Motor Hall Element Positioning for Detection Accuracy
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Solution Overview
Problem
Existing rotating electric machines face challenges in maintaining position detection accuracy of rotor magnets due to errors in sensor attachment and interference from magnetic noise from coils, leading to deteriorated position direction accuracy.
Innovation Solution
The motor design includes a shaft centered on a vertical axis with a bearing mechanism, an armature, a bracket, and a covered cylindrical rotor with a Hall element mounted on a circuit board held by the bracket, positioned lower than the rotor magnet to reduce attachment errors and magnetic noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the Hall element is mounted on a circuit board attached to the stator core, then the position detection function is achieved, but the position detection accuracy deteriorates due to cumulative attachment errors
Solution Approach 1:
The detection system is divided into two independent parts: the Hall element fixed to the stator core and the circuit board separately mounted. This segmentation allows each component to be positioned independently, eliminating cumulative attachment errors that would occur if multiple components were chained together through multiple attachment points.
Solution Approach 2:
A protrusion on the stator core serves as an intermediary reference point that directly receives both the Hall element and the circuit board. This intermediary structure provides a common reference frame, ensuring that both components are positioned relative to the same基准, thereby improving detection accuracy.
2Ease of manufacture
If the Hall element is disposed between teeth portions, then the structural integration is improved, but the detection accuracy deteriorates due to magnetic noise from coils
Solution Approach 1:
The Hall element is extracted from the region between the teeth portions and relocated to a position on the stator core that is远离 from the coil assemblies. This extraction removes the Hall element from the high magnetic noise environment, thereby improving detection accuracy while maintaining structural integration through direct mounting on the stator core.
3Stability of the object's composition
If multiple attachment points are used for the circuit board and Hall element, then the structural stability is improved, but the position detection accuracy deteriorates due to cumulative errors
Solution Approach 1:
The mounting positions of the Hall element and the circuit board are merged onto a single reference structure (the stator core protrusion). This merging of reference frames eliminates the cumulative errors that would arise from using separate attachment points, while the overall structural stability is maintained through the rigid stator core structure.
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 improves the position detection accuracy of the rotor magnet by minimizing attachment errors and electromagnetic noise interference, enhancing the overall detection precision.
Implementation Method 1
a Hall element 271 mounted on a circuit board 27 held by the board holding portion 216
Data Source
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AI summary
A motor includes a shaft centered on a center axis oriented in a vertical direction; a bearing mechanism rotatably supporting the shaft; an armature disposed radially outward of the bearing mechanism; a bracket to which the bearing mechanism and the armature are fixed; a covered cylindrical rotor connected to the shaft; and a circuit board on which a Hall element is mounted. The rotor includes a rotor magnet radially opposed to the armature radially outward of the armature. The bracket includes a cylindrical portion having an outer peripheral surface to which the armature is fixed, a bracket bottom portion extending radially outward from a lower end portion of the cylindrical portion, a bracket side wall portion extending upward from an outer peripheral portion of the bracket bottom portion, and a board holding portion connected to the bracket side wall portion. The circuit board is held by the board holding portion. The Hall element is held by the bracket side wall portion.