| 摘要 |
A method of manufacturing a ball valve having a valve housing (10) and a bal l (20), comprising the steps of weld-connecting a pair of housing halves (12) and (14) in mirror symmetrical shape through a single weld line so as to surround the ball having a through hole and a pair of recessed parts provide d therein beforehand with the through hole (22) directed so as to be aligned with the weld line, forming holes (42) and (50) having the centers on the operating center line of the ball valve for mounting a pair of pivot shaft portions by machining in the valve housing at the positions aligned with bot h opening ends of the through hole, rotating the ball by an angle of 90~to ali gn the through hole of the ball with the openings (12A, 14A) of the valve housi ng and also align the recessed parts (26, 28) of the ball with the holes of the housing, and installing the pair of pivot shaft portions (60, 68) into two holes, inserting pivot shafts into two recessed parts, and weld-connecting t he periphery of the pair of pivot shaft portions to the edge portions of the holes. |
