Sliding Surface Texture for Lubricant Retention and Seizure Resistance

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Solution Overview

Problem

Existing sliding member technologies do not effectively optimize the profile relationship between large waviness and fine roughness, leading to insufficient lubricant retention and wettability, which results in reduced seizure resistance and durability.

Innovation Solution

Applying an isotropic texture with a valley area of 1000 µm²/mm to 20000 µm²/mm and RLo (λc: 0.08 mm) of 1% to 12% to the sliding surface of a low-hardness member to enhance lubricant retention and wettability, thereby improving seizure resistance and reducing friction and wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional surface roughness is applied, then manufacturing is simple, but seizure resistance is insufficient

Engineering Contradiction:
Improvesurface processing simplicityVSAvoidseizure resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention changes the parameters of surface texture by introducing a specific multi-scale structure with defined characteristics: large waviness with specific amplitude and wavelength, and fine roughness with specific RMS values. This parameter optimization achieves enhanced seizure resistance while maintaining compatibility with conventional manufacturing processes like grinding or honing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The surface structure is essentially a composite of two different texture scales, combining the benefits of large-scale waviness (oil retention) and fine-scale roughness (lubricant distribution). This composite surface structure achieves superior seizure resistance compared to single-scale roughness, while still being manufacturable using standard surface treatment processes.

Inventive Principle:
Principle #40Composite materials

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 optimized texture improves lubricity and seizure resistance, extending the life of the sliding member by enhancing lubricant retention and supply to the contact surface.

Implementation Method 1

large waviness functions as oil reservoirs

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

fine irregularities function to supply base oil of grease or lubricating oil to a contact surface

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 3

a first member and a second member having a higher hardness than the first member slide against each other via a lubricant

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP4596912A1Sliding component
Publication Date: 2025.08.06 NSK LTD
  • EP4596912A1 patent drawingFigure 1
  • EP4596912A1 patent drawingFigure 2
  • EP4596912A1 patent drawingFigure 3A

AI summary

Provided is a sliding component in which a low-hardness first component and a high-hardness second component slide with a lubricant therebetween, wherein the configurational relationship between microroughness and large undulations imparted to the first component is optimized to enhance both lubricant retention and wettability, and to further improve anti-seizing properties. In the sliding component, the first component and the second component with higher hardness than the first component slide with a lubricant therebetween. The sliding component is imparted, in an area contacting the second component in the first component, with an isotropic texture in which the valley surface area is 1000 µm2/mm to 20000 µm2/mm, and the RLo (λc: 0.08 mm) is from 1% to 12%.