Scroll Compressor Oil Groove Asymmetric Chamfer Design
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Solution Overview
Problem
In scroll compressors, the formation of an oil groove in the thrust sliding surface between a fixed and an orbiting scroll often results in inadequate lubrication and sealing due to high-pressure oil not effectively spreading to the outer peripheral portion, leading to refrigerant leakage and potential overturn of the orbiting scroll when the back-pressure space is at intermediate or high pressure.
Innovation Solution
The oil groove is designed with an outer peripheral chamfer larger than the inner peripheral chamfer, allowing high-pressure oil to easily flow into the outer peripheral portion, reducing pressure differences and minimizing oil flow into the compression chamber, thus ensuring effective lubrication and sealing across the thrust sliding surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-pressure oil is supplied to the oil groove in the thrust sliding surface, then lubrication and sealing are improved, but when the back-pressure space is at intermediate or high pressure, oil does not spread to the outer peripheral portion, causing sealing failure and potential overturn
Solution Approach 1:
The invention applies asymmetry by making the outer peripheral chamfer larger than the inner peripheral chamfer in the oil groove. This asymmetric design creates different flow characteristics at the inner and outer periphery of the oil groove, enabling oil to effectively reach the outer peripheral portion even when the back-pressure space is at intermediate or high pressure, thereby preventing sealing failure and overturn.
2Force
If the back-pressure space is at intermediate or high pressure, then pressing force is maintained, but oil flow into the compression chamber increases and oil does not reach the outer peripheral portion
Solution Approach 1:
The invention applies local quality by creating different chamfer sizes at different locations of the oil groove. The larger outer peripheral chamfer is specifically designed to control oil flow at the outer periphery, reducing oil loss to the compression chamber while maintaining adequate oil supply for sealing and lubrication under high back-pressure conditions.
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 performance and reduces the likelihood of orbiting scroll overturn, maintaining pressure in the back-pressure space and improving compressor efficiency and reliability by ensuring oil spreads evenly to the outer peripheral portion of the oil groove.
Implementation Method 1
high-pressure oil is supplied to the back surface of an orbiting scroll so that a pressing force toward a fixed scroll is applied to the orbiting scroll
Implementation Method 2
The high-pressure oil supplied to the oil groove is distributed over the thrust sliding surface to be used for sealing as well as to lubricate the thrust sliding surface
Implementation Method 3
The oil groove is designed with an outer peripheral chamfer larger than the inner peripheral chamfer, allowing high-pressure oil to easily flow into the outer peripheral portion, reducing pressure differences
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
In a scroll compressor in which pressing force of an orbiting scroll against a fixed scroll is adjusted with an oil groove (81) formed in a thrust sliding surface between an movable end plate (51) and a fixed end plate, at least in a region serving as a suction space (50 L) of fluid in an outer peripheral portion of a compression chamber (50), an outer seal length (L1) from an outer peripheral edge of the oil groove (81) formed in the thrust sliding surface (80) to an outer edge (86) of the movable end plate (51) is smaller than an inner seal length (L2) from an inner peripheral edge of the oil groove (81) to a peripheral edge of the compression chamber (50) so as to reduce occurrence of a sealing failure and a lubrication failure, overturn of the orbiting scroll (5), and performance degradation of the compressor.