Inductive Sensor Device for Absolute Angle Sensing
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Solution Overview
Problem
Conventional sensors for rotating elements, such as camshafts, face limitations in continuous position sensing, resolution, and sensitivity to magnetic interference, particularly failing to provide absolute angle sensing over a 360° range and instant power-on functionality.
Innovation Solution
A sensor device comprising a trigger wheel connected to the rotating element and a coil array with an excitation and receiver coil, which changes inductive coupling based on the trigger wheel's position, allowing for high-resolution absolute angle sensing and instantaneous power-on functionality, utilizing a flexible circuit carrier for easy installation and de-installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Hall-effect sensor with trigger wheel is used for position sensing, then the sensor can detect rotational position dynamically, but it cannot provide continuous absolute position sensing over 360° and fails to provide instantaneous power-on functionality
Solution Approach 1:
The patent replaces the mechanical Hall-effect sensor system with an inductive sensing system using excitation and receiver coils. This substitution enables absolute position sensing over 360° by detecting changes in inductive coupling as the trigger wheel rotates, providing continuous and instantaneous position information without relying on dynamic triggering or magnetic field sampling that limits conventional Hall-effect sensors.
2Measurement precision
If a small diameter trigger wheel is used for position sensing, then the sensor structure is compact, but the resolution is limited due to minimal gap sizes that must be taken into account
Solution Approach 1:
The patent replaces mechanical contact-based trigger wheel sampling with inductive coupling detection. This allows for higher angular resolution because the inductive sensing method can detect position changes without being constrained by physical gap sizes between sensor components and the trigger wheel teeth, enabling precise measurement even with compact trigger wheel dimensions.
3Device complexity
If conventional magnetic sensors are used for rotation detection, then the sensing mechanism is simple, but the system is highly sensitive to magnetic interference fields
Solution Approach 1:
The patent substitutes magnetic field-based Hall-effect sensing with inductive coupling-based sensing. This replacement maintains relatively simple device structure while significantly reducing sensitivity to magnetic interference fields, as the inductive method uses electromagnetic induction through coils rather than direct magnetic field detection, making the sensor more robust in electrically noisy environments.
4Measurement precision
If an inductive sensor device with excitation and receiver coils is used, then absolute position sensing over 360° with high resolution is achieved, but the device structure becomes complex and simple installation and de-installation are not possible
Solution Approach 1:
The patent combines the excitation coil, receiver coil, and associated electronic components into an integrated sensor unit that mounts directly to the trigger wheel assembly. This merging of components achieves the required 360° absolute angle sensing with high resolution while simplifying the overall structure and enabling straightforward installation and de-installation through a unified mounting interface.
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 high-resolution, continuous, and absolute angle sensing over a 360° range with improved resistance to magnetic interference and instant power-on capability, enhancing the precision and reliability of rotating element position determination.
Implementation Method 1
The excitation coil is excited by an excitation source and generates a magnetic flux. The receiver coil generates a receive signal through an inductive coupling between the excitation coil and the receiver coil.
Implementation Method 2
A change of an inductive coupling between the excitation coil and the receiver coil is ascertained as a function of a position of the trigger wheel.
Data Source
AI summary
A sensor device for ascertaining at least one rotation characteristic of a rotating element is provided. The sensor device includes at least one trigger wheel which is able to be connected to the rotating element. The rotating element and the trigger wheel have an axis of rotation. The sensor device includes at least one coil array. The coil array encompasses at least one excitation coil and at least one receiver coil. The coil array is situated on at least one circuit carrier. The trigger wheel as a trigger wheel profile. The sensor device is designed to ascertain a change in an inductive coupling between the excitation coil and the receiver coil as a function of a position of the trigger wheel. The circuit carrier is situated coaxially with the axis of rotation of the trigger wheel. The circuit carrier surrounds the trigger wheel at least partially in a circular manner.