Air Spring Assembly with Force Sensor for Load Measurement

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Solution Overview

Problem

Current air spring systems in vehicles, especially trucks, face challenges in accurately and efficiently measuring load capacity due to high calibration efforts, material fatigue, and non-linear pressure-load relationships, leading to systematic errors in load determination.

Innovation Solution

An air spring arrangement with a strength sensor and computing unit that records axial and cross forces using capacitive sensor elements, allowing for precise determination of load capacity and transmission to a central unit, enabling more accurate load calculation and reducing calibration needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If air spring pressure is used to determine load capacity, then load measurement is possible, but measurement precision deteriorates due to non-linear pressure-load relationship and systematic errors

Engineering Contradiction:
Improveload capacity measurement precisionVSAvoidmeasurement reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the indirect pressure-based measurement system with a direct force sensor (Kraftsensor) that mechanically measures the load capacity. This substitution eliminates the non-linear pressure-load relationship and systematic errors by directly sensing the mechanical force acting on the air spring, providing both high precision and reliability in load determination.

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

Solution Approach 2:

The patent introduces a force sensor as an intermediary element between the air spring and the measurement system. This intermediary directly captures the load capacity force, serving as a reliable mediator that translates mechanical load into measurable signals without the inaccuracies of pressure-based indirect measurement.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If individual calibration factors are applied to each air spring, then load determination is possible, but device complexity increases due to high calibration effort per air spring

Engineering Contradiction:
Improveload determination accuracyVSAvoidcalibration system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The force sensor performs self-measurement of load capacity without requiring external calibration factors for each air spring. The sensor automatically determines the actual load by directly sensing the force, eliminating the need for complex individual calibration procedures and reducing system complexity while maintaining accuracy.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent changes the measurement parameter from indirect pressure readings requiring calibration factors to direct force sensing. This parameter change eliminates the need for individual calibration factors, simplifying the system while providing accurate load determination through direct mechanical measurement.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If calibration is repeated over time to account for material fatigue, then measurement reliability is improved, but loss of time increases due to repeated calibration efforts

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidcalibration time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The force sensor provides continuous self-measurement of load capacity without requiring periodic recalibration. The sensor maintains measurement reliability over time through its direct mechanical sensing capability, which is not affected by material fatigue in the same way pressure-based systems are, eliminating time-consuming recalibration cycles.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The force sensor enables continuous accurate measurement of load capacity without interruption for calibration. The direct force measurement mechanism maintains reliability over time, allowing the system to operate continuously without the downtime required for repeated calibration procedures.

Inventive Principle:
Principle #20Continuity of useful action

4Measurement precision

If load capacity calculation considers installation situation and spring height, then measurement precision improves, but device complexity increases due to additional measurement requirements

Engineering Contradiction:
Improveload capacity measurement precisionVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The force sensor directly measures load capacity through mechanical force sensing, replacing the complex calculation system that required multiple parameters (installation situation, spring height, pressure readings). This substitution provides high precision measurement while simplifying the system by eliminating the need for multiple sensors and complex computational algorithms.

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

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

This solution provides a more precise, cost-effective, and reliable method for determining load capacity, reducing errors and calibration efforts, and allowing for wireless transmission of load data, enhancing the accuracy of vehicle loading assessments.

Implementation Method 1

with a majority of strength sensor elements, preferably at least seven strength sensor elements, which are arranged flat compared to the first connection element... The capacitive strength sensor has a majority of capacitive strength sensor elements in the form of measuring electrodes

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3915812B1Air spring assembly
Publication Date: 2022.11.30 CONTITECH LUFTEDERSYSTEME GMBH
  • EP3915812B1 patent drawingFigure 1
  • EP3915812B1 patent drawingFigure 2~3
  • EP3915812B1 patent drawingFigure 4~5

AI summary

The present invention relates to an air spring arrangement (1, 2, 3, 4) with at least one air spring (1) with a first connecting element (11) which is designed to be connected to a first body (50), with a second connecting element (12) which is designed to be connected to a second body, and with a bellows (13) which is arranged between the first connecting element (11) and the second connecting element (12) along a longitudinal axis (X) and which airtightly encloses an air-filled interior space (10).The air spring arrangement (1, 2, 3, 4) is characterized in that at least the first connecting element (11) facing away from the bellows (13) along the longitudinal axis (X) has at least one force sensor (14) which is designed to detect at least one axial force (Fa) and at least one transverse force (Fq) relative to the first body (50) with respect to magnitude and direction, and furthermore with at least one computing unit (3) which is designed to determine a resultant load-bearing capacity (Ft) of the air spring (1) from the detected forces (Fa, Fq).