Shock Assembly With Auto Ride Height Adjustment Under Load

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Solution Overview

Problem

Vehicle suspension systems face challenges in maintaining optimal ride height when additional weight is added, leading to changes in vehicle geometry, steering issues, and increased stiffness, as existing shock assemblies do not effectively adjust to accommodate varying loads without compromising performance or requiring component changes.

Innovation Solution

A shock assembly with an internal floating piston (IFP) pump assembly and a spring preload piston assembly that automatically adjusts ride height by pumping working fluid into or releasing it from a fluid chamber, using a check tunable orifice and bleed control valve to manage fluid flow and maintain optimal ride height during operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the shock is set to a softer setting for a lighter rider, then ride comfort is improved, but the available travel becomes insufficient when a heavier rider uses the same shock

Engineering Contradiction:
Improveride comfortVSAvoidavailable travel
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the spring preload force through an adjustable preload mechanism. This allows the suspension system to change its stiffness characteristic based on rider weight, maintaining optimal ride comfort and available travel across different loading conditions without requiring physical component changes

Inventive Principle:
Principle #35Parameter changes

2Length of moving object

If the shock is set to a harder setting for a heavier rider, then available travel is maintained, but ride comfort deteriorates when a lighter rider uses the same shock

Engineering Contradiction:
Improveavailable travelVSAvoidride comfort
Core Design Contradiction:
Length of moving objectVSEase of operation

Solution Approach 1:

The adjustable preload mechanism enables parameter changes in spring stiffness by allowing users to modify the preload force. This resolves the contradiction by enabling the same shock to provide both hard and soft settings, maintaining available travel for heavier riders while preserving ride comfort for lighter riders through parameter adjustment rather than component replacement

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If shock components are changed to accommodate different rider weights, then performance characteristics are optimized, but device complexity and ease of repair increase

Engineering Contradiction:
Improveperformance characteristicsVSAvoidcomponent configuration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements universality by designing a single shock assembly that can serve multiple rider weight categories through the adjustable preload mechanism. This eliminates the need for multiple different shock components, reducing device complexity and ease of repair concerns while maintaining adaptability across different riding conditions

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The adjustable preload mechanism introduces dynamics to an otherwise static suspension system. Users can dynamically adjust the preload setting to match different rider weights, allowing the same physical components to adapt to varying performance requirements without increasing complexity

Inventive Principle:
Principle #15Dynamics

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 allows for real-time adjustment of ride height to maintain the vehicle's original geometric configuration, reducing the impact of added weight on suspension performance, steering, and ride quality, while minimizing changes to damping settings and preload.

Implementation Method 1

an internal floating piston (IFP) pump assembly; a pump fixedly located within said IFP fluid chamber

Methodology Applied
Scientific EffectHydraulic pump: Pump

Implementation Method 2

a check tunable orifice to provide said working fluid to said pump

Methodology Applied
Scientific EffectOrifice flow control: Flow Separation

Implementation Method 3

a bleed control valve to allow said working fluid to be released from said spring preload piston assembly

Methodology Applied
Scientific EffectPressure relief valve: Valve

Implementation Method 4

an IFP to separate said working fluid from a compressible fluid in an IFP fluid chamber

Methodology Applied
Scientific EffectFloating piston separation: Physical Containment

Implementation Method 5

a spring preload piston assembly; a fluid chamber in fluid communication with a fluid pathway of said IFP pump assembly

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Data Source

PatentEP3875800B1A shock assembly
Publication Date: 2025.01.15 FOX FACTORY INC
  • EP3875800B1 patent drawingFigure 1
  • EP3875800B1 patent drawingFigure 2A
  • EP3875800B1 patent drawingFigure 2B

AI summary

A shock assembly (100) comprising: a main chamber (220) comprising a working fluid therein; a damping piston (210) coupled to a piston shaft (130), said damping piston disposed in said main chamber to divide said main chamber into a compression side fluid chamber and a rebound side fluid chamber; and an automatic ride height adjustment assembly comprising: an internal floating piston (IFP) pump assembly (310); and a spring preload piston assembly (266).