Rotary Machine Bearing Drain Layout for Oil Leakage Suppression

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Solution Overview

Problem

In rotary machine systems, lubricating oil leaks from the electric motor bearing due to increased pressure, leading to cost increments from the necessity of additional suction devices to mitigate this issue.

Innovation Solution

The rotary machine system incorporates a lubricating oil discharge line configuration where the oil from the electric motor, compressor, and transmission is directed through a lower discharge line that creates a negative pressure in the electric motor bearing area, preventing leakage without the need for additional devices, by utilizing the flow of oil and gas to draw lubricating oil back into the oil tank.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a suction device is provided to suppress lubricating oil leakage, then the leakage problem is solved, but the system cost increases

Engineering Contradiction:
Improveleakage suppressionVSAvoidsystem cost
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the suction function into the existing oil tank rather than using a separate suction device. The oil tank is configured to directly suction lubricating oil from the bearing box through its structure, merging two functions (oil storage and oil suction) into one component, thereby suppressing leakage without increasing system cost

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The oil tank performs the suction function autonomously by its structural design, creating negative pressure within the bearing box to prevent leakage. This self-service mechanism eliminates the need for additional active suction devices, maintaining cost efficiency while solving the leakage problem

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If the motor is disposed at a position far from the oil tank, then the layout flexibility is improved, but the lubricating oil pressure in the bearing increases causing leakage

Engineering Contradiction:
Improvelayout flexibilityVSAvoidleakage prevention
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent uses pneumatic pressure differential created by the oil tank's suction capability to maintain negative pressure in the bearing box. This pneumatic mechanism allows the motor to be positioned far from the oil tank while still preventing leakage through pressure control, decoupling layout flexibility from leakage prevention

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 effectively suppresses lubricating oil leakage in the electric motor bearing while maintaining cost efficiency by eliminating the need for additional suction devices, ensuring reliable operation and efficient oil circulation.

Implementation Method 1

the oil from the electric motor, compressor, and transmission is directed through a lower discharge line that creates a negative pressure in the electric motor bearing area, preventing leakage without the need for additional devices, by utilizing the flow of oil and gas to draw lubricating oil back into the oil tank

Methodology Applied
Scientific EffectNegative pressure: Pressure Gradient

Data Source

PatentEP3872969B1Rotary machine system
Publication Date: 2024.05.01 MITSUBISHI HEAVY INDUSTIES COMPRESSOR CORP
  • EP3872969B1 patent drawingFigure 1
  • EP3872969B1 patent drawingFigure 2

AI summary

A rotary machine system includes a rotary electric machine, a rotary machine, a first supply line and a second supply line through which the lubricating oil is supplied to the rotary machine bearing, a first discharge line and a second discharge line through which the lubricating oil is discharged downward from the rotary machine bearing, and a lower discharge line through which the lubricating oil discharged from the first discharge line and the second discharge line flows toward a discharge destination. The lower discharge line has a first connecting portion connected to a lower end of the first discharge line and a second connecting portion connected to a lower end of the second discharge line, and extends such that the lubricating oil heads for the discharge destination through the first connecting portion from the second connecting portion.