Direct-Mount 2X Chainring Assembly With Nested Spline Alignment
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Solution Overview
Problem
Traditional chainring assemblies face challenges in balancing performance requirements such as speed and vehicle clearance, often necessitating different sizes and configurations that are not easily accommodated by existing designs, which can lead to issues like bending, breaking, and wear, as well as misalignment affecting shifting performance.
Innovation Solution
A chainring assembly that employs two separate chainrings held onto one spline using a single fastener, allowing for individual or joint replacement and maintaining radial alignment through stacking or nesting, thereby enhancing torque transfer and reducing central movement, while allowing either chainring to share torque and maintaining alignment without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a larger diameter chainring is used to go faster, then speed is improved, but vehicle clearance is reduced
Solution Approach 1:
The chainring system is segmented into two separate chainrings (first chainring and second chainring) that can be independently selected and installed. This segmentation allows the user to choose between different diameter chainrings based on whether they prioritize speed (larger diameter) or clearance (smaller diameter), resolving the contradiction by making the size selection adaptable rather than fixed in a single design
2Ease of manufacture
If traditional chainring designs are used, then manufacturing is simpler, but reliability is reduced due to bending, breaking, and wear
Solution Approach 1:
The chainring design incorporates dynamic torque distribution through splines that allow either chainring to share torque loads. The splined interface enables the chainrings to dynamically adjust torque distribution based on loading conditions, improving reliability by preventing overload on single chainrings while maintaining manufacturing simplicity through the use of standard splined connections
3Adaptability or versatility
If chainrings are replaced individually, then adaptability is improved, but alignment issues affect shifting performance
Solution Approach 1:
The two chainrings are nested on the same spline interface, with the first chainring having a larger diameter and the second chainring having a smaller diameter. This nesting arrangement ensures that both chainrings share the same center axis and radial alignment through the common spline connection, eliminating alignment issues when chainrings are individually replaced while maintaining full adaptability for different gearing configurations
4Strength
If multiple fasteners are used to secure chainrings, then strength is improved, but device complexity increases
Solution Approach 1:
The attachment mechanism merges the functions of multiple fasteners into a single fastener that secures both the first chainring and second chainring to the spline interface. This merging maintains attachment strength by using a unified fastening system while reducing device complexity by eliminating the need for multiple separate fasteners, thereby simplifying assembly and maintenance
Data Source
AI summary
A cinch direct mount 2× ring system is disclosed. One embodiment discloses a chainring assembly having a drive side crank arm with a chainring assembly interface including a plurality of splines, a circumference, and an axial length. The chainring assembly includes a first chainring having a first outer diameter and a first center assembly shape. The chainring assembly includes a second chainring having a second outer diameter and a second center assembly shape, the second outer diameter being different than the first outer diameter. The chainring assembly also includes a fastener to couple the first chainring and the second chainring with the chainring assembly interface, such that at least one of the first center assembly shape or the second center assembly shape engages with the plurality of splines.