Bicycle Sprocket Internal Spline Layout for Correct Assembly
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Solution Overview
Problem
Current bicycle sprocket designs face challenges in efficiently facilitating smooth shifting operations and preventing incorrect assembly, which can lead to performance issues and mechanical stress.
Innovation Solution
The design incorporates a bicycle sprocket with a torque transmitting profile featuring at least ten internal spline teeth of different shapes, positioned radially inwardly, which improves strength and prevents wrong assembly by ensuring precise alignment and engagement with the sprocket teeth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional sprocket designs are used, then manufacturing is simpler, but shifting performance and assembly correctness are compromised
Solution Approach 1:
The patent applies asymmetry by providing internal spline teeth with different shapes at different positions around the inner periphery. Specifically, at least one internal spline tooth has a different shape from others, creating an asymmetric configuration that prevents incorrect assembly and ensures proper alignment with corresponding external spline teeth on the freehub body, thereby improving reliability without significantly increasing overall complexity
Solution Approach 2:
The patent implements local quality by varying the shapes of internal spline teeth at specific locations rather than making all teeth uniform. This localized differentiation allows the sprocket to provide both torque transmission and anti-reverse functionality at appropriate positions, enhancing shifting performance while maintaining manufacturing feasibility through targeted design modifications
2Strength
If sprocket teeth are made stronger, then mechanical stress resistance improves, but weight increases
Solution Approach 1:
The patent applies segmentation by dividing the torque transmission function across multiple internal spline teeth with different shapes distributed around the inner periphery. This segmentation allows the load to be distributed among several teeth rather than concentrated in one large tooth structure, providing sufficient strength while maintaining a lightweight design through efficient load distribution
Solution Approach 2:
The patent utilizes composite material principles by integrating the sprocket body with internal spline teeth of varying shapes that work together as a unified structure. The combination of different tooth shapes creates a composite functional architecture that optimizes both strength and weight, allowing the sprocket to withstand mechanical stress without requiring excessive material
3Reliability
If internal spline teeth have different shapes, then wrong assembly is prevented, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies asymmetry by providing internal spline teeth with different shapes at different positions around the inner periphery. Specifically, at least one internal spline tooth has a different shape from others, creating an asymmetric configuration that prevents incorrect assembly and ensures proper alignment with corresponding external spline teeth on the freehub body, thereby improving reliability without significantly increasing overall complexity
Solution Approach 2:
The patent implements parameter changes by varying the geometric parameters of internal spline teeth at different positions. By changing tooth shape parameters locally rather than uniformly across all teeth, the design achieves anti-reverse functionality while maintaining manufacturing precision through controlled parameter variations that are feasible with standard manufacturing processes
Data Source
AI summary
A bicycle sprocket comprises a sprocket body, a plurality of sprocket teeth, and a torque transmitting profile. The sprocket body has an outer periphery and an inner periphery positioned radially inwardly from the outer periphery with respect to a rotational center axis of the bicycle sprocket. The plurality of sprocket teeth is disposed on the outer periphery of the sprocket body. The torque transmitting profile is positioned around the inner periphery of the sprocket body. The torque transmitting profile includes at least ten internal spline teeth. The at least ten internal spline-teeth include at least one first internal spline-tooth, at least one second internal spline-tooth and at least one third internal spline-tooth. The at least one internal first spline-tooth, the at least one second internal spline-tooth and the at least one third internal spline-tooth are different in shape from each other.