Abstract:
A curtain airbag device includes a curtain airbag disposed along an upper side surface of a vehicle facing a cabin in a folded state to be able to expand downwardly along the side surface, and an inflator for inflating the curtain airbag. A guide airbag is arranged to expand substantially at the same time when the curtain airbag is expanded. The guide airbag guides the curtain airbag toward the cabin and/or regulates an expanding direction of the curtain airbag.

Description:
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT  
       [0001]     The present invention relates to a curtain airbag for protecting a head of a vehicle occupant, and in particular, relates to a curtain airbag to be expanded along a window of a side door when a vehicle is involved in, for example, a side-on collision or rollover. Furthermore, the present invention relates to a vehicle provided with such a curtain airbag device.  
         [0002]     As an airbag for protecting a head of a vehicle occupant, a curtain airbag device is disposed around a corner of a roof and a side surface inside a vehicle cabin for expanding along a window of a side door with gas through a gas inlet. When a vehicle with the curtain airbag device is involved in, for example, a side-on collision or rollover, the curtain airbag expands downwardly along a side surface (for example, a door or a pillar) inside the vehicle cabin so as to protect a head of an occupant and prevent the occupant from being thrown out of the vehicle when a window is open.  
         [0003]     In Japanese Patent No. 3125729, a plate referred to as a jump base is provided under a folded curtain airbag for guiding the curtain airbag to expand in a certain direction, so that the curtain airbag is not caught in an upper end of a B pillar garnish.  
         [0004]     Patent Document 1: Japanese Patent No. 3125729  
         [0005]     In Japanese Patent No. 3125729, it is necessary to adjust a shape and a size of the jump base depending on a size of the vehicle body or a size and a shape of a B pillar garnish. Accordingly, it is necessary to design and produce the jump base for each type of vehicle.  
         [0006]     In view of the problems described above, an object of the present invention is to provide a curtain airbag device attachable to a vehicle regardless of a size thereof or a size and a shape of a center pillar garnish.  
         [0007]     Further objects and advantages of the invention will be apparent from the following description of the invention.  
       SUMMARY OF THE INVENTION  
       [0008]     In order to attain the objects described above, according to a first aspect of the present invention, a curtain airbag device includes a curtain airbag disposed along an upper side surface of a vehicle facing a cabin in a folded state and being capable of expanding downwardly along the side surface; an inflator for inflating the curtain airbag; and a guide airbag to be expanded substantially at the same time when the curtain airbag is expanded for guiding the curtain airbag toward the cabin and/or regulating an expanding direction of the curtain airbag.  
         [0009]     According to a second aspect of the present invention, in the curtain airbag device in the first aspect, the guide airbag is disposed between the side surface of the vehicle and the folded body of the curtain airbag.  
         [0010]     According to a third aspect of the present invention, in the curtain airbag device in the first aspect, the guide airbag is disposed under the folded curtain airbag.  
         [0011]     According to a fourth aspect of the present invention, in the curtain airbag device in one of the second and third aspects, the guide airbag expands so as to displace the curtain airbag toward the cabin over an upper end of a center pillar garnish facing the cabin.  
         [0012]     According to a fifth aspect of the present invention, in the curtain airbag device in the first aspect, the guide airbag is disposed along a side of the folded curtain airbag facing the cabin and/or along the side and a top of the folded curtain airbag.  
         [0013]     According to a sixth aspect of the present invention, in the curtain airbag device in the first aspect, the guide airbag is disposed between the side surface of the vehicle and the folded curtain airbag in an upper area of a center pillar, and is disposed along a side of the folded curtain airbag facing the cabin and/or along the side and the top of the folded curtain airbag in the upper area of a side door or a window.  
         [0014]     According to a seventh aspect of the present invention, in the curtain airbag device in the first aspect, the guide airbag is disposed between the side surface of the vehicle and the folded curtain airbag and under the folded curtain airbag in the upper area of a center pillar, and is disposed along a side of the folded curtain airbag facing the cabin and/or along the side and the top of the folded curtain airbag in the upper area of a side door or a window.  
         [0015]     According to an eighth aspect of the present invention, in the curtain airbag device in one of the sixth and seventh aspects, the guide airbag expands so as to displace the curtain airbag toward the cabin over the upper end of a center pillar garnish facing the cabin in the upper area of the center pillar.  
         [0016]     According to a ninth aspect of the present invention, in the curtain airbag device in one of the first to eighth aspects, the guide airbag has a volume smaller than that of the curtain airbag.  
         [0017]     According to a tenth aspect of the present invention, in the curtain airbag device in one of the first to ninth aspects, the inflator is connected to both the guide airbag and the curtain airbag so as to supply gas to both airbags.  
         [0018]     A vehicle according to the present invention includes the curtain airbag device according to the present invention.  
         [0019]     According to the curtain airbag and the vehicle of the present invention, the inflator starts operating upon a side-on collision or rollover of the vehicle, and the curtain airbag expands along the side surface (for example, a window opening and a center pillar) inside the vehicle cabin. The guide airbag expands substantially at the same time as the expansion of the curtain airbag so as to regulate the expanding direction of the curtain airbag or displace the curtain airbag toward the cabin, so that the center pillar garnish does not interfere with the curtain airbag. As a result, the curtain airbag expands very smoothly.  
         [0020]     When the guide airbag is disposed between the side surface of the vehicle and the folded curtain airbag, the curtain airbag moves quickly toward the cabin, and the interference of the center pillar garnish can be prevented. Also, when the guide airbag is disposed under the folded curtain airbag, the curtain airbag is pushed by the guide airbag so as to move toward the cabin, and the interference of the center pillar garnish can be prevented. In these cases, the curtain airbag is displaced toward the cabin over the upper end of the center pillar garnish facing the cabin, and the interference of the center pillar garnish with the curtain airbag can be reliably prevented.  
         [0021]     The guide airbag may be disposed along the side of the curtain airbag facing the cabin, or along the side and the top of the curtain airbag. In this case, the curtain airbag quickly expands downwardly.  
         [0022]     The guide airbag may be disposed between the side surface of the vehicle and the folded curtain airbag in the upper area of the center pillar, and may be disposed along the side of the folded curtain airbag facing the cabin and/or along the side and the top of the folded curtain airbag in the upper area of the side door or the window.  
         [0023]     When the guide airbag is disposed as described above, the curtain airbag is pushed by the guide airbag inflated adjacent to the side surface of the vehicle and moves toward the cabin in the upper area of the center pillar. Thus, the interference of the center pillar garnish can be prevented. In addition, in the upper area of the side door or the window, the curtain airbag is guided by the guide airbag inflated along the top or the side facing the cabin of the curtain airbag, and quickly expands downwardly.  
         [0024]     Furthermore, when the guide airbag extends from between the folded curtain airbag and the side surface of the vehicle to the lower portion of the folded curtain airbag in the upper area of the center pillar, the curtain airbag moves smoothly to the cabin, and the interference of the center pillar garnish can be reliably prevented.  
         [0025]     In these cases, the curtain airbag is displaced toward the cabin over the upper end of the center pillar garnish facing the cabin in the upper area of the center pillar. Thus, the interference of the center pillar garnish with the curtain airbag can be reliably prevented, and the curtain airbag expands quickly along the side surface of the vehicle.  
         [0026]     According to the present invention, the volume of the guide airbag is smaller than that of the curtain airbag. Thus, the guide airbag finishes expanding faster than the curtain airbag.  
         [0027]     According to the present invention, a common inflator preferably supplies gas to both the guide airbag and the curtain airbag, thereby reducing weight and cost of parts such as inflators and assembling. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]      FIG. 1  is a perspective view inside a vehicle including a curtain airbag device according to an embodiment of the present invention;  
         [0029]      FIG. 2  is a cross-sectional view taken along line  2 - 2  in  FIG. 1 ;  
         [0030]      FIG. 3  is a cross-sectional view taken along line  3 - 3  in  FIG. 1 ;  
         [0031]      FIG. 4  is a perspective view of a connection between airbags and an inflator;  
         [0032]      FIG. 5  is a perspective view showing a part same as that shown in  FIG. 1  when the airbags are inflated;  
         [0033]      FIG. 6  is a cross-sectional view taken along line  6 - 6  in  FIG. 5 ;  
         [0034]      FIG. 7  is a cross-sectional view taken along line  7 - 7  in  FIG. 5 ;  
         [0035]      FIG. 8  is a cross-sectional view according to another embodiment of the present invention;  
         [0036]      FIG. 9  is a cross-sectional view when airbags shown in  FIG. 8  are inflated; and  
         [0037]      FIG. 10  is a perspective view inside a vehicle including a curtain airbag device according to a further embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0038]     Hereunder, embodiments of the present invention will be described with reference to the accompanying drawings.  
         [0039]      FIG. 1  is a perspective view inside a vehicle including a curtain airbag device according to an embodiment;  FIGS. 2 and 3  are cross-sectional views taken along lines  2 - 2  and  3 - 3 , respectively, in  FIG. 1 ;  FIG. 4  is a perspective view around a connection between an inflator and airbags;  FIG. 5  is a perspective view inside the vehicle when the airbags are inflated; and  FIGS. 6 and 7  are cross-sectional views taken along lines  6 - 6  and  7 - 7  in  FIG. 5 , respectively. In the description below, front and back correspond to front and rear of a vehicle.  
         [0040]     With reference to  FIG. 1 , a vehicle including a curtain airbag device has an A pillar  2 ; a B pillar  3  serving as a center pillar; a C pillar  4 ; a roof side rail  5 ; and the like. A B pillar garnish  6  is attached to the B pillar  3 . A roof lining  7  is provided along a roof of the vehicle.  
         [0041]     As shown in FIGS.  1  to  3 , the curtain airbag device includes a curtain airbag  10  folded in a slender shape; a guide airbag  20  disposed along the folded curtain airbag  10 ; an inflator  30  for inflating the airbags  10  and  20 ; and a gas-distributing unit  40 .  
         [0042]     The curtain airbag  10  extends from an upper portion of the A pillar  2  to that of the C pillar  4  via the roof side rail  5 . A plurality of tabs  11  protrudes upwardly from an upper hem of the curtain airbag  10  with a predetermined spacing therebetween. The tabs  11  are fixed to the roof side rail  5  by fastenings  8  such as bolts and rivets. A gas inlet  12  extends from a rear portion of the curtain airbag  10 , and is connected to a first gas outlet  41  of the gas-distributing unit  40 . A size of the inflated curtain airbag  10  is large enough to cover substantially an entire window opening of a side door ranging from the vicinity of the A pillar  2  to the vicinity of the C pillar  4 .  
         [0043]     As shown in  FIG. 3 , the folded curtain airbag  10  is disposed above the B pillar garnish  6 . When the folded curtain airbag  10  is projected downwardly, at least a part of the folded curtain airbag  10  is disposed closer to the B pillar  3  than an end  6   a  of the B pillar garnish  6  facing the cabin.  
         [0044]     The guide airbag  20  extends from a front end to a rear end of the curtain airbag  10 . The guide airbag  20  expands only along the vicinity of the upper hem of the inflated curtain airbag  10 , and a volume thereof is smaller than that of the curtain airbag  10 .  
         [0045]     A plurality of tabs  21  protrudes from the upper hem of the guide airbag  20  with a predetermined spacing therebetween so as to overlap the tabs  11  of the curtain airbag  10 . The tabs  21  are fixed to the roof side rail  5  by the fastenings  8  together with the tabs  11 .  
         [0046]     A gas inlet  22  extends toward a rear side from a rear portion of the guide airbag  20 , and is connected to a second gas outlet  42  of the gas-distributing unit  40 .  
         [0047]     The guide airbag  20  is folded so as to form a slender strip, disposed along the folded curtain airbag  10 , and integrated with the folded curtain airbag  10  by binding tools such as tapes (not shown). The binding tools can easily be torn when the airbags  10  and  20  are inflated.  
         [0048]     As shown in  FIG. 2 , the front and rear portions of the strip-shaped guide airbag  20  are disposed so as to cover a top and a side of the folded curtain airbag  10  facing the cabin. As shown in  FIG. 3 , a portion of the folded guide airbag  20  substantially in the middle position in a front-back direction of the vehicle body is disposed between the folded curtain airbag  10  and the roof side rail  5 . The middle position in the front-back direction of the vehicle body substantially corresponds to the upper area of the B pillar  3 .  
         [0049]     As shown in  FIGS. 2 and 3 , the folded airbags  10  and  20  are covered with the roof lining  7 .  
         [0050]     The gas-distributing unit  40  includes the gas outlets  41  and  42  at the front side, and a gas outlet  43  at the rear side. The gas outlet  43  is connected to the inflator  30  via an adaptor  31 . The gas inlet  12  of the curtain airbag  10  and the gas inlet  22  of the guide airbag  20  are fitted onto the gas outlets  41  and  42 , respectively, and tied by bands  45  and  46 . The gas-distributing unit  40  and the inflator  30  are fixed to the C pillar  4 .  
         [0051]     An operation of the curtain airbag device  1  having the above-described structure will be described next. When the vehicle is involved in, for example, a side-on collision or rollover, the inflator  30  blows gas out so as to supply the gas to the airbags  10  and  20 , and the airbags  10  and  20  start expanding. Since the guide airbag  20  is smaller than the curtain airbag  10 , the guide airbag  20  finishes expanding faster than the curtain airbag  10 , and changes the position or regulates the expanding direction of the curtain airbag  10 . In the upper areas of the front door and the rear door, the guide airbag  20  is inflated between the curtain airbag  10  and the roof lining  7 . As a result, the roof lining  7  is pushed open, and the curtain airbag  10  expands downwardly with the guide airbag  20 .  
         [0052]     In the upper area of the B pillar  3 , the guide airbag  20  expands between the curtain airbag  10  and the roof side rail  5  so as to push the roof lining  7  open and displace the curtain airbag  10  toward the cabin over the upper area of the end  6   a  of the B pillar garnish  6  facing the cabin. As a result, as shown in  FIG. 7 , the curtain airbag  10  expands downwardly along the B pillar garnish  6  without interference of the B pillar garnish  6 . In this manner, the entire curtain airbag  10  expands downwardly smoothly. In the upper area of the B pillar garnish  6 , the guide airbag  20  may have a structure that expands both under the curtain airbag  10  and adjacent to the roof side rail  5 . In this embodiment, the airbags  10  and  20  are inflated by a common inflator  30 , thereby reducing cost and weight.  
         [0053]     Another embodiment will be described with reference to  FIGS. 8 and 9 . In this embodiment, a guide airbag  20 A is disposed only above the B pillar garnish  6 . A tab  21 A of the guide airbag  20 A extends between the folded curtain airbag  10  and the roof side rail  5 . A gas inlet of the guide airbag  20 A extends toward the rear side and is connected to the gas-distributing unit  40  (not shown in  FIGS. 8 and 9 ). Structures other than these components are the same as in the above-described embodiment.  
         [0054]     In this embodiment, when the inflator starts operating, the guide airbag  20 A finishes expanding faster than the curtain airbag  10 . In the upper area of the B pillar garnish  6 , the guide airbag  20 A expands under the curtain airbag  10 . Therefore, the curtain airbag  10  is pushed by the guide airbag  20 A so as to move toward the cabin over the end  6   a  of the B pillar garnish  6  facing the cabin, and thus expands downwardly smoothly without the interference of the B pillar garnish  6 .  
         [0055]     In the embodiment shown in  FIGS. 8 and 9 , the guide airbag  20 A is disposed only above the B pillar garnish  6 . The guide airbag may be disposed so as to cover the top and the side facing the cabin of the curtain airbag  10  in the upper areas of the front door and the rear door as shown in  FIG. 1 .  
         [0056]     In the embodiment shown in  FIGS. 8 and 9 , the guide airbag  20 A expands under the curtain airbag  10 . The guide airbag may expand adjacent to the roof side rail  5 , or expand both under the curtain airbag and adjacent to the roof side rail  5 .  
         [0057]     In the above-described embodiments, the curtain airbag  10  is displaced toward the cabin over the B pillar garnish  6  in the upper area of the B pillar garnish  6 . To do so, a diameter d of the inflated guide airbag  20  or  20 A above the B pillar garnish  6  is desirably larger than a width W 1  of the B pillar garnish  6  in the left-right direction of the vehicle body. When the diameter d is larger than a width W 2  defined by projecting the width W 1  in a direction perpendicular to the side surface of the roof side rail  5  facing the cabin, the interference between the curtain airbag  10  and the B pillar garnish  6  is reliably prevented.  
         [0058]     A conventional jump base is not required in any of the above-described embodiments, and the common curtain airbag device can be attached to a vehicle regardless of a size thereof or a size and a shape of the B pillar garnish.  
         [0059]      FIG. 10  is a perspective view inside a vehicle including a curtain airbag device  1 A according to a further embodiment. In the curtain airbag device  1 A, the folded curtain airbag  10  extends from the upper portion of the A pillar  2  to that of the C pillar  4  along the roof side rail  5 . In addition, the guide airbag  20  folded so as to form a strip shape extends from the front end to the rear end of the folded curtain airbag  10 . In this embodiment, the plurality of tabs  11  and  21  protrudes from the upper hems of the curtain airbag  10  and the guide airbag  20 , respectively, with a spacing therebetween in the front-back direction of the vehicle body. The tabs  11  and  21  are fixed together to the roof side rail  5  by the fastenings  8  such as bolts and rivets.  
         [0060]     In this embodiment, the tabs  11  and  21  are not provided at the upper hems of the curtain airbag  10  and the guide airbag  20  substantially in the middle position in the front-back direction of the vehicle body. Thus, the curtain airbag  10  and the guide airbag  20  are not connected to the roof side rail  5  substantially in the middle position in the front-back direction of the vehicle body. The middle position in the front-back direction of the vehicle body substantially corresponds to the upper area of the B pillar  3 .  
         [0061]     In this embodiment, the front and rear portions of the guide airbag  20  are disposed so as to cover the top and the side facing the cabin of the folded curtain airbag  10 , and the portion in the upper area of the B pillar  3  is disposed between the folded curtain airbag  10  and the roof side rail  5 .  
         [0062]     The guide airbag  20  may be disposed under the folded curtain airbag  10 . Moreover, the guide airbag  20  may be disposed between the folded curtain airbag  10  and the roof side rail  5 , and under the folded curtain airbag  10 .  
         [0063]     Structures other than the curtain airbag device  1 A are the same as in the above-described curtain airbag device  1  shown in FIGS.  1  to  7 , and components having the same reference numerals or symbols correspond to the same components.  
         [0064]     When the curtain airbag device  1 A having the above-described structure is shipped from a manufacturing facility, the folded guide airbag  20  and the folded curtain airbag  10  are integrated together by the binding tools such as tapes in advance. First, the folded guide airbag  20  is disposed so as to cover the top and the side facing the cabin over the entire length, when the folded curtain airbag  10  is attached to the vehicle body. The front ends and the rear ends of both airbags are integrated together by the binding tools such as tapes. Next, the middle portion of the guide airbag  20  is twisted so as to be disposed along a side adjacent to the roof side rail, when the folded curtain airbag  10  is attached to the vehicle body. The middle portions of both airbags are integrated together by the binding tools such as tapes.  
         [0065]     When the integrated structure of the folded guide airbag  20  and the folded curtain airbag  10  are attached to the vehicle body, the integrated structure is disposed along the roof side rail  5 , and the front and rear ends thereof are fixed to the roof side rail  5  by the fastenings  8  via the tabs  11  and  21 .  
         [0066]     In this manner, according to this embodiment, the curtain airbag  10  and the guide airbag  20  can be easily attached to the roof side rail  5  only by fixing the front ends and the rear ends of both airbags.  
         [0067]     According, to the curtain airbag device  1 A, the middle portions of the curtain airbag  10  and the guide airbag  20  in the front-back direction of the vehicle body are not connected to the roof side rail  5 . Therefore, the middle portion of the guide airbag  20  in the front-back direction of the vehicle body may be tucked between the folded curtain airbag  10  and the roof side rail  5  after fixing the front ends and the rear ends of the curtain airbag  10  and the guide airbag  20 .  
         [0068]     According to the curtain airbag device  1 A, the curtain airbag  10  is not connected to the roof side rail  5  in the upper area of the B pillar  3 . Accordingly, when the guide airbag  20  is inflated between the curtain airbag  10  and the roof side rail  5 , the curtain airbag  10  is pushed by the guide airbag  20  and moves smoothly and quickly toward the cabin. As a result, the interference of the B pillar garnish  6  with the curtain airbag  10  is reliably prevented.  
         [0069]     The above-described embodiments are merely examples for carrying out the present invention, and embodiments other than those shown in the drawings are permissible within the scope of the present invention. For example, the curtain airbag and the guide airbag may be inflated by separate inflators. Moreover, the inflator may be disposed at a predetermined position of the roof side rail or on the A pillar.  
         [0070]     In the present invention, the center pillar refers to a pillar disposed between a front pillar at the forefront in the front-back direction of the vehicle body and a rear pillar at the rearmost position. In the above-described embodiments, the vehicle body includes three pillars, the A pillar, the B pillar, and the C pillar, from the front to the rear, and only the B pillar corresponds to the center pillar. When a vehicle body includes four pillars, an A pillar, a B pillar, a C pillar, and a D pillar, the B pillar and the C pillar correspond to the center pillars.  
         [0071]     The disclosure of Japanese Patent Application No. 2004-273613, filed on Sep. 21, 2004, is incorporated in the application.  
         [0072]     While the invention has been explained with reference to the specific embodiments of the invention, the explanation is illustrative and the invention is limited only by the appended claims.