Patent ID: 8046916

Claim:
A method of manufacturing a metallic bellows comprising: a first step of bulging a straight raw pipe into a primary formed body having formed on a periphery thereof a corrugated bellows section thereby creating at least a curved crest portion and a curved trough portion in the first step; and a second step of subjecting at least one of curved crest portions and curved trough portions of the bellows section of the primary formed body to roll machining by means of a pair of forming rolls, wherein the second step comprises: inserting a first forming roll into the primary formed body; applying an urging force to a second forming roll toward the first forming roll in a state in which annular projections formed on a periphery of one of the first forming roll and the second forming roll are radially in contact with the at least one of crest portions and trough portions of the bellows section; and rotating the first forming roll in a state in which the urging force by the second forming roll is being applied thereto, until the periphery of the at least one of the crest portions and the trough portions is restricted by annular restricting grooves formed on a periphery of the other of the first forming roll and the second forming roll.