Bicycle Rear Sprocket Assembly Recess Coupling
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Solution Overview
Problem
Current bicycle rear sprocket assemblies face challenges in maintaining effective coupling strength between sprockets and the sprocket support, leading to potential weight and structural inefficiencies.
Innovation Solution
The bicycle rear sprocket assembly incorporates a design with recesses and support arms that enhance surface area contact between sprockets and the sprocket support, utilizing adhesive attachment and specific material choices like aluminum to improve strength and reduce weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional coupling methods are used between sprocket and sprocket support, then structural simplicity is maintained, but coupling strength is insufficient
Solution Approach 1:
The sprocket body is divided into multiple segments with recesses that receive support arms, creating a modular coupling structure. This segmentation allows the sprocket to be attached to the sprocket support through multiple discrete attachment points, significantly improving coupling strength while maintaining relative structural simplicity.
Solution Approach 2:
The invention transitions from a traditional single-plane coupling to a multi-dimensional attachment structure. Support arms extend radially inward to engage recesses in the sprocket body, adding a radial dimension to the coupling. This multi-dimensional approach enhances coupling strength by distributing forces across multiple spatial dimensions.
2Strength
If more material is used to increase coupling strength, then strength is improved, but weight increases
Solution Approach 1:
The invention employs composite construction where the sprocket body, support arms, and sprocket support are made from different materials optimized for their specific functions. The sprocket body may use high-strength aluminum alloy or titanium, while support arms use materials optimized for fatigue resistance. This composite approach achieves high coupling strength with reduced weight compared to traditional homogeneous metal constructions.
Solution Approach 2:
Rather than uniformly increasing material throughout the assembly, the invention applies high-strength materials and complex geometries only where needed - specifically in the support arms and recess areas where coupling strength is critical. Other areas of the sprocket body can use lighter materials, achieving optimal strength-to-weight ratio through localized material optimization.
3Strength
If surface area contact is increased between sprocket and sprocket support, then coupling strength is improved, but manufacturing complexity increases
Solution Approach 1:
The large surface area contact is achieved through segmentation into multiple discrete support arms that each engage with recesses in the sprocket body. This segmentation breaks down the complex manufacturing of a single large contact surface into multiple simpler, standardized arm and recess components that are easier to manufacture and assemble.
Solution Approach 2:
The recesses in the sprocket body are pre-formed during sprocket manufacturing, creating ready-to-receive features for the support arms. This preliminary action eliminates the need for complex post-assembly operations to create the contact surfaces, as the geometric features are already prepared in advance, simplifying the overall manufacturing process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design maintains or improves coupling strength while reducing weight, enhancing the structural integrity and efficiency of the bicycle rear sprocket assembly.
Implementation Method 1
at least one of the first sprocket and the second sprocket is attached to the sprocket attachment part by adhesive
Data Source
AI summary
A bicycle rear sprocket assembly comprises a first sprocket, a second sprocket, and a sprocket support. The first sprocket includes a first sprocket body and a plurality of first sprocket teeth. The first sprocket body has at least one first recess. The second sprocket includes a second sprocket body and a plurality of second sprocket teeth. The sprocket support is configured to engage with a bicycle hub assembly. The sprocket support includes a sprocket attachment part. The first sprocket and the second sprocket are attached to the sprocket attachment part. The sprocket attachment part is at least partly provided in the at least one first recess to transmit a rotational force between the first sprocket and the sprocket support.