To enable high-accuracy form rolling in a form-rolling device without necessitating adjustment of distance between a center of a pair of dies and a center of an object workpiece.
Form rolling is performed in a sate of sandwiching an object workpiece 2 in between a pair of dies 3, 3. Hydraulic oil chambers 7A, 7A for hydraulic cylinders 7, 7 adapted to press the pair of dies 3, 3 to the object workpiece 2 are communicated with each other through a communication pipeline 8. Hydraulic oil is fed to the communication pipeline 8 by means of a pump 9, in which a pressure in the communication pipeline 8 is kept constant during form rolling by a constant pressure valve 10. As a result, pressures in the hydraulic cylinders 7, 7 are kept constant and equal each other, thereby enabling a form-rolling force generated by the pair of dies 3, 3 to be retained always constant and uniform, and an accuracy of the form rolling to be improved.
Miyazaki Yoshio
Kaoru Onozuka
Tsutomu Kato
Akio Tagami
High Masahiro
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