Internal Stator Cooling Assembly with Biasing Segments
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Solution Overview
Problem
Cooling internal stator electric machines is challenging as convection cooling is hindered by the rotor surrounding the stator, requiring effective heat extraction methods from within the stator.
Innovation Solution
A cooling assembly with a cylindrical support structure and biasing assemblies is inserted inside the stator, featuring longitudinal channels and cooling segments with inlet and outlet channels, allowing for continuous fluid flow and secure mounting to the stator's inner surface using biasing elements to enhance heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If convection cooling is used for external stators, then cooling effectiveness is improved, but this method cannot be applied to internal stators surrounded by rotors
Solution Approach 1:
The cooling assembly is divided into multiple independent cooling segments that can be individually installed within the internal stator. Each segment contains cooling channels and can be independently biased against the stator inner surface, allowing the cooling system to adapt to the constrained internal stator geometry while maintaining effective heat removal
Solution Approach 2:
The invention transitions from external convection cooling (three-dimensional surface cooling) to internal contact cooling by placing cooling segments in direct thermal contact with the stator's inner surface. This dimensional shift allows heat extraction from within the stator where conventional convection cannot reach
2Temperature
If cooling segments are firmly fixed to extract heat efficiently, then heat transfer effectiveness is improved, but thermal dilatation and contraction cannot be accommodated
Solution Approach 1:
The biasing assembly provides a dynamic, adjustable pressing force that maintains optimal thermal contact between cooling segments and the stator inner surface. The spring mechanism automatically adjusts to thermal dilatation and contraction, preserving heat transfer effectiveness while accommodating dimensional changes during operation
Solution Approach 2:
The biasing assembly is specifically designed to accommodate thermal expansion and contraction of the stator. The spring-loaded mechanism allows for dimensional changes while maintaining consistent pressing force, ensuring that thermal contact is preserved across varying temperature conditions
3Strength
If the entire cooling assembly is designed as a single unit, then structural integrity is improved, but replacement of defective segments requires complete disassembly
Solution Approach 1:
The cooling assembly is segmented into multiple independently replaceable units, each containing cooling channels and biasing mechanisms. This segmentation allows defective segments to be individually removed and replaced without disassembling the entire cooling system, significantly simplifying maintenance while maintaining overall structural integrity through the modular design
4Ease of repair
If cooling segments are made removable for maintenance, then ease of repair is improved, but secure mounting and heat transfer contact become difficult to maintain
Solution Approach 1:
The biasing assembly provides a dynamic, self-adjusting pressing force that maintains optimal thermal contact. The spring mechanism automatically compensates for wear, thermal expansion, and installation variations, ensuring stable heat transfer contact even though segments are designed to be removable for maintenance
Solution Approach 2:
The biasing assembly acts as an intermediary between the removable cooling segment and the stator inner surface. It provides the necessary pressing force to ensure thermal contact while allowing the segment to be independently installed or removed, bridging the requirement for both secure mounting and ease of repair
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 solution enables efficient heat transfer and removal from the stator, accommodating thermal dilatation and contraction, and allows for easy replacement of defective segments without disassembling the entire assembly, utilizing radial forces for assembly and potentially incorporating heat transfer grease for improved performance.
Implementation Method 1
each cooling element including a cooling channel provided with an inlet and an outlet
Implementation Method 2
at least two biasing assemblies respectively mounted to a longitudinal channel of the support structure so as to bias the outer surface of a cooling element to the inner surface of the internal stator
Implementation Method 3
Cooling internal stator machines is a challenge since one cannot rely on the air surrounding the stator as a cooling medium
Data Source
AI summary
A cooling assembly to be positioned inside an internal stator of an electric machine is described herein. The cooling assembly includes a plurality of cooling segments that may be so mounted to a support structure as to be biased towards an inner surface of the stator.