Compressor Roller Curvature Matching Cylinder Surface

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Solution Overview

Problem

Conventional rotary compressors with oval-shaped rollers experience increased frictional loss due to point-contact with the cylinder, which hinders the formation of a smooth oil film and results in compression losses.

Innovation Solution

The design incorporates a roller with a lubrication surface that matches the curvature of the cylinder, ensuring a wider surface contact and forming an oil film, with specific angles and oil passage configurations to minimize friction and compression losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If an oval-shaped roller is used in a conventional rotary compressor, then the structure is simple and manufacturing is easy, but point-contact between the roller and cylinder increases frictional loss and prevents smooth oil film formation

Engineering Contradiction:
Improveroller manufacturing simplicityVSAvoidfrictional loss
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The roller is designed with a curved surface that matches the curvature of the cylinder inner circumferential surface. This curvature modification transforms the contact geometry from point-contact to surface-contact, enabling smooth oil film formation and reducing frictional loss while maintaining manufacturing feasibility.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

An oil film is introduced as an intermediary layer between the roller and cylinder surfaces. The curved roller surface facilitates the formation and distribution of this oil film, which acts as a mediator to reduce direct metal-to-metal contact and minimize frictional energy loss.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the roller contacts the cylinder at multiple points, then oil film formation is improved, but compression space volume may be reduced

Engineering Contradiction:
Improveoil film formation qualityVSAvoidcompression space volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The roller surface is designed with different local qualities: a curved lubrication surface for oil film formation and a compression surface for maintaining compression space volume. This local differentiation allows the roller to simultaneously achieve reliable lubrication and preserve compression efficiency.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention addresses the two-dimensional conflict between contact area and compression volume by introducing a dimensional solution through precise surface curvature design. The curved lubrication surface extends the contact area in the radial dimension while the overall roller geometry maintains the necessary compression space volume.

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

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 reduces frictional losses and enhances compression efficiency by forming a wide-area oil film between the roller and cylinder, while maintaining or increasing compression space volume.

Implementation Method 1

an oil film is formed between the roller and the cylinder with a wide area, thereby a frictional loss may be reduced

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3194785B1compressor
Publication Date: 2023.07.19 LG ELECTRONICS INC
  • EP3194785B1 patent drawingFigure 1
  • EP3194785B1 patent drawingFigure 2
  • EP3194785B1 patent drawingFigure 3

AI summary

Disclosed is a compressor. A lubrication surface, which has the same curvature as an inner circumferential surface curvature of a cylinder and which has a predetermined circumference length, is formed on an outer circumferential surface of a roller contacting an inner circumferential surface of the cylinder. With such a configuration, since the outer circumferential surface of the roller contacting the inner circumferential surface of the cylinder come in surface-contact with each other, an oil film is formed between the roller and the cylinder with a wide area. This can reduce a frictional loss.