Electronic Decoupling Hub Assembly for Suspension Chain Growth

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Solution Overview

Problem

Rear suspension systems on bicycles cause chain tightness issues due to articulation, leading to detrimental suspension performance and rider feedback, as the distance between the center chain sprocket and rear wheel sprocket changes, affecting chain stay length and chain growth.

Innovation Solution

An electronic automatically decoupling hub assembly with a controller, inductors, and pawls that selectively engage or disengage with a ratchet ring, allowing the hub to transition between force transfer and freewheel states based on sensor inputs, such as from accelerometers or optical detection devices, to manage chain growth and reduce pedal feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If rear suspension articulation is allowed to improve terrain traversal capability, then suspension performance is improved, but chain tightness changes causing detrimental feedback to rider

Engineering Contradiction:
Improvesuspension performanceVSAvoidchain growth feedback
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the harmful chain growth effect by allowing the rear derailleur to disengage from the cage assembly when chain length changes occur due to suspension articulation. This removes the source of detrimental feedback while preserving suspension functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a clutch mechanism as an intermediary between the rear derailleur and cage assembly. This mediator allows selective engagement and disengagement based on chain growth conditions, enabling the system to filter out harmful effects while maintaining useful suspension articulation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the rear derailleur remains engaged to maintain chain tension, then chain tightness is maintained, but suspension articulation causes detrimental performance impact

Engineering Contradiction:
Improvechain tensionVSAvoidsuspension performance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent implements a dynamic engagement system where the rear derailleur can transition between engaged and disengaged states. The clutch mechanism responds to chain growth conditions, dynamically adjusting the connection between derailleur and cage assembly to optimize both chain tension and suspension performance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent removes the harmful interaction between chain growth and suspension articulation by allowing temporary disengagement of the rear derailleur from the cage assembly. This extraction of the problematic connection enables independent optimization of chain tension maintenance and suspension performance.

Inventive Principle:
Principle #2Taking out (Extraction)

3Object-affected harmful factors

If an electronic automatically decoupling hub assembly is implemented to manage chain growth, then pedal feedback is reduced, but device complexity increases

Engineering Contradiction:
Improvepedal feedbackVSAvoidhub assembly complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical chain tensioning mechanisms with an electronic automatically decoupling hub assembly. This electronic system uses sensors and controllers to detect chain growth conditions and automatically adjust hub engagement, eliminating the need for complex mechanical tensioning components while reducing pedal feedback.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The electronic hub assembly incorporates self-service capabilities through integrated sensors that automatically detect chain growth conditions and trigger appropriate engagement or disengagement actions. The system monitors its own operational state and autonomously adjusts to maintain optimal performance without external intervention.

Inventive Principle:
Principle #25Self-service

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 mitigates the impact of suspension-induced chain growth on rear wheel traction and pedal feedback, maintaining optimal chain tension and reducing harsh ride conditions by automatically adjusting the hub's engagement state in response to terrain changes.

Implementation Method 1

an inductor comprising at least one pawl to selectively engage or disengage with the at least one tooth of the ratchet ring

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The sensor may be an accelerometer, an optical detection device, or an image capturing device

Methodology Applied
Scientific EffectAcceleration detection: Accelerometer

Implementation Method 3

The sensor may be an accelerometer, an optical detection device, or an image capturing device

Methodology Applied
Scientific EffectOptical detection: Photoelectric Effect

Data Source

PatentEP4350162A1Suspension enhancing hub and rear derailleur assembly
Publication Date: 2024.04.10 FOX FACTORY INC
  • EP4350162A1 patent drawingFigure 1
  • EP4350162A1 patent drawingFigure 2
  • EP4350162A1 patent drawingFigure 3A~3B

AI summary

An electronic automatically decoupling hub assembly (1000) is disclosed herein. The assembly has an axle (15) and a hub shell (1005) rotationally positioned about the axle. A controller (1010) provides automatic activation/deactivation signals to an inductor (1015). The assembly has a bearing (1025) rotationally positioned about the axle and a rachet ring (1020), having a plurality of teeth, rotationally positioned about the bearing. One or more pawls (1030) are provided to engage with at least some of the teeth of the ratchet ring and a seal (1035) is used to contain the pawls within the assembly. A cassette body assembly (1040) is coupled with the rachet ring and an end cap (1045) is used to prevent a contaminant from entering into the decoupling hub assembly.