Stator Insulating Sheet Extension for Axial Displacement Control
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Solution Overview
Problem
In stators for rotating electric machines, insulating sheets inserted in slots can be axially displaced due to frictional forces, leading to reduced insulating performance and increased void spaces, which complicates the manufacturing process and may damage substrates.
Innovation Solution
The stator configuration includes insulating sheets with a curable and foamable resin layer on the outer surface, featuring an extension portion outside the slot that faces the axial end face of the stator core, preventing axial displacement and eliminating the need for chamfering corner edges, while an inner resin layer is excluded from the extension portion to facilitate coil insertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulating sheets are inserted in slots to electrically insulate the stator coil from the stator core, then insulating performance is improved, but the insulating sheets may be axially displaced by frictional force during coil insertion, lowering insulating performance
Solution Approach 1:
The insulating sheet is extended in the axial direction beyond the slot opening, creating an extension portion that protrudes from the stator core. This dimensional extension allows the insulating sheet to be positioned and fixed axially, preventing displacement during coil insertion while maintaining electrical insulation between the stator coil and stator core.
Solution Approach 2:
The insulating sheet is pre-positioned in the slot with its extension portion protruding axially before the stator coil is inserted. This preliminary positioning ensures that when the coil is inserted, the insulating sheet is already in place to prevent axial displacement, rather than attempting to secure it after insertion.
2Productivity
If insulating sheets are tightly fitted in slots to minimize void spaces and improve space factor, then space utilization is improved, but insulating sheets become more susceptible to axial displacement during coil insertion
Solution Approach 1:
By extending the insulating sheet axially beyond the slot opening, the invention creates an additional dimension for positioning and stabilization. This extension portion allows the sheet to be securely positioned without increasing its radial or circumferential dimensions, thus maintaining high space factor while preventing axial displacement.
Solution Approach 2:
The insulating sheet is functionally segmented into two portions: a main body portion fitted within the slot for electrical insulation and space factor optimization, and an extension portion protruding axially for positioning and stabilization. This segmentation allows each portion to fulfill its specific function without compromising the other.
3Stability of the object's composition
If insulating sheets are extended axially to prevent displacement, then axial position stability is improved, but manufacturing complexity increases due to chamfering requirements
Solution Approach 1:
The extension portion is created by extending the insulating sheet in the axial direction, utilizing the existing axial dimension rather than requiring additional machining operations. This approach achieves positional stability through geometric extension rather than complex manufacturing processes like chamfering.
Solution Approach 2:
The invention extracts the chamfering operation from the manufacturing process by designing the insulating sheet with an extension portion that naturally prevents displacement. This eliminates the need for additional machining steps, simplifying manufacturing while maintaining axial position stability.
4Reliability
If resin layer is provided on the entire outer surface of the substrate including extension portion, then insulating performance is improved, but coil insertion becomes difficult due to friction
Solution Approach 1:
The resin layer is selectively applied only to the main body portion of the insulating sheet that is inserted within the slot, while the extension portion remains free of resin coating. This local differentiation ensures electrical insulation where needed (within the slot) while maintaining low friction for coil insertion (at the extension portion).
Solution Approach 2:
The insulating sheet is functionally segmented regarding resin application: the main body portion receives resin coating for electrical insulation, while the extension portion remains uncoated to facilitate smooth coil insertion. This segmentation allows each region to have the properties it needs for its specific function.
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 configuration effectively suppresses axial displacement of insulating sheets, maintains insulation integrity, simplifies manufacturing by omitting chamfering processes, and ensures reliable fixation of the stator coil, enhancing the overall performance and efficiency of the stator.
Implementation Method 1
The resin layer is formed of a curable and foamable resin that is foamed and cured by external stimulation
Implementation Method 2
The resin layer is formed of a curable and foamable resin that is foamed and cured by external stimulation
Data Source
AI summary
A stator includes an annular stator core having slots formed therein, a stator coil received in the slots, and insulating sheets each being interposed, in a corresponding one of the slots, between the stator coil and an interior wall surface of the stator core defining the corresponding slot. Each of the insulating sheets includes a sheet-like substrate and a resin layer provided on an outer surface of the substrate. The resin layer is formed of a curable and foamable resin that is foamed and cured by external stimulation. Each of the insulating sheets has an extension portion located outside the corresponding slot and extending nonparallel to an axial direction of the stator core so as to face an axial end face of the stator core. In each of the insulating sheets, the resin layer is provided, on the outer surface of the substrate, in a region including the extension portion.