(19)
(11) EP 0 092 253 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
20.03.1985 Bulletin 1985/12

(43) Date of publication A2:
26.10.1983 Bulletin 1983/43

(21) Application number: 83103876

(22) Date of filing: 20.04.1983
(84) Designated Contracting States:
AT BE CH DE FR GB IT LI LU NL SE

(30) Priority: 20.04.1982 JP 6611882
22.03.1983 JP 4752683

(71) Applicants:
  • Nakamura, Kazuhiko
     ()
  • Nakagawa, Takeo
     ()
  • Amino Iron Works Co., Ltd.
     ()

(72) Inventors:
  • Nakamura, Kazuhiko
     ()
  • Nakagawa, Takeo
     ()

   


(54) Metal sheet forming process with hydraulic counterpressure


(57) A punch is pressed on a blankpiece into a die. The die is filled with liquid therein, whereby hydraulic counterpressure is generated by said pressing. The pressed blankpiece is forcibly followed in shape around the punch by hydraulic counterpressure, while part of the hydraulic counterpressure is automatically supplied to an outer circumference of the blankpiece via bypath passage. In case, the blankpiece is a plate, said supplied hydraulic pressure serves as compression force from the outer circumference of the flange to the radius direction. In case, the blankpiece is a product formed by a first drawing, said pressure serves as pressing force toward axial direction of a side wall of the product. When the supplied hydraulic pressure flows out from a space between the punch and a blank holder, the liquid serves as lubrication on an upper and lower surfaces of the blankpiece.






Search report