Liquid-Cooled Rotor Endring for Even Heat Extraction
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Solution Overview
Problem
Existing electric motors, particularly induction motors, face inefficiencies in thermal management due to uneven liquid distribution and suboptimal heat extraction, leading to increased operating temperatures and reduced performance.
Innovation Solution
The implementation of liquid cooling through optimized rotary heat sinks at the endrings of the rotor, utilizing centrifugal forces to distribute oil evenly and maximize heat extraction, with spacers and pin fins designed to enhance heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional liquid cooling is used in electric motors, then heat extraction is performed, but liquid distribution is uneven and heat extraction efficiency is suboptimal
Solution Approach 1:
The endring is segmented into multiple cooling zones with radially spaced cooling channels. Liquid coolant flows through multiple separate channels rather than a single channel, enabling even distribution of cooling liquid across different radial positions. This segmentation allows each channel to independently extract heat from specific zones, resolving the uneven liquid distribution problem and improving overall heat extraction efficiency.
Solution Approach 2:
Different regions of the endring are provided with cooling channels at different radial positions to match the local heat generation patterns. The cooling system is customized for each local area, with channels positioned to extract heat from high-temperature zones more intensively. This local quality approach ensures optimal heat extraction efficiency at each position while maintaining even liquid distribution throughout the structure.
2Temperature
If cooling channels are added to extract heat, then heat extraction improves, but device complexity increases
Solution Approach 1:
The cooling channels are integrated directly into the endring structure, merging the cooling system with the existing rotor component. The endring serves dual functions: maintaining rotor integrity and providing heat extraction pathways. This consolidation eliminates the need for separate cooling devices, reducing overall device complexity while maintaining effective heat extraction capability.
Solution Approach 2:
The endring is designed with multi-functionality, serving both as a structural component for rotor assembly and as a heat extraction device. The same component that provides mechanical support also contains the cooling channels, allowing it to perform multiple functions simultaneously. This universality reduces the number of separate components needed, simplifying the overall device structure while achieving effective cooling.
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 achieves a 140% increase in heat transfer coefficient and area product, reducing induction motor rotor temperatures, minimizing windage losses, and improving overall motor performance.
Implementation Method 1
utilizing centrifugal forces to distribute oil evenly
Implementation Method 2
enhance heat transfer efficiency
Data Source
AI summary
An electric motor comprises: a stator, a rotor comprising: a rotor shaft having a hollow interior and configured for rotation inside the stator about a rotor axis, the rotor shaft having at least one inlet into the hollow interior and at least one radial outlet from the hollow interior, and a rotor body and an endring at an end of the rotor body along the rotor axis; and a spacer forming an internal cavity to receive fluid from the hollow interior, the spacer having an outlet from the internal cavity.