Scroll Compressor Motor Layout to Reduce Refrigerant Oil Outflow

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Solution Overview

Problem

In scroll compressors, there is a risk of oil flowing out along with refrigerant through the discharge pipe, leading to inefficiencies and potential damage.

Innovation Solution

The scroll compressor design includes an outgoing line and film wound around it, positioned to satisfy specific radius ratios and coverage areas, which inhibits oil from moving with refrigerant and reduces outflow by guiding refrigerant through controlled gaps and collisions with the casing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If refrigerant is discharged from the compression mechanism through space above the motor to cool the motor, then motor cooling is improved, but oil flows out together with the refrigerant through the discharge pipe

Engineering Contradiction:
Improvemotor temperatureVSAvoidoil outflow
Core Design Contradiction:
TemperatureVSLoss of substance

Solution Approach 1:

The outgoing line acts as an intermediary structure that the refrigerant must pass through on its way from the compression mechanism to the discharge pipe. By positioning this line with specific radial distance from the rotor axis, it serves as a barrier that intercepts oil particles carried by the refrigerant flow, preventing them from reaching the discharge pipe while allowing the refrigerant to continue its cooling function.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention extracts the oil separation function from the main refrigerant flow path by introducing a dedicated structural element (the outgoing line) that specifically targets and removes oil particles from the mixture. This separates the oil removal function from the refrigerant cooling function, allowing both to occur simultaneously but independently.

Inventive Principle:
Principle #2Taking out (Extraction)

2Loss of substance

If the outgoing line is positioned closer to the rotor axis, then oil inhibition is improved, but refrigerant flow guidance is reduced

Engineering Contradiction:
Improveoil outflowVSAvoidrefrigerant flow
Core Design Contradiction:
Loss of substanceVSProductivity

Solution Approach 1:

The invention optimizes the radial distance parameter of the outgoing line from the rotor axis to a specific range (0.3 to 0.7 times the stator outer radius). This parameter optimization balances two competing requirements: being close enough to the center to effectively intercept oil particles, yet far enough to maintain adequate refrigerant flow guidance and avoid excessive flow resistance.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the outgoing line is positioned farther from the rotor axis, then refrigerant flow guidance is improved, but oil inhibition is reduced

Engineering Contradiction:
Improverefrigerant flowVSAvoidoil outflow
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The invention establishes an optimal parameter range for the radial distance of the outgoing line (0.3 to 0.7 times the stator outer radius) that simultaneously satisfies both refrigerant flow requirements and oil inhibition requirements. This parameter optimization ensures the outgoing line is positioned far enough to guide refrigerant flow effectively while remaining close enough to intercept oil particles before they reach the discharge pipe.

Inventive Principle:
Principle #35Parameter changes

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 effectively reduces the amount of oil flowing out with the refrigerant, enhancing the compressor's reliability and efficiency while maintaining structural integrity.

Implementation Method 1

refrigerant passing through a gap between the coils

Methodology Applied
Scientific EffectFluid flow through gap:

Implementation Method 2

the end face of the stator is covered to some extent. As a result, it is possible to inhibit oil from moving together with the refrigerant

Methodology Applied
Scientific EffectPhysical barrier coverage:

Implementation Method 3

heads for the inner peripheral surface of the casing, colliding with the inner peripheral surface of the casing

Methodology Applied
Scientific EffectFluid collision with surface: Impact Force

Data Source

PatentEP4067660B1Scroll compressor
Publication Date: 2024.01.17 DAIKIN INDUSTRIES LTD
  • EP4067660B1 patent drawingFigure 1
  • EP4067660B1 patent drawingFigure 2~3
  • EP4067660B1 patent drawingFigure 4~5

AI summary

A reliable scroll compressor that can reduce outflow of oil is provided. The scroll compressor (10) includes a compression mechanism (30) that compresses a refrigerant, a motor (40) that drives the compression mechanism, and a casing (20) housing the compression mechanism and the motor. The motor includes a stator (50) including a stator core (52) and an insulator (54), a rotor (60) disposed inside the stator, a coil (42), and an outgoing line (70) provided at an end of the coil. The coil is wound around a plurality of teeth of the stator core via the insulator. When the motor is viewed along a rotation axis (O) of the rotor, it is assumed that an outer radius of the teeth centered on a position of the rotation axis (O) is D1 and an inner radius of the teeth is D2, and that an average distance from the position of the rotation axis (O) to the outgoing line and/or a film wound around the outgoing line is da. The outgoing line and/or the film wound around the outgoing line is disposed to satisfy the relationship of 0.65 < (D1 - da)/(D1 - D2) < 0.95.