Patent Publication Number: US-2005134022-A1

Title: Curtain airbag device

Description:
BACKGROUND  
      The present invention relates to curtain airbag devices provided with curtain airbags that are capable of being deployed along inner side surfaces of vehicle cabins.  
      In a vehicle provided with a curtain airbag device, when the vehicle is involved in, for example, a side-on collision or rollover, curtain airbags are deployed downward along an inner side surface (for example, a door and a pillar) of the vehicle cabin so as to protect the head of the vehicle occupant and to keep the vehicle occupant inside the vehicle cabin.  
      U.S. Pat. No. 6,237,938 discloses a guide member provided on a C pillar for guiding downward (along the pillar) a rear portion of a curtain airbag, which is inflatable along the inner side surface of the vehicle cabin. Moreover, the guide member in U.S. Pat. No. 6,237,938 (incorporated by reference herein) includes a track having a box-shaped cross-section and a slider (as referred to as an “element”) that is movably arranged in the track in the longitudinal direction of the track. The rear end portion of the curtain airbag is tied to the slider. To prevent the rear edge portion of the curtain airbag, which is moved downward, from being retracted upward, latches are arranged at regular intervals along substantially the entire length of the track. The top and bottom ends of the track are provided with mounting flanges; each of the flanges is fixed to the C pillar with a bolt or a screw.  
      Japanese Unexamined Patent Application Publication No. 2001-270413 (incorporated by reference herein) discloses a structure in which a gas generator is inserted into a gas inlet of a curtain airbag. The gas generator and the gas inlet are clamped together with a metal fitting at the periphery so as to be connected to each other.  
      Unfortunately, as a result of the structures provided in U.S. Pat. No. 6,237,938 and Japanese Unexamined Patent Application Publication No. 2001-270413, when the curtain airbag is inflated, gas may leak from the curtain airbag through the interface between the gas inlet and the gas generator. As a result, a high (also referred to as “elevated”), i.e., greater than atmospheric pressure, internal pressure of the curtain airbag cannot be maintained for a long period of time, e.g., several hours.  
      Accordingly, the present invention has been made in light of the aforementioned problems. It is an object of the present invention to provide a curtain airbag device in which gas leakage from a gas inlet of a curtain airbag is prevented (or at least greatly inhibited) so as to maintain an elevated internal pressure of the curtain airbag for a long period of time.  
     SUMMARY  
      According to an embodiment of the invention curtain bag device is provided. The device includes: a curtain airbag having a gas inlet, wherein the curtain airbag is configured to be deployed downward along an inner side surface of a vehicle cabin; a gas generator configured to supply gas from the gas inlet into the curtain airbag; and an insertion block composed of a duct that communicates with the gas generator. The insertion block and the gas inlet are clamped with a clamp from the outside of the gas inlet so as to be connected to each other. The gas generator or the insertion block is inserted into the gas inlet. A seal is disposed on the inner surface of the gas inlet.  
      In a further embodiment of the curtain airbag, the seal may be composed of an elastic adhesive or soft rubber.  
      In another further embodiment of the curtain airbag, the curtain airbag may be formed of two layers of sheets connected to each other at least at the periphery. Further, the gas inlet may be formed by connecting the sheets at a linear connected portion. The seal may be disposed on portions in the inner surface of the gas inlet along the linear connected portion.  
      Another embodiment of the invention is directed to a curtain airbag device that includes: a curtain airbag having a gas inlet, wherein the curtain airbag is configured to be deployed downward along an inner side surface of a vehicle cabin; a gas generator configured to supply gas from the gas inlet into the curtain airbag; and an insertion block that communicates with the gas generator. The insertion block and the gas inlet are clamped with a clamp from the outside of the gas inlet so as to be connected to each other. The gas generator or the insertion block is inserted into the gas inlet. A seal is disposed on the inner surface of the gas inlet.  
      In a further embodiment of this airbag cushion device, the seal may be composed of an elastic adhesive or rubber.  
      In another further embodiment of this airbag cushion device, the curtain airbag may be formed of two layers of sheets connected to each other at least at a periphery thereof. Further, the gas inlet may be formed by connecting the sheets along a connected portion; the seal may be disposed on at least a portion of an inner surface of the gas inlet along the connected portion.  
      In another further embodiment of this airbag cushion device, the device may also include a guide member that is configured to be vertically attached to a pillar of a vehicle and that is configured to guide the curtain airbag during the downward deployment.  
      Another embodiment of the invention addresses a curtain airbag device that includes, among other possible things: (a) a curtain airbag having a gas inlet; (b) a gas generator configured to supply gas through the gas inlet and into the curtain airbag; (c) an insertion block that communicates with the gas generator and the curtain airbag; and (d) a clamp that clamps the insertion block in the gas inlet from the outside of the gas inlet so that the insertion block and an inner surface of the gas inlet are joined. The curtain airbag is configured to be deployed downward along an inner side surface of a vehicle cabin. A seal is disposed on the inner surface of the gas inlet. The seal is of sufficient strength to maintain an internal pressure of the curtain airbag at an elevated level for at least one hour after deployment of the curtain airbag.  
      In a further embodiment of this curtain airbag device, the seal may include an elastic adhesive.  
      In another further embodiment of this curtain airbag device, the curtain airbag may be formed of two layers of sheets connected to each other at least at a periphery thereof. Further, the gas inlet may be formed by connecting the sheets along a connected portion. In addition, the seal may be disposed on at least a portion of the inner surface of the gas inlet along the connected portion.  
      In another further embodiment of this curtain airbag device, the curtain airbag device may also include a guide member that is configured to be vertically attached to a pillar of a vehicle. Further, the guide member may be configured to guide the curtain airbag during the downward deployment.  
      Another embodiment of the invention is directed to a vehicle that includes: a vehicle cabin; and a curtain airbag device that includes, a curtain airbag installed along an inner side surface of the vehicle cabin, the curtain airbag having a gas inlet; a gas generator configured to supply gas through the gas inlet and into the curtain airbag; an insertion block that communicates with the gas generator and the curtain airbag; and a clamp that clamps the insertion block in the gas inlet from the outside of the gas inlet so that the insertion block and an inner surface of the gas inlet are joined. The curtain airbag is configured to be deployed downward along an inner side surface of the vehicle cabin. A seal is disposed on the inner surface of the gas inlet. The seal is of sufficient strength to maintain an internal pressure of the curtain airbag at an elevated level for at least one hour after deployment of the curtain airbag.  
      In a further embodiment of the vehicle, the seal may include an elastic adhesive.  
      In another further embodiment of the vehicle, the curtain airbag may be formed of two layers of sheets connected to each other at least at a periphery thereof. Further, the gas inlet may be formed by connecting the sheets along a connected portion. In addition, the seal may be disposed on at least a portion of the surface of the gas inlet along the connected portion.  
      In another further embodiment of the vehicle, the curtain airbag device may also include a guide member that is configured to be vertically attached to a pillar of the vehicle cabin. Further, the guide member may be configured to guide the curtain airbag during the downward deployment.  
      The curtain airbag embodiments (and vehicles incorporating them) described herein have several advantages. For example, the intervening seal between the gas inlet and the insertion block, i.e. a gas generator or a duct communicating therewith, can prevent (or at least greatly inhibit) gas leakage from the interface between the gas inlet and the insertion block. Accordingly, when the curtain airbag is inflated, the internal pressure of the curtain airbag can be kept elevated for many hours.  
      By way of further example, the seal is disposed on the inner surface of the gas inlet so that the insertion block can easily be installed in the gas inlet.  
      By way of further example, when the seal is composed of an elastic adhesive and the gas inlet is clamped by a clamp from the outside, the seal spreads along the outer circumference of the insertion block. Accordingly, the sealing performance between the inner surface of the gas inlet and the outer circumference of the insertion block is remarkably improved.  
      By way of further example, the elastic adhesive may be non-glutinous. As a result, when the insertion block can be smoothly inserted into the gas inlet.  
      By way of further example, according to an embodiment of the present invention in which the curtain airbag is formed of two layers of sheets connected to each other at least at the periphery, the gas inlet may be formed by connecting the sheets at a linear connected portion. The seal may be disposed on portions in the inner surface of the gas inlet along the linear connected portion. The seal can sufficiently seal the air gap that is formed along the linear connected portion.  
      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. 1A  is a side view of an embodiment of curtain airbag according to the present invention;  FIG. 1B  is a cross-section view of the airbag of  FIG. 1A  taken along line B-B;  
       FIG. 2  is an enlarged view of a portion around a gas inlet of the curtain airbag of  FIGS. 1A and 1B ;  
       FIG. 3A  is a cross-sectional view taken along line III-III in  FIG. 2 ;  FIGS. 3B and 3C  are respective enlarged views around a B portion and a C portion in  FIG. 3A ;  
       FIG. 4  is an exploded perspective view around the gas inlet of de curtain airbag shown in  FIGS. 1A, 1B , and  2 ;  
       FIG. 5  is a cross-sectional view of the gas inlet taken along line V-V in  FIG. 4 ; and  
       FIG. 6  is a schematic side view illustrating a vehicle cabin provided with a curtain airbag device such as the embodiment shown in  FIGS. 1-5 . 
    
    
     DETAILED DESCRIPTION  
      Embodiments of the present invention will be described hereinafter with reference to the drawings.  FIG. 1A  is a side view illustrating a state in which the curtain airbag is inflated.  FIG. 1B  is a cross-sectional view taken along line B-B in  FIG. 1A .  FIG. 2  is an enlarged view illustrating a portion around a gas inlet.  FIG. 3A  is a cross-sectional view taken along line III-III in  FIG. 2 .  FIGS. 3B and 3C  are enlarged views around a B portion and a C portion in  FIG. 3A , respectively.  FIG. 4  is an exploded perspective view around the gas inlet.  FIG. 5  is a cross-sectional view of the gas inlet taken along line V-V in  FIG. 4 . In  FIG. 5 , the clamp shown in  FIG. 4  is not illustrated.  FIG. 6  is a schematic side view illustrating a vehicle cabin provided with a curtain airbag device.  
      As shown in  FIG. 6 , a curtain airbag  1  is disposed along a roof side  2  of a vehicle (border section between the ceiling and inner side surface of a vehicle cabin) while being folded in a slender manner in the longitudinal direction of the vehicle. A roof-side garnish (not shown) is disposed on the roof side  2 , and covers the curtain airbag  1 .  
      When a vehicle is involved in a side-on collision or a rollover, for example, the curtain airbag  1  is inflated as a result of gas being sent from an inflator  3  (gas generator). The curtain airbag  1  is deployed in the downward direction of the vehicle body along the side surface, i.e. doors and pillars, in the vehicle cabin. An upper edge of the curtain airbag  1  is provided with tabs  1   a  (shown in  FIG. 1A ) that are fastened to the roof side  2 .  
      The central portion of the upper edge of the curtain airbag  1 , with respect to the longitudinal direction, is provided with a projection that extends upward and that comprises a gas inlet  1   b . A tip portion of the inflator  3  is inserted through the gas inlet  1   b  and is clamped thereto with a clamp  3   d  such as, e.g., a band.  
      As shown in  FIG. 2 , a nozzle  3   b , which has a substantially dog-leg shape, is connected to the tip of the inflator  3  via an intervening duct  3   a  having an approximately cylindrical shape. Together the duct  3   a  and the nozzle  3   b  define an insertion block.  
      Elastic adhesives  3   e  functioning as seals are disposed on the inner surface of the gas inlet  1   b . The nozzle  3   b  and the duct  3   a  are inserted into this gas inlet  1   b , and are clamped with the clamp  3   d  such as a band from the outer circumference of the gas inlet  1   b . Accordingly, the gas inlet  1   b  and the inflator  3  are hermetically sealed and firmly combined with each other.  
      With respect to  FIG. 1B , the curtain airbag  1  in this embodiment is formed of two layers of sheets  11 . These two sheets  11  are connected to each other at, for example, the periphery, via a linear connected portion  12  (shown in  FIG. 1A ) and the like so as to form a pouched shape. The linear connected portion  12  may be, for example, in the form of stitching through the sheets  11 .  
      As shown in  FIGS. 4 and 5 , in the vicinity of the gas inlet  1   b , projections  11   t  extend upward from the upper edges of the sheets  11 . The projections  11   t  are connected to each other by the linear connected portion  12  at the upper edges and the lower edges so as to form the gas inlet  1   b . The gas inlet  1   b  is opened by separating the projections  11   t  from each other. When the gas inlet  1   b  is opened, grooves are formed along the ends of the linear connected portion  12 . As shown in  FIG. 5 , the elastic adhesives  3   e  may be disposed in and around the grooves.  
      After the nozzle  3   b  and the duct  3   a  are inserted into the gas inlet  1   b , they are clamped from the outside of the gas inlet  1   b  with the clamp  3   d . As a result, as shown in  FIGS. 3B and 3C , the sections of elastic adhesive  3   e  spread along the outer circumference of the duct  3   a . As a result, the space between the inner surface of the gas inlet  1   b  and the outer circumference of the duct  3   a  is hermetically sealed around the grooves. Accordingly, gas leakage from the space between the inner surface of the gas inlet  1   b  and the outer circumference of the duct  3   a  can be reliably prevented (or at least greatly inhibited).  
      As shown in  FIG. 6 , a C pillar  4  of the vehicle has a guide rod  5  attached thereto. The guide rod functions as a guide element for guiding the rear portion of the curtain airbag  1  along the C pillar  4  while the curtain airbag  1  is being deployed along the C pillar  4  in the downward direction of the vehicle body. The guide rod  5  has a rod-like structure that extends along the C pillar  4  in the vertical direction of the vehicle body. Both the upper and lower ends of the guide rod  5  are fixed to the C pillar  4  with, for example, bolts.  
      Furthermore, a pillar trim or garnish (not shown) covers the cabin-side of the C pillar  4 . The door-frame portion of the C pillar  4  has a weather strip (not shown) attached thereto. A lateral edge of the pillar garnish is in contact with the weather strip. The roof side  2  is provided with a roof-side garnish (not shown) that covers the curtain airbag  1 . The roof-side garnish abuts against the pillar garnish.  
      A curtain-guide member  10 , also known as a jump base, is disposed on the roof side  2  above the C pillar  4 . At the beginning of deployment of the curtain airbag  1 , the curtain-guide member  10  allows the curtain airbag  1  to pass over the top of the pillar garnish so as to guide the curtain airbag  1  towards the interior of the vehicle cabin.  
      As shown in  FIGS. 1A and 1B , the curtain airbag  1  is formed by overlapping two sheets  11 ,  11  having substantially the same shape, such that one of the sheets faces an inner side surface of the vehicle cabin and the other faces the interior of the vehicle cabin. The two sheets  11 ,  11  are connected to each other by connected portions  12 - 18  and circular connected portions  21 - 28  so as to form vertical chambers  30 - 34 , bag chambers  41 - 44 , horizontal chambers  51 ,  52 , and non-inflatable portions  61 ,  62 . Each of the connected portions  12 - 18 ,  21 - 28  may be, for example, lines of stitching.  
      A link strap  7  protrudes from a rear portion of the curtain airbag  1  in the vicinity of a bottom corner thereof. Specifically, the link strap  7  positioned below the first vertical chamber  30  of the curtain airbag  1 . Further, the link strap  7  is formed by extending the sheets  11 ,  11  in an elongated shape and joining them together by the connected portion  18 , which is later described in detail. An extremity of the link strap  7  is provided with a loop  7   a  (shown in  FIG. 6 ) that is loosely tied around the guide rod  5 . The loop  7   a  is movable vertically along the guide rod  5 . Alternatively, the extremity of the link strap  7  may be provided with a ring (not shown), the ring being set around the guide rod  5 .  
      The connected portions  12 - 18  and the circular connected portions  21 - 28  hermetically join the sheets  11 ,  11  together. For the connection between the two sheets  11 ,  11 , high-strength connecting means (such as stitching with high-strength threads, bonding with an adhesive having high adhesivity, or welding) may be used so that two sheets  11 ,  11  are unable to separate from each other even when the pressure inside the curtain airbag  1  reaches the upper limit pressure value.  
      The connected portion  12  extends substantially around the curtain airbag  1 , but at a front portion  1 F of the curtain airbag  1 , the connected portion  12  extends downward from the upper edge of the front portion  1 F so as to form a substantially U-shape. This forms the non-inflatable portion  61  along the upper edge of the front portion  1 F and the bag chamber  41  at the frontmost part of the front portion  1 F. The connected portion  12  extends along an edge of the projection  11   t  of the curtain airbag  1 , but is interrupted at the rear edge of the projection  11   t  so as to form the gas inlet  1   b  of the curtain airbag  1 .  
      The connected portion  13  is disposed slightly towards the front of the curtain airbag  1  with respect to the center of the curtain airbag  1 . The connected portion  13  is U-shaped, and its inner region forms the bag chamber  42 . The upper portion of the bag chamber  42  communicates with the gas inlet  1   b , whereas the lower portion has no openings.  
      The connected portion  13  and the peripheral connected portion  12  at the front portion  1 F of the curtain airbag  1  have the vertical chamber  31  disposed therebetween. The upper portion of the vertical chamber  31  communicates with the gas inlet  1   b , and the lower portion communicates with the bag chamber  41  and with the lower portion of the vertical chamber  32 , which will later be described in detail. To prevent the lower portion of the vertical chamber  31  from being over-inflated, the circular connected portion  21  is provided.  
      The connected portion  14  has an inverted U-shape and is disposed at the central portion of the curtain airbag  1  with respect to the longitudinal direction of the airbag  1 . The inner region of the connected portion  14  forms the bag chamber  43 . The lower portion of the bag chamber  43  communicates with the lower portions of the vertical chambers  32  and  33 , whereas the upper portion of the bag chamber  43  has no openings.  
      The connected portion  14  and the connected portion  13  have the vertical chamber  32  disposed therebetween. The upper portion of the vertical chamber  32  communicates with the gas inlet  1   b.    
      The connected portion  15  is disposed slightly towards the back of the curtain airbag  1  with respect to the center of the curtain airbag  1 . The connected portion  15  is substantially square-shaped. The upper edge and the lower edge of the connected portion  15  are respectively not in contact with the upper edge and the lower edge of the connected portion  12 . Thus, the horizontal chamber  51  is formed between the upper edge of the connected portion  12  and the upper edge of the connected portion  15 , and the horizontal chamber  52  is formed between the lower edge of the connected portion  12  and the lower edge of the connected portion  15 .  
      The connected portion  15  and the connected portion  14  have the vertical chamber  33  disposed therebetween. The upper portion of the vertical chamber  33  communicates with the front portion of the horizontal chamber  51  and with the gas inlet  1   b . The lower portion of the vertical chamber  33  communicates with the lower portion of the bag chamber  43  and the front portion of the horizontal chamber  52 .  
      The inner region of the connected portion  15  is cut off from the gas inlet hole  1   b  so as to form the non-inflatable portion  62 .  
      At the rear portion of the curtain airbag  1 , the connected portion  16  is disposed and extends generally vertically. Moreover, further towards the back of the curtain airbag  1 , the connected portion  17  having a generally L-shape is disposed.  
      The connected portions  15  and  16  have vertical chamber  34  disposed therebetween. The upper and lower portions of the vertical chamber  34  respectively communicate with the horizontal chambers  51  and  52 . The link strap  7  is positioned below the vertical chamber  34 . Moreover, slender portions extending from the sheets  11 ,  11  are combined via the linear connected portion  18  so as to form the link strap  7 .  
      The connected portions  16  and  17  have the vertical chamber  35  disposed therebetween. The upper and lower portions of the vertical chamber  35  respectively communicate with the upper and lower portions of the vertical chamber  34 . Alternatively, the vertical chamber  35  may be bag-shaped such that only the lower portion communicates with the lower portion of the vertical chamber  34 .  
      The bag chamber  44  is formed between the connected portion  17  and a part of the connected portion  12  extending along a rear portion  1 R of the curtain airbag  1 . The upper portion of the bag chamber  44  communicates with the upper portion of the vertical chamber  35 , whereas the lower portion of the bag chamber  44  has no openings. Alternatively, the lower portion of the bag chamber  44  may communicate with the lower portion of the vertical chamber  35 .  
      Both ends of each of connected portions  13 ,  14 , and  16 , are provided with circular connected portions  22 - 27  for reinforcement. An upper end of connected portion  17  is provided with a circular connected portion  28 , whereas the lower end of the connected portion  17  is connected with the connected portion  12 .  
      When a vehicle provided with such a curtain airbag device is involved in a side-on collision or a rollover, the inflator  3  generates gas so as to inflate the curtain airbag  1 . The curtain airbag  1  pushes open the roof-side garnish, and the curtain-guide member  10  allows the curtain airbag  1  to pass over the top of the pillar garnish so as to guide the curtain airbag  1  towards the interior of the vehicle cabin. Subsequently, the curtain airbag  1  begins to be deployed downward along the cabin-side of a pillar garnish.  
      The rear portion of the deploying curtain airbag  1  is guided by the guide rod  5  via the link strap  7 . The link strap  7  starts moving downward along the guide rod  5  when the curtain airbag  1  begins to be deployed. In this case, as the curtain airbag  1  is being deployed, the link strap  7  moves downward while ripping through the pillar garnish and the weather strip.  
      Furthermore, the link strap  7  moves downward along the guide rod  5  with the curtain airbag  1  until the curtain airbag  1  reaches the bottommost point of deployment. As the link strap  7  connects the curtain airbag  1  and the guide rod  5  together, the curtain airbag  1  can be deployed along the corresponding side surface of the vehicle cabin.  
      In this embodiment, the elastic adhesives  3   e , which function as seals, are disposed on the inner surface of the gas inlet  1   b . Accordingly, gas leakage from the space between the outer circumference of the duct  3   a  and the inner surface of the gas inlet  1   b  can be prevented (or at least greatly inhibited). As a result, an elevated internal pressure of the curtain airbag  1  can be maintained for several hours.  
      In this embodiment, as the elastic adhesive  3   e  must only be disposed on the grooves along the ends of the linear connected portion  12 , only a small amount of adhesive is required. More specifically, much less adhesive  3   e  is necessary as compared to a situation in which adhesive is disposed on the whole circumference of the inner surface of the gas inlet  1   b , the nozzle  3   b  and the duct  3   a . Moreover, as a result of the limited amount of adhesive necessary, the duct  3   a  can be smoothly inserted into the gas inlet  1   b.    
      In this embodiment, the elastic adhesive  3   e  may be employed as bonding agents. Therefore, when the clamp  3   d  is clamped, the elastic adhesive  3   e  may spread so as to seal air gaps sufficiently hermetically. Various commercial adhesives such as silicon-based elastic adhesives may be employed as the elastic adhesive. In addition, it is preferable that the chosen adhesive have both excellent heat resistance and excellent weather resistance.  
      The technical scope of the present invention is not limited to the embodiments described herein. Rather, modifications are permissible within the scope and spirit of the present invention. For example, the number and positions of the vertical chambers and the position of the gas inlet are not limited to those shown in the drawings. For example, the present invention is applicable to the case where the tip of the gas generator is directly inserted into the gas inlet.  
      The priority application, Japanese Application 2003-423084, which was filed Dec. 19, 2003, is incorporated herein by reference 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.