Pivot Link Assembly With Varying Shaft Dimensions
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Solution Overview
Problem
Aviation pivot connection assemblies suffer from early damage at the edges of bores due to large radial forces, leading to maintenance needs and weight concerns that impact aircraft performance.
Innovation Solution
A pivot connection assembly with a hollow shaft featuring varying radial dimensions and a ring of varying thickness in the bore of the connection part, addressing both the cause and consequence of damage by reinforcing the shaft and bore edges, respectively, while minimizing overall weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shaft and connection parts are designed with uniform dimensions throughout, then the manufacturing is simpler and weight is reduced, but damage occurs at the bore edges due to stress peaks from radial forces
Solution Approach 1:
The shaft is designed with varying wall thickness along its length, with thicker sections at locations experiencing higher radial forces (such as near the radial plane) and thinner sections where forces are lower. This non-uniform thickness distribution provides local reinforcement exactly where needed to prevent bore edge damage, while avoiding unnecessary weight and complexity elsewhere in the structure.
Solution Approach 2:
The connection parts are segmented into multiple sections with different dimensional characteristics. Specifically, the bore edges are reinforced with thicker material or strengthening features at critical locations, while other portions maintain thinner dimensions. This segmentation allows the structure to withstand localized stress peaks without requiring uniform reinforcement throughout the entire component.
2Reliability
If reinforcement is added to prevent damage at bore edges, then reliability improves, but the weight of the assembly increases
Solution Approach 1:
Rather than adding uniform reinforcement throughout the shaft and connection parts, the design implements localized thickening only at specific positions where radial forces generate stress peaks. The wall thickness varies along the shaft length, providing reinforcement precisely where needed to prevent bore edge damage while keeping other areas lightweight.
Solution Approach 2:
The structural parameters (wall thickness, bore diameter, material distribution) are varied continuously or stepwise along the length of the shaft and connection parts. This parameter optimization ensures that material is concentrated in regions of high stress while minimizing material usage in low-stress regions, achieving the best possible balance between damage resistance and weight reduction.
Data Source
AI summary
The invention relates to a pivot connection type assembly comprising a shaft and first and second connection parts, each receiving the shaft so as to enable them to pivot relative to each other, the first connection part being arranged axially between a first end of the shaft and a radial plane, while the second connection part is arranged axially between said radial plane and the other end of the shaft. The shaft is hollow and includes an inside section that presents a radial dimension at least in a first axial plane and over a first segment of the shaft extending axially between the first end and the radial plane, which radial dimension varies, decreasing on axially approaching the radial plane. The assembly includes a ring interposed radially between the shaft and a bore of the first connection part, and presenting radial thickness that varies.