Patent ID: 7093861

Claim:
an automobile exhaust-pipe joint structure, comprising: a first exhaust pipe having a first flange section at one end; a second exhaust pipe having a second flange section at one end; a ball joint mechanism disposed at the ends where the first flange section of the first exhaust pipe and the second flange section of the second exhaust pipe are formed to flexibly join the first exhaust pipe and the second exhaust pipe together; and joint mechanisms disposed in a plurality of positions at the first flange section and the second flange section, for joining the first flange section and the section flange section together; wherein one of the joint mechanisms includes: a bolt, one end of which is fixed to the second flange section through the first flange section; and a coil spring disposed between the other end of the bolt and the first flange section; wherein the cross section of the wire rod of the coil spring is a deformed cross section having a minor axis and a major axis such that it is small in diameter in the direction in which the coil spring is compressed, the dimension ratio of the major axis to the minor axis being within the range from 1.1 to 2.6.