Asymmetric Sensor Magnet for Motor Position Detection
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Solution Overview
Problem
Conventional position detection magnets with identical north and south pole shapes lead to increased detection errors in rotor rotation position, affecting motor control accuracy and efficiency.
Innovation Solution
A sensor magnet with distinct thicknesses for its north and south pole parts, where the thickness of the first magnetic pole part towards the magnetic sensor is larger than that of the second pole part, optimizing magnetic flux detection and reducing errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the north pole part and south pole part have the same shape, then the manufacturing is simplified, but the detection error increases due to disturbance influence
Solution Approach 1:
The patent applies asymmetry by making the first magnetic pole part (north pole) and second magnetic pole part (south pole) have different thicknesses. Specifically, the first magnetic pole part has a greater thickness than the second magnetic pole part, creating an asymmetric structure that generates a magnetic field distribution better suited for detection by the magnetic sensor, thereby reducing detection errors while maintaining manufacturing feasibility.
Solution Approach 2:
The patent applies local quality by varying the thickness of different pole parts to optimize their local magnetic field characteristics. The first magnetic pole part is made thicker to enhance its magnetic flux contribution, while the second magnetic pole part is made thinner, creating localized differences in magnetic field strength that improve the overall detection accuracy without requiring complete redesign of the entire magnet structure.
2Device complexity
If the north pole part and south pole part have the same shape, then the device complexity is reduced, but the motor control accuracy decreases
Solution Approach 1:
The patent introduces asymmetry in the magnet structure by setting different thicknesses for the first and second magnetic pole parts. This asymmetric design improves motor control accuracy by creating a more favorable magnetic field distribution for sensor detection, while the overall structure remains relatively simple and manufacturable, thus not significantly increasing device complexity.
3Measurement precision
If the thickness of the first magnetic pole part is made larger than the second, then the detection accuracy is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent implements a simple asymmetric structure where only the thickness dimension differs between the first and second magnetic pole parts, while other dimensions and the overall configuration remain similar. This approach achieves improved detection accuracy through the thickness difference without introducing complex geometric variations, maintaining relatively simple manufacturing requirements.
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 design enhances the accuracy of motor control by minimizing detection errors and improving motor efficiency by balancing magnetic flux detection between north and south poles.
Implementation Method 1
a first magnetic pole part (81) including a magnetic pole of a first polarity and a second magnetic pole part (82) including a magnetic pole of a second polarity
Data Source
AI summary
A sensor magnet includes a first magnetic pole part including a magnetic pole of a first polarity and a second magnetic pole part including a magnetic pole of a second polarity. A thickness of the first magnetic pole part in a direction toward a magnetic sensor is larger than a thickness of the second magnetic pole part in a direction toward the magnetic sensor.