Stator Core Cooling via Refrigerant Injection Port Orientation

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Solution Overview

Problem

There is a demand for more efficient cooling of the stator core in rotary electric machines using refrigerant injection, as existing systems may not effectively distribute the refrigerant for optimal heat dissipation.

Innovation Solution

A drive apparatus with a motor and stator core configuration that includes a first refrigerant injection portion with a strategically positioned injection port to inject refrigerant into the stator core, allowing for efficient cooling by directing the refrigerant to flow over the stator core's outer surface, thereby enhancing heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a refrigerant injection portion is provided to inject refrigerant into the stator core, then cooling efficiency is improved, but refrigerant distribution uniformity deteriorates

Engineering Contradiction:

Improvestator core cooling efficiencyVSAvoidrefrigerant distribution uniformity

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The injection port is divided into multiple injection holes (first injection holes and second injection holes) arranged at different positions and orientations. This segmentation allows refrigerant to be injected from multiple locations simultaneously, achieving uniform distribution across the stator core while maintaining effective cooling.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the stator core are targeted with specifically oriented injection holes. The first injection holes are oriented to cool one circumferential side while the second injection holes cool the other circumferential side, ensuring locally optimized cooling distribution throughout the entire stator core.

Inventive Principle:

Principle #3Local quality

2Temperature

If the injection port is positioned to cool the stator core effectively, then cooling efficiency is improved, but refrigerant may flow excessively over the fixing portions

Engineering Contradiction:

Improvestator core cooling efficiencyVSAvoidrefrigerant flow quantity

Core Design Contradiction:

TemperatureVSQuantity of substance

Solution Approach 1:

Instead of injecting refrigerant from above the fixing portions (which would cause excessive flow over them), the injection holes are positioned and oriented to inject refrigerant from below or at angles that direct flow onto the stator core body while bypassing the fixing portions. This inverted approach prevents unwanted refrigerant accumulation on fixing portions while maintaining cooling efficiency.

Inventive Principle:

Principle #13The other way round (Inversion)

3Device complexity

If a single injection port is used, then device complexity is reduced, but cooling coverage of both circumferential sides deteriorates

Engineering Contradiction:

Improveinjection port configurationVSAvoidcircumferential side cooling coverage

Core Design Contradiction:

Device complexityVSTemperature

Solution Approach 1:

The single injection port is segmented into multiple injection holes with different orientations. The first injection holes are oriented to cool one circumferential side while the second injection holes are oriented to cool the other circumferential side, achieving comprehensive cooling coverage while maintaining a relatively simple single-port structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The single injection port structure performs multiple cooling functions through its differentially oriented injection holes. It simultaneously cools both circumferential sides of the stator core, making the single port structure multi-functional in terms of cooling coverage.

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 solution effectively improves the cooling efficiency of the stator core by ensuring uniform refrigerant distribution, preventing excessive flow over fixing portions and ensuring adequate cooling of both circumferential sides, thus enhancing the overall performance of the drive apparatus.

Implementation Method 1

inject a refrigerant into the stator core... directing the refrigerant to flow over the stator core's outer surface, thereby enhancing heat dissipation

Methodology Applied

Scientific EffectHeat dissipation: Convection

Data Source

PatentUS11496023B2Drive apparatus

Publication Date: 2022.11.08 NIDEC CORP(JP)

AI summary

A drive apparatus includes: a motor having a rotor and a stator core; a housing; and a first injection port to inject a refrigerant into the stator core. The stator core includes: a core body surrounding the rotor; and a fixing portion projecting radially outward from the core body and fixed to the housing. The fixing portion includes an upper fixing portion. The first injection port is lower than an end portion of the upper fixing portion. The upper fixing portion is on one circumferential side of the first injection port. The first injection port is open in a first direction facing a directly lower side or a second direction angled to the one circumferential side with respect to the first direction, and is facing a portion on the other circumferential side of a boundary with an end portion of the upper fixing portion on the other circumferential side.