Extruder Coupling Element With Built-In Torsional Break Point
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Solution Overview
Problem
Existing clutch solutions for double snail extruders face challenges in protecting components from overload due to limited axle spacing, which restricts the design of conventional clutches that require additional radial installation space.
Innovation Solution
A clutch element with a connecting area featuring extensively distributed and radially running holes or an extensive weld seam, which acts as a weakened area that fails under torsional overload, thereby protecting other system components without requiring additional axial space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional clutch solutions are used to protect components from overload, then component protection is achieved, but radial installation space is required which is not available in twin-screw extruders
Solution Approach 1:
The invention merges the clutch function directly into the coupling element by integrating a weakened region (shear section) into the coupling structure itself. This eliminates the need for separate clutch components and their associated radial installation space, while maintaining overload protection functionality through the predefined failure point in the coupling element.
Solution Approach 2:
The invention extracts the clutch functionality from separate components and embeds it within the coupling element through a specifically designed weakened region. This allows the overload protection mechanism to be contained within the existing coupling footprint, removing the need for additional radial space that conventional clutch solutions would require.
2Manufacturing precision
If the center distance between extruder screws is maintained for proper extrusion geometry, then extrusion quality is ensured, but the outer diameter of gearbox output shafts is limited resulting in high torque density
Solution Approach 1:
The invention prepares for potential overload conditions by pre-defining a weakened region in the coupling element that will fail at a controlled torque level. This preliminary design feature ensures that when overload occurs, the coupling element breaks at the predetermined shear section, protecting the high-torque-density gearbox output shafts and maintaining extrusion quality by preventing catastrophic failures.
3Reliability
If the coupling element is designed with a weakened region for overload protection, then component protection is achieved, but the coupling structure becomes more complex
Solution Approach 1:
The invention combines the clutch function with the coupling element structure, creating a unified component rather than separate parts. The weakened region is integrated into the coupling element's geometry, eliminating the need for additional clutch components and reducing overall device complexity while maintaining reliable overload protection.
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
The clutch element effectively protects the extruder system components from overload by providing a targeted breakage point within the clutch itself, allowing for a more compact design and enabling retrofitting of existing systems without additional installation space.
Implementation Method 1
The connecting region, via the bores or the weld seam, has a reduced fracture moment under torsional loading compared to an adjacent structural region of the receiving bushings
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
Coupling element 10 for connecting each extruder screw 14, 16 to a drive unit 12 of a twin-screw extruder 2, with two receiving bushings 18, 20 connected to each other in a connection area 22, wherein the first receiving bushing 18 is provided for receiving a shaft end of the drive unit 12 and the second receiving bushing 20 for receiving one of the extruder screws 14, 16. The connection area 22 has a plurality of circumferential bores 24 or a circumferential weld seam 26. The connection area 22 forms a predetermined breaking point that fails in the event of overload and thus protects the other system components.