Compressor Valve Coating for Fatigue and Leakage

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Solution Overview

Problem

In reciprocating compressors, metal fatigue occurs due to pressure differences, leading to valve contact issues, refrigerant leakage through sintered metal vacancies, reduced efficiency, and noise generation, especially with low-viscosity lubricant use and inverter-driven high-efficiency operations.

Innovation Solution

A surface treatment film with multiple coating layers, including synthetic resin and solid lubricant, is applied to contact and slide surfaces, where the solid lubricant content decreases from the inner to the outer layers, enhancing abrasion resistance and adhesion while mitigating impact forces and maintaining performance over time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a solid lubricant is applied on the slide surface of a crankshaft to reduce friction, then the lubrication performance is improved, but the adhesion to the metal surface deteriorates over time due to abrasion

Engineering Contradiction:
Improvelubrication performanceVSAvoidservice life of lubricant layer
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The lubricant layer is segmented into multiple layers with different functions: a first layer containing solid lubricant for low friction, and a second layer with higher adhesion for durability. This segmentation allows each layer to optimize its specific function rather than requiring a single material to fulfill all requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses composite material structure with two distinct lubricant layers applied sequentially. The first layer uses solid lubricant particles in a binder, while the second layer uses a different binder composition with higher adhesion properties, creating a composite structure that combines low friction with long-term durability.

Inventive Principle:
Principle #40Composite materials

2Productivity

If the valve plate is made of sintered metal material to improve productivity, then the manufacturing efficiency is improved, but refrigerant leakage occurs through vacancies in the sintered structure

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidsealing performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention intentionally utilizes the porous structure of sintered metal by filling the vacancies with a resin-based coating material. This transforms the harmful porosity into a beneficial feature where the resin occupies the voids and creates a sealed surface, maintaining the manufacturing advantages of sintered metal while eliminating leakage.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

A resin-based coating material acts as an intermediary between the sintered metal substrate and the external environment. This intermediate layer fills the vacancies and pores in the sintered structure, preventing refrigerant leakage while allowing the sintered metal to retain its structural integrity and manufacturing benefits.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Use of energy by moving object

If low-viscosity refrigerant oil is used to achieve energy saving, then the energy efficiency is improved, but the sealing performance between valve and valve seat deteriorates

Engineering Contradiction:
Improveenergy efficiencyVSAvoidsealing performance
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The invention changes the surface properties of the valve and valve seat by applying a resin-based coating, which modifies the contact characteristics. This allows low-viscosity refrigerant oil to be used while maintaining sealing performance, as the coated surface provides adequate friction and sealing without relying on high oil viscosity.

Inventive Principle:
Principle #35Parameter changes

4Use of energy by moving object

If the suction valve thickness is reduced to improve efficiency, then the compression efficiency is improved, but metal fatigue accumulation increases leading to breakage

Engineering Contradiction:
Improvecompression efficiencyVSAvoidvalve durability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The invention applies a resin-based coating film on the valve surface, which acts as a protective layer. This thin film reinforcement allows the valve to maintain reduced thickness for efficiency while the coating provides fatigue resistance and prevents breakage at stress concentration points.

Inventive Principle:
Principle #30Flexible shells and thin films

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 solution effectively reduces metal fatigue, minimizes refrigerant leakage, and decreases noise, ensuring long-term compressor reliability and efficiency by smoothing surfaces and maintaining lubrication, even under harsh operating conditions.

Implementation Method 1

A surface treatment film including synthetic resin and solid lubricant is applied to at least a portion of a contact surface or a slide surface

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

the coating layer located at an innermost side is larger in elastic deformation amount than the coating layer located at an outermost side

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2933488B1Method for manufacturing a compressor
Publication Date: 2020.09.30 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP2933488B1 patent drawingFigure 1
  • EP2933488B1 patent drawingFigure 2
  • EP2933488B1 patent drawingFigure 3

AI summary

A contact member or a slide member of the present invention comprises a surface treatment film (160) including two or more coating layers stacked together, in at least a portion of a contact surface or a slide surface thereof, wherein each of the coating layers includes synthetic resin and a solid lubricant, and wherein the solid lubricant (162) of the coating layer located at an innermost side is lower in content percentage than the solid lubricant of the coating layer located at an outermost side. A contact member or a slide member of the present invention comprises a surface treatment film (160) including two or more coating layers stacked together, in at least a portion of a contact surface or a slide surface thereof, each of the coating layers includes synthetic resin, and the coating layer located at an innermost side is larger in elastic deformation amount than the coating layer located at an outermost side.