| 摘要 |
PURPOSE:To improve the precision and reliability of welding by welding opening edges of exhaust pipes closely stuck to each other with a high-energy beam when downstream portions of exhaust pipes with a square cross section are to be closely welded. CONSTITUTION:The exhaust system of an engine is constituted of many exhaust pipes 16 (16a-16d) extended below a crank case from the front of cylinders, an exhaust control valve device 18 connected to rear ends of exhaust pipes 16 to collect the exhaust, and a collecting pipe 22 guiding the exhaust into a muffler 20. Branch pipes 24 (24a-24d) are connected to rear ends of exhaust pipes 16 respectively. Downstream portions of branch pipes 24 opened toward the exhaust control valve device 18 are formed into a square cross section. Opening edges of branch pipes 24 closely stuck to each other are welded with a high-energy beam from the exhaust control valve device 18 side. The precision and reliability of welding is improved. |
