Damper Piston Fluid Ramp for Shock Absorber Noise and Heat Control

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Solution Overview

Problem

Conventional shock absorbers experience temperature instability and noise issues due to direct fluid impact on the interior walls of the pressure/damper tube, leading to reduced damping performance and increased noise levels.

Innovation Solution

A fluid redirection system with a fluid ramp on the damper piston redirects fluid flow to merge seamlessly with the boundary layer along the cylinder wall, reducing turbulence and normal impact, thereby enhancing heat exchange and minimizing noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If fluid flows directly from the damper piston ports to the cylinder wall, then the structure is simple, but temperature stability deteriorates and noise increases

Engineering Contradiction:
Improvetemperature stabilityVSAvoidpiston structure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The piston surface is segmented into different functional zones: a first surface area with a first inclination angle for compression stroke fluid redirection, and a second surface area with a second inclination angle for rebound stroke fluid redirection. This segmentation allows optimized fluid flow control for each stroke direction, improving temperature stability through enhanced boundary layer interaction without requiring completely separate structures for each function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention adds a dimensional element by introducing inclined surface areas on the piston instead of using flat or simple curved surfaces. The inclination angles create a three-dimensional flow path that redirects fluid along the cylinder wall, increasing the interaction path length and improving heat exchange efficiency. This dimensional change transforms the fluid flow from a direct radial path to an angled path that engages with the boundary layer.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Object-generated harmful factors

If fluid flows directly impacting the cylinder wall, then the device structure is simple, but noise levels increase by up to 70-80%

Engineering Contradiction:
Improvenoise levelVSAvoidpiston structure complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The inclined surface areas act as intermediaries between the fluid exiting the piston ports and the cylinder wall. Instead of allowing direct impact, the inclined surfaces redirect the fluid flow at angles that cause it to merge with the boundary layer along the cylinder wall. This intermediary action reduces the formation of strong shock waves and turbulent eddies that generate noise, while still achieving effective fluid redistribution.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If fluid flow directly impacts the cylinder wall, then no additional components are needed, but damping performance decreases due to turbulence

Engineering Contradiction:
Improvedamping performanceVSAvoidpiston structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The piston is designed with local quality variations through different inclination angles on different surface areas. The first inclination angle is optimized for compression stroke fluid redirection to minimize turbulence and maximize boundary layer interaction, while the second inclination angle is optimized for rebound stroke. This localized optimization of surface geometry at different positions on the piston enables improved damping performance for both stroke directions without requiring a completely different piston design.

Inventive Principle:
Principle #3Local quality

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 fluid redirection system improves temperature stability, reduces noise by up to 70-80%, and maintains or enhances damping performance by preventing direct fluid impact and cavitation, resulting in a smoother operation and better heat exchange.

Implementation Method 1

redirects fluid flow to merge seamlessly with the boundary layer along a wall of a cylinder

Methodology Applied
Scientific EffectBoundary layer: Boundary Layer

Implementation Method 2

enhancing heat exchange and minimizing noise

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP4477916A1Fluid redirection system
Publication Date: 2024.12.18 FOX FACTORY INC
  • EP4477916A1 patent drawingFigure 1
  • EP4477916A1 patent drawingFigure 2~3
  • EP4477916A1 patent drawingFigure 4~5

AI summary

A fluid redirection system comprising: a damper piston (200), the damper piston having a plurality of compression ports (202) and a plurality of rebound ports (204); and a fluid ramp (516) on a first side of the damper piston (200), the fluid ramp (616) being of a shape that creates an angled exit for fluid exiting the damper piston (200).