Abstract:
A seal with an integral base material in which a gasket is formed integrally with a film, sheet, or plate-shaped base material, wherein space saving is achieved by making the width of the gasket as small as possible. In order to achieve the foregoing, the following are provided: the film, sheet, or plate-shaped base material; the gasket that is provided integrally with the base material and that is formed of a rubbery elastic material; and a fill layer formed by the rubbery elastic material that is filled into a through hole that is provided in an open state in the base material. A portion of the fill layer is connected to the gasket and another portion extends out from the gasket at substantially the same thickness as the base material.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a 371 U.S. National Stage Application of International Application No. PCT/JP2013/077202, filed on Oct. 7, 2013, and published in Japanese as WO 2014/069172 A1 on May 8, 2014. This application claims priority to Japanese Application No. 2012-241597, filed on Nov. 1, 2012. The entire disclosures of the above applications are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a base material integrated type seal in which a gasket is integrally formed in a film, a sheet or a plate-like base material, for example, a seal for a fuel battery which is provided for sealing a flow path formed in each of fuel battery cells of a fuel battery stack, and further relates to a metal mold which is used for manufacturing the same. 
         [0004]    2. Description of the Conventional Art 
         [0005]    The fuel battery is used in a wide intended purpose from a fuel batter for a compact power supply having about several tens W to an automotive power supply of 100 kW class, by mainly forming a fuel battery cell obtained by pinching a power generating body which includes an MEA (membrane electrode assembly) provided with a pair of electrode layers in both surfaces of an electrolyte membrane by separators, and forming a stack structure by laminating the fuel battery cells. A fluorine-based solid polymer membrane is mainly used for the electrolyte membrane of the MEA, and a proton conductivity is demanded. On the other hand, the separator is formed a flow path for supplying fuel gas (hydrogen gas) and oxidant gas (air including oxygen) to the electrolyte membrane, and has an important role which transmits electrons generated in an anode side on the basis of an electrochemical reaction. 
         [0006]    Further, in this kind of fuel battery, it is necessary to seal the fuel battery so as to prevent the fuel gas and the oxidization gas, water and surplus gas created by the reaction thereof, and cooling water for cooling the stack from leaking out to an external portion or being mixed with each other. 
         [0007]      FIG. 6  shows a conventional base material integrated type seal which is applied as a seal for a fuel battery, together with a part of the fuel battery. The base material integrated type seal  100  is constructed by integrally forming gaskets  102  and  102  which are made of a rubber-like elastic material (a rubber material or a synthetic resin material having a rubber-like elasticity) on both surfaces in a thickness direction of a film, a sheet or a plate-like base material  101  which is constructed by an MEA or a synthetic resin film arranged so as to surround an outer periphery of the MEA. Each of the gaskets  102  is constructed by a flat base  102   a  which is bonded to a surface of the base material  101 , and a seal lip  102   b  which is formed so as to protrude like a chevron from the base  102   a.  Further, the base material integrated type seal  100  is interposed between outer peripheral portions of the separators  200  and  200  in the fuel battery cell, and the seal lips  102   b  and  102   b  in the gaskets  102  and  102  are brought into close contact with bottom surfaces of seal grooves  201  and  201  which are formed in the separators  200  and  200  in a compressed state, whereby the base material integrated type seal  100  achieves a seal function against the fuel gas, the oxidization gas or the cooling water. 
         [0008]    The bases  102   a  and  102   a  of the gaskets  102  and  102  have protruding portions  102   c  and  102   c  which protrude in their width direction. The protruding portions  102   c  and  102   c  are connected to each other via a filling layer  103  infilling a through hole  101   a  which is provided in the base material  101 . In other words, the gaskets  102  and  102  are connected to each other via the filling layer  103 . The protruding portions  102   c  and  102   c  may be formed over a whole length of the base  102   a.    
         [0009]      FIGS. 7 and 8  show a metal mold  300  for manufacturing the base material integrated type seal  100  by integrally forming the gaskets  102  and  102  in the base material  101 . More specifically, the base material integrated type seal  100  is obtained by setting the base material  101  within the metal mold  300  which is constructed by an upper mold  301  and a lower mold  302  so as to mold clamp, and filling a liquid-like rubber for molding from an injection gate  304  provided in the upper mold  301  into cavities  303  and  303  which are defined by the base material  101  and inner surfaces of the upper mold  301  and the lower mold  302  so as to bridge and cure. 
         [0010]    The through hole  101   a  for shaping the molding liquid-like rubber injected from the injection gate  304  into the cavities  303  and  303  in both sides of the base material  101  is necessarily provided at a position which is deviated from the seal lips  102   b  and  102   b  while taking “sink” on the basis of a bridging and curing into consideration. As a result, the cavities  303  and  303  corresponding to the molding space have expansion portions  303   a  and  303   a  which form the protruding portion  102   c  of the base  102   a  in the gasket  102 , and the injection gate  304  and the through hole  101   a  of the base material  101  are provided at positions which correspond to the expansion portions  303   a  and  303   a  (refer to Japanese Unexamined Patent Publication No. 2011-96545). 
       SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
       [0011]    However, since the conventional base material integrated type seal  100  has the protruding portions  102   c  and  102   c  protruding in their width direction in the bases  102   a  and  102   a  of the gaskets  102  and  102 , it is unavoidable to make the widths of the seal grooves  201  and  201  formed in the separators  200  and  200  for accommodating the gaskets  102  and  102  wider at the degree of the protruding portions  102   c  and  102   c.  As a result, there has been a problem that a power generation area surrounded by the seal grooves  201  and  201  becomes relatively smaller. 
         [0012]    The present invention is made by taking the above points into consideration, and a technical problem of the present invention is to achieve a space saving by making a width of a gasket as small as possible in a base material integrated type seal in which the gasket is integrally formed in a film, a sheet or a plate-like base material. 
       Means for Solving the Problem 
       [0013]    As a means for effectively solving the technical problem mentioned above, a base material integrated type seal according to the invention of a first aspect has a film, a sheet or a plate-like base material, a gasket which is made of a rubber-like elastic material integrally provided in the base material, and a filling layer which is made of a rubber-like elastic material filled into a through hole provided in the base material, wherein the filling layer is structured such that a part of the filling layer is connected to the gasket and the other part protrudes out of the gasket while being approximately flush with the base material. The rubber-like elastic material is a rubber material or a synthetic resin material having a rubber-like elasticity. 
         [0014]    According to the structure of the first aspect, the gasket made of the rubber-like elastic material integrally provided in the base material is structured such as to be connected to the filling layer which is made of the rubber-like elastic material filled in the through hole provided in the base material. Further, the filling layer protrudes out of the gasket, however, is formed within the through hole provided in the base material so as to be approximately flush with the base material, that is, formed at a thickness which is approximately equal to the base material. As a result, a size in the width direction of the gasket is substantially small. Accordingly, the seal groove for accommodating the gasket in an installed state to the device is not necessarily set to be a width which can accommodate the filling layer. Therefore, it is possible to make the width of the seal groove small. 
         [0015]    A base material integrated type seal according to the invention of a second aspect is the structure described in the first aspect, wherein the gasket is provided in both sides in a thickness direction of the base material. 
         [0016]    According to the structure of the second aspect, the gaskets made of the rubber-like elastic material in both sides in the thickness direction of the base material are structured such as to be connected to each other via the filling layer which is made of the rubber-like elastic material filled in the through hole provided in the base material. 
         [0017]    A metal mold for manufacturing a base material integrated type seal according to the invention of a third aspect is a metal mold for obtaining the base material integrated type seal described in the first or second aspect by integrally forming the gasket made of the rubber-like elastic material in the film, the sheet or the plate-like base material, wherein the metal mold is constructed by a plurality of split molds, an injection gate is open between a plurality of split molds at a position which is spaced from the cavity, the injection gate injecting a liquid-like rubber for molding into a cavity which is defined between the base material and inner surfaces of the split molds in a state in which the base material is positioned and set between the split molds so as to be mold clamped, and the base material is positioned in such a manner that the through hole provided in the base material is communicated with both of the cavity and the injection gate. 
         [0018]    According to the structure of the third aspect, in the case that the film, the sheet or the plate-like base material is positioned and set between a plurality of split molds so as to be mold clamped, the through hole provided in the base material is communicated with both of the cavity which is defined between the base material and the inner surface of the split molds by the mold clamping, and the injection gate which is open between a plurality of split molds at the position which is spaced from the cavity. Therefore, in the case that the liquid-like rubber for molding is injected from the injection gate, the liquid-like rubber for molding is filled into the cavity via the through hole and is shaped. Further, the bridged and cured portion of the liquid-like rubber for molding within the cavity forms the gasket which is made of the rubber-like elastic material integrally formed with the base material, and the bridged and cured portion of the liquid-like rubber for molding within the through hole forms the filling layer structured such that a part is connected to the gasket and the other part protrudes out of the gasket while being approximately flush with the base material. 
       Effect of the Invention 
       [0019]    On the basis of the base material integrated type seal according to the present invention, it is possible to make the width of the gasket substantially small. As a result, it is possible to achieve a space saving. 
         [0020]    On the basis of the metal mold for manufacturing the base material integrated type seal according to the present invention, it is possible to obtain the base material integrated type seal which achieves the space saving by making the width of the gasket substantially smaller. 
     
    
     
       BRIEF EXPLANATION OF THE DRAWINGS 
         [0021]      FIG. 1  is a perspective view of a substantial part cross section and shows a seal for a fuel battery as an embodiment of a base material integrated type seal according to the present invention; 
           [0022]      FIG. 2  is a cross sectional view of a substantial part and shows the seal for the fuel battery as the embodiment of the base material integrated type seal according to the present invention by cutting in a portion A in  FIG. 1  together with a part of the fuel battery; 
           [0023]      FIG. 3  is a cross sectional view of a substantial part and shows the seal for the fuel battery as the embodiment of the base material integrated type seal according to the present invention by cutting in a portion B in  FIG. 1  together with a part of the fuel battery; 
           [0024]      FIG. 4  is a perspective view of a substantial part cross section and shows a metal mold for manufacturing the seal for the fuel battery as the embodiment of the base material integrated type seal according to the present invention together with the manufactured fuel battery; 
           [0025]      FIG. 5  is a cross sectional view of a substantial part and shows the metal mold for manufacturing the seal for the fuel battery as the embodiment of the base material integrated type seal according to the present invention together with the positioned and set base material; 
           [0026]      FIG. 6  is a partly cross sectional view showing a conventional seal for a fuel battery together with a part of the fuel battery; 
           [0027]      FIG. 7  is a perspective view of a substantial part cross section and shows a metal mold for manufacturing the conventional seal for the fuel battery together with the manufactured seal for the fuel battery; and 
           [0028]      FIG. 8  is a partly cross sectional view showing the metal mold for manufacturing the conventional seal for the fuel battery together with the positioned and set base material. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0029]    A description will be given below of preferred embodiments of a base material integrated type seal and a metal mold for manufacturing the base material integrated type seal according to the present invention with reference to the accompanying drawings. 
         [0030]    First of all,  FIGS. 1 to 3  show a preferable embodiment in which a base material integrated type seal according to the present invention is applied as a seal for a fuel battery. 
         [0031]    The base material integrated type seal  1  is structured, as shown in  FIG. 1 , such that gaskets  12  and  12  made of a rubber-like elastic material are integrally formed in both surfaces in a thickness direction of a base material  11  which is constructed by an MEA or a synthetic resin film (a synthetic resin plate) arranged in such a manner as to surround an outer periphery of the MEA. Each of the gaskets  12  is constructed by a flat base  12   a  which is bonded to a surface of the base material  11 , and a seal lip  12   b  which is formed so as to protrude like a chevron from the base  12   a.  Further, the base material integrated type seal  1  is interposed between outer peripheral portions of separators  2  and  2  in a fuel battery cell, and the seal lips  12   b  and  12   b  in the gaskets  12  and  12  are brought into close contact with bottom surfaces of seal grooves  21  and  21  formed in the separators  2  and  2  in a compressed state, as shown in  FIGS. 2 and 3 , whereby the base material integrated type seal  1  achieves a seal function against fuel gas, oxidizing gas or cooling water. 
         [0032]    A plurality of through holes  11  a are provided in the base material  11  at positions which are deviated in a width direction from the seal lip  12   b  of the gasket  12  at an appropriate distance along an extending direction of the gasket  12 , a filling layer  13  constructed by a rubber-like elastic material is filled within the through hole  11  a, and the filling layer  13  is structured such that a part is connected to the bases  12   a  and  12   a  in the gaskets  12  and  12  and the other part protrudes out of the gaskets  12  and  12  so as to be approximately flush with the base material  11 , that is, at an approximately equal thickness to the base material  11 . 
         [0033]    Therefore, the gaskets  12  and  12  in both sides of the base material  11  are connected to each other via the filling layer  13  which is protruded and formed so as to be approximately flush with the base material  11  at the appropriate distance from the bases  12   a  and  12   a,  that is, at the approximately equal thickness to the base material  11 . 
         [0034]      FIGS. 4 and 5  shows a preferable embodiment of a metal mold according to the present invention for manufacturing the base material integrated type seal  1  shown in  FIG. 1  by integrally forming the baskets  12  and  12  in the base material  11 . The metal mold  3  according to the embodiment is constructed by an upper mold  31  and a lower mold  32 , and groove-like concave portions  31   a  and  32   a  are formed in inner surfaces of the upper mold  31  and the lower mold  32 , the groove-like concave portions  31  a and  32   a  forming cavities  33  and  33  for forming the gaskets  12  and  12  shown in  FIG. 1  between both surfaces of the base material  11  positioned and set therebetween. The upper mold  31  and the lower mold  32  correspond to the split mold described in the third aspect. 
         [0035]    A plurality of injection gates  34  for injecting a liquid-like rubber for molding to the cavities  33  and  33  are provided in the upper mold  31 , and the injection gate  34  is open between the upper mold  31  and the lower mold  32  at a position which is spaced from the groove-like concave portions  31  a and  32   a  (the cavities  33  and  33 ). 
         [0036]    On the other hand, a plurality of through holes  11  a are previously provided in the base material  11  at appropriate distances along an extending direction of the cavities  33  and  33 . Further, the providing position of the through hole  11  a is set in such a manner that a part of the through hole is positioned between the cavities  33  and  33  and the other part protrudes in the width direction from between the cavities  33  and  33  in a state in which the base material  11  is positioned and set between the upper mold  31  and the lower mold  32 . 
         [0037]    Further, the providing position of the injection gate  34  provided in the upper mold  31  is set in such a manner as to be open toward each of the through holes  11  a of the base material  11  in the case that the base material  11  is positioned and set between the upper mold  31  and the lower mold  32 . 
         [0038]    Therefore, in order to manufacture the base material integrated type seal  1  shown in  FIG. 1  by using the metal mold  3  having the structure mentioned above, the base material  11  is first of all positioned and set between the upper mold  31  and the lower mold  32  so as to be mold clamped. At this time, the injection gate  34  provided in the upper mold  31  is open toward the through hole  11  a provided in the base material  11 , and a part of the through hole  11  a is positioned between the cavities  33  and  33  which are defined between the base material  11  and the groove-like concave portions  31  a and  32   a  of the upper mold  31  and the lower mold  32  by mold clamping. As a result, the through hole  11   a  is communicated with both of the cavities  33  and  33  and the injection gate  34 . 
         [0039]    Therefore, in the mold clamping state mentioned above, the molding liquid-like rubber injected from the injection gate  34  of the upper mold  31  is filled within the cavities  33  and  33  in both sides of the base material  11  via the through hole  11  a of the base material  11  and is shaped. Further, the portion that the liquid-like rubber for molding is bridged and cured within the cavities  33  and  33  is formed as the gaskets  12  and  12  which is made of the rubber-like elastic material, and is integrated with the base material  11 , and the portion that the liquid-like rubber for molding is bridged and cured within the through hole  11  a is connected in its part to the gaskets  12  and  12  and is approximately flush with the base material  11  in its other part so as to be formed as the filling layer  13  which protrudes out of the gaskets  12  and  12 , so that the base material integrated type seal  1  shown in  FIG. 1  is obtained. 
         [0040]    At this time, since the injection gate  34  is at the position which is deviated from the cavities  33  and  33  and is open toward the through hole  11  a, it is possible to suppress an adverse effect caused by “sink” applied to the main body portion of the gaskets  12  and  12  which are formed within the cavities  33  and  33 . 
         [0041]    The base material integrated type seal  1  in  FIG. 1  which is manufactured as mentioned above is formed within the through hole  11  a which is provided in the base material  11  so as to be approximately flush with the base material  11 , that is, at approximately the same thickness as the base material  11  although the filling layer  13  connecting the gaskets  12  and  12  in both sides of the base material  11  to each other protrudes out of the gaskets  12  and  12 . As a result, the size in the width direction of the gaskets  12  and  12  (the bases  12   a  and  12   a ) is substantially small. Therefore, as shown in  FIG. 2 , the seal grooves  21  and  21  of the separators  2  and  2  are not necessarily formed with the width which can accommodate a whole from the gaskets  12  and  12  to the filling layer  13 , so that it is possible to make the width of the seal grooves  21  and  21  small. 
         [0042]    Therefore, an occupied area of the seal grooves  21  and  21  in the fuel battery cell is reduced. As a result, the power generating area (not shown) formed in the inner peripheral side of the seal grooves  21  and  21  does not become relatively small, and it is possible to achieve a space saving. 
         [0043]    In the embodiment mentioned above, the description is given on the assumption that the base material  11  is the synthetic resin film (the synthetic resin plate) which is arranged so as to surround the MEA in the fuel battery cell or the outer periphery of the MEA, however, the present invention can be applied to the case that the base material  11  is the separator, the other films, the sheet or the plate-like member. 
         [0044]    Further, in the embodiment mentioned above, the description is given on the assumption that the basket  12  is provided on both surfaces in the thickness direction of the base material  11 , however, the present invention can be applied to the case that the gasket  12  is provided on one surface of the base material  11 .