Spring Preload Cylinder Layout for Ride Height and Cavitation Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Vehicle suspension systems face challenges in maintaining optimal ride height and damping characteristics, particularly under varying loads, as existing shock assemblies can experience cavitation and malfunction during rapid compression, leading to reduced damping efficiency and noise.

Innovation Solution

A spring preload system that includes a cylinder, piston shaft, main damping piston, preload cylinder, and valves to control fluid flow, allowing for adjustment of preload and damping characteristics without external pumps, using a compression stroke to pump fluid into the preload cylinder and alter the spring's preload and damping properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing shock assemblies are used, then the basic damping function is provided, but cavitation occurs during rapid compression leading to malfunction and reduced damping efficiency

Engineering Contradiction:
Improvedamping efficiencyVSAvoidcavitation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system applies preliminary anti-action by pre-charging the preload cylinder with fluid pressure before compression events occur. This pre-established pressure counteracts the negative pressure that would otherwise cause cavitation during rapid compression strokes, preventing the harmful effect before it can manifest.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The preload cylinder acts as an intermediary element between the compression chamber and the spring. By introducing this intermediate fluid-filled chamber with controlled pressure, the system mediates the compression forces to prevent direct cavitation in the main damping circuit while maintaining damping functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If ride height and damping characteristics are to be adjusted under varying loads, then system adaptability improves, but system complexity increases due to additional components

Engineering Contradiction:
Improveride height adjustmentVSAvoidsystem components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The preload cylinder serves multiple functions simultaneously: it adjusts ride height by controlling spring preload, prevents cavitation through pressure maintenance, and enables load adaptation. This multi-functionality achieves adaptability without proportionally increasing system complexity, as one component performs several critical roles.

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

Solution Approach 2:

The system achieves self-adjustment through the natural compression strokes of the shock assembly itself, which pump fluid into the preload cylinder without requiring external pumps or complex control systems. The system serves itself by utilizing its own operational cycles to maintain the necessary fluid pressure.

Inventive Principle:
Principle #25Self-service

3Reliability

If fluid flow is restricted to prevent cavitation, then damping efficiency improves, but fluid flow control complexity increases

Engineering Contradiction:
Improvecavitation preventionVSAvoidvalve control
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system extracts the pressure control function from the main damping circuit by separating it into the dedicated preload cylinder. This extraction allows cavitation prevention to be handled independently through simple fluid transfer to the preload cylinder, rather than requiring complex flow control valves in the primary damping path.

Inventive Principle:
Principle #2Taking out (Extraction)

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

This system effectively adjusts ride height and damping characteristics in response to load changes, preventing cavitation and enhancing the shock assembly's performance by allowing for increased preload and compression damping, thereby improving ride comfort and stability.

Implementation Method 1

a compression stroke is used to pump fluid into said preload cylinder in order to increase the preload

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

The spring may be braced against said preload flange

Methodology Applied
Scientific EffectElastic potential energy: Spring

Implementation Method 3

The valve may be adapted to restrict flow of fluid to said preload cylinder

Methodology Applied
Scientific EffectFluid flow restriction: Valve

Data Source

PatentEP4272983A1Spring preload system
Publication Date: 2023.11.08 FOX FACTORY INC
  • EP4272983A1 patent drawingFigure 1
  • EP4272983A1 patent drawingFigure 2
  • EP4272983A1 patent drawingFigure 3

AI summary

A spring preload system (200) comprising: a cylinder (120), said cylinder comprising an outer diameter; a body to house at least said cylinder; a piston shaft (130); a main damping piston (202), said main damping piston coupled to said piston shaft (130) and configured for operation within said cylinder (120), said main damping piston (202) configured to divide said cylinder into a compression side and a rebound side; a preload cylinder(206); and a valve (210), wherein said valve (210) is fluidly disposed between said compression side and said preload cylinder (206).