Mid-Turbine Frame Piston Seal Ring Surface Coatings for Low Friction

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Solution Overview

Problem

Piston seal rings in gas turbine engines experience progressive wear and degradation due to high operation temperatures and vibratory motion, leading to significant friction and wear issues, especially at low temperatures.

Innovation Solution

The implementation of a glaze layer of oxide particles on piston seal rings and interfacing components through surface treatments like laser glazing or flame-induced oxidation, combined with cobalt-based wear-resistant coatings, to reduce friction and enhance wear resistance across a wide temperature range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional piston seal rings are used without surface modification, then the structure remains simple and manufacturing is easier, but wear resistance and friction performance deteriorate significantly under high temperature and vibratory conditions

Engineering Contradiction:
Improvewear resistanceVSAvoidsurface treatment complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies surface modification treatments (laser glazing, flame-induced oxidation, or cobalt-based coatings) to the piston seal rings before installation. This preliminary action creates a protective glaze layer or wear-resistant coating that will function during operation, resolving the contradiction by preparing the surface in advance to withstand high temperature and vibratory conditions without requiring complex operational modifications

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent modifies the surface parameters of the piston seal rings through controlled oxidation or coating application. By changing the surface chemical composition and physical structure (creating oxide glaze layers or metal coatings), the wear resistance and friction characteristics are significantly improved while maintaining the basic ring structure, thus resolving the contradiction between reliability improvement and device complexity

Inventive Principle:
Principle #35Parameter changes

2Temperature

If high operation temperatures are endured without surface modification, then the operating range is maintained, but progressive wear and degradation accelerate significantly

Engineering Contradiction:
Improveoperating temperature rangeVSAvoidcomponent lifespan
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent changes the thermal and chemical parameters of the seal ring surface through oxidation or coating. The resulting glaze layer or coating has enhanced thermal stability and chemical resistance, allowing the component to maintain reliability at high operating temperatures (up to 1600°F/871°C) where conventional unmodified rings would rapidly degrade

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite surface structure by forming oxide glaze layers or applying cobalt-based coatings over the base metal substrate. This composite material system combines the thermal conductivity and structural integrity of the base metal with the high-temperature oxidation resistance and wear resistance of the surface layer, enabling reliable operation across extended temperature ranges

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If vibratory motion is subjected without surface modification, then the operational functionality is maintained, but friction and wear increase significantly

Engineering Contradiction:
Improvesealing functionalityVSAvoidfriction resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies surface modification treatments in advance to create a low-friction glaze layer or wear-resistant coating on the piston seal rings. This preliminary action ensures that when vibratory motion occurs during operation, the modified surface already has the necessary friction and wear resistance properties, maintaining sealing functionality without suffering from accelerated degradation

Inventive Principle:
Principle #10Preliminary action

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 surface modification techniques result in a significant reduction in wear and friction, extending the lifespan of piston seal rings and interfacing components, and improving the overall efficiency and reliability of gas turbine engines by forming a solid-lubricant glaze layer that accommodates interfacial stresses and maintains performance across varying temperatures.

Implementation Method 1

at least one of the piston seal ring, the mid-turbine frame vane component or the interfacing component includes a glaze layer of oxide particles fabricated from a surface treatment or surface modification

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

the surface treatment or surface modification includes at least one of laser glazing, laser-induced oxidation, laser-assisted oxide deposition, pulse laser deposition

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 3

the surface treatment or surface modification includes at least one of laser glazing, laser-induced oxidation, laser-assisted oxide deposition, pulse laser deposition, or flame-induced oxidation surface treatments or modifications

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP4353955A1Methods for surface modification of mid-turbine frame piston seal rings and interfacing components to achieve low friction and high wear resistance
Publication Date: 2024.04.17 RTX CORP
  • EP4353955A1 patent drawingFigure 1
  • EP4353955A1 patent drawingFigure 2
  • EP4353955A1 patent drawingFigure 3

AI summary

The present disclosure provides assemblies (10), systems and methods for surface modification of piston seal rings (12) and interfacing components (18). More particularly, the present disclosure provides assemblies, systems and methods for surface modification of mid-turbine frame (MTF) piston seal rings (12) and interfacing components (18) in gas turbine engines to achieve low and/or reduced friction, and/or high and/or improved wear resistance.