Wind Turbine Gearbox Lubrication Using Gravity-Fed Siphons

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Solution Overview

Problem

Wind turbines, especially those in remote locations, face challenges in maintaining adequate lubrication of gearbox components during off-grid operations due to limited oil sump levels restricted by shaft sealings, which can lead to inadequate lubrication of all gearbox stages.

Innovation Solution

A lubrication system for wind turbine drive trains that includes an oil reservoir, supply valve, drain valve, and siphons, allowing for adjustment of internal oil levels in the gearbox during off-grid states, ensuring adequate lubrication by utilizing gravity-driven oil flow from elevated reservoirs to maintain oil levels in both stages of a two-stage gearbox.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the oil sump level is increased to provide adequate lubrication for all gearbox stages, then the lubrication coverage is improved, but the shaft sealings cannot retain oil above the lowest sealing point

Engineering Contradiction:
Improveoil quantityVSAvoidsealing reliability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The gearbox is divided into multiple stages, each with its own oil sump and sealing arrangement. The first stage has a first oil sump with a first sealing, and the second stage has a second oil sump with a second sealing. This segmentation allows each stage to have optimized oil levels independent of the others, resolving the contradiction between adequate lubrication coverage and sealing reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A transfer passage with a transfer opening acts as an intermediary between the first and second stages. This intermediary allows oil to be transferred from the first stage to the second stage while maintaining separate sealing systems, enabling the second stage to receive sufficient oil without compromising the sealing integrity of either stage.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Duration of action of moving object

If a larger oil reservoir is used to ensure sufficient lubrication during off-grid operations, then the lubrication duration is extended, but the device complexity increases

Engineering Contradiction:
Improvelubrication durationVSAvoidsystem complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The oil reservoir is merged with the gearbox structure, forming an integrated system. The reservoir includes a first portion and a second portion that correspond to the first and second stages, respectively. This merging eliminates the need for separate external reservoirs and complex distribution systems, extending lubrication duration while maintaining simplicity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The reservoir is designed with portions at different heights corresponding to the gearbox stages. The first portion is positioned at a higher level than the second portion, creating gravitational equipotential zones that allow oil to flow to each stage without requiring additional pumping mechanisms, thus extending lubrication duration without increasing complexity.

Inventive Principle:
Principle #12Equipotentiality

3Quantity of substance

If the oil level is maintained high to lubricate all stages, then the lubrication coverage is improved, but oil loss through sealings increases

Engineering Contradiction:
Improveoil distributionVSAvoidoil loss
Core Design Contradiction:
Quantity of substanceVSLoss of substance

Solution Approach 1:

The segmentation of the gearbox into stages with separate oil sums and sealings ensures that each stage maintains its own optimized oil level. This prevents oil from being forced above sealing points, thereby reducing oil loss while still ensuring adequate distribution to all stages through the transfer passage.

Inventive Principle:
Principle #1Segmentation

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

Ensures consistent lubrication of all gearbox stages during off-grid conditions, preventing wear and tear, and maintaining the reliability of wind turbine operations by providing sufficient lubrication without the need for auxiliary power.

Implementation Method 1

The siphon is configured to adjust an internal oil level in the gearbox in the off-grid state of the wind turbine

Methodology Applied
Scientific EffectSiphon effect: Syphon

Implementation Method 2

ensuring adequate lubrication by utilizing gravity-driven oil flow from elevated reservoirs

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3574212B1Lubrication system for a drive train of a wind turbine
Publication Date: 2022.10.26 SIEMENS GAMESA RENEWABLE ENERGY DEUT GMBH
  • EP3574212B1 patent drawingFigure 1
  • EP3574212B1 patent drawingFigure 2
  • EP3574212B1 patent drawingFigure 3

AI summary

A lubrication system for a drive train of a wind turbine comprises an oil reservoir (204) having an outlet (306), a supply valve (V3), a gearbox (103) having an oil inlet (308) and oil outlet (310), a drain valve (V1, V2) and a siphon (500). The oil reservoir (204) is coupled to the supply valve (V3) and the supply valve (V3) is coupled to the inlet (308) of the gearbox (103). The oil outlet (310) of the gearbox (103) is coupled to the drain valve (V1, V2) and to a first end of the siphon (500). The supply valve (V3) is configured to open in an off-grid state of the wind turbine and the drain valve (V1, V2) is configured to close in the off-grid state of the wind turbine. The siphon (500) is configured to adjust an internal oil level in the gearbox (103) in the off-grid state of the wind turbine.