Pneumatic Suspension with Side Chamber for Stiffness Control

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Solution Overview

Problem

Existing suspension systems with helical springs and hydraulic dampers experience variations in stiffness due to gas transfer between chambers, affecting driving comfort and safety, particularly in vehicles like motorcycles and bicycles.

Innovation Solution

A pneumatic suspension system with a cylindrical cavity divided by a piston into two chambers, featuring a side chamber for controlled gas transfer between the chambers to balance pressures without sudden stiffness changes, using a single valve for filling and adjusting pressures in three pressurized chambers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gas transfer means are provided between upper and lower chambers to balance pressures, then pressure equilibrium is achieved, but sudden stiffness variation occurs during operation

Engineering Contradiction:
Improvepressure equilibriumVSAvoidsuspension stiffness
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The gas transfer path is segmented into two separate sequential paths: upper chamber → side chamber → lower chamber, and lower chamber → side chamber → upper chamber. The piston divides the main chamber into upper and lower sections, and the side chamber acts as an intermediate buffer zone. This segmentation prevents direct gas transfer between chambers, eliminating sudden stiffness changes while maintaining pressure equilibrium capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The side chamber serves as an intermediary element between the upper and lower chambers. Gas must pass through this intermediate chamber to transfer between the main chambers, which smooths out pressure equalization and prevents abrupt stiffness variations. The side chamber mediates the gas transfer process to maintain suspension stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If multiple valves are provided for adjusting pressures in different chambers, then precise pressure control is achieved, but device complexity increases

Engineering Contradiction:
Improvepressure control precisionVSAvoidnumber of valves
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

A single adjustment valve is designed to control pressure in multiple chambers sequentially. The valve can adjust pressure in the upper chamber, lower chamber, and side chamber through different operational positions or sequences. This multi-functional valve design reduces the total number of valves from three (one per chamber) to one, simplifying the device while maintaining precise pressure control capability.

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

Solution Approach 2:

The pressure adjustment functions for multiple chambers are merged into a single valve mechanism. Instead of having separate valves for the upper chamber, lower chamber, and side chamber, one integrated valve performs all pressure adjustment tasks by controlling gas flow to different chambers in sequence or simultaneously, reducing complexity while preserving control precision.

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 system maintains consistent stiffness and comfort by gradually equalizing pressures between chambers, allowing for easy adjustment of suspension attitude and stiffness with fewer operating settings, reducing the risk of accidents and improving user experience.

Implementation Method 1

a pneumatic system replacing the coil spring... a cylindrical cavity in which is slidably mounted a piston dividing the cylindrical cavity into two working chambers: a lower chamber and an upper chamber each receiving a gas

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 2

a spring inserted in the lower chamber, adapted to push the piston back towards the upper chamber

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

the means for transferring gas consist in a side chamber formed in the internal wall of the cylindrical body, said side chamber being adapted to come successively opposite the lower chamber and the upper chamber according to the position of the piston

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 4

gradually balancing the pressures between the two chambers, transporting fluid from the more pressurized chamber to the less pressurized chamber

Methodology Applied
Scientific EffectPressure equalization: Pressure Gradient

Implementation Method 5

a sealing ring... The chamber has a longitudinal dimension greater than the thickness of a seal placed between an external face of the piston and the internal surface of the cylindrical cavity

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3085988B1Pneumatic suspension device
Publication Date: 2018.09.12 BOSSARD OLIVIER
  • EP3085988B1 patent drawingFigure 1
  • EP3085988B1 patent drawingFigure 2a~2d
  • EP3085988B1 patent drawingFigure 3a~3d

AI summary

The invention relates to a suspension system comprising a body (15) having a cylindrical cavity (2) in which a piston (1) is mounted to slide, dividing the cylindrical cavity into two working chambers (10, 11): a lower chamber (10) and an upper chamber (11) each receiving a gas, the piston (1) being connected to a piston rod (7) exiting the cylindrical cavity (2) through a sealing ring (5).The suspension system includes an outer tube (16), the body (15) sliding within this outer tube (16), said outer tube (16) being engaged around the piston rod (7) and having at its free end a lower plug (17) to which the end of the piston rod (7) is attached, the space between the lower plug (17) of the outer tube (16) and the sealing ring (5) defining within the outer tube (16) a third chamber (18) filled with gas by a pre-charge valve (19), The suspension device includes a single valve (4) for filling the lower and upper chambers, and means for transferring gas from one of the two working chambers (10, 11) to the other, according to predetermined conditions.