Patent ID: 8850865

Claim:
A die cushion device comprising: a cushion pad; a support section supporting the cushion pad; a servomotor configured to raise and lower the support section for raising and lowering the cushion pad, the servomotor being part of a drive section that includes a ball screw and at least one pulley; and a shock absorber device configured to relieve a shock between the cushion pad and the support section, the shock absorber device including a liquid pressure chamber filled with a liquid, the liquid pressure chamber being disposed between the cushion pad and the support section, a liquid flow path allowing the liquid to pass there-through, the liquid flow path being connected to the liquid pressure chamber, an orifice disposed in the liquid flow path, and configured to generate a reaction force in accordance with a relative speed of the cushion pad with respect to the support section by restricting the liquid flow path, an accumulator disposed in the liquid flow path, and configured to generate a reaction force in accordance with a relative displacement of the cushion pad with respect to the support section; and a check valve provided in the liquid flow path between the orifice and the accumulator, the check valve being connected in series with respect to the orifice and arranged to prevent a reverse flow of the liquid from the accumulator toward the liquid pressure chamber through the orifice, the orifice and the accumulator being arranged in the liquid flow path such that the liquid flows from the liquid pressure chamber to the accumulator and through the orifice and the check valve when the shock occurring between the cushion pad and the support section causes the liquid pressure chamber to be compressed.