Magnetic Position Sensor for Chassis Bushing Angle Measurement

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Solution Overview

Problem

Existing position sensors used in motor vehicles for ride height measurement are susceptible to environmental damage and suffer from reduced precision due to translational movements, affecting their reliability and accuracy.

Innovation Solution

A position sensor comprising two magnetic field sensor elements arranged symmetrically relative to the central axis of a bearing bush, with an electronic evaluation circuit to distinguish between rotational and translational movements, utilizing magnetized particles or bar magnets in an elastomeric body, and a flux guide with magnetically conductive material to enhance precision and robustness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a coupling rod gear sensor is used to measure ride height, then the sensor can detect chassis movement, but it is susceptible to environmental damage from stones or ice

Engineering Contradiction:

Improvesensor durabilityVSAvoidenvironmental damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical coupling rod gear sensor with a magnetic field-based sensor system. The position sensor uses magnetic field sensor elements that detect the position of a shaft relative to a bushing through magnetic field interactions, eliminating mechanical contact points that are vulnerable to stone or ice damage while maintaining the ability to measure ride height and chassis position.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs an elastomeric body containing magnetized particles that can deform elastically. This flexible magnetic element is embedded in the bushing and can accommodate translational movements and deformations without compromising the magnetic field pattern, allowing the sensor to maintain measurement accuracy while being more resistant to environmental damage.

Inventive Principle:

Principle #30Flexible shells and thin films

2Measurement precision

If a rotary encoder in a chassis bushing is used, then the sensor can measure ride height, but measuring precision is reduced by translational movements of the bushing

Engineering Contradiction:

Improveangular position accuracyVSAvoidmeasurement stability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent uses two spatially separated magnetic field sensor elements arranged at different positions relative to the shaft. By comparing the signals from these multiple sensor elements, the evaluation circuit can distinguish between rotational movements (which change the magnetic field pattern differently at each sensor) and translational movements (which affect both sensors similarly), thereby maintaining angular position measurement precision even when the bushing experiences translational displacement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The evaluation circuit processes signals from multiple magnetic field sensor elements and uses the differential information to compensate for translational movements. By analyzing the relative changes in magnetic field strength at different sensor positions, the system can filter out translational interference and provide accurate angular position readings, effectively using feedback from multiple measurement points to correct for positional disturbances.

Inventive Principle:

Principle #23Feedback

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 provides a robust and precise angle measurement that is less sensitive to translational positioning, enabling reliable use in harsh environments and improving the accuracy of ride height sensing in motor vehicles for applications like headlamp leveling and load estimation.

Implementation Method 1

two magnetic field sensor elements 2, which are arranged opposite one another in relation to the central axis of the shaft 4 and detect both the angular position of the bushing 3 and the translational positioning of the bushing 3

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 2

utilizing magnetized particles or bar magnets in an elastomeric body

Methodology Applied

Scientific EffectMagnetism: Magnetism

Implementation Method 3

a flux guide with magnetically conductive material to enhance precision and robustness

Methodology Applied

Scientific EffectMagnetic flux conduction: Conduction (electrical)

Data Source

PatentEP2638364B1Position sensor in a chassis bush

Publication Date: 2015.08.12 CONTINENTAL TEVES AG & CO OHG

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Figure 4a~4b

AI summary

Position sensor in or on a bearing, which sensor has at least one magnetic position transmitter (1, 6, 7, 8, 9) and at least one magnetic field sensor element (2), wherein the position transmitter (1, 6, 7, 8, 9) is arranged in or at a bush (3) of the bearing, which bush accommodates a shaft (4), and the at least one magnetic field sensor element (2) contactlessly detects the magnetic field produced and/or modulated by the position transmitter, wherein the position sensor has at least two magnetic field sensor elements (2) which are spaced apart from one another and are arranged with respect to the at least one magnetic position transmitter (1, 6, 7, 8, 9) in such a manner that said elements acquire at least one item of information relating to a rotation angle position of the bearing and relating to translatory positioning of the bush (3) by detecting the magnetic field.