PURPOSE: To provide a method and device for manufacturing a bent tube, in which the limit of a bend radius is improved, the ratio of uneven thickness of a bent tube manufactured is minimized, and also the outside diameter of the bent tube manufactured may be set arbitrarily.
CONSTITUTION: The method and device are constituted of a contracting process, in which a straight tube stock 11 is force-fitted inside a hollow member 14 with its inner diameter smaller than the outer diameter of the tube stock so as to contract the diameter of the tube stock, and an expanding and bending- force imparting process in which a bent tube is manufactured by expanding the contracted part 11a and also by imparting a bending force to a part 11b immediately after the expansion in the tube stock in a state where a part 11a immediately before the expansion in the tube stock is guided from the radial direction.
TAKEDA SHIN
NAKAMURA MASAO
NAKAMURA MASAO