Rear Sprocket Spline Layout for Bicycle Drivetrain Durability
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Solution Overview
Problem
Current bicycle rear sprocket assemblies with nine or fewer internal spline teeth face challenges in durability and material selection, as they do not effectively distribute rotational forces, limiting the choice of materials without compromising durability.
Innovation Solution
The bicycle rear sprocket assembly incorporates at least ten internal spline teeth, with varying pitch angles and sizes, and a combination of spline shapes and sizes to enhance durability and allow for broader material selection, while also expanding the gear range through the inclusion of sprockets with more teeth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of internal spline teeth is increased to at least ten, then durability is improved and rotational force per tooth is reduced, but device complexity increases
Solution Approach 1:
The drive train power transmission is segmented across multiple spline teeth (at least ten) distributed around the sprocket circumference. Each spline tooth independently transmits a portion of the total rotational force, distributing the mechanical load and preventing any single tooth from becoming a failure point, thereby improving durability without requiring a complete redesign of the power transmission system.
2Adaptability or versatility
If the number of internal spline teeth is increased to at least ten, then material selection freedom is improved, but manufacturing complexity increases
Solution Approach 1:
The invention changes the numerical parameter of spline tooth count from nine or fewer to at least ten, which fundamentally alters the stress distribution characteristics. This parameter change enables the use of a broader range of materials (including lighter or less traditionally durable materials) because the reduced stress per tooth allows materials with lower inherent strength to still meet durability requirements, thereby expanding material selection freedom.
3Adaptability or versatility
If sprockets with varying pitch angles and sizes are used, then gear range is expanded, but manufacturing precision requirements increase
Solution Approach 1:
The invention employs asymmetric design by varying the pitch angles and sizes of different sprockets within the assembly. Each sprocket can have unique dimensional characteristics optimized for specific gear ratios, allowing expansion of the overall gear range. The asymmetric configuration enables tailored performance for different riding conditions while the standardized spline interface maintains manufacturing feasibility.
Data Source
AI summary
A bicycle rear sprocket assembly comprises at least one sprocket. The at least one sprocket includes at least ten internal spline teeth configured to engage with a bicycle hub assembly.