Bottom Drive Press Ram Control for Bending Stress Reduction
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Solution Overview
Problem
Presses with bottom drive face challenges in efficiently managing complex forces and achieving precise control over large effective ranges, leading to inefficiencies and limitations in processing capabilities, particularly in large presses and press lines, due to issues with bending stress, deflection, and the transmission of eccentric forces.
Innovation Solution
A control and regulating device is implemented to record and process data from various sources within the press system, allowing for a differentiated and variable force profile of the ram, enabling it to cover a larger effective range and adapt to machining requirements, using a combination of data acquisition and evaluation methods to influence the ram's movement and force distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the ram is driven by tie rods/connecting rods acting laterally on the tappet, then the drive transmission is achieved, but bending stress and deflection of the tappet increase
Solution Approach 1:
The patent inverts the conventional lateral action of tie rods on the tappet by using drawbars that act vertically from above. The drawbars are connected to the ram and extend downward to connect to the base, creating a vertical force transmission path that eliminates the bending moment caused by lateral lateral forces. This inversion of the force application direction fundamentally resolves the bending stress problem while maintaining drive transmission capability.
Solution Approach 2:
The patent extracts the force transmission function from the lateral tie rod mechanism and relocates it to a vertical drawbar system. By separating the drive transmission function from the conventional lateral action, the design eliminates the source of bending stress and deflection while preserving the essential power transmission capability through the vertical drawbar-path.
2Force
If the line of action of forces acts off-center on the tappet, then force transmission is achieved, but the forces are difficult to transmit efficiently
Solution Approach 1:
The patent employs asymmetric force application by positioning the drawbars vertically above the tappet rather than laterally. This asymmetric arrangement creates a direct vertical force path that passes through the center of gravity of the tappet, eliminating eccentric forces and their associated energy losses. The asymmetric placement of drawbars above the tappet fundamentally changes the force transmission efficiency.
3Stability of the object's composition
If a stand construction is used to absorb forces, then structural stability is improved, but the press frame becomes more complex and larger
Solution Approach 1:
The patent extracts the force absorption function from the complex stand construction and relocates it to the base. By positioning the drawbars to connect directly to the base, the base assumes the role of the force absorption structure, eliminating the need for separate stand constructions. This extraction simplifies the overall press frame while maintaining structural stability.
Solution Approach 2:
The patent merges the force absorption function with the base structure, combining what were previously separate functional elements (stands for force absorption and base for support) into a unified base structure. This merging eliminates the complexity of separate stand constructions while achieving the same force absorption capability, thereby simplifying the press frame design.
4Force
If the press is designed for high pressing forces, then processing capability is improved, but the number of moving machine elements increases
Solution Approach 1:
The patent extracts the force transmission function from complex multi-element mechanisms and consolidates it into a simplified drawbar system. By using direct vertical drawbars connected to the base, the design achieves high pressing forces with minimal moving parts, eliminating the need for multiple intermediate transmission elements while maintaining high force capability.
Data Source
Figure 1
Figure 2a~2b
Figure 3
AI summary
In a press (1) having a bottom drive, a plunger (1.1) executing a stroke (h) and accommodating at least one upper tool part (1.2), tie rods (2.1.2) acting on the plunger (1.1) which in each case form a drive train (2.1.4) of a drive device (2) having a motor or servomotor (2.1.1), and a lower tool part (3.2) arranged on a sub-structure (3), in which the plunger (1.1) with the upper tool part (1.2) acts on the workpiece (5) to be processed, the effective forces act in a differentiated manner and in a greater effective range if, by means of an open-loop and closed-loop control device (4), values from operating states in the system of the press (1) are recorded during the processing of the workpiece (5) and are evaluated in accordance with the function (Formula (I)) to form data, and the movement of the plunger is used for x, so that the press (1) can be operated under open-loop or closed-loop control in accordance with a force system required for the workpiece (5).