Sliding Member Coating with Irregular Hard Particles for Rapid Wrapping

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Solution Overview

Problem

Conventional sliding material compositions fail to provide a rapid wrapping effect and sufficient wear resistance for mating members subjected to hardening treatments, as they either lead to increased surface roughness or slow wrapping transitions.

Innovation Solution

A sliding member system with a coating layer comprising a binder resin, molybdenum disulfide, and irregularly shaped hard substance particles, where the particles are 2 to 10 times larger than the mating member's surface roughness and have a hardness equal to or greater than the mating member, excluding spherical and acute-angle forms, and the mating member lacks a ferrite phase.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If acute-angled particles are used in the sliding material composition, then the wrapping effect occurs rapidly, but the wearing away of the mating member continues to proceed and increases the surface roughness after wrapping

Engineering Contradiction:
Improvewrapping speedVSAvoidsurface roughness
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The patent changes the geometric parameters of the hard particles from acute-angled to irregular shapes with rounded corners (where the radius of curvature at corners is 0.01 to 10 times the average particle diameter). This parameter change maintains the rapid wrapping effect while preventing continuous wearing away and roughness increase, as the rounded corners reduce stress concentration and prevent particle fragmentation that would otherwise increase surface roughness.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If spherical particles are used in the sliding material composition, then the surface roughness after wrapping is sufficient, but the wrapping speed is slow

Engineering Contradiction:
Improvesurface roughnessVSAvoidwrapping speed
Core Design Contradiction:
Manufacturing precisionVSSpeed

Solution Approach 1:

The patent employs asymmetric irregular shapes for the hard particles rather than perfectly spherical shapes. The particles have rounded corners with specific radius ratios that create asymmetric stress distribution during sliding, enabling both rapid wrapping action and maintained surface smoothness. This asymmetric design combines the advantages of spherical particles (smoothness) with the wrapping effectiveness of non-spherical particles.

Inventive Principle:
Principle #4Asymmetry

3Strength

If the hard substance particles have high hardness to provide wear resistance, then the wrapping effect is enhanced, but the particles may cause increased surface roughness through excessive wear on the mating member

Engineering Contradiction:
Improvewear resistanceVSAvoidsurface roughness
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent optimizes the particle shape parameters (rounded corners with specific radius ratios) to balance hardness and surface finish. The rounded corner geometry allows high-hardness particles to maintain wear resistance while reducing stress concentration that would lead to mating member surface degradation. This parameter optimization enables the particles to wrap and protect the surface without creating excessive roughness.

Inventive Principle:
Principle #35Parameter changes

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 system achieves rapid and stable wrapping of the mating member, enhancing wear resistance and seizure resistance while maintaining a smooth surface, as demonstrated by wear tests showing reduced surface roughness and wear depth.

Implementation Method 1

a surface of each sliding member is coated with a sliding material composition which is to be functioning as a lubricating film in each sliding section

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

Hard powder contained in a sliding material composition is expected to have a so-called wrapping effect which can smooth the surface of a mating member by wrapping a roughened portion of the mating member

Methodology Applied
Scientific EffectWrapping effect:

Implementation Method 3

the sliding member is capable of rapidly wrapping a mating member, and reducing the surface roughness of the mating member after wrapping

Methodology Applied
Scientific EffectWear resistance: Wear

Data Source

PatentEP2762552B1Sliding member and sliding material composition
Publication Date: 2019.03.06 TAIHO KOGYO CO LTD
  • EP2762552B1 patent drawingFigure 1~2
  • EP2762552B1 patent drawing

AI summary

An object of the present invention is to provide a sliding member capable of rapidly wrapping a mating member, and reducing the surface roughness of the mating member after wrapping. The present invention relates to a sliding member for sliding with a mating member subjected to hardening treatment, the sliding member including a coating layer containing a binder resin, molybdenum disulfide, and hard substance particles in massive form.