Composite Bicycle Chainring Segmentation for Weight and Noise
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Solution Overview
Problem
Bicycle chain engaging gears contribute significantly to the weight and noise of bicycles, despite recent improvements in material science, necessitating a solution for reduced weight and noise reduction.
Innovation Solution
A composite bicycle chainring design comprising a first and second member, where the second member is fixedly attached to reinforce the first member without obstructing chainring attachment openings, using non-metallic filler material and tubular fastening members for assembly, enhancing weight reduction and noise dampening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a traditional single-piece chainring is used, then the structure is simple and strong, but the weight is high and noise transmission is significant
Solution Approach 1:
The chainring is divided into two separate members: a first member containing the gear teeth and a second member acting as a reinforcement ring. This segmentation allows each component to be optimized independently - the first member can be made lighter while the second member provides structural reinforcement, thereby reducing overall weight without compromising strength.
Solution Approach 2:
The chainring combines two different members made from potentially different materials or structures. The first member and second member are fixedly attached to form a composite structure that leverages the advantages of both components, achieving weight reduction while maintaining or enhancing structural integrity compared to a traditional single-piece design.
2Object-affected harmful factors
If a traditional single-piece chainring is used, then the manufacturing process is simple, but noise transmission during riding is significant
Solution Approach 1:
By segmenting the chainring into two members that are fixedly attached, the structure creates natural decoupling of vibration and noise pathways. The interface between the first and second members can be designed to dampen noise transmission, reducing the harmful noise effect while the separate manufacturing of components may actually simplify certain manufacturing steps.
Solution Approach 2:
The second member acts as an intermediary element between the first member and the external environment. This intermediate structure can be designed to absorb or dampen vibrations and noise, reducing noise transmission during riding while being manufactured as a separate component that is then attached to the first member.
3Strength
If the second member is added to reinforce the first member, then the structural strength is improved, but the device complexity increases
Solution Approach 1:
The reinforcement function is segregated into a separate second member that is fixedly attached to the first member. This allows the reinforcement structure to be optimized independently - the second member can be designed with specific thickness, material properties, or geometric features to provide the needed strength without adding unnecessary complexity to the gear teeth portion of the first member.
Solution Approach 2:
The first member and second member are merged through fixed attachment to form an integrated composite chainring structure. This merging provides the combined benefits of both components - the gear functionality of the first member and the reinforcement of the second member - creating a unified structure that is stronger than either component alone while maintaining manageable complexity through their modular design.
Data Source
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AI summary
A bicycle chainring (14,114,214,314) is formed from a first member (28,128,228,328) and an second member (30,130,230,330). The first member includes a center rotational axis, a crank attachment portion (40) with a plurality of chainring attachment openings (52) and an annular tooth portion (42) with a plurality of chain engaging gear teeth (58). The second member (30,130,230,330) disposed around the center rotational axis (C) and is fixedly attached to overlie at least one of the crank attachment portion and the annular tooth portion to reinforce the first member without obstructing access to the chainring attachment openings.