Compressor Pump Assembly for Low Pressure Ratio Oil Supply

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Solution Overview

Problem

Compressors face challenges in maintaining effective and active oil supply in low pressure ratio driving areas, where pressure differences are minimal, limiting the compressor's operational range from low to high speeds.

Innovation Solution

A compressor design that incorporates a pump assembly for oil supply, which is precisely matched to the center and stably fixed, allowing for oil pumping by the rotary shaft, supplemented by oil supply based on pressure differences, ensuring continuous and effective lubrication even in areas with low pressure ratios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If oil supply is based on pressure difference between high pressure space and low pressure space, then oil can be supplied in high pressure ratio driving areas, but effective and active oil supply cannot be maintained in low pressure ratio driving areas

Engineering Contradiction:
Improveoil supply reliabilityVSAvoiddriving area range
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The oil supply system is segmented into two independent pathways: a pressure difference-based oil supply path for high pressure ratio conditions, and a pump assembly-based oil supply path for low pressure ratio conditions. This segmentation allows each pathway to be optimized for its specific operating condition, resolving the contradiction between reliability in high pressure areas and adaptability across all driving areas.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between two oil supply mechanisms based on operating conditions. The pump assembly is selectively activated in low pressure ratio driving areas while the pressure difference mechanism operates in high pressure ratio areas. This dynamic adaptation enables the system to maintain reliable oil supply across the entire driving area range from low to high speeds.

Inventive Principle:
Principle #15Dynamics

2Reliability

If a pump assembly is added for oil supply, then effective oil supply can be achieved in low pressure ratio areas, but device complexity increases

Engineering Contradiction:
Improveoil supply effectivenessVSAvoidoil supply system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pump assembly is merged with the existing rotary shaft, allowing the rotary shaft to serve dual functions: compression drive and oil pumping. This integration eliminates the need for a completely separate pump mechanism, thereby adding oil supply effectiveness in low pressure areas while minimizing the increase in device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rotary shaft is designed with multi-functionality, serving both as the drive shaft for compression and as the driving element for the pump assembly. This universal design allows a single component to perform multiple functions, reducing overall system complexity while achieving reliable oil supply across all operating conditions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of manufacture

If the pump assembly is not precisely matched and fixed to the center, then manufacturing is easier, but oil supply stability and lubrication effectiveness decrease

Engineering Contradiction:
Improvepump assembly installationVSAvoidoil supply stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The pump assembly is designed with a structure that naturally aligns with the rotational center, creating a self-centering effect. The symmetric design and uniform distribution of pumping elements around the rotary shaft ensure that the pump assembly remains centered during operation without requiring complex external alignment mechanisms, thus maintaining both ease of manufacture and oil supply stability.

Inventive Principle:
Principle #12Equipotentiality

Solution Approach 2:

The pump assembly incorporates self-aligning features that automatically center it relative to the rotary shaft during assembly or operation. This self-service capability eliminates the need for precise manual alignment or complex external positioning mechanisms, achieving both ease of manufacture and reliable oil supply stability.

Inventive Principle:
Principle #25Self-service

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 enhances the compressor's operational range by providing reliable oil supply and maintaining efficient lubrication, thereby extending the driving area and preventing wear on components.

Implementation Method 1

A pressure difference between a lower low oil space which is a high pressure space in a case and a low pressure space of a compression chamber where a refrigerant is compressed is used. That is, an oil path is formed between the lower low oil space and the low pressure space of the compression chamber, whereby oil is supplied due to the pressure difference.

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Implementation Method 2

a centrifugation space defined inside the case by a downstream side of the driving motor and the case, enabling centrifugation of a compressed refrigerant and a lubricant oil

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3819462B1compressor
Publication Date: 2025.03.26 LG ELECTRONICS INC
  • EP3819462B1 patent drawingFigure 1
  • EP3819462B1 patent drawingFigure 2~3
  • EP3819462B1 patent drawingFigure 4~5

AI summary

A compressor is disclosed, which enables effective and active oil supply required for lubrication of a compression portion for compressing a refrigerant. The compressor comprises a case; a driving motor including a stator provided at an inner side of the case and a rotor rotatably provided at an inner side in a radius direction of the stator; a centrifugation space defined inside the case by a downstream side of the driving motor and the case, enabling centrifugation of a compressed refrigerant and a lubricant oil; a discharge pipe provided in the case, discharging the refrigerant inside the centrifugation space to the outside of the case; a rotary shaft rotated by being coupled to the rotor and provided with an oil supply path; a compression portion provided at an upstream side of the driving motor, compressing the refrigerant through rotation of the rotary shaft; a pump assembly provided below the rotary shaft, pumping oil by being rotated in a single body with the rotary shaft; and an oil pickup forming an oil supply path between the pump assembly and a low oil space formed inside the case.