Stator Insulating Sheet Layout for High-Density Coil Slots
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Solution Overview
Problem
In inner rotor type brushless motors, the high density coil layout is hindered by overlapping insulating sheets between adjacent coils, reducing the space factor and making it difficult to minimize motor size.
Innovation Solution
A stator configuration using two insulating sheets per coil, where one sheet wraps around the coil and the tooth, and the other does not overlap with adjacent coils, ensuring electrical insulation and maintaining a high space factor by preventing coil contact and allowing single-layer wrapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both ends of insulating sheets are laminated in two layers and bonded between adjacent coils, then electrical insulation between coils is secured, but the space factor decreases due to four layers of insulating sheets being present
Solution Approach 1:
The insulating sheet is divided into two distinct parts: a first insulating sheet that wraps the coil and provides insulation at the coil ends, and a second insulating sheet that covers only the tooth surface without extending between adjacent coils. This segmentation eliminates the overlapping four-layer structure while maintaining electrical insulation where needed.
Solution Approach 2:
The harmful overlapping portion of the insulating sheet is removed. The second insulating sheet is designed to cover only the tooth surface area, extracting the unnecessary extension that caused the four-layer overlap between adjacent coils, thereby reducing insulating material layers from four to two.
2Volume of moving object
If high density coil layout is implemented to reduce motor size, then occupancy of coil conductors in slot is improved, but overlapping insulating sheets between adjacent coils hinder the layout and reduce space factor
Solution Approach 1:
By segmenting the insulating sheet into two functional parts with different coverage areas, the design enables tighter coil packing. The first sheet provides necessary insulation at coil ends, while the second sheet insulates the tooth surface without creating overlapping layers between adjacent coils, thus improving the space factor for high-density coil layouts.
Data Source
AI summary
In a stator or a rotary electric machine, an insulating sheet spreads between two coils adjacent to each other in a circumferential direction in each slot. The insulating sheet covers the end in a third direction of the coil wound in a corresponding tooth, between end surfaces in an axial direction and between an inward-directed surface and an inclined surface in a radial direction. In the slot, an insulating sheet wrapping the adjacent coil is present, but the insulating sheet does not cover the end in a fourth direction of the coil wound around the corresponding tooth.