Stator Insulating Coat Thickness at Indentations
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Solution Overview
Problem
Existing stators for rotating electric machines face challenges in maintaining sufficient electrical insulation and cooling between protruding portions of electric conductor segments due to reduced insulating coat thickness at indentations, which can lower insulating performance and hinder reliable electrical insulation between in-slot portions.
Innovation Solution
The stator design features electric conductor segments with indentations on their protruding portions, where the insulating coat thickness is maintained equal to that of the in-slot portions, and the coating material has a lower Young's modulus and higher yield point than the metal material, allowing for sufficient clearance and improved insulation without compromising cooling, achieved through a manufacturing process that forms indentations by pressing with a load higher than the metal's yield point but not exceeding the coating material's yield point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If indentations are formed in the side faces of the protruding portions of the electric conductor segments by pressing, then a sufficient clearance can be secured between intersecting protruding portions, improving electrical insulation and cooling, but the thickness of the insulating coats covering the outer surfaces of the electric conductor segments is reduced at the indentations, lowering the insulating performance
Solution Approach 1:
The patent changes the physical parameters of the materials involved by selecting a coating material with a lower Young's modulus and higher yield point than the metal material. This parameter difference allows the pressing process to deform the metal substrate into indentations while the coating material maintains its integrity and thickness, thus improving clearance for insulation without compromising the insulating coat's protective function.
Solution Approach 2:
The patent employs a composite structure consisting of the metal electric conductor segment substrate and the insulating coating layer. By carefully selecting materials with complementary properties (metal with higher yield point for structural deformation, coating with lower Young's modulus for flexibility and thickness retention), the composite structure enables the formation of indentations that provide clearance while preserving the insulating coat's thickness and insulating performance.
2Temperature
If the thickness of the insulating coats covering the in-slot portions of the electric conductor segments is set to be smaller, then heat generated by the in-slot portions can be transmitted more effectively to the stator core, but it may be difficult to reliably ensure electrical insulation between the in-slot portions
Solution Approach 1:
The patent applies different insulating coat thicknesses to different locations of the electric conductor segments. The in-slot portions have thinner insulating coats to facilitate heat transmission to the stator core, while the protruding portions maintain sufficient insulating coat thickness (preserved at indentations) to ensure electrical insulation. This local differentiation of insulating coat quality resolves the contradiction between heat dissipation and insulation requirements.
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 ensures reliable electrical insulation and effective cooling by maintaining insulating coat thickness, preventing performance degradation at indentations, and facilitating efficient air flow for cooling, while reducing manufacturing costs by optimizing the pressing load.
Implementation Method 1
the pressing load is set so as to be higher than the yield point of the metal material but not higher than the yield point of the coating material
Implementation Method 2
the coating material has a lower Young's modulus and a higher yield point than the metal material
Implementation Method 3
improving both electrical insulation between the protruding portions and cooling of the protruding portions via cooling air
Data Source
AI summary
A stator includes a hollow cylindrical stator core and a stator coil formed of a plurality of electric conductor segments. Each of the electric conductor segments includes, at least, an in-slot portion received in a corresponding slot of the stator core and a protruding portion that protrudes from the in-slot portion outside of the corresponding slot. Each of the electric conductor segments also has an insulating coat covering its outer surface. For each intersecting pair of the protruding portions of the electric conductor segments, at least one of the two protruding portions of the intersecting pair has an indentation formed in a side face thereof radially facing the other protruding portion at the intersection of the two protruding portions. Further, a thickness of the insulating coats at the indentations is substantially equal to a thickness of the insulating coats at the in-slot portions of the electric conductor segments.