Linear compressor

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Solution Overview

Problem

Existing linear compressors face challenges in reducing noise in the low and mid-frequency bands, maintaining space efficiency, and preventing interference between muffler units and spring supporters, while also addressing issues of oil lubrication and reliability.

Innovation Solution

The linear compressor incorporates a second muffler unit with a muffler body and cover, featuring a resonator space and specific flange configurations to reduce noise and improve space efficiency, and prevents interference with a spring supporter by using a press-fitted design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a muffler unit is coupled to the piston for noise reduction, then noise is reduced, but the noise reduction effect is lowered due to limited space

Engineering Contradiction:
ImprovenoiseVSAvoidspace
Core Design Contradiction:
Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The first muffler unit is nested within the second muffler unit, with the first intake muffler positioned inside the second intake muffler. This nested configuration allows both muffler units to occupy the same spatial envelope, maximizing noise reduction effectiveness while minimizing the overall space required in the limited compressor environment.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent utilizes the axial dimension by positioning the first muffler unit closer to the piston and the second muffler unit further away, creating a multi-layered noise reduction system along the axial direction. This dimensional arrangement allows effective noise reduction without requiring excessive radial or lateral space.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If a second muffler unit is added to improve noise reduction, then noise reduction effect is enhanced, but device complexity increases

Engineering Contradiction:
ImprovenoiseVSAvoidstructure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The first and second muffler units are merged into a single integrated assembly that is coupled to the piston as one unit. The intake guides and muffler sections are combined in a way that creates a unified noise reduction system, reducing the number of separate components and simplifying installation while maintaining enhanced noise reduction capabilities.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The second muffler unit is designed to serve multiple functions: it provides additional noise reduction for frequencies that the first muffler unit cannot effectively attenuate, while also serving as a structural housing that contains the first muffler unit and provides mounting interfaces to the piston. This multi-functionality reduces overall system complexity.

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

3Volume of moving object

If muffler units are positioned close to each other to save space, then space efficiency is improved, but interference between muffler units and spring supporter occurs

Engineering Contradiction:
ImprovespaceVSAvoidinterference prevention
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent creates distinct local zones around the muffler units and spring supporter, ensuring that each component has its own designated space. The first and second muffler units are positioned in regions that do not overlap with the spring supporter's operational path, while still maintaining compact overall dimensions. This local spatial differentiation prevents interference while preserving space efficiency.

Inventive Principle:
Principle #3Local quality

4Temperature

If oil lubrication is used to suppress overheating, then thermal management is improved, but oil shortage reduces reliability

Engineering Contradiction:
Improveoverheating suppressionVSAvoidoil shortage
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent introduces refrigerant as an intermediary substance that supplements the oil lubrication system. The refrigerant serves as a secondary lubricant and cooling medium that can be supplied to the compression chamber when oil is insufficient, thereby maintaining reliable operation and preventing both overheating and oil-shortage failures through this intermediary resource.

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

The solution effectively reduces noise in the low and mid-frequency bands, enhances space efficiency, and prevents interference between muffler units and spring supporters, thereby improving the reliability and performance of the compressor.

Implementation Method 1

a resonator space defined between the muffler body and the muffler cover

Methodology Applied
Scientific EffectAcoustic resonance: Resonance

Implementation Method 2

the muffler body is press-fitted to the back cover

Methodology Applied
Scientific EffectMechanical interference fit: Mechanical Fastener

Data Source

PatentEP4345311B1Linear compressor
Publication Date: 2025.08.06 LG ELECTRONICS INC
  • EP4345311B1 patent drawingFigure 1
  • EP4345311B1 patent drawingFigure 2
  • EP4345311B1 patent drawingFigure 3~4

AI summary

A linear compressor includes a cylinder, a piston axially reciprocating in the cylinder, a first muffler unit coupled to the piston, a back cover that is disposed at a rear of the piston and defines an opening at a radially central area, and a second muffler unit coupled to the opening. The first muffler unit includes an inner guide disposed in the piston and a first intake muffler disposed at a rear of the inner guide. The second muffler unit includes a second intake muffler that communicates with the first intake muffler and is coupled to the opening, a muffler body surrounding the second intake muffler, and a muffler cover disposed between the muffler body and the back cover.