Servo Crank Press Operation Using Ram Inertia for Full Pressing Force
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Solution Overview
Problem
Existing methods for operating presses, such as crank presses, face challenges in efficiently utilizing energy and reducing costs, particularly in achieving high output with a small servo drive and converter, which are essential for cost-effectiveness.
Innovation Solution
The method involves a servo drive and a mass system between the servo drive and the workpiece, where the mass system, comprising a ram and drive shaft, is accelerated by the servo drive to provide at least 100% of the nominal pressing force, allowing the servo drive to be dimensioned smaller compared to the nominal pressing force, and kinetic energy is reused across cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the servo drive is dimensioned to provide 100% of the nominal pressing force, then the pressing force is sufficient for the forming process, but the servo drive and converter become expensive and large
Solution Approach 1:
The patent applies dynamics by accelerating the mass system (ram and drive shaft) before the forming process using the servo drive, then utilizing the stored kinetic energy during forming. This dynamic approach allows the servo drive to provide maximum force only temporarily during acceleration, rather than continuously at 100% capacity, enabling cost-effective dimensioning while maintaining sufficient pressing force through the combination of drive force and inertial energy.
2Force
If the servo drive provides maximum power continuously, then the pressing force requirement is met, but energy efficiency decreases and costs increase
Solution Approach 1:
The patent implements periodic action by alternating between acceleration phases (where the servo drive provides power to build kinetic energy) and forming phases (where the stored kinetic energy is utilized). This periodic cycle allows the servo drive to operate at high power only during brief acceleration intervals rather than continuously, significantly improving energy efficiency while still delivering the required pressing force when needed.
Solution Approach 2:
The mass system serves itself by storing kinetic energy during acceleration and then releasing this energy during the forming process. This self-service mechanism reduces the continuous power demand on the servo drive and electrical converter, allowing for more cost-effective component sizing while maintaining energy efficiency through the reuse of kinetic energy within the system.
3Use of energy by moving object
If a flywheel energy storage device is added, then energy efficiency improves, but device complexity and cost increase
Solution Approach 1:
The patent applies multi-functionality by making the existing mass system (ram and drive shaft) serve dual purposes: as functional components of the press and as the energy storage medium. By utilizing the inherent mass of these components for kinetic energy storage rather than adding a separate flywheel, the system achieves energy storage efficiency improvements without increasing device complexity or requiring additional components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables cost-effective components and continuous operation by leveraging kinetic energy stored in the mass system, reducing the need for full electrical power during forming processes and allowing for smaller, more economical servo drives and converters.
Implementation Method 1
the mass of the mass system is accelerated by the servo drive before the forming process in such a way that at least 100% of the nominal pressing force is available during the forming process
Data Source
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AI summary
The invention relates to a method for operating a press with at least 80% of its nominal pressing force, in particular a crank press for forming, in particular for forging workpieces such as, in particular, a forging crank press, wherein the press comprises a servo drive and a mass system that is arranged between the servo drive and a workpiece and moves during operation of the press, wherein a mass of the mass system is formed at least by a ram and at least by a drive shaft, wherein the mass system is driven at least at times by the servo drive, wherein at most 80% of the nominal pressing force for a forming operation is provided by the servo drive, and wherein the mass of the mass system is accelerated by the servo drive before the forming operation such that, during the forming operation, at least 80% of the nominal pressing force is available.