Bicycle Multi-Chain Sprocket with Ribbed Support Structure
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Solution Overview
Problem
Conventional multiple sprocket wheels face challenges in achieving a balance between weight reduction and maintaining strength and stability, particularly in bicycle applications where lighter constructions are required without compromising on gear accuracy and torque transmission.
Innovation Solution
The design combines support structures with minimal wall thickness without openings and those with significantly greater wall thickness and openings, forming a web structure, where the larger wall thickness is approximately twice that of the smaller one, to achieve a lightweight yet stable configuration. This is achieved through a conical support structure with alternating tubular and disk-shaped sections and strategically placed openings to optimize weight savings and manufacturability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a one-piece construction of multiple pinion assemblies is implemented to reduce weight, then the weight of the multiple sprocket wheel is reduced, but the strength and stability of the support structure deteriorates
Solution Approach 1:
The support structure is designed with varying wall thicknesses in different regions: minimal wall thickness (e.g., 2 mm) in regions without openings for weight reduction, and significantly greater wall thickness (e.g., 4 mm) in regions with openings to maintain strength. This local differentiation allows the structure to be lightweight where possible while remaining strong where needed.
Solution Approach 2:
The support structure is divided into multiple sections with alternating tubular and disk-shaped portions, creating a stepped configuration. This segmentation allows different regions to be optimized independently - some sections have minimal wall thickness while others have greater thickness, enabling a balance between weight reduction and structural integrity.
2Weight of moving object
If openings are incorporated into the support structure to reduce weight, then the weight is reduced, but the stability and load-bearing capacity deteriorates
Solution Approach 1:
Openings are strategically placed in specific regions of the support structure where weight reduction is most beneficial, while maintaining solid construction in critical load-bearing areas. The wall thickness is increased locally around openings to compensate for the removed material, ensuring stability is maintained.
Solution Approach 2:
The support structure combines regions of minimal wall thickness with regions of greater wall thickness, creating a composite-like structure within a single component. This allows the structure to exhibit different mechanical properties in different regions - lightweight where openings are present, and stable where solid construction is needed.
3Weight of moving object
If the wall thickness is minimized to reduce weight, then the weight is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The support structure is segmented into regions with different wall thickness requirements. Minimal wall thickness is used in regions without openings, while greater wall thickness is used in regions with openings. This segmentation allows standard manufacturing tolerances to be applied to each region independently, reducing the overall manufacturing precision requirements compared to a uniform thin-walled structure.
Data Source
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AI summary
The invention relates to a multi-chain sprocket with individual sprockets of different sizes with teeth for receiving a chain and for transmitting a circumferential force introduced by the chain to a hub of a rear wheel of a bicycle, with the possibility of changing the chain from one sprocket to another by means of a shifting device, wherein an annular connecting section from one individual sprocket to the adjacent individual sprocket with a large wall thickness on the circumference has a plurality of openings, thereby creating a rib structure, while the connecting sections with a small wall thickness do not have a rib structure.