Offset Bicycle Sprocket Teeth for Wear-Resistant Chain Engagement
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Solution Overview
Problem
Conventional bicycle sprockets face issues with wear and holding functionality due to the design of their teeth, which can lead to reduced service life and inefficient chain engagement.
Innovation Solution
The bicycle sprocket design incorporates alternately arranged first and second teeth with distinct radial-tooth heights and widths, allowing for improved engagement with both outer and inner link plates of the chain, reducing wear and enhancing holding functionality through optimized chain pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sprocket teeth are designed with uniform height and width, then manufacturing is simple, but wear resistance and holding function deteriorate
Solution Approach 1:
The sprocket teeth are segmented into two distinct types: first teeth with greater radial-tooth height for engaging outer link plates, and second teeth with lesser radial-tooth height for engaging inner link plates. This segmentation allows each tooth type to be optimized for its specific engagement function, improving wear resistance and holding capability while maintaining manufacturing feasibility through standardized production processes for each tooth type.
Solution Approach 2:
Different regions of the sprocket teeth are given different properties: first teeth have greater height and specific axial widths optimized for outer link plate engagement, while second teeth have lesser height and different axial widths optimized for inner link plate engagement. This local differentiation of tooth properties ensures optimal performance for each chain plate type without requiring complete redesign of all teeth.
2Reliability
If sprocket teeth are designed to engage both outer and inner link plates, then chain engagement improves, but wear increases due to improper pressure distribution
Solution Approach 1:
The sprocket employs local quality differentiation by creating two distinct tooth types with specific geometric properties. First teeth have greater radial-tooth height and axial widths optimized for engaging outer link plates, while second teeth have lesser radial-tooth height and different axial widths optimized for inner link plates. This localized optimization ensures proper pressure distribution at each engagement point, preventing excessive wear while maintaining strong holding function for both chain plate types.
Solution Approach 2:
The invention applies parameter changes by varying key geometric parameters of the teeth: radial-tooth height (greater for first teeth, lesser for second teeth), chain-engaging axial width (first width for first teeth, second width for second teeth), and tooth tip axial center plane position (offset for first teeth, at center for second teeth). These parameter variations enable each tooth type to engage its corresponding chain plate with optimal pressure distribution, reducing wear while improving holding capability.
3Strength
If first teeth have greater radial-tooth height for outer link plate engagement, then engagement strength improves, but manufacturing precision requirements increase
Solution Approach 1:
The segmentation into two tooth types with clearly defined geometric parameters allows each type to be manufactured with standardized precision requirements. First teeth are manufactured with greater radial-tooth height and specific axial widths for outer link plate engagement, while second teeth are manufactured with lesser radial-tooth height and different axial widths for inner link plate engagement. This segmentation simplifies the manufacturing process by establishing clear, repeatable specifications for each tooth type, making precision control more achievable.
Solution Approach 2:
The invention manages manufacturing precision by establishing distinct parameter ranges for each tooth type. First teeth have greater radial-tooth height with specific axial width tolerances, while second teeth have lesser radial-tooth height with different axial width tolerances. These well-defined parameter specifications enable manufacturers to control precision within achievable limits while still achieving the required engagement strength for each tooth type.
Data Source
AI summary
A bicycle sprocket has a rotational center axis. The bicycle sprocket comprises a sprocket body and sprocket teeth. The sprocket teeth include at least one first tooth and at least one second tooth. The at least one first has a first radial-tooth height. The at least one second tooth is adjacent to the first tooth and disposed on a downstream side in a rotational driving direction of the bicycle sprocket. The at least one second tooth has a second radial-tooth height. The first radial-tooth height is greater than the second radial-tooth height. The at least one first tooth includes a tooth tip having an axial center plane in an axial direction. The axial center plane of the tooth tip is offset from the axial center plane of the sprocket body in the axial direction.