Steering Screw Joint Curvature for Stress Relief and Load Transfer
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Solution Overview
Problem
Existing screw connections in steering systems face a trade-off between reducing stress peaks through rounded edges and maintaining load capacity and service life, as excessive rounding can diminish the functional faces necessary for force and moment transmission.
Innovation Solution
A screw connection design featuring a transition region between annular disc-shaped and cylindrical mating faces with varying radii of curvature, allowing for generous rounding that aids assembly and stress reduction while preserving functional faces for force transmission, with maximum curvature adjacent to the disc-shaped face and minimum curvature adjacent to the cylindrical face.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If edges are rounded to reduce stress peaks, then stress concentration is reduced, but the functional faces for force and moment transmission are reduced
Solution Approach 1:
The transition region is designed with non-uniform radius of curvature, where the radius varies along the transition path. This creates different local geometries: a larger radius near the annular disc-shaped face for stress reduction, and a smaller radius near the cylindrical mating face for maintaining functional contact area. This local variation in geometric quality resolves the contradiction between stress reduction and load capacity.
2Ease of operation
If large radius of curvature is used in transition region, then assembly is facilitated and stress peaks are reduced, but the functional face area is reduced
Solution Approach 1:
The transition region employs a non-uniform radius of curvature that is generously dimensioned near the annular disc-shaped face to facilitate assembly and reduce stress peaks, while gradually decreasing toward the cylindrical mating face to preserve functional face area. This localized variation in curvature radius allows large rounding benefits without sacrificing the contact area needed for force transmission.
Data Source
AI summary
A screw connection is formed between steering components, namely a push rod and a fork, in particular of a rear axle steering system. By means of a screw screwed coaxially into one of the two steering components and inserted through an opening in the other steering component, an annular disc-shaped end face of the one steering component is pressed against a likewise annular disc-shaped face of the other steering component. Furthermore, cylindrical mating faces contacting one another are formed by the steering components. In at least one of the two steering components, a transition region is formed between the annular disc-shaped face and the cylindrical mating face, which has at least two different radii of curvature.