Motor Case Cooling Channel Segmentation for Compact Thermal Management

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Solution Overview

Problem

Existing motor designs face challenges in efficient cooling while minimizing the increase in motor volume, as annular rings for cooling can limit discharge points and increase the motor's size.

Innovation Solution

A motor design that includes a cooling medium channel and discharge portions in the motor case surface, allowing flexible pattern design for efficient cooling without significantly increasing space, with channels and discharge holes optimized for specific cooling needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If annular rings are placed in the motor case for cooling, then cooling function is provided, but the motor volume increases and the number of discharge positions is limited

Engineering Contradiction:
Improvecooling effectVSAvoidmotor volume
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

The cooling system is segmented into multiple independent discharge portions (first discharge portion and second discharge portion) located at different positions on the motor case. This allows the cooling function to be distributed across multiple locations rather than requiring a single large annular ring, thereby improving cooling efficiency without significantly increasing motor volume.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The discharge portions are arranged in different axial positions and radial locations on the motor case, utilizing three-dimensional space more effectively. This dimensional distribution allows multiple discharge points without requiring additional radial space, thus providing comprehensive cooling coverage while maintaining compact motor dimensions.

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

2Temperature

If annular rings are placed in the motor case for cooling, then cooling function is provided, but the number of discharge positions is limited

Engineering Contradiction:
Improvecooling effectVSAvoidnumber of discharge positions
Core Design Contradiction:
TemperatureVSAdaptability or versatility

Solution Approach 1:

The cooling system is segmented into multiple independent discharge portions (first discharge portion and second discharge portion) located at different positions on the motor case. This allows the cooling function to be distributed across multiple locations rather than requiring a single large annular ring, thereby improving cooling efficiency without significantly increasing motor volume.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The motor case serves multiple functions: it provides structural housing and simultaneously acts as a cooling medium channel and discharge structure. The case is designed with integrated cooling channels and multiple discharge portions, allowing it to perform both containment and thermal management functions, thereby increasing design flexibility without adding separate cooling components.

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

3Temperature

If cooling medium channels are added to the motor case, then cooling efficiency is improved, but the device complexity increases

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

Solution Approach 1:

The cooling medium channels are merged with the motor case structure itself, forming an integrated design where the case walls serve as channel boundaries. This eliminates the need for separate channel components and reduces assembly complexity while maintaining effective cooling pathways from the cooling medium supply to multiple discharge portions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The motor case serves multiple functions: it provides structural housing and simultaneously acts as a cooling medium channel and discharge structure. The case is designed with integrated cooling channels and multiple discharge portions, allowing it to perform both containment and thermal management functions, thereby increasing design flexibility without adding separate cooling components.

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

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 design achieves efficient cooling of motor components like coil ends and bearings while reducing the required space, maintaining compactness, and improving lubrication and cooling medium flow.

Implementation Method 1

The cooling medium channel includes at least a first channel through which a cooling medium flows in a vertical up-down direction. The cooling medium is discharged in the axial direction from the cooling medium channel through the discharge portions toward inside of the motor case.

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 2

The design achieves efficient cooling of motor components like coil ends and bearings while reducing the required space

Methodology Applied
Scientific EffectHeat transfer:

Data Source

PatentEP4712319A2motor
Publication Date: 2026.03.18 TOYOTA JIDOSHA KK
  • EP4712319A2 patent drawingFigure 1
  • EP4712319A2 patent drawingFigure 2~3
  • EP4712319A2 patent drawingFigure 4~5

AI summary

A motor (2) includes: a shaft (4); a rotor (6) fixed to the shaft (4); a stator (8) having an annular shape about a central axis of the rotor (6); and a motor case (20) that houses the rotor (6) and the stator (8). The motor case (20) includes a cooling medium channel (40) and discharge portions (50) in a surface of the motor case (20) that faces the stator (8) in an axial direction of the central axis. The cooling medium channel includes at least a first channel (42) through which a cooling medium flows in a vertical up-down direction. The cooling medium is discharged in the axial direction from the cooling medium channel (40) through the discharge portions (50, 150) toward the inside of the motor case (20).