Stator Coil Radial Gap Design for Heat Dissipation

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Solution Overview

Problem

Stators for electric rotating machines face challenges in heat dissipation, leading to increased temperature and electric resistance of stator coils due to inadequate heat transmission from in-slot portions to the stator core, which can result in physical damage from Lorentz force-induced vibrations.

Innovation Solution

The stator design features in-slot portions with radially-facing surfaces oriented non-parallel to each other, creating gaps for improved heat dissipation and vibration absorption, using an impregnating material with higher thermal conductivity to enhance heat transfer and stability, and varying gap sizes to distribute heat evenly across the stator core.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If in-slot portions are arranged close to each other to increase packing factor, then space utilization is improved, but heat transmission to stator core deteriorates

Engineering Contradiction:

Improvepacking factorVSAvoidheat dissipation

Core Design Contradiction:

Quantity of substanceVSTemperature

Solution Approach 1:

The in-slot portions are segmented such that adjacent portions have radially-facing surfaces extending in non-parallel directions, creating intentional gaps between them. This segmentation maintains high packing factor while enabling heat transmission pathways to the stator core through the gaps.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Adjacent in-slot portions are designed with asymmetric orientations where their radially-facing surfaces extend in non-parallel directions. This asymmetric arrangement creates gaps that facilitate heat dissipation while maintaining efficient space utilization within the slot.

Inventive Principle:

Principle #4Asymmetry

2Ease of manufacture

If in-slot portions are placed in close contact to maximize space usage, then manufacturing simplicity is improved, but heat transmission capability deteriorates

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidheat transmission

Core Design Contradiction:

Ease of manufactureVSTemperature

Solution Approach 1:

The in-slot portions are manufactured with asymmetric radial orientations, creating gaps without requiring complex assembly processes. This asymmetric design is integrated into the manufacturing of the portions themselves, maintaining ease of manufacture while improving heat transmission.

Inventive Principle:

Principle #4Asymmetry

3Temperature

If gaps are created between in-slot portions for heat dissipation, then temperature control is improved, but vibration stability deteriorates

Engineering Contradiction:

Improvetemperature controlVSAvoidvibration stability

Core Design Contradiction:

TemperatureVSStability of the object's composition

Solution Approach 1:

The gaps between in-slot portions are designed with specific local characteristics - they are positioned and sized to optimize heat dissipation while the non-parallel orientation of radially-facing surfaces provides mechanical stability against Lorentz force-induced vibrations. Different regions of the in-slot portions have different functional qualities.

Inventive Principle:

Principle #3Local quality

4Manufacturing precision

If uniform gaps are maintained between in-slot portions, then manufacturing precision is improved, but heat dissipation uniformity deteriorates

Engineering Contradiction:

Improvegap uniformityVSAvoidheat dissipation uniformity

Core Design Contradiction:

Manufacturing precisionVSTemperature

Solution Approach 1:

Instead of uniform gaps, the invention employs asymmetric gap arrangements where adjacent in-slot portions have radially-facing surfaces extending in non-parallel directions. This creates varied gap sizes and orientations that promote more uniform heat dissipation across different regions of the stator core, while the manufacturing precision is maintained through controlled asymmetric geometry.

Inventive Principle:

Principle #4Asymmetry

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 minimizes temperature rise and electric resistance in stator coils, prevents physical damage from vibrations, and ensures uniform heat dissipation, thereby enhancing the performance and reliability of electric rotating machines.

Implementation Method 1

using an impregnating material with higher thermal conductivity to enhance heat transfer

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS8421295B2Stator for electric rotating machine with enhanced cooling ability

Publication Date: 2013.04.16 DENSO CORP

AI summary

A stator for an electric rotating machine is provided which is equipped with a stator coil. The stator coil has a plurality of in-slot portions arrayed within each of slots formed in a stator core in a radial direction of the stator core. Adjacent two of the in-slot portions disposed in each of the slots have radially-facing surfaces which extend in non-parallel to one another at least one of ends of the in-slot portions. The non-parallel orientation of the radially-facing surfaces avoids close contact between entire areas thereof when the in-slot portions move undesirably within the slot in the radial direction of the stator core. In other words, a gap is kept between the radially-facing surfaces and serves as a radiator to dissipate heat, as generated in the in-slot portions.