Key Coupling for Scroll Compressor Reducing Edge Loading
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Solution Overview
Problem
Conventional scroll compressors with Oldham couplings face challenges in preventing relative rotation and efficiently managing angular movement between scroll members, leading to potential unwanted rotation and edge loading issues.
Innovation Solution
The design incorporates a key coupling with six sliding contacts and keys arranged in a non-symmetrical configuration around a ring body, allowing for simultaneous movement along two perpendicular axes while minimizing the diameter and weight of the compressor, thereby reducing unwanted rotation and edge loading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional Oldham coupling with two keys is used to prevent relative rotation between scroll members, then the scroll members are constrained from rotating relative to each other, but the coupling diameter and weight increase, and edge loading issues occur
Solution Approach 1:
The coupling is divided into six separate keys arranged around the ring body, with each key providing a discrete contact point. This segmentation allows the load to be distributed across multiple smaller contact points rather than concentrated on fewer keys, reducing the diameter required and thereby reducing weight while maintaining effective constraint against relative rotation.
Solution Approach 2:
The six keys are positioned in a non-symmetrical configuration around the ring body rather than uniform spacing. This asymmetric arrangement optimizes the geometric relationship between the keys and scroll ribs to minimize the overall coupling diameter while ensuring adequate spacing to prevent edge loading on individual keys during operation.
2Weight of moving object
If the coupling diameter is reduced to minimize weight and housing space, then the compressor diameter and weight decrease, but the spacing between keys is reduced which may cause edge loading
Solution Approach 1:
The non-symmetrical positioning of the six keys around the ring body is designed to optimize spacing between adjacent keys. This asymmetric configuration ensures that even with reduced overall diameter, the keys maintain adequate separation to prevent edge loading while still providing effective rotational constraint.
Solution Approach 2:
The problem of key spacing is solved by distributing six keys around the circumferential dimension of the ring body rather than using fewer keys with larger spacing. This dimensional distribution allows for reduced diameter while maintaining adequate key-to-key spacing through the angular arrangement around the circumference.
3Reliability
If more keys are added to the coupling to distribute loading, then edge loading is reduced and reliability improves, but the device complexity and number of components increase
Solution Approach 1:
The coupling is segmented into six discrete keys that can be independently positioned and engaged with the scroll ribs. This segmentation provides effective load distribution across multiple contact points, improving reliability, while the modular nature of the keys allows for straightforward manufacturing and assembly.
Data Source
AI summary
A scroll compressor includes a fixed scroll compressor body and a moveable scroll compressor body that are arranged for relative orbital movement relative to one another to facilitate compression of refrigerant. The scroll compressor includes a key coupling acting upon the moveable scroll compressor body. The key coupling includes a ring body with a plurality of keys, with key contact surfaces, each of the keys projecting axially from the ring body. The key coupling includes four keys in separate quadrants defined by perpendicular lateral axes. The key coupling guides orbital movement of the moveable scroll compressor body along a linear translational path along a lateral axis.