An open-close portion structure of a vehicle body includes: an open-close member which opens and closes an opening of the vehicle body; a first hinge member provided on the vehicle body; a second hinge member provided on the open-close member, being pivoted with the first hinge member; and a stretchable stay provided between the vehicle body and the open-close member and biasing the open-close member to open, wherein an end of the stretchable stay is coupled to the second hinge member.

BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a structure of an open-close portion of a vehicle body such as a tailgate which opens and closes an opening of a vehicle body.  
         [0003]     Priority is claimed on Japanese Patent Application No. 2005-316554, filed Oct. 31, 2005, the content of which is incorporated herein by reference.  
         [0004]     2. Description of the Related Art  
         [0005]     Vehicles such as station wagons and vans have a flip-up tailgate. These vehicles are adapted to load and unload from its opening at the backside by lifting the tailgate (see, for example, Japanese Unexamined Patent Application, First Publication No. 2005-75210).  
         [0006]     The tailgate is mounted on the top end of the opening by a hinge which is rotatable, and a stretchable stay is provided between the vehicle body and the tailgate. The stay is provided for making opening of the tailgate easier and for keeping the tailgate open. The stay usually includes a gas spring having a damper function, and biases the tailgate to open by the pressure of the filler gas.  
         [0007]     The hinge has a constitution of a vehicle body hinge member and a tailgate hinge member being pivoted by a hinge pin. The vehicle body hinge member is provided in a groove extending along a joining portion of a roof panel and a side panel of the vehicle body. This is to enable the tailgate to open at a large degree without interference with the back end of the roof panel.  
         [0008]     However, the hinge and the stay have to be mounted separately in these conventional open-close portion structures. This increases the number of components of the structure and makes the mounting operation more complex. That is, the tailgate hinge member is mounted on the upper end of the side of the tailgate, and a bracket for mounting the stay is mounted on the side of the tailgate, being away from the tailgate hinge member. This has been a cause of the increase of components and the complexity of the mounting operation.  
       SUMMARY OF THE INVENTION  
       [0009]     An object of the present invention is to provide a structure of an open-close portion of a vehicle body, the structure of which can reduce the number of components required and is easy to attach, by mounting a hinge and a stretchable stay on an open-close member via a common member.  
         [0010]     A first aspect of the present invention is an open-close portion structure of a vehicle body including: an open-close member which opens and closes an opening of the vehicle body; a first hinge member provided on the vehicle body; a second hinge member provided on the open-close member, being pivoted with the first hinge member; and a stretchable stay provided between the vehicle body and the open-close member and biasing the open-close member to open, wherein an end of the stretchable stay is coupled to the second hinge member.  
         [0011]     Due to the aforementioned constitution, an end of the stretchable stay is mounted on the open-close member via the second hinge member mounted on the open-close member. It becomes easier to set the point on which the load from the stretchable stay is applied near the rotational center of the open-close member, and the second hinge member prevents the deformation of the open-close member due to the load applied by the stretchable stay.  
         [0012]     The second hinge member may be made of a plate member and provided on a side surface of the open-close member which is perpendicular to a rotation axis of the open-close member.  
         [0013]     In this case, in at least a portion of the second hinge member which covers the open-close member, the load from the stretchable stay is applied from a direction perpendicular to the thickness of the second hinge member.  
         [0014]     A second aspect of the present invention is an open-close portion structure of a vehicle body having a roof panel and a side panel including: a tailgate which opens and closes an opening of the vehicle body; a first hinge member provided in a groove extending along a joint portion of the roof panel and the side panel; a second hinge member provided on the tailgate, being pivoted with the first hinge member; and a stretchable stay provided between the vehicle body and the tailgate, biasing the tailgate to open, wherein an end of the stretchable stay is coupled to the second hinge member.  
         [0015]     Due to the aforementioned constitution, an end of the stretchable stay is mounted on the tailgate via the second hinge member mounted on the tailgate. It becomes easier to set the point on which the load from the stretchable stay is applied near the rotational center of the tailgate, and the second hinge member prevents the deformation of the tailgate due to the load applied by the stretchable stay. In addition, since the first hinge member is mounted on the groove provided at both ends of the roof of the vehicle body, the stretchable stay can be mounted sufficiently near the side wall of the opening of the vehicle body.  
         [0016]     The second hinge member may be made of a plate member and provided on a side surface of the tailgate which is perpendicular to a rotation axis of the tailgate.  
         [0017]     In this case, in at least a portion of the second hinge member which covers the tailgate, the load from the stretchable stay is applied from a direction perpendicular to the thickness of the second hinge member.  
         [0018]     The second hinge member may have a strip portion which extends to a position away from the side surface, and the end of the stretchable stay may be coupled to the strip portion. In this case, the mounting position of the stretchable stay is not restricted by the tailgate.  
         [0019]     The second hinge member may have a step portion which bends toward the inside of the opening, and the strip portion may extend from the step portion.  
         [0020]     In this case, the side of the tailgate on which the second hinge member is mounted can be offset in the width direction of the vehicle body to the portion of the second hinge member on which the stretchable stay is mounted.  
         [0021]     The second hinge member may have an extended portion which extends on the side surface, and the end of the stretchable stay may be coupled to the extended portion. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]      FIG. 1  is an exploded perspective view of a backside of a vehicle according to the first embodiment of the present invention.  
         [0023]      FIG. 2  is an enlarged perspective view of the portion A in  FIG. 1 .  
         [0024]      FIG. 3  is a cross sectional view along line B-B in  FIG. 2 .  
         [0025]      FIG. 4  is an enlarged perspective view of a member used in another embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0026]     An embodiment of the present invention shall be described with reference to FIGS.  1  to  3 . In the following description, terms “front” and “rear” respectively indicate front and rear in a traveling direction of a vehicle, and terms “upper” and “lower” respectively indicate upper and lower in the vertical direction, unless a different definition is presented.  
         [0027]     A vehicle  1  shown in  FIG. 1  is a station wagon having a tailgate  2  (an open-close member) on the rear portion thereof. The tailgate  2  is mounted rotatably in the vertical direction on an opening  3  provided at the backside of the vehicle  1 . A back end of a roof portion of the vehicle  1  functions as a rotational axis of the tailgate  2 . A baggage space  4  is provided in the cabin near the opening  3 , and is adapted to be loaded and unloaded by opening the tailgate  2 .  
         [0028]     In the roof portion of the vehicle  1 , top ends of side panels  6  which constitute side surfaces of the vehicle  1  are spot welded to both ends of a roof panel  5  disposed at the center in the width of the vehicle  1 . The ends of the roof panel  5  and the side panels  6  which are welded to each other are bent to form a crank. Therefore, grooves  7  having a U-shaped cross section are formed along the longitudinal direction of the vehicle  1  after the roof panel  5  and the side panels  6  are welded. The grooves  7  are formed on the right and left ends of the roof portion.  
         [0029]     The width of each groove  7  gradually increases toward the back end of the vehicle body. A hinge  8  is mounted on the bottom of a portion of the groove  7  which has a greater width, and rotatably supports the tailgate  2 .  
         [0030]     A roof molding  9  is mounted on each groove  7 , and a hinge molding  10  which covers the hinge  8  is integrally formed at the back end of the roof molding  9 .  
         [0031]     A window  11  is formed in the upper half of the tailgate  2 , and a tailgate glass  35  is mounted on the window  11 . The tailgate  2  is constituted by integrating an outer panel  12  and an inner panel  13  by a hemming process. The edge of the outer panel  12  is folded on the inner panel  13 , and the inner panel  13  bulges from the portion where the outer panel  12  is folded to the cabin side. The bulge of the inner panel  13  constitutes the thickness of the tailgate  2 .  
         [0032]     In other words, side surfaces  14  of the tailgate  2  are formed by the bulge of the inner panel  13  and are located inside from the edge of the outer panel  12  in the width direction by the length of the hemming process. The side surfaces  14  extend to be perpendicular to the rotational axis of the tailgate  2 . The rotation of the tailgate  2  is indicated by arrows C and D shown in  FIG. 1 .  
         [0033]     The hinge  8  for mounting the tailgate  2  on the vehicle body includes a first hinge member  15  and a second hinge member  16 . The first hinge member  15  is mounted on the bottom of the groove  7 , at the back end thereof, and the second hinge member  16  is mounted on the side surface  14 , near the top end of the tailgate  2 . The first hinge member  15  and the second hinge member  16  are pivoted by a hinge pin  17 .  
         [0034]     The first hinge member  15  is made of a metal plate member having an L-shaped cross section and has a base portion  18  and a support strip portion  19 . The base portion  18  is mounted on the bottom of the groove  7  by a bolt, and the support strip portion  19  is formed at the rear end of the base portion to protrude upward. The first hinge member  15  and the second hinge member  16  are coupled at the support strip portion  19  via the hinge pin  17 .  
         [0035]     The second hinge member  16  is made of a metal plate member and has a base portion  20 , a coupling portion  21 , and a strip portion  22 . The base portion  20  is mounted on the side surface  14  by a bolt. The coupling portion  21  extends from an end of the base portion  20  toward the upper front of the tailgate  2  and substantially parallel to the side surface  14 , and forms an approximately L-shape with the base portion  20 . The strip portion  22  extends from the base portion  20  toward the cabin side of the tailgate  2 . The second hinge member  16  and the first hinge member  15  are coupled at the front end of the coupling portion  21  (an aperture  21   a  shown in  FIG. 2 ) via the hinge pin  17 . The base portion  20  and the coupling portion  21  are made almost plane, and a step portion  23  is provided between the base portion  20  and the strip portion  22  as shown in  FIG. 3 . This step portion  23  extends from the side surface  14  near a window frame  24  of the tailgate  2  over a backside  25  of the window frame  24 . Therefore, the strip portion  22  extends at a position which is offset to the side surface  14  and nearer the center of the vehicle  1  in the width direction.  
         [0036]     The base portion  20  is mounted on the side surface  14  of the tailgate  2  (the inner panel  13 ) by a bolt  26 , and a stiffener  27  for increasing the support strength of the second hinge member  16  is joined on the other side of the portion of the inner panel  13  on which the base portion  20  is mounted. Reference numeral  28  in  FIG. 2  indicates a U-shaped groove for drainage formed at approximately the center of the base portion  20  in its longitudinal direction.  
         [0037]     A pin  29  protruding outside in the width direction of the vehicle body is provided on the strip portion  22  of the second hinge member  16 , and a first end  31  of a stretchable stay  30  (hereinafter, simply referred to as “stay”) for supporting the tailgate is rotatably coupled to the pin  29 . The stay  30  has a gas spring having a damper function and a second end  32  of the stay  30  is rotatably coupled to the side edge of the opening  3  of the vehicle body. The stay  30  biases the tailgate  2  to open by the pressure of the filler gas of the gas spring. Though only the stay  30  on the left side of the tailgate  2  is shown in  FIG. 1 , another stay  30  is also mounted on the right side of the tailgate  2  in the same manner.  
         [0038]     Since the first end  31  of the stay  30  is coupled to the second hinge member  16 , the number of components can be reduced and make the mounting operation easier than that of the conventional structure, in which a bracket is mounted on the tailgate  2  and the stay  30  is coupled to the tailgate  2  via the bracket. Therefore, manufacturing cost can be saved by the present structure.  
         [0039]     In addition, since a portion to be coupled with the stay  30  is integrally provided in the second hinge member  16 , it can be easier to set a point on which the load from the stay  30  is applied near the rotational center of the tailgate  2 . Therefore, it can be possible to constitute a structure in which the load applied from the stay does not work as a great bending moment to the open-close member. Furthermore, the tailgate  2  can be reinforced by the second hinge member  16  so as to prevent the deformation of the tailgate  2  due to the load applied by the stay  30 . Since the tailgate is not bent by the bias of the stay  30  in the present structure, fitting adjustment of the tailgate  2  can be reduced.  
         [0040]     In the present embodiment, the strip portion  22  for coupling the stay  30  extends from the base portion  20  toward the cabin side of the tailgate  2 . Therefore, the deformation of the tailgate  2  is more effectively prevented by setting the mounting portion of the stay  30  closer to the rotational center of the tailgate  2 .  
         [0041]     Since the portion for coupling the stay  30  is integrated with the second hinge member  16  in the present structure, the area of the stiffener  27  for reinforcing the inner panel  13  of the tailgate  2  can be reduced.  
         [0042]     In the present structure around the tailgate  2  of the vehicle, the base portion  20  of the second hinge member  16  made of a plate member is connected to the side surface  14  of the tailgate  2  which is perpendicular to the rotational axis of the tailgate  2 . Since the load from the stay  30  is applied on the connecting area of the second hinge member  16  and the tailgate  2  from the direction which is perpendicular to the thickness of the second hinge member  16 , the second hinge member  16  can receive the load from the stay  30  from a direction to which the second hinge member  16  has a greater strength. The load from the stay  30  is applied from a shearing direction at the coupling portion of the second hinge member  16  and the tailgate  2 .  
         [0043]     In the present embodiment, the first hinge member  15  is mounted in the groove  7  on the right-and-left side of the roof of the vehicle body, and the first end  31  of the stay  30  is coupled to the second hinge member  16  which is supported by the first hinge member  15 . Therefore, the stay  30  can be disposed sufficiently near the right-and-left side edge of the opening  3  of the vehicle body. As a result, the stay  30  does not obstruct the loading and unloading from the opening  3 , and the space of the opening  3  of the vehicle body can be sufficiently maintained.  
         [0044]     In this embodiment, since the strip portion  22  extends from the base portion  20  of the second hinge member  16  toward the cabin side of the tailgate  2  and the first end  31  of the stay  30  is coupled to the strip portion  22 , the mounting position of the stay  30  is not restricted by the side surface  14  of the tailgate  2 . Therefore, the layout flexibility of the stay can be improved.  
         [0045]     Furthermore, since the step portion  23  is provided on the base portion  20  of the second hinge member  16  over the side surface  14  and the backside  25  and the strip portion  22  extends from the step portion  23 , the first end of the  31  of the stay  30  is disposed at a position which is offset to the side surface  14  of the tailgate  2  and nearer the center of the vehicle  1  in the width direction. The window frame  24  of the tailgate  2  thus can be disposed closer to the side wall of the vehicle body without reducing the cross section of the window frame  24 .  
         [0046]     While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit or scope of the present invention. For example, though the strip portion  22  extending toward the cabin side of the tailgate  2  is integrally provided on the base portion  20  of the second hinge member  16  in the present embodiment, the base portion  20  may be extended along the side surface  14  of the tailgate  2  (an extended portion  33 ) instead of providing the strip portion  22 . In this case, a coupling portion for coupling the stay  30  is provided in the extended portion  33  of the base portion  20 .  
         [0047]     Accordingly, the invention is not to be considered as being limited by the foregoing description, and is only limited by the scope of the appended claims.