Rotor Core Permeability Layout for Stable Electric Motor Torque
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Solution Overview
Problem
Conventional electric motor rotors face challenges in achieving high average torque due to magnetic flux leakage and torque fluctuations, requiring precise alignment and high manufacturing accuracy.
Innovation Solution
The rotor design features a central core with permanent magnets arranged on its outer surface, an outer peripheral core with magnetic material attached to intermediate portions to concentrate magnetic flux, and terminal cores with lower magnetic permeability to redirect leakage flux radially, reducing torque fluctuations and improving average torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional rotor design with uniform magnetic permeability is used, then manufacturing is simpler, but torque fluctuations increase and average torque decreases
Solution Approach 1:
The patent applies local quality by creating regions with different magnetic permeability characteristics within the rotor core. Specifically, it uses terminal cores with lower magnetic permeability at the ends of the rotor and an outer peripheral core with higher magnetic permeability in the intermediate portions. This local differentiation allows magnetic flux to be concentrated in specific regions, reducing leakage flux and stabilizing torque output, thereby improving average torque without requiring complex external control systems.
2Power
If precise alignment of core pieces is required, then magnetic flux distribution improves, but manufacturing precision requirements increase and cost increases
Solution Approach 1:
The patent changes the magnetic permeability parameter of different core regions to achieve the desired magnetic flux distribution. By using terminal cores with lower magnetic permeability and an outer peripheral core with higher magnetic permeability, the design inherently guides magnetic flux concentration without relying on precise mechanical alignment of core pieces. This parameter-based control reduces manufacturing precision requirements while maintaining effective magnetic flux concentration.
3Stability of the object's composition
If terminal cores with lower magnetic permeability are used, then leakage flux is redirected radially and torque fluctuations are reduced, but magnetic circuit design complexity increases
Solution Approach 1:
The patent segments the rotor core into distinct functional regions: terminal cores at the ends with lower magnetic permeability and an outer peripheral core in the intermediate portions with higher magnetic permeability. This segmentation allows each region to perform its specific function - terminal cores redirect leakage flux radially to reduce torque fluctuations, while the outer peripheral core concentrates magnetic flux. The modular segmented structure achieves torque stability without requiring overly complex integrated designs.
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 enhances average torque by stabilizing torque fluctuations and simplifying manufacturing by reducing the need for precise alignment of core pieces, while maintaining high magnetic flux concentration.
Implementation Method 1
outer peripheral core that is a magnetic material is attached to the intermediate portions in a longitudinal direction of the permanent magnets. Therefore, magnetic flux is concentrated on the intermediate portions in a longitudinal direction of an outer peripheral surface of the rotor
Implementation Method 2
maximum magnetic permeability of the terminal cores is equal to or less than maximum magnetic permeability of the outer peripheral core
Data Source
AI summary
A rotor extends towards the central axis of an electric motor rotation and is rotatably supported about the central axis of rotation. The rotor includes: permanent magnets arranged in its outer peripheral portion wherein N-poles and S-poles are alternately formed in the circumferential toward the rotor in the outer peripheral portion of the rotor, the N-poles and the S-poles being magnetic poles extending parallel toward the central axis of rotation; an outer peripheral core located facing the permanent magnet outer peripheral surfaces intermediate portions, the same portions excluding both end portions toward the central axis of rotation; and two terminal cores located at each end of the rotor toward the central axis of rotation. The outer peripheral core and the terminal cores are made of a magnetic material, and the maximum magnetic permeability of the terminal cores is equal to or less than that of the outer peripheral core.