Connecting structure for exhaust pipes

A connecting structure for exhaust pipes, comprising:

• a plurality of upstream exhaust pipes including downstream-end portions having peripheries;
• a first connecting flange connected to the peripheries of the downstream-end portions of said upstream exhaust pipes;
• a plurality of downstream exhaust pipes arranged so as respectively to correspond to said upstream exhaust pipes, said plurality of downstream exhaust pipes including upstream-end portion having peripheries;
• a second connecting flange connected to the peripheries of the upstream-end portions of said downstream exhaust pipes;
• and
• a plurality of spherical joints located between said first connecting flange and said second connecting flange for airtightly connecting said downstream end portions of said upstream exhaust pipes with said upstream end portions of said corresponding downstream exhaust pipes, respectively, each of said spherical joints comprising:
• an annular seal unit with a central opening for passage of exhaust gas, a spherical portion on one side of said annular seal unit, and a flat surface on the other side of said annular seal unit, said annular seal unit being held between said fist and second connecting flanges;
• a spherical bearing surface formed on one of said first and second connecting flanges in such a manner as to be brought into slidable spherical contact with the spherical portion formed on one side of said annular seal units, wherein said spherical bearing surface surrounds said central opening;
• and
• a flat bearing surface formed on the other one of said first and second connecting flanges, wherein said flat bearing surface is disposed so as to confront said annular seal unit such that said flat bearing surface contacts and is slidable with respect to the flat surface of said annular seal unit in a direction oblique to longitudinal axes of the exhaust pipes connected to said other one of said first and second connecting flanges.