Oldham Coupling Caps for Scroll Compressor Wear Reduction
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Solution Overview
Problem
Conventional Oldham couplings in compressors experience excessive wear due to the use of certain working fluids like refrigerants, which reduce the effectiveness of lubricants and lead to friction-related issues, affecting the reliability and efficiency of the compressor's operation.
Innovation Solution
The design incorporates an Oldham coupling with keys and caps made from different materials, where the caps are formed from high-lubricity materials like polymers or metals, attached to posts made from a first material, to isolate the posts from friction and reduce wear, thereby extending the coupling's lifespan and improving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional Oldham coupling keys are used without caps, then the structure is simple and manufacturing is easy, but excessive wear occurs and lubricant effectiveness is reduced
Solution Approach 1:
The Oldham coupling keys are constructed using composite materials: a metal post provides structural strength while a polymer cap provides low-friction surfaces. This composite structure resolves the contradiction by combining the advantages of different materials to achieve both wear resistance and structural integrity without excessive complexity
Solution Approach 2:
The polymer cap acts as an intermediary between the metal post and the slot contact surfaces. It mediates the interaction by providing a low-friction interface that reduces wear and maintains lubricant effectiveness, while the metal post provides the necessary structural support
2Strength
If metal keys are used in Oldham coupling, then structural strength is sufficient, but friction and wear increase reducing component life
Solution Approach 1:
The key is designed as a composite structure with a metal post for strength and a polymer cap for reduced friction and wear. This allows the key to maintain sufficient structural strength while significantly extending service life through the low-friction polymer interface
Solution Approach 2:
Different parts of the key have different material properties optimized for their specific functions: the metal post provides localized structural strength where needed, while the polymer cap provides localized low-friction surfaces at the contact interfaces with the slots
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
This design reduces wear and enhances the operational efficiency and longevity of the Oldham coupling, particularly in compressors using refrigerants like propane and carbon dioxide, by minimizing friction and maintaining the effectiveness of lubricants.
Implementation Method 1
The caps may be formed from a second material (i.e., a material that is different from the first material) such as a polymer or metal having low-friction surfaces
Data Source
AI summary
A compressor may include a non-orbiting scroll, an orbiting scroll, a driveshaft and an Oldham coupling. The orbiting scroll meshingly engages the non-orbiting scroll. The driveshaft includes a crankpin engaging the orbiting scroll and driving the orbiting scroll in an orbital path relative to the non-orbiting scroll. The Oldham coupling may include an annular body and a plurality of first keys extending from the annular body and slidably received in slots formed in the orbiting scroll. Each of the first keys may include a first post and a first cap attached to the first post. The first posts may be integrally formed with the annular body from a first material. The first caps may be formed from a second material.