Scroll Compressor Back Pressure Plate Sealing
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Solution Overview
Problem
Conventional upper back pressure type scroll compressors face challenges in preventing refrigerant leakage and enhancing lubricity while minimizing friction, leading to issues with noise and vibration due to the restrictive positioning of bypass holes and increased production costs from complex assembly processes.
Innovation Solution
The design incorporates a back pressure plate with integrally formed bypass holes and a bypass valve that can be positioned arbitrarily, allowing for effective sealing and reduced assembly complexity by integrating the hub member and floating plate, facilitating the formation of bypass holes at any location on the non-orbital scroll.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the end of the wrap portion and the surface of the plate portion are adhered to each other with excessive force, then leakage of refrigerant is prevented, but friction between parts increases resulting in increased noise and abrasion
Solution Approach 1:
A back pressure chamber is introduced as an intermediary mechanism between the wrap portion and plate portion. The chamber communicates with intermediate pressure compression chambers and applies controlled back pressure to maintain sealing force while preventing excessive adhesion force that causes friction, noise, and abrasion.
2Ease of manufacture
If the back pressure chamber is positioned on the lower surface of the first scroll, then the structure is simple and bypass holes are easily formed, but the back pressure chamber form and position change due to orbital motion causing the first scroll to tilt and increasing vibration and noise
Solution Approach 1:
Instead of positioning the back pressure chamber on the lower surface of the first scroll (orbital scroll), the invention inverts the approach by positioning it on the upper surface of the second scroll (non-orbital scroll). This inversion stabilizes the chamber form and position, preventing scroll tilting and reducing vibration and noise, while still maintaining ease of manufacture.
3Reliability
If the back pressure chamber is positioned on the upper surface of the second scroll, then the probability of the second scroll tilting is low and sealing is excellent, but the structure becomes complicated
Solution Approach 1:
The back pressure chamber structure is merged with the discharge cover and non-orbital scroll components. The discharge cover serves dual functions as both a cover and as a structural element that forms part of the back pressure chamber, reducing the number of separate components and simplifying the overall structure while maintaining excellent sealing efficiency.
4Device complexity
If bypass holes are restrictively positioned, then the back pressure chamber structure is simplified, but the positioning flexibility is reduced and production costs increase due to complex assembly processes
Solution Approach 1:
The back pressure chamber is designed with universal adaptability to accommodate bypass holes at various positions. The chamber structure serves multiple functions: maintaining back pressure, sealing refrigerant, and providing flexible mounting positions for bypass holes. This multi-functionality allows bypass holes to be positioned optimally for different assembly configurations without increasing structural 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
This configuration enhances the sealing efficiency between the back pressure chamber and discharge opening, reduces production costs, and minimizes overload issues by allowing flexible positioning of bypass holes, thereby improving the performance and reliability of the scroll compressor.
Implementation Method 1
a back pressure chamber having an intermediate pressure between a discharge pressure and a suction pressure may be formed on or at a rear surface of the first scroll or the second scroll
Implementation Method 2
a first or orbital scroll having a spiral wrap, and a second or non-orbital scroll having a spiral wrap, the first scroll performing an orbital motion with respect to the second scroll
Implementation Method 3
a seal member may be provided between the back pressure chamber and the discharge opening
Data Source
AI summary
A scroll compressor is provided that may include a casing; a discharge cover fixed to an inner space of the casing, that divides the inner space of the case into a suction space and a discharge space; a main frame in the casing, and spaced from the discharge cover; an orbital scroll that performs an orbital motion on the main frame; a non-orbital scroll coupled to the main frame so as to be movable up and down with respect to the orbital scroll, that forms a suction chamber, an intermediate pressure chamber, and a discharge chamber together with the orbital scroll; and a back pressure plate provided between the discharge cover and the non-orbital scroll, that forms a back pressure chamber that communicates with the intermediate pressure chamber. With such a configuration, a bypass valve may be easily installed, and application of an overload minimized.