Hydraulic Suspension System with Elastic Element for Vibration Control

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Solution Overview

Problem

Existing hydraulic suspension systems for vehicles fail to effectively limit vibrations transmitted from the wheel to the body during wheel deflections, compromising vehicle comfort.

Innovation Solution

A hydraulic suspension system incorporating a hydraulic attack stop with an elastically deformable element, such as a helical spring, interposed between the wheel set and the body, which forms an oscillating assembly around an equilibrium position, limiting vibration transmission through a combination of hydraulic and mechanical damping mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If an offset mechanical attack stop is used in the shock absorber, then the piston stroke is maintained and wheel travel is sufficient, but the vibrations transmitted from the wheel to the body during wheel deflections are not limited

Engineering Contradiction:
Improvepiston strokeVSAvoidvibration transmission
Core Design Contradiction:
Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

The invention divides the attack stop function into two separate components: a mechanical attack stop integrated in the shock absorber to maintain piston stroke, and a separate hydraulic attack stop offset from the shock absorber to limit vibration transmission. This segmentation allows each component to specialize in one function, resolving the contradiction between maintaining stroke and limiting vibrations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces an intermediary elastic element (such as a spring) between the hydraulic attack stop and the wheel set. This intermediary element creates an oscillating assembly that filters and dampens vibrations before they reach the body, while still allowing the hydraulic attack stop to effectively limit excessive wheel travel and protect the chassis.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a hydraulic attack stop is positioned close to the body to limit vibrations, then vibration transmission is reduced, but the piston stroke and wheel travel are reduced

Engineering Contradiction:
Improvevibration transmissionVSAvoidwheel travel
Core Design Contradiction:
Object-affected harmful factorsVSLength of moving object

Solution Approach 1:

The invention segments the attack stop system into two distinct parts positioned at different locations: the mechanical attack stop remains integrated in the shock absorber near the body to maintain piston stroke, while the hydraulic attack stop is positioned offset from the body to effectively limit vibrations without restricting wheel travel. This spatial segmentation resolves the contradiction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention positions the hydraulic attack stop at an offset location rather than directly along the shock absorber axis, creating a different spatial arrangement. This dimensional change allows the hydraulic attack stop to influence vibration transmission through a different geometric path while the mechanical attack stop maintains the necessary piston stroke along the original axis.

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

3Force

If an elastomer attack stop filled with liquid is used, then progressive damping of great amplitude is provided, but vibrations transmitted from the wheel to the body during wheel deflections are not limited

Engineering Contradiction:
Improvedamping forceVSAvoidvibration transmission
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The invention merges two different damping mechanisms into a single system: the elastomer material provides progressive damping of great amplitude, while the hydraulic fluid within the same attack stop provides additional vibration limiting capability. This combination of material properties within one component achieves both high damping force and effective vibration limitation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The attack stop uses a composite structure combining elastomer material with internal hydraulic fluid filling. The elastomer provides non-linear progressive damping characteristics, while the hydraulic fluid adds viscous damping effects that specifically target vibration frequencies, creating a composite damping system that addresses both requirements simultaneously.

Inventive Principle:
Principle #40Composite materials

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 system significantly reduces the transmission of vibrations to the vehicle body, enhancing occupant comfort by absorbing mechanical vibrations and providing progressive damping during wheel deflections.

Implementation Method 1

the cylinder of the hydraulic attack stop comprises an internal cylindrical wall defining an internal compression chamber filled with a hydraulic fluid and in which the piston is movable relative to the cylinder, and an external concentric compensation chamber the volume occupied by the rod in the compression chamber

Methodology Applied
Scientific EffectHydraulic damping: Viscous Damping

Implementation Method 2

the suspension system comprises an elastically deformable element interposed between the wheel set of the vehicle and the hydraulic attack stop

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

the internal cylindrical wall of the cylinder of the hydraulic attack stop comprises a plurality of radial holes passing through it and allowing, when the piston and the cylinder of the hydraulic attack stop move relative to each other, the circulation of the fluid between the compression chamber and the compensation chamber

Methodology Applied
Scientific EffectFluid flow through restricted passages: Viscous Damping

Data Source

PatentEP3251879B1Hydraulic suspension system of a vehicle wheel
Publication Date: 2019.03.20 PSA AUTOMOBILES SA
  • EP3251879B1 patent drawingFigure 1
  • EP3251879B1 patent drawingFigure 2A~2B
  • EP3251879B1 patent drawingFigure 2C~2D

AI summary

The invention relates to a hydraulic suspension system for a vehicle, particularly an automobile. The hydraulic suspension system according to the invention comprises a hydraulic bump stop (2) and an elastically deformable element (4) interposed between the vehicle's wheel assembly and the hydraulic bump stop (2). The element is integral with the vehicle's wheel assembly and the hydraulic bump stop (2) so as to form an assembly oscillating around an equilibrium position. In this equilibrium position, the hydraulic bump stop (2) is positioned at a distance from the vehicle body (3) and the wheel assembly, and is arranged to limit the transmission of wheel vibrations to the vehicle body (3) during wheel travel. The invention finds application in the automotive industry.