PURPOSE: To obtain the curved hollow pipe having high dimensional accuracy and good productivity by setting a tubular piece to the plug curved with the specified radius of curvature and ironing in order from the one end by a rocking die.
CONSTITUTION: The piece subjected to primary forming is set to the plug 1 curved to the specified curvature and a die 2 is rocked with the center of the radius of curvature of the plug 1 as the shaft to subject the piece to ironing. The bending curvature of a curved pipe becomes correct and due to the thickness being regulated by the gap of the plug 1 and the inner peripheral face of a die hole 7 a thickness deviation and flattening phenomenon are prevented. Also, the curved pipe having various sections can be manufactured by varying the sectional shape of the plug 1 and die 7 shape adequately.
| JP2005349473 | RING WITH FLANGE, AND APPARATUS AND METHOD SUITABLE FOR FORMING RING WITH FLANGE |
| JPH0327819 | BENDER |
WATANABE KAKUJI
HORI SEIICHIRO
| JP42013388A | ||||
| JP40008656A | ||||
| JPS62275526A | 1987-11-30 | |||
| JPS60127021A | 1985-07-06 |