Inclined-Substrate Magnetic Sensor for Accurate Rotation Angle Detection
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Solution Overview
Problem
Existing magnetic sensors face challenges in accurately detecting rotation angles due to deviations in the Lissajous figure of the magnetic field, which complicates the mounting structure and increases detection errors when inclined relative to the central axis of the magnet.
Innovation Solution
A magnetic sensor design with a first magnetic field detection element positioned along a substrate slope inclined at an average angle θ, ensuring the ratio of maximum to minimum magnetic field intensity (MFR) falls within specific bounds relative to the conversion coefficient (Ks), allowing for simplified mounting and reduced angle detection errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the magnetic sensor is arranged to be inclined with respect to the central axis of the magnet to detect rotation angle, then the Lissajous figure can be obtained, but the mounting structure becomes complex and angle detection errors increase
Solution Approach 1:
The patent transitions from arranging the magnetic sensor in three-dimensional space at an inclined angle to positioning it on a two-dimensional inclined surface (slope) of the substrate. This dimensional change allows the sensor to achieve the necessary geometric relationship with the magnet's central axis while maintaining a simplified planar mounting structure on the substrate, resolving the contradiction between detection accuracy and mounting complexity.
Solution Approach 2:
The patent changes the geometric parameters of the substrate by introducing an inclined surface with a specific angle range (10°-45°). This parameter modification enables the magnetic sensor to detect the rotation angle with high accuracy while the substrate's inclined surface absorbs the complexity of the mounting arrangement, preventing the overall device structure from becoming complex.
2Measurement precision
If the magnetic sensor is positioned to detect the magnetic field generated by the rotating magnet, then rotation angle detection is achieved, but deviations in the Lissajous figure cause detection errors
Solution Approach 1:
By positioning the magnetic sensor on an inclined surface of the substrate rather than in direct three-dimensional alignment with the magnet's central axis, the patent creates an optimized geometric relationship. This dimensional adjustment on the substrate surface ensures that the sensor accurately tracks the Lissajous figure generated by the rotating magnet, maintaining both high detection accuracy and reliability.
Solution Approach 2:
The patent introduces asymmetry by inclining the substrate surface at a specific angle (10°-45°) relative to the magnet's central axis. This asymmetric arrangement optimizes the magnetic field detection geometry, allowing the sensor to accurately capture the rotating magnetic field's Lissajous figure while minimizing detection errors, thus improving both accuracy and reliability.
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 design reduces angle detection errors and simplifies the mounting process by maintaining a nearly circular Lissajous figure in the magnetic field detection plane, enhancing the sensor's accuracy and ease of integration.
Implementation Method 1
a first magnetic field detection element that detects a magnetic field that is generated by a magnet that rotates about a central axis
Data Source
AI summary
Magnetic sensor 1 has magnetic field detection element 7 that detects a magnetic field that is generated by magnet 2 that rotates about central axis C; and substrate 10 that has first side P1 and second side P2 that is a reverse side of the first side P1, wherein second side P2 includes first slope PK1 that is inclined with respect to first side P1. Magnetic field detection element 7 is provided along first slope PK1. Magnet 2 is separated from central axis C and polarities of magnet 2 alternate in a circumferential direction about central axis C. First side P1 is substantially parallel to central axis C. First slope PK1 is inclined with respect to first side P1 by an average angle of 0. In a plane perpendicular to central axis C, intensity of the magnetic field where magnetic field detection element 7 is positioned changes as magnet 2 rotates, and the relation(1/Ks)×0.8≤MFR≤(1/Ks)×1.2(Ks=sin θ)is satisfied, where MFR is a ratio of a maximum value to a minimum value of the intensity of the magnetic field in the plane.