Ferrite-Covered Inductive Sensor for Position Detection Through Aluminum
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Solution Overview
Problem
Existing inductive sensors using couplers are unable to determine the position of objects housed in conductive materials like aluminum due to interference, limiting their application scope.
Innovation Solution
An inductive sensor assembly featuring a substrate with transmitting and receiving coils covered by a ferrite layer, a resonator, and a magnet, which creates a 'virtual coupler' to generate eddy currents, allowing effective position determination even through conductive materials by utilizing a ferrite with high magnetic permeability and minimal eddy losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional inductive sensors with couplers are used, then position determination is achieved, but the sensor cannot penetrate conductive materials like aluminum
Solution Approach 1:
The patent introduces ferrite material as an intermediary component between the inductive sensor and the aluminum housing. The ferrite layer (0.5-5mm thick) acts as a mediator that allows magnetic field penetration through the conductive aluminum material, enabling the sensor to detect position information despite the presence of the conductive housing that would normally block the signal
Solution Approach 2:
The patent changes the magnetic properties of the environment by introducing ferrite material with specific magnetic permeability characteristics. This parameter change in the magnetic field environment enables the sensor to overcome the shielding effect of conductive materials, transforming the interaction between the sensor's magnetic field and the aluminum housing
2Adaptability or versatility
If ferrite material is added to enable penetration through conductive materials, then adaptability improves, but device complexity increases
Solution Approach 1:
The ferrite layer serves multiple functions simultaneously: it acts as a magnetic flux concentrator, provides mechanical protection for the coil assembly, and enables signal penetration through conductive materials. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity despite the added adaptability
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 accurate position determination of movable targets, including those made of aluminum, by using a ferrite-covered sensor assembly with a magnet to create a virtual coupler, enhancing the sensor's operational range and adaptability across various environments.
Implementation Method 1
A resonator is connected to the transmitting coils, a layer of ferrite covering the at least one transmitting coil and at least one receiving coil
Implementation Method 2
a layer of ferrite covering the at least one transmitting coil and at least one receiving coil
Implementation Method 3
a magnet mounted to the movable object spaced apart from the layer of ferrite
Data Source
AI summary
An inductor sensor assembly for determining to position of object includes a layer of ferrite overlaying exciting and receiving coils formed on a substrate. A magnet attached to the target produces a virtual coupler in an area of ferrite overlaying the coils. An application for a shock absorber includes a sensor module mounted in a recess in a dust cover and a magnet mounted to a cylinder tube of the shock absorber.