Flywheelless Toggle Press Ram Stiffness and Horizontal Force Reduction
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Solution Overview
Problem
Existing mechanical presses for fine blanking, forming, and embossing face challenges with reduced stiffness at top dead center, increased massiveness of the machine frame, and higher drive power requirements due to flywheel omission, leading to ram wear and inefficient power transmission.
Innovation Solution
The stroke axis of the ram is aligned with the fixed bearing of the triangular connecting rod, with the toggle lever drive positioned below the ram and fixed bearings located on the foot side of the O-frame, utilizing three-phase synchronous motors with identical path-time characteristics to optimize power transmission and reduce massiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the fixed bearing for the toggle lever is located above the press ram, then the material has enough time for plastic flow at the bottom dead center, but the horizontal force components acting on the ram increase, leading to increased ram wear and higher drive power requirements
Solution Approach 1:
The patent inverts the conventional arrangement by locating the fixed bearing for the toggle lever below the press ram instead of above it. This inversion changes the geometry of the toggle lever mechanism, allowing the articulated arms to reach a largely extended position at top dead center, thereby minimizing horizontal force components while still providing adequate plastic flow time at bottom dead center.
2Volume of moving object
If the fixed bearing for the eccentric shaft is arranged close to the ram, then the toggle lever can be compact, but the rigidity and power transmission to the ram deteriorate due to non-aligned axes
Solution Approach 1:
The patent employs asymmetric arrangement of the fixed bearings, positioning them on the foot side of the O-frame rather than symmetrically above the ram. This asymmetric configuration allows the stroke axis of the ram to be arranged on the axis of the fixed bearing for the triangular connecting rod, achieving both compactness and aligned axes for optimal power transmission.
3Stability of the object's composition
If the machine frame is made more massive to handle increased horizontal forces, then the structural stability improves, but the overall massiveness and drive power requirements increase
Solution Approach 1:
By inverting the toggle lever drive arrangement and positioning fixed bearings on the foot side of the O-frame, the patent minimizes horizontal force components acting on the ram. This reduction in horizontal forces allows the machine frame to be less massive while maintaining adequate structural stability, as the forces transmitted to the frame are reduced.
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 configuration enhances stiffness at top dead center, minimizes horizontal force components, reduces ram wear, and decreases the massiveness of the machine frame while maintaining efficient drive power, allowing for optimal power transmission without significant losses.
Implementation Method 1
flywheelless three-phase synchronous motors
Implementation Method 2
eccentric shafts whose opposite shaft ends are connected to one another in a non-rotatable manner
Implementation Method 3
toggle lever drive, of which an approximately equilateral active triangle, has two articulation points arranged one above the other
Data Source
Figure 1
Figure 2
Figure 3a
AI summary
The invention relates to a mechanical press for fine blanking, forming and/or embossing of workpieces, comprising a machine frame (2) consisting of a head piece (39) and an O-frame (29), a ram (3) guided vertically on a lifting axis (HU) in the O-frame (29), and a flywheelless toggle lever drive arranged below the ram (3).A connecting rod (8) with an approximately equilateral effective triangle has two pivot points (22; 23) arranged one above the other, the lower pivot point (23) pivoting about a fixed bearing (FL1) arranged at the foot end of the O-frame (29) via a disc-shaped lower joint arm (26), and the upper pivot point (25) associated with the tappet (3) assumes an extended position with the lower disc-shaped joint arm (24) at top dead center (TDC) relative to the stroke axis (HU), the fixed bearing (FL1) lying on the stroke axis (HU) of the tappet (3), and two eccentric shafts (6) aligned with their axes and mounted in further fixed bearings (FL2) are associated with the connecting rod (8), the opposite ends (36) of which are connected to flywheelless three-phase synchronous motors (34; 35) via a planetary gear (37) for their simultaneous parallel drive, the motors being mounted on The same distance-time parameters can be set using a computer (38) connected to the motors (34;35).