Waveguide Stator Cooling With Simplified End Sealing

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Solution Overview

Problem

Existing cooling systems for motor stators in new energy vehicles suffer from inefficient indirect cooling paths and complex sealing structures, particularly in stators with waveguides, leading to high thermal resistance and increased manufacturing costs.

Innovation Solution

A direct cooling system for motor stators with waveguides, featuring a coolant inlet and outlet on opposite ends, forming a sealing chamber with the motor housing, and utilizing a simplified sealing element or integrated design to reduce thermal resistance and manufacturing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If indirect cooling through water jacket channels is used, then the cooling system is simple to implement, but the cooling path is long and cooling efficiency is poor

Engineering Contradiction:
Improvecooling system implementation simplicityVSAvoidcooling efficiency
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The patent uses the stator slots as an intermediary structure to deliver coolant directly to the conductor bars. The slots serve as both structural support for the windings and as coolant channels, eliminating the need for separate water jackets while achieving direct cooling of the heat-generating conductors.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention transitions from external circumferential cooling (water jacket around the stator) to internal axial cooling (coolant flowing through slots from one end to the other). This dimensional change allows the coolant to reach the conductors directly at their location rather than cooling the outer housing.

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

2Temperature

If direct cooling of the stator waveguide is used, then cooling requirements are met, but sealing between waveguide and housing is difficult and structure becomes complex

Engineering Contradiction:
Improvecooling effectVSAvoidsealing structure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The stator slots serve multiple functions simultaneously: they provide mechanical support for the conductor bars, enable coolant flow for direct cooling, and create sealing chambers when combined with the sealing element. This multi-functionality eliminates the need for separate sealing structures.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention extracts the sealing function from a separate complex sealing structure and integrates it into the existing stator slot geometry. By using the slot walls and a simple sealing element, the sealing function is achieved without adding structural complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If separate oil inlet and outlet chambers are used, then cooling flow is controlled, but the structure becomes complex and costs increase

Engineering Contradiction:
Improvecooling flow controlVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the oil inlet chamber and oil outlet chamber into a single continuous cooling channel formed by the stator slots. The coolant flows continuously from the inlet at one end through the slots to the outlet at the other end, eliminating the need for separate chambers while maintaining controlled cooling flow.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of manufacture

If the cooling path runs through solid conductor - insulation - stator core - aluminum housing - coolant, then indirect cooling is achieved, but the long path reduces cooling efficiency

Engineering Contradiction:
Improveindirect cooling implementationVSAvoidcooling path length
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The stator slots act as an intermediary coolant delivery system that brings the coolant directly to the conductor bars. This eliminates the long indirect path through insulation and housing by creating a direct thermal coupling between the coolant and the heat-generating conductors via the slot geometry.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The direct cooling system significantly shortens the cooling path, enhances sealing effectiveness, and reduces manufacturing costs by simplifying the assembly process, thereby improving thermal efficiency and power output.

Implementation Method 1

The cooling path runs directly from the coolant to the inner surface of the waveguide, which significantly shortens the cooling path

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a cooling device (3), comprising a first cooling channel (31) arranged in the waveguide (23) of the conductor element of the winding structure (2)

Methodology Applied
Scientific EffectForced convection: Forced Convection

Data Source

PatentEP4693834A1Stator and motor
Publication Date: 2026.02.11 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP4693834A1 patent drawingFigure 1
  • EP4693834A1 patent drawingFigure 2
  • EP4693834A1 patent drawingFigure 3

AI summary

The present invention relates to a stator for a motor, comprising a stator core, a winding structure, and a cooling device, wherein the stator core has slots for receiving the winding structure to be inserted, and the winding structure projects from the slots of the stator core at both axial end faces, forming a first end and a second end of the winding structure, wherein the conductor element of the winding structure is a waveguide in which a first cooling channel of the cooling device is arranged, a coolant inlet of the first cooling channel is located at the first end, and a coolant outlet of the first cooling channel is located at the second end, wherein the cooling device has a sealing element which, together with the motor housing surrounding the stator on the side of the first end, forms a sealing chamber enclosing the coolant inlet. The invention further relates to a motor with such a stator.