Scroll Compressor Sliding Surface Design for Leakage Reduction
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Solution Overview
Problem
Conventional scroll compressors face issues with high sliding loss and refrigerant leakage due to excessive contact area between the sliding surfaces of the fixed and orbiting scrolls, which can lead to increased swinging of the orbiting scroll and further leakage, despite attempts to reduce these losses through backpressure introduction.
Innovation Solution
The design incorporates depression sections and elevated flange sections on the sliding surfaces of at least one of the scrolls, which are formed outside a referential perfect circle, to reduce the contact area and enhance the sealing performance, thereby minimizing sliding loss and refrigerant leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact area between sliding surfaces is increased to reduce refrigerant leakage, then sealing performance is improved, but sliding loss increases
Solution Approach 1:
The invention applies different surface characteristics to different regions of the sliding surface. The circumferential end portion has a different surface quality (depression section) compared to the central portion, creating local variations in pressing force and sealing performance. This allows optimal sealing where needed while minimizing friction in other areas.
Solution Approach 2:
The sliding surface is divided into distinct functional zones: a depression section at the circumferential end and an elevated section in the central region. This segmentation allows each zone to perform its specific function - the depression section provides enhanced sealing, while the elevated section reduces contact area and sliding loss.
2Reliability
If backpressure is increased to press the orbiting scroll against the fixed scroll, then refrigerant leakage is reduced, but sliding friction increases
Solution Approach 1:
The depression section creates a localized region of increased backpressure effect at the circumferential end of the sliding surface. This concentrates the sealing force where it is most needed (at the seal length termination point) while avoiding increased friction across the entire sliding surface.
3Reliability
If the orbiting scroll is pressed against the fixed scroll to cancel separating force, then sealing is improved, but the orbiting scroll swinging increases
Solution Approach 1:
The depression section at the circumferential end provides localized pressing force that enhances sealing without creating excessive overall pressing force that would cause swinging. The elevated central portion maintains stability by providing a balanced contact area.
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 configuration effectively reduces sliding loss and refrigerant leakage in the entire compression chamber by preventing the orbiting scroll from swinging and maintaining efficient sealing, even in regions with short seal lengths.
Implementation Method 1
a backpressure chamber is formed, on the back of the sliding plate of the orbiting scroll, to hold backpressure to press the orbiting scroll against the fixed scroll. The backpressure is pressure within the backpressure chamber and takes an intermediate value between the discharge pressure and the suction pressure.
Implementation Method 2
the area of contact between the sliding surface of the fixed scroll and the sliding surface of the orbiting scroll is large, and the sliding loss is still large. This configuration effectively reduces sliding loss and refrigerant leakage in the entire compression chamber by preventing the orbiting scroll from swinging and maintaining efficient sealing.
Data Source
AI summary
A scroll compressor includes a fixed scroll, an orbiting scroll, a suction section, a discharge section, and an electric motor. A sliding surface of a scroll is formed outside a wrap with a depression section depressed with respect to a sliding surface and a flange section elevated with respect to the depression section. The flange section is a remaining region in a protruding region disposed outside a referential perfect circle, the remaining region being other than a region continuing to an end of an involute curve of a scroll formed with the flange section, the referential perfect circle having a radius set to a distance between the center of the scroll formed with the flange section and the end of the involute curve. The scroll compressor enhances reduction of the sliding loss with a simple structure and reduction of the refrigerant leakage loss in the entire compression chambers.