Compressor Oil Retainer Prevents Lubricant Leakage
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Solution Overview
Problem
In compressors, lubricating oil easily flows out of the gap between the eccentric portion and the piston, leading to reduced reliability and inefficient lubrication, especially when the sliding surfaces have different axial widths, causing oil shear losses and poor lubrication.
Innovation Solution
A compressor design with an oil retainer that maintains lubricating oil within the gap between the fitted shaft and tubular portions, using an arc-shaped groove with varying depth and an oil retainer that protrudes towards the first sliding surface, preventing refrigerant gas from entering and ensuring consistent lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second sliding surface is made axially narrower to allow lubricating oil flow into the gap, then the lubricating oil can be supplied through the gap to the first sliding surface, but the lubricating oil easily flows out of the gap during drive shaft rotation, making it difficult to supply lubricating oil to the first sliding surface
Solution Approach 1:
The patent applies local quality by creating different axial widths for different sliding surfaces. The first sliding surface has a larger axial width to bear heavier loads, while the second sliding surface has a smaller axial width to facilitate oil flow into the gap. This localized differentiation optimizes both load-bearing capacity and lubrication efficiency at different positions of the same component.
Solution Approach 2:
The oil retainer protrudes into the gap from the first sliding surface side before the drive shaft rotates, creating a preliminary barrier that prevents lubricating oil from flowing out of the gap during rotation. This preliminary positioning of the oil retainer ensures that oil is retained in the gap before the harmful flow-out effect occurs.
2Force
If the first sliding surface is made axially wider to receive heavier load, then the load-bearing capacity is improved, but the lubricating oil easily flows out of the gap, resulting in decrease in reliability
Solution Approach 1:
The patent creates a local quality difference in axial width between the first and second sliding surfaces. The first sliding surface is made axially wider specifically at the position where heavy loads are applied, while the second sliding surface maintains a narrower width. This localized design allows the first sliding surface to bear heavier loads while the second sliding surface facilitates oil flow into the gap.
Solution Approach 2:
The oil retainer acts as an intermediary element between the first and second sliding surfaces. It protrudes into the gap from the first sliding surface side and serves as a barrier to prevent lubricating oil from flowing out of the gap, while still allowing the oil to be supplied to the first sliding surface. This intermediary structure resolves the conflict between load-bearing capacity and oil retention.
3Reliability
If the oil retainer protrudes towards the first sliding surface, then refrigerant gas is prevented from entering the gap and lubricating oil is kept in the gap, but the device complexity increases
Solution Approach 1:
The oil retainer is merged with the first sliding surface, forming an integrated structure rather than a separate component. The oil retainer is created as a protrusion from the first sliding surface itself, combining the functions of load-bearing surface and oil retention barrier into a single integrated element. This merging reduces device complexity while maintaining the oil retention function.
Solution Approach 2:
The first sliding surface serves multiple functions: it bears heavy loads, provides structural support, and incorporates the oil retainer function through its protrusion into the gap. This multi-functionality reduces the need for separate components, thereby reducing device complexity while achieving reliable oil retention and refrigerant gas prevention.
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 design enhances the reliability of the sliding surfaces by maintaining lubricating oil pressure, reducing refrigerant gas interference, and improving compressor performance by ensuring effective lubrication across the sliding surfaces.
Implementation Method 1
the fitted shaft portion (51) of the drive shaft (35) and the fitted tubular portion (52) sliding on each other with an oil film interposed therebetween
Implementation Method 2
an oil retainer (57) for keeping the lubricating oil in the gap (56) from flowing out toward an end surface of the fitted shaft portion (51)
Implementation Method 3
the groove (55) has a depth that varies in the axial direction
Data Source
Figure 1
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Figure 3
AI summary
A compressor includes a fitted shaft portion (51) and a fitted tubular portion, between which an axially wider first sliding surface (53) and an axially narrower second sliding surface (54) are formed. The fitted shaft portion (51) has a first sliding surface (53) at a portion, in a circumferential direction, of the outer peripheral surface of the fitted shaft portion (51), and a second sliding surface (54), having a smaller axial width than an axial width of the first sliding surface (53), at another portion of the outer peripheral surface in the circumferential direction. A sliding portion between the fitted shaft portion (51) and the fitted tubular portion has a gap (56) which is adjacent to the second sliding surface (54) in the axial direction and into which a lubricating oil flows, and an oil retainer (57) for keeping the lubricating oil in the gap (56) from flowing out of the fitted shaft portion (51).