Bicycle Sprocket Teeth with Variable Axial Widths
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Solution Overview
Problem
Bicycle sprockets with uniform tooth thickness lead to gaps between outer and inner links of the chain, causing the chain to easily separate from the sprocket, especially when riding on rough terrain.
Innovation Solution
Designing a bicycle sprocket with teeth of different axial widths, where the first tooth has a greater axial width for engaging with outer links and a second tooth with a lesser axial width for engaging with inner links, using a combination of metallic and resin materials for the teeth and projecting members, respectively, and attaching these members via integral molding or adhesive processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uniform tooth thickness is used on the sprocket, then the manufacturing is simple and consistent, but gaps occur between the chain links and teeth causing the chain to easily separate from the sprocket
Solution Approach 1:
The sprocket teeth are designed with different axial widths to match different chain link types. Specifically, teeth engaged with outer links have a greater axial width than teeth engaged with inner links. This local variation in tooth geometry ensures proper engagement with both inner and outer links, preventing chain separation while maintaining overall sprocket functionality.
2Reliability
If different axial widths of teeth are used to prevent chain separation, then chain engagement reliability improves, but the manufacturing complexity and precision requirements increase
Solution Approach 1:
The patent implements local quality by creating teeth with different axial widths at specific locations on the sprocket. The teeth that engage with outer links are made with a greater axial width, while teeth engaging with inner links have a standard width. This localized differentiation ensures reliable chain engagement without requiring the entire sprocket to be manufactured with high precision variations.
Data Source
AI summary
A bicycle sprocket basically includes a sprocket main body, a plurality of teeth and at least one projecting member. The teeth are disposed along a circumferential direction on a radially outer side of the sprocket main body. The teeth include at least one first tooth and at least one second tooth. The at least one projecting member protrudes from an axial surface of the at least one first tooth. The at least one projecting member is a different material from the teeth. The at least one projecting member and the at least one first tooth define a first chain engaging tooth width for engaging with an outer link of a bicycle chain. The at least one second tooth defines a second chain engaging tooth width for engaging with an inner link of the bicycle chain. The first chain engaging tooth width is greater than the second chain engaging tooth width.