To enable hydroforming which enables branch bulge height to be enlarged without using counters and has a large root part curvature of a branch root part and also has a complex shape in the branch pipe part.
A hydroforming apparatus includes: movable dies which are divided into two in the direction of the pipe axis and also, are stacked in the direction perpendicular to the pipe axis, and, while being driven by a driving means, is capable of retreating and advancing in the direction of the pipe axis during hydroforming processes; a fixed die for holding the movable dies from outside; an internal pressure giving means for applying the internal pressure by supplying liquid to the inside of a metallic pipe; and an axially pressing punch movable in the direction of the pipe axis. The metallic pipe is installed in the movable dies in such a condition that all movable dies are advanced, and the movable dies are clamped with the fixed die. While applying the pushing force in the direction of the pipe axis to the metallic pipe by means of the axially pressing punch, the pipe is expanded to have a branch pipe part by retreating the layers one by one in the order from the first layer to the outmost layer of the movable dies, providing that the first layer of the movable dies is on the near side to the metallic pipe and the outmost layer is on the farthest side from the metallic pipe.
JPH10296347A | 1998-11-10 | |||
JPS632523A | 1988-01-07 | |||
JP2005288532A | 2005-10-20 | |||
JPS5633131A | 1981-04-03 |
Takashi Ishida
Tetsuji Koga
Hiroshi Kamematsu
Hideo Tokunaga
Nakamura Asayuki
Nagasaka Tomoyasu