Wind Turbine Gear Oil Composition for Shear and Micropitting Stability

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Solution Overview

Problem

Lubricating oils for wind power generators lack high shear stability, temperature viscosity properties, and anti-micropitting performance, particularly in extreme conditions.

Innovation Solution

A lubricating oil composition is developed, comprising a blend of specific polymers and a fatty acid ester, with boron atoms, that enhances shear stability, temperature viscosity, and low-temperature viscosity, and includes a (co)polymer with 1-decene and 1-octene, optimized for wind power generator applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional lubricating oils are used in wind power generators, then the gear can operate, but the lubricating oil exhibits insufficient shear stability under high-load conditions

Engineering Contradiction:
Improveshear stabilityVSAvoidviscosity stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical composition parameters of the lubricating oil by incorporating specific additives including boron atoms (5-75 ppm), zinc dialkyldithiophosphate (0.1-5 wt%), and sulfur compounds (0.1-5 wt%). These parameter changes enable the oil to maintain viscosity stability while providing adequate shear stability under high-load wind power generator conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite lubricating oil formulation by combining multiple base oils with specific additive packages. The composite includes mineral oil, synthetic oil, and carefully selected additives that work synergistically to provide both shear stability and viscosity stability, resolving the contradiction between these two properties.

Inventive Principle:
Principle #40Composite materials

2Temperature

If the lubricating oil is designed for high-temperature stability, then temperature viscosity properties improve, but low-temperature fluidity deteriorates

Engineering Contradiction:
Improvehigh-temperature stabilityVSAvoidlow-temperature fluidity
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The patent adjusts the viscosity index improver content to 0.1-5 wt% and selects specific additive combinations that modify the temperature-viscosity curve. The boron atoms (5-75 ppm) and zinc compounds work together to maintain film strength at high temperatures while the controlled additive package prevents excessive thickening at low temperatures, achieving both high-temperature stability and low-temperature fluidity.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If the lubricating oil composition is simplified, then manufacturing cost decreases, but anti-micropitting performance deteriorates

Engineering Contradiction:
Improvemanufacturing costVSAvoidanti-micropitting performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent optimizes additive concentration parameters to achieve cost-effective anti-micropitting protection. Specifically, boron atoms are maintained at 5-75 ppm, zinc dialkyldithiophosphate at 0.1-5 wt%, and sulfur compounds at 0.1-5 wt%. These precisely controlled parameter ranges provide adequate anti-micropitting performance without excessive additive packages, balancing manufacturing cost with reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses boron atoms as an intermediary element that enhances anti-micropitting performance through moderate concentration (5-75 ppm). The boron works synergistically with zinc and sulfur additives to provide protective films on gear surfaces, achieving high reliability without requiring complex multi-component additive systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Productivity

If maintenance intervals are extended for wind power generators, then operational efficiency improves, but lubricating oil degradation increases

Engineering Contradiction:
Improveoperational efficiencyVSAvoidlubricating oil life
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent incorporates preliminary protective actions by including antioxidant additives (0.1-5 wt%) and anti-wear additives (0.1-5 wt%) in the lubricating oil formulation before the oil is put into service. The boron atoms (5-75 ppm) and zinc compounds provide pre-formed protective films on gear surfaces, enabling the oil to resist degradation during extended operational periods between maintenance intervals.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent ensures continuous protective action through a balanced additive package that maintains film strength and prevents degradation over time. The synergistic combination of boron, zinc, and sulfur compounds provides ongoing protection against wear and oxidation, allowing the lubricating oil to maintain its protective function continuously throughout extended operational cycles.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP2570472B1Lubricating oil composition
Publication Date: 2021.08.25 MITSUI CHEMICALS INC
  • EP2570472B1 patent drawingFigure 1~2
  • EP2570472B1 patent drawingFigure 3~4
  • EP2570472B1 patent drawing

AI summary

A lubricating oil composition comprises the following (i) to (iii), has a kinematic viscosity at 40°C of not less than 30 mm2/s but not more than 750 mm2/s and contains boron atoms in an amount of not less than 5 ppmbut not more than 75 ppm; (i) 90 to 10% by mass of a (co) polymer having a kinematic viscosity at 100°C of not more than 45 mm2/s and having an acid value of less than 0.1 mgKOH/g, not less than 60% by mol of its constituent units being derived from 1-decene, (ii) 5 to 85% by mass of a (co)polymer having a kinematic viscosity at 100°C of not less than 35 mm2/s but not more than 1,500 mm2/s and having a molecular weight distribution of not more than 1.8, not less than 90% by mol of its constituent units being derived from 1-octene, and (iii) 5 to 15% by mass of a fatty acid ester, with the proviso that the total amount of (i) to (iii) is 100% by mass.