Torque Sensor Shielding Flux Leakage for Precision
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Solution Overview
Problem
Existing torque sensors in vehicle steering systems experience detection errors due to flux leakage in the rotating magnetic circuit portion, which affects the precision of torque measurement.
Innovation Solution
A torque sensor design that includes a shield between the rotating magnetic circuit portion and the magnetism detector to prevent flux leakage from affecting the magnetism sensors, improving detection precision by guiding flux leakage away from the sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the magnetism sensor is disposed close to the input and output shafts to reduce the size of the apparatus, then the size of the apparatus is reduced, but the magnetism sensor is exposed to flux leakage in the rotating magnetic circuit portion which causes detection errors
Solution Approach 1:
A shield member made of magnetic material is introduced as an intermediary between the rotating magnetic circuit portion and the magnetism sensor. This shield member intercepts and redirects flux leakage away from the magnetism sensor, preventing it from affecting detection accuracy while allowing the magnetism sensor to remain positioned close to the shafts for compact apparatus size
2Measurement precision
If the magnetism sensor is disposed close to the rotating magnetic circuit portion, then the magnetic flux density detection is improved, but the flux leakage from the rotating magnetic circuit portion affects the magnetism sensor causing detection errors
Solution Approach 1:
The shield member converts the harmful flux leakage into a beneficial configuration by providing a controlled magnetic path. The shield intercepts flux leakage that would otherwise corrupt sensor readings and redirects it through the shield itself, transforming a detection interference problem into a manageable magnetic circuit design feature
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 shield effectively reduces detection errors caused by flux leakage, allowing for more precise torque measurement and enabling a smaller sensor size without compromising magnetic flux density detection.
Implementation Method 1
a shield disposed between the rotating magnetic circuit portion and the magnetism detector so as to shield the magnetism detector magnetically
Implementation Method 2
a magnetism detector that detects a magnetic flux density guided from the magnetism generation portion to the fixed magnetic circuit portion through the rotating magnetic circuit portion
Data Source
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AI summary
A torque sensor includes a magnetism generation portion that rotates together with a first shaft, a rotating magnetic circuit portion that rotates together with a second shaft, a fixed magnetic circuit portion fixed to a housing, a magnetism detector that detects a magnetic flux density guided from the magnetism generation portion to the fixed magnetic circuit portion through the rotating magnetic circuit portion in accordance with torsional deformation of the torsion bar, and a shield disposed between the rotating magnetic circuit portion and the magnetism detector in order to shield the magnetism detector magnetically.