Dual-Layer Rotor Bridge Structure for Flux Leakage and Strength
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Solution Overview
Problem
Electric motors face a trade-off between reducing magnetic flux leakage and maintaining mechanical strength against centrifugal forces, as narrower bridges reduce leakage but weaken the rotor, while wider bridges increase efficiency but decrease mechanical strength.
Innovation Solution
The design incorporates specific dimensions and configurations for the first and second rotor cores, including flux barrier parts and bridges, to optimize the balance between magnetic flux reduction and mechanical strength, ensuring that the sum of certain bridge dimensions and thicknesses in the first rotor core exceeds those in the second rotor core, thereby enhancing efficiency while maintaining mechanical integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the width of the bridge is decreased to reduce magnetic flux leakage, then magnetic flux leakage is reduced, but the mechanical strength of the rotor to centrifugal force decreases
Solution Approach 1:
The patent introduces a dual-layer rotor core structure with first and second rotor cores stacked in the axial direction. Each layer has its own bridges, creating a three-dimensional bridge configuration. This dimensional change allows the bridges to provide both magnetic flux blocking functionality and enhanced mechanical strength through the combined effect of multiple layers, resolving the contradiction between reducing leakage and maintaining strength.
Solution Approach 2:
The patent employs a composite structure where two rotor cores with different bridge configurations are combined in the axial direction. The first rotor core has bridges with specific width and thickness parameters, while the second rotor core has different parameters, creating a composite structure that optimizes both magnetic performance and mechanical strength by leveraging the complementary characteristics of each layer.
2Strength
If the width of the bridge is increased to increase mechanical strength, then mechanical strength is increased, but magnetic flux leakage increases
Solution Approach 1:
By stacking two rotor cores in the axial direction with different bridge configurations, the patent creates a three-dimensional solution where the combined bridge structure provides sufficient mechanical strength while the distributed magnetic flux blocking across layers reduces overall magnetic flux leakage, resolving the contradiction between strength and leakage.
Solution Approach 2:
The composite structure of first and second rotor cores with different bridge parameters allows optimization of each layer's function. The first rotor core can be designed for mechanical strength while the second rotor core focuses on magnetic flux blocking, and their combination achieves both objectives simultaneously.
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 effectively reduces magnetic flux leakage while maintaining the mechanical strength of the rotor, particularly during high-speed rotation, thereby enhancing the overall efficiency of the electric motor.
Implementation Method 1
spaces are provided on both ends of permanent magnets of a rotor of an electric motor in order to reduce magnetic flux leakage in the rotor (e.g., leakage of magnetic flux from permanent magnets of magnetic pole parts of the rotor to adjacent magnetic pole parts)
Implementation Method 2
a mechanical strength of the rotor to a centrifugal force generated in the rotor
Data Source
AI summary
An electric motor includes: a permanent magnet; a rotor including a first rotor core having a first electrical steel sheet and a second rotor core having a second electrical steel sheet; and a stator including a stator core. The first electrical steel sheet is located outside the stator core. A relationship among a minimum width BL1 of a first left bridge, a thickness tL1 of the first left bridge, a minimum width BR1 of a first right bridge, a thickness tR1 of the first right bridge, a minimum width BL2 of a second left bridge, a thickness tL2 of the second left bridge, a minimum width BR2 of a second right bridge, and a thickness tR2 of the second right bridge satisfies (BL1×tL1+BR1×tR1)>(BL2×tL2+BR2×tR2).