| 摘要 |
PROBLEM TO BE SOLVED: To simplify the welding work of a pipe formed by plastically working one metallic sheet. SOLUTION: A front pipe 5 consists of an outer pipe 7 and an inner pipe 10. The outer pipe 7 is arranged so as to surround the outer periphery of the inner pipe 20 with a prescribed clearance. The inner pipe 10 is a flow passage- divided pipe provided with two flow passages 11, 12 for exhaust gas, is formed into almost bisected-circular shape at the cross section by plastically working are metallic sheet and is formed by welding (e.g. laser beam welding) the contact parts between flanges 13, 14 provided at both ends of the metallic sheet and the other part of the metallic sheet from the outsides. The cross section of the inner pipe 10 has a circular part 15 and a partition part 16. |
