Chainring Bevel Geometry for Roller Chain Retention
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Solution Overview
Problem
Traditional chainrings face issues with roller chain retention due to varying approach angles as different rear gears are selected, leading to potential disengagement and retention problems.
Innovation Solution
The chainring design incorporates bevels that align with the roller chain links, eliminating the need for clocking and enhancing retention by matching the bevels of the chainring with those of the roller chain, thereby maintaining proper alignment and reducing misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional chainring design is used, then manufacturing is simple, but chain retention deteriorates due to varying approach angles
Solution Approach 1:
The chainring incorporates bevels at specific locations (where the roller chain contacts the chainring) with specific angles (matching the approach angles of the roller chain), while the rest of the chainring maintains a traditional simple structure. This localized modification improves chain retention without significantly increasing overall device complexity.
Solution Approach 2:
The invention changes the geometric parameters of the chainring by adding bevels with specific angles that match the roller chain approach angles. This parameter modification allows the chainring to accommodate varying approach angles when different rear gears are selected, thereby improving chain retention reliability.
2Reliability
If bevels are added to the chainring, then chain retention improves, but manufacturing complexity increases
Solution Approach 1:
Instead of modifying the entire chainring structure, only localized bevels are added at the specific contact points where the roller chain interacts with the chainring. This minimizes the additional manufacturing complexity while achieving the desired improvement in chain retention.
3Object-generated harmful factors
If bevels are added to the chainring, then debris shedding improves, but device complexity increases
Solution Approach 1:
The bevels are strategically positioned at the contact points between the roller chain and chainring, where debris tends to accumulate. These localized bevels create channels that facilitate debris shedding without requiring a complete redesign of the entire chainring structure.
Data Source
AI summary
A chainring is disclosed. The chainring includes a plurality of teeth about the outer perimeter of the chainring; and a chain retention feature at a root of one or more of the plurality of teeth and traversing at least a portion of a circumference of the chainring, the chain retention feature to align with at least a portion of a roller chain and assist in a retention of the roller chain on the chainring.