Method for producing a bellows with oval cross section and apparatus for carrying out the method

摘要

After a metallic cylindrical tube is bulged to form a bellows with a circular cross section, this bellows is ovalized to form a bellows with an oval cross section. For this reason, an inexpensive round tube (cylindrical tube) can be used as the material for a bellows with an oval cross section and it is unnecessary to use an expensive oval tube. Accordingly, a bellows with an oval cross section can be produced at low cost.