Linear Hall Element Motor with Offset Magnet for Phase Detection
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Solution Overview
Problem
Three-phase brushless motors require multiple Hall elements for phase and rotation period detection, making it difficult to achieve space saving and cost reduction due to the complexity and number of components needed.
Innovation Solution
A motor design utilizing a linear Hall element and an offset magnet, where the linear Hall element detects a linear change in magnetic flux density, allowing for the detection of both rotation period and phase switching with a single Hall element, reducing the number of components required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple Hall elements are used for phase and rotation period detection, then detection accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies multi-functionality by enabling a single Hall element to perform both phase detection and rotation period detection functions. The Hall element detects magnetic flux density changes from multiple magnets including one offset magnet, and the control unit processes these signals to extract both phase switching information and rotation period information, thereby eliminating the need for separate detection sensors for each function.
Solution Approach 2:
The patent merges the previously separate phase detection and rotation period detection functions into a single detection system. By positioning one magnet offset from the others and using a single Hall element to detect magnetic flux density changes from all magnets, the system combines multiple detection functions into one sensor assembly, reducing component count while maintaining detection capabilities.
2Reliability
If multiple Hall elements are used for phase and rotation period detection, then detection reliability is improved, but manufacturing cost increases
Solution Approach 1:
The control unit applies multi-functionality by processing signals from a single Hall element to achieve both phase detection and rotation period detection. The control unit identifies phase switching timing based on magnetic flux density changes and simultaneously detects rotation period based on the offset magnet's position, thereby maintaining detection reliability while reducing component count and manufacturing cost.
Solution Approach 2:
The patent changes the spatial parameter of magnet arrangement by positioning one magnet offset from the others. This parameter change enables the Hall element to detect distinct magnetic flux density patterns that allow the control unit to differentiate between phase switching events and rotation period information, maintaining detection reliability with fewer components.
3Measurement precision
If multiple Hall elements are used for phase and rotation period detection, then detection precision is improved, but space consumption increases
Solution Approach 1:
The patent applies multi-functionality by enabling a single Hall element to perform both phase detection and rotation period detection. The Hall element is positioned to detect magnetic flux density changes from multiple magnets including the offset magnet, and the control unit processes these signals to extract both phase switching timing and rotation period information, thereby achieving precise detection with minimal space consumption.
Solution Approach 2:
The patent merges phase detection and rotation period detection functions into a single sensor location. By using one Hall element to monitor magnetic flux density changes from all magnets and processing these signals centrally in the control unit, the system combines multiple detection functions into one spatial location, eliminating the need for multiple separate sensors and reducing overall space 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 enables efficient detection of rotation period and phase switching, facilitating further space saving and cost reduction by minimizing the number of Hall elements needed, while maintaining accurate detection capabilities.
Implementation Method 1
a Hall element is provided among the stators, and the Hall element outputs a signal representing a magnetic flux density detected by the Hall element
Implementation Method 2
one of the plurality of magnets is an offset magnet arranged offset from the other magnets along a central axis of the cylindrical outer rotor
Data Source
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AI summary
A motor which is capable of realizing further space saving and cost reduction. A cylindrical outer rotor 11 is rotatable around a central axis CL thereof. A plurality of magnets 13 are arranged at equal intervals on an inner circumferential surface of the outer rotor 11. Three Hall elements 15 to 17 are arranged to oppose the respective magnets 13 and detect switching of magnetic poles caused by movement of the respective magnets 13 passing through each vicinity of the Hall elements 15 to 17 when the outer rotor 11 rotates. The Hall element 17 is comprised of a linear Hall element that outputs a linear signal representing a linear change of a magnetic flux density caused by movement of the respective magnets 13. One of the respective magnets 13 is arranged offset along the central axis CL as compared to the other magnets 13.