Spherical annular seal member and method of manufacturing the same

A spherical annular seal member which has a cylindrical inner surface defining a through hole in a central portion thereof, a partially convex spherical outer surface, and an annular end face on a large-diameter side of the partially convex spherical outer surface, and which is used in an exhaust pipe spherical joint of an automobile, comprising:

• a reinforcing member made from a compressed metal wire net and provided in an inner portion of said spherical annular seal member which extends from the cylindrical inner surface to the partially convex spherical outer surface;
• a heat-resistant material containing compressed and expanded graphite, phosphorus pentoxide, and a phosphate, and provided in the inner portion of said spherical annular seal member, said heat-resistant material being composed of 0.05 to 5.0 wt. % of phosphorus pentoxide, 1.0 to 16.0 wt. % of the phosphate, and 79.0 to 98.95 wt. % of expanded graphite, and filling meshes of said metal wire net of said reinforcing member and compressed in such a manner as to be formed integrally with said reinforcing member in mixed form, said phosphorus pentoxide and said phosphate being mixed into said compressed and expanded graphite to suppress consumption of said compressed and expanded graphite due to oxidation of the same at temperatures of 600° C. to 700° C., the partially convex spherical surface being formed into a smooth surface where an outer surface layer of a lubricating composition containing at least boron nitride and at least one of alumina and silica and said reinforcing member made from the metal wire net and formed integrally with said lubricating composition in mixed form are exposed.

A spherical annular seal member which has a cylindrical inner surface defining a through hole in a central portion thereof, a partially convex spherical outer surface, and an annular end face on a large-diameter side of the partially convex spherical outer surface, and which is used in an exhaust pipe spherical joint of an automobile, comprising:

• a reinforcing member made from a compressed metal wire net and provided in an inner portion of said spherical annular seal member which extends from the cylindrical inner surface to the partially convex spherical outer surface;
• a heat-resistant material containing compressed and expanded graphite, phosphorus pentoxide, and a phosphate, and provided in the inner portion of said spherical annular seal member, said heat-resistant material filling meshes of said metal wire net of said reinforcing member and compressed in such a manner as to be formed integrally with said reinforcing member in mixed form, said phosphorus pentoxide and said phosphate being mixed into said compressed and expanded graphite to suppress consumption of said compressed and expanded graphite due to oxidation of the same at temperatures of 600° C. to 700° C., the partially convex spherical surface being formed into a smooth surface where an outer surface layer of a lubricating composition containing at least boron nitride and at least one of alumina and silica and said reinforcing member made from the metal wire net and formed integrally with said lubricating composition in mixed form are exposed, said lubricating composition containing 70 to 90 wt. % of boron nitride and 10 to 30 wt. % of at least one of alumina and silica.

A spherical annular seal member which has a cylindrical inner surface defining a through hole in a central portion thereof, a partially convex spherical outer surface, and an annular end face on a large-diameter side of the partially convex spherical outer surface, and which is used in an exhaust pipe spherical joint of an automobile, comprising:

• a reinforcing member made from a compressed metal wire net and provided in an inner portion of said spherical annular seal member which extends from the cylindrical inner surface to the partially convex spherical outer surface;
• a heat-resistant material containing compressed and expanded graphite, phosphorus pentoxide, and a phosphate, and provided in the inner portion of said spherical annular seal member, said heat-resistant material filling meshes of said metal wire net of said reinforcing member and compressed in such a manner as to be formed integrally with said reinforcing member in mixed form, said phosphorus pentoxide and said phosphate being mixed into said compressed and expanded graphite to suppress consumption of said compressed and expanded graphite due to oxidation of the same at temperatures of 600° C. to 700° C., the partially convex spherical surface being formed into a smooth surface where an outer surface layer of a lubricating composition containing at least boron nitride, at least one of alumina and silica, and polytetrafluoroethylene resin and said reinforcing member made from the metal wire net and formed integrally with said lubricating composition in mixed form are exposed, said lubricating composition containing a mixture consisting of 70 to 90 wt. % of boron nitride and 10 to 30 wt. % of at least one of alumina and silica, and further containing not more than 200 parts by weight of polytetrafluoroethylene resin with respect to 100 parts by weight of said mixture.

A spherical annular seal member which has a cylindrical inner surface defining a through hole in a central portion thereof, a partially convex spherical outer surface, and an annular end face on a large-diameter side of the partially convex spherical outer surface, and which is used in an exhaust pipe spherical joint of an automobile, comprising:

• a reinforcing member made from a compressed metal wire net and provided in an inner portion of said spherical annular seal member which extends from the cylindrical inner surface to the partially convex spherical outer surface;
• a heat-resistant material containing compressed and expanded graphite, phosphorus pentoxide, and a phosphate, and provided in the inner portion of said spherical annular seal member, said heat-resistant material filling meshes of said metal wire net of said reinforcing member and compressed in such a manner as to be formed integrally with said reinforcing member in mixed form, said phosphorus pentoxide and said phosphate being mixed into said compressed and expanded graphite to suppress consumption of said compressed and expanded graphite due to oxidation of the same at temperatures of 600° C. to 700° C., the partially convex spherical surface being formed into a smooth surface where an outer surface layer of a lubricating composition containing at least boron nitride, at least one of alumina and silica, and polytetrafluoroethylene resin and said reinforcing member made from the metal wire net and formed integrally with said lubricating composition in mixed form are exposed, said lubricating composition containing a mixture consisting of 70 to 90 wt. % of boron nitride and 10 to 30 wt. % of at least one of alumina and silica, and further comprising 50 to 150 parts by weight of polytetrafluoroethylene resin with respect to 100 parts by weight of said mixture.