Flexible Bellows Aging Detection via Gas Pressure and Displacement

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Solution Overview

Problem

It is challenging to accurately determine the aging of flexible bellows in vehicle suspension arrangements, leading to premature replacement and unnecessary discarding of functional components.

Innovation Solution

A method involving the determination of the distance moved by a portion of the flexible bellows under external load, gas pressure level measurement, and comparison with predetermined threshold levels to assess the aging of the flexible bellows, using a control unit that can adapt reference values based on specific bellows characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pre-set replacement intervals are used for the flexible bellows, then the suspension arrangement maintains reliability, but the flexible bellows is replaced prematurely and functional components are unnecessarily discarded

Engineering Contradiction:
Improvesuspension performanceVSAvoidfunctional bellows discarded
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent replaces mechanical/time-based replacement intervals with a sensor-based monitoring system that uses gas pressure sensors and level indicators to detect actual bellows degradation. This substitution allows for condition-based replacement decisions rather than predetermined interval replacement, preventing premature disposal of functional bellows while maintaining suspension reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system implements continuous feedback monitoring through gas pressure sensors and level indicators that track the bellows' operational state. By comparing real-time measurements against threshold values, the system provides feedback on bellows degradation, enabling informed replacement decisions that prevent unnecessary discarding of functional components while ensuring reliability when degradation occurs.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If the flexible bellows is monitored continuously, then the aging can be precisely determined, but the device complexity increases

Engineering Contradiction:
Improveaging determination accuracyVSAvoidmonitoring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The monitoring system is segmented into distinct functional components: gas pressure sensors for measuring internal pressure, level indicators for tracking bellows expansion state, and a control unit for processing data. This segmentation allows each component to perform a specific measurement function, achieving precise aging determination through multiple independent measurements rather than a single complex sensor system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control unit serves multiple functions: it receives data from both gas pressure sensors and level indicators, processes both types of measurements, compares results against threshold values, and determines replacement timing. This multi-functionality consolidates complex monitoring tasks into a single control unit, reducing overall system complexity while maintaining measurement precision.

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

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

Enables continuous online monitoring of flexible bellows characteristics, allowing for precise determination of aging and optimal replacement timing, reducing unnecessary replacements and improving suspension performance.

Implementation Method 1

a flexible bellows, or flex member, which is connected to the vehicle chassis, and a piston which is connected to the wheel axle. The chassis can be raised and lowered in relation to the wheel axle by means of inflating or deflating air into the space formed by the flexible bellows

Methodology Applied
Scientific EffectGas compression: Compression

Implementation Method 2

the flexible bellows is thus arranged to roll up and down on the piston when inflating/deflating air therein

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP3619061B1Method for determining aging of a vehicle suspension arrangement
Publication Date: 2021.06.02 VOLVO TRUCK CORP
  • EP3619061B1 patent drawingFigure 1
  • EP3619061B1 patent drawingFigure 2
  • EP3619061B1 patent drawingFigure 3~4

AI summary

The present invention relates to a method for determining aging of a vehicle suspension arrangement (100) arranged between a frame and a wheel axle of a vehicle, said suspension arrangement (100) comprising a flexible bellows (102) for damping motions from said wheel axle, the method comprising the steps of determining a distance moved by a portion of the flexible bellows (102) when the suspension arrangement is exposed to an external load; determining a gas pressure level within said flexible bellows (102) when the portion of said flexible bellows (102) has moved said distance; determining a relationship between the determined gas pressure level within said flexible bellows and said distance moved by the portion of the flexible bellows; comparing the relationship with a predetermined threshold level; and determining that said flexible bellows is aged if a difference between the relationship and the predetermined threshold level is outside a predetermined threshold range.