Electric Motor Rotor Magnetizing Device Phase Alignment
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Solution Overview
Problem
Existing methods for manufacturing electric motor rotors with phase-differentiated magnetic poles are complex and lack accuracy, making it difficult to achieve precise phase adjustments between the rotor and sensor magnets.
Innovation Solution
A method and apparatus that utilize a magnetizing device with fixed rotor-magnet and position-detecting-magnet magnetizing yokes, generating magnetic fields with a phase difference to magnetize the rotor and sensor magnets simultaneously, allowing for accurate phase adjustment without rotating the rotor, thus simplifying the manufacturing process and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the magnetizing coil is displaced to provide angular difference between magnetic poles, then the phase difference between rotor magnet and sensor magnet is achieved, but the device complexity increases and adjustment accuracy decreases
Solution Approach 1:
Instead of displacing the magnetizing coil to create phase difference, the invention inverts the approach by keeping the magnetizing device fixed and rotating the rotor during magnetization. This reversal eliminates the need for complex coil displacement mechanisms while achieving the desired phase difference through controlled rotor rotation.
Solution Approach 2:
The invention applies preliminary action by pre-positioning the magnetizing yokes in a fixed configuration before magnetization begins. The phase difference is predetermined by the fixed spatial arrangement of the yokes, eliminating the need for real-time adjustment mechanisms during the magnetization process.
2Manufacturing precision
If the magnetizing device is designed to equalize the phase of sensor magnet and rotor magnet, then phase equality is achieved, but the ability to create phase difference is lost
Solution Approach 1:
The invention introduces dynamics by enabling controlled rotation of the rotor during magnetization. This dynamic adjustment allows the system to adapt between creating phase differences and achieving phase equality, depending on the rotational position of the rotor relative to the fixed magnetizing yokes.
Solution Approach 2:
The invention changes the parameter of rotor angular position during magnetization to control the phase relationship. By varying the rotational angle of the rotor, the system can achieve different phase differences or phase equality, providing versatility without compromising precision.
3Ease of manufacture
If the rotor is rotated during magnetization to achieve phase difference, then the manufacturing process becomes simpler, but the positioning accuracy may be affected
Solution Approach 1:
The invention replaces complex mechanical displacement mechanisms with a simpler rotational positioning system. Instead of mechanically displacing magnetizing coils, the system uses controlled rotor rotation, which can be achieved through simpler mechanical means while maintaining or improving positioning accuracy.
Solution Approach 2:
The invention introduces a positioning mechanism as an intermediary between the rotor and the fixed magnetizing device. This intermediary ensures accurate angular positioning of the rotor during magnetization, maintaining manufacturing precision while simplifying the overall process.
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 approach enables the production of electric motor rotors with precise phase differences between magnetic poles, enhancing the accuracy of position detection and reducing errors, allowing for efficient and low-noise operation.
Implementation Method 1
The magnetizing device has a rotor-magnet magnetizing yoke and a position-detecting-magnet magnetizing yoke. The magnetizing device generates a magnetic field by supply of electric current through both the magnetizing yokes.
Data Source
Figure 1
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Figure 3(a)~3(b)
AI summary
A method and an apparatus for manufacturing a rotor of an electric motor are provided to obtain an electric motor with high efficiency. To this end, a rotor is magnetized by using a magnetizing device. The rotor includes a rotor magnet disposed in the circumferential direction of a rotor shaft, and a position detecting magnet disposed side-by-side with the rotor magnet with respect to the axial direction of the rotor shaft. The magnetizing device includes a rotor-magnet magnetizing yoke and a position-detecting-magnet magnetizing yoke that generate two magnetic fields. The two magnetic fields each have unlike poles arranged alternately in the circumferential direction and have a phase difference relative to each other in the circumferential direction. A phase difference is thus provided between the poles of the rotor magnet and the poles of the position detecting magnet.