Motor Housing Assembly with Thermally Conductive Polymeric Layer

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Solution Overview

Problem

Thermal conduction from motors is restricted by clearance gaps or air spaces, leading to elevated operating temperatures that affect motor efficiency and durability, potentially causing overheating and thermal stress.

Innovation Solution

A motor housing assembly with a thermally conductive polymeric layer interposed between the stator and motor housing, which displaces air and enhances heat transfer, while also stabilizing the stator position and damping vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a clearance gap or air space is maintained between the stator and motor housing, then the stator can be easily assembled into the housing, but heat transfer from the motor is restricted due to the poor thermal conductivity of air

Engineering Contradiction:

Improveease of assemblyVSAvoidmotor operating temperature

Core Design Contradiction:

Ease of manufactureVSTemperature

Solution Approach 1:

A thermally conductive polymeric layer is introduced as an intermediary material between the stator and motor housing. This layer replaces the air gap while providing superior thermal conductivity to facilitate heat transfer from the motor, thereby resolving the contradiction between ease of assembly and motor temperature control

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The thermal conductivity parameter of the material in the gap is changed from air (poor conductor) to a thermally conductive polymeric material (good conductor). This parameter change enables effective heat transfer while maintaining the gap structure for easy assembly

Inventive Principle:

Principle #35Parameter changes

2Temperature

If the stator is tightly fitted to the motor housing to improve heat transfer, then thermal conductivity improves, but stress is applied to the stator laminations during assembly and operation

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidstator lamination stress

Core Design Contradiction:

TemperatureVSStrength

Solution Approach 1:

A flexible polymeric layer is used between the rigid stator and housing. This flexible layer provides thermal conduction while accommodating dimensional variations and preventing stress concentration on the stator laminations, thus resolving the contradiction between heat transfer efficiency and structural strength

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The polymeric layer combines thermal conductivity with mechanical compliance properties. This composite material approach enables simultaneous achievement of good thermal contact and stress reduction, resolving the contradiction between heat transfer and structural integrity

Inventive Principle:

Principle #40Composite materials

3Temperature

If motor control systems restrict motor output to prevent overheating, then motor temperature is controlled, but motor efficiency and performance are reduced

Engineering Contradiction:

Improvemotor temperature controlVSAvoidmotor output torque

Core Design Contradiction:

TemperatureVSProductivity

Solution Approach 1:

The passive thermal management approach (restricting motor output) is replaced with an active thermal conduction solution (thermally conductive polymeric layer). This substitution allows the motor to operate at full output while the improved heat transfer actively manages temperature, resolving the contradiction between temperature control and productivity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Improves motor efficiency, reduces overheating and thermal stress, and increases the operating torque limit by effectively transferring heat and minimizing stress on motor components.

Implementation Method 1

The polymeric layer is configured as a thermally conductive layer, having a thermal conductivity greater than the thermal conductivity of air, such that the polymeric layer is configured to transfer heat from the stator to the housing to contribute to cooling of the motor in use

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

Heat transfer from a motor may be restricted by one or more clearance gaps or air spaces between components of the motor, such as between a stator and a motor housing, which reduce heat transfer from the motor due to the poor thermal conductivity, e.g., the insulating properties, of the air present in the gap or space

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS9356493B2Method of making a motor housing assembly

Publication Date: 2016.05.31 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A motor housing assembly is formed by positioning a stator relative to a motor housing to configure a fillable gap between the stator and the motor housing, and filling the fillable gap is at least partially with a polymeric material to form a thermally conductive layer. The polymeric material may include a metallic filler material. The thermally conductive layer is in contact with an exterior surface of the stator and an interior surface of the motor housing adjacent the exterior surface of the stator, and is configured to cover at least half of the exterior surface. A method to form the thermally conductive layer includes injecting a high flow polymeric material through a port defined by the housing and in fluid communication with the fillable gap.