Rotary Compressor Discharge Flow Path to Eliminate Gas Guide Welding

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Solution Overview

Problem

Existing rotary compressors require a process of spot-welding a gas guide to the casing, increasing operational complexity and interfering with refrigerant flow.

Innovation Solution

A rotary compressor design that includes a partitioning member with an inclined and axial discharge flow path between the housing and casing, allowing refrigerant to swirl circumferentially and separate lubricant without a separate gas guide, using a casting surface to enhance separation efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a gas guide is used to form a gas flow path together with the casing inner surface and joined by spot welding, then the refrigerant flow can be controlled to separate lubricant, but the number of operation processes increases and the structure becomes more complex

Engineering Contradiction:
Improvelubricant separation efficiencyVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the gas guide function with the housing structure by forming the discharge flow path directly on the housing side surface. The inclined flow path is integrated into the housing body through casting or machining, eliminating the need for a separate gas guide component and its spot welding assembly, thus reducing structural complexity while maintaining lubricant separation functionality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the gas guide component from the system and replaces it with a discharge flow path formed directly on the housing. By taking out the separate gas guide and integrating its function into the housing structure, the invention reduces the number of parts and assembly operations while achieving the same refrigerant flow control and lubricant separation effects

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If a gas guide is spot-welded to the casing, then the refrigerant flow path can be defined, but the number of operation processes increases

Engineering Contradiction:
Improveflow path definitionVSAvoidassembly efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The discharge flow path is merged with the housing structure as an integrated component. The inclined flow path is formed directly on the housing side surface through casting or machining operations, combining what were previously separate components (housing and gas guide) into a single unit, thereby eliminating spot welding operations and reducing assembly process complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The separate gas guide component is taken out from the assembly and its function is transferred to the housing structure itself. By extracting the gas guide and integrating its flow path definition function into the housing, the invention eliminates the need for additional assembly operations such as spot welding, thus improving productivity

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If an inclined flow path is provided with an acute angle, then the refrigerant can swirl easily along the circumferential direction, but the flow path requires longer axial extension

Engineering Contradiction:
Improverefrigerant swirlingVSAvoidflow path length
Core Design Contradiction:
Ease of operationVSLength of stationary object

Solution Approach 1:

The patent utilizes the circumferential dimension of the housing side surface to create the inclined flow path. By extending the flow path in the circumferential direction rather than purely axially, the invention achieves effective refrigerant swirling and lubricant separation without requiring excessive axial length, thus resolving the contradiction between swirling effectiveness and compact design

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

The design facilitates smooth refrigerant swirling, reduces oil loss, and eliminates the need for spot-welding, thereby simplifying the process and improving lubricant separation efficiency.

Implementation Method 1

making the refrigerant flow along the inclined flow path (81) generates the flow of the refrigerant swirling along the circumferential direction of the casing (20) in the second space (24), which makes it possible to separate the lubricant contained in the refrigerant

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP4474651B1Rotary compressor and refrigeration apparatus
Publication Date: 2026.03.25 DAIKIN INDUSTRIES LTD
  • EP4474651B1 patent drawingFigure 1
  • EP4474651B1 patent drawingFigure 2
  • EP4474651B1 patent drawingFigure 3~4

AI summary

A housing (50) partitions an interior of a casing (20) into a first space (23) into which a refrigerant compressed by a compression mechanism (40) is discharged and a second space (24) provided between the housing (50) and a motor (30). The housing (50) has a discharge flow path (80) through which the refrigerant is discharged from the first space (23) toward the second space (24). The discharge flow path (80) includes an inclined flow path (81) that extends while inclining toward downstream in the direction of rotation of the motor (30).