Lead-Free Sliding Bearing Layer With Higher Modulus and Wear Resistance
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Solution Overview
Problem
Existing sliding members with resin-based coatings face challenges in achieving improved elastic modulus to prevent deformation and maintain contact area stability under external forces, particularly in lead-free formulations.
Innovation Solution
A sliding member with a three-layer structure comprising a metallic substrate, a porous metal or alloy layer, and a lead-free resin composition that includes a zinc compound and either carbon fiber or iron oxide, or both, as essential additives, along with optional additives like barium sulfate, aramid fibers, graphite, or molybdenum disulfide, to enhance elastic modulus and abrasion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a lead-free resin composition is used as a sliding material, then harmful effects to human health are eliminated, but the elastic modulus and deformation resistance are insufficient
Solution Approach 1:
The patent uses a composite resin composition containing fluororesin as the base material, zinc compound as essential additive (0.1-10 wt%), and optional additives including aramid fibers, graphite, molybdenum disulfide, barium sulfate, and calcium compounds. This composite structure combines the low friction of fluororesin with the high modulus and abrasion resistance of the additive particles, achieving both health safety and mechanical performance.
Solution Approach 2:
The patent optimizes the content parameters of various additives to achieve the desired elastic modulus. Specifically, zinc compound content is controlled at 0.1-10 wt%, with optional additives totaling 0-20 wt%. By precisely controlling these compositional parameters, the resin composition achieves sufficient elastic modulus while maintaining lead-free safety.
2Ease of operation
If a resin-based sliding coating is used, then good slidability is achieved, but abrasion resistance and load capacity are insufficient
Solution Approach 1:
The patent creates a composite sliding coating by combining fluororesin with abrasive-resistant additives such as graphite, molybdenum disulfide, and aramid fibers. The fluororesin matrix provides low friction and good slidability, while the embedded additive particles provide abrasion resistance and load capacity, solving the contradiction between ease of sliding and reliability.
Solution Approach 2:
The patent creates a multi-phase structure where different materials perform different functions: fluororesin provides the sliding surface with low friction, while dispersed additive particles provide localized abrasion resistance and load bearing. This local differentiation of material properties allows the coating to simultaneously achieve good slidability and high abrasion resistance.
3Strength
If the elastic modulus of the resin composition is increased, then deformation of the sliding layer is prevented, but the contact area stability under external forces deteriorates
Solution Approach 1:
The patent optimizes the content of zinc compound (0.1-10 wt%) and optional additives to achieve a balance where the elastic modulus is sufficiently high to prevent deformation, while the total additive content (0-20 wt%) remains controlled to maintain contact area stability. This precise parameter control resolves the contradiction between strength and compositional stability.
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 improved elastic modulus and abrasion resistance of the resin composition prevent deformation and maintain contact area stability, enhancing the sliding member's performance and ride quality in applications like shock absorbers by managing friction forces effectively.
Implementation Method 1
a resin composition for forming a sliding layer contains a predetermined amount of a zinc compound, and further contains at least one of a carbon fiber and an iron oxide, so that an elastic modulus can be improved
Implementation Method 2
a powder of a Cu-based alloy or the like has been sintered on a metal support layer so as to be porous and a rough surface is formed, and a resin composition is impregnated to the rough surface and is baked
Data Source
AI summary
A sliding member includes a metallic substrate, a porous layer formed on a surface of the metallic substrate, and a sliding layer that covers the porous layer. The porous layer is made of a metal itself or an alloy composition. The sliding layer is made of a lead-free resin composition. The resin composition contains an essential additive, optionally an optional additive, and a fluororesin. The essential additive is any one of a combination of a zinc compound and a carbon fiber, a combination of a zinc compound and an iron oxide, and a combination of a zinc compound, a carbon fiber and an iron oxide. A total content of the essential additive and the optional additive is 10 vol % or more and 35 vol % or less in the resin composition.