Linear Compressor Muffler Coupling Without Welding Gaps

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Solution Overview

Problem

Linear compressors face challenges in coupling muffler units securely without welding, leading to potential gaps and reduced noise reduction effectiveness, especially in gas lubricated compressors where oil lubrication is not used, and there is a risk of oil shortage affecting reliability.

Innovation Solution

A linear compressor design that couples a back cover of metal material with a second muffler unit of non-metal material using a coupling portion that passes through an opening and is rotatable, allowing press-fitting without welding, and includes an elastic member to guide position and enhance stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a muffler unit is coupled to the back cover without welding, then ease of manufacture is improved, but coupling stability deteriorates due to potential gaps

Engineering Contradiction:
Improveease of manufactureVSAvoidcoupling stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

A coupling portion with a coupling hole is introduced as an intermediary element between the muffler unit and back cover. This coupling portion includes a coupling protrusion that fits into the coupling hole, creating a mechanical interlocking structure that provides stable coupling without requiring welding processes.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The coupling system is divided into separate components: the coupling portion with coupling hole in the back cover, and the coupling protrusion on the muffler unit. This segmentation allows for separate manufacturing of each component followed by precise assembly, improving ease of manufacture while maintaining coupling stability through the interlocking design.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If a coupling portion is used to connect back cover and muffler unit, then coupling stability is improved, but device complexity increases

Engineering Contradiction:
Improvecoupling stabilityVSAvoiddevice complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The coupling hole is integrated directly into the back cover structure, and the coupling protrusion is formed as part of the muffler unit assembly. By merging these coupling features with the existing structural components rather than adding separate fastening mechanisms, the design achieves stable coupling while minimizing increases in device complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If oil lubrication is used, then reliability is improved through better lubrication, but risk of oil shortage increases

Engineering Contradiction:
ImprovereliabilityVSAvoidoil shortage
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The gas lubricated linear compressor uses the refrigerant gas itself to provide lubrication between moving parts through gas film formation. This self-service lubrication system eliminates the need for separate oil supply and circulation systems, preventing oil shortage issues while maintaining reliable operation through the gas-based lubrication mechanism.

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 achieves stable coupling between the back cover and muffler unit, eliminating gaps and improving noise reduction while maintaining reliability by preventing oil shortage and reducing mechanical losses.

Implementation Method 1

an elastic member to guide position of the second muffler unit and enhance stability

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a coupling portion of a second intake muffler coupled to an opening of a back cover without a separate process such as welding

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4345307B1Linear compressor
Publication Date: 2026.02.18 LG ELECTRONICS INC
  • EP4345307B1 patent drawingFigure 1
  • EP4345307B1 patent drawingFigure 2
  • EP4345307B1 patent drawingFigure 3~4

AI summary

A linear compressor (100) includes a cylinder (140), a piston (150) axially reciprocating in the cylinder, a first muffler unit (160) coupled to the piston, a back cover (123) that is disposed at a rear of the piston and defines an opening (1230) at a radially central area, and a second muffler unit (200) coupled to the opening. The first muffler unit includes an inner guide (162) disposed in the piston and a first intake muffler (161) disposed at a rear of the inner guide. The second muffler unit includes a second intake muffler (210) that is in fluid communication with the first intake muffler and is coupled to the opening, and a muffler body (220) surrounding the second intake muffler. The second intake muffler includes a coupling portion (218) that is disposed at a rear of the second intake muffler and has a shape corresponding to the opening.