Spring Cap Resonator in Linear Compressors for Shell Noise Reduction

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Solution Overview

Problem

Existing linear compressors face challenges in effectively canceling noise generated inside the shell, particularly in the 800 Hz band, due to limitations in noise attenuation and increased manufacturing costs and size when separate silencers are installed.

Innovation Solution

The linear compressor incorporates a piston coupled to a linear motor with a compressed coil spring and a spring cap that forms a noise-reducing space, using existing components to create a silencer configuration without additional components, effectively canceling noise by utilizing the spring cap's space and passage portions to resonate and attenuate noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a separate silencer is installed inside the shell to cancel noise, then noise cancellation effectiveness is improved, but manufacturing cost increases due to additional components and assembly steps

Engineering Contradiction:
Improvenoise cancellation effectivenessVSAvoidmanufacturing cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The invention merges the silencer function with the existing spring cap component. The spring cap is modified to include an internal cavity and communication passage, combining the spring support function with noise cancellation function in a single integrated component, thereby eliminating the need for separate silencer components and reducing manufacturing cost

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spring cap is transformed into a multi-functional component that simultaneously serves as a spring support structure and a noise-canceling silencer. By incorporating the cavity and passage into the spring cap, it performs both mechanical support and acoustic attenuation functions

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

2Object-affected harmful factors

If a separate silencer is installed inside the shell to cancel noise, then noise cancellation effectiveness is improved, but the internal volume of the shell must be increased, leading to increased compressor size and weight

Engineering Contradiction:
Improvenoise cancellation effectivenessVSAvoidcompressor size
Core Design Contradiction:
Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The silencer cavity is merged with the existing spring cap volume rather than adding a separate silencer chamber. This integration utilizes the already-present space within the spring cap structure, avoiding additional volume requirements and preventing increase in overall compressor size

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The noise-canceling cavity is nested within the spring cap structure. The passage and cavity are positioned inside the existing component boundaries, effectively hiding the noise cancellation mechanism within the existing structural envelope without expanding the external dimensions

Inventive Principle:
Principle #7Nested doll (Nesting)

3Object-affected harmful factors

If multiple silencers of various standards are installed to offset noise in various frequency bands, then noise cancellation effectiveness across frequency bands is improved, but device complexity increases due to multiple components and assembly steps

Engineering Contradiction:
Improvenoise cancellation effectiveness in various frequency bandsVSAvoidnumber of components
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The spring cap is designed as a universal noise cancellation component that can address multiple frequency bands through its cavity and passage geometry. By optimizing the cavity volume and passage dimensions, a single multi-functional component replaces what would traditionally require multiple frequency-specific silencers

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

Solution Approach 2:

The noise cancellation characteristics are achieved by adjusting geometric parameters of the spring cap (cavity volume, passage cross-section, passage length) rather than by selecting different standardized silencer components. This parametric design allows a single component to effectively address various frequency bands

Inventive Principle:
Principle #35Parameter changes

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 solution allows for effective noise cancellation in various frequency bands without the need for additional silencers, reducing manufacturing costs and maintaining a compact compressor design.

Implementation Method 1

a spring cap onto which an end portion of the spring is supportively inserted. The spring cap includes a space portion having an arbitrary volume and separated from the inner space of the shell, and a passage portion formed through an axial side surface of the space portion to communicate the space portion with the inner space of the shell

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

noise generated inside the shell can be effectively canceled without additionally installing a silencer inside the shell

Methodology Applied
Scientific EffectAcoustic absorption: Acoustic Absorption

Data Source

PatentEP3926169B1Linear compressor
Publication Date: 2022.08.10 LG ELECTRONICS INC
  • EP3926169B1 patent drawingFigure 1
  • EP3926169B1 patent drawingFigure 2
  • EP3926169B1 patent drawingFigure 3

AI summary

The linear compressor according to this embodiment includes a spring supporter configured to reciprocate with being coupled to a piston or a mover of a motor, a resonant spring supported by the spring supporter and supporting the piston, and a spring cap onto which an end portion of the resonant spring is supportively inserted, wherein the spring cap includes a noise reducing space portion having a predetermined volume and separated from an inner space of a shell, and a noise reducing passage portion formed through an axial side surface of the noise reducing space portion to communicate the noise reducing space portion to the inner space of the shell. As a result, noise generated inside the shell can be effectively canceled without additionally installing a separate silencer.