Bicycle Sprocket Tooth Height Layout for Outward Chain Shifting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bicycle sprockets face challenges in facilitating smooth outward shifting operations due to interference between the bicycle chain and sprocket teeth, particularly when disengaging from one sprocket to a smaller adjacent sprocket, especially when the total number of teeth is odd.
Innovation Solution
The design incorporates sprocket teeth with specific height and edge configurations, including a first tooth with a shorter height than a second tooth, and additional teeth positioned without gaps in the circumferential direction, along with optimized tooth tips and edges to minimize interference during shifting, ensuring smooth operation even with odd tooth counts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the sprocket has uniform tooth heights, then the manufacturing is simpler, but the chain interference during outward shifting increases
Solution Approach 1:
The patent applies local quality by making the second tooth have a different height than other teeth. Specifically, the second tooth has a shorter tooth height to prevent interference with the chain during outward shifting operations, while other teeth maintain standard heights for normal engagement. This localized modification resolves the contradiction by sacrificing uniformity to achieve smooth shifting operation.
2Ease of operation
If the second tooth height is reduced by at least 1.0 mm, then the chain interference during outward shifting is reduced, but the tooth height variation increases
Solution Approach 1:
The patent implements local quality by selectively reducing the height of only the second tooth by at least 1.0 mm compared to other teeth. This localized dimensional change allows the chain to pass smoothly during outward shifting without interference from the second tooth, while maintaining standard tooth dimensions elsewhere for proper chain engagement.
3Ease of operation
If additional teeth are added adjacent to the first tooth, then the outward shifting operation is facilitated for odd tooth counts, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the teeth into different functional groups: the first tooth for initial chain engagement, the reduced-height second tooth for interference prevention, and additional teeth for maintaining proper chain routing. This segmentation of tooth functions allows the sprocket to handle odd tooth counts effectively while facilitating smooth outward shifting operations.
Data Source
AI summary
A bicycle sprocket comprises a sprocket body and a plurality of sprocket teeth including at least one first tooth to initially disengage with the bicycle chain in a shifting operation where the bicycle chain shifts from the bicycle sprocket to an adjacent smaller bicycle sprocket. At least one second tooth is disposed adjacent to the at least one first tooth at an upstream side of the at least one first tooth in a driving rotational direction of the bicycle sprocket. The at least one second tooth has a first tooth height. At least one third tooth is disposed adjacent to the at least one second tooth at the upstream side of the at least one second tooth. The at least one third tooth has a second tooth height longer than the first tooth height.