Die cushion apparatus of press machine

A die cushion apparatus of a press machine, comprising:

• a plurality of fluid hydraulic cylinders that support a cushion pad;
• a plurality of pressure detectors that detect a pressure of a pressure chamber on a cushion pressure production side of each fluid hydraulic cylinder, respectively;
• a plurality of fluid hydraulic pump/motors having a discharge opening that is connected through a first pipe to a pressure chamber on the cushion pressure production side of each fluid hydraulic cylinder;
• a plurality of electric motors that are respectively connected to a rotating shaft of each fluid hydraulic pump/motor;
• a die cushion pressure command device that outputs a die cushion pressure command that is previously set;
• a control device that controls a torque of each electric motor so that a die cushion pressure is a pressure that corresponds to the die cushion pressure command based on the die cushion pressure command and pressures that are detected by the plurality of pressure detectors;
• and
• a regeneration device that regenerates energy required for a die cushioning action that the cushion pad receives when die cushioning of a press machine is effected as electrical energy through the plurality of fluid hydraulic cylinders, fluid hydraulic pump/motors and electric motors.