Patent Document

BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a fuel filler port closing apparatus provided with a flapper for opening and closing an opening of a nozzle guide for guiding an fuel filling nozzle inserted from an opening of a filler neck (a fuel filler port), the flapper being pushed and biased upwardly by a torsion coil spring and being rotatable towards the lower side. 
     2. Description of the Related Art 
     A filler neck cap screwed into a filler neck has an advantage of being easy to ensure sealability of the filler neck. However, it has a disadvantage in that the attachment/detachment task of the filler neck cap is cumbersome. There is also a possibility that sealing may be insufficient if a screw-in operation of the cap is inappropriate or that the detached filler neck cap may get lost. Considering these problems, a fuel filler port closing apparatus provided with a flapper is proposed. Such a fuel filler port closing apparatus has the flapper which opens by rotating downwardly (towards the lower side) when pushed by the fuel filling nozzle inserted from the outside and closes by rotating upwardly (towards the upper side) when the fuel filling nozzle is removed. According to the fuel filler port closing apparatus, forgetting to tighten the filler neck cap can not occur. Further, since the filler neck cap is closed immediately before the fuel filling nozzle is inserted and is opened only when the fuel filling nozzle is inserted (i.e., during actual fuel feeding task), discharge of fuel vapor can be suppressed at minimum. 
     The conventional fuel filler port closing apparatus adopts a configuration of opening and closing the opening of the nozzle guide for guiding the fuel filling nozzle inserted from the opening of the filler neck with a rotatable flapper. The flapper is attached so as to be biased upwardly by being pushed by the torsion coil spring and to be rotatable downwardly by being pushed by the fuel filling nozzle. The flapper opens the opening of the nozzle guide when it is pushed by the fuel filling nozzle inserted from the opening of the filler neck and rotated downwardly. When the fuel filling nozzle is removed, the flapper rotates upwardly by the torsion coil spring thereby closing the opening of the nozzle guide. Such a fuel filler port closing apparatus has a problem in that it is difficult to realize the processing accuracy of the flapper and the opening of the nozzle guide, and the assembly accuracy of the flapper and the nozzle guide as designed. Furthermore, since the amount of deflection of the seal packing attached to the flapper varies, the necessary sealability of the filler neck may become difficult to ensure. 
     JP 2007-331518 discloses a fuel filler port closing apparatus in which the bias of the flapper is made sufficiently strong while reducing the spring constant of each torsion coil spring and accommodating the bending stress in time of closure within the allowable level by forming the torsion coil spring as a double configuration. The fuel filler port closing apparatus of JP 2007-331518 ensures the sealability of the filler neck by strongly pressing the seal packing attached to the flapper against the peripheral edge (valve seat) of the opening of the nozzle guide. 
     U.S. Pat. No. 5,732,840 and U.S. Pat. No. 6,446,826 disclose a configuration in which a bearing hole of the rotation shaft of the flapper is formed as a long hole and the flapper is pressed and moved parallel with respect to the opening of the nozzle guide. The seal packing attached to the flapper then can be reliably pressed against the peripheral edge (valve seat) of the opening of the guide to ensure the sealability of the filler neck. 
     The fuel filler port closing apparatus disclosed in U.S. Pat. No. 5,732,840 and U.S. Pat. No. 6,446,826 excels in that the seal packing attached to the flapper is reliably pressed against the peripheral edge (valve seat) of the opening of the nozzle guide to ensure the sealability of the filler neck by simply forming the bearing hole of the rotation shaft of the flapper as a long hole. 
     In other words, the fuel filler port closing apparatus disclosed in U.S. Pat. No. 5,732,840 and U.S. Pat. No. 6,446,826 change the orientation of the flapper within the range of the vertically long hole in the peripheral direction to evenly press the seal packing against the peripheral edge (valve seat) of the opening of the nozzle guide while absorbing the variation in the amount of deflection. If the seal packing can be evenly pressed against the peripheral edge (valve seat) of the guide opening in the peripheral direction, the lowering in the processing accuracy of the flapper and the opening of the nozzle guide and the assembly accuracy of the flapper and the nozzle guide can be absorbed. 
     However, if the bearing hole is a long hole, the flapper may not smoothly rotate. For instance, as seen from  FIG. 8 , in a tilted orientation in which one end of the rotation shaft  601  is positioned at the upper end edge of one bearing hole  602  and the other end of the rotation shaft  601  is at the lower end edge of the other bearing hole  602 , the rotation of the flapper  603  is inhibited by the mutual friction of bearing flanges since the bearing flange  604  of the flapper that passes the rotation shaft  601  therethrough tilts with respect to the bearing flange  605  of the nozzle guide. Flapper is thought to be easily tilted by pushed on its peripheral end with the fuel filling nozzle. In the worst case, the flapper  603  might be get caught between the flanges  605  in the state illustrated in  FIG. 8 . Furthermore, since the torsion coil spring  606  is normally attached to the rotation shaft  601 , the bearing flange  604  of the tilted flapper may inhibit the movement of the torsion coil spring  606 . 
     SUMMARY OF THE INVENTION 
     The present invention aims to provide a fuel filler port closing apparatus capable of evenly and reliably pressing, in the peripheral direction, a seal packing against the peripheral edge (valve seat) of an opening of an nozzle guide without forming a bearing hole for a rotation shaft of a flapper as a long hole, which has a problem in reliability. 
     The above problem with the conventional fuel filler port closing apparatus is solved by a fuel filler port closing apparatus of the present invention provided with a flapper, which closes an opening of a nozzle guide by being pushed and biased upwardly by a torsion coil spring, and pushed downwardly and opened with an fuel filling nozzle inserted through an opening of a filler neck up to the opening of the nozzle guide; wherein the flapper is configured by a rotation plate which is pushed and biased upwardly by the torsion coil spring and which is rotated downwardly by being pushed with the fuel filling nozzle, and a seal plate holding a seal packing pressed against a peripheral edge of the opening of the nozzle guide; and the seal plate is coupled to an upper surface side of the rotation plate so as to be freely displaceable in an up and down direction with respect to the rotation plate. 
     The flapper of the fuel filler port closing apparatus of the present invention is configured by a rotation plate which is pushed and biased upwardly by the torsion coil spring and which is rotatable downwardly, and a seal plate holding a seal packing to be pressed against a peripheral edge of the opening of the nozzle guide. The flapper presses the seal packing against the peripheral edge (valve seat) of the opening of the nozzle guide while absorbing the variation of deflection by changing the orientation of the seal plate with respect to the rotation plate. 
     In the fuel filler port closing apparatus of the present invention, the seal plate does not tilt in an abnormal direction with respect to the peripheral edge (valve seat) of the opening of the nozzle guide since the seal plate is coupled to be freely displaceable in the up and down direction with respect to the rotation plate on the upper surface side of the rotation plate. That is, according to the present invention, the seal packing can be evenly pressed against the peripheral edge (valve seat) of the guide opening in the peripheral direction. When referring to “evenly pressing against in the peripheral direction”, this does not refer to a state in which the pressing force is always even in the peripheral direction but refers to a state in which the physical contact in the peripheral direction is even and the sealability in the peripheral direction is sufficiently exhibited. 
     The configuration for regulating the displacement direction of the seal plate is as follows. The seal plate has a coupling projection, which has the same cross-sectional shape as a coupling hole formed in the rotation plate, projecting out from a lower surface. The coupling projection is inserted to the coupling hole from above, the coupling projection is projected out from the coupling hole with the lower surface of the seal plate surface contacted to the upper surface of the rotation plate, and an engagement portion is formed at the portion of the coupling projection at a position spaced apart from the lower surface of the rotation plate. Since the coupling hole and the coupling projection closely engage other than in the up and down direction with respect to the rotation plate, the seal plate does not tilt in an abnormal direction (lateral direction). The engagement portion formed at the coupling projection is formed, for example, by melting and solidifying the distal end of the coupling projection, as the seal plate is normally made of resin. 
     The torsion coil spring may engage one end to the rotation plate attached to the nozzle guide by way of the rotation shaft, and may indirectly press the seal plate against the peripheral edge (valve seat) of the opening of the nozzle guide by way of the rotation plate that is biased upwardly. However, in order to securely press the seal packing against the peripheral edge (valve seat) of the opening of the nozzle guide, the torsion coil spring preferably directly biases the seal plate. In other words, a pushing projection of the seal plate is inserted to a through-hole formed in the rotation plate from above, and the pushing projection is projected out from the lower surface. The seal plate can be directly biased by engaging the biased one end of the coil spring to the pushing projection. The seal plate is then directly biased by the torsion coil spring while having the rotating direction regulated by the rotation plate, and the seal packing can be reliably pressed against the peripheral edge (valve seat) of the guide opening. 
     According to the present invention, a fuel filler port closing apparatus capable of stably and reliably pressing the seal packing against the peripheral edge (valve seat) of the opening of the nozzle guide evenly in the peripheral direction is provided. This effect is obtained as the flapper of the fuel filler port closing apparatus is divided to the rotation plate and the seal plate, and the seal plate is freely displaceable only in the up and down direction with respect to the rotation plate. Furthermore, the regulation in the displacement direction of the seal plate is realized by inserting the coupling projection of the seal plate to the coupling hole of the rotation plate having the same cross-sectional shape. The seal packing can be reliably pressed against the peripheral edge (valve seat) of the guide opening by engaging one end of the torsion coil spring to the pushing projection of the seal plate projected out from the through-hole of the rotation plate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating an example of a flapper of the present invention; 
         FIG. 2  is an exploded perspective view of the flapper of the present example; 
         FIG. 3  is a perspective view corresponding to  FIG. 1  illustrating another example of the flapper of the present invention; 
         FIG. 4  is a cross-sectional view of a fuel filler port closing apparatus using the flapper of the present example; 
         FIG. 5  is a partially enlarged cross-sectional view of the fuel filler port closing apparatus illustrating a normal state in which the flapper closes a opening of a nozzle guide; 
         FIG. 6  is a partially enlarged cross-sectional view corresponding to  FIG. 5  of the fuel filler port closing apparatus illustrating a state in which a seal packing is deflected thereby forming a gap Δ; and 
         FIG. 7  is a partially enlarged cross-sectional view corresponding to  FIG. 5  of the fuel filler port closing apparatus illustrating a state in which a seal plate is pushed up thereby filling the gap Δ. 
         FIG. 8  is a pattern diagram illustrating a tilted flapper of a conventional fuel filler port closing apparatus. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The preferred embodiments for implementing the present invention will be described with reference to the drawings.  FIG. 1  is a perspective view illustrating an example of a flapper  3 .  FIG. 2  is an exploded perspective view of the flapper  3  of the present example.  FIG. 3  is a perspective view corresponding to  FIG. 1  illustrating another example of the flapper  3  of the present invention.  FIG. 4  is a cross-sectional view of a fuel filler port closing apparatus using the flapper  3  of the present example.  FIG. 5  is a partially enlarged cross-sectional view of the fuel filler port closing apparatus illustrating a normal state in which the flapper  3  closes an opening  211  of a nozzle guide.  FIG. 6  is a partially enlarged cross-sectional view corresponding to  FIG. 5  of the fuel filler port closing apparatus illustrating a state in which a seal packing  325  is deflected thereby forming a gap Δ.  FIG. 7  is a partially enlarged cross-sectional view corresponding to  FIG. 5  of the fuel filler port closing apparatus illustrating a state in which a seal plate  32  is pushed up thereby filling the gap Δ.  FIG. 8  is a pattern diagram illustrating the state that a flapper  603  of a prior arts tilts. 
     The fuel filler port closing apparatus of the present invention has a characteristic flapper  3  for opening and closing an opening  211  of a nozzle guide  21 . The flapper  3  of the present example is configured by a rotation plate  31 , which is pushed and biased upwardly by a torsion coil spring  314  and which is rotatable downwardly; and a seal plate  32  holding the seal packing  325  pressed against the peripheral edge of the opening  211  of the nozzle guide  21 . The seal plate  32  is coupled so as to be freely displaceable in an up and down direction with respect to the rotation plate  31  on the upper surface side of the rotation plate  31  (see  FIG. 4 ). The entire configuration of the flapper  3  is not greatly different from the conventionally known fuel filler port closing apparatus of the same type in size and in positional relationship of a rotation shaft  317  other than that the flapper  3  is divided to the rotation plate  31  and the seal plate  32 . This means that the flapper  3  of the present invention can be easily applied to the conventionally known fuel filler port closing apparatus of the same type. 
     As illustrated in  FIGS. 1 and 2 , the flapper  3  of the present example is configured by the rotation plate  31 , the seal plate  32 , and a packing holding plate  33 . The rotation plate  31  is a metal plate having a circular shape in the front and square shape in the back, formed with one-through hole  312  of square shape in plane view at the middle, and one connection hole  311  of circular shape in plane view at the front and back of the through-hole  312 . The rotation plate  31  has a pair of left and right arms  318 ,  318  projecting out from both sides towards the back side, and the rotation shaft  317  passed through an axial-attachment plate  313  arranged at each arm  318 . The torsion coil spring  314  is freely fitted to the rotation shaft  317 , and is positionally-fixed by pressing a one end  316  against the inner surface of a closure unit  2  (see  FIG. 4 ). Other end  315  of the torsion coil spring  314  is pressed against a pushing projection  323  of the seal plate  32  projecting out from the through-hole  312  of the rotation plate  31  to directly push the seal plate  32  upwardly. 
     The seal plate  32  is a resin plate having a circular shape in plan view for mounting the seal packing  325  having an outer diameter corresponding to the peripheral edge (valve seat)  212  of the opening  211  of the nozzle guide  21  (see  FIG. 4 ). The seal plate  32  of the present example has the pushing projection  323 , having a square cross-section equal to the planar shape of the through-hole  312 , projecting out at the middle on the lower surface side. The seal plate  32  also has coupling projections  321  of circular cross-section equal to the planar shape of the coupling holes  311  projecting out from the position on the lower surface side corresponding to the coupling holes  311  with the pushing projection  323  in between. Furthermore, the seal plate  32  has an assembly flange  326  projecting out on the upper surface side. The pushing projection  323  is used to push up the seal plate  32  by the torsion coil spring  314 . The coupling projections  321  are used to couple the rotation plate  31  and the seal plate  32 . The assembly flange  326  is used to assemble the packing holding plate  33 , a cover plate  331  ( FIGS. 1 and 2 ), and a roller  332  ( FIG. 3 ). 
     The seal plate  32  inserts the two coupling projections  321  to the two corresponding coupling holes  311  formed in the rotation plate  31 , respectively, and projects the coupling projections  321  out from the coupling holes  311  with the lower surface of the seal plate  32  surface contacted to the upper surface of the rotation plate  31 . The seal plate  32  can be coupled so as to be freely displaceable in the up and down direction with respect to the rotation plate  31  by arranging an engagement portion  322  at the portion of the coupling projection  321  at the position spaced apart from the lower surface of the rotation plate  31 . The engagement portion  322  is formed by melting and solidifying the distal end of the coupling projection  321 . The coupling projection  321  has the same cross-sectional shape (circular cross-section) as the coupling hole  311 , and thus the coupling hole  311  and the coupling projection  321  closely engage other than in the up and down direction with respect to the rotation plate  31 , and do not tilt in an abnormal direction. The seal plate  32  thus displaces only in the up and down direction with respect to the rotation plate  31  within a range in which the engagement portion  322  engages the lower surface of the rotation plate  31 , and fills the gap Δ formed between the valve sheet and the seal packing  325 . 
     In the flapper  3  of the present invention, the rotation plate  31  follows a motion of the seal plate  32  by the engagement of the coupling hole  311  the coupling projection  321  pushed up by the torsion coil spring  314 . Specifically, the seal plate  32  projects the pushing projection  323  of square cross section out at the middle of the lower surface, and engages one end  315  of the torsion coil spring  314  in an engagement groove  324  extending in the left and right direction formed at the distal end. Therefore, the rotation plate  31  functions only as a member for displacing the seal plate  32  that actually opens and closes the opening  211  of the nozzle guide along a circular arc path having the rotation shaft  317  as the center. 
     The seal packing  325  is a circular ring elastic material made of rubber having a protrusion of triangular cross-section on the outer periphery. The seal packing  325  is sandwiched and held by a peripheral edge portion of the upper surface of the seal plate  32  and the lower surface of the packing holding plate  33  to be connected to the seal plate  32 . Specifically, the seal packing  325  is mounted on two concentric supporting protrusions formed at the peripheral edge portion of the upper surface of the seal plate  32 . The cylindrical main body of the packing holding plate  33  is then fitted to the inner peripheral edge of the seal packing  325 , and the seal packing  325  is held with the lower surface of the radially and outwardly projecting flange of the holding plate  33  (see  FIG. 5  and subsequent figures). 
     The holding plate  33  is coupled to the seal plate  32  by projecting the assembly flange  326  of the seal plate  32  out from an assembly hole  336  of the holding plate  33 , communicating an attachment hole  327  of the assembly flange  326  and coupling holes  334  of the holding plate  33  and inserting a coupling pin  333 . The holding plate  33  of the present example includes a metal cover plate  331  having a hill-shaped cross-section at the middle of the upper surface. The cover plate  331  prevents the fuel filling nozzle (not shown) from getting caught at the flapper  3  when pulling out the fuel filling nozzle (not shown) having the side surface contacted to the push-opened flapper  3 . The cover plate  331  protects the holding plate  33  made of resin. The cover plate  331  of the present example is fixed by communicating the attachment hole  327  of the assembly flange  326 , the coupling holes  334  and the attachment hole  335  of the holding plate  33  and inserting the coupling pin  333 . 
     In order to prevent the fuel filling nozzle being pulled out from being caught at the flapper  3 , a roller  332  may be attached to the holding plate  33  in addition to the cover plate  331 , as illustrated in  FIG. 3 . The roller  332  of another example is attached to the holding plate  33  by communicating the assembly hole of the assembly flange  326 , the coupling hole  334  of the holding plate  33 , and a roller shaft hole (not shown), and inserting the coupling pin  333 . The cover plate  331  is positionally fixed by inserting the coupling pin  333  to an assembly piece (not shown) extended between the assembly flange  326  and the roller  332 . When a finger (not shown) is caught at the opening  211  of the nozzle guide by mistake, the roller  332  added to the cover plate  331  allows the finger to be easily removed. 
     The overall configuration of the fuel filler port closing apparatus assembled with the flapper  3  of the present invention will be described hereinafter. As shown in  FIG. 4 , the fuel filler port closing apparatus of the present example is configured by a filler neck  1 , a closure unit  2 , and a cover unit  4 . The closure unit  2  is attached with the flapper  3 , which is pushed down by the fuel filling nozzle (not shown) inserted from the opening  44  of the filler neck of the cover unit  4  thereby opening the opening  211  of the nozzle guide. An upwardly rotatable cover  5  is attached to the cover unit  4 , where the opening  44  of the filler neck is opened and closed by the cover  5 . The cover unit  4  is also fixed with an attachment plate  56  attached with a rotation shaft  511  of a cover main body  51 . 
     The filler neck  1  is a tubular member made of metal in which an opening at the upper end is wide and a connection port  11 , which is an opening at the lower end, narrows in accordance with a fuel feeding tube main body  8  to be connected. The filler neck  1  of the present example is a separate body from the fuel feeding tube main body  8 , but the end of the fuel feeding tube main body  8  may be enlarged to configure the filler neck  1 . The closure unit  2  is a resin block formed with the nozzle guide  21  for guiding the fuel filling nozzle (not shown) inserted from the opening  44  of the filler neck. The flapper  3  for opening and closing the opening  211  is integrally assembled to the closure unit  2 . A ring-shaped fit-in groove  221  is formed at a peripheral surface  22  of the closure unit  2  of the present example. A seal ring  222  is fitted into the ring-shaped fit-in groove  221  to ensure the sealability when the closure unit  2  is fitted into the filler neck  1 . 
     The cover  5  opens and closes the opening  44  of the filler neck positioned at the upper stage of the opening  211  of the nozzle guide to prevent rainwater and dust from accumulating at the opening  211  of the nozzle guide. The cover main body  51  of the cover  5  of the present example is attached to the rotation shaft  511  supported by the attachment plate  56 . The cover main body  51  is biased in an opening direction by the torsion coil spring  512 , and maintains the opening  44  in the closed state by engaging a latch  531  provided on the cover main body  51  to the opening  44  of the filler neck. Furthermore, the fuel filler port closing apparatus of the present example has a spacer  6  interposed between the closure unit  2  and the cover unit  4 . The spacer  6  is formed with an opening  61  for fixing the inserted nozzle. The opening  61  is one size smaller than the opening at the upper end of the nozzle guide  21  to engage and hold the inserted fuel filling nozzle. 
     As illustrated in  FIG. 5 , according to the flapper  3  of the present invention, the seal plate  32  pushed up by the torsion coil spring  314  closes the opening  211  of the nozzle guide by evenly pressing the seal packing  325  against the peripheral edge (valve seat)  212  of the opening  211  in the peripheral direction. The seal packing  325  is pressed against the peripheral edge (valve seat)  212  of the opening  211  by the seal plate  32 . The seal plate  32  is directly pushed up by the one end  315  of the torsion coil spring  314 . As long as the seal packing  325  does not deflect, the seal packing  325  is evenly pressed against the peripheral edge (valve seat)  212  of the opening  211  in the peripheral direction even if the rotation plate  31  is tilted, whereby reliable sealability is achieved. 
     However, when the seal packing  325  is deflected thereby forming a gap Δ at one part, as illustrated in  FIG. 6 , the seal plate  32  is pushed up in a range where the engagement portion  322  of the coupling projection  321  engages the lower surface of the rotation plate  31 . As a result, the seal packing  325  is again evenly pressed against the peripheral edge (valve seat)  212  of the opening  211  of the nozzle guide, as illustrated in  FIG. 7 , whereby reliable sealability is achieved. 
     The flapper  3  of the present invention allows the seal plate  32  holding the seal packing  325  to be displaceable only in the up and down direction with respect to the rotation plate  31 . Therefore, even if the gap Δ is formed, the sealability is not affected as the seal plate  32  tilts and deforms the seal packing  325 . The flapper  3  of the present invention thus suppresses the formation of the gap Δ, and exhibits stable and reliable sealability. 
     EXAMPLES 
     In order to assess an effect of the present invention, a sealability of a fuel filler port closing apparatus equipped with the flapper of the present invention and that of a fuel filler port closing apparatus equipped with a conventional flapper (hereinafter referred to as a “comparison”) were measured. As the comparison, the fuel filler port closing apparatus having a flapper made of a single plate and a long bearing hole for a rotation shaft of the flapper was used. Configuration of the present invention and the comparison was summarized in table 1. 
     
       
         
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Present 
                   
               
               
                   
                 invention 
                 Comparison 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Diameter of the seal 
                 31 
                 31 
               
               
                   
                 packing (mm) 
               
               
                   
                 Spring load (N) 
                 12 
                 12 
               
               
                   
                 Shape of bearing hole 
                 Circle 
                 Vertically long 
               
               
                   
                   
               
             
          
         
       
     
     The connection port  11  of the fuel filler port closing apparatuses of present invention and comparison were connected to a suction pump and were aspirated. The pressure (kPa) at which the amount of gas leak (cc) per minute reached to 3 cc/min were measured. The measurement was conducted plural times. The results were summarized in the table 2. According to the present invention the pressure were around −10 kPa to −12 kPa and were stable. Contrast to this, according to the comparison, the pressure were unstable and gas leaking began around −3 kPa to −5 kPa. 
     
       
         
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Present 
                   
               
               
                   
                 Invention 
                 Comparison 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Pressure 
                 −10 to −12 
                 −3 to −5 
               
               
                   
                 (kPa)

Technology Category: b