Oldham Coupling Key Portions for Scroll Compressor Reliability
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Solution Overview
Problem
Existing scroll compressors with Oldham couplings face reliability issues due to insufficient sliding lengths of key portions, leading to increased surface pressure and potential seizure or damage, which affects the compressor's performance.
Innovation Solution
The design includes an Oldham coupling with first key portions that have inwardly positioned surfaces and projections, allowing for longer sliding lengths, and circular arc-shaped inner peripheral edges with different radii, which enables sufficient sliding lengths and reduces weight by adjusting the radial dimension, thereby reducing surface pressure and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sliding lengths of the key portions are increased, then the surface pressure on the sliding surfaces is reduced, but the radial dimension of the annular body portion must be increased
Solution Approach 1:
The patent extends the sliding surfaces of the key portions in the axial direction (perpendicular to the radial direction) by creating inwardly positioned surfaces that project from the horizontal surface toward the center of gravity. This allows the sliding length to be increased without increasing the radial dimension of the annular body portion, effectively moving the solution to another dimension.
Solution Approach 2:
The sliding surface of each key portion is divided into two segments: the conventional sliding surface on the horizontal surface and the additional inwardly positioned sliding surface that projects inward. This segmentation allows the total sliding length to be increased while maintaining the same radial footprint.
2Volume of moving object
If the difference between the outer diameter and inner diameter of the annular body portion is reduced, then the radial dimension is minimized, but the sliding lengths of the key portions become insufficient
Solution Approach 1:
The patent resolves this contradiction by extending the sliding surfaces in the axial direction through inwardly positioned surfaces that project from the horizontal surface. This allows sufficient sliding length to be achieved without increasing the radial dimension or the difference between outer and inner diameters.
Solution Approach 2:
The inwardly positioned surfaces are selectively added only to the key portions where sliding length is needed, rather than uniformly increasing the radial dimension throughout the entire annular body portion. This localized modification achieves the required sliding length while minimizing overall radial dimension.
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 high reliability by minimizing surface pressure on the sliding surfaces of the key portions, preventing issues like seizure and damage, while also reducing the weight of the Oldham coupling by optimizing its radial dimension.
Implementation Method 1
The first key portions have sliding surfaces that slide along the second axis against the movable scroll
Data Source
AI summary
A scroll compressor includes a movable scroll having first key grooves, a stationary member having second key grooves, and an Oldham coupling provided between the movable scroll and stationary member. The Oldham coupling is movable with respect to the stationary member along a first axis, and with respect to the movable scroll along a second axis. The Oldham coupling has an annular body portion, at least two first key portions fitted into the first grooves, and a pair of second key portions fitted into the second grooves. The first horizontal surface has inwardly positioned surfaces positioned more on a center of gravity side of the Oldham coupling than virtual extension lines of first inner peripheral edges that are part of an inner peripheral edge of the annular body portion. The first key portions have inwardly positioned portions that project from the inwardly positioned surfaces.