Grooved Thrust Bearing for Scroll Compressor Lubrication
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Solution Overview
Problem
Scroll compressors face challenges in forming a consistent oil film on sliding surfaces due to high pressure and large pressure-receiving areas, leading to seizure issues, especially when lubricating oil supply is suspended, and existing solutions either require complex control operations or fail to maintain effective lubrication under mixed or boundary lubrication conditions.
Innovation Solution
A scroll compressor design featuring a thrust bearing with a network of grooves on the sliding surface, forming insular pressure receiving portions that communicate with each other, allowing for lubricating oil to be introduced from all directions and maintaining an oil film even without continuous oil supply, and utilizing a donut-shaped configuration to prevent oil displacement during orbiting motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a thrust bearing with planar flat plate sliding surfaces is used, then the structure is simple, but the oil film becomes inconsistent under excessive load resulting in seizure
Solution Approach 1:
The sliding surface is segmented into multiple independent pressure-receiving portions (islands) separated by grooves. Each pressure-receiving portion can independently maintain oil film pressure, preventing oil from escaping laterally under load. This segmentation allows the bearing to handle excessive loads while maintaining consistent oil film distribution across the sliding surface.
Solution Approach 2:
Different regions of the sliding surface are given different functions: pressure-receiving portions are designed to maintain high oil pressure for load support, while grooves are designed to supply and distribute oil to these pressure zones. This local differentiation of functionality enables the bearing to maintain reliable lubrication under varying load conditions without increasing overall structural complexity.
2Quantity of substance
If minuscule oil pools with holes are formed on the sliding surface, then lubricating oil is held by adsorption, but the amount of oil that can be held is limited and negative pressure generates seizure
Solution Approach 1:
Instead of using numerous minuscule isolated oil pools, the invention uses a segmented design with fewer but larger pressure-receiving portions connected by grooves. This allows oil to be distributed across a larger total area while maintaining the benefit of localized oil retention. The grooves act as oil supply channels that continuously replenish oil to pressure zones, preventing oil depletion and negative pressure generation.
Solution Approach 2:
The grooves serve as intermediary channels that connect the oil supply source to the pressure-receiving portions. These grooves facilitate continuous oil flow and pressure equalization between different regions, preventing the generation of negative pressure that would otherwise occur in isolated minuscule oil pools when oil supply is interrupted.
3Area of stationary object
If the thrust bearing is arranged over the whole back surface of the movable scroll, then coverage is maximized, but minuscule oil pools are displaced out of the mating side during orbiting motion reducing lubrication area
Solution Approach 1:
The thrust bearing is segmented into pressure-receiving portions and grooves where the grooves form a continuous or interconnected network. This segmentation allows the grooves to act as flexible oil supply channels that can accommodate the orbital motion of the movable scroll. The pressure-receiving portions remain in contact with the mating surface while the groove network maintains oil supply pathways, preventing displacement of lubrication areas during orbiting motion.
4Force
If a back pressure mechanism is used to reduce load on sliding surfaces, then the load is reduced, but complicated control operation and increased cost are required
Solution Approach 1:
The thrust bearing is segmented into pressure-receiving portions that are strategically positioned and sized to naturally distribute and reduce the thrust load through increased contact area. The grooves between pressure portions further distribute the load by providing additional oil film support zones. This passive load distribution through geometric segmentation eliminates the need for active back pressure control mechanisms, reducing device complexity and cost while maintaining reduced load on any single sliding surface.
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 design effectively suppresses wear on sliding surfaces, prevents seizure, and establishes hydrodynamic lubrication, ensuring the compressor operates efficiently and reliably under varying load conditions without complex control operations or increased costs.
Implementation Method 1
the lubricating oil is held by adsorption on the wall surface of the minuscule oil pools
Implementation Method 2
establishes hydrodynamic lubrication
Data Source
AI summary
A scroll compressor is disclosed. A plurality of grooves (85) communicating with each other are formed on a sliding surface of a thrust bearing (53) subjected to the axial force received by a movable scroll (32). The areas surrounded by the plurality of the grooves (85) make up a plurality of insular pressure receiving portions (83) independent of each other. The pressure receiving portions (83) represent at least one half of the area of the sliding surface.