Rotor Yoke Segmentation for Magnet Cooling and Magnetic Resistance
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Solution Overview
Problem
Rotating electric machine rotors face challenges in effectively cooling magnets due to high magnetic flux density regions that increase magnetic resistance when internal cavities interrupt these areas, leading to inefficiencies and heat management issues.
Innovation Solution
A rotor design featuring a rotor yoke with annular magnetic steel sheets subjected to rotary lamination, including first and second internal cavities, and strategically positioned through-holes to facilitate refrigerant circulation and minimize magnetic resistance, allowing for efficient cooling of magnets while maintaining structural strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If internal cavities are provided in the rotor yoke to cool magnets, then cooling capability is improved, but magnetic resistance increases due to interruption of magnetic flux density regions
Solution Approach 1:
The internal cavity is segmented into multiple regions (first internal cavity region, second internal cavity region, third internal cavity region) with different functions. The first region provides cooling, the second region maintains magnetic flux continuity, and the third region facilitates refrigerant circulation. This segmentation allows the cavity to simultaneously achieve cooling capability while minimizing magnetic resistance by preserving continuous magnetic flux paths through the second internal cavity region.
2Temperature
If rotary lamination is applied to create spiral internal cavities, then cooling circulation is improved, but manufacturing complexity increases
Solution Approach 1:
The magnetic steel sheet is divided into multiple regions (first, second, third through-holes and corresponding internal cavity regions) that can be independently formed and then assembled. This segmentation allows each region to be optimized for its specific function while simplifying the overall manufacturing process compared to creating complex spiral cavities through rotary lamination.
Solution Approach 2:
The invention transitions from the conventional rotary lamination approach (which creates spiral cavities through rotational stacking) to a planar segmentation approach where multiple through-holes and cavity regions are formed within individual magnetic steel sheets or simple stacks. This dimensional simplification maintains the cooling circulation function while dramatically reducing manufacturing complexity.
3Weight of moving object
If internal cavities are created to decrease inertial mass, then rotor weight is reduced, but structural strength decreases
Solution Approach 1:
The rotor yoke is segmented into multiple magnetic steel sheets with strategically positioned through-holes and internal cavity regions. This segmentation creates a lightweight structure with reduced inertial mass while the distributed cavity design and strategic placement of magnetic steel regions maintain the overall structural strength and rigidity of the rotor.
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 design effectively suppresses magnetic resistance and enhances cooling capabilities, improving the efficiency and heat management of rotating electric machines by ensuring appropriate refrigerant circulation and maintaining the rotor's strength.
Implementation Method 1
a plurality of first internal cavities formed in the axial direction on an inner circumference side of the magnet slots and a plurality of second internal cavities provided in the axial direction on an outer circumferential side of the first internal cavities
Data Source
AI summary
A rotor for a rotating electric machine is disclosed which includes a rotor yoke including annular magnetic steel sheets stacked in an axial direction having magnet slots into which magnets inserted, Each magnetic steel sheet includes first through-holes to form the first internal cavities; second through-holes, each having a shape fit for each second internal cavity and configured to form part of one of the second internal cavities; and third through-holes, each having a shape for communication between one of the first internal cavities and one of the second internal cavities and to form, with one of the second through-holes, part of the one of the second internal cavities.