Air Spring Strut Ventilation Openings Dirt Protection

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Solution Overview

Problem

Air spring bellows in passenger vehicles are sensitive to deposits and foreign objects, leading to abrasion and potential failure due to inadequate protection from dirt and contaminants during spring movements, and existing ventilation designs allow dirt and pollutants to enter the bellows, compromising their protective function.

Innovation Solution

The air spring strut incorporates additional ventilation openings with lower flow resistance, strategically placed to reduce air intake during rebound movements and prevent air escape during compression, along with non-return means and filter elements to control airflow and prevent contamination, enhancing the self-cleaning effect and maintaining the bellows' protective function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a bellows is added to protect the air spring bellows from dirt, then protection from contaminants is improved, but gas exchange between enclosed air and polluted air outside becomes necessary

Engineering Contradiction:
Improveprotection from dirtVSAvoidgas exchange
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The bellows is divided into multiple sealing sections that can independently expand and contract, allowing the protective function to be maintained while enabling controlled gas exchange through designated ventilation openings rather than compromising the entire sealing structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bellows acts as an intermediary protective layer between the air spring bellows and external contaminants, while ventilation openings provide a controlled intermediary pathway for gas exchange, preventing direct contact between pollutants and the internal system

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If ventilation openings are provided at the base of the bellows, then gas exchange is enabled, but dust and foreign bodies are sucked into the inside of the bellows during spring movements

Engineering Contradiction:
Improvegas exchangeVSAvoiddust entry
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Instead of placing ventilation openings at the base where dust enters during compression, the patent positions them at the top of the bellows, inverting the conventional approach. This allows air to be drawn from the cleaner upper region rather than sucking in contaminated air from the lower region during spring movement

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The ventilation openings are strategically positioned at specific locations (top of bellows) rather than uniformly distributed, creating local quality differences in airflow patterns to prevent dust entry while maintaining gas exchange functionality

Inventive Principle:
Principle #3Local quality

3Ease of operation

If thin-walled air spring bellows are used to ensure high rolling comfort, then comfort is improved, but sensitivity to deposits and foreign objects increases leading to abrasion and failure

Engineering Contradiction:
Improverolling comfortVSAvoidsensitivity to deposits
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The bellows provides beforehand protection by creating a sealed barrier before contaminants can reach the air spring bellows. The ventilation system is designed to exhaust air outward during compression movements, cushioning against the harmful effect of dust ingress before it can cause abrasion

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The system combines thin-walled elastomeric bellows material with protective sealing features and controlled ventilation mechanisms, creating a composite protective system that maintains the comfort benefits of thin walls while adding reliability through multiple functional layers

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 solution significantly reduces air intake and prevents dirt entry, maintaining the bellows' protective function and reducing the risk of damage by promoting a self-cleaning effect through controlled airflow and filtration, ensuring effective protection against contaminants.

Implementation Method 1

ventilation openings at an end of the bellows facing the undercarriage and further additional ventilation openings are provided in the bellows, which allow air to flow inside the bellows in the direction F support movement

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

the additional ventilation openings advantageously have a flow resistance that is smaller than a flow resistance of the ventilation openings

Methodology Applied
Scientific EffectFlow resistance:

Implementation Method 3

an air spring bellows made of elastomeric material clamped airtight between an air spring cover and an air spring rolling piston

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 4

Air suspension struts or air springs, which are clamped between the chassis and the body and which have an air spring bellows

Methodology Applied
Scientific EffectPneumatics:

Implementation Method 5

The air spring is under an internal overpressure during operation

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP2870378B1Air spring strut
Publication Date: 2022.04.13 CONTINENTAL TEVES AG & CO OHG
  • EP2870378B1 patent drawingFigure 1
  • EP2870378B1 patent drawingFigure 2
  • EP2870378B1 patent drawingFigure 3~4

AI summary

The invention relates to an air spring strut (1) consisting of an air spring (2) and a damper (3) for springing and damping vibrations of a motor vehicle chassis, said air spring strut being clamped between the body and the chassis of the motor vehicle, comprising an air spring bellows (6) which is clamped between an air spring cover (4) and an air spring rolling piston (5) in an air-tight manner, which is made of an elastomer material, and which rolls on the air spring rolling piston while forming a rolling fold (7); comprising an outer guide (9) which surrounds the air spring bellows (6) in a sleeve-like manner; comprising a bellows (10) which protects the rolling fold (7) from accumulating dirt and which is fixed to an outer guide (9) end facing away from the air spring cover (4); and comprising ventilation means for ventilating a space (12) surrounded by the bellows (10). The ventilation means comprise ventilation openings (13) on a bellows (10) end facing the chassis, and additional ventilation openings (14) are provided in the bellows (10), said additional ventilation openings facilitating an air flow within the bellows (10) in the direction of the chassis.