Multi-Cylinder Rotary Compressor Bearing Layout for Shaft Deflection

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Solution Overview

Problem

Multiple cylinder rotary compressors with three or more compression mechanism sections face issues of rotating shaft deflection and increased complexity, leading to reduced compression performance and reliability due to the increased distance between bearings and complex synchronous rotation mechanisms.

Innovation Solution

A multiple cylinder rotary compressor design featuring a hermetic case with a rotating shaft supported by primary and secondary bearings, along with partition plates acting as bearings, reduces shaft deflection by distributing the eccentric sections evenly and simplifying the support mechanism, allowing for efficient compression and alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If three or more compression mechanism sections are arranged in the axial direction of the rotating shaft, then the discharge amount of the compressed gas refrigerant is increased, but the distance between bearings is increased causing large deflection in the rotating shaft

Engineering Contradiction:

Improvedischarge amount of compressed gas refrigerantVSAvoidcompression performance and reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The rotating shaft is divided into multiple sections with intermediate bearings positioned between the compression mechanism sections. This segmentation reduces the span between bearing supports, thereby reducing shaft deflection while allowing multiple compression sections to be arranged axially for increased discharge capacity.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the rotating shaft is divided in the shaft center direction with bearings disposed between compression mechanism sections, then the deflection or bend of the rotating shaft is reduced, but a complex mechanism is needed for synchronous rotation of divided shafts

Engineering Contradiction:

Improvedeflection reductionVSAvoidsynchronous rotation mechanism

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The divided rotating shaft sections are merged into a single integral shaft structure that passes through all compression mechanism sections. This eliminates the need for complex synchronous rotation mechanisms while maintaining reduced shaft deflection through proper bearing placement.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If the rotating shaft is divided and supported by multiple bearings, then the deflection is reduced, but the alignment of shaft centers during assembly becomes difficult with high accuracy requirements

Engineering Contradiction:

Improveshaft deflection controlVSAvoidshaft center alignment accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The compression mechanism sections are designed with standardized bearing support structures that can accommodate multiple compression sections with a single shaft. This standardization simplifies assembly and reduces the need for high-precision alignment of multiple shaft centers, while still achieving proper shaft support and deflection control.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

The design effectively reduces rotating shaft deflection, enhances compression performance, and improves reliability by simplifying the support mechanism while maintaining high accuracy in assembly and reducing operational costs.

Implementation Method 1

a roller rotating eccentrically within the cylinder chamber with the rotation of the rotating shaft

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

the rotating shaft is supported by a primary bearing and a secondary bearing positioned on both end sides of the compression mechanism body along an axial direction of the rotating shaft

Methodology Applied

Scientific EffectForce distribution: Force

Data Source

PatentUS10180271B2Multiple cylinder rotary compressor and refrigeration cycle apparatus

Publication Date: 2019.01.15 TOSHIBA CARRIER CORP

AI summary

The multiple cylinder rotary compressor includes a compressor body including a hermetic case, the hermetic case housing inside a rotating shaft, an electric motor section, and a compression mechanism body. The compression mechanism body includes at least three compression mechanism sections which stack with each other, partition plates between the corresponding adjacent compression mechanism sections, and a primary bearing and a secondary bearing supporting the rotating shaft on both end sides of the compression mechanism body. The compression mechanism sections include a cylinder forming inside a cylinder chamber, an eccentric section provided to the rotating shaft, disposed in the cylinder chamber, a roller fitted to the eccentric section, rotating eccentrically within the cylinder chamber, and a blade dividing the inside of the cylinder chamber into two. At least one partition plate constitutes a partition plate bearing supporting the rotating shaft.