Axial Flux Motor Stator Cooling With Inner Annular Flow Channels

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Solution Overview

Problem

Existing axial flux motor cooling structures face inefficiencies in heat exchange due to uneven cooling medium distribution and processing difficulties that affect the motor's strength and supporting ability.

Innovation Solution

A stator cooling structure with radially arranged inner annular flow channels and oil injection holes ensures even distribution of the cooling medium, covering all iron core windings and gaps, while minimizing processing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a channel is opened at the bottom portion of the housing, then the cooling medium can be introduced to exchange heat with heating elements, but the cooling medium does not directly contact with the iron core windings causing poor heat exchange and the processing difficulty affects supporting ability and strength

Engineering Contradiction:
Improvecooling effectVSAvoidsupporting ability
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The cooling structure is segmented into multiple independent flow channels (first flow channel, second flow channel, third flow channel) that are radially arranged within the housing. Each channel serves a specific cooling zone, allowing the cooling medium to directly contact different portions of the iron core windings. This segmentation enables effective heat exchange without requiring a single complex bottom channel that would compromise structural strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cooling channels are arranged in the radial dimension rather than requiring a bottom channel configuration. The first flow channel extends from the inner peripheral plate toward the outer peripheral plate, while the second and third flow channels are circumferentially offset. This radial arrangement allows direct contact with iron core windings in multiple dimensions without compromising the bottom plate's supporting ability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Temperature

If the cooling medium is introduced into the housing to exchange heat with iron core windings, then cooling is achieved, but the cooling medium flows unevenly in the gaps between iron core windings and housing resulting in suboptimal cooling effect

Engineering Contradiction:
Improvecooling effectVSAvoidflow distribution uniformity
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

Different flow channels are designed with specific local functions to address uneven flow distribution. The first flow channel is positioned to cool the inner peripheral region, the second flow channel addresses the intermediate region, and the third flow channel covers the outer peripheral region. Each channel's geometry and positioning are optimized for its specific zone, ensuring uniform cooling across all gaps between iron core windings and the housing.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Instead of relying on a single flow channel that may not adequately cover all gaps, the design implements multiple flow channels that collectively provide excessive cooling coverage. This ensures that even if one channel's flow is insufficient, other channels compensate, achieving uniform cooling across all critical gaps through redundant partial actions.

Inventive Principle:
Principle #16Partial or excessive action

3Temperature

If multiple flow channels are arranged radially inside the flow areas, then the cooling medium flows evenly through all gaps improving cooling effect, but the processing complexity increases

Engineering Contradiction:
Improvecooling effectVSAvoidprocessing complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

Multiple flow channels are merged into a single integrated cooling structure that is formed as one piece with the housing. The first, second, and third flow channels are all formed within the same housing component, sharing common walls and structural support. This merging reduces the number of separate parts and assembly steps, lowering processing complexity while maintaining the benefits of multiple radial channels for even cooling.

Inventive Principle:
Principle #5Merging (Combining)

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 lowers the temperature of iron core and coil windings, enhancing motor operation reliability, efficiency, and peak power while maintaining structural integrity.

Implementation Method 1

the cooling medium may flow evenly between the flow areas and the inner annular flow channels through circumferentially arranged oil injection holes, which makes flow direction of the cooling medium cover all of the iron core windings, and the cooling medium uniformly pass through gaps between the iron core windings and gaps between the iron core windings and the housing, thereby improving the cooling effect

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP4607758A1Axial flux motor stator cooling structure and axial flux motor
Publication Date: 2025.08.27 SHANGHAI PANGOOD POWER TECH CO LTD
  • EP4607758A1 patent drawingFigure 1~2
  • EP4607758A1 patent drawingFigure 3~4
  • EP4607758A1 patent drawingFigure 5~6

AI summary

An axial flux motor stator cooling structure and an axial flux motor are provided. The axial flux motor stator cooling structure includes a housing, multiple iron core windings, and an inner annular reversing flow channel assembly; the housing has an annular accommodating cavity and a bushing hole; the plurality of iron core windings are mounted in the annular accommodating cavity and form at least two flow areas with the housing; and the inner annular reversing flow channel assembly is mounted in the bushing hole, and includes at least one inner annular flow channel that is communicated with two different flow areas. It is ensured that a cooling medium can pass through each gap uniformly, so that the cooling medium can completely soak the iron core windings, thereby improving the cooling performance.