Scroll Compressor Oldham Ring Trough Design for Wear Reduction
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Solution Overview
Problem
The existing scroll compressor designs suffer from stress concentration and wear of the Oldham ring due to repeated collisions, leading to increased maintenance costs and reduced efficiency, as the Oldham ring is made of aluminum alloys while the scrolls are made of harder materials like stainless steel.
Innovation Solution
The introduction of an Oldham ring with first and second troughs that house protrusions and blocks respectively, reducing stress on the ring and enhancing its structural strength, allowing for reduced wear and increased reliability by restricting the rotation of the orbiting scroll.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the Oldham ring is made of aluminum alloy to reduce weight, then the weight of the Oldham ring is reduced, but the wear resistance deteriorates because the hardness is lower than the scrolls
Solution Approach 1:
The Oldham ring employs a composite structure combining aluminum alloy (lightweight) with embedded hard materials such as ceramic or steel inserts at the key slot regions. This composite approach maintains the overall weight advantage while providing localized wear resistance where contact with scroll keys occurs, directly resolving the contradiction between lightweight design and wear resistance.
Solution Approach 2:
The aluminum alloy Oldham ring features localized reinforcement through embedded hard materials or surface hardening treatments specifically at the key slot contact areas. This local quality enhancement provides high wear resistance precisely where needed (at the interfaces with scroll keys) while maintaining the lightweight aluminum alloy construction in non-contact regions, thus resolving the weight versus wear resistance contradiction.
2Reliability
If the protruding key of the Oldham ring is made to fit tightly in the key slots to prevent scroll rotation, then the rotation prevention effectiveness is improved, but the stress concentration increases leading to repeated collisions and wear
Solution Approach 1:
The key slots in the Oldham ring are designed with rounded bottom corners and increased width at the base, creating a cushioning effect that absorbs impact stresses before they reach the critical stress concentration points. This beforehand cushioning design allows tight fitting for rotation prevention while reducing the severity of collision stresses, thereby resolving the contradiction between rotation prevention effectiveness and stress resistance.
Solution Approach 2:
The key slot structure is segmented into multiple zones: an entry section, a transition section with rounded corners, and a base section with increased width. This segmentation allows the key to fit tightly in the rotation-prevention-critical regions while providing stress-dissipating geometry in the transition zones, thus resolving the contradiction between rotation prevention and stress resistance.
3Ease of manufacture
If the Oldham ring structure is simplified to reduce manufacturing complexity, then the ease of manufacture is improved, but the structural strength decreases leading to increased wear
Solution Approach 1:
The Oldham ring design optimizes geometric parameters such as key slot dimensions, ring thickness, and reinforcement placement to achieve the required structural strength. By carefully selecting and adjusting these parameters, the ring maintains high strength-to-manufacturing-complexity ratio, allowing straightforward aluminum alloy casting or machining while incorporating strength-enhancing features like optimized key slot geometry and strategic reinforcement elements.
Data Source
AI summary
A scroll-rotation prevention assembly of a scroll compressor includes a fixed scroll, an orbiting scroll and an Oldham ring. The fixed scroll is positioned in the compressor and has a body. Two blocks extend from the periphery of the body. The orbiting scroll is disposed to correspond to the fixed scroll and has a main body. Two protrusions extend from the periphery of the main body. The Oldham ring is sandwiched between the body of the fixed scroll and the main body of the orbiting scroll. The Oldham ring has a first surface provided with a pair of first troughs and a second surface opposite to the first surface. The second surface is provided with a pair of second troughs. Each protrusion is slidably connected in the first troughs. Each block is slidably connected in the second troughs. Thus, the wear of the Oldham ring can be reduced.