Vehicle Suspension Strut With Compression-Only Damping Valve

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Solution Overview

Problem

Existing suspension struts for vehicles face challenges in achieving faster reaction times during extension, as they often retain damping forces that hinder quick movement, and existing designs do not effectively manage damping forces differently between compression and extension phases.

Innovation Solution

A suspension strut design featuring a damper assembly with a side wall damper aperture and a valve mechanism that remains closed during extension, allowing fluid flow only during compression, combined with a floating piston and multiple chambers to manage pressure and volume effectively, reducing damping forces during extension and enhancing load-carrying capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a damper assembly provides damping force during both compression and extension, then the suspension strut maintains stability, but the extension reaction time becomes slower

Engineering Contradiction:
Improveextension reaction timeVSAvoidsuspension stability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The damper valve dynamically changes its state based on the operational phase: closed during compression to provide damping, and open during extension to reduce damping resistance. This dynamic adjustment allows the system to optimize performance for each phase independently, achieving fast extension response while maintaining compression stability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The damping function is segmented into two distinct operational modes: compression damping (valve closed) and extension damping (valve open). By separating the damping behavior for compression and extension phases, the system can provide strong damping when needed (compression) while minimizing damping resistance during extension for faster response.

Inventive Principle:
Principle #1Segmentation

2Force

If the damper valve aperture is small, then damping force during compression is effective, but the valve requires larger differential pressure to open during extension

Engineering Contradiction:
Improvedamping force during compressionVSAvoiddifferential pressure required to open valve
Core Design Contradiction:
ForceVSStress or pressure

Solution Approach 1:

The valve aperture is positioned on the side wall of the damper assembly rather than on the end face. This spatial repositioning allows the full axial area of the damper assembly to be utilized for generating damping force during compression, while the side-wall location provides adequate perimeter area for the aperture to open with minimal differential pressure during extension.

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

Solution Approach 2:

Different regions of the damper assembly are assigned different functions: the axial face area is dedicated to maximizing damping force generation, while the side wall area is utilized for the valve aperture to minimize opening pressure. This local differentiation optimizes both compression damping effectiveness and extension response characteristics.

Inventive Principle:
Principle #3Local quality

3Productivity

If the first chamber volume is small, then the strut responds quickly to compression, but the piston is prone to bottoming out

Engineering Contradiction:
Improvecompression response speedVSAvoidpiston bottoming out risk
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The first cavity is pre-configured within the piston structure to provide additional volume to the first chamber. This preliminary volume expansion prevents the piston from bottoming out during compression while maintaining sufficiently small overall chamber volume to preserve quick compression response characteristics.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The first cavity is nested within the piston body, creating an internal volume that contributes to the first chamber's total volume. This nested configuration increases the effective volume without significantly increasing the external dimensions, thereby preventing piston bottoming out while maintaining compact size and fast response.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 enables faster extension reactions by minimizing damping forces during extension while maintaining effective damping during compression, reducing the risk of piston bottoming out and allowing for increased load capacity without increased maximum operating pressure.

Implementation Method 1

a bias device, wherein the bias device biases the plate towards the valve aperture and axial face to close the valve aperture

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

fluid flowing through the damper assembly during relative compression between the first point and the second point causes the plate to move away from the valve aperture and axial face to open the damper valve

Methodology Applied
Scientific EffectFluid pressure: Pressure Increase

Implementation Method 3

a damper assembly adapted to provide a damping force as fluid flows through the damper assembly during relative compression between the first point and the second point

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Data Source

PatentEP3710720B1Suspension strut
Publication Date: 2023.11.01 BAE SYSTEMS PLC
  • EP3710720B1 patent drawingFigure 1
  • EP3710720B1 patent drawingFigure 2~3
  • EP3710720B1 patent drawingFigure 4~5

AI summary

A suspension strut (10) for a vehicle comprises :a first connector (12) for connecting to a first point on the vehicle; a second connector (14) for connecting to a second point on the vehicle; and a damper assembly (30) adapted to provide a damping force as fluid flows through the damper assembly (30) during relative compression between the first point and the second point, wherein the damper assembly (30) comprises a side wall (310) and a damper aperture (312) in the side wall (310), wherein the damper aperture (312) is open throughout operation of the strut (10) to allow fluid to flow through the damper assembly (30).