US 7,461,530 B2
Die cushion mechanism, and apparatus and method for controlling the same
Yasusuke Iwashita, Fujiyoshida (Japan); Tadashi Okita, Fujiyoshida (Japan); Hiroyuki Kawamura, Yamanashi (Japan); and Satoshi Ikai, Yamanashi (Japan)
Assigned to Fanuc Ltd, Minamitsuru-gun, Yamanashi (Japan)
Filed on Nov. 03, 2005, as Appl. No. 11/265,078.
Claims priority of application No. 2004-321311 (JP), filed on Nov. 04, 2004.
Prior Publication US 2006/0090656 A1, May 04, 2006
Int. Cl. B21C 51/00 (2006.01)
U.S. Cl. 72—20.1  [72/20.2; 72/21.4; 72/443; 72/454] 19 Claims
OG exemplary drawing
 
1. A control apparatus for controlling a die cushion mechanism including a servo-motor as a drive source and producing a force adapted to be applied to a slide in a press machine, comprising:
a force commanding section for commanding a force to be produced by said die cushion mechanism;
a force detecting section for detecting said force produced by said die cushion mechanism;
a motor-speed detecting section for detecting an operating speed of said servo-motor;
a slide-speed detecting section for detecting a moving speed of said slide; and
a force controlling section for executing a force control on said servo-motor, based on a force command value commanded by said force commanding section, a force detected value detected by said force detecting section, a motor-speed detected value detected by said motor-speed detecting section and a slide-speed detected value detected by said slide-speed detecting section.