Method of, and apparatus for, manufacturing metallic bellows

An apparatus for manufacturing a metallic bellows comprising:

• bulging means for bulging a straight raw pipe so as to form a corrugated bellows section on a periphery of the straight raw pipe, thereby obtaining a primary formed body;
• roll-machining means for subjecting at least one of crest portions and trough portions of the bellows section of the primary formed body to roll machining, the roll-machining means having a pair of forming rolls, one of the forming rolls having formed on a periphery thereof annular projections which come into radial contact with the crest portions or the trough portions of the bellows section, the other of the forming rolls having formed on a periphery thereof annular restricting grooves which restrict the periphery of the crest portions or the trough portions of the bellows section;
• urging means, disposed on the other of the forming rolls, for applying a radial urging force to the primary formed body in a state in which one of the forming rolls is inserted into the primary formed body;
• and
• rotating means for rotating said one of the forming rolls in a state in which the urging force is being applied.