Rotor Conductive Member Segmentation for Rotary Electric Machine
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Solution Overview
Problem
Conventional rotors for rotary electric machines face challenges in manufacturing complexity and demagnetization of permanent magnets due to heat generation and harmonic magnetic flux issues, particularly with the use of cylindrical high-conductivity members that require laborious manufacturing and can lead to demagnetization when divided into conduction portions.
Innovation Solution
A rotor design featuring a conductive member with higher conductivity than the permanent magnets, wrapped around the rotor core and magnets, with opposing portions separated by a gap, positioned within the inter-magnet region to link harmonic magnetic flux and reduce heat transmission, facilitating easy manufacturing and minimizing demagnetization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cylindrical high-conductivity member is used to suppress demagnetization, then demagnetization is suppressed, but manufacturing becomes laborious and diameter increases
Solution Approach 1:
The conductive member is divided into multiple conduction portions arranged in the circumferential direction, with gaps between them. This segmentation simplifies manufacturing by allowing separate fabrication and assembly of smaller components, while still providing sufficient eddy current paths to suppress demagnetization without requiring a complete cylindrical structure
Solution Approach 2:
The conductive member transitions from a three-dimensional cylindrical structure to a two-dimensional annular structure with circumferential gaps. This dimensional change reduces manufacturing complexity and material requirements while maintaining the essential function of providing eddy current paths for demagnetization suppression
2Ease of manufacture
If the high-conductivity member is divided into conduction portions, then manufacturing is facilitated, but gaps allow harmonic magnetic flux to reach the permanent magnet causing demagnetization
Solution Approach 1:
The conductive member is positioned specifically within the inter-magnet region where gaps between permanent magnets exist. This local positioning ensures that the gaps in the conductive member align with regions where harmonic magnetic flux is already minimized, preventing demagnetization while maintaining manufacturing simplicity
Solution Approach 2:
The gaps between conduction portions, which could potentially allow harmful harmonic magnetic flux to reach the permanent magnet, are strategically positioned within inter-magnet regions where they actually benefit from the natural magnetic flux distribution, converting a potential harm into a manufacturing advantage
3Reliability
If conduction portions are brought into contact to prevent harmonic magnetic flux from reaching the permanent magnet, then demagnetization is suppressed, but contact resistance increases causing heat generation
Solution Approach 1:
The conductive member maintains gaps between conduction portions rather than bringing them into contact. This segmentation eliminates contact resistance and heat generation at interfaces, while the gaps are positioned in inter-magnet regions where they do not compromise demagnetization suppression
Solution Approach 2:
The conductive member acts as an intermediary that provides eddy current paths for demagnetization suppression without requiring direct contact between components. The gaps eliminate contact resistance issues while the conductive portions still effectively intercept harmonic magnetic flux
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
The solution allows for simplified manufacturing and effective suppression of demagnetization by redirecting harmonic magnetic flux through the conductive member, reducing heat generation and contact resistance, thereby enhancing the stability of permanent magnets.
Implementation Method 1
eddy currents are generated in the high-conductivity member, and magnetic flux generated by the eddy currents cancels out the harmonic magnetic flux of the carrier frequency component
Implementation Method 2
magnetic flux generated by the eddy currents cancels out the harmonic magnetic flux of the carrier frequency component
Implementation Method 3
a conductive member with higher conductivity than the permanent magnets, wrapped around the rotor core and magnets
Data Source
AI summary
In a rotary electric machine, a conductive member surrounds a shaft and a plurality of permanent magnets provided on an outer peripheral portion of the shaft as a whole, and a holding member surrounds the shaft, the plurality of permanent magnets, and the conductive member as a whole. A conductivity of the conductive member is higher than a conductivity of the permanent magnet. The conductive member includes first and second opposing portions that oppose each other via a gap in a circumferential direction. An inter-opposing portion region existing between the first and second opposing portions is positioned within a circumferential direction range of an inter-magnet region existing between permanent magnets that are adjacent to each other in the circumferential direction.