Decoupling Rear Derailleur Assembly for Suspension Chain Growth
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Solution Overview
Problem
Rear suspension systems on bicycles can cause chain growth due to articulation, leading to detrimental effects on suspension performance and rider feedback, as well as potential chain disengagement from sprockets.
Innovation Solution
A disengageable derailleur assembly with a P-Knuckle assembly and a cage assembly that can selectively and frictionally engage or disengage, allowing the P-Knuckle assembly to retain orientation information with the cage assembly during disengagement, thus maintaining suspension position and chain drift needs while allowing free movement of the cage assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If rear suspension articulation is allowed to improve terrain traversal capability, then suspension performance is improved, but chain growth occurs causing detrimental feedback to the rider
Solution Approach 1:
The derailleur assembly is segmented into two independently rotatable components: a body portion that rotates with the sprocket to maintain chain tension, and a cage assembly that rotates freely to accommodate chain length changes without transmitting forces to the suspension. This segmentation allows each component to perform its specific function independently.
Solution Approach 2:
The harmful chain growth feedback is extracted from the suspension system by allowing the cage assembly to rotate independently. This separates the chain tension maintenance function (performed by the body portion) from the chain length accommodation function (performed by the cage assembly), removing the detrimental feedback path.
2Adaptability or versatility
If rear suspension articulation is allowed to improve terrain traversal capability, then suspension performance is improved, but chain disengagement from sprockets may occur
Solution Approach 1:
The derailleur assembly is segmented into two independently rotatable components: a body portion that rotates with the sprocket to maintain chain tension, and a cage assembly that rotates freely to accommodate chain length changes. This segmentation prevents chain disengagement by ensuring the body portion maintains proper chain tension while the cage absorbs length variations.
Solution Approach 2:
The body portion is designed to rotate in unison with the sprocket before chain disengagement can occur, preliminarily maintaining proper chain tension and alignment. This preliminary action prevents the chain from becoming loose or disengaging during suspension articulation.
3Reliability
If the cage assembly is fixed to maintain chain tension, then chain engagement reliability is improved, but suspension performance deteriorates due to cage forces
Solution Approach 1:
The derailleur assembly is segmented into two independently rotatable components. The body portion maintains chain tension by rotating with the sprocket, while the cage assembly rotates independently to accommodate chain length changes without generating forces on the suspension. This segmentation eliminates the harmful cage forces while maintaining chain engagement reliability.
Solution Approach 2:
The cage assembly is designed with independent rotatable bearings that allow it to dynamically adjust its position as the chain length changes during suspension articulation. This dynamic capability allows the cage to follow chain movements without resisting them, eliminating harmful forces on the suspension while maintaining proper chain tension through the body portion.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces the adverse feedback to the rider by minimizing the impact of suspension-induced chain growth on the derailleur, while ensuring proper chain tension and propulsion of the bicycle.
Implementation Method 1
The cage assembly includes a lower idler pulley and an upper idle pulley, each having a rotatable bearing
Data Source
AI summary
An electronic automatically decoupling hub assembly. The decoupling hub assembly has an axle and a hub shell rotationally positioned about the axle. A controller provides automatic activation/deactivation signals to an inductor. The decoupling hub assembly has a bearing rotationally positioned about the axle and a cassette body assembly, having a plurality of teeth, rotationally positioned about the bearing. One or more pawls are provided to engage with at least some of the teeth of the cassette body assembly and a seal is used to contain the pawls within the decoupling hub assembly. A cassette body assembly is coupled with the ratchet ring and an end cap is used to prevent a contaminant from entering into the decoupling hub assembly.