Method for controlling a press with a variable gear ratio

Abstract

A method for controlling a press having an electric drive motor and a press transmission with a variable gear ratio (Ü) is disclosed. A tappet is movably mounted in a stroke direction (R) and is connected to the electric drive motor via the press transmission. The gear ratio (Ü) continuously increases as the tappet moves from an upper reversal point (OT) to a lower reversal point (UT). To prevent the press from exceeding a specified maximum pressing force (Fmax), a position-dependent maximum torque (Mmax) is specified for the motor. The control device compares each applied drive torque (M) with the maximum torque (Mmax). If the drive torque (M) exceeds the maximum torque (Mmax), the danger of the force applied by the tappet exceeding the maximum pressing force (Fmax) during an ongoing forming movement is detected. The control device then reduces the drive torque (M) to prevent damage to the press.

Dependencies are inferred from the claim text.