Drive apparatus, press machine slide drive apparatus and method thereof

A press machine slide drive apparatus, comprising:

• an electric motor;
• a fixed capacity type or variable capacity type hydraulic pump/motor connected to a constant high pressure source that generates a quasi-constant high pressure hydraulic liquid and a low pressure source;
• a slide drive mechanism which drives a slide of a press machine;
• and
• a power transmitting device which mechanically connects a drive axis of the slide drive mechanism and the electric motor in such a way that torque is transmitted between the drive axis of the slide drive mechanism and the electric motor and mechanically connects the drive axis and the hydraulic pump/motor in such a way that torque is transmitted between the drive axis and the hydraulic pump/motor.

A press machine slide drive apparatus, comprising:

• an electric motor;
• a fixed capacity type or variable capacity type hydraulic pump/motor connected to a constant high pressure source that generates a quasi-constant high pressure hydraulic liquid and a low pressure source;
• a plurality of slide drive mechanisms which drives one slide of the press machine;
• and
• a power transmission device which mechanically connects each drive axis and the electric motor in the plurality of slide drive mechanisms in such a way that torque is transmitted between each drive axis and the electric motor and mechanically connects the each drive axis and the hydraulic pump/motor in such a way that torque is transmitted between the each drive axis and the hydraulic pump/motor.

A press machine slide drive method, comprising the steps of:

• driving an electric motor and-mechanically connected to a drive axis, thereby generating torque;
• generating torque from a fixed capacity type or variable capacity type hydraulic pump/motor by connecting the hydraulic pump/motor to a constant high pressure source which generates a quasi-constant high pressure hydraulic liquid and low pressure source;
• and
• combining and acting the output torque of the electric motor and the output torque of the hydraulic pump/motor on the drive axis when the output torque of at least the single electric motor unit is not sufficient as the torque output to the drive axis of the press machine slide drive mechanism.