Crank Shaft Partition Structure for High-Eccentricity Compressor Sealing

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Solution Overview

Problem

Existing double-rotor compressors face challenges in miniaturization and cost reduction due to increased size and eccentricity, leading to refrigerant leakage and sealing issues between the partition plate and roller.

Innovation Solution

A pump body assembly with a crank shaft featuring a central rotating shaft, first and second eccentric components, a disc partition plate integrally formed with the central rotating shaft, and an annular partition plate, which avoids the need for mounting holes and simplifies the partition plate structure, allowing for increased eccentricity without leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the eccentricity of the crank shaft is increased to achieve greater displacement, then the compressor displacement is improved, but the gap between the roller and partition plate increases causing refrigerant leakage

Engineering Contradiction:
Improvecompressor displacementVSAvoidsealing performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent transitions from a single flat partition plate to a three-dimensional annular partition plate with stepped structure. This dimensional change allows the partition plate to wrap around the eccentric component, creating sealing surfaces in multiple radial positions rather than a single plane, thereby maintaining sealing effectiveness with increased eccentricity.

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

Solution Approach 2:

The annular partition plate is divided into multiple stepped levels with different radial positions. Each step creates a separate sealing zone, allowing the refrigerant to be contained at multiple radial distances from the center. This segmentation enables the partition plate to maintain effective sealing contact despite the increased gap at any single location.

Inventive Principle:
Principle #1Segmentation

2Productivity

If the height and diameter of the cylinder are increased to achieve greater displacement, then the compressor displacement is improved, but the overall size of the structure increases

Engineering Contradiction:
Improvecompressor displacementVSAvoidcompressor size
Core Design Contradiction:
ProductivityVSVolume of moving object

Solution Approach 1:

The patent changes the geometric parameters of the crank shaft system by increasing the eccentricity distance between the rotation center and the roller center. This parameter change allows the compressor to achieve greater displacement without proportionally increasing the overall cylinder dimensions, as the increased stroke is achieved through the eccentric motion rather than larger cylinder volume.

Inventive Principle:
Principle #35Parameter changes

3Volume of moving object

If the eccentricity of the crank shaft is increased to achieve miniaturization, then the compressor size is reduced, but the force on the crank shaft increases reducing reliability

Engineering Contradiction:
Improvecompressor sizeVSAvoidcrank shaft reliability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The annular partition plate is designed with stepped levels that pre-establish sealing zones at different radial positions. This preliminary structural arrangement ensures that as the eccentricity increases and the roller moves through its orbit, sealing contact is maintained at appropriate radial distances, preventing refrigerant leakage that would otherwise occur with high eccentricity designs.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3486489B1Pump body component with crank shaft and compressor
Publication Date: 2021.08.18 ZHUHAI GREE REFRIGERATION TECH CENT OF ENERGY SAVING & ENVIRONMENTAL PROTECTION
  • EP3486489B1 patent drawingFigure 1
  • EP3486489B1 patent drawingFigure 2
  • EP3486489B1 patent drawingFigure 3~4

AI summary

Disclosed is a crank shaft, including a central rotation shaft (1), a first eccentric component (2), a second eccentric component (3), a disc partition plate (18) and an annular partition plate (4), wherein the disc partition plate (18) is disposed between the first eccentric component (2) and the second eccentric component (3), and is integrally formed with the central rotation shaft (1), and the annular partition plate (4) is sleeved outside the disc partition plate (18). The crank shaft can prevent the occurrence of leakage between the partition plate and a roller while increasing an eccentricity of the crank shaft and improving operating performances of a compressor. Further disclosed are a pump body assembly having the crank shaft and a compressor.