Oxide-Coated Slide Member for Low-Viscosity Compressor Lubrication
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Solution Overview
Problem
Refrigerant compressors face challenges in effectively suppressing metal surface contact and improving lubricating oil retention, especially with lower viscosity oils, leading to increased load on sliding surfaces, abrasion of phosphate coating films, and reduced efficiency and reliability.
Innovation Solution
A slide member with an iron-based material and a three-layer oxide coating film structure (Fe2O3, Fe3O4, FeO) is used, along with dense oxide coating films having minute concave/convex portions, to enhance abrasion resistance and lubricating oil retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a phosphate coating film is used to reduce metal surface contact, then smooth sliding is improved, but the coating film degrades under refrigerant gas bubbles and high load conditions
Solution Approach 1:
The patent applies composite materials by creating a multi-layer coating structure consisting of a base coat layer and a top coat layer with different functions. The base coat provides adhesion and corrosion resistance, while the top coat provides hardiness and abrasion resistance. This composite structure resolves the contradiction by combining materials with complementary properties to achieve both smooth sliding and durability under high load conditions.
Solution Approach 2:
The patent changes the physical and chemical parameters of the coating by controlling the oxidation potential, pH value, and composition ratios during the coating formation process. By adjusting these parameters, the coating achieves optimal adhesion strength, hardness, and resistance to degradation from refrigerant gas bubbles, thereby improving both smooth sliding and coating durability.
2Use of energy by moving object
If lower viscosity lubricating oil is used to improve compressor efficiency, then energy efficiency is improved, but lubricating oil retention capability deteriorates
Solution Approach 1:
The patent utilizes porous materials by creating a coating structure with controlled porosity that can absorb and retain lubricating oil. The porous structure acts as an oil reservoir, ensuring continuous lubrication even when using lower viscosity oils that would otherwise be easily depleted from the sliding surfaces, thus maintaining both efficiency and retention capability.
Solution Approach 2:
The patent applies local quality by creating regions with different properties within the coating structure. The coating has varying porosity, hardness, and chemical composition at different depths and locations, with oil-retention optimized regions near the sliding surface and structurally stable regions deeper in the coating, allowing the system to maintain low viscosity operation while ensuring adequate lubrication retention.
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 improves abrasion resistance, reliability, and efficiency of the refrigerant compressor by effectively preventing metal surface contact and maintaining lubrication, even with low viscosity oils, thereby reducing sliding losses and enhancing compression performance.
Implementation Method 1
dense oxide coating films having minute concave/convex portions with a height difference which falls within a range of 0.01 μm to 0.1 μm
Implementation Method 2
an oxide coating film having a three-layer structure including a first layer comprising Fe2O3, a second layer comprising Fe3O4, and a third layer comprising FeO
Data Source
AI summary
A slide member of the present invention is used in a slide unit which is included in a refrigerant compressor for compressing a refrigerant and provided inside a sealed container which reserves lubricating oil therein. The slide member is provided with an oxide coating film on a surface of a base material. The oxide coating film is configured such that (1) when the base material comprises an iron based material, the oxide coating film has a three-layer structure including a first layer comprising Fe2O3, a second layer comprising Fe3O4, and a third layer comprising FeO in this order from an outermost surface, (2) the oxide coating film has a dense structure having minute concave/convex portions with a height difference which falls within a range of 0.01 μm to 0.1 μm, or (3) when the base material comprises the iron based material, the oxide coating film has a three-layer structure in which the three layers comprise the iron oxides and are different in hardness.