Elastic Coating on Scroll Wrap Portions for Sealing and Wear
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Solution Overview
Problem
Existing scroll type fluid machines face challenges in maintaining a tightly sealed enclosed space between the fixed and orbiting scrolls due to thermal deformation and pressure differences, leading to issues like seizure, galling, wear, and contact damage, and current coating methods struggle with precise control of coating thickness and even application.
Innovation Solution
An elastic coating is formed using a solution containing 10-20% epoxy resin and 25-40% MoS2, which is applied at a thickness allowing elastic deformation, preventing plastic deformation and ensuring adhesiveness, with a method that adjusts rotation speed and nozzle movement to achieve even coating thickness across the wrap portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating is applied to the wrap side face to secure a minute gap and prevent contact damage, then reliability is improved, but manufacturing precision deteriorates due to difficulty in controlling coating thickness uniformly
Solution Approach 1:
The patent changes the physical-chemical parameters of the coating material by using a two-component system (epoxy resin + solid lubricant) instead of conventional single-component coatings. This allows the coating to achieve both adequate thickness and uniform application by controlling the chemical composition ratios rather than relying solely on precise thickness control during application.
Solution Approach 2:
The patent applies a composite coating material consisting of epoxy resin (for adhesion and structural integrity) and solid lubricant particles (for lubrication and wear resistance). This composite structure enables the coating to fulfill multiple functions simultaneously while being applied at a broader thickness range, reducing the need for precise thickness control.
2Productivity
If the wrap portions are sealed tightly to secure compression and expansion performance, then productivity is improved, but reliability deteriorates due to thermal deformation and pressure differences causing contact damage
Solution Approach 1:
The patent applies a coating layer beforehand to the wrap side faces to create a protective cushion that absorbs thermal deformation and pressure-induced stresses. This pre-applied protective layer prevents direct metal-to-metal contact under operating conditions, thereby preventing seizure, galling, wear, and contact damage while maintaining sealing performance.
Solution Approach 2:
The coating layer acts as an intermediary substance between the opposing wrap portions, mediating the interaction under thermal and pressure loads. This intermediate layer allows the wrap portions to maintain tight sealing for productivity while preventing direct contact that would cause reliability issues.
3Reliability
If a coating film with lubricating and wear-resistant properties is applied to form an optimum gap, then reliability is improved, but device complexity increases due to the need for precise coating thickness control and surplus removal
Solution Approach 1:
The patent employs a self-service coating application method where the two-component coating material (epoxy resin + solid lubricant) automatically achieves uniform thickness and proper distribution through its chemical formulation and application mechanism. The coating self-regulates its thickness within an acceptable range without requiring complex control systems or post-application surplus removal processes, thereby reducing device complexity.
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 elastic coating effectively seals the enclosed space, prevents damage, and maintains lubricating and sliding properties, ensuring reliable operation without the need for precise coating thickness control, and can be applied uniformly across the wrap portion.
Implementation Method 1
a coating thickness enabling elastic deformation is formed on the wrap portion side face... the coating thickness enabling elastic deformation refers to a coating thickness at which the elastic coating can adhere tightly to the wrap portion side face in a state of constant elastic deformation during an operation
Implementation Method 2
a powdered solid lubricant having MoS2 as a main component... provides the coating film with an impact absorbing function... maintaining lubricating and sliding properties
Data Source
Figure 1
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Figure 4~6
AI summary
A coating solution that contains 10 to 20% by weight of epoxy resin serving as a thermosetting resin, 20 to 30% by weight of MoS2, and 5 to 10% by weight of graphite, with a remainder thereof constituted by an organic solvent, is sprayed onto a wrap portion side face 24a of an orbiting scroll 20 from a spray nozzle 52. While spraying the coating solution, the orbiting scroll 20 is rotated on a rotating table 32 and the spray nozzle 52 is moved along a rectilinear movement path L toward a radial direction outer side of the orbiting scroll 20 while maintaining an attitude thereof from the start of the spraying process. After applying the coating solution, the coating solution is dried by baking, whereupon a break-in operation is performed. As a result, an elastic coating 28 is formed at a coating thickness that enables elastic deformation in accordance with a clearance between the wrap portion side faces.