Patent ID: 7475584

Claim:
A servo drive system of a press machine, comprising: a ram; an operation shaft which vertically moves the ram; a pair of servo motors which are formed symmetric to each other at opposite ends of the operation shaft, which operate as power sources of the ram, and which composite torques based in common on at least one speed-torque characteristic to generate ram pressure, a servo amplifier of one of the pair of servo motors, comprising a power unit; and a servo amplifier of the other of the pair of servo motors, comprising a power unit, wherein the pair of servo motors are operated integrally so that the pair of servo motors directly drive the operation shaft to vertically move the ram, and wherein the power unit of the servo amplifier of the one of the pair of servo motors and the power unit of the servo amplifier of the other of the pair of servo motor are driven by a common gate signal to integrally operate both of the pair of servo motors.