Sensing Magnet Slot Structure for Uniform Motor Position Detection
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Solution Overview
Problem
The existing motor designs suffer from non-uniform pole splitting within the sensing magnet, leading to varying sensing sensitivity depending on the position of the sensing magnet, which deteriorates motor performance.
Innovation Solution
The motor incorporates a sensing magnet with radial slots and a support plate, where the slots are formed between protruded portions, creating a uniform magnetic field by forming a polarization structure between regions of different polarities, enhancing sensing sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If radial slots are added to the sensing magnet to improve magnetic field uniformity, then sensing sensitivity is enhanced, but device complexity increases
Solution Approach 1:
The sensing magnet is segmented by introducing radial slots that divide the magnet body into multiple regions. These slots create distinct magnetic pole regions (N and S poles) that are spatially separated, resulting in uniform magnetic field distribution across the sensing surface. The segmentation transforms a single uniform magnet into a structured array of magnetic poles, directly resolving the non-uniform pole splitting issue.
Solution Approach 2:
Different regions of the sensing magnet are given different local properties through the slot configuration. The slots are strategically positioned to create alternating N and S pole regions, each with specific magnetic characteristics. This local differentiation ensures that every region of the magnet contributes uniformly to the magnetic field, enhancing sensing sensitivity while maintaining structural integrity.
2Measurement precision
If the sensing magnet structure is modified to achieve uniform pole splitting, then position detection accuracy improves, but manufacturing complexity increases
Solution Approach 1:
The radial slots are pre-formed in the sensing magnet during the manufacturing process, establishing the magnetic pole structure before the magnet is assembled into the motor. This preliminary structuring ensures that the uniform pole splitting is achieved from the outset, eliminating the need for post-manufacturing adjustments and simplifying the overall manufacturing workflow.
Solution Approach 2:
The sensing magnet employs an asymmetric slot configuration where slots are positioned at specific angular intervals rather than uniformly distributed. This asymmetric arrangement creates the desired alternating N-S pole pattern that generates uniform magnetic field distribution, while the slots themselves maintain symmetric geometric properties for ease of manufacturing.
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 ensures uniform magnetic field formation across the sensing magnet, thereby improving the sensing sensitivity and position detection accuracy of the motor.
Implementation Method 1
the magnetic field in each region of the sensing magnet can be formed uniformly by forming a polarization structure between regions with different polarities through slots
Implementation Method 2
the position of the rotor or shaft is detected by the sensor detecting the magnetic field of the sensing magnet
Data Source
AI summary
A motor comprising: a stator; a rotor disposed inside the stator; a shaft coupled to the rotor; and a sensing magnet disposed above the rotor, wherein the sensing magnet is provided with a plurality of radial slots.