Segment-Conductor Stator Geometry for Cooling and Coil Fixation
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Solution Overview
Problem
Existing stator designs face challenges in balancing cooling efficiency, output, and fixing force of coils due to the arc-shaped corner portions of segment conductors, which either reduce cross-sectional area or increase pressure loss in coolant flow channels.
Innovation Solution
A stator design with segment conductors featuring flat and curved surfaces, along with foaming adhesive sheets, ensures a stable fixing force while maintaining output and reducing pressure loss by optimizing coolant flow channel dimensions and adhesive contact areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the gap between the segment conductor and the slot is increased to increase cooling efficiency, then the cooling efficiency is improved, but the cross-sectional area of the coil is reduced and output weakens
Solution Approach 1:
The segment conductor is designed with different surface characteristics at different locations: flat surfaces at corners for maintaining cross-sectional area and arc-shaped surfaces at curved portions for reducing coolant pressure loss. This local differentiation allows the gap to be increased for cooling without compromising overall output.
2Power
If the cross-sectional area of the segment conductor is increased to increase the output of the coil, then the coil output is improved, but the gap becomes smaller which increases pressure loss in the coolant
Solution Approach 1:
Arc-shaped surfaces are provided at the curved portions of the segment conductor where they contact the slot. This local arc-shaped design reduces coolant pressure loss in the gap without requiring an increase in the overall cross-sectional area of the segment conductor, thus maintaining coil output while improving cooling efficiency.
3Loss of energy
If the contact area between the segment conductor and the slot is reduced, then the pressure loss in coolant is reduced, but the fixing force weakens causing position shift and vibrations
Solution Approach 1:
The segment conductor has flat surfaces at corner portions for maintaining fixing force and arc-shaped surfaces at curved portions for reducing pressure loss. This local differentiation allows the contact area to be optimized for cooling without compromising fixing force.
Solution Approach 2:
The segment conductor features asymmetric surface geometry with flat surfaces at some corners and arc-shaped surfaces at curved portions. This asymmetric design allows different regions to serve different functions: fixing and cooling optimization.
4Ease of operation
If the corner portion of the segment conductor has an arc shape, then the coolant flow is improved, but the cross-sectional area of the coil is reduced
Solution Approach 1:
Arc-shaped surfaces are provided only at the curved portions of the segment conductor where they contact the slot, while corner portions maintain flat surfaces. This local arc-shaped design improves coolant flow without significantly reducing the overall cross-sectional area of the coil.
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 stabilizes coil fixation, enhances output, and reduces coolant pressure loss by increasing coolant flow channel area and adhesive contact, thereby improving overall stator performance.
Implementation Method 1
the foaming adhesive sheet has a foaming adhesive layer that foams and expands due to heating
Implementation Method 2
the coolant such as oil or the like flows through a gap (coolant flow channel) formed between an outer circumferential surface of the segment conductor and an inner circumferential surface of the slot
Data Source
AI summary
A stator includes a cylindrical stator core having a plurality of slots, and a plurality of coils having segment conductors inserted through the plurality of slots and extending in axial direction, a coolant flow channel through which coolant flows is formed between outer circumferential surface of the segment conductor and inner circumferential surface of the slot, the outer circumferential surface of the segment conductor includes first flat surface facing radial direction, second flat surface facing circumferential direction, and a corner portion curved surface connecting the first flat surface and the second flat surface, the corner portion curved surface includes first curved surface continuous with the first flat surface and second curved surface continuous with the second flat surface, and when seen in cross-sectional view perpendicular to the axial direction, radius of curvature of the first curved surface is greater than radius of curvature of the second curved surface.