Linear Compressor Gas Bearing Friction Reduction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The existing linear compressor has a large volume, which is not suitable for refrigerators aiming to increase inner storage space, and reducing its size compromises performance, leading to deteriorated efficiency due to increased friction from oil circulation at higher drive frequencies.

Innovation Solution

The design incorporates a gas bearing system using refrigerant as a lubricant, with filters to remove foreign substances and oil, and a sealing mechanism that allows the refrigerant to flow between the cylinder and frame, reducing friction and enabling higher drive frequencies without performance deterioration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the size of the linear compressor is reduced to increase refrigerator storage space, then the volume of the compressor is decreased, but the performance deteriorates due to increased friction from oil circulation at higher drive frequencies

Engineering Contradiction:
Improvecompressor volumeVSAvoidcompressor performance
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent extracts and removes the oil circulation system from the compressor. By eliminating the oil supply assembly and oil circulation mechanism, the invention eliminates the source of friction that would otherwise deteriorate performance at higher drive frequencies. The compressor operates without oil lubrication, using alternative sealing and bearing mechanisms that do not require oil circulation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical oil lubrication system with a different operational mechanism. Instead of using oil to reduce friction between moving parts, the invention employs a design where the piston and cylinder operate without oil circulation, utilizing alternative methods for reducing friction and wear that are compatible with high-frequency operation and compact dimensions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If the drive frequency is increased to compensate for deteriorated performance in a smaller compressor, then the compression efficiency is improved, but the friction force increases due to oil circulation

Engineering Contradiction:
Improvecompression efficiencyVSAvoidfriction force
Core Design Contradiction:
ProductivityVSForce

Solution Approach 1:

The patent removes the oil circulation system entirely, eliminating the mechanism that generates friction force. By taking out the oil supply assembly and oil circulation path, the invention prevents friction force from increasing at higher drive frequencies, allowing the compressor to operate efficiently at high frequencies without the penalty of oil-related friction.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The compressor is designed to operate without external oil lubrication. The system is self-sufficient, using its own operational parameters and alternative sealing mechanisms to maintain low friction conditions. The piston and cylinder are designed to work together without requiring oil circulation, making the system self-service in terms of lubrication.

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 approach reduces the compressor's size, increases storage space, and minimizes friction-related performance losses by using refrigerant as a bearing, enhancing operational reliability and efficiency.

Implementation Method 1

at least a portion of the refrigerant discharged through the discharge valve may flow toward an outer circumferential surface of the cylinder to allow the refrigerant to serve as a bearing

Methodology Applied
Scientific EffectGas bearing: Air Lubrication

Data Source

PatentEP2960505B1Linear compressor
Publication Date: 2018.06.13 LG ELECTRONICS INC
  • EP2960505B1 patent drawingFigure 1~2
  • EP2960505B1 patent drawingFigure 3
  • EP2960505B1 patent drawingFigure 4~5

AI summary

A linear compressor is provided. The linear compressor may include a shell including a suction inlet, a cylinder provided in the shell to define a compression space for a refrigerant, a piston reciprocated in an axial direction within the cylinder, a discharge valve provided on or at one side of the cylinder to selectively discharge the refrigerant compressed in the compression space, at least one nozzle disposed in the cylinder to introduce at least a portion of the refrigerant discharged through the discharge valve into the cylinder, and a passage to guide the refrigerant discharged from the discharge valve to the at least one nozzle.