Power-Split Press Drive for Economic Production

Abstract

The servo press technology is used in industrial production for innovative and economic metal forming. The path-time-characteristic of the ram of servo presses can be adapted to individual requirements of various forming processes. To achieve a high dynamic, the rotary inertia of the drive train should be as low as possible. Thus, a flywheel is not suitable to provide the energy required for both, the forming process as well as the ram kinematic. Hence the eccentric shaft is driven by the electric motor only. As a consequence, the press force has to be provided completely via the torque of the servomotor. High investment costs resulting from the required size of the drive components is a challenge to be conquered. This pushes the costs for the drive components.Another challenge is the unbalanced power consumption of the servomotor. Energy-converting and energy-storing systems are essential to compensate the power peaks resulting from the forming process and inertia forces. Nevertheless, these systems are expensive and reduce the energy efficiency of the press. Facing these challenges, a novel and innovative drive concept for eccentric presses is being developed at the Institute of Forming Technology and Machines (IFUM). These drive concept base on mechanical and electrical power split and can possibly eliminate any disadvantages of conventionally servo presses. The function, the control concept and first steps of the realization of the power-split press drive are presented in this paper.