Linear Compressor Asymmetric Gas Inlet Prevents Piston Collision

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Solution Overview

Problem

Existing linear compressors face issues with piston and cylinder collisions due to reduced minimum gaps, leading to instability and potential mechanical failures.

Innovation Solution

The design incorporates a cylinder with a gas inlet and supply ports, featuring first and second gas inlets and supply ports with distinct flow rates and resistances, which increases the minimum gap between the piston and cylinder, preventing collisions and stabilizing the piston's support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single gas inlet and supply port configuration is used, then the structure is simple, but the minimum gap between piston and cylinder decreases leading to collisions

Engineering Contradiction:
Improveprevention of piston-cylinder collisionVSAvoidcylinder structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The single gas inlet and supply port are divided into multiple segments: a first gas inlet with a first supply port, and a second gas inlet with a second supply port. This segmentation allows different gas flows to act on different regions of the piston, creating differential pressure that increases the minimum gap and prevents collisions, while maintaining reasonable structural complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different supply ports are configured with different characteristics (first supply port with larger flow rate, second supply port with smaller flow rate) to create localized pressure differences. This local quality variation enables precise control of the gas bearing pressure distribution, ensuring adequate gap maintenance at critical locations without requiring complete structural redesign

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If gas flow rates through supply ports are equal, then the configuration is symmetric and simple, but the piston support becomes unstable during compression stroke

Engineering Contradiction:
Improvepiston support stabilityVSAvoidgas inlet configuration complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The gas inlet system intentionally uses asymmetric configuration where the first supply port has a larger flow rate than the second supply port. This asymmetry creates differential pressure distribution that provides stable support during the compression stroke, preventing piston-cylinder collision. The asymmetric design is optimized to balance stability improvement against the increased configuration complexity

Inventive Principle:
Principle #4Asymmetry

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 configuration effectively prevents piston and cylinder collisions by increasing the minimum gap, thereby enhancing the reliability and stability of the linear compressor.

Implementation Method 1

the cylinder comprises a gas inlet formed on an outer circumferential surface and a supply port radially passing through the cylinder and communicating with the gas inlet

Methodology Applied
Scientific EffectGas bearing: Air Lubrication

Implementation Method 2

as a difference between pressures of an upper part and a lower part of the piston 150 in a front area of the piston 150 decreased, a levitation force of the piston 150 with respect to a cylinder 140 was weakened

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Data Source

PatentEP3971416B1Linear compressor
Publication Date: 2025.03.05 LG ELECTRONICS INC
  • EP3971416B1 patent drawingFigure 1
  • EP3971416B1 patent drawingFigure 2
  • EP3971416B1 patent drawingFigure 3

AI summary

A linear compressor is disclosed. The linear compressor includes a cylinder that defines a compression space of a refrigerant and has a cylindrical shape, and a piston disposed in the cylinder and reciprocating along an axis of the cylinder. The cylinder includes a gas inlet on an outer circumferential surface and a supply port radially passing through the cylinder and communicating with the gas inlet. The gas inlet includes a first gas inlet and a second gas inlet disposed behind the first gas inlet, and the supply port includes a first supply port communicating with the first gas inlet and a second supply port disposed behind the first supply port and communicating with the second gas inlet. A flow rate passing through the first supply port is different from a flow rate passing through the second supply port.