Anti-galling Method for Metallic Components

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Solution Overview

Problem

Mechanical assemblies with metallic components, such as pivot-bushing assemblies, experience galling due to excessive sliding friction, leading to machine downtime and frequent maintenance, despite existing lubrication and thermal treatments.

Innovation Solution

An anti-galling method involving thermal treatments to increase surface hardness, surface grinding, washing to remove contaminants, shot peening to induce residual compression, and applying a molybdenum disulfide layer to enhance surface adhesion and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lubricants are interposed between pivot and bushing to reduce friction, then galling resistance is improved, but periodic maintenance is required to restore lubricant conditions

Engineering Contradiction:
Improvegalling resistanceVSAvoidperiodic maintenance time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The surface is preliminarily treated with shot peening to create compressive residual stresses and roughness before final assembly, pre-conditioning the surface to resist galling without requiring subsequent maintenance interventions

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The shot-peened surface structure self-generates lubricant retention through its roughness profile and compressive stress field, eliminating the need for external maintenance to restore lubricant conditions

Inventive Principle:
Principle #25Self-service

2Strength

If thermal treatment and grinding are applied to pivot surface, then surface hardness is improved, but galling resistance is not sufficiently enhanced

Engineering Contradiction:
Improvesurface hardnessVSAvoidgalling resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The surface parameters are fundamentally changed by shot peening, creating compressive residual stresses and micro-roughness that transform the surface's interaction with lubricant and opposing surface, providing galling resistance beyond what hardness alone can achieve

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The surface structure becomes composite in nature, combining the base metallic material with a shot-peened surface layer that has different mechanical properties (compressive stresses, altered roughness), creating a multi-layered protective system

Inventive Principle:
Principle #40Composite materials

3Reliability

If frequent periodic maintenance is performed to avoid galling, then machine downtime is reduced, but operational costs increase

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoidmaintenance complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The shot peening treatment is performed preliminarily during manufacturing, establishing long-term galling resistance that eliminates the need for frequent maintenance interventions throughout the component's service life

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

Significantly reduces galling occurrences, minimizing maintenance needs and ensuring long-term mechanical coupling durability with improved lubricant distribution and surface stability.

Implementation Method 1

subjecting at least one of the at least two components mutually coupled with at least one degree of freedom, made of metallic material, to a first preliminary step of thermal treatments to increase surface hardness

Methodology Applied
Scientific EffectThermal treatment: Heat Treatment

Implementation Method 2

performing a second step of shot peening said at least one portion of the surface of the at least one component previously subjected to washing

Methodology Applied
Scientific EffectShot peening: Shot Peening

Implementation Method 3

performing a third step of applying a layer of molybdenum disulfide on said at least one portion of the at least one component previously subjected to shot peening

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3169757B1Anti-galling method for treating materials
Publication Date: 2022.01.05 ITALTRACTOR ITM SPA
  • EP3169757B1 patent drawingFigure 1

AI summary

An anti-galling method for treating materials, which provides for subjecting at least one of the at least two components mutually coupled with at least one degree of freedom, made of metallic material, to a first preliminary step of thermal treatments to increase surface hardness and to a second preliminary step of surface grinding, which consists in - performing a first step of washing at least one portion of the surface of the at least one component subjected previously to the preliminary steps; - performing a second step of shot peening the at least one portion of the surface of the at least one component previously subjected to washing; - performing a third step of applying a layer of molybdenum disulfide to the at least one portion of the at least one component previously subjected to shot peening.