Vehicle Shock Absorber Dual Reservoir Fluid Equalization

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Solution Overview

Problem

Existing multiple reservoir suspension systems face issues with fluid retention and require complex controls, leading to potential fluid loss and 'crashing' due to unequal metering in rebound directions.

Innovation Solution

A shock absorber design featuring a main damper cylinder with two reservoirs connected through fluid paths that allow for selective communication, enabling equalization of pressure and fluid flow in series during extension and compression, with user-adjustable valves for operational modes that ensure all fluid is utilized, preventing fluid loss and providing adjustable spring rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate reservoir chambers are used with distinct paths and metering devices, then the shock absorber can provide adjustable damping characteristics, but fluid loss and crashing occur due to unequal metering in rebound directions

Engineering Contradiction:
Improveadjustable damping characteristicsVSAvoidfluid retention
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent merges the reservoir chambers into a single integrated reservoir that serves both compression and rebound functions. This single reservoir design eliminates the fluid loss problem caused by unequal metering in separate chambers, while still providing adjustable damping characteristics through a single adjustable metering device that controls fluid flow in both directions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single reservoir is designed to perform multiple functions: it serves as both a compression reservoir and a rebound reservoir, and also functions as an air spring chamber. This multi-functional design replaces the need for separate specialized chambers while maintaining the adjustable damping capability through universal metering mechanisms.

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

2Productivity

If multiple separate reservoirs are implemented, then the shock absorber can utilize both reservoirs for extended travel, but complex controls are required to manage fluid flow between reservoirs

Engineering Contradiction:
Improveextended travel capabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines multiple reservoir functions into a single reservoir chamber that provides extended travel capability without requiring complex control systems. The single reservoir design with integrated metering eliminates the need for multiple valves and control mechanisms required to manage fluid flow between separate reservoirs.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If separate metering devices are used for each reservoir path, then adjustable damping is achieved, but fluid loss occurs due to unequal metering in rebound directions

Engineering Contradiction:
Improveadjustable dampingVSAvoidfluid loss
Core Design Contradiction:
Adaptability or versatilityVSLoss of substance

Solution Approach 1:

The patent merges multiple metering devices into a single adjustable metering mechanism that controls fluid flow for both compression and rebound operations. This unified metering system ensures equal and consistent fluid metering in both directions, preventing the fluid loss that occurs when separate metering devices create unequal flow rates.

Inventive Principle:
Principle #5Merging (Combining)

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 design ensures all fluid is retained and utilized effectively, preventing 'crashing' and allowing for adjustable spring rates, enhancing the shock absorber's performance and user control.

Implementation Method 1

Some shock absorbers utilize gas as a spring medium in place of, or in addition to, mechanical springs

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The damper consists of a piston and shaft telescopically mounted in a fluid filled cylinder. The purpose of the damper is to control the speed at which the shock absorber operates

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Data Source

PatentEP2258961B1Vehicle shock absorber
Publication Date: 2021.05.12 FOX FACTORY INC
  • EP2258961B1 patent drawingFigure 1
  • EP2258961B1 patent drawingFigure 2
  • EP2258961B1 patent drawingFigure 3

AI summary

A shock absorber (100) comprising: a main damper cylinder (125) having a variable volume portion (188) with a fluid therein; a first reservoir (300) and a second reservoir (400) and a fluid flow path (150, 151)) between the variable volume portion (188) and at least one of the first (300) and second reservoirs (400); and a second fluid flow path (160) between the first and second reservoirs.