Rotary Compressor Vane Coating to Prevent DLC Peeling
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Solution Overview
Problem
Existing rotary compressors face issues with internal residual stress and peeling of diamond-like carbon layers due to thick intermediate layers and oxidation of tungsten, leading to increased costs and reduced durability.
Innovation Solution
A rotary compressor design featuring a vane with a single chromium layer, an intermediate coating layer with a chromium and carbon concentration gradient, and a diamond-like carbon layer on the sliding surface, formed using an ionic vapor deposition method, which reduces internal residual stress and improves bonding properties without the use of tungsten.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If multiple coating layers including alloy layers are used to improve sliding surface properties, then the hardness and wear resistance are improved, but the internal residual stress increases and the diamond-like carbon layer is easily peeled off
Solution Approach 1:
The invention removes the alloy layer containing tungsten from the coating structure. By extracting this problematic intermediate layer, the patent eliminates the source of oxidation and subsequent peeling while maintaining the necessary functional layers (chromium base layer and diamond-like carbon sliding layer) for wear resistance and low friction.
Solution Approach 2:
The patent employs a simplified composite coating structure consisting of a chromium base layer and a diamond-like carbon sliding layer. This composite structure achieves the desired balance between adhesion and sliding properties without requiring multiple intermediate alloy layers, thereby reducing internal stress and preventing peeling.
2Reliability
If multiple coating layers are used to improve performance, then the sliding properties are enhanced, but the manufacturing time and costs increase
Solution Approach 1:
The invention reduces the number of coating layers by removing unnecessary intermediate alloy layers. This simplification directly decreases the film formation time and manufacturing complexity while maintaining adequate sliding properties through the essential chromium and diamond-like carbon layers.
Solution Approach 2:
The patent optimizes the parameters of the remaining coating layers (chromium and diamond-like carbon) to achieve the desired sliding performance with fewer layers. By adjusting thickness, composition, and deposition conditions of these two layers, the patent maintains functional performance while reducing manufacturing time.
3Strength
If tungsten is included in the coating layers to improve hardness, then the abrasion resistance is enhanced, but the tungsten is easily oxidized by acidic substances and reduced by alkaline substances leading to peeling
Solution Approach 1:
The invention extracts tungsten from the coating structure entirely, eliminating its chemical instability issues. The patent achieves adequate abrasion resistance through the diamond-like carbon layer without incorporating tungsten, thereby avoiding oxidation by acidic substances and reduction by alkaline substances that cause peeling.
Solution Approach 2:
The patent replaces expensive and chemically unstable tungsten-containing alloy layers with a more stable diamond-like carbon coating. While diamond-like carbon provides sufficient abrasion resistance, it offers superior chemical stability against both acidic and alkaline environments, eliminating the peeling problem associated with tungsten.
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 enhances the peeling strength and abrasion resistance of the vane, preventing peeling and reducing costs while maintaining excellent performance over a long period.
Implementation Method 1
formed using an ionic vapor deposition method
Data Source
AI summary
A rotary compressor includes a sealed vertical compressor housing, a compressing unit, and a motor. A refrigerant discharging unit is provided at an upper part and a refrigerant intake unit is provided at a lower part side surface in the sealed vertical compressor housing. The compressing unit is disposed on the lower part of the compressor housing, includes an annular cylinder, an end plate including a bearing unit and a discharge valve unit and blocking end portions of the cylinder, an annular piston that engages with an eccentric portion of a rotation axis supported by the bearing unit, revolves along a cylinder inner wall of the cylinder in the cylinder, and forms a cylinder chamber between the cylinder inner wall and the annular piston, and a vane. The motor is disposed on the upper part of the compressor housing, and drives the compressing unit via the rotation axis.