Bicycle Sprocket Tooth Width Optimization
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Solution Overview
Problem
Bicycle sprockets face challenges in maintaining effective chain engagement and holding performance, particularly when the bicycle chain is inclined, leading to potential interference and instability.
Innovation Solution
The design of the bicycle sprocket features chain-driving teeth with specific width and positioning configurations, including a first tooth with a wide chain-engaging surface and a second tooth with a smaller width, optimized to reduce inclination angles and improve chain-holding performance by increasing the chain-engaging surface area and minimizing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first tooth has a larger chain-engaging width to increase chain engagement area, then the chain-holding performance is improved, but the second tooth may interfere with the inner link plate when the chain is inclined
Solution Approach 1:
The sprocket teeth are designed with different chain-engaging widths tailored to specific positions. The first tooth has a larger width (first maximum chain-engaging width) to provide enhanced engagement area for improving chain-holding performance, while the second tooth has a smaller width (second maximum chain-engaging width smaller than inner link space) to prevent interference with the inner link plate. This localized differentiation resolves the contradiction by optimizing each tooth's dimensions for its specific functional requirement.
Solution Approach 2:
The chain-driving teeth are segmented into multiple teeth with different geometric characteristics. Rather than using uniform teeth throughout, the invention divides the teeth into at least a first tooth and a second tooth with distinct width parameters. This segmentation allows each tooth to be optimized independently - the first tooth for maximum engagement area and the second tooth for clearance - thereby resolving the contradiction between engagement performance and interference prevention.
2Area of moving object
If the first tooth width is increased to 70% or more of the first maximum chain-engaging width, then the chain-engaging surface area is increased, but the sprocket complexity increases
Solution Approach 1:
The invention applies parameter changes by specifically defining the first tooth width as 70% or more of the first maximum chain-engaging width. This quantitative parameter specification optimizes the chain-engaging surface area to improve chain-holding performance while maintaining manufacturability. The precise parameter definition resolves the contradiction by establishing an optimal range that balances engagement area with design simplicity.
Data Source
AI summary
A bicycle sprocket comprises a sprocket body and a plurality of chain-driving teeth. The plurality of chain-driving teeth comprises a first tooth and a second tooth. The first tooth has a first maximum chain-engaging width defined in an axial direction parallel to the rotational center axis. The second tooth has a second maximum chain-engaging width defined in the axial direction. The first tooth has a first width defined in the axial direction. The first width is defined at a reference position radially outward spaced apart from a center point of a reference line by 1.5 mm. The reference line is defined to connect centers of neighboring pins of the bicycle chain engaged with the plurality of chain-driving teeth when viewed from the axial direction. The first width is 70% or more of the first maximum chain-engaging width.