Scroll Compressor Sealing Member Tongue Part Design
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Solution Overview
Problem
Back pressure type scroll compressors using natural refrigerants like CO2 face lower pressure ratios, leading to reduced force pressing the orbiting scroll against the fixed scroll, potentially causing refrigerant leakage and lower compression efficiency.
Innovation Solution
The design incorporates an Oldham's ring and a sealing member with a tongue part to increase the pressure receiving area without enlarging the orbiting scroll's diameter, along with a plate and tongue part configuration to enhance sealing and lubrication, reducing friction and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If CO2 is compressed by the back pressure type scroll compressor, then the pressure ratio is lower than with chlorofluorocarbon refrigerant, but this results in deficiency of pressing force on the orbiting scroll against the fixed scroll
Solution Approach 1:
The invention increases the pressing force not by enlarging the orbiting scroll diameter (horizontal dimension) but by extending the pressure receiving area in the axial dimension through the protruding portion. This allows the back pressure to act over a larger area, generating sufficient pressing force despite the low pressure ratio characteristic of CO2 compression.
2Reliability
If the orbiting scroll diameter is increased to prevent leakage, then sealing performance improves, but the device complexity and size increase
Solution Approach 1:
The invention segments the pressure receiving area into two parts: the original back side surface of the orbiting scroll and the additional area provided by the protruding portion. This segmentation allows the pressure force to be distributed over a larger total area without requiring an increase in the overall scroll diameter, thereby maintaining compact dimensions while improving sealing performance.
3Force
If the pressure receiving area is increased without enlarging the orbiting scroll, then pressing force improves, but the sealing structure becomes more complex
Solution Approach 1:
The protruding portion serves multiple functions simultaneously: it increases the pressure receiving area to enhance pressing force, provides additional sealing surface area to prevent leakage, and maintains compatibility with the existing back pressure chamber structure. This multi-functionality achieves the desired force improvement without proportionally 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 ensures effective sealing and increased compression efficiency even with low pressure ratios, preventing refrigerant leakage and improving the overall performance of the scroll type fluid machine.
Implementation Method 1
a sealing member situated between the fixed member and the orbiting scroll for sealing the back pressure chamber
Implementation Method 2
the sealing member has a tongue part formed to cut off the flow of any fluid from the back pressure chamber to the Oldham's keyway
Implementation Method 3
a back pressure chamber formed between the orbiting scroll and the fixed member
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
To provide a scroll type fluid machine which can ensure that even when the pressure ratio of the pressure P1 of its high pressure chamber (back pressure chamber) to the pressure P2 of its low pressure chamber (P1/P2) is low, its orbiting scroll be pressed against its fixed scroll without having its orbiting scroll increased in diameter to prevent any leakage of a fluid through between the front end face of the wall of its orbiting scroll and the bottom face of the end plate of its fixed scroll. The scroll type fluid machine has an Oldham's keyway (17) formed along the edge of the back side of the orbiting scroll end plate (13a) for holding one end portion of an Oldham's ring (10) slidably, and a sealing member (18) has a tongue part (18a) formed to cut off the flow of any fluid from the back pressure chamber to the Oldham's keyway (17).