Hydraulic Shock Absorber Fluid Leakage via Colloidal Suspension

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Solution Overview

Problem

Hydraulic shock absorbers face leakage issues due to the trade-off between effective fluid barrier performance and seal lifespan, particularly when static for prolonged periods, despite advancements in seal technology and materials.

Innovation Solution

Incorporating a colloidal suspension of 1-25% inorganic particles by weight in the shock absorber fluid, which exhibits non-Newtonian characteristics, such as thixotropy, to enhance viscosity and resist leakage without affecting dynamic properties, and using these particles like silicates or aluminosilicates in a liquid medium like oil.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a strong biasing force is applied to the dynamic seal to improve fluid barrier effectiveness, then leakage resistance is improved, but seal wear increases and lifespan decreases

Engineering Contradiction:
Improvefluid barrier effectivenessVSAvoidseal lifespan
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the physical-chemical parameters of the shock absorber fluid by adding inorganic particles to create a colloidal suspension. This modifies the fluid's viscosity characteristics, allowing it to become more viscous at rest (improving seal lubrication and reducing wear) while maintaining lower viscosity during dynamic operation (preserving performance). This parameter change resolves the contradiction by reducing the biasing force needed on the seal.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite fluid system by combining base shock absorber fluid with inorganic particles (such as silica, glass beads, or metal oxides) to form a colloidal suspension. This composite material provides both the lubrication properties needed to reduce seal wear and the viscosity characteristics to maintain fluid barrier effectiveness, resolving the trade-off between seal lifespan and leakage resistance.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If conventional seal technology and materials are used to improve fluid confinement, then manufacturing capability is maintained, but leakage occurs particularly during prolonged static periods

Engineering Contradiction:
Improveseal installation capabilityVSAvoidleakage resistance during static periods
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent modifies the rheological parameters of the shock absorber fluid by incorporating inorganic particles that create thixotropic or shear-thinning behavior. The fluid becomes more viscous when static, improving seal lubrication and preventing leakage during prolonged stationary periods, while maintaining appropriate viscosity during dynamic operation. This resolves the contradiction without changing seal design or manufacturing processes.

Inventive Principle:
Principle #35Parameter changes

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 colloidal suspension significantly reduces fluid leakage, especially when the shock absorber is stationary, while maintaining normal operational dynamics during movement, and provides improved corrosion resistance.

Implementation Method 1

The inorganic particles impart non-Newtonian characteristics to the shock absorbing fluid which cause it to be more viscous when at rest than when under shear stress

Methodology Applied
Scientific EffectThixotropy: Thixotropy

Implementation Method 2

The inorganic particles impart non-Newtonian characteristics to the shock absorbing fluid which cause it to be more viscous when at rest than when under shear stress

Methodology Applied
Scientific EffectNon-Newtonian fluid behavior: Non-Newtonian Fluids

Data Source

PatentEP3091248B1Hydraulic shock absorber
Publication Date: 2019.07.03 MESSIER DOWTY
  • EP3091248B1 patent drawingFigure 1

AI summary

A hydraulic shock absorber (10) comprising an inner housing portion (12) slidably coupled to an outer housing portion (14) to define a variable size chamber for containing shock absorber fluid and a dynamic seal (24) having a sealing face adjacent to the inner housing portion for confining shock absorber fluid to the chamber. The shock absorber fluid comprises a colloidal suspension of inorganic particles in liquid, the colloidal suspension comprising 1 - 25 % by weight inorganic particles.