Torque Sensor Magnetic Shielding for Electromagnetic Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing torque sensors face challenges in accurately detecting torque between members due to electromagnetic coupling interference, which affects the precision of measurements, particularly in applications like automotive steering columns.
Innovation Solution
The torque sensor employs a configuration with multiple channels, each featuring an excitation coil, oscillator circuit, and receiver structures with specific geometric and material arrangements to minimize electromagnetic coupling, including phase-shifted time-varying magnetic fields and geometric decoupling of rotor targets, to enhance measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple channels are used in the torque sensor, then measurement accuracy is improved, but electromagnetic coupling interference increases
Solution Approach 1:
A magnetic shield is introduced as an intermediary component between the excitation coil and receiver structures. This magnetic shield acts as a mediator that directs and controls the magnetic field paths, allowing multiple channels to operate simultaneously while preventing electromagnetic coupling interference between them.
Solution Approach 2:
The magnetic shield is positioned at specific locations between the excitation coil and receiver structures to create localized field control. By placing the shield strategically in the magnetic field path, the patent achieves channel isolation where needed while maintaining measurement sensitivity in other areas.
2Power
If the number of receiver structures is increased, then signal strength is improved, but electromagnetic interference between channels increases
Solution Approach 1:
The magnetic shield serves as a mediator that allows multiple receiver structures to be positioned closer to the excitation coil for stronger signals, while simultaneously blocking electromagnetic coupling between adjacent channels. The shield creates distinct magnetic field zones that prevent interference.
Solution Approach 2:
The magnetic shield divides the magnetic field into separate zones for each channel. By segmenting the field paths, the patent enables multiple receiver structures to operate in parallel with enhanced signal strength without experiencing cross-channel electromagnetic interference.
3Reliability
If the excitation coil is positioned closer to the receiver structures, then coupling strength is improved, but electromagnetic coupling between channels increases
Solution Approach 1:
The magnetic shield is positioned between the excitation coil and receiver structures to create controlled magnetic field paths. This intermediary component allows the coil and receivers to be positioned close together for strong coupling while preventing electromagnetic energy from coupling between adjacent channels.
Solution Approach 2:
The magnetic shield changes the magnetic field distribution parameters by concentrating flux through specific paths. This parameter change enables strong inductive coupling between the excitation coil and receiver structures while simultaneously reducing electromagnetic coupling between different channels.
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 configuration significantly improves the accuracy of torque detection by reducing electromagnetic interference, leading to more precise measurements in applications such as automotive steering columns.
Implementation Method 1
at least one excitation coil... configured to generate a period voltage signal and energize the excitation coil with the periodic voltage signal
Implementation Method 2
The first rotor target can be configured to affect a strength of the inductive coupling between the excitation coil and the first receiver
Data Source
AI summary
A torque sensor can be configured to detect the positions of rotor targets relative to the position of respective receiver structures. A torque sensor can include an oscillator circuit coupled to an excitation coil. The oscillator circuit can be configured to generate a periodic voltage signal and energize the excitation coil with the periodic voltage signal. The inductive torque sensor can include a stator circuit board including receivers with receiver structures that are periodically repeated. The inductive torque sensor can include rotor targets coupled to respective rotors, the rotor targets can be configured to affect the strength of the inductive coupling between the excitation coil and the respective receivers. The inductive torque sensor can include processing circuitry configured to provide signals associated with positions of the rotor targets relative to their respective receiver structures.