Non-symmetrical Key Coupling Contact Scroll Compressor Backlash

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Solution Overview

Problem

Existing scroll compressors face challenges in preventing relative angular movement between scroll members during orbital motion, leading to rotational backlash and inefficiencies in refrigerant compression.

Innovation Solution

A nonsymmetrical cooperating sliding contact arrangement between the key coupler and scroll compressor bodies, with uneven running clearance distribution along mutually perpendicular lateral axes, is implemented to guide movement and prevent rotational backlash.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a symmetrical Oldham coupling is used to guide movement between scroll bodies, then the structure is simple and easy to manufacture, but rotational backlash occurs and alignment precision deteriorates

Engineering Contradiction:
Improvealignment precisionVSAvoidcoupling structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by providing uneven running clearance between the key coupler and sliding contacts. Specifically, the running clearance is smaller on one side and larger on the other side, creating an asymmetrical configuration that prevents rotational backlash while maintaining ease of manufacture. This asymmetrical clearance distribution allows the coupling to self-correct alignment errors during operation.

Inventive Principle:
Principle #4Asymmetry

2Ease of operation

If running clearance is provided between key coupler and scroll bodies, then ease of operation and assembly is improved, but rotational backlash increases

Engineering Contradiction:
Improveease of assemblyVSAvoidprevention of rotational backlash
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies local quality by distributing running clearance non-uniformly across different locations of the key coupler. Instead of providing equal clearance everywhere, the design specifies smaller clearance in certain regions and larger clearance in other regions. This localized variation in clearance allows the system to maintain ease of assembly while preventing rotational backlash through the strategic placement of tighter clearance zones.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2245271B1Non symmetrical key coupling contact and scroll compressor having same
Publication Date: 2016.11.30 BITZER KUEHLMASCHINENBAU GMBH
  • EP2245271B1 patent drawingFigure 1
  • EP2245271B1 patent drawingFigure 2
  • EP2245271B1 patent drawingFigure 3

AI summary

A scroll compressor includes a movable scroll compressor body and a fixed scroll compressor body that are arranged for relative orbital movement relative to one another to facilitate compression of refrigerant. To guide the orbital movement, a Oldham key coupling is provided that may include four keys spaced in separate quadrants for guiding movement of the scroll compressor body along a linear translational path along a lateral axis. Additionally, running clearances may be unequally and non-symmetrically arranged so as to prevent unwanted rotation of one of the scroll compressor bodies and thereby prevent unwanted edge loading.