Scroll Compressor Wrap With Arcuate And Logarithmic Spiral Sections

Solution Overview

Problem

Conventional scroll compressors have a fixed wrap and orbiting wrap formed in an involute shape, leading to inefficiencies in compression capacity and reliability due to increased size and reduced intensity when attempting to achieve high compression ratios, resulting in a lower compression capacity and reliability issues.

Innovation Solution

The scroll compressor design incorporates a fixed wrap with an arcuate section, a logarithmic spiral section, and a multi-curve section, with the arcuate section extending from the suction end to approximately 180° to 360° and the logarithmic spiral section increasing wrap thickness towards the discharge end, along with a bypass hole to prevent over-compression and enhance compression chamber volume.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If the number of turns of the wrap is increased to obtain a high volume ratio, then the compression ratio is improved, but the compressor size is increased

Engineering Contradiction:

Improvecompression ratioVSAvoidcompressor size

Core Design Contradiction:

Stress or pressureVSVolume of stationary object

Solution Approach 1:

The wrap thickness is made non-uniform, being thinner at the suction end and thicker at the discharge end. This local variation in thickness allows the wrap to maintain sufficient strength at the discharge end where high compression forces occur, while allowing more compression stages (turns) at the suction end where less force is needed, thereby achieving high compression ratio without proportionally increasing overall compressor size

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention changes the parameter of wrap thickness from constant to variable along the wrap length. By making the thickness a varying parameter (increasing from suction end to discharge end), the design optimizes the balance between compression capacity and structural integrity, enabling more turns to be packed into the available space without compromising wrap strength

Inventive Principle:

Principle #35Parameter changes

2Stress or pressure

If the height of the wrap is increased to obtain a high volume ratio, then the compression ratio is improved, but the intensity of the wrap is lowered

Engineering Contradiction:

Improvecompression ratioVSAvoidwrap intensity

Core Design Contradiction:

Stress or pressureVSStrength

Solution Approach 1:

The wrap thickness is made non-uniform, being thinner at the suction end and thicker at the discharge end. This local variation in thickness allows the wrap to maintain sufficient strength at the discharge end where high compression forces occur, while allowing more compression stages (turns) at the suction end where less force is needed, thereby achieving high compression ratio without proportionally increasing overall compressor size

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention changes the parameter of wrap thickness from constant to variable along the wrap length. By making the thickness a varying parameter (increasing from suction end to discharge end), the design optimizes the balance between compression capacity and structural integrity, enabling more turns to be packed into the available space without compromising wrap strength

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If the wrap is formed in an involute shape with uniform thickness, then the manufacturing is simplified, but the compression capacity is reduced due to unused area at outer portion

Engineering Contradiction:

Improvewrap manufacturing simplicityVSAvoidcompression capacity

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The wrap thickness is made non-uniform, being thinner at the suction end and thicker at the discharge end. This local variation in thickness allows the wrap to maintain sufficient strength at the discharge end where high compression forces occur, while allowing more compression stages (turns) at the suction end where less force is needed, thereby achieving high compression ratio without proportionally increasing overall compressor size

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention uses a logarithmic spiral curve instead of a traditional involute curve for the wrap shape. The logarithmic spiral allows the wrap to efficiently utilize the outer portion area of the scroll, creating compression chambers that extend closer to the outer diameter, thereby increasing compression capacity while maintaining manufacturability through a defined mathematical curve

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS9605675B2Scroll compressor with an arcuate and a logarithmic spiral sections

Publication Date: 2017.03.28 LG ELECTRONICS INC

AI summary

A scroll compressor is provided which is configured such that an arcuate section may be formed from a suction end of a wrap to a first point to increase a suction volume, and a logarithmic spiral section in which a wrap thickness increases may be formed from a second point to a discharge end of the wrap. This may increase a volume ratio of the compressor so as to increase a capacity of the compressor and prevent damage to the wrap due to a high compression ratio operation, thereby enhancing reliability of the compressor.