FLEXIBLE EXHAUST GAS PIPE

PROBLEM TO BE SOLVED: To enhance surface rigidity of inner and outer layer thin plates in a center straight pipe, and prevent the deformation thereof caused by expansion of air, in a flexible exhaust gas pipe in which the inner and outer layer thin plates are folded, a straight pipe part is provided adjacently to a center part, and a wavy flexible part is provided adjacently to both sides of the straight pipe part, by forming a rib in the center straight pipe. SOLUTION: A first inner pipe 1 connected to the upstream side pipe of an exhaust gas system and a second inner pipe 2 connected to the downstream side pipe of the exhaust system, are arranged having a predetermined interval D from their mutual opposed ends, and connected to each other by being surrounded by a flexible exhaust gas pipe 3. The flexible exhaust gas pipe 3 is formed in a two-layer structure in which a metallic inner layer thin plate 3a and a metallic outer layer thin plate 3b are folded, the axial center part of the flexible exhaust gas pipe 3 is formed into a straight pipe part 3c, and both sides thereof are formed into wavy bellows parts 3d. In this case, ribs 3f formed by being projected from the general part of the center straight pipe part 3c, are formed in the center straight pipe part 3c, thereby the surface rigidity of the inner and outer layer thin plates 3a, 3b is enhanced, and resistance against the deformation thereof is enhanced.