Capacitive Torque Sensor Using Rotating Dielectric
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Solution Overview
Problem
Magnetic torque sensors face high manufacturing costs and complex assembly requirements due to the use of expensive components like magnets and Hall sensors, which can lead to drift issues and are sensitive to environmental factors.
Innovation Solution
A capacitively measuring torque sensor system that uses a rotation angle-dependent change in permittivity between capacitor plates to determine torque, eliminating the need for magnets and Hall sensors, with a design that allows for cost-effective manufacturing and robust assembly, and is less affected by environmental influences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic field-sensitive sensor elements (Hall sensors) and magnet rings are used for torque sensing, then high angular resolution is achieved, but manufacturing costs increase and device complexity increases
Solution Approach 1:
The patent replaces the magnetic measurement system (Hall sensors and magnet rings) with a capacitive measurement system. The capacitive sensor uses capacitor plates and a dielectric element that rotates with the shaft, eliminating the need for expensive magnetic components while achieving the same angular resolution through capacitance changes caused by the rotating dielectric.
Solution Approach 2:
The patent changes the measurement parameter from magnetic field detection to capacitance detection. By using a dielectric element whose position relative to capacitor plates changes with rotation, the system measures angular position through capacitance variations, providing a cost-effective alternative to magnetic sensing.
2Measurement precision
If Hall sensors are used for magnetic field detection, then high angular resolution is achieved, but assembly complexity increases due to high positional accuracy requirements
Solution Approach 1:
The patent replaces the magnetic measurement system (Hall sensors and magnet rings) with a capacitive measurement system. The capacitive sensor uses capacitor plates and a dielectric element that rotates with the shaft, eliminating the need for expensive magnetic components while achieving the same angular resolution through capacitance changes caused by the rotating dielectric.
3Measurement precision
If Hall sensors and magnet rings are used for torque sensing, then high angular resolution is achieved, but sensor drift occurs due to sensitivity to environmental factors
Solution Approach 1:
The patent replaces the magnetic measurement system (Hall sensors and magnet rings) with a capacitive measurement system. The capacitive sensor uses capacitor plates and a dielectric element that rotates with the shaft, eliminating the need for expensive magnetic components while achieving the same angular resolution through capacitance changes caused by the rotating dielectric.
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 contactless, noise-free, and cost-effective torque measurement system with improved angular resolution and reduced sensitivity to environmental factors, enabling reliable operation in various applications, such as electronic steering assistance in vehicles.
Implementation Method 1
a rotation angle-dependent, typically spatial change of the rotatable dielectric situated between capacitor plates of a capacitor. This results in a change in the permittivity ε, which is also referred to as the dielectric conductivity, via which a change in the capacitance of the capacitor may be brought about
Implementation Method 2
The two plates are stationarily mounted on the shaft. Thus, a capacitance between the two plates is defined by an angle-dependent position of the dielectric rotor
Data Source
AI summary
A rotation angle sensor which has at least one capacitor having capacitor plates and a dielectric designed as a disk. The disk is situated between the capacitor plates, and fills out differently sized surface portions between the capacitor plates, depending on the rotation angle. The rotation angle sensor is designed to determine the rotation angle as a function of a measured value of the capacitance of the at least one capacitor.