Scroll Compressor Key Groove Wear Reduction
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Solution Overview
Problem
Scroll compressors experience significant wear at the outer peripheral-side end of the key groove where the Oldham link's key slides, leading to increased friction and reduced reliability, especially during low-speed operation due to inadequate lubrication.
Innovation Solution
The key groove's wall is designed with an offset portion and a surface roughness of 0.2 µm or less, simulating the worn state, and a liner is used to reduce wear by forming a U-shape with a recess and protrusion fitting, ensuring effective lubrication and reduced friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the key groove wall is made highly wear-resistant using hard members or solid lubricant coatings, then wear resistance is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent applies preliminary action by pre-forming an offset portion in the key groove wall before assembly. This offset portion gradually transitions from the reference surface toward the outer peripheral-side end, creating a worn-like profile that reduces key contact stress and prevents initial-stage wear without requiring complex hard coatings or lubricant applications.
Solution Approach 2:
The patent applies local quality by modifying only the specific region of the key groove wall where wear occurs most frequently. The offset portion is localized to extend from the reference surface toward the outer peripheral-side end, concentrating the wear-reduction effect exactly where the key contacts the wall in an inclined state, rather than treating the entire groove uniformly.
2Reliability
If lubricating oil supply is increased, then lubrication effectiveness is improved, but during low-speed operation the oil supply is insufficient leading to increased wear
Solution Approach 1:
The patent applies preliminary action by pre-forming the offset portion in the key groove wall to reduce wear before operation begins. This structural modification ensures that even when lubricating oil supply is insufficient during low-speed operation, the key and key groove wall experience reduced contact stress and wear from the outset, without requiring increased oil flow rates.
3Reliability
If the key groove wall surface is polished to reduce roughness, then initial wear is reduced, but manufacturing time and cost increase
Solution Approach 1:
The patent applies preliminary action by pre-forming the offset portion during the manufacturing process itself, rather than requiring separate polishing operations after assembly. The offset portion is created as part of the key groove formation process, reducing wear before operation begins without adding significant manufacturing steps or time.
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 significantly reduces wear and friction, enhancing the scroll compressor's reliability and operational efficiency by preventing initial-stage wear and maintaining lubricant coatings, even under severe lubricating conditions.
Implementation Method 1
the amount of wear increases gradually, for example, toward the outer peripheral-side end of the key groove, within a range in which the key of the Oldham link shifts relative to the key groove
Implementation Method 2
Once the scroll compressor starts to be used, the surface roughness of the wall of the key groove and the key changes until the sliding surfaces of the key and the wall of the key groove are adapted to each other
Implementation Method 3
Lubricating oil pumped up from an oil storage part inside a housing through an oil supply path inside a rotating shaft is supplied to sliding parts of the scroll compressor, such as the rotating shaft, orbiting scroll, thrust plate, shaft bearing, and Oldham link
Implementation Method 4
the key comes in contact with the wall of the key groove in an inclined state
Data Source
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AI summary
The present invention aims to reduce wear of a key of an Oldham link and a key groove in which the key slides. A scroll compressor (1) includes: a fixed scroll (2), an orbiting scroll (3) revolved relative to the fixed scroll (2); a shaft bearing (6) fixed to a housing (8) and supporting the orbiting scroll (3); and an Oldham link (10) interposed between the orbiting scroll (3) and the shaft bearing (6) and restricting rotation of the orbiting scroll (3). The Oldham link (10) has a first key (11) that slides in a radial direction of a rotating shaft (5) along a wall (21) of a key groove (20) provided in the orbiting scroll (3), and a second key (12) that slides in the radial direction of the rotating shaft (5) along a wall (31) of another key groove (30) provided in the shaft bearing (6). On the assumption of a flat reference surface (210) in the wall (21) of the key groove (20), the wall (21) has an offset portion (21A) that is gradually offset from the reference surface (210) while extending toward at least one of an outer peripheral-side end (20A) and an inner peripheral-side end (20B) of the key groove (20).