Refrigerant Compressor Vane Coating for Wear-Resistant Sliding Contact

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Solution Overview

Problem

The existing refrigerant compressors face issues with adherence between layers and wear in the slide members, particularly when amorphous carbon layers are used, leading to potential separation or cracking under repeated stress.

Innovation Solution

A refrigerant compressor design featuring a base member with sequentially layered chromium, chromium-tungsten carbide, metal-containing amorphous carbon, and hydrogen-free amorphous carbon layers, along with a roller made of flake graphite cast iron, to enhance adherence and reduce wear by controlling layer content rates and hardness gradients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a nitrided layer is formed on the base member surface for hardening, then deformation of the base member is restricted and adherence between the base member and intermediate layer is improved, but adherence between the intermediate layer and amorphous carbon layer deteriorates, causing separation or crack under repeated stress

Engineering Contradiction:

Improvehardness of base memberVSAvoidadherence between intermediate layer and amorphous carbon layer

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The invention uses a composite coating structure with four distinct layers (chromium layer, alloyed layer, metal-containing amorphous carbon layer, and hydrogen-containing amorphous carbon layer) instead of a single material. Each layer serves a specific function: the chromium and alloyed layers provide hardness and deformation resistance, while the dual amorphous carbon layers ensure low friction and maintain good adherence to each other, resolving the contradiction between base member hardening and coating adherence

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Different regions of the coating have different properties tailored to their specific functions. The chromium layer provides oxidation resistance, the alloyed layer provides hardness gradient, the metal-containing amorphous carbon layer provides bonding interface, and the hydrogen-containing amorphous carbon layer provides low friction surface. This local differentiation allows each layer to optimize its performance without compromising overall adherence

Inventive Principle:

Principle #3Local quality

2Reliability

If multiple amorphous carbon layers are used to reduce friction, then wear resistance is improved, but separation or crack occurs between layers under repeated stress

Engineering Contradiction:

Improveanti-wear characteristicsVSAvoidstructural integrity of layered film

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The metal-containing amorphous carbon layer acts as an intermediary between the alloyed layer and the hydrogen-containing amorphous carbon layer. This intermediate layer with metal particles (tungsten, molybdenum, or nickel) provides a bonding bridge that maintains structural integrity while allowing the outer hydrogen-containing amorphous carbon layer to provide low friction and wear resistance

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the compositional parameters of the amorphous carbon layers by controlling metal particle content (0.1-10 at%) and hydrogen content. The metal-containing amorphous carbon layer has specific metal particle concentration that enhances adhesion, while the hydrogen-containing outer layer has optimized hydrogen content for low friction. These parameter optimizations prevent layer separation while maintaining wear resistance

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

This configuration significantly reduces wear depths of vanes and rollers, improving adherence and preventing cracks, resulting in a more reliable refrigerant compressor with enhanced anti-wear characteristics.

Implementation Method 1

forming a nitrided layer on a surface of a base member (core material), then hardening the base member

Methodology Applied

Scientific EffectHardening: Heat Treatment

Implementation Method 2

forming an intermediate layer and a single-layered or double-layered amorphous carbon layer(s) thereon

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Implementation Method 3

The roller is made of flake graphite cast iron containing molybdenum, nickel and chromium

Methodology Applied

Scientific EffectLubrication: Lubrication

Data Source

PatentUS20120174617A1Refrigerant compressor and refrigeration cycle apparatus

Publication Date: 2012.07.12 TOSHIBA CARRIER CORP

AI summary

A refrigerant compressor includes a compression unit having a roller and a vane for compressing refrigerant. The vane has a film having first to fourth layers on its metallic base member. The first layer is made of chromium. The second layer is made of chromium and tungsten-carbide. The third layer is made of metal-containing amorphous-carbon containing at least tungsten or tungsten-carbide. The fourth layer is made of non-metal-containing amorphous-carbon containing carbon and hydrogen. In the second layer, chromium content-rate on a first-layer side is larger than on a third-layer side, and tungsten-carbide content-rate on the third-layer side is larger than on the first-layer side. In the third layer, content-rate of the at least tungsten or tungsten-carbide on a second-layer side is larger than on a fourth-layer side. The roller with which an end-edge of the vane slidably-contacts is made of flake graphite cast iron containing molybdenum, nickel and chromium.