Multilayer Elastic Torsion Joints for Large-Angle Deflection
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Solution Overview
Problem
Existing elastic joints, such as elastomer bush bearings, cannot achieve deflection angles greater than 50° without becoming excessively long or soft, which compromises their mechanical properties and suitability for applications like wind turbine vibration absorbers.
Innovation Solution
A multilayer elastic joint design with concentric layers and a torsion stop mechanism that limits deformation to prevent overstressing, allowing for staged deflection angles up to 90° by controlling the movement of inner layers and using intermediate sheets to determine the deflection angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If elastomer bush bearings are designed to allow large deflection angles of 50° and greater, then a very thick elastomer layer is required, but this makes the bushing significantly smaller and softer on the inner diameter than on the outside diameter, compromising mechanical properties
Solution Approach 1:
The bushing is divided into multiple concentric elastomer layers separated by intermediate sheets. Each layer can deform independently within its angular limit, allowing the inner layers to accommodate large deflection angles while outer layers maintain structural integrity and mechanical properties.
Solution Approach 2:
Different regions of the bushing have different functional properties. The inner elastomer layers are designed to be softer and more compliant to accommodate large deflection angles, while the outer layers maintain higher stiffness to preserve mechanical properties. The torsion stop is positioned to allow specific angular deflection before limiting further deformation.
2Strength
If the bushing is designed much longer on the inner diameter than on the outer diameter to compensate for stiffness, then the bushing becomes disproportionately long
Solution Approach 1:
Instead of compensating for stiffness by increasing length in one dimension, the solution uses multiple concentric layers in the radial dimension. Each layer contributes to the overall stiffness while allowing angular deflection, eliminating the need for excessive bushing length.
3Ease of operation
If sliding bearings or roller bearings are used to achieve sufficient absorber amplitude, then the joints can travel long distances, but these bearings are susceptible to wear and require a larger space
Solution Approach 1:
The invention replaces traditional sliding or roller bearings with a purely elastic multilayer bushing system. The elastomer layers provide the necessary travel distance through elastic deformation rather than mechanical sliding, eliminating wear and the need for lubrication while maintaining reliability.
4Ease of operation
If elastomer having stiffness that decreases toward the outside is produced, then large deflection angles can be achieved, but the mechanical properties are lower due to the elastomer being softer on the outside
Solution Approach 1:
The bushing is segmented into multiple concentric elastomer layers, each with uniform properties. The inner layers are designed to deform at larger angles while outer layers maintain higher stiffness. This segmentation allows the system to achieve large overall deflection angles without compromising the mechanical properties of the outer layers.
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 solution enables maintenance-free, low-wear joints with large angular deflection capabilities, maintaining mechanical integrity and reducing the need for excessive length, making them suitable for applications requiring high deflection angles like wind turbine vibration absorbers.
Implementation Method 1
the innermost elastic layer is deformed the most of all the layers
Implementation Method 2
the torsion stop strikes against the innermost sheet of the layer element (1)(2) that is closest to the joint axle or the joint ball such that, after the stop strikes against the sheet, the adjacent inner elastic sheet does not undergo any further deformation
Data Source
AI summary
Novel elastic torsion stop components based on multilayer elastomer metal elements in cylindrical, conical, or spherical shape. The elastic torsion stop components are particularly suitable for use as maintenance-free and low-wear joints having a large angular spread, for example in vibration absorbers, such as in pendulum vibration absorbers for wind turbines.