Lamellar-Coated Blade Root Bearing for High-Pressure Lubrication

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Solution Overview

Problem

Blade root bearings in aeronautics face lubrication challenges due to high contact pressure and oscillating conditions, which cause lubricant loss and reduced lifespan, especially across a wide temperature range from -55°C to +170°C.

Innovation Solution

A blade root bearing with a coating of chemical compounds having a lamellar structure, such as WS2, combined with a suitable lubricant, ensures effective lubrication by maintaining a lubricating film under high pressure and temperature variations, adhering to the surface and interacting to reform the coating if damaged.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a standard lubricant is used in the blade root bearing, then the bearing can operate under normal conditions, but the lubricant is forced out of contact areas by high contact pressure and centrifugal forces, leading to lubrication loss and reduced bearing lifespan

Engineering Contradiction:
Improvebearing lifespanVSAvoidlubricant retention
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies a coating of chemical compound with lamellar structure (such as WS2, MoS2, or graphite) on the rolling paths and/or contact surfaces of the rolling bodies. This coating changes the surface parameters of the bearing components, providing extreme pressure resistance and preventing lubricant expulsion under high contact pressure (up to 3 GPa) and centrifugal forces. The lamellar structure allows for easy shear between layers, maintaining lubrication effectiveness under severe operating conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent combines a lubricant with a coating of chemical compound having lamellar structure to create a composite lubrication system. The coating material (such as tungsten disulfide WS2, molybdenum disulfide MoS2, or graphite) forms a composite structure with the base bearing materials, providing enhanced tribological properties. This composite approach allows the bearing to withstand both high contact pressure and centrifugal forces while retaining lubrication effectiveness across the operating temperature range.

Inventive Principle:
Principle #40Composite materials

2Stress or pressure

If the lubricant viscosity is increased to withstand high contact pressure and centrifugal forces, then the lubricant can maintain contact under load, but the lubricant solidifies at minimum temperatures (-55°C) and cannot be applied across the wide temperature range

Engineering Contradiction:
Improvecontact pressure resistanceVSAvoidtemperature range adaptability
Core Design Contradiction:
Stress or pressureVSTemperature

Solution Approach 1:

The patent specifies a coating of chemical compound with lamellar structure that provides temperature-stable tribological properties. The coating materials (WS2, MoS2, graphite) maintain their lubricating characteristics across the wide temperature range from -55°C to +170°C, preventing the viscosity problems that affect conventional lubricants. The coating's physical and chemical properties remain stable throughout this temperature range, enabling consistent performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies the lamellar coating specifically to the rolling paths and/or contact surfaces of the rolling bodies where extreme pressure and temperature conditions occur. This localized application provides the necessary pressure resistance and temperature adaptability precisely where needed, while the rest of the bearing structure can be optimized for other requirements. The coating creates a localized zone with enhanced tribological properties.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the bearing operates under high contact pressure (3 GPa) and oscillating conditions, then the bearing can fulfill its orienting function, but the lubricant is expelled from contact areas and projected outward by centrifugal forces, causing deterioration

Engineering Contradiction:
Improvebearing functionVSAvoidlubrication maintenance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies a coating of chemical compound with lamellar structure (such as WS2, MoS2, or graphite) on the rolling paths and/or contact surfaces of the rolling bodies. This coating changes the surface parameters of the bearing components, providing extreme pressure resistance and preventing lubricant expulsion under high contact pressure (up to 3 GPa) and centrifugal forces. The lamellar structure allows for easy shear between layers, maintaining lubrication effectiveness under severe operating conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a coating layer that can be relatively thin compared to the bearing dimensions, yet provides substantial protection against lubricant expulsion and surface wear. The coating acts as a sacrificial or protective layer that maintains the bearing's lubrication under extreme conditions, allowing the bearing to function reliably despite the harsh operating environment with oscillating conditions and high centrifugal forces.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 provides consistent lubrication over the entire temperature range, resisting high contact pressures and centrifugal forces, thereby extending the lifespan of the bearing and maintaining its operational integrity.

Implementation Method 1

a coating of chemical compound with lamellar structure

Methodology Applied
Scientific EffectLamellar structure: Lamella

Implementation Method 2

The combination of the lamellar chemical compound coating and the lubricant allows the blade root bearing to be lubricated despite high contact pressure and oscillations

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 3

adhering to the surface and interacting to reform the coating if damaged

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3680168B1Lubricated blade root bearing
Publication Date: 2023.11.08 NTN EUROPE
  • EP3680168B1 patent drawingFigure 1
  • EP3680168B1 patent drawingFigure 2
  • EP3680168B1 patent drawingFigure 3

AI summary

The invention relates to a lubricated blade foot bearing comprising a coating of a lamellar structure chemical compound.