Sensing Device Magnetic Shielding Torque Measurement
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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 degrees due to magnetic flux interference.
Innovation Solution
The sensing device incorporates a collector disposed between stator teeth to prevent external magnetic fields from interfering, and a magnet is rotatably positioned between the stator teeth to charge the stator teeth, enhancing magnetic flux collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the collector is disposed outside the stator tooth to simplify the structure, then the device complexity is reduced, but the torque sensor is affected by external magnetic fields causing measurement inaccuracy
Solution Approach 1:
The patent introduces a magnetic shield as an intermediary component between the external magnetic field and the Hall integrated circuit. This magnetic shield selectively blocks external magnetic fields while allowing the magnetic flux from the stator tooth to pass through, thereby protecting the sensor without interfering with the measurement function
Solution Approach 2:
The patent divides the stator structure into multiple segments including stator teeth and inter-tooth regions. The collector is segmented to extend into the inter-tooth regions, creating multiple pathways for magnetic flux collection while the magnetic shield is also segmented to correspond with these regions, enabling localized protection against external magnetic fields
2Quantity of substance
If the collector serves as a passage for magnetic fields to simplify flux collection, then the magnetic flux value is improved, but external magnetic fields interfere with the Hall integrated circuit causing output value changes
Solution Approach 1:
The magnetic shield acts as a selective intermediary that allows desired magnetic flux from the stator tooth to pass through to the Hall integrated circuit while blocking harmful external magnetic fields. This mediator component distinguishes between useful and harmful magnetic fields based on their source and direction
Solution Approach 2:
The magnetic shield is strategically positioned only in regions where external magnetic field interference occurs, while leaving other regions open for magnetic flux collection. The collector extends into inter-tooth regions to locally enhance flux collection without compromising the overall measurement accuracy
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 effectively minimizes magnetic interference, allowing for accurate torque measurement and reducing the impact of external magnetic fields on the sensing device.
Implementation Method 1
a magnet is rotatably positioned between the stator teeth to charge the stator teeth, enhancing magnetic flux collection
Implementation Method 2
the collector serves as a passage of the magnetic field in the structure
Implementation Method 3
the collector affects a magnetic flux value of a Hall integrated circuit (IC)
Data Source
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AI summary
According to an embodiment, a sensing device includes a stator including a stator tooth and a rotor including a magnet, wherein the stator tooth includes a first stator tooth and a second stator tooth disposed inside the first stator tooth, the first stator tooth includes a plurality of first teeth, the second stator tooth includes a plurality of second teeth, the magnet includes a first pole and a second pole, the first tooth overlaps the second tooth in a radial direction from a center of the stator, and a first angle formed between two ends of the first pole based on the center of the stator is the same as a second angle formed between two ends of the first tooth based on the center of the stator.