| 摘要 |
PURPOSE: Structure of a hydraulic mandrel for tube hydro-forming is provided to bend a complicated section even without changing the design of a mandrel corresponding to the section of a tube by applying the hydro-forming technique. CONSTITUTION: A hydraulic mandrel(20) comprises an outer mandrel(21) installed in a tube(100) and a pair of inner mandrels(22,23) performing as a valve in the outer mandrel. The inner mandrels open and close penetrated flow paths(26a,26b) selectively. The first inner mandrel is installed in the outer mandrel. The second inner mandrel is connected to the lower face of the first inner mandrel. The first inner mandrel slides in the outer mandrel by the elastic supporting of an elastic spring(28). If the first inner mandrel contacts with the second inner mandrel, the leakage of a fluid from the tube is prevented. |
