Lead-Free Sliding Layer Composition for Bearing Wear Resistance

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Solution Overview

Problem

Existing sliding members with resin-based coatings face challenges in achieving improved elastic modulus and abrasion resistance to prevent deformation and maintain effective contact area under external forces, particularly in lead-free alternatives.

Innovation Solution

A resin composition incorporating a zinc compound, iron oxide, and carbon fiber is used to enhance the elastic modulus of the sliding layer, preventing deformation and maintaining contact area, with specific volume percentages of these additives ensuring optimal performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a resin-based sliding layer is used to eliminate lead, then environmental safety is improved, but the elastic modulus and deformation resistance deteriorate

Engineering Contradiction:
Improvelead contentVSAvoidelastic modulus
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent applies composite materials by combining resin base material with multiple additives (zinc powder, iron oxide, carbon fiber) to create a sliding layer that maintains both environmental safety (lead-free) and mechanical strength (high elastic modulus). The zinc powder provides base reinforcement, iron oxide enhances hardness and wear resistance, and carbon fiber adds tensile strength, collectively achieving the desired elastic modulus without lead.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies parameter changes by optimizing the content ratios of different additives in the resin composition. Specifically, it controls zinc powder content at 5-50 wt%, iron oxide at 1-30 wt%, and carbon fiber at 0.1-10 wt%, along with adjusting particle size distributions. These parameter optimizations enable the sliding layer to achieve sufficient elastic modulus and deformation resistance while remaining lead-free.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If a resin-based sliding layer is used to eliminate lead, then environmental safety is improved, but the abrasion resistance deteriorates

Engineering Contradiction:
Improvelead contentVSAvoidabrasion resistance
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies composite materials by combining resin base material with multiple additives (zinc powder, iron oxide, carbon fiber) to create a sliding layer that maintains both environmental safety (lead-free) and mechanical strength (high elastic modulus). The zinc powder provides base reinforcement, iron oxide enhances hardness and wear resistance, and carbon fiber adds tensile strength, collectively achieving the desired elastic modulus without lead.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by creating a multi-component composite structure where each additive serves specific local functions: zinc powder provides base reinforcement and lubricity, iron oxide specifically enhances surface hardness and abrasion resistance, while carbon fiber provides tensile strength and crack resistance. This localized functional distribution within the composite achieves superior abrasion resistance.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the sliding layer is made softer to improve sliding performance, then sliding performance is improved, but the contact area stability under external force deteriorates

Engineering Contradiction:
Improvesliding performanceVSAvoidcontact area stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent applies composite materials by combining resin base material with multiple additives (zinc powder, iron oxide, carbon fiber) to create a sliding layer that maintains both environmental safety (lead-free) and mechanical strength (high elastic modulus). The zinc powder provides base reinforcement, iron oxide enhances hardness and wear resistance, and carbon fiber adds tensile strength, collectively achieving the desired elastic modulus without lead.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies parameter changes by optimizing the content ratios of different additives in the resin composition. Specifically, it controls zinc powder content at 5-50 wt%, iron oxide at 1-30 wt%, and carbon fiber at 0.1-10 wt%, along with adjusting particle size distributions. These parameter optimizations enable the sliding layer to achieve sufficient elastic modulus and deformation resistance while remaining lead-free.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3751162B1Sliding member and bearing
Publication Date: 2023.11.15 SENJU METAL IND CO LTD
  • EP3751162B1 patent drawingFigure 1~2
  • EP3751162B1 patent drawingFigure 3~4

AI summary

Provided is a sliding member having improved various characteristics such as elastic modulus, and a bearing using the sliding member. The sliding member 1 includes a metallic substrate 2, a porous layer 3 formed on a surface of the metallic substrate 2, and a sliding layer 5 that covers the porous layer 3. The sliding layer 5 is made of a lead-free resin composition 4, the resin composition 4 contains a zinc compound as an essential additive and further contains, as an essential additive, either of a carbon fiber or an iron oxide or both of the carbon fiber and the iron oxide. A content of the essential additive is 10 vol% or more and 35 vol% or less in the resin composition, and the remainder is a fluororesin.