PRESS BRAKE AND METHOD OF CONTROLLING BIDIRECTIONAL FLUID PUMP OF HYDRAULIC CYLINDER OF PRESS BRAKE

摘要

A controller (18) controls an AC servomotor (39) to reverse the rotation of a bidirectional piston pump (31) so as to reverse the vertical movements of a ram (5U). The controller (18) includes a command generator (65) that produces a command to maintain the ram (5U) at a constant speed for a predetermined warm-up time after a reverse of the ram movement and change the ram speed to a predetermined speed. A command position counter (67) reads the ram position from the ram speed pattern, and an adder (73) sums the read value and the value associated with the actual position of the ram (5U) and detected from a position detector (11) to control the rotation of the AC servo motor (39).