Patent ID: 7143617

Claim:
A press forming machine, comprising: a lower support stand; a plurality of columns supported by said lower support stand; an upper support plate held by said plurality of columns; a slide plate, said slide plate reciprocating between said lower support stand and said upper support plate and has a molding space defined between said slide plate and said lower support stand; a plurality of servo motors, said servo motors having drive shafts engaged to an upper surface of said slide plate to make a displacement on said slide plate; control means for controlling driving of each of said servo motors; engaging parts, said engaging parts are engaged to an upper surface of said slide plate and provided on said slide plate so as to correspond to said servo motors, said servo motors each having a drive shaft for pressing the engaging part to make a displacement on said slide plate; displacement measuring means for measuring a displacement according to a positional displacement of said slide plate, said displacement measuring means being disposed near each of said engaging parts; said control means comprising: means which measure a positional displacement of each of said motor servos by using a displacement measuring means in each of a plurality of operating steps during the molding operation in which a load from a workpiece acts on the slide plate, measures a positional displacement for each of said servo motors, the positional displacement corresponding to a change in load on each of said servo motors, detects a desired displacement position of the entire slide plate, extracts control data corresponding to said servo motors to maintain the entire slide plate at the desired displacement position, stores the control data in memory; and supplies the control data to said servo motors, and separately driving said servo motors.