Coolant Distribution Ring for Electric Motor Stator

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Solution Overview

Problem

Electric rotating machines in vehicles face inefficiencies in cooling stator windings, particularly the protruding ends, which can lead to heat-related limitations and potential thermal failures due to inadequate cooling systems.

Innovation Solution

The design incorporates a stator with inner and outer longitudinal grooves forming axial cooling channels, and a distribution ring with recesses that guide a coolant from the outer grooves to the protruding windings ends, enhancing cooling efficiency through gravity and pressure-assisted flow, using a non-magnetic, non-electric conductive material like plastic to reduce size and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a conventional cooling system is used for the stator core, then the cooling channels can cool the stator core, but the protruding windings ends cannot be effectively cooled

Engineering Contradiction:
Improvecooling effectivenessVSAvoidthermal failure risk
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The cooling system is segmented into two distinct pathways: axial cooling channels for the stator core and radial cooling channels through the distribution ring for the protruding windings ends. This segmentation allows each cooling pathway to be optimized for its specific target area, ensuring both the stator core and windings ends are effectively cooled

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The distribution ring acts as an intermediary component that receives coolant from the axial cooling channels and redistributes it through radial cooling channels to the protruding windings ends. This intermediary structure enables the coolant to reach areas that would otherwise be inaccessible from the main cooling system

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the distribution ring is made of magnetic or electrically conductive material, then it can be integrated with the stator core, but it increases size and cost

Engineering Contradiction:
Improveintegration with stator coreVSAvoiddistribution ring weight
Core Design Contradiction:
Device complexityVSWeight of moving object

Solution Approach 1:

The material parameters of the distribution ring are changed from magnetic/electrically conductive materials to non-magnetic and non-electrically conductive materials (such as plastics or composite materials). This parameter change allows the distribution ring to be integrated with the stator core while reducing weight and manufacturing cost, as these materials are lighter and easier to manufacture

Inventive Principle:
Principle #35Parameter changes

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 solution effectively cools the protruding windings ends, increases the compactness of the electric rotating machine, prevents hot-spots, and reduces the risk of thermal failure, while being cost-efficient and flexible in manufacturing.

Implementation Method 1

the coolant flows over the protruding windings ends under the effect of gravity and/or due to the pressure of the coolant to cool the protruding windings ends

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 2

the coolant flows over the protruding windings ends under the effect of gravity and/or due to the pressure of the coolant to cool the protruding windings ends

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 3

the coolant flows over the protruding windings ends under the effect of gravity and/or due to the pressure of the coolant to cool the protruding windings ends

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 4

the distribution ring comprises recesses providing an extension of the outer longitudinal grooves, the recesses being configured to guide the coolant from the outer longitudinal grooves towards the protruding windings end

Methodology Applied
Scientific EffectFluid flow guidance:

Data Source

PatentEP3993226A1Coolant distribution ring for electric motor
Publication Date: 2022.05.04 VALEO ELECTRIFICATION
  • EP3993226A1 patent drawingFigure 1~2
  • EP3993226A1 patent drawingFigure 3~4
  • EP3993226A1 patent drawingFigure 5~6

AI summary

The invention concerns a stator of an electric rotating machine, the stator comprising a housing, a stator core (1), windings, and a distribution ring (2), the stator core (1) having inner and outer (11) longitudinal grooves, the outer longitudinal grooves (11) and the housing forming axial cooling channels configured to channel a coolant; the windings being located within the inner longitudinal grooves and forming at each end of the stator core (1) protruding windings ends, the distribution ring (2) being contiguous to the stator core (1) and comprising recesses (21) extending the outer longitudinal grooves (11), the recesses (21) being configured to guide the coolant from the outer longitudinal grooves (11) towards the protruding windings ends, such that the coolant flows over the protruding windings ends under the effect of gravity and/or due to the pressure of the coolant.to cool the protruding windings ends.