Patent Publication Number: US-2023150599-A1

Title: Saddle riding-type vehicle

Description:
TECHNICAL FIELD 
     The present invention relates to a saddle riding-type vehicle. 
     BACKGROUND ART 
     Conventionally, a saddle riding-type vehicle including an airbag module has been known (see, for example, Patent Literature 1). In Patent Literature 1, the airbag module is supported by a main frame extending rearward and downward from a head pipe via a stay, and is disposed behind the head pipe. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: JP 6454364 B2 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     When an inflator is disposed on a side of the head pipe and the airbag module is disposed closer to the head pipe, the airbag module can be compactly disposed in a front-rear direction. However, since the inflator is disposed on the side of the head pipe, the airbag may be deployed in such a way as to be inclined in a left-right direction. 
     The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a saddle riding-type vehicle capable of deploying an airbag while suppressing the airbag from being inclined in the left-right direction. 
     Solution to Problem 
     A saddle riding-type vehicle includes: a retainer ( 41 ) that is provided behind a head pipe ( 15 ); an inflator ( 43 ); and an airbag ( 42 ) that is housed in the retainer ( 41 ), inflates by gas (G) discharged by the inflator ( 43 ), and is deployed in front of an occupant, in which the airbag ( 42 ) includes a proximal end portion ( 121 ) that is positioned in the retainer ( 41 ) when the airbag ( 42 ) is deployed and an outward deployment portion ( 122 ) that extends from the proximal end portion ( 121 ) and is deployed to an outside of the retainer ( 41 ) when the airbag ( 42 ) is deployed, a tab ( 161 ) is provided on the proximal end portion ( 121 ), and the tab ( 161 ) is fixed to the retainer ( 41 ). 
     In the above configuration, an opening ( 66   a ) into which the tab ( 161 ) is inserted may be formed in a side surface ( 66 ) of the retainer ( 41 ), and the tab ( 161 ) may be fixed to an outer side of the retainer ( 41 ) through the opening ( 66   a ). 
     In the above configuration, the proximal end portion ( 121 ) may include a bag left-right extending portion ( 121 A) connected to the inflator ( 43 ) and a bag upward extending portion ( 121 B) extending upward from the bag left-right extending portion ( 121 A), and the tab ( 161 ) may be provided on a side opposite from the inflator ( 43 ) in a longitudinal direction (X 1 ) of the bag left-right extending portion ( 121 A). 
     In the above configuration, the tab ( 161 ) may be provided below a line (L 2 ) passing through a center of the inflator ( 43 ) and extending along the bag left-right extending portion ( 121 A) in a front view. 
     In the above configuration, a loop diffuser ( 141 ) that guides the gas (G) may be provided in the inflator ( 43 ), and the loop diffuser ( 141 ) may be disposed in a gas flow path of the proximal end portion ( 121 ). 
     Advantageous Effects of Invention 
     A saddle riding-type vehicle includes: a retainer that is provided behind a head pipe; an inflator; and an airbag that is housed in the retainer, inflates by gas discharged by the inflator, and is deployed in front of an occupant, in which when the airbag is deployed, the airbag includes a proximal end portion that is positioned in the retainer and an outward deployment portion that extends from the proximal end portion and is deployed to the outside of the retainer, a tab is provided on the proximal end portion, and the tab is fixed to the retainer. With this configuration, it is possible to deploy the airbag while suppressing the airbag from being inclined in the left-right direction. 
     In the above configuration, an opening into which the tab is inserted may be formed in a side surface of the retainer, and the tab may be fixed to an outer side of the retainer through the opening. With this configuration, the fixing portion of the tab can be made hardly affected by the gas injected from the inflator. 
     In the above configuration, the proximal end portion may include a bag left-right extending portion connected to the inflator and a bag upward extending portion extending upward from the bag left-right extending portion, and the tab may be provided on a side opposite from the inflator in a longitudinal direction of the bag left-right extending portion. With this configuration, it is possible to fix a portion of the airbag that is hardly affected by the gas injected from the inflator, and it is possible to suppress the airbag from being inclined to in the left-right direction. 
     In the above configuration, the tab may be provided below a line passing through a center of the inflator and extending along the bag left-right extending portion in the front view. With this configuration, since the fixing tab is positioned below a line passing through the center of the inflator, the airbag can be fixed at a base side together with a connecting portion with the inflator, and it is possible to deploy the airbag deployed while suppressing the airbag from being inclined in the left-right direction. 
     In the above configuration, a loop diffuser that guides the gas may be provided in the inflator, and the loop diffuser may be disposed in a gas flow path of the proximal end portion. With this configuration, it is possible to reinforce the proximal end portion, and it is possible to deploy the airbag while stabilizing the posture of the proximal end portion. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a left side view of a motorcycle according to an embodiment of the present invention. 
         FIG.  2    is a right side view of a vehicle body frame. 
         FIG.  3    is a view of a front portion of the motorcycle as viewed from above on an occupant side. 
         FIG.  4    is a view of an airbag unit attached to the vehicle body frame as viewed from a rear side. 
         FIG.  5    is a right side view of the airbag unit attached to the vehicle body frame. 
         FIG.  6    is a right side view of the airbag unit in a state in which an exterior member is removed. 
         FIG.  7    is a left side view of the airbag unit in a state in which the exterior member is removed. 
         FIG.  8    is an exploded perspective view of the airbag unit. 
         FIG.  9    is an enlarged view of a front case illustrated in  FIG.  8   . 
         FIG.  10    is a view of the deployed and inflating airbag as viewed from the rear side (corresponding to the occupant side). 
         FIG.  11    is a view of the deployed and inflating airbag as viewed from a front side (a side opposite from an occupant). 
         FIG.  12    is an explanatory view of panels forming a circumferential length difference. 
         FIG.  13    is a front view of a loop diffuser. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     An embodiment of the present invention will be described below with reference to the drawings. Note that, in the description, directions such as a front-rear direction, a left-right direction, and a vertical direction are the same as directions with respect to a vehicle body unless otherwise specified. In the drawings, Reference Sign FR denotes the front side of the vehicle body, Reference Sign UP denotes the upper side of the vehicle body, and Reference Sign LH denotes the left side of the vehicle body. 
       FIG.  1    is a left side view of a motorcycle  1  according to the embodiment of the present invention. 
     The motorcycle  1  is a scooter type saddle riding-type vehicle including a vehicle body frame  10 , a steering system  11  that steerably supports a front wheel  2 , a power unit  12  supported by a rear portion of the vehicle body frame  10 , a rear wheel  3 , and a seat  13  on which an occupant sits astride the seat. 
     Further, the motorcycle  1  includes a vehicle body cover  14  that covers a vehicle body such as the vehicle body frame  10 . 
       FIG.  2    is a right side view of the vehicle body frame  10 . 
     Referring to  FIGS.  1  and  2   , the vehicle body frame  10  includes a head pipe  15  provided at a front end portion of the vehicle body frame  10 , a down frame  16  extending rearward and downward from a rear side of the head pipe  15 , a pair of left and right lower frames  17  extending rearward from a lower end portion of the down frame  16 , and a pair of left and right seat frames  18  extending rearward and upward from rear end portions of the lower frames  17 . 
     The head pipe  15  and the down frame  16  are positioned at the center of a vehicle width similarly to the front wheel  2 . 
     The power unit  12  is a unit swing engine including an engine as a drive source of the rear wheel  3  and a swingarm supporting the rear wheel  3  in a swingable manner, the engine and the swingarm being integrated with each other. The power unit  12  is supported by the vehicle body frame  10  in a swingable manner via a link mechanism (not illustrated) provided at a front portion of the power unit  12 . 
     A rear suspension  20  is stretched between a rear portion of the seat frame  18  and a rear end portion of the power unit  12 . 
     A storage box (not illustrated) supported by the seat frame  18  is disposed below the seat  13 . The seat  13  is supported by the seat frame  18  via the storage box. 
     A pair of left and right step floors  21  having a plate shape and on which feet of the occupant sat on the seat  13  are placed are provided in front of and below the seat  13 , and cover the lower frame  17  from above. 
     The steering system  11  includes a pair of front forks  11   a  disposed on the left and right sides of the front wheel  2 , a bridge member  11   b  connecting upper end portions of the left and right front forks  11   a  in a vehicle width direction, a steering shaft  11   c  extending upward from the center of the bridge member  11   b  and rotatably supported by the head pipe  15 , a handlebar post  11   d  fixed to an upper end portion of the steering shaft  11   c , and a steering handlebar  11   e  fixed to an upper end of the handlebar post  11   d.    
     An axis  15   a  of the head pipe  15  is inclined rearward with respect to a vertical direction in a vehicle side view. An axis of rotation of the steering shaft  11   c  coincides with the axis  15   a . The handlebar post  11   d  obliquely extends rearwards and upwards from the head pipe  15  side along the axis  15   a.    
     The front wheel  2  is supported by an axle  2   a  connecting lower end portions of the front forks  11   a  in a left-right direction. 
     A front fender  22  that covers the front wheel  2  from above is fixed to the front forks  11   a.    
       FIG.  3    is a view of a front portion of the motorcycle  1  as viewed from above on an occupant side. 
     Referring to  FIGS.  1  and  3   , the vehicle body cover  14  includes a front cover  23  that covers the steering system  11  and the head pipe  15  from the front side, an inner cover  24  that covers the steering system  11  and the head pipe  15  from the rear side, a lower cover  25  that covers the lower frame  17  from the outer side below the step floors  21 , and a side cover  26  that covers the seat frame  18  from the outer side below the seat  13 . 
     In the vehicle side view, a straddling space  27  recessed downward when viewed from the side of the vehicle is defined between the inner cover  24  and a front end portion of the seat  13 . When getting on and off the motorcycle  1 , the occupant can straddle the motorcycle  1  through the straddling space  27 . 
     Referring to  FIGS.  1  and  3   , the motorcycle  1  includes an airbag device  30  that reduces an impact on the occupant. 
     The airbag device  30  includes an airbag unit  31 , an acceleration sensor (not illustrated) that detects an impact on the motorcycle  1 , and an airbag control device (not illustrated) that controls the operation of the airbag unit  31  based on a detection result of the acceleration sensor. 
     The airbag unit  31  is disposed on the rear side of the inner cover  24  and is positioned in front of the occupant sat on the seat  13 . The airbag unit  31  is provided behind the head pipe  15  and below the handlebar  11   e , and is positioned at a front side of the straddling space  27 . 
     A rear portion of the airbag unit  31  is exposed from a notch portion provided in a central portion of the inner cover  24  to the straddling space  27  positioned on the outside of the vehicle body cover  14 . 
       FIG.  4    is a view of the airbag unit  31  attached to the vehicle body frame  10  as viewed from the rear side.  FIG.  5    is a right side view of the airbag unit  31  attached to the vehicle body frame  10 .  FIG.  6    is a right side view of the airbag unit  31  in a state in which an exterior member  40  is removed.  FIG.  7    is a left side view of the airbag unit  31  in a state in which the exterior member  40  is removed. 
     The airbag unit  31  is disposed behind the head pipe  15  and the handlebar post  11   d , and is disposed in such a way as to be inclined rearward along the rear side of the head pipe  15  in the vehicle side view. 
     The airbag unit  31  is fixed to a stay  32  (see  FIG.  2   ) provided at the front end portion of the vehicle body frame  10 . 
     Referring to  FIGS.  2  and  5   , the stay  32  includes a first stay  33  provided at an upper portion of the head pipe  15  and a second stay  34  provided at an upper portion of the down frame  16 . 
     The first stay  33  is provided above a connecting portion  16   a  between the head pipe  15  and an upper end of the down frame  16 . 
     The second stay  34  is disposed below the first stay  33 . 
       FIG.  8    is an exploded perspective view of the airbag unit  31 . 
     The airbag unit  31  includes a box-shaped retainer  41  provided in front of the occupant sat on the seat  13  (see  FIG.  1   ), an airbag  42  housed in the retainer  41 , an inflator  43  that discharges gas into the airbag  42 , a fixing member  44  that fixes the inflator  43  and the airbag  42  to the retainer  41 , and the exterior member  40  that covers the retainer  41  from the outer side. 
     The retainer  41  of the present embodiment is formed in a box shape by assembling a plurality of parts. The retainer  41  is configured by assembling an inflator accommodating portion  51  covering the inflator  43  from the front side, a retainer front half  52  provided behind the head pipe  15 , and a retainer rear half  53  provided on the occupant side and joining with the retainer front half  52  and the inflator accommodating portion  51  from the rear side. 
     The inflator accommodating portion  51  and the retainer front half  52  are coupled and integrated by welding, for example. The inflator accommodating portion  51  and the retainer front half  52  are coupled to form a front case  55  constituting substantially a front half of the retainer  41 . 
     The retainer rear half  53  is a rear case constituting substantially a rear half of the retainer  41 . 
     The retainer  41  is formed by coupling the retainer rear half  53  to the front case  55  from the rear side. 
     In  FIGS.  4  and  8   , the retainer  41  is a box-shaped member formed in an inverted L shape when viewed from the occupant side (the rear side of the vehicle). Note that, in the following description, an L shape means an L shape when the retainer  41  is viewed from the front side or the rear side. The retainer  41  has an inverted L shape when viewed from the rear side, but it can be said that the retainer  41  is formed in an L shape. 
     The retainer  41  is fixed to the front end portion of the vehicle body frame  10  via the stay  32  (see  FIG.  2   ), and is positioned behind the head pipe  15  and the down frame  16 . 
     Referring to  FIGS.  4  to  7   , the retainer  41  includes a vertically extending portion  45  (see  FIG.  7   ) extending vertically, and a side extending portion  46  (see  FIG.  7   ) extending outward in the vehicle width direction from a lower side of the vertically extending portion  45 . 
     The vertically extending portion  45  is a box-shaped portion extending in the vertical direction along the head pipe  15 , and is inclined rearward in the vehicle side view. The vertically extending portion  45  is positioned at the center of the vehicle width and overlaps with upper end portions of the handlebar post  11   d , the head pipe  15 , and the down frame  16  from the rear side. 
     The side extending portion  46  is a box-shaped portion extending in the vehicle width direction. The side extending portion  46  passes through the outer side of the head pipe  15  from the side portion of the vertically extending portion  45  and extends outward in the vehicle width direction and forward. 
     The retainer  41  is formed in an L shape in which the side extending portion  46  extends from the vertically extending portion  45 . An L-shaped airbag passage  47  (see  FIG.  7   ) formed by an internal space of the vertically extending portion  45  and an internal space of the side extending portion  46  is formed inside the retainer  41 . 
     An opening  48  (see  FIGS.  6  to  8   ) for exposing the airbag passage  47  upward is formed at an upper portion of the vertically extending portion  45 . The airbag  42  is deployed upward from the opening  48 . 
     The inflator  43  is disposed in the side extending portion  46  and is disposed offset outward in the vehicle width direction with respect to the head pipe  15  positioned at the center of the vehicle width. 
       FIG.  9    is an enlarged view of the front case  55  illustrated in  FIG.  8   . 
     Parts of the retainer front half  52  of the retainer  41 , the inflator accommodating portion  51 , and the retainer rear half  53  of the retainer  41  will be described. 
     As illustrated in  FIGS.  8  and  9   , the retainer front half  52  includes a substantially rectangular front wall portion  65  that is vertically long. The front wall portion  65  constitutes a front side surface of the vertically extending portion  45 . A lower wall portion  68  extending rearward is formed at a lower edge of the front wall portion  65 . A first side wall (side surface)  66  extending rearward is formed at an edge of one of the left and right sides of the front wall portion  65 . A second side wall  67  extending rearward is formed at an upper portion of an edge of the other one of the left and right sides of the front wall portion  65 . 
     An extending wall portion  69  extending toward the side extending portion  46  and the front side of the vehicle is formed at a lower portion of the edge of the other one of the left and right sides of the front wall portion  65 . The extending wall portion  69  is continuous with a lower portion of the front wall portion  65 . An extending portion upper wall  70   a  extending outward in the vehicle width direction and rearward is formed at an upper edge of the extending wall portion  69 . The extending portion upper wall  70   a  is continuous with a lower end of the second side wall  67 . An extending portion lower wall  70   b  extending outward in the vehicle width direction and rearward is formed at a lower edge of the extending wall portion  69 . The extending portion lower wall  70   b  is continuous with a side portion of the lower wall portion  68 . 
     A recess  71  formed by denting the retainer front half  52  rearward is formed at a lower end portion of the retainer front half  52 . The recess  71  is a portion where a lower end portion of the front wall portion  65  and a front portion of the lower wall portion  68  are recessed toward the inside of the retainer  41 . The recess  71  is provided at a central portion of the front wall portion  65  in a width direction. A rear portion of an upper end portion of the down frame  16  is positioned in the recess  71 . Therefore, a lower end portion of the retainer  41  can be disposed close to the down frame  16 , and the retainer  41  can be disposed compactly. 
     A rib-shaped step portion  72  protruding toward the inside of the retainer  41  is provided on an inner surface of the extending wall portion  69 . The step portion  72  is formed to be longer in the left-right direction than in the vertical direction and extends in the left-right direction in the retainer  41 . A plurality of step portions  72  are arranged side by side in the vertical direction. The step portion  72  is formed by pushing out a portion of the extending wall portion  69  from the outside to the inside of the retainer  41 . 
     As illustrated in  FIG.  5   , a fastening portion  73  for fastening the retainer  41  to the stay  32  of the vehicle body frame  10  is provided at a front surface of the front wall portion  65  of the retainer front half  52 . The fastening portion  73  includes a first fastening member  74  fastened to the first stay  33  of the head pipe  15  and a second fastening member  75  fastened to the second stay  34  of the down frame  16 . The first fastening member  74  is fastened to the first stay  33  by a fixing tool (not illustrated). The second fastening member  75  is fastened to the second stay  34  by a pair of left and right fixing tools  97  (see  FIGS.  5  and  6   ). 
     As illustrated in  FIGS.  6  and  9   , a first fixing piece  56   a  and a second fixing piece  57   a  extending outward in the vehicle width direction from the first side wall  66  are provided on the first side wall  66  of the retainer front half  52 . A slit hole (opening portion)  66   a  penetrating in a thickness direction and extending in the vertical direction is formed in the first side wall  66 . The slit hole  66   a  is formed on the rear side of the second fixing piece  57   a . The slit hole  66   a  allows the airbag passage  47  to communicate with the inside and the outside of the retainer  41 . 
     As illustrated in  FIGS.  8  and  9   , the inflator accommodating portion  51  is connected to the retainer front half  52 . The inflator accommodating portion  51  is a box-shaped part whose rear portion is opened rearward. The inflator accommodating portion  51  includes a substantially rectangular wall portion  78  covering the inflator  43  from the front side. An upper wall portion  79  extending rearward is formed at an upper edge of the wall portion  78 . A lower wall portion  80  extending rearward is formed at a lower edge of the wall portion  78 . An outer side wall portion  81  extending rearward is formed at an outer side edge of the wall portion  78  in the vehicle width direction. An inner side wall portion  82  extending rearward is formed on an inner side edge of the wall portion  78  in the vehicle width direction. 
     The upper wall portion  79  overlaps with the extending portion upper wall  70   a  of the retainer front half  52  from above, the lower wall portion  80  overlaps with the extending portion lower wall  70   b  of the retainer front half  52  from below, and the inner side wall portion  82  overlaps with the extending wall portion  69  of the retainer front half  52  from the inner side in the vehicle width direction. 
     The inflator accommodating portion  51  is welded to the retainer front half  52  by a welded fixing portion  51   b  (fixing portion) which is a portion where the upper wall portion  79 , the lower wall portion  80 , and the inner side wall portion  82  overlap with the retainer front half  52  from the outer side. 
     A main body accommodating portion  78   a  (see  FIG.  7   ) formed by making a central portion of the wall portion  78  bulge forward is formed in the wall portion  78  of the inflator accommodating portion  51 . A receiving surface portion  78   b  for receiving the inflator  43  is formed around the main body accommodating portion  78   a . A plurality of fixing hole portions (not illustrated) penetrating in the thickness direction are formed in the receiving surface portion  78   b.    
     A tubular inflator main body  43   a  of the inflator  43  that ejects gas is accommodated in the main body accommodating portion  78   a . In the inflator  43 , a flange portion  43   b  extending in a radial direction from an outer circumference of a rear portion of the inflator main body  43   a  abuts on the receiving surface portion  78   b . The flange portion  43   b  is sandwiched between the receiving surface portion  78   b  and the frame-shaped fixing member  44 . The inflator  43  is fastened to an inner surface of the wall portion  78  by a fixing tool  83  (see  FIG.  6   ) inserted into the fixing hole portions (not illustrated) of the fixing member  44 , the flange portion  43   b , and the receiving surface portion  78   b . The wall portion  78  is an inflator support portion that supports the inflator  43 . 
     The inflator  43  is disposed on the inner surface of the wall portion  78  in a direction in which an axis  43   c  of the tubular inflator main body  43   a  is directed in the front-rear direction of the vehicle in the vehicle side view. The wall portion  78  to which the flange portion  43   b  is fixed is slightly inclined rearward with respect to the vertical direction in the vehicle side view. Therefore, the axis  43   c  extends rearward and downward in the vehicle side view. Here, the inclination of the axis  43   c  in the vehicle side view is smaller than 45° with respect to the horizontal. Further, the inflator  43  is disposed in a direction in which the axis  43   c  becomes closer to the center of the vehicle width toward the rear side of the vehicle in plan view viewed from above. 
     The inflator  43  ejects gas from a plurality of gas ejection ports  43   d  (see  FIG.  8   ) provided in the outer circumference of the inflator main body  43   a  behind the flange portion  43   b . The frame-shaped fixing member  44  surrounds the gas ejection ports  43   d . The gas ejected from the gas ejection ports  43   d  is guided by an inner surface of the fixing member  44  to flow rearward. 
     A wire passage hole  79   a  is provided in the lower wall portion  80  of the inflator accommodating portion  51 . A wire  49  (see  FIG.  7   ) connecting the inflator  43  to the airbag control device passes through the wire passage hole  79   a.    
     As illustrated in  FIG.  8   , the retainer rear half  53  includes a substantially rectangular rear wall portion  85  that is a vertically long plate. The rear wall portion  85  constitutes a rear side surface of the vertically extending portion  45 . A side rear wall portion  86  extending outward in the vehicle width direction is formed at a lower-left portion of the rear wall portion  85 . The side rear wall portion  86  constitutes a rear side surface of the side extending portion  46 . An extending portion side wall  87  extending forward and outward in the vehicle width direction is formed at an edge portion of the outer side of the side rear wall portion  86  in the vehicle width direction. 
     A first side wall  88  extending forward from a side edge of a side opposite from the side extending portion  46  is formed at a side edge of one of the left and right sides of the rear wall portion  85 . The second side wall  89  extending forward from a side edge of a side adjacent to the side extending portion  46  is formed at a side edge of the other one of the left and right sides of the rear wall portion  85 . The second side wall  89  is formed at an upper portion of the rear wall portion  85 . 
     Furthermore, the retainer rear half  53  includes a lower wall portion  90  (see  FIG.  7   ) extending forward from a lower edge of the rear wall portion  85 , a lower edge of the side rear wall portion  86 , and a lower edge of the extending portion side wall  87 , and an extending portion upper wall  91  extending forward from an upper edge of the side rear wall portion  86  and an upper edge of the extending portion side wall  87 . The extending portion upper wall  91  is continuous with a lower end of the second side wall  89 . 
     The side rear wall portion  86  of the retainer rear half  53  faces a rear surface  43   e  of the inflator main body  43   a . The axis  43   c  of the inflator main body  43   a  intersects the side rear wall portion  86  of the retainer  41 . 
     A stepped shape  93  protruding toward the inside of the retainer  41  is provided on an inner surface of the side rear wall portion  86 . The stepped shape  93  is formed in a rib shape longer in the left-right direction than in the vertical direction, and extends in the left-right direction in the retainer  41 . 
     A plurality of stepped shapes  93  are arranged side by side in the vertical direction. The plurality of stepped shapes  93  arranged side by side in the vertical direction guide a flow of the gas ejected from the inflator  43  in the vehicle width direction. 
     The stepped shape  93  is formed by pushing out a portion of the side rear wall portion  86  from the outside to the inside of the retainer  41 . 
     A first fixing piece  56   b  and a second fixing piece  57   b  extending outward in the vehicle width direction from the first side wall  88  are provided on the first side wall  88  of the retainer rear half  53 . 
     A notch portion  88   a  (see  FIG.  6   ) formed by cutting out the front edge rearward in a recessed shape is formed in the first side wall  88  of the retainer rear half  53 . The notch portion  88   a  overlaps with the second fixing piece  57   b  when viewed from the side (see  FIG.  6   ). 
     Next, fixing portions  56  to  64  of the front case  55  and the retainer rear half  53  will be described. 
     The retainer front half  52  of the front case  55  includes the first fixing piece  56   a  and the second fixing piece  57   a  extending outward in the vehicle width direction from the first side wall  66 . Correspondingly, the retainer rear half  53  includes the first fixing piece  56   b  and the second fixing piece  57   b  extending outward in the vehicle width direction from the first side wall  88 . The first fixing piece  56   a  and the first fixing piece  56   b  constitute a first fixing portion  56  (see  FIG.  6   ). The first fixing piece  56   a  and the first fixing piece  56   b  are fastened to each other by a fastener  56   c  (see  FIG.  6   ) inserted into the first fixing portion  56  from the rear side. The second fixing piece  57   a  and the second fixing piece  57   b  constitute a second fixing portion  57  (see  FIG.  6   ). The second fixing piece  57   a  and the second fixing piece  57   b  are fastened to each other by a fastener  57   c  (see  FIG.  6   ) inserted into the second fixing portion  57  from the rear side. 
     As illustrated in  FIG.  8   , the retainer front half  52  includes a third fixing piece  58   a  extending downward from the lower wall portion  68 . The third fixing piece  58   a  is a connecting portion of the second fastening member  75 , and is formed integrally with the second fastening member  75 . Corresponding to the third fixing piece  58   a , the retainer rear half  53  includes a third fixing piece  58   b  extending downward from a lower portion of the rear wall portion  85  in the lower wall portion  90 . The third fixing piece  58   a  and the third fixing piece  58   b  constitute a third fixing portion  58  (see  FIG.  6   ). The third fixing piece  58   a  and the third fixing piece  58   b  are fastened to each other by a fastener  58   c  (see  FIG.  6   ) inserted into the third fixing portion  58  from the rear side. 
     The retainer front half  52  includes a fourth fixing piece  59   a  extending outward in the vehicle width direction from the second side wall  67 . Correspondingly, the retainer rear half  53  includes a fourth fixing piece  59   b  extending outward in the vehicle width direction from the second side wall  89 . The fourth fixing piece  59   a  and the fourth fixing piece  59   b  constitute a fourth fixing portion  59  (see  FIG.  7   ). The fourth fixing piece  59   a  and the fourth fixing piece  59   b  are fastened to each other by a fastener  59   c  inserted into the fourth fixing portion  59  from the rear side. 
     The inflator accommodating portion  51  of the front case  55  includes a fifth fixing piece  60   a  and a sixth fixing piece  61   a  extending upward from the upper wall portion  79 . Correspondingly, the retainer rear half  53  includes a fifth fixing piece  60   b  and a sixth fixing piece  61   b  extending upward from the extending portion upper wall  91 . The fifth fixing piece  60   a  and the fifth fixing piece  60   b  constitute a fifth fixing portion  60  (see  FIG.  7   ). The fifth fixing piece  60   a  and the fifth fixing piece  60   b  are fastened to each other by a fastener  60   c  (see  FIG.  7   ) inserted into the fifth fixing portion  60  from the rear side. 
     The sixth fixing piece  61   a  and the sixth fixing piece  61   b  constitute a sixth fixing portion  61  (see  FIG.  7   ). The sixth fixing piece  61   a  and the sixth fixing piece  61   b  are fastened to each other by a fastener  61   c  (see FIG.  7 ) inserted into the sixth fixing portion  61  from the rear side. 
     The inflator accommodating portion  51  includes a seventh fixing piece  62   a  and an eighth fixing piece  63   a  extending downward from the lower wall portion  80 . Correspondingly, the retainer rear half  53  includes a seventh fixing piece  62   b  and an eighth fixing piece  63   b  extending downward from a lower portion of the side rear wall portion  86  in the lower wall portion  90 . The seventh fixing piece  62   a  and the seventh fixing piece  62   b  constitute a seventh fixing portion  62  (see  FIG.  7   ). The seventh fixing piece  62   a  and the seventh fixing piece  62   b  are fastened to each other by a fastener  62   c  (see  FIG.  7   ) inserted into the seventh fixing portion  62  from the rear side. The eighth fixing piece  63   a  and the eighth fixing piece  63   b  constitute an eighth fixing portion  63  (see  FIG.  7   ). The eighth fixing piece  63   a  and the eighth fixing piece  63   b  are fastened to each other by a fastener  63   c  inserted into the eighth fixing portion  63  from the rear side. 
     The inflator accommodating portion  51  includes a ninth fixing piece  64   a  extending outward in the vehicle width direction from a front surface of the wall portion  78 . A distal end portion  64   a   1  of the ninth fixing piece  64   a  is bent rearward, and the distal end portion  64   a   1  is positioned outside the outer side wall portion  81 . Corresponding to the ninth fixing piece  64   a , the retainer rear half  53  includes a ninth fixing piece  64   b  extending forward from the extending portion side wall  87 . The ninth fixing piece  64   a  and the ninth fixing piece  64   b  constitute a ninth fixing portion  64  (see  FIG.  7   ). The ninth fixing piece  64   a  and the ninth fixing piece  64   b  are fastened to each other by a fastener  64   c  (see  FIG.  6   ) inserted into the ninth fixing portion  64  from the outer side. 
     The retainer  41  can be separated into the front case  55  and the retainer rear half  53  by fastening and unfastening the fixing portions  56  to  64 . This contributes to improvement in assemblability of the airbag device  30 . 
     By fastening the fixing portions  56  to  64 , the front case  55  and the retainer rear half  53  are fastened to form the retainer  41 . 
     In a state where the fixing portions  56  to  64  are fastened, the retainer rear half  53  overlaps with the front case  55  from the outer side. That is, in a state where the fixing portions  56  to  64  are fastened, the first side wall  88  overlaps with the first side wall  66  from the outer side, the second side wall  89  overlaps with the second side wall  67  from the outer side, the lower wall portion  90  overlaps with the lower wall portion  68 , the extending portion lower wall  70   b , and the lower wall portion  80  from the outer side, the extending portion upper wall  91  overlaps with the extending portion upper wall  70   a  and the upper wall portion  79  from the outer side, and the extending portion side wall  87  overlaps with the outer side wall portion  81  from the outer side. At this time, as illustrated in  FIG.  6   , the slit hole  66   a  is exposed to the outside in the vehicle width direction by the notch portion  88   a  of the first side wall  88 . 
     The airbag  42  is housed in the L-shaped airbag passage  47  in the retainer  41  in a folded state, and is provided from the side extending portion  46  to the vertically extending portion  45 . 
     An upstream end of the airbag  42  in the gas flow is sandwiched between the fixing member  44  and the flange portion  43   b , whereby the airbag  42  is connected to the inflator  43 . 
     The exterior member  40  is attached to the retainer  41 . The exterior member  40  is formed in such a way as to cover substantially the entire surface of the retainer  41  except for a lower surface of the retainer  41 . The exterior member  40  includes a cover  100  that covers the retainer  41 , and a lid portion  103  (lid) that covers the opening  48  at the upper surface of the retainer  41  from above, the cover  100  and the lid portion  103  being integrated with each other. The cover  100  is provided on a lower side of the lid portion  103 . The cover  100  includes a vertically extending portion cover portion  101  that covers the vertically extending portion  45  and a side extending portion cover portion  102  that covers the side extending portion  46 , the vertically extending portion cover portion  101  and the side extending portion cover portion  102  being integrated with each other. A lower opening portion  104  that opens a space inside the cover  100  downward is formed in a lower surface of the cover  100 . The lower opening portion  104  is provided in the entire lower surface of the exterior member  40 . The exterior member  40  is attached to the retainer  41  by covering the retainer  41  from above through the lower opening portion  104 . 
     As illustrated in  FIG.  4   , in a first side surface portion  101   c  of an opposite side of the vertically extending portion cover portion  101  from the side extending portion  46 , a fixing portion housing portion  105  formed by making a portion of the first side surface portion  101   c  bulge outward in the vehicle width direction is provided. The first fixing portion  56  and the second fixing portion  57  described above are housed in the fixing portion housing portion  105 . 
     A first attachment hole  105   a  penetrating through a front surface of the fixing portion housing portion  105  is provided in an upper portion of the front surface of the fixing portion housing portion  105 . A cover fastener  108  is inserted into the first attachment hole  105   a . The cover fastener  108  is fastened to a first cover fixing hole portion  56   d  (see  FIG.  8   ) provided in an upper portion of the first fixing piece  56   b.    
     A second attachment hole  105   b  penetrating through the front surface of the fixing portion housing portion  105  is provided in the front surface of the fixing portion housing portion  105  below the first attachment hole  105   a . A cover fastener  109  is inserted into the second attachment hole  105   b . The cover fastener  109  is fastened to a second cover fixing hole portion  57   d  (see  FIG.  8   ) provided in an upper portion of the second fixing piece  57   b.    
     On a side upper surface portion  102   c  of the side extending portion cover portion  102 , a fixing portion housing portion  106  formed by making a portion of the side upper surface portion  102   c  bulge upward is provided. 
     The above-described fourth fixing portion  59 , fifth fixing portion  60 , and sixth fixing portion  61  are housed in the fixing portion housing portion  106 . A third attachment hole  106   a  (see  FIG.  4   ) penetrating through a front surface of the fixing portion housing portion  106  is provided in the front surface. A cover fastener  110  is inserted into the third attachment hole  106   a . The cover fastener  110  is fastened to a third cover fixing hole portion  59   d  (see  FIG.  8   ) provided in an upper portion of the fourth fixing piece  59   b.    
     The exterior member  40  is fastened to the retainer  41  by the cover fasteners  108 ,  109 , and  110 . The exterior member  40  of the present embodiment is engaged with a claw portion (not illustrated) provided on the front surface of the retainer  41 , and is attached to the retainer  41  in a state where a front portion of the exterior member  40  is prevented from coming off upward. 
     Referring to  FIG.  3   , a handlebar holder  11   f  that supports the handlebar  11   e  is provided at an upper end portion of the handlebar post  11   d . The handlebar holder  11   f  has a disk shape in plan view viewed from above, and the handlebar  11   e  is fixed to an upper surface of the handlebar holder  11   f.    
     The airbag unit  31  is disposed in such a way that the lid portion  103  of the exterior member  40  is arranged behind the handlebar holder  11   f.    
     The lid portion  103  of the exterior member  40 , a rear surface portion  101   a , a side rear surface portion  102   a , the fixing portion housing portion  105 , and the fixing portion housing portion  106  are exposed to the straddling space  27 . 
     A lid recessed portion  103   a  recessed downward is provided at a front portion of the lid portion  103  to avoid a rear portion of the handlebar holder  11   f . A front edge of the lid recessed portion  103   a  is formed in an arc shape in accordance with the shape of the rear portion of the handlebar holder  11   f.    
     The rear portion of the handlebar holder  11   f  is disposed in the lid recessed portion  103   a . Therefore, the lid portion  103  can be disposed close to the handlebar holder  11   f  in the front-rear direction of the vehicle. 
     As illustrated in  FIG.  4   , the exterior member  40  includes a tear line  115  and a hinge portion  116  as a cleavage portion broken by the deployed airbag  42 . 
     The tear line  115  and the hinge portion  116  are groove-shaped fragile portions formed to have a plate thickness smaller than a plate thickness of a portion of the exterior member  40  around the tear line  115  and the hinge portion  116 . 
     The tear line  115  is formed to have a plate thickness smaller than that of the hinge portion  116 , and cleaves before the hinge portion  116 . The hinge portion  116  may cleave, but the exterior member  40  is deformed with the hinge portion  116  as a starting point. 
     The tear line  115  includes a rear edge  103   b  of the lid portion  103 , left and right side edges  103   c  of the lid portion  103 , and a lid-side tear line  115   a  provided in a portion excluding a portion of the lid recessed portion  103   a  in a front edge  103   d  of the lid portion  103 . The tear line  115  includes a pair of left and right rear tear lines  115   b  extending downward along the left and right side edges of the rear surface portion  101   a  from portions of the left and right end portions of the rear edge  103   b  in the lid-side tear line  115   a . Furthermore, the tear line  115  includes a pair of left and right front tear lines (not illustrated) extending downward along the left and right side edges of a front surface portion  101   b  from the left and right end portions of the front edge  103   d  in the lid-side tear line  115   a.    
     The hinge portion  116  linearly extends in the vehicle width direction between the rear edge  103   b  and the lid recessed portion  103   a  on the upper surface of the lid portion  103 . 
     The exterior member  40  covers a range from the upper end portion to the lower end portion of the retainer  41 , and covers substantially the entire retainer  41  except for the lower surface and a lower-left portion of the front surface of the retainer  41  from the outer side. Here, the upper end portion of the retainer  41  is the opening  48 , and the lower end portion of the retainer  41  is lower edges of the rear wall portion  85  and the side rear wall portion  86 . 
     Therefore, the retainer  41  can be entirely covered from above and surrounded by the exterior member  40 , and the waterproofness of the retainer  41  can be improved. 
     In the airbag device  30  of the present embodiment, the inflator  43  ejects gas into the airbag  42  toward the rear side of the vehicle along the axis  43   c  under the control of the airbag control device. 
     The gas discharged from the inflator  43  into the airbag  42  is guided by the side extending portion  46  and the vertically extending portion  45 , and flows in an L shape in the airbag passage  47 . 
     At this time, a part of the gas ejected from the inflator  43  hits the stepped shape  93  of the side extending portion  46  via the airbag  42  and flows inward in the vehicle width direction along the stepped shape  93 . 
     When the gas flows from the side extending portion  46  to the vertically extending portion  45 , the flow in the left-right direction is changed to the flow in the upward direction, and the gas flows upward in the vertically extending portion  45 . 
     When the airbag  42  inflates upward by the gas flowing upward in the vertically extending portion  45 , the exterior member  40  cleaves starting from the portions of the tear line  115  and the hinge portion  116 , the lid portion  103  is opened, and the opening  48  is exposed. Then, the airbag  42  is deployed upward from the opening  48  as illustrated in  FIG.  1    by the gas flowing upward. 
     The retainer  41  is fastened to the down frame  16  at a lower side position of the retainer  41  via the second fastening member  75 . As a result, the support rigidity of a lower portion of the retainer  41  with respect to the vehicle body frame  10  side is increased, and when the airbag  42  inflates by the gas, a portion of an upper portion of the retainer  41  on the opening  48  side slightly moves toward the occupant side with a portion of the second fastening member  75  as a fulcrum due to the inflation of the airbag  42 , and is deformed to widen the opening  48 . Therefore, the airbag  42  can be satisfactorily deployed upward. 
       FIG.  10    is a view of the deployed and inflating airbag  42  as viewed from the rear side (corresponding to the occupant side).  FIG.  11    is a view of the deployed and inflating airbag  42  as viewed from the front side (a side opposite from the occupant). 
     The airbag  42  is a bag including a proximal end portion  121  positioned in the airbag passage  47  (see  FIG.  8   ) of the retainer  41  in a deployed state and an outward deployment portion  122  positioned outside the airbag passage  47  in a deployed state, the proximal end portion  121  and the outward deployment portion  122  being integrated with each other. 
     The outward deployment portion  122  is formed bilaterally symmetrically with respect to a center line (left-right center line) C 1  of the outward deployment portion  122  in the width direction (left-right direction). The airbag  42  is disposed in such a way that the center line C 1  is positioned on the left side of the center of the vehicle width. The airbag  42  is disposed in such a way that the center line C 1  is at the same position as a center line  47 C (see  FIGS.  4  and  5   ) of the vertically extending portion  45  of the retainer  41  in the vehicle width direction. 
     The outward deployment portion  122  includes a neck portion  122 A extending upward from an upper end of the proximal end portion  121 , a deployment portion main body  122 B extending upward from an upper end of the neck portion  122 A, and a bulging portion  122 C bulging upward from the center of the upper portion of the deployment portion main body  122 B in the width direction. 
     The neck portion  122 A is a cylindrical portion extending in the vertical direction from the opening  48  of the retainer  41  in a state where the airbag  42  is operated and deployed. 
     The deployment portion main body  122 B is formed in a fan shape extending upward and having a width in the left-right direction increasing from a lower end which is a connecting portion with the neck portion  122 A. The deployment portion main body  122 B includes a head facing portion  122 D having the maximum width in the left-right direction at an upper end portion thereof. The head facing portion  122 D is a portion assumed to receive the head of the occupant in a state where the airbag  42  is operated and deployed. 
     The neck portion  122 A, the deployment portion main body  122 B, and the bulging portion  122 C are provided bilaterally symmetrically with respect to the center line C 1 . 
     The airbag  42  of the present embodiment is formed in a bag shape by a joining structure of a front base fabric (front surface)  123  (see  FIG.  11   ) and a rear base fabric (rear surface)  124  (see  FIG.  10   ). A sewn portion (coupling portion)  131  for forming the joining structure in which the front base fabric  123  and the rear base fabric  124  are sewn together is formed at peripheral edge portions of the front base fabric  123  and the rear base fabric  124 . 
     The deployment portion main body  122 B includes a pair of middle sewn portions  133  and  133  at positions between the neck portion  122 A and the head facing portion  122 D. The middle sewn portions  133  and  133  are provided bilaterally symmetrically with respect to the center line C 1 . 
     The middle sewn portions  133  and  133  are portions where the front base fabric  123  and the rear base fabric  124  of the outward deployment portion  122  are sewn and connected along peripheral edge portions of the middle sewn portions  133  and  133 , and the gas G does not pass through the middle sewn portions  133  and  133 . 
     A throttle portion  135  in which the passage of the gas G becomes narrower than that on the upstream side is formed between the left and right middle sewn portions  133  and  133 . In addition, throttle portions  136  and  136  in which the passage of the gas G becomes narrower than that on the upstream side are formed between left and right side portions of the outward deployment portion  122  and the middle sewn portions  133  and  133 . 
     Since the passage of the gas G on the upstream side of the head facing portion  122 D become narrower by the throttle portion  135 ,  136 , and  136 , the gas G is quickly supplied to the head facing portion  122 D. 
       FIG.  12    is an explanatory view of panels  125  and  125  forming a circumferential length difference. 
     The airbag  42  of the present embodiment includes the panels  125  and  125  that are sewn to the sewn portion  131  of the front base fabric  123  and the rear base fabric  124  to form a circumferential length difference between the front base fabric  123  and the rear base fabric  124  when viewed from the side. The panels  125  and  125  are formed of fabric similarly to the front base fabric  123  and the rear base fabric  124 . A pair of panels  125  and  125  are provided on the left and right sides of the neck portion  122 A. In  FIG.  12   , the left panel  125  is illustrated in a left side view, and the right panel  125  is illustrated in a right side view. The panels  125  and  125  are configured to be bilaterally symmetrical. 
     The panels  125  and  125  are substantially D-shaped in a side view. Each of the panels  125  and  125  includes a front edge portion  126  and a rear edge portion  127  facing the front edge portion  126 . Each of the panels  125  and  125  includes a first edge portion  129  connecting one end of the front edge portion  126  in a circumferential direction and one end of the rear edge portion  127  in the circumferential direction, and a second edge portion  130  connecting the other end of the front edge portion  126  in the circumferential direction and the other end of the rear edge portion  127  in the circumferential direction. In a side view, the front edge portion  126  and the rear edge portion  127  are formed in an arc shape recessed rearward, and the front edge portion  126  has a shorter circumferential length than the rear edge portion  127 . In a side view, the first edge portion  129  and the second edge portion  130  extend substantially linearly, and the circumferential lengths of the first edge portion  129  and the second edge portion  130  are substantially the same. 
     The peripheral edge portion of the front base fabric  123  and the front edge portion  126  of the panel  125  are sewn while facing each other. The circumferential length of the peripheral edge portion of the front base fabric  123  corresponds to the circumferential length of the front edge portion  126  of the panel  125  in a side view at a portion sewn to the panel  125 . 
     A peripheral edge portion  124 C of the rear base fabric  124  and the rear edge portion  127  of the panel  125  are sewn while facing each other. The circumferential length of the peripheral edge portion of the rear base fabric  124  corresponds to the circumferential length of the rear edge portion  127  of the panel  125  in a side view at a portion sewn to the panel  125 . 
     In the neck portion  122 A of the outer deployment portion  122 , the front base fabric  123  is shorter, and the rear base fabric  124  is longer. Since there is a circumferential length difference between the front base fabric  123  and the rear base fabric  124  in a direction along the center line C 1 , the airbag  42  is easily deployed in a state of being bent toward a certain front side of the front base fabric  123  in the direction along the center line C 1  at the time of deployment. 
     The neck portion  122 A is a cylindrical portion extending in the vertical direction from the opening  48  of the retainer  41 , and is positioned below the handlebar  11   e  in the vehicle side view in a deployed state. Therefore, the panels  125  formed at the neck portion  122 A are positioned below the handlebar  11   e  in the vehicle side view, and the airbag  42  is deployed in this state. Therefore, the airbag  42  is easily deployed upward behind the handlebar  11   e  through below the handlebar  11   e , and the airbag  42  can be deployed while suppressing interference with the handlebar  11   e.    
     In particular, the panel  125  in the present embodiment is disposed upstream of the deployment portion main body  122 B including the head facing portion  122 D and greatly expanding in the left-right direction, in a flow direction of the gas G. Therefore, it is possible to deploy the airbag  42  while suppressing the deployment portion main body  122 B from interfering with portions of the handlebar  11   e  positioned on the left and right sides of the handlebar post  11   d.    
     As illustrated in  FIGS.  10  and  11   , in the airbag  42 , the proximal end portion  121  connected to the inflator  43  includes a bag left-right extending portion  121 A extending in the left-right direction in the side extending portion  46  of the retainer  41  and a bag upward extending portion  121 B extending upward from the bag left-right extending portion  121 A. 
     The bag left-right extending portion  121 A extends in the left-right direction from the inflator  43  of the retainer  41  toward the center line C 1 . 
     The bag upward extending portion  121 B extends upward while being slightly inclined with respect to the center line C 1  in the vertically extending portion  45 . The outward deployment portion  122  extending upward is continuous with an upper end of the bag upward extending portion  121 B. 
     In the proximal end portion  121 , the bag left-right extending portion  121 A extends toward one side in the vehicle width direction with respect to the center line C 1 , and is formed to be bilaterally asymmetrical with respect to the center line C 1 . 
     That is, in the airbag  42 , the outward deployment portion  122  is bilaterally symmetrical with respect to the center line C 1 , but the proximal end portion  121  is provided bilaterally asymmetrically with respect to the center line C 1  along the L-shaped airbag passage  47 . 
     An angle at which an extending direction X 1  of the bag left-right extending portion  121 A and an extending direction Y 1  of the bag upward extending portion  121 B intersect is larger than a right angle. The proximal end portion  121  is formed in an L shape along the airbag passage  47  of the retainer  41 . 
     When housed in the retainer  41 , the proximal end portion  121  has a shape curved at a substantially right angle along the airbag passage  47 . 
     In the peripheral edge portion of the proximal end portion  121 , curved portions  121 C and  121 D are formed at a connecting portion between the bag left-right extending portion  121 A and the bag upward extending portion  121 B. The gas G smoothly flows along the curved portions  121 C and  121 D. 
     A connecting port  121 E (see  FIG.  11   ) connected to the inflator  43  is provided at a position offset from the center line C 1  of the bag left-right extending portion  121 A in the vehicle width direction in the front base fabric  123  of the proximal end portion  121 . 
       FIG.  13    is a front view of a loop diffuser  141 . 
     The airbag  42  includes the loop diffuser  141  that guides the gas G. The loop diffuser  141  is formed in an L-shaped bag shape including an opening  141 A at one end thereof. A peripheral edge portion of the loop diffuser  141  is closed except for the opening  141 A. 
     The loop diffuser  141  is disposed in the gas flow path of the proximal end portion  121  and extends from the inflator  43  to a lower end portion of the outward deployment portion  122 . The loop diffuser  141  is coupled to the airbag  42  by being sewn to an inner surface of the proximal end portion  121 . 
     The loop diffuser  141  includes a connecting portion  141 B connected to the inflator  43 . The connecting portion  141 B is connected to the inflator  43  in such a way as to overlap with the connecting port  121 E of the bag left-right extending portion  121 A from the inner side. The gas G discharged from the inflator  43  directly flows into the bag of the loop diffuser  141  from the connecting portion  141 B. The gas G flowing into the loop diffuser  141  flows along the loop diffuser  141  and flows into the outward deployment portion  122  from the opening  141 A. 
     The opening  141 A is disposed in such a way that the gas G discharged from the opening  141 A flows upward. 
     Since the flow direction of the gas G from the inflator  43  can be controlled by the loop diffuser  141 , a filling procedure for filling the airbag  42  with the gas G can be controlled, and the airbag  42  can be efficiently deployed upward. 
     Further, in the proximal end portion  121 , the strength of the airbag  42  is secured by the loop diffuser  141 . The proximal end portion  121  is a portion that receives the gas G immediately after the injection from the inflator  43 , but since the strength of the proximal end portion  121  is secured, the shape of the proximal end portion  121  is easily stabilized, and the airbag  42  can be efficiently deployed in a state where the posture is stabilized. 
     As illustrated in  FIGS.  10  and  11   , a right pipe portion  137  is formed at a lower portion of an inner peripheral side of the right middle sewn portion  133 . A left pipe portion  138  is formed at a lower portion of an inner peripheral side of the left middle sewn portion  133 . The pipe portions  137  and  138  sew the front base fabric  123  and the rear base fabric  124  in a circular shape. 
     A right side tab  139  and a left side tab  140  are provided on the proximal end portion  121 . The side tabs  139  and  140  are fabrics separate from the front base fabric  123  and the rear base fabric  124 . The side tabs  139  and  140  are disposed between the front base fabric  123  and the rear base fabric  124  and are sewn to the sewn portion  131 . 
     The right side tab  139  is sewn in a state of extending toward one side in the left-right direction from the right curved portion  121 D of the proximal end portion  121 . The right side tab  139  overlaps with a line L 2  passing through the center of the inflator  43  and extending along the longitudinal direction X 1  of the bag left-right extending portion  121 A in a vehicle front view. 
     The left side tab  140  is sewn in a state of extending toward the other side in the left-right direction from the left curved portion  121 C of the proximal end portion  121 . The left side tab  140  is disposed above the right side tab  139  in the vehicle front view. 
     Anchoring bodies  171  and  172  are disposed between the pipe portions  137  and  138  and the side tabs  139  and  140 . The anchoring bodies  171  and  172  are formed of a belt-shaped fabric extending in the vertical direction. 
     The right anchoring body  171  includes an upper end  171 A sewn to an inner side of the right pipe portion  137 , an upper straight portion  171 B linearly extending downward from the upper end  171 A, an inclined portion  171 C extending downward from the upper straight portion  171 B and becoming away from the center line C 1  toward the lower side, a lower straight portion  171 D linearly extending downward from the inclined portion  171 C, and a lower end portion  171 E formed at a lower end of the lower straight portion  171 D and sewn to a front surface of the right side tab  139 . In the right anchoring body  171 , a lower portion of the inclined portion  171 C extends into the retainer  41 , and an upper portion of the inclined portion  171 C overlaps with the outward deployment portion  122  in a deployed state. 
     The left anchoring body  172  includes an upper end  172 A sewn to an inner side of the left pipe portion  138 , an upper straight portion  172 B linearly extending downward from the upper end  172 A, an inclined portion  172 C extending downward from the upper straight portion  172 B and approaching the center line C 1  toward the lower side, a lower straight portion  172 D linearly extending downward from the inclined portion  172 C, and a lower end portion  172 E formed at a lower end of the lower straight portion  172 D and sewn to a front surface of the left side tab  140 . In the left anchoring body  172 , the lower straight portion  172 D extends along a left side portion of the neck portion  122 A, and the inclined portion  172 C substantially entirely overlaps with the outward deployment portion  122  in a deployed state. 
     The proximal end portion  121  and the outward deployment portion  122  are connected by the anchoring body  171  on the right side with respect to the center line C 1  and are connected by the anchoring body  172  on the left side. Here, the inflator  43  is disposed on the left side of the center line C 1 , and a force tilting to the left or right is likely to act on the proximal end portion  121  by the gas G moving upward from the left and right direction. On the other hand, in the present embodiment, the anchoring bodies  171  and  172  are connected, and distances between the pipe portions  137  and  138  and the side tabs  139  and  140  are restricted from excessively increasing on the right side and the left side with respect to the center line C 1 . As a result, it is possible to deploy the airbag  42  while suppressing the airbag  42  from being inclined in the front-rear direction. 
     A fixing tab (tab)  161  is provided below the side tabs  139  and  140 . The fixing tab  161  is a fabric separate from the front base fabric  123  and the rear base fabric  124 . The fixing tab  161  is sewn to the sewn portion  131  while being sandwiched between the front base fabric  123  and the rear base fabric  124 . A fixing hole  161 A penetrating in the thickness direction is formed in the fixing tab  161 . 
     The fixing tab  161  is provided on a side opposite from the inflator  43  in the longitudinal direction X 1  of the bag left-right extending portion  121 A. The fixing tab  161  of the present embodiment extends rightward, that is, toward the side opposite from the inflator  43 , from the curved portion  121 D bulging toward the side opposite from the inflator  43 . The fixing tab  161  is provided below the line L 2  passing through the center of the inflator  43  and extending along the bag left-right extending portion  121 A in the front view. 
     When the airbag  42  is housed in the front case  55 , the fixing tab  161  is led out to the outside through the slit hole  66   a . When the front case  55  and the retainer rear half  53  are assembled, the fixing tab  161  is sandwiched between the second fixing piece  57   a  of the front case  55  and the second fixing piece  57   b  of the retainer rear half  53 . Then, the fastener  57   c  is inserted through the second fixing piece  57   a  of the front case  55 , the second fixing piece  57   b  of the retainer rear half  53 , and the fixing hole  161 A of the fixing tab  161 , and the fixing tab  161  is fastened together to the second fixing pieces  57   a  and  57   b . That is, the fixing tab  161  is fixed to the component of the retainer  41  outside the retainer  41 . 
     In the present embodiment, the fixing tab  161  is led out to the outside of the retainer  41  through the slit hole  66   a . However, for example, the slit hole  66   a  may be omitted, a fixing portion may be provided in the airbag passage  47  of the first side wall  66 , and the fixing tab  161  may be fixed to the fixing portion. 
     Next, the operation of the present embodiment will be described. 
     Once the inflator  43  of the airbag device  30  operates, the gas G is injected into the airbag  42 . The airbag  42  inflates by a pressure of the gas G and deployed upward. 
     That is, when the inflator  43  operates, the gas G is injected to the loop diffuser  141 . The gas G is guided by the loop diffuser  141  to move through the L-shaped proximal end portion  121 . The gas G having passed through the proximal end portion  121  enters the outward deployment portion  122  to deploy the outward deployment portion  122 . 
     At this time, the exterior member  40  of the airbag device  30  is broken, and the outward deployment portion  122  is deployed from the opening  48 . In the present embodiment, the second fastening member  75  increases the support rigidity of the lower portion of the retainer  41 , and when the airbag  42  inflates, the portion of the upper portion of the retainer  41  on the opening  48  side slightly moves toward the occupant side with the portion of the second fastening member  75  as a fulcrum, and is deformed to widen the opening  48 . Therefore, the outward deployment portion  122  of the airbag  42  is easily deployed rearward immediately after the inflation. 
     Once the outward deployment portion  122  is deployed rearward, the neck portion  122 A is positioned directly below the handlebar  11   e  in the vehicle side view as illustrated in  FIG.  1   . The panels  125  and  125  are sewn to the neck portion  122 A, and a circumferential length difference is generated between the front base fabric  123  and the rear base fabric  124  in such a way that that the front base fabric  123  is shorter. Therefore, the airbag  42  that pops out rearward from the retainer  41  is easily bent toward the front base fabric  123  and deployed upward after passing below the handlebar  11   e . In the present embodiment, it is easy to deploy the airbag  42  while suppressing the airbag  42  from coming into contact with the handlebar  11   e.    
     In the proximal end portion  121  of the airbag  42 , the fixing tab  161  is provided on the side opposite from the inflator  43  in the longitudinal direction X 1  of the bag left-right extending portion  121 A, and the fixing tab  161  is fixed to the retainer  41 . The gas G injected from the inflator  43  moves along the longitudinal direction X 1  of the bag left-right extending portion  121 A, and then moves upward along the bag upward extending portion  121 B. For this reason, there is a possibility that the airbag  42  loses its balance in the left-right direction due to a force of moving upward from the gas G at the proximal end portion  121 . On the other hand, in the present embodiment, since the fixing tab  161  is fixed to the retainer  41 , it is easy to ensure the balance of the airbag  42 , and it is easy to deploy the airbag  42  while suppressing the airbag  42  from being inclined in the left-right direction. 
     In particular, the fixing tab  161  is provided below the line L 2  passing through the center of the inflator  43  in the front view. Therefore, the airbag  42  can be fixed at the base side of the airbag  42  by the connecting portion  141 B with the inflator  43  and the fixing tab  161 , and the airbag  42  can be deployed while suppressing the airbag  42  from being inclined in the left-right direction. 
     In the present embodiment, since the proximal end portion  121  and the outward deployment portion  122  are connected by the pair of left and right anchoring bodies  171  and  172 , the outward deployment portion  122  and the proximal end portion  121  are deployed while being restricted from excessively increasing in distance therebetween. Therefore, the airbag  42  is deployed while the airbag  42  is suppressing from being inclined in the front-rear direction. 
     As described above, in the present embodiment, the airbag  42  is efficiently deployed while being suppressed from coming into contact with the handlebar  11   e  (see  FIG.  1   .) 
     As described above, according to the embodiment to which the present invention is applied, the saddle riding-type vehicle includes: the retainer  41  that is provided behind the head pipe  15 ; the inflator  43 ; and the airbag  42  that is housed in the retainer  41 , inflates by the gas G discharged by the inflator  43 , and is deployed in front of an occupant, in which the retainer  41  is disposed below the handlebar  11   e , the airbag  42  is formed in a bag shape by the joining structure of the front base fabric  123  and the rear base fabric  124 , and the panels  125  that form a circumferential length difference between the front base fabric  123  and the rear base fabric  124  in the side view are provided at the coupling portion  131  between the front base fabric  123  and the rear base fabric  124 . Therefore, it is possible to deploy the airbag  42  while suppressing interference with the handlebar  11   e.    
     In the present embodiment, the panels  125  are positioned below the handlebar  11   e  when the airbag  42  is deployed. Therefore, the airbag  42  can have a circumferential length difference below the handlebar  11   e , and the airbag  42  can be bent and deployed below the handlebar  11   e , so that the airbag  42  can be made less likely to interfere with the handlebar  11   e.    
     In the present embodiment, the airbag  42  includes the proximal end portion  121  positioned in the retainer  41  when the airbag  42  is deployed, the neck portion  122 A extending upward from the upper end of the proximal end portion  121  and deployed to the outside of the retainer  41  when the airbag  42  is deployed, and the deployment portion main body  122 B extending upward and having a width in the left-right direction increasing from the upper end of the neck portion  122 A, and the panels  125  may be provided at the neck portion  122 A. Therefore, the deployment portion main body  122 B greatly expanding in the left-right direction can easily avoid the handlebar  11   e.    
     The neck portion  122 A includes the side tabs  139  and  140 , and the anchoring bodies  171  and  172  extending from the deployment portion main body  122 B are connected to the side tabs  139  and  140 . Therefore, it is possible to deploy the airbag  42  while suppressing the airbag  42  from being inclined in the front-rear direction. 
     According to the embodiment to which the present invention is applied, the saddle riding-type vehicle includes: the retainer  41  that is provided behind the head pipe  15 ; the inflator  43 ; and the airbag  42  that is housed in the retainer  41 , inflates by the gas G discharged by the inflator  43 , and is deployed in front of the occupant, in which the airbag  42  includes the proximal end portion  121  that is positioned in the retainer  41  when the airbag  42  is deployed, and the outward deployment portion  122  that extends from the proximal end portion  121  and is deployed to the outside of the retainer  41  when the airbag  42  is deployed, a fixing tab  161  is provided on the proximal end portion  121 , and the fixing tab  161  is fixed to the retainer  41 . Therefore, it is possible to deploy the airbag  42  while suppressing the airbag  42  from being inclined in the left-right side. 
     In the present embodiment, the slit hole  66   a  into which the fixing tab  161  is inserted is formed in the first side wall  66  constituting the side surface of the retainer  41 , and the fixing tab  161  is fixed to an outer side of the retainer  41  through the slit hole  66   a . Therefore, the fixing portion of the fixing tab  161  can be hardly affected by the gas G injected from the inflator  43 . 
     In the above configuration, the proximal end portion  121  includes the bag left-right extending portion  121 A connected to the inflator  43  and the bag upward extending portion  121 B extending upward from the bag left-right extending portion  121 A, and the fixing tab  161  is provided on a side opposite from the inflator  43  in the longitudinal direction X 1  of the bag left-right extending portion  121 A. Therefore, it is possible to fix, to the retainer  41 , a portion of the airbag  42  that is hardly affected by the gas G injected from the inflator  43 , and it is possible to suppress the airbag from being inclined in the left-right direction. 
     In the present embodiment, the fixing tab  161  is provided below the line L 2  passing through the center of the inflator  43  and extending along the bag left-right extending portion  121 A in a front view. Accordingly, since the fixing tab  161  is positioned below the line L 2 , the airbag  42  can be fixed at the base side together with the connecting portion  141 B with the inflator  43 , and it is possible to deploy the airbag  42  deployed while suppressing the airbag  42  from being inclined in the left-right direction. 
     In the present embodiment, the loop diffuser  141  that guides the gas G is provided in the inflator  43 , and the loop diffuser  141  is disposed in the gas flow path of the proximal end portion  121 . Therefore, it is possible to reinforce the proximal end portion  121 , and it is possible to deploy the airbag  42  while stabilizing the posture of the proximal end portion  121 . 
     The above embodiment illustrates one aspect to which the present invention is applied, and the present invention is not limited to the above embodiment. 
     In the above embodiment, a configuration in which one fixing tab  161  and one slit hole  66   a  are provided has been described, but the number of fixing tabs  161  and the number of slit holes  66   a  are not limited to one, and a plurality of fixing tabs  161  and slit holes  66   a  may be provided. 
     Further, in the above embodiment, a configuration in which the anchoring bodies  171  and  172  are provided has been described, but the anchoring body  172  may be omitted. 
     In addition, in the above embodiment, the motorcycle  1  has been described as an example of the saddle riding-type vehicle. The present invention, however, is not limited thereto, and thus the present invention is applicable to a three-wheeled saddle riding-type vehicle having two front wheels or two rear wheels, and a saddle riding-type vehicle having four or more wheels. 
     REFERENCE SIGNS LIST 
     
         
           1  Motorcycle (saddle riding-type vehicle) 
           15  Head pipe 
           41  Retainer 
           42  Airbag 
           43  Inflator 
           66  First side wall (side surface) 
           66   a  Slit hole (opening portion) 
           121  Proximal end portion 
           121 A Bag left-right extending portion 
           121 B Bag upward extending portion 
           122  Outward deployment portion 
           141  Loop diffuser 
           161  Fixing tab (tab) 
         G Gas 
         L 2  Line passing through center of inflator 
         X 1  Longitudinal direction