Steering Knuckle Roulette Contours Reduce Weight and Stress
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Solution Overview
Problem
Steering knuckles in motor vehicles face issues with stress concentrations and weight due to their design, particularly the 'goose neck' extension, which can lead to core breakage and increased weight from additional material needed for draft considerations in casting processes.
Innovation Solution
A steering knuckle design featuring a central portion, steering knuckle arm, upper portion, and lower portion with specific contouring and internal support structures, manufactured using a horizontal casting process that incorporates a removable core and optimized parting planes to reduce weight and stress concentrations, while allowing for efficient removal from the mold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a rectangular hollow goose neck extension is used, then weight is reduced, but stress concentrations occur in the contour and the core may break during handling
Solution Approach 1:
The patent applies curvature by transitioning from a rectangular hollow goose neck to a contoured design with rounded corners and smooth transitions. The curved contours eliminate stress concentration points while maintaining the hollow structure for weight reduction. The goose neck extension features continuous curved surfaces that distribute stress evenly throughout the structure.
2Strength
If a fully solid goose neck extension is used, then structural integrity is improved, but overall weight of the steering knuckle increases
Solution Approach 1:
The patent applies local quality by varying the cross-sectional properties of the goose neck extension along its length. The upper portion near the central portion maintains a larger cross-section for strength, while the lower portion tapers to a smaller cross-section for weight reduction. This gradient design provides structural integrity where needed while minimizing weight elsewhere.
3Ease of manufacture
If draft is added to accommodate pattern removal, then ease of manufacture is improved, but weight of the steering knuckle increases
Solution Approach 1:
The patent applies curvature to create self-drafting surfaces. The contoured goose neck extension with rounded corners and curved transitions naturally provides draft angles for pattern removal without requiring additional material. The curved surfaces allow the pattern to be withdrawn smoothly along the curvature, eliminating the need for weight-increasing draft additions.
Data Source
AI summary
A steering knuckle is used in a motor vehicle and is typically positioned adjacent a front wheel thereof. The steering knuckle includes a central portion, a steering knuckle arm, an upper portion and a lower portion. The steering knuckle arm, the upper portion and the lower portion may each be contoured with full or partial roulette contoured surfaces (i.e., surfaces defined by roulette curves), and the upper portion may transition from a hollow lower portion to a solid upper portion defining an I-beam. A dual-beam horizontal support is formed in the central portion. The steering knuckle is formed from a casting process, and the roulette curvature of the steering knuckle arm, the upper portion and the lower portion provide draft to the surfaces of the steering knuckle which are perpendicular to the parting line of the casting mold, allowing the steering knuckle to be easily removed from the casting mold.