Rotor Core Cavity Layout for Lightweight High-Torque Motors
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Solution Overview
Problem
Permanent magnet-type rotary electric machines face challenges in achieving high torque and output in a compact, lightweight design for applications like electric vehicles, where space is limited and weight reduction is crucial.
Innovation Solution
The design incorporates a rotor core with strategically placed permanent magnets and cavity holes, optimized to maximize the size of cavity holes while maintaining structural strength, which reduces the rotor's weight and enhances magnetic flux management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the rotor core is designed with larger cavity holes to reduce weight, then the weight of the rotor is reduced, but the structural strength may be compromised
Solution Approach 1:
The rotor core is segmented into multiple magnetic poles with cavity holes strategically positioned between them. This segmentation allows the cavity holes to remove non-essential material for weight reduction while the magnetic pole structures maintain the overall structural integrity and strength of the rotor core.
Solution Approach 2:
The cavity holes are positioned in specific locations between magnetic poles where material removal has minimal impact on structural strength. The design optimizes the size and position of cavity holes to achieve maximum weight reduction while maintaining adequate structural strength in critical areas.
2Power
If permanent magnets are arranged to open symmetrically towards outer and inner circumferential surfaces, then reluctance torque is enhanced in addition to magnet torque, but the device complexity increases
Solution Approach 1:
Each magnetic pole is segmented into two permanent magnets positioned symmetrically - one opening towards the outer circumferential surface and another towards the inner circumferential surface. This segmentation enables the generation of both magnet torque and reluctance torque, enhancing overall power output while maintaining a systematic structure.
Solution Approach 2:
The permanent magnets within each magnetic pole are arranged asymmetrically with respect to the rotor core - one magnet opens outward while the other opens inward. This asymmetric arrangement within each pole creates the dual-torque mechanism that enhances power output.
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 allows for a lightweight rotary electric machine with increased torque and output, achieving a balance between compactness and efficiency.
Implementation Method 1
a rotary electric machine includes a stator including a stator core and an armature coil and a rotor including a shaft rotatable around a central axis, a rotor core coaxially fixed to the shaft and including a plurality of magnetic poles arranged along a circumferential direction, and a plurality of permanent magnets embedded in the rotor core and disposed in the plurality of magnetic poles respectively
Implementation Method 2
a plurality of permanent magnets embedded in the rotor core and disposed in the plurality of magnetic poles respectively
Implementation Method 3
a plurality of cavity holes each provided between each respective adjacent pair of magnetic poles to oppose the embedding holes, respectively, with a gap therebetween
Data Source
AI summary
According to one embodiment, a rotor core satisfies a relationship: W2/W1≤(A1+A2)/A1. Where, A1 represents an area of a region defined by a polar central axis, an outer circumferential surface of the rotor core and a first imaginary linear line extending on an outer circumferential-side long edge of an embedding hole, A2 represents an area of a region defined by the polar central axis, a q-axis, the outer circumferential surface of the rotor core, a second imaginary linear line extending on an inner circumferential-side long edge of the embedding hole, a third imaginary linear line extending on a first edge of the cavity hole, W1 represents a half-width of a first bridge portion, and W2 represents a half-width of the second bridge portion.