| 摘要 |
<p>PROBLEM TO BE SOLVED: To dispense with machining when forming stepped part on a flange. SOLUTION: An outer casing 3 uses, in contrast with prior arts, a flange 4 which is consisted of an annular flange part 41 an a plurality of stepped parts 42. The respective stepped parts 42 are members 421 which are formed of rolled material as a standard item in a fan shape and arranged in an annular pattern, and fixedly secured to the flange part 41 by welding process. And, at the stepped parts formed at the locations where through-holes 411 are formed, the members 411 are arranged avoiding the locations where the through-holes 411 are formed. And, for fabricating the outer casing 3, a process which welds en bloc a main part 78, a rib 76 and the flange part 41 is first performed, and after that, the stepped parts 42 are fixedly secured to the flange part 41 by welding.</p> |
