Rotor Core Bridge Portions for Reducing Magnetic Flux Leakage
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Solution Overview
Problem
Conventional permanent-magnet-embedded electric motors suffer from insufficient reduction of magnetic flux leakage due to incomplete coverage of magnetic leakage paths in their rotor core structures.
Innovation Solution
The motor design incorporates a rotor core with laminated steel plates featuring magnet-embedding holes and bridge portions with thinner plate thickness, connected by thinned link portions, which increase magnetic resistance across the entire magnetic path, reducing magnetic flux leakage without increasing overall magnetic resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the plate thickness of bridge portions is reduced to decrease magnetic flux leakage, then magnetic flux leakage is reduced, but the mechanical strength of the rotor core is weakened
Solution Approach 1:
The invention applies local quality by creating thinned link portions only in specific regions where magnetic flux leakage occurs, while maintaining the original plate thickness in other bridge portions to preserve mechanical strength. This selective thinning allows the structure to have different properties in different locations - thin in areas needing magnetic flux control, and thick in areas needing structural support
Solution Approach 2:
The invention segments the bridge portions into multiple sections, identifying and thinning only the link portions that connect magnet-embedding holes and are responsible for magnetic flux leakage. This segmentation allows targeted modification of specific regions without affecting the overall structural integrity of the rotor core
2Object-generated harmful factors
If the plate thickness of bridge portions is reduced to increase magnetic resistance, then magnetic flux leakage is reduced, but the overall magnetic resistance in the magnetic path increases
Solution Approach 1:
The invention applies local quality by creating thinned link portions only in specific regions where magnetic flux leakage occurs, while maintaining the original plate thickness in other bridge portions to preserve mechanical strength. This selective thinning allows the structure to have different properties in different locations - thin in areas needing magnetic flux control, and thick in areas needing structural support
Solution Approach 2:
The invention segments the bridge portions into multiple sections, identifying and thinning only the link portions that connect magnet-embedding holes and are responsible for magnetic flux leakage. This segmentation allows targeted modification of specific regions without affecting the overall structural integrity of the rotor core
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 effectively minimizes magnetic flux leakage and enhances torque production while maintaining mechanical strength, allowing for a more efficient and robust electric motor operation.
Implementation Method 1
A magnetic flux produced by the permanent magnet passes through the bridge portions and flows to the adjoining permanent magnet
Implementation Method 2
a magnetic resistance in the entire magnetic path does not increase even when the plate thickness of only the bridge portions are reduced. Therefore, a reduction of the magnetic flux leakage can be achieved by connecting the bridge portions with the thinned link portion, which decrease the plate thickness of the bridge portions in a manner to increase the magnetic resistance in the entire magnetic path
Data Source
AI summary
A permanent-magnet-embedded electric motor includes a stator having a coil wound on a stator core, and a rotor disposed rotatably inside the stator through a gap to an inner circumferential surface of the stator core. The rotor is provided with a rotor core formed of laminated steel plates having a plurality of magnet-embedding holes, and a permanent magnet housed and retained in each of the magnet-embedding holes. A thickness of the bridge portions formed between edges of the magnet-embedding holes and an outer circumference of the rotor core, and a thickness of a thinned link portion connecting adjoining two of the bridge portions are thinner than a thickness of the steel plates.