Centrifugal Compressor Thrust Bearing Clearance Control

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Solution Overview

Problem

The challenge in centrifugal compressors is ensuring precise control of the thrust surface clearance in dynamic pressure gas bearings, as inaccuracies can lead to reduced performance or failure of the bearing.

Innovation Solution

The solution involves an integrated structure of a fixing plate and a bearing support that limits the displacement of the radial bearing along the axial direction, ensuring accurate clearance control between the thrust bearings and the thrust disk.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the clearance of the gas bearing is controlled to be very small (several microns or tens of microns), then the precision and performance of the thrust bearing is improved, but the machining precision requirement becomes extremely high (sub-micron level) and the risk of bearing failure increases

Engineering Contradiction:
Improvethrust surface clearance controlVSAvoidmachining precision requirement
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces a dedicated thrust bearing support structure that acts as an intermediary component between the thrust bearing and the main bearing support. This support structure includes a thrust bearing seat with precisely controlled dimensions that directly determine the thrust surface clearance. By separating the clearance control function into this dedicated intermediary component, the machining complexity is distributed and the critical clearance control is achieved through the support structure's precise geometry rather than requiring sub-micron machining of all interacting surfaces.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If the thrust bearing clearance is controlled inaccurately, then the manufacturing process becomes easier, but the performance of the thrust bearing is reduced and the bearing may fail

Engineering Contradiction:
Improveclearance control processVSAvoidthrust bearing performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent implements preliminary action by pre-establishing the thrust surface clearance through the dimensions of the thrust bearing support structure during assembly, rather than relying on final clearance adjustment after all components are manufactured. The support structure is designed with predetermined dimensions that automatically establish the correct clearance when assembled, ensuring reliable thrust bearing performance while simplifying the manufacturing process by eliminating complex post-assembly clearance adjustment procedures.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If separate components are used for the fixing plate and bearing support, then the assembly flexibility is improved, but the assembling precision and efficiency of the thrust bearing is reduced

Engineering Contradiction:
Improveassembly flexibilityVSAvoidassembling precision and efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent merges the fixing plate and bearing support into an integrated thrust bearing support structure. This integrated structure combines the functions of fixing the radial bearing and supporting the thrust bearing into a single unified component with precisely controlled geometry. By merging these functions into one component, the patent achieves both high assembly efficiency and precise thrust bearing clearance control, as the integrated structure eliminates cumulative machining errors and alignment issues that would arise from assembling multiple separate components.

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

This approach improves the assembling precision and efficiency of the thrust bearing, reducing the risk of bearing failure and enhancing the operational stability of the centrifugal compressor.

Implementation Method 1

A dynamic pressure gas bearing has the advantages of high precision, low friction loss, long life, low vibration, no pollution and no need of providing a lubricating medium

Methodology Applied
Scientific EffectDynamic pressure gas bearing: Air Lubrication

Implementation Method 2

a radial bearing (8) is arranged between the fixing plate (51) and the outer circumferential face of the rotational shaft (1), and between the bearing support (52) and the outer circumferential face of the rotational shaft (1), to support a load working in a radial direction of the rotational shaft (1)

Methodology Applied
Scientific EffectRadial bearing support: Ball Bearing

Implementation Method 3

the first thrust bearing (10) is arranged in a first groove (31) formed at one end, away from a diffusion surface, of the diffuser (3), and a second thrust bearing (10') is arranged on one side, facing towards the diffuser (3), of the fixing plate (51)

Methodology Applied
Scientific EffectThrust bearing support: Ball Bearing

Data Source

PatentEP3904693B1Centrifugal compressor and air conditioning apparatus
Publication Date: 2025.06.04 GREE ELECTRIC APPLIANCE INC OF ZHUHAI
  • EP3904693B1 patent drawingFigure 1~2
  • EP3904693B1 patent drawingFigure 3~4
  • EP3904693B1 patent drawingFigure 5~6

AI summary

The present disclosure relates to a centrifugal compressor and air conditioning equipment. The centrifugal compressor includes: a main shaft (1); a diffuser (3), provided with a first thrust bearing (10) at one end away from a diffusion surface; a supporting assembly (5), provided with a second thrust bearing (10') at one end facing towards the diffuser (3); and a thrust disk (4), configured to rotate together with the main shaft (1), located between the diffuser (3) and the supporting assembly (5) along an axial direction and provided with a thrust portion (41), a clearance between one side of the thrust portion (41) and the first thrust bearing (10) and a clearance between the other side of the thrust portion (41) and the second thrust bearing (10') being limited through mutual abutting of the diffuser (3) and the supporting assembly (5). The centrifugal compressor is capable of accurately ensuring the clearance between the thrust bearings, ensuring the performance of the thrust bearings and improving the operational stability of the compressor.