Motor Stator Potting for Filling Narrow Cooling Tube Gaps

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Solution Overview

Problem

The narrow gap between the cooling tube and the stator in electric motors poses a challenge for filling with potting material, which is essential for thermal connection and electrical insulation, especially in space applications where convective heat transfer is not possible, and existing methods using only vacuum suction are often ineffective.

Innovation Solution

A method involving a combination of vacuum suction and air pressure to draw the potting material into the gap, followed by applying pressure in a pressure vessel to ensure complete filling and curing, using a suitable material like Bacon P-82C to maintain electrical insulation and thermal connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If only vacuum suction is used to fill the gap, then the process is simple, but the narrow gap cannot be completely filled

Engineering Contradiction:

Improveprocess simplicityVSAvoidgap filling completeness

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent combines vacuum suction with pressure application to fill the narrow gap. The process uses vacuum to draw potting material into the gap, then applies pressure to push the material further in and ensure complete filling. This combination resolves the contradiction by maintaining process simplicity while achieving complete gap filling.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent employs periodic action by sequentially applying vacuum suction first, then applying pressure in stages. The pressure is applied, released, and reapplied to progressively fill the narrow gap completely. This periodic approach ensures thorough filling while keeping the process manageable and simple.

Inventive Principle:

Principle #19Periodic action

2Reliability

If the gap is made narrower to improve cooling efficiency, then cooling efficiency increases, but filling the gap with potting material becomes more difficult

Engineering Contradiction:

Improvecooling efficiencyVSAvoidgap filling difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges vacuum suction with pressure application to overcome the difficulty of filling narrow gaps. By combining these two forces, the process can successfully fill even very narrow gaps (e.g., 0.002 inches) that would be impossible to fill with vacuum alone, thereby maintaining high cooling efficiency while solving the filling difficulty.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the pressure parameter during the filling process. It starts with vacuum (negative pressure) to draw material in, then transitions to positive pressure to push material into the narrowest parts of the gap. This parameter change enables complete filling of narrow gaps without compromising cooling efficiency.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If pressure is applied to push potting material into the gap, then complete filling is achieved, but the process complexity increases

Engineering Contradiction:

Improvegap filling completenessVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines vacuum suction and pressure application in a single integrated process. The vacuum chamber serves dual purposes: creating vacuum for suction and then allowing pressure application from the same chamber. This merging avoids the need for separate equipment and processes, maintaining simplicity while achieving complete gap filling.

Inventive Principle:

Principle #5Merging (Combining)

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 approach effectively fills the narrow gaps between the cooling tube and the stator, ensuring reliable thermal contact and electrical insulation, preventing cracking and potential short circuits, while maintaining high cooling efficiency.

Implementation Method 1

A method involving a combination of vacuum suction and air pressure to draw the potting material into the gap

Methodology Applied

Scientific EffectVacuum suction: Vacuum

Implementation Method 2

applying pressure in a pressure vessel to ensure complete filling

Methodology Applied

Scientific EffectAir pressure: Pressure Increase

Implementation Method 3

the potting material electrically insulates the cooling tube from the stator and thermally connect the cooling tube to the stator

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

the potting material electrically insulates the cooling tube from the stator

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Data Source

PatentEP4280435A1Motor stator potting

Publication Date: 2023.11.22 HAMILTON SUNDSTRAND CORP

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AI summary

A method (400) of manufacturing an electric motor assembly includes inserting (410) the pump motor stator into a vacuum chamber. The pump motor stator (100) comprises a housing (110) having a cavity (120) formed therein and a pump motor stator (130) located within the cavity. The pump motor stator contains an integral cooling tube (150) located radially inward of the stator. The method also includes applying (420) a vacuum to the pump motor stator in the vacuum chamber and flowing a potting material into a gap (G1) between the stator and the cooling tube and the stator, the gap (430) extending a first distance longitudinally between the stator and the cooling tube. Pressure (450) is applied to the potting material to push the potting material further into the gap.