Stator Core Teeth With Integral Cooling Ducts for Hair-Pin Motors

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Solution Overview

Problem

Air-cooled motors with hair-pin type designs suffer from inadequate cooling, leading to insulation breakdown due to excessive temperatures and high core losses, despite existing cooling systems.

Innovation Solution

Incorporation of triangular shaped holes or cooling ducts in the roots of stator teeth to enhance airflow for improved heat dissipation, reducing material weight and core losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If traditional hair-pin type stator design is used, then manufacturing simplicity is maintained, but cooling efficiency is insufficient leading to excessive temperatures

Engineering Contradiction:

Improvecooling efficiencyVSAvoidstator core structure

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The stator core is segmented into multiple teeth with individual cooling ducts in each tooth. Each cooling duct is formed as a separate triangular hole running through the tooth, allowing independent cooling channels that can be optimized for airflow while maintaining structural integrity of the overall stator core.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The stator core incorporates porous-like cooling ducts within the teeth structure. These triangular holes create a network of cooling passages throughout the stator core, enabling effective heat dissipation while maintaining the solid structural framework needed for magnetic flux conduction.

Inventive Principle:

Principle #31Porous materials

2Temperature

If cooling ducts are added to the stator core, then cooling efficiency improves, but manufacturing complexity increases

Engineering Contradiction:

Improvecooling efficiencyVSAvoidmanufacturing process

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The cooling ducts are formed as integral parts of the stator core during the initial manufacturing process. The triangular holes are created within the tooth structure before final assembly, eliminating the need for separate cooling duct installation steps and reducing overall manufacturing complexity despite the added cooling functionality.

Inventive Principle:

Principle #10Preliminary action

3Weight of stationary object

If material is removed to create cooling ducts, then weight is reduced, but structural strength may be compromised

Engineering Contradiction:

Improvestator core weightVSAvoidtooth structural integrity

Core Design Contradiction:

Weight of stationary objectVSStrength

Solution Approach 1:

The cooling ducts are designed with asymmetric triangular cross-sections that are strategically positioned within the teeth. The triangular shape allows for optimal material removal for cooling while maintaining structural strength in critical areas, as the geometry can be optimized to preserve load-bearing paths while creating effective cooling passages.

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

Enhances cooling efficiency, reduces material weight, and minimizes core losses by providing additional heat rejection pathways through the triangular shaped channels in the stator core.

Implementation Method 1

the one or more triangular holes are receptive of a cooling airflow

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentEP3790167B1Motor stator core design with integral cooling duct within teeth

Publication Date: 2026.04.15 HAMILTON SUNDSTRAND CORP

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AI summary

A stator core is provided and includes laminations (110) disposed in a laminated arrangement to form a stator core body (120) having an axial length extending in a lamination dimension. The stator core body includes an annular portion (121) extending along the axial length and teeth (122) extending radially from the annular portion and along the axial length. Each tooth has a trapezoidal shape (123) and is formed to define one or more triangular holes (124) running along the axial length.