Cycle Wheel Hub Cap Retention Using a Polygonal Metal Pin
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Solution Overview
Problem
Existing hub axle cap retention systems face challenges in reproducibility and stability, leading to difficulties in assembly, disassembly, and risk of cap separation during wheel attachment and detachment.
Innovation Solution
A hub design featuring a metal pin with a polygonal profile that provides a radial retention element, supporting the cap on both the shaft and cap surfaces, ensuring secure and distributed retention force through multiple contact points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If O-rings are placed in a groove to retain the cap on the shaft, then the cap retention is improved, but the manufacturing precision and assembly difficulty are worsened due to sensitivity to diameter variations
Solution Approach 1:
The invention changes the retention mechanism from relying on precise diameter relationships (O-rings in grooves) to using a deformation-based metal pin that adapts to dimensional variations. The pin's elastic deformation allows it to accommodate a range of shaft and cap diameter values while maintaining reliable retention, thus decoupling retention reliability from manufacturing precision requirements.
Solution Approach 2:
The metal pin applies localized retention force at specific contact points rather than relying on uniform circumferential pressure from an O-ring. This localized approach concentrates the retention function in a small elastic element that can deform to accommodate dimensional variations, reducing sensitivity to overall diameter tolerances.
2Reliability
If the cap is retained using prior art methods, then the cap stays in place during handling, but the assembly and disassembly processes become difficult and time-consuming
Solution Approach 1:
The metal pin is pre-installed in the shaft in a relaxed state before cap assembly. During assembly, the pin automatically deforms to engage the cap without requiring additional retention components or complex assembly steps. This preliminary positioning of the retention element simplifies the overall assembly process while ensuring reliable retention.
Solution Approach 2:
The invention extracts the retention function from complex multi-component systems (O-rings, grooves, interference fits) and concentrates it in a single simple metal pin element. This simplification reduces assembly complexity and time while maintaining retention reliability.
3Reliability
If tight tolerances are used for shaft and plug diameters to ensure retention, then the retention force is improved, but the manufacturing cost and complexity increase
Solution Approach 1:
The invention changes the retention mechanism from relying on precise diameter relationships (O-rings in grooves) to using a deformation-based metal pin that adapts to dimensional variations. The pin's elastic deformation allows it to accommodate a range of shaft and cap diameter values while maintaining reliable retention, thus decoupling retention reliability from manufacturing precision requirements.
Data Source
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AI summary
Hub (1) for a cycle wheel intended to be fixed to a frame element of a cycle comprising a central shaft (3) around which is rotatably mounted a hub body (11) and at least one cap (2) placed at the end of said shaft, said cap (2) comprising a first cylindrical wall (21) intended to slide against a second cylindrical wall (32) formed on the shaft (3), an inner annular surface (5) and an outer annular surface (6) being defined on the cap (2) and the shaft (3), so as to provide a radial space (7) between them, said hub (1) further comprising a retention element (4) of the cap (2) on the shaft (3) placed in said radial space (7), said retention element (4) being constituted by a metal pin of which at least a portion is in simultaneous contact with the central shaft and the cap.Preferably, at least a portion of the pin is supported at both ends by the outer annular surface (6) and in contact with the inner surface at an intermediate zone located between said two ends. The pin has a polygonal profile.