Manufacturing method and manufacturing apparatus for metallic bellows

摘要

A manufacturing method for manufacturing a bellows having pleat walls with S-shaped profiles comprises a primary forming process for forming a formed bellows, a pressing process for compressing the formed bellows in the axial direction, and a stretching process for pulling the compressed bellows in the axial direction, thereby obtaining desired pitches and free length. After the stretching process is carried out, the bellows is subjected to an annealing and ageing heat-treatment process. An apparatus for manufacturing the bellows comprises a pair of molds that have their respective forming surfaces in shapes corresponding individually to the pleat walls. The die is slightly retreated away from the pleat walls just before the dies open in the diametrical direction after the pleat walls are formed.