Spiral Plate Spring Structure for Compact Linear Compressors

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Solution Overview

Problem

Conventional linear compressors using coil springs face limitations in miniaturization due to mechanical losses and complexity in arranging multiple springs, while plate springs suffer from reduced rigidity increase with thickness, increased metal loss, and stress concentration issues.

Innovation Solution

A linear compressor design featuring a spiral plate spring with multiple elastic units arranged circumferentially, where each unit has a spirally formed elastic portion, outer, and inner portions, with slits between them, allowing independent movement and reduced stress concentration, enhancing rigidity and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If multiple coil springs are used to reduce eccentricity and tilting, then the stability of the mover is improved, but the device complexity increases and miniaturization is limited

Engineering Contradiction:
Improvestability of moverVSAvoidcomplexity of spring arrangement
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The plate spring is divided into multiple elastic units (first, second, third elastic units) that are circumferentially arranged. Each elastic unit functions as an independent spring element, providing the necessary support and stability while simplifying the overall structure compared to using multiple coil springs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from using coil springs (three-dimensional coiled structure) to a plate spring with elastic units (two-dimensional planar structure). This dimensional change allows the springs to be arranged circumferentially in a plane, reducing the height requirement and simplifying the arrangement while maintaining stability.

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

2Strength

If the thickness of the plate spring is increased to improve rigidity, then the rigidity increases, but the metal loss increases and the punching process becomes more difficult

Engineering Contradiction:
Improverigidity of plate springVSAvoidmetal loss
Core Design Contradiction:
StrengthVSLoss of substance

Solution Approach 1:

The plate spring is segmented into multiple elastic units with slits between them. This segmentation allows the plate spring to achieve the required rigidity through the combined effect of multiple units rather than increasing the thickness of a single solid plate, thereby reducing metal loss.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The elastic units have different local structures - the slits create localized flexible regions while the solid portions maintain strength. This local quality variation allows the plate spring to achieve high rigidity overall while using less material, as the slits reduce metal consumption without significantly compromising structural integrity.

Inventive Principle:
Principle #3Local quality

3Strength

If the width of the slit between elastic units is reduced to improve rigidity, then the rigidity increases, but the stress concentration increases

Engineering Contradiction:
Improverigidity of elastic unitVSAvoidstress concentration
Core Design Contradiction:
StrengthVSStress or pressure

Solution Approach 1:

The invention optimizes the slit width parameter to a specific range (0.5mm to 1.5mm) that balances rigidity and stress concentration. This parameter change allows the elastic units to maintain sufficient rigidity while avoiding excessive stress concentration that would occur with narrower slits.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The slits provide dynamic flexibility to the elastic units, allowing them to deform and absorb stress during operation. This dynamic characteristic reduces stress concentration by enabling the structure to adapt to loading conditions rather than rigidly resisting them.

Inventive Principle:
Principle #15Dynamics

4Strength

If multiple thin plate springs are arranged axially to achieve required rigidity, then the rigidity is improved, but the space efficiency deteriorates

Engineering Contradiction:
Improverigidity of elastic bodyVSAvoidspace efficiency
Core Design Contradiction:
StrengthVSVolume of stationary object

Solution Approach 1:

The invention arranges multiple elastic units circumferentially in a radial pattern rather than stacking them axially. This dimensional rearrangement achieves the required rigidity through radial distribution of elastic units, significantly improving space efficiency by reducing the axial height requirement.

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

Solution Approach 2:

Multiple elastic units are merged into a single integrated plate spring structure with slits between them. This merging allows the elastic units to work together as a unified structure, achieving the required rigidity while occupying less space compared to arranging separate thin plate springs axially.

Inventive Principle:
Principle #5Merging (Combining)

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 design improves rigidity increase with thickness, reduces metal loss, simplifies manufacturing, and enhances durability and reliability by minimizing stress concentration and interference, leading to improved space efficiency and reduced noise and abrasion.

Implementation Method 1

an elastic body for a linear compressor configured to compress a refrigerant by the linear reciprocating motion of a piston

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4015820B1Elastic body and linear compressor including the same
Publication Date: 2024.01.10 LG ELECTRONICS INC
  • EP4015820B1 patent drawingFigure 1
  • EP4015820B1 patent drawingFigure 2
  • EP4015820B1 patent drawingFigure 3

AI summary

An elastic body (191) and a linear compressor (100) including the elastic body (191) are provided. The elastic body according to an aspect of the present disclosure includes a plurality of elastic units (1911) disposed circumferentially around an axis, each of the plurality of elastic units has a corresponding shape, each of the plurality of elastic units includes an elastic portion (1911a) that is spirally formed while moving away from the axis, an outer portion (1911c) disposed on an outside of the elastic portion in a radial direction thereof, and an inner portion (1911b) disposed on an inside of the elastic portion in the radial direction thereof, the outer portion is adjacent to the outer portion of an adjacent elastic unit, the inner portion is adjacent to the inner portion of the adjacent elastic unit, and a slit (1912-1914) is formed between the plurality of elastic portions.