| 摘要 |
PURPOSE:To increase the strength and enhance productivity by forming a steel plate into a cylinder, providing it with a guide groove at its outside surface, making a full cylinder through conjunction of the butted parts of said steel plate, and then fitting caps on both ends of this cylinder. CONSTITUTION:A steel plate is rounded by a press until the two edges butt, and a plurality of guide grooves 2 are formed at the outside surface of this steel plate in its direction of rounding. The butted parts of this steel plate are jointed by plasma arc welding to form a cylinder. Then caps 3, 4 are fitted on both ends of this cylinder and fixed by plasma arc welding to accomplish a change drum A. Thereafter the abovementioned guide grooves 2 are fine shaped by trace processing, and the welds W1-W3 are machined and finished and further the whole surfaces are flattened as well as shafting parts 3a, 4a of the caps polished. |
