| 摘要 |
PURPOSE:To manufacture an inexpensive exhaust silence with high production efficiency, by dividing a pipe-contracting process of a material consisting of a metallic cylindrical body, into 2 stages, performing its 2 processes, and obtaining a worked product of one body. CONSTITUTION:An exhaust silence material 5 of prescribed length is cut off from a metallic cylindrical body having a prescribed outside diameter. As for length of the material 5, a material of both end parts 5a to be formed by working is estimated. Subsequently, both the end parts 5a are formed by primary pipe-contraction to a prescribed outside diameter by means of spinning working which includes annealing of the exhaust silencer material 5. After that, both the end parts 5a are subjected to swaging-working, furthermore secondary pipe- contraction to the prescribed outside diameter is performed, and also the pipe is elongated to prescribed length, by which an exhaust silencer 6 is obtained. |
