Patent Publication Number: US-11390237-B2

Title: Air bag lid reinforcing member and method for manufacturing same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This is a U.S. national phase application of PCT/JP2019/024416, filed on Jun. 20, 2019, which claims priority to Japanese Patent Application 2018-118008 filed in Japan on Jun. 21, 2018. The entire disclosure of Japanese Patent Application 2018-118008 is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present case relates to an airbag lid reinforcing member and the manufacturing method therefor. 
     BACKGROUND ART 
     In vehicles such as automobiles, an airbag device is provided as a safety measure for emergencies (e.g. see Japanese Laid Open Patent Publication No. 2007-62701, French Patent Publication No. FR3015393). 
     In Japanese Laid Open Patent Publication No. 2007-62701, a door part (first backing plate) and a flange part (second backing plate) are connected by a mesh hinge member (easy bending material). With this kind of hinge member, when the airbag is deployed, it is assumed that the boundary part of the hinge member and the flange part (specifically, the root part that protrudes from the flange part in the hinge member) is a fulcrum for rotation. 
     In French Patent Publication No. FR3015393 as well, a flange part (part indicated by 18 in the document), and a door part (parts indicated by code numbers 34, 42 in the document) are connected by a hinge connecting member (part indicated by code number 36 in the document). 
     SUMMARY 
     The inventor of the present application discovered that there are the following problems for the inventions of Japanese Laid Open Patent Publication No. 2007-62701 and French Patent Publication No. FR3015393 described above. Specifically, with the invention of Japanese Laid Open Patent Publication No. 2007-62701, there is a risk that the cloth of the airbag inflated toward the door during deployment of the airbag will directly touch the boundary part of the hinge member and the flange part. In that case, shearing force is applied to the part that becomes the fulcrum for rotation in the hinge member. 
     In contrast, with French Patent Publication No. FR3015393, as shown in FIG. 4b of the document, a step part is formed by the end surface of the flange part and the top surface of the leg part, and the hinge member is exposed from the flange part at the top surface of the leg part. If the structure of this French Patent Publication No. FR3015393 is faithfully realized, the fulcrum for rotation of the hinge member is positioned further to the outside than the inner surface of the leg part, and is protected from the cloth of the airbag. 
     However, with the invention noted in the above-mentioned French Patent Publication No. FR3015393, in the hinge member, there is a risk that a resin layer will be formed on the entire top side of the part exposed from the flange part on the leg part. 
     Specifically, with the configuration of French Patent Publication No. FR3015393 noted above, when doing insertion molding of the hinge member in the flange part and the leg part, within the mold, the part that becomes the fulcrum for rotation in the hinge member is positioned on the molding space that forms the leg part. However, that molding space does not support the hinge member. For this reason, there is a risk that when injecting resin, the hinge member will bend due to injection pressure, the leg part will be molded in a state with the hinge member entered into the molding space, and the hinge member will end up creeping into the leg part. As a result, in the hinge member, the location that is exposed from the resin and becomes the fulcrum for rotation ends up moving to the inner surface side of the leg part. When that happens, ultimately this is the same as with the configuration of Japanese Laid Open Patent Publication No. 2007-62701, with the cloth of the airbag directly touching the fulcrum for rotation, and the problem relating to shearing stress on the hinge member accompanying deployment of the airbag occurring. 
     In light of this, the main purpose of the present case is to address the problems noted above. 
     To address the problems noted above, the present case is an airbag lid reinforcing member comprising: a door part that can open and close, a flange part made of resin that surrounds the outer periphery of the door part, a leg part made of resin installed on the lower side of the flange part, and a hinge member that is configured by at least a member separate from the flange part, and that connects the flange part and the door part to be able to open and close, wherein on the inside surface of the leg part, a plurality of support ribs that support the hinge member from the lower surface side are provided having a gap in the width direction of the leg part, a portion of the hinge member is buried in the flange part, in the portion of the hinge member on the support rib, in the range from the tip of the support rib to the end surface of the flange part, at least the upper part in the thickness direction of the hinge member is exposed from the support rib, and the portion of the hinge member positioned between support ribs is exposed from the support rib and the flange part. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a vertical cross section diagram of an airbag device of the present embodiment. 
         FIG. 2  is a cross section diagram viewing a leg part from the position of line II-II of  FIG. 1 . 
         FIG. 2A  is a partial plan view of an airbag lid reinforcing member of  FIG. 1 . 
         FIG. 2B  is a partial plan view of the lower mold of a mold device for manufacturing. 
         FIG. 3  is an enlarged view of a part without support ribs in  FIG. 1 , and a cross section diagram of line A-A in  FIG. 2A . 
         FIG. 4  is an enlarged view of a part having support ribs in  FIG. 1 , and is a cross section diagram of line B-B in  FIG. 2A . 
         FIG. 5  is a partial enlarged view of a modification example of  FIG. 4 . 
         FIG. 6  is a partial enlarged view of another modification example of  FIG. 4 . 
         FIG. 7  is a vertical cross section diagram of a mold device for manufacturing the airbag lid reinforcing member. 
         FIG. 8  is a cross section diagram along line C-C in  FIG. 2B  corresponding to the upper peripheral part (part without support ribs) of the leg part of the mold device for manufacturing in  FIG. 7 . 
         FIG. 9  is a cross section diagram along line D-D in  FIG. 2B  corresponding to the upper peripheral part (part with support ribs) of the leg part of the mold device for manufacturing in  FIG. 7 . 
         FIG. 10  is a partial enlarged view of the same kind of mold device for manufacturing as in  FIG. 8  for a modification example in  FIG. 4 . 
         FIG. 11  is a partial enlarged view of the same kind of mold device for manufacturing as in  FIG. 8  for another modification example in  FIG. 5 . 
         FIG. 12  is an enlarged partial cross sectional diagram corresponding to  FIG. 4  illustrating a state in which the air bag body has been deployed. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Hereafter, the present embodiment is explained in detail using the drawings. 
       FIG. 1  to  FIG. 11  are for explaining this embodiment. 
     Embodiment 1 
     Configuration 
     Hereafter, the configuration of this embodiment is explained. 
       FIG. 1  shows an airbag device. The directions in the drawing are vehicle front-rear direction X, vehicle width direction Y, and vertical direction Z. 
     In a vehicle  1  such as an automobile, an airbag device  3  is provided inside a passenger compartment  2  as a safety measure for emergencies. For example, the airbag device  3  for the passenger seat comprises an airbag module  5  that houses a folded bag-shaped airbag body  4 , a lid member  6 , and an airbag lid reinforcing member  31 . 
     During deployment, the airbag body  4  expands from an opening part formed on the top surface side of the airbag module  5  diagonally upward and backward facing the occupant side. In  FIG. 1 , the expansion direction of the airbag body  4  is noted as code number  41 . In this way, to expand the airbag body  4 , the airbag module  5  is placed tilted with respect to the surface of the lid member  6  facing in approximately the vertical direction Z in a state with the opening part of the top surface of the airbag module  5  facing the occupant side. 
     The lid member  6  conceals the airbag module  5  from above at normal times, and also forms an opening  61  by which the airbag body  4  deployed from the airbag module  5  is expanded toward inside the passenger compartment  2  during an emergency. The lid member  6  has a lid section  21  that is opened by the airbag body  4 , and a lid outer periphery part  22  that surrounds the outer periphery of the lid section  21 . 
     With this embodiment, two lid sections  21  are provided in a vehicle front-rear direction X (first lid section (vehicle front side) and second lid section (vehicle rear side)). The lid section  21  and the lid outer periphery part  22  are defined by a cleavage line  23 . The cleavage line  23  is a notch formed on the rear surface side of the lid member  6 , at a depth that does not reach the surface of the lid member  6 . The lid member  6  includes items that are integrated with an instrument panel  8 , and items that are separate from the instrument panel  8 . Generally, the instrument panel  8  has a top surface part positioned under a front window and facing approximately the vertical direction Z, and a front side surface part that extends approximately downward from the edge part of the occupant side of the top surface part, and the lid member  6  is provided at the position of the top surface part. 
     The airbag lid reinforcing member  31  is attached to the rear surface side of the lid member  6  to reinforce the lid member  6 , houses at least a portion of the airbag module  5 , and guides the airbag body  4  deployed from the airbag module  5  to the lid member  6 . 
     The airbag lid reinforcing member  31  has a door part  32 , a flange part  33 , a leg part  34 , and a hinge part  35 . Among these, two door parts  32  are provided in the vehicle front-rear direction X (first door part (vehicle front side) and second door part (vehicle rear side)), these are attached to the rear surface of each lid section  21  to reinforce each lid section  21 , and integrated with the lid section  21  to be able to open and close. 
     The flange part  33  surrounds the outer periphery of the door part  32  with a gap in the circumferential direction, and is attached to the rear surface of the lid outer periphery part  22  to reinforce the lid outer periphery part  22 . Welding ribs  36 ,  37  for welding to the lid member  6  are provided on the front surface of the door part  32  and the flange part  33 . 
     The leg part  34  is installed below the door part  32  and the flange part  33  in a state surrounding the upper part of the airbag module  5 . In the leg part  34 , the upper part of the airbag module  5  is made to be inserted from below, and the leg part  34  functions as a guide part for guiding the deployed airbag body  4  toward the door part  32  and the lid section  21 . For that reason, the leg part  34  is in an approximate frame shape surrounding the position of the outside of the door part  32  or the outer periphery side of the door part  32  and extending in the expansion direction  41  (see  FIG. 1 ) to inside the passenger compartment  2 . 
     With the present embodiment, as described above, the configuration is such that the airbag module  5  is placed tilted in a state facing the occupant side, and in the opening  61  of the lid member  6 , the expansion direction  41  of the airbag body  4  is tilted (at least it is not orthogonal) with respect to the virtual straight line connecting the end part of the vehicle front side and the end part of the vehicle rear side. As a result, when the leg part  34  is seen from the side, the occupant side (rear side) is longer than the front window side (front side). Specifically, the distance from the airbag module  5  to the occupant side hinge part  35  is longer than the distance from the airbag module  5  to the front window side (front side) hinge part  35 . 
     Also, a hook part  42  is provided on the front and back side surfaces of the upper part of the airbag module  5 , and a locking hole  43  that can be loosely fitted with the hook part  42  is formed on the leg part  34 . Attachment between the upper part of the airbag module  5  and the leg part  34  is not limited to the hook part  42 , and can be done by fixing with a bolt, etc., for example. Also, the lower part of the airbag module  5  is fixed using brackets  45 ,  46  to a vehicle body strength member  44  such as a steering support member provided in the vehicle body. 
     The hinge part  35  connects the door part  32  to the flange part  33  to be able to open and close. With this embodiment, the hinge part  35  has a vehicle front hinge part that connects the first door part and the flange part  33 , and a vehicle rear hinge part that connects the second door part and the flange part  33 . The hinge part  35  has an extra length part  52  that becomes the rotation center of the door part  32 . The extra length part  52  is placed at a position between the door part  32  and the leg part  34  so as to detour downward. The extra length part  52  is approximately a U shape or approximately a V shape in the side view. The hinge part  35  is configured by a hinge member  54  that is formed by a separate member. For the hinge member  54 , it is possible to use a flexible net or film made of resin, or mesh made of metal, etc. With this embodiment, a net made of resin is used for the hinge member  54 . With the hinge member  54 , using insert molding, in a state with the extra length part  52  or its peripheral part exposed in the gap between the door part  32  and the leg part  34  and the flange part  33 , both side parts of the extra length part  52  are buried in the interior of the door part  32  and the flange part  33  or the leg part  34 . 
     For the basic configuration as noted above, with this embodiment, the following kind of configuration is used. 
     Airbag Lid Reinforcing Member  31   
     The airbag lid reinforcing member  31  of this embodiment has: the door part  32  that can open and close; the flange part  33  that surrounds the outer periphery of the door part  32 ; the leg part  34  installed below the flange part  33 ; and the hinge part  35  that connects the door part  32  to the flange part  33  to be able to open and close. 
     Here, the hinge part  35  is constituted by a separate hinge member  54 . In the hinge member  54 , the boundary part with the flange part  33  (or the leg part  34 ) at the opening  61  side is called a root part  35   a . This root part  35   a  is the fulcrum for rotation of the hinge member  54  when the door part  32  opens. 
     (1) As shown in  FIG. 2 , support ribs  151  are provided on the inside surface of the leg part  34  to support the hinge part  35  from the lower surface side (see cross section of the part without ribs in  FIG. 2A ,  FIG. 2B , and  FIG. 3 , and the part with ribs in  FIG. 4 ). In  FIG. 2 , the illustration omits the hook part  42  of the airbag module  5 . 
     A plurality of the support ribs  151  are provided in the width direction of the leg part  34  (vehicle width direction Y) having gaps  152 . 
     Here, the support ribs  151  are inner ribs along the inside surface of the leg part  34 . In  FIG. 4 , the support ribs  151  receive the leg part  34  side part more than the extra length part  52  in the hinge member  54 . For that reason, they are narrow ribs that do not reach the extra length part  52 . 
     There is a risk that if the number of support ribs  151  is small, there may be a burden on the airbag body  4 , so a larger number of the support ribs  151  are provided to a level at which there will not be a burden on the airbag body  4 . Also, when the gaps  152  between the support ribs  151  are too large, the airbag body  4  enters between those support ribs  151 , and contacts the root part  35   a  that is the fulcrum for rotation of the hinge member  54 , so the number is set as appropriate from this perspective as well. On the other hand, the mold may enter the space between the support ribs  151  during molding, so the minimum required dimensions of the gaps  152  depends on the strength of the mold. In  FIG. 2 , the support ribs  151  are provided in a number of approximately 3 times or greater than that of the locking holes  43  provided in the leg part  34 . However, the number of support ribs  151  and the gaps  152  are not limited to what is noted above. 
     Hereafter, the upper edge part of the support ribs  151  is called a support part  153 . In the case of a separate hinge, the lower part in the thickness direction of the hinge part  35  (hinge member  54 ) is buried in the support part  153 . The upper part in the thickness direction of the hinge part  35  is exposed, without being buried in the support part  153 . Also, as shown in  FIG. 12 , during deployment of the airbag body  4 , by opening of the lid section  21 , the lower part in the thickness direction of the hinge part  35  (hinge member  54 ) is peeled from the support part  153 , and the boundary part with an end surface  33   a  of the flange part  33  (or the inner surface of the leg part  34 ) in the hinge member  54  becomes the fulcrum for rotation, and the door part  32  opens. At this time, the hinge part  35  is deformed according to the opening of the lid section  21 , and the support ribs  151  remain in place without deforming. 
     (2) As shown in the modification example of  FIG. 5 , the support part  153  may also be an obtuse angle  154 . 
     The obtuse angle  154  is an angle formed by the inside surface and the upper edge part (support part  153 ) of the support rib  151 . In  FIG. 5 , by using the obtuse angle  154  for the support part  153 , burying inside the leg part  34  is done such that the part supported by the support part  153  of the hinge member  54  becomes an ascending slope facing the flange part  33 , and the part inside the leg part  34  of the hinge member  54  becomes a gentle descending slope facing (the position of the lower surface of) the flange part  33 . 
     The angle formed by the support part  153  and the inside surface of the support rib  151  can be made into a right angle, or can be made into an acute angle as shown in  FIG. 4 . In  FIG. 4 , by using an acute angle for the support part  153 , burying inside the leg part  34  is done such that the part supported by the support part  153  of the hinge member  54  becomes a descending slope facing the flange part  33 , and the part inside the leg part  34  of the hinge member  54  becomes a gentle ascending slope facing (the position of the lower surface of) the flange part  33 . 
     (3) As shown in another modification example in  FIG. 6 , the hinge part  35  has the extra length part  52  detour downward between the door part  32  and the leg part  34 . The support rib  151  may also have an extra length support part  155  that supports the side surface of the leg part  34  side of the extra length part  52 . 
     Here, the extra length support part  155  is formed as a part of the support part  153  at the door part  32  side of the upper edge part (support part  153 ) of the support rib  151 . The extra length support part  155  is a notch of a shape that supports approximately half (half of the side surface and bottom part) of the leg part  34  side of the extra length part  52 . For that reason, the support rib  151  is a wide rib that reaches the position of the bottom part of the extra length part  52 . 
     Mold Device for Manufacturing  101  of Airbag Lid Reinforcing Member  31   
     A mold device for manufacturing  101  of the airbag lid reinforcing member  31  is an item like that shown in  FIG. 7 . The mold device for manufacturing  101  has a molding space  102  for molding the airbag lid reinforcing member  31  like that shown in  FIG. 1  that has the door part  32  that can open and close; the flange part  33  that surrounds the outer periphery of the door part  32 ; the leg part  34  installed below the flange part  33 ; and the hinge part  35  that connects the door part  32  to the flange part  33  to be able to open and close. The molding space  102  is formed on the inside of upper and lower molds  104 ,  103  (upper mold, lower mold). In  FIG. 2B  and  FIG. 8 , a molding space  102   a  molds the flange part  33 , a molding space  102   b  molds the leg part  34 , and a molding space  102   c  molds the door part  32 . Also, in the mold  103 , the location that clamps the hinge member  54  between the molding space  102   a  and the molding space  102   c  is illustrated as a hinge member clamping unit  103   a.    
     Also, as shown in  FIG. 9  (also see  FIG. 2B ), a recess for forming a support rib  156  that molds the support rib  151  is formed having the gap  152  so as to be indented facing the hinge member clamping unit  103   a  from the molding space  102 . 
     As shown in  FIG. 10  (also see  FIG. 5 ), the recess for forming a support rib  156  may also be an item that forms the support part  153  in the obtuse angle  154 . As shown in  FIG. 11  (also see  FIG. 6 ), the recess for forming a support rib  156  may also be an item that forms the extra length support part  155 . 
     In addition to the above, provided in the molds  103 ,  104  are a projection for forming an extra length part  105  for forming the extra length part  52  of the hinge part  35 , and a recess for forming an extra length part  109  (extra length forming part). Also, on the inside of the molds  103 ,  104 , a locate-pin  107  that is inserted in a locate-hole  108  provided on the hinge member  54  for positioning the hinge member  54  is provided as appropriate. 
     Also, as shown in  FIG. 8 , formed in the mold  104  is a hinge member clamping unit  104   a  that grips the hinge member  54  above and below between itself and the hinge member clamping unit  103   a  of the mold  103 . The hinge member clamping unit  103   a  of the mold  103  and the hinge member clamping unit  104   a  of the mold  104  are collectively referred to as a clamping unit  110 . By being formed connected also to the top side of the recess for forming a support rib  156 , the shape of the hinge member clamping unit  104   a  of the upper mold  104  forms the upper edge part (support part  153 ) of the support rib  151 , and also, the lower part in the thickness direction of the hinge part  35  (hinge member  54 ) is buried in the support part  153 , and is used to expose the upper part in the thickness direction of the hinge part  35 . 
     Method for Manufacturing the Airbag Lid Reinforcing Member  31   
     The method for manufacturing the airbag lid reinforcing member  31  manufactures the airbag lid reinforcing member  31  having: the door part  32  that can open and close; the flange part  33  that surrounds the outer periphery of the door part  32 ; the leg part  34  that is installed below the flange part  33 ; and the hinge part  35  that connects the door part  32  to the flange part  33  to be able to open and close. Also, a plurality of support ribs  151  that support the hinge part  35  from the lower surface side having gaps  152  in the width direction of the leg part  34  are formed on the inside surface of the leg part  34 . 
     Here, the airbag lid reinforcing member  31  is manufactured by performing: a step for setting the hinge member  54  on the interior of the opened molds  103 ,  104  (setting step); a step for doing mold clamping of molds  103 ,  104  (mold clamping step); an injection molding step for injecting a molten resin  136  ( FIG. 8 ) inside the molding space  102  (from a gate G ( FIG. 2A ); and a mold removal step for doing mold removal of the airbag lid reinforcing member  31  from the molds  103 ,  104  after the molten resin  136  inside the molding space  102  has hardened to a certain degree. 
     During the setting step, the hinge member  54  is set on the lower mold  103 . 
     At this time, the part positioned on the recess for forming a support rib  156  of the hinge member  54  has the upper part supported by the mold  104 , while the lower part is exposed in the space of the recess for forming a support rib  156 . However, at both sides of this recess for forming a support rib  156  (vehicle width direction Y), the hinge member  54  is in a fixed state by the clamping unit  110 . Similarly, the part that protrudes from the leg part  34  (flange part  33 ) of the hinge member  54  to the door part  32  side (inside) is also gripped and fixed above and below by the clamping unit  110  of the molds  103 ,  104  ( FIG. 8 ), so it cannot move. 
     Also, the part inside the flange part  33  of the hinge member  54  is in a state for which movement is difficult by restraining as appropriate using the locate-pin  107 , etc., in a state set on the lower mold  103 . 
     With the injection molding step, the molten resin  136  is injected inside the molding space  102 . This makes it possible to obtain the airbag lid reinforcing member  31  having the support ribs  151 . At this time, the hinge member  54  positioned on the recess for forming a support rib  156  as noted above is fixed at both sides of the recess for forming a support rib  156  (vehicle width direction Y), so the hinge member  54  creeping into the recess for forming a support rib  156  due to injection pressure is suppressed. The support ribs  151  can also have the support part  153  formed at the obtuse angle  154 , or have the extra length support part  155  provided. 
     Action 
     Following, the action of this embodiment is explained. 
     When the airbag body  4  is deployed and the airbag module  5  comes out during an emergency, the airbag body  4  is guided to follow the leg part  34  while it inflates, and presses the door part  32  and the lid section  21  from below. By this pressing force of the airbag body  4 , the cleavage line  23  is cleaved, the door part  32  and the lid section  21  are opened with the hinge part  35  as the center, and the opening  61  is formed in the lid member  6 . The airbag body  4  expands to the occupant side inside the passenger compartment  2  from this opening  61 , and the upper body of the occupant sitting properly in the seat is protected and restrained. 
     Effect 
     With this embodiment, the following kinds of effects can be obtained. 
     (Effect 1) The support ribs  151  are provided on the inside surface of the leg part  34 . This makes it possible to have the root part  35   a  on the flange part  33  side of the hinge part  35  protected by the support ribs  151 . 
     For that reason, the airbag body  4  is deployed on the interior of the airbag lid reinforcing member  31 , and when guided to follow the leg part  34  while inflating, the airbag body  4  directly rubs the root part  35   a  on the flange part  33  side of the hinge part  35  (the cloth of the airbag body  4  gives shearing force to the hinge part  35 ), and it is possible to prevent damage to the root part  35   a  using the support ribs  151 . 
     Also, a plurality of the support ribs  151  are provided having gaps  152  in the width direction of the leg part  34 . By doing this, the contact part of the airbag body  4  on the support ribs  151  is distributed in a plurality of locations, so it is possible to avoid having the support ribs  151  put a burden on the airbag body  4 . 
     In a case when there are no support ribs  151  in the present embodiment, this kind of damage to the root part  35   a  of the hinge part  35  by the airbag body  4  occurs more easily on the occupant side (rear side) at which the leg part  34  is longer than with the front window side (front side) where the leg part  34  is shorter. This is because when the leg part is short, the airbag body  4  contacts the door part  32  early, so rubbing of the root part  35   a  and the airbag body  4  does not occur easily, and in contrast to this, when the leg part  34  is long, the airbag body  4  contacting the door part  32  and stopping is relatively late, so rubbing of the root part  35   a  and the airbag body  4  occurs easily. 
     Also, at the positions between support ribs  151  (parts without ribs), during molding, the clamping unit  110  of the molds  103 ,  104  grips the part of the hinge part  35  between the support ribs  151  and fixes the position. For that reason, the positional relationship between the root part  35   a  of the hinge part  35  and the support rib  51  is kept in a suitable state. Therefore, the following situations, for example, can be avoided: the position of the hinge part  35  (hinge member  54 ) inside the molds  103 ,  104  being skewed due to the resin pressure (injection pressure) of the molten resin  136 , which may cause the hinge part  35  being pushed into the inside of the support rib  151  and being completely buried in the support rib  151 , and the molten resin  136  entering the top side of the part of the hinge part  35  (root part  35   a ) protruding from the flange part  33 . Accordingly, it is possible for the support ribs  151  to exhibit their original function (function of preventing damage to the hinge part  35 , for example). 
     Actually, with the hinge member  54  not being completely exposed at the end surface  33   a  of the flange part  33 , it is possible for a part of the hinge member  54  to be buried inside the support rib  151  at the flange part  33  side. However, even in this case, it is possible to prevent the complete burial of the hinge member  54  inside the support rib  151 , so it is possible to ensure exposure from the resin of the upper part of the hinge member  54  in the range facing from the tip  151   a  of the support rib  151  to the end surface  33   a  of the flange part  33 . Because of that, the root part  35   a  is positioned further to the outside than the tip  151   a  of the support rib  151  (see  FIG. 4 ,  FIG. 5 , and  FIG. 6 ), and protection of the root part  35   a  is ensured. 
     (Effect 2) The support rib  151  may also use the obtuse angle  154  for the support part  153  with respect to the hinge part  35 . By doing this, when the airbag body  4  is deployed and passes through the position of the apex of the support rib  151  (corner part of the support rib  151  inside edge part and upper edge part (support part  153 )), tearing force input to the airbag body  4  by the apex of the support rib  151  (piercing force on the rib apex by pressure of the airbag body  4  itself) is mitigated, so it is possible to lower the risk of a hole opening in the airbag body  4 . 
     (Effect 3) It is also possible to provide the extra length support part  155  on the support rib  151 . This makes it possible to directly support and fix the side surface of the leg part  34  of the extra length part  52  in a wide range. This makes it possible to always keep the extra length part  52  in a stable state. 
     (Effect 4) With the mold device for manufacturing  101  of the airbag lid reinforcing member  31 , it is possible to obtain the same action and effects as noted above. 
     (Effect 5) With the manufacturing method of the airbag lid reinforcing member  31 , it is possible to obtain the same action and effects as noted above. At this time, a plurality of the support ribs  151  having gaps  152  in the width direction of the leg part  34  are placed at the inside surface of the leg part  34 , and by doing molding to place the root part  35   a  of the hinge part  35  at the position of the apex of the support rib  151 , the hinge part  35  is fixed by being gripped from above and below by the clamping unit  110  of the molds  103 ,  104  at the position where there are no support ribs  151 , so creeping of the hinge part  35  to the inside of the support rib  151  at the position of the support rib  151  (both sides are fixed by gripping by the clamping unit  110  of the molds  103 ,  104 ) is suppressed. 
     EXPLANATION OF CODES 
       4 : Airbag body;  23 : Cleavage line;  31 : Airbag lid reinforcing member;  32 : Door part;  33 : Flange part;  34 : Leg part;  35 : Hinge part;  52 : Extra length part;  54 : Hinge member (net);  101 : Mold device for manufacturing;  103 : Mold (lower mold);  104 : Mold (upper mold);  110 : Clamping unit;  151 : Support rib;  152 : Gap;  153 : Support part;  154 : Obtuse angle;  155 : Extra length support part;  156 : Recess for forming support rib (recess); X: Vehicle front-rear direction; Y: Vehicle width direction; and Z: Vertical direction.