Open Compressor Bearing Housing Surface Design for Lubrication

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In open type compressors, the lubrication of the lip seal and bearing member is insufficient due to the difficulty in introducing mist-like lubricant into the oil supply path, especially during low load operations where refrigerant circulation decreases.

Innovation Solution

The design includes a suction port with a tubular shape and an overlapping opening portion with the oil supply path, featuring a stepped configuration with a first surface, a connection surface, and a second surface to facilitate refrigerant stagnation near the oil supply port, preventing its introduction into the oil supply path.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a simple housing structure is used, then manufacturing cost is reduced, but lubrication of the lip seal and bearing member becomes insufficient

Engineering Contradiction:
Improvemanufacturing costVSAvoidlubrication sufficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The housing inner wall is segmented into multiple functional surfaces: a first surface that receives refrigerant flow, a connection surface that directs flow, and a second surface that facilitates stagnation near the oil supply path. This segmentation allows the simple housing structure to effectively guide refrigerant flow and ensure adequate lubrication without adding complex external components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection surface acts as an intermediary element between the first surface (refrigerant inlet) and the second surface (oil supply path vicinity). It mediates the refrigerant flow direction, ensuring that the refrigerant properly stagnates near the oil supply path opening to enable effective lubrication of the lip seal and bearing member.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the suction port is positioned away from the oil supply path, then structural simplicity is maintained, but refrigerant flow to the oil supply path is insufficient

Engineering Contradiction:
Improvestructural simplicityVSAvoidrefrigerant flow amount
Core Design Contradiction:
Device complexityVSQuantity of substance

Solution Approach 1:

Instead of moving the suction port closer to the oil supply path in a direct linear fashion (which would increase structural complexity), the invention uses the connection surface to redirect refrigerant flow in a different spatial dimension. The connection surface angles the flow to ensure proper stagnation near the oil supply path opening, achieving effective lubrication while maintaining structural simplicity.

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

3Loss of energy

If the refrigerant flows directly through the housing, then flow resistance is reduced, but lubrication of critical components becomes insufficient

Engineering Contradiction:
Improveflow resistanceVSAvoidcomponent lubrication
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The housing inner wall is designed with different local qualities: the first surface has a configuration to receive refrigerant flow, the connection surface has specific angular characteristics to direct flow, and the second surface is positioned to facilitate refrigerant stagnation near the oil supply path. This local quality variation ensures adequate lubrication at critical locations while maintaining overall flow efficiency.

Inventive Principle:
Principle #3Local quality

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 configuration ensures effective lubrication of the lip seal and bearing member by directing refrigerant and lubricant into the oil supply path, enhancing lubrication efficiency and preventing refrigerant leakage.

Implementation Method 1

after the refrigerant introduced from the suction port hits with the first surface, the refrigerant flows to the connection surface to reach the second surface. Therefore, the refrigerant easily stagnates in the vicinity of the connection surface on which an oil supply port is formed

Methodology Applied
Scientific EffectFluid flow and stagnation:

Data Source

PatentEP3315781B1Open type compressor
Publication Date: 2020.02.19 MITSUBISHI HEAVY IND THERMAL SYST
  • EP3315781B1 patent drawingFigure 1
  • EP3315781B1 patent drawingFigure 2
  • EP3315781B1 patent drawingFigure 3~4

AI summary

The present invention prevents a refrigerant including a lubricant from flowing without being introduced to an oil supply path. An open type compressor includes a compression mechanism, a drive shaft, a bearing which supports the drive shaft, a side wall in which a through-hole through which the drive shaft protrudes is formed, and a housing which includes a bearing holding portion (33) which protrudes in a tubular shape from the side wall to hold the bearing, a suction port (21) through which a refrigerant is introduced to an inside of the housing, and an oil supply path (81M) through which the lubricant is introduced from an outside of the bearing holding portion (33) in a radial direction to one side of the bearing in the axial direction. The bearing holding portion (33) includes a first surface (41) being provided at a position at which a refrigerant (G) introduced from the suction port (21) hits, a connection surface (43) which is connected to the first surface (41) and is oblique to the first surface (41) so as to extend away from the suction port (21) as going away from the first surface (41), a second surface (42) which is connected to the connection surface (43) and is oblique to the connection surface (43) so as to extend close to the suction port (21) as going away from the connection surface (43), and an opening portion (81a) of the oil supply path which is formed on the connection surface (43).