Aida Engineering, Ltd.

Minoru Somukawa

Yasuyuki Kohno

Tadahiro Kondo

Kazufumi Tsuchida

A die cushion force control method and a die cushion apparatus generates a die cushion force on a cushion pad based on a die cushion force command value set in advance. A die cushion force command value equal to or larger than a target die cushion force command value is outputted initially in order to suppress an initial die cushion force overshoot generated when the target die cushion force command value configured to be stepwise is used as the die cushion force command value, then a die cushion force command value decreased continuously (gradually) so as to be smaller than the target die cushion force command value is outputted, and subsequently a die cushion force command value increasing gradually so as to be equal to the target die cushion force command value is outputted.

Die cushion force control method and die cushion apparatus

A die cushion apparatus of a press machine in which a discharge opening of a fluid hydraulic pump/motor is directly connected to a pressure chamber on a cushion pressure production side of a fluid hydraulic cylinder and the torque of a rotating shaft of the fluid hydraulic pump/motor is controlled by an electric motor to control a pressure (die cushion pressure) of the pressure chamber on the cushion pressure production side. It is therefore possible to control the die cushion pressure with excellent responsiveness with respect to a die cushion pressure command and prevent occurrence of a surge pressure. The die cushion apparatus also has excellent energy efficiency since energy required for a die cushioning action that a cushion pad receives when effecting die cushioning of a press machine is regenerated as electrical energy through the fluid hydraulic cylinder, fluid hydraulic pump/motor, and electric motor.

Die cushion apparatus of press machine

A slide of a press machine is driven by composite thrust of thrust of an electric (servo) motor SM (via a screw/nut mechanism from the electric motor) and thrust of hydraulic cylinders SYL, SYLto which pressure oil is supplied from a constant, high pressure source. A slide control device controls the electric motor SM and the hydraulic cylinders SYL, SYL, based on a slide position signal and a motor angular velocity signal, and at the same time, makes the hydraulic cylinder SYLwork as a pump during a period when slide load is small, charging pressure oil to the constant, high pressure source by using the thrust transferred from the electric motor to the hydraulic cylinder SYLthrough the screw/nut mechanism and the slide.

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Sagamihara, Japan

Minoru Somukawa