US Patent 7475584 Servo-drive system and continuous finishing system of press

A servo drive system of a press machine has a pair of servo motors which can generate necessary ram pressure by compositing and using a torque based on the same speed-torque characteristics. The servo motors are symmetric with each other in a mirror image manner. The servo motors are opposed to each other at opposite ends of an operation shaft which vertically moves a ram. The servo motors are integrally operated, thereby directly driving the operation shaft.