Scroll Compressor Suction Pipe Oil Distribution

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Solution Overview

Problem

Existing scroll compressors have difficulty supplying oil to spaces radially inward and outward of the movable scroll, leading to inefficient oil distribution and sealing performance in the compression chamber.

Innovation Solution

The suction pipe design includes a larger-diameter portion, a smaller-diameter portion, and a diameter-reducing portion, with the smaller-diameter portion having an outer diameter smaller than the suction port, allowing oil to flow into the suction port and be distributed efficiently to both inward and outward spaces of the compression chamber. Additionally, configurations such as a tapered suction port and precise positioning of the suction pipe's downstream end enhance oil flow and distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the suction pipe has a larger-diameter portion with outer diameter larger than the suction port opening, then oil can adhere to the outer circumferential surface and fall down naturally to reduce oil entry into the suction port, but oil cannot be supplied effectively to spaces radially inward and outward of the movable scroll

Engineering Contradiction:
Improveoil entry into suction portVSAvoidoil supply to compression chamber spaces
Core Design Contradiction:
Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The suction pipe is divided into three distinct portions: a larger-diameter portion for oil adhesion and separation, a smaller-diameter portion for creating the gap flow path, and a diameter-reducing portion for smooth transition. This segmentation allows the pipe to simultaneously prevent oil entry while supplying oil to compression chamber spaces through the gap between the smaller-diameter portion and suction port

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the suction pipe are designed with different diameters to perform different functions. The larger-diameter portion handles oil separation, while the smaller-diameter portion enables gap flow for oil supply to compression spaces. This local quality differentiation resolves the contradiction between oil prevention and oil supply

Inventive Principle:
Principle #3Local quality

2Loss of substance

If the movable-side oil groove communicates only with the fixed-side oil groove and not with compression chamber spaces, then oil loss is reduced, but oil sealing performance in compression chamber spaces deteriorates

Engineering Contradiction:
Improveoil lossVSAvoidoil sealing performance
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The suction port acts as an intermediary mechanism that enables oil supply to compression chamber spaces without direct communication between the movable-side oil groove and the spaces. Oil flows through the suction port via the gap between the smaller-diameter portion and suction port, providing lubrication and sealing while minimizing direct oil loss

Inventive Principle:
Principle #24Intermediary (Mediator)

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 ensures effective oil supply to both radially inward and outward spaces of the movable scroll, improving oil sealing performance and compressor efficiency by ensuring oil flows smoothly into the suction port and is distributed effectively within the compression chamber.

Implementation Method 1

The oil contained in the refrigerant flowing through the internal space of the dome adheres to the outer circumferential surface of the joint pipe

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

The outer diameter of the joint pipe is larger than the opening of the suction port. Therefore the oil that has adhered to the outer circumferential surface of the joint pipe falls down naturally

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 3

The outer diameter of the smaller-diameter portion (12b) is smaller than the inner diameter of the upstream end of the suction port (64). The oil flowing through the internal space (23) flows into the suction port (64) through the gap between the smaller-diameter portion (12b) of the suction pipe (12) and the suction port (64)

Methodology Applied
Scientific EffectFluid flow through gap:

Data Source

PatentEP3992461B1Scroll compressor
Publication Date: 2023.10.11 DAIKIN INDUSTRIES LTD
  • EP3992461B1 patent drawingFigure 1
  • EP3992461B1 patent drawingFigure 2
  • EP3992461B1 patent drawingFigure 3

AI summary

A downstream end of a suction pipe (12) overlaps with an upstream end of a suction port (64) as viewed in the axial direction. A casing (20) has therein an internal space (23) through which a refrigerant containing oil flows. A fixed scroll (60) has a suction port (64) communicating with the internal space (23) and a compression chamber (S). The refrigerant flowing through the internal space (23) and containing oil droplets (25) passes through a gap between the downstream end of the suction pipe (12) and an open surface (60a) of the suction port (64) and flows into the suction port (64).