without the conventional sewing step and the sealing step for sealing the stitch perforation  the perforations cause by stitching. Thus, the air bag which  can maintain a long inflation duration,  for constraining the occupant at a time of overturning of the vehicle, and can be easily and economically manufactured. 
     Further, the connecting portion  4  can be made thinner than the combined thickness of the two woven fabrics, while the sewing thread and the tape for sealing the stitch perforation  perforations from stitching are not required. For this reason, the connecting portion  4  is made thinner than that of the conventional air bag and the air bag can be easily folded and housed in the side structure of the vehicle such as the elongated and narrow pillar and the like. 
     Further, since the mounting portion to  for mounting to the side structure can be integrally formed by the fabric extending from the circular woven  common textile structure or the circular woven structure portion , it is unnecessary to sew the fabric for the mounting portion separately and the mounting portion can be  is formed thin so as to improve the housing performance, and  stowability. Furthermore, a number of the  parts and the  manufacturing steps can be reduced so that the economical  economic efficiency can be further improved. 
     Whereas the embodiments of the present invention have been explained as above, the side air bag of the present invention can be housed and mounted to a side structure of the vehicle other than the pillar or the roof side rail portion.