Refrigerant compressor and refrigeration device including refrigerant compressor
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Solution Overview
Problem
Conventional refrigerant compressors face issues with abrasion resistance due to the degradation of phosphate coating films when using lubricating oils with lower viscosity or shorter slide lengths, leading to increased friction coefficients and abnormal abrasion, particularly in regions between the crankshaft and bearing sections.
Innovation Solution
A refrigerant compressor design featuring an oxide coating film on iron-based materials, with a diiron trioxide (Fe2O3) layer near the surface and a silicon-rich layer closer to the base material, improving adhesivity and conformability, and reducing sliding losses, even with low-viscosity lubricating oils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a phosphate coating film is formed on the slide surface to prevent abrasion and improve initial conformability, then the abrasion resistance is improved, but the coating film degrades when using lubricating oils with lower viscosity or shorter slide lengths, leading to reduced reliability
Solution Approach 1:
The patent applies a multi-layer oxide coating film composed of different materials: an inner layer of Fe-O-Si oxide containing silicon (adhesion promoter), a middle layer of Fe-O oxide (protective barrier), and an outer layer of Fe2O3 (abrasion resistance). This composite structure combines the benefits of each material to achieve both adhesion to the base metal and resistance to degradation from low-viscosity lubricating oils, resolving the contradiction between initial conformability and long-term stability.
Solution Approach 2:
The coating film is designed with different layers having different compositions and functions at different depths. The inner layer near the base material contains silicon for adhesion, the middle layer provides protective barriers, and the outer layer provides abrasion resistance. This local differentiation of material properties allows each layer to perform its specific function optimally, maintaining overall coating stability under varying operating conditions.
2Loss of energy
If lubricating oil with lower viscosity is used to reduce friction and improve efficiency, then the energy efficiency is improved, but the phosphate coating film is abraded or worn out at earlier time, reducing reliability
Solution Approach 1:
The multi-layer oxide coating film with Fe-O-Si inner layer, Fe-O middle layer, and Fe2O3 outer layer provides enhanced durability that can withstand the harsher conditions created by low-viscosity lubricating oils. The silicon-containing inner layer strongly adheres to the base material, preventing coating delamination, while the Fe2O3 outer layer resists abrasion from the thinner oil film, enabling the system to use low-viscosity oils without sacrificing reliability.
Solution Approach 2:
The patent changes the chemical composition parameters of the coating film by incorporating silicon in the inner layer and forming specific oxide phases (Fe-O-Si, Fe-O, Fe2O3) in different layers. This parameter modification creates a coating with enhanced chemical stability and abrasion resistance that can maintain its protective function even when exposed to low-viscosity lubricating oils that would otherwise cause rapid degradation.
3Loss of energy
If the slide length of slide sections is designed to be shorter to improve efficiency, then the energy efficiency is improved, but the phosphate coating film wears out at earlier time due to reduced lubrication coverage, reducing reliability
Solution Approach 1:
The multi-layer oxide coating film provides enhanced protection for shorter slide sections where lubrication coverage is reduced. The Fe-O-Si inner layer ensures strong adhesion to prevent coating failure, while the Fe2O3 outer layer provides abrasion resistance to compensate for the reduced lubricating film thickness associated with shorter slide lengths, maintaining reliability despite reduced lubrication coverage.
Solution Approach 2:
The coating structure is optimized for the specific conditions of shorter slide sections by concentrating adhesion-promoting silicon in the inner layer and abrasion-resistant Fe2O3 in the outer layer. This local quality differentiation ensures that the coating can withstand the increased stress and reduced lubrication coverage inherent in shorter slide length designs.
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 oxide coating film enhances abrasion resistance, reliability, and efficiency by reducing sliding losses and maintaining performance under harsh conditions, including high-temperature and high-load operations.
Implementation Method 1
the lubricating oil 2 is fed to the slide sections by the oil feeding pump 10, and lubricates each of the slide sections
Data Source
Figure 1
Figure 2A~2D
Figure 3
AI summary
A refrigerant compressor reserves lubricating oil with a viscosity of VG2 to VG100 in a sealed container, and accommodates therein an electric component and a compression component which is driven by the electric component and compresses a refrigerant. The compression component includes at least one slide member comprising a base material 171 made of an iron-based material and an oxide coating film 170 provided on a surface of the base material 171. The oxide coating film 170 includes: a portion containing diiron trioxide (Fe2O3), in a region which is closer to an outermost surface of the oxide coating film; and a silicon containing portion containing silicon (Si) which is more in quantity than silicon (Si) of the base material 171, in a region which is closer to the base material 171.