Compressor Oil Discharge Passage Geometry for Bearing Protection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In compressors, an excessively wide oil discharge passage can lead to excessive oil supply to the bearing, causing oil to be discharged with the refrigerant, while a narrow passage may clog with foreign substances, potentially damaging the bearing.

Innovation Solution

The oil discharge passage is positioned behind the oil supply hole in the rotation direction, with a width less than or equal to the supply hole, and features a chamfered portion to prevent foreign substance accumulation, ensuring easy discharge of substances through a tilted or extended passage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If the oil discharge passage width is increased to facilitate foreign substance discharge, then foreign substance discharge is improved, but excessive oil is supplied to the bearing causing oil loss

Engineering Contradiction:
Improveforeign substance accumulationVSAvoidoil discharge with refrigerant
Core Design Contradiction:
Object-generated harmful factorsVSLoss of substance

Solution Approach 1:

The patent optimizes the width parameter of the oil discharge passage to a specific range that balances two opposing requirements: it is wide enough to discharge foreign substances effectively but narrow enough to prevent excessive oil discharge. This parameter optimization resolves the contradiction by finding the optimal value that satisfies both conditions simultaneously.

Inventive Principle:
Principle #35Parameter changes

2Loss of substance

If the oil discharge passage width is narrowed to reduce oil supply to bearing, then oil loss is reduced, but foreign substances accumulate and clog the passage

Engineering Contradiction:
Improveoil discharge with refrigerantVSAvoidforeign substance accumulation
Core Design Contradiction:
Loss of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent determines the optimal width parameter for the oil discharge passage that prevents both excessive oil discharge and foreign substance accumulation. By carefully selecting this parameter within a specific range, the design achieves a balance where the passage is narrow enough to reduce oil loss but wide enough to allow foreign substances to pass through without clogging.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the oil supply hole size is increased to improve oil supply to bearing, then lubrication is improved, but foreign substance accumulation in the hole increases

Engineering Contradiction:
Improvebearing lubricationVSAvoidforeign substance accumulation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the foreign substance removal function from the oil supply hole by providing a separate oil discharge passage. This allows the oil supply hole to maintain a larger size for adequate lubrication while the separate discharge passage handles foreign substance removal, preventing accumulation in the supply hole.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The oil discharge passage acts as an intermediary channel that receives foreign substances from the oil supply system and transports them outside the bearing area. This intermediary structure allows the oil supply hole to focus on lubrication while the discharge passage handles contamination removal.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2980406B1compressor
Publication Date: 2018.05.30 DAIKIN INDUSTRIES LTD
  • EP2980406B1 patent drawingFigure 1
  • EP2980406B1 patent drawingFigure 2A~2D
  • EP2980406B1 patent drawingFigure 3A~3D

AI summary

On a drive shaft (23), formed is an oil discharge passage (71c, 72c, 73c) communicating with an oil supply hole (71a, 72a, 73a), having a flat surface or a recessed surface, and having a width that is less than or equal to a diameter of the oil supply hole (71a, 72a, 73a). A trailing edge of the oil discharge passage (71c, 72c, 73c) is displaced behind a trailing edge of the oil supply hole (71a, 72a, 73a) with respect to the rotation direction of the drive shaft (23). A foreign substance is prevented from being accumulated in the oil supply hole (71a, 72a, 73a) of the drive shaft (23) of the compressor, and therefore, damage to be done to the bearing (29a, 29b, 29c) is reduced.