Elliptical Stator Coil Ends for Rotating Machine Cooling
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Solution Overview
Problem
The challenge is to enhance the cooling performance of a stator for a rotating electrical machine while reducing its size, as existing designs face difficulties in cooling when miniaturized for installation in narrow spaces, such as those found in automobiles.
Innovation Solution
The stator design features an elliptical shape for its coil ends around the center axis of the stator iron core, with a welding process that varies the positions of welding electrodes to create an elliptical welded side coil end, increasing the contact area with refrigerants for improved cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the stator is reduced in size for installation in narrow spaces, then the installation space requirement is improved, but the cooling performance deteriorates
Solution Approach 1:
The patent applies asymmetry by changing the coil end shape from circular to elliptical. The elliptical shape creates an asymmetric geometry with a larger surface area relative to its volume, which enhances the contact area with refrigerants for improved cooling performance while maintaining a compact overall size for installation in narrow spaces.
Solution Approach 2:
The patent utilizes dimensionality change by transitioning from a circular cross-section to an elliptical cross-section. This dimensional transformation allows the coil end to achieve a more favorable surface-area-to-volume ratio, improving heat dissipation capability without proportionally increasing the overall volume, thus enabling better cooling performance in a compact stator design.
2Adaptability or versatility
If the coil ends height is lowered to secure gap for attachment sections, then the installation adaptability is improved, but the cooling performance deteriorates
Solution Approach 1:
The elliptical shape provides asymmetry that allows optimized heat dissipation surfaces while maintaining reduced height. The ellipse can be oriented with its major axis perpendicular to the height direction, providing sufficient cooling surface area even when the overall height is constrained for installation adaptability in narrow spaces with attachment sections.
Solution Approach 2:
The patent applies local quality by concentrating heat dissipation functionality in specific regions of the coil end. The elliptical shape creates localized areas with enhanced surface area for heat transfer, ensuring that cooling performance is maintained even when the overall coil end height is reduced to accommodate attachment sections.
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 effectively enhances the cooling performance of the stator, maintaining reliability and durability even in a smaller size, allowing for higher power output and efficient heat dissipation.
Implementation Method 1
a welding step in which a plurality of segment conductors which are inserted through the slots of the stator iron core and constitute the stator coil is electrically welded to one another
Implementation Method 2
the coil end section being divided into a plurality of areas and the positions of welding electrodes being varied in each of such areas at the welding step... the contact area with refrigerants for improved cooling efficiency
Data Source
AI summary
A stator for a rotating electrical machine includes a stator coil and a stator iron core having slots into which the stator coil is mounted, wherein a coil end of the stator coil is elliptical in shape around a center axis of the stator iron core.