Overlapping Stator Teeth Layout for Magnetic Torque Sensing
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Solution Overview
Problem
Existing torque sensors in electronic power steering systems are affected by external magnetic fields, leading to inaccurate measurement of torsion in the steering shaft due to interference with the magnetic flux of Hall integrated circuits.
Innovation Solution
A sensing device with a stator and rotor configuration, where the stator teeth are designed with overlapping first and second teeth, and a magnet is positioned between them, minimizing magnetic field interference by guiding external magnetic fields away from the sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnetic type torque sensor with a collector is used to measure torque, then the torque measurement function is provided, but external magnetic fields interfere with the magnetic flux of the Hall IC through the collector, causing measurement inaccuracy
Solution Approach 1:
The patent removes the collector component from the torque sensor structure. By extracting the collector that served as a magnetic field path, external magnetic fields can no longer interfere with the Hall IC through this pathway, thereby eliminating the source of measurement inaccuracy while preserving the torque measurement function through alternative means
Solution Approach 2:
The patent introduces a magnetic shield as an intermediary component between the external environment and the Hall IC. This magnetic shield acts as a mediator that blocks or redirects external magnetic fields, preventing them from reaching the Hall IC and interfering with the magnetic flux required for accurate torque measurement
2Object-affected harmful factors
If multiple collectors are used to improve magnetic field shielding, then external magnetic field interference is reduced, but the device complexity and number of components increase
Solution Approach 1:
The patent extracts and removes the collector component entirely from the design. Instead of adding multiple collectors to reduce interference, the solution eliminates the problematic component that created the interference pathway in the first place, thereby reducing device complexity while addressing the magnetic field interference issue
Solution Approach 2:
The patent changes the magnetic field management approach by eliminating the collector structure and relying on the intrinsic magnetic properties of remaining components and strategic positioning. This parameter change in the magnetic circuit design achieves interference reduction without increasing component count or structural complexity
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 proposed configuration effectively reduces magnetic field interference, allowing for accurate torque measurement by minimizing the impact of external magnetic fields on the sensing device.
Implementation Method 1
a stator including stator teeth; and a rotor including a magnet
Implementation Method 2
the stator teeth include a first stator tooth and a second stator tooth disposed to overlap the first stator tooth in a radial direction from a center of the stator, the first stator tooth includes a plurality of first teeth and a plurality of third teeth, the second stator tooth includes a plurality of second teeth, one of the plurality of first teeth is disposed to overlap one of the plurality of second teeth in the radial direction, and the magnet is disposed between the plurality of first teeth and the plurality of third teeth
Data Source
AI summary
An embodiment may provide a sensing device comprising: a stator comprising stator teeth; and a rotor comprising magnets, wherein: the stator teeth comprise a first stator tooth and a second stator tooth arranged to overlap the first stator tooth in the radial direction from the center of the stator; the first stator tooth comprises multiple first teeth and multiple third teeth, and the second stator tooth comprises multiple second teeth; one of the multiple first teeth is arranged to overlap one of the multiple second teeth in the radial direction; and the magnets are disposed between the multiple first teeth and the multiple third teeth, respectively.