Rotary Compressor Roller Key Assembly for Bearing Wear Control

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Solution Overview

Problem

Existing rotary compressors face issues such as friction loss and abrasion between the roller and bearings, leakage between compression chambers, increased manufacturing costs due to complex assembly processes, and limitations in material selection for the roller and rotating shaft, which affect efficiency and reliability.

Innovation Solution

A rotary compressor design that includes a rotation preventing unit with a rotation preventing groove in the roller and a rotation preventing key on the rotating shaft, allowing for relative motion while constraining axial movement, enabling separate manufacturing and assembly of the roller and shaft, and allowing for different material selection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the roller and rotating shaft are manufactured as a single body, then coupling reliability is improved, but friction loss and abrasion occur between the roller and bearing, and leakage between compression chambers increases

Engineering Contradiction:
Improvecoupling reliabilityVSAvoidfriction loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The roller and rotating shaft are divided into separate components that can be assembled together. The roller is inserted into the rotating shaft through a shaft hole, allowing independent manufacturing and assembly while maintaining coupling reliability. This segmentation enables the roller to move axially relative to the shaft, preventing friction loss and abrasion between the roller and bearing.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If the roller and rotating shaft are manufactured as a single body, then assembly process is simplified, but material selection is limited and weight reduction is constrained

Engineering Contradiction:
Improveassembly processVSAvoidroller weight
Core Design Contradiction:
Ease of manufactureVSWeight of moving object

Solution Approach 1:

The roller and rotating shaft are manufactured separately and then assembled. This allows different materials to be selected for each component based on their specific functional requirements. The roller can be made from lighter materials optimized for its specific function, while the shaft can use materials optimized for structural requirements, enabling overall weight reduction while maintaining assembly simplicity.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If the roller and rotating shaft are post-assembled, then material selection flexibility is improved, but manufacturing time and cost increase due to additional assembly and post-machining processes

Engineering Contradiction:
Improvematerial selection flexibilityVSAvoidmanufacturing time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The shaft hole is formed in advance during the roller manufacturing process, before assembly with the rotating shaft. This preliminary action eliminates the need for complex post-assembly machining operations, reducing manufacturing time and cost while maintaining the flexibility of separate component manufacturing and material selection.

Inventive Principle:
Principle #10Preliminary action

4Manufacturing precision

If the roller is allowed to move axially with the rotating shaft during magnetic centering, then rotor-stator alignment is achieved, but friction loss and abrasion occur between the roller and main bearing

Engineering Contradiction:
Improverotor-stator alignmentVSAvoidfriction loss
Core Design Contradiction:
Manufacturing precisionVSLoss of energy

Solution Approach 1:

The roller is designed to move axially relative to the rotating shaft during the magnetic centering process to achieve proper rotor-stator alignment. After alignment is achieved, the roller's axial movement is constrained by the shaft hole, preventing further friction loss and abrasion between the roller and main bearing while maintaining the achieved alignment precision.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4212727B1Rotary compressor
Publication Date: 2025.07.09 LG ELECTRONICS INC
  • EP4212727B1 patent drawingFigure 1
  • EP4212727B1 patent drawingFigure 2
  • EP4212727B1 patent drawingFigure 3

AI summary

Provided is a rotary compressor. The rotary compressor includes a rotation preventing key between a roller and a rotating shaft: The roller is a separable-type roller assembled into the rotating shaft. The rotation preventing unit may constrain rotation of the roller and allow axial movement of the roller with respect to the rotating shaft. Thus, axial movement of the roller along the rotating shaft may be suppressed, and thus, friction loss and abrasion between the roller and a main bearing or between the roller or a sub bearing may be suppressed.