Foil Bearing Coating Composition for Durable Turbo Fluid Machines
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Solution Overview
Problem
The existing turbo fluid machines face challenges in increasing the durability of the coating layer on the bearing surface of the foil bearing, which affects the life of the foil bearing.
Innovation Solution
A turbo fluid machine is designed with a coating layer on at least one of the bearing-contact surface or the bearing surface, comprising polyamide-imide as a binder resin and molybdenum disulfide as a solid lubricant, with a mass ratio of molybdenum disulfide to polyamide-imide being 0.42 or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polyamide-imide is used as a coating material to increase hardness and wear resistance, then the coating layer becomes more wear-resistant, but the durability of the coating layer on the bearing surface does not increase as expected
Solution Approach 1:
The patent applies composite materials by combining polyamide-imide (binder resin) with molybdenum disulfide (solid lubricant) in a specific mass ratio of 0.06 to 0.6. This composite coating structure integrates the hardness and adhesion benefits of polyamide-imide with the low-friction properties of molybdenum disulfide, resolving the contradiction between wear resistance and durability by creating a synergistic material system that addresses both requirements simultaneously.
Solution Approach 2:
The patent employs parameter changes by optimizing the mass ratio of molybdenum disulfide to polyamide-imide within the range of 0.06 to 0.6. This specific parameter range ensures that the coating maintains adequate adhesion and structural integrity from the polyamide-imide while incorporating sufficient molybdenum disulfide to provide durable low-friction properties, thereby increasing the durability of the coating layer on the bearing surface.
2Ease of operation
If the bearing-contact surface slides on the bearing surface at low speed rotation, then the rotating member is supported by contact support, but damage such as seizure occurs to the sliding surface
Solution Approach 1:
The patent introduces molybdenum disulfide as an intermediary substance within the coating layer that acts as a solid lubricant between the bearing-contact surface and the bearing surface. This intermediary material reduces direct metal-to-metal contact and minimizes friction and wear during low-speed operation, preventing seizure and damage to the sliding surfaces while maintaining the necessary contact support functionality.
Solution Approach 2:
The patent modifies the surface properties of the bearing interface by applying a coating layer with specific compositional parameters (polyamide-imide to molybdenum disulfide mass ratio of 0.06 to 0.6). This parameter change transforms the sliding surface characteristics, reducing the coefficient of friction and preventing seizure while maintaining adequate load-bearing capability during low-speed rotation.
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 proposed solution effectively increases the durability of the coating layer, thereby enhancing the life of the foil bearing and reducing wear and tear, leading to improved performance and reliability of the turbo fluid machine.
Implementation Method 1
molybdenum disulfide serving as a solid lubricant
Data Source
AI summary
A turbo fluid machine includes a rotating member having a bearing-contact surface; an operating part configured to rotate together with the rotating member to compress and discharge a fluid; a housing accommodating the rotating member and the operating part; and a foil bearing having a bearing surface that faces the bearing-contact surface and supporting the rotating member such that the rotating member is rotatable relative to the housing. At least one of the bearing-contact surface or the bearing surface has thereon a coating layer. The coating layer comprises polyamide-imide serving as a binder resin and molybdenum disulfide serving as a solid lubricant. A mass ratio of molybdenum disulfide to polyamide-imide is 0.42 or more.