Scroll Compressor Back Pressure Circulation for Oil Supply
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Solution Overview
Problem
Existing scroll compressors face issues with pressure imbalances in the back pressure chamber leading to performance degradation or structural abrasion, and existing solutions increase compressor size or lead to insufficient oil supply.
Innovation Solution
A back pressure circulation structure that directly emits oil and refrigerant from the back pressure chamber to the scroll, utilizing a simplified recovery flow path and decompression mechanisms to maintain optimal pressure and ensure efficient oil circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate decompression device is provided on the motor housing side, then decompression function is improved, but the entire size increases and packaging becomes disadvantageous
Solution Approach 1:
The decompression function is merged with the existing motor housing structure by utilizing the hollow space of the rotating shaft and the gap between the bearing and shaft. This integration eliminates the need for a separate decompression device, achieving decompression functionality while avoiding additional packaging volume.
Solution Approach 2:
The rotating shaft structure serves multiple functions: it transmits rotational force from the motor and simultaneously provides a hollow passage for refrigerant decompression. The gap between the bearing and shaft, which is necessary for mechanical operation, is also utilized as a decompression pathway, making the system multi-functional without increasing size.
2Reliability
If the path through which refrigerant and oil flow is increased, then decompression is improved, but oil supply becomes insufficient
Solution Approach 1:
The decompression process is performed preliminarily within the motor housing before refrigerant and oil are discharged to the condenser. By decompressing the refrigerant-oil mixture in advance through the rotating shaft hollow space, the system ensures that oil remains properly mixed with refrigerant and is supplied efficiently to the evaporator, preventing oil starvation.
Solution Approach 2:
The rotating shaft hollow space acts as an intermediary decompression chamber that allows controlled expansion of the refrigerant-oil mixture. This intermediate decompression step prevents excessive flow path length while ensuring proper phase separation and oil return, maintaining both decompression efficiency and oil supply adequacy.
3Stress or pressure
If back pressure chamber pressure is excessively high, then back pressure maintenance is improved, but abrasion increases causing structural problems
Solution Approach 1:
The back pressure chamber pressure is dynamically regulated through the decompression mechanism. By allowing controlled decompression through the rotating shaft hollow space and bearing gap, the system maintains back pressure within an optimal range rather than allowing it to become excessively high, thereby reducing abrasion on moving parts while still preventing refrigerant leakage.
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
The solution reduces compressor size and ensures reliable oil supply, improving durability and performance by maintaining balanced pressure and filtering foreign matter, thus enhancing the overall efficiency of the scroll compressor.
Implementation Method 1
decompression is essentially required before the pressure relief
Implementation Method 2
refrigerant and oil discharged from the back pressure chamber are directly emitted toward the scroll
Data Source
AI summary
A scroll compressor for an air conditioning system of a vehicle includes a back pressure circulation structure. Oil and refrigerant discharged from a back pressure chamber to maintain back pressure are directly emitted toward a scroll to ensure circulation of refrigerant. The size of a package incorporating the scroll compressor is reduced through structural simplification.