Die cushion device

A die cushion device comprising:

• a first hydraulic cylinder configured to support a cushion pad and generate a die cushion force on the cushion pad in a case where a slide of a press machine is moved downward;
• a first hydraulic circuit configured to drive the first hydraulic cylinder;
• a first pressure commander configured to output a first pressure command indicating a die cushion pressure corresponding to the die cushion force;
• a first pressure detector configured to detect a pressure applied to a lower chamber of the first hydraulic cylinder;
• a first controller configured to control the first hydraulic circuit based on the first pressure command and the pressure detected by the first pressure detector, in such a manner that the pressure applied to the lower chamber of the first hydraulic cylinder matches a pressure corresponding to the first pressure command;
• a second hydraulic cylinder configured to support the cushion pad and move the cushion pad in an up-and-down direction;
• a second hydraulic circuit configured to drive the second hydraulic cylinder;
• a die cushion position commander configured to output a die cushion position command indicating a position of the cushion pad;
• a die cushion position detector configured to detect a position of the cushion pad;
• and
• a second controller configured to control the second hydraulic circuit based on the die cushion position command and the position of the cushion pad detected by the die cushion position detector, in such a manner that the position of the cushion pad matches a position corresponding to the die cushion position command,
• wherein:
• the first pressure commander outputs a second pressure command for pre-pressurizing the lower chamber of the first hydraulic cylinder to a preset pressure before press forming;
• the die cushion position commander outputs a first die cushion position command for causing the cushion pad to stand by at a die cushion standby position before press forming;
• the first controller controls the first hydraulic circuit based on the second pressure command and the pressure detected by the first pressure detector, to pre-pressurize the lower chamber of the first hydraulic cylinder to a pressure corresponding to the second pressure command;
• and
• the second controller controls the second hydraulic circuit based on the first die cushion position command, to cause the cushion pad to stand by at the die cushion standby position.