Wind Turbine Gearbox Axle Coating for Maintainable Plain Bearings

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Solution Overview

Problem

The maintenance of plain bearings in wind turbine gearboxes is complex and expensive due to the difficulty in replacing worn-out components, and existing solutions like roller and sliding bearings face issues with position loss and thermal stress during coating processes.

Innovation Solution

A thermal spraying process is used to apply a sliding layer directly onto the axle, which can include metallic alloys like aluminum-based, bismuth-based, or copper-based materials, with optional intermediate layers and embedded particles, allowing for easier maintenance and improved tribological performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If plain bearing bushings are shrunk onto the shaft or pressed into the planet gear, then the bearing provides adequate support, but the maintenance becomes complex and costly due to difficulty in replacing worn-out components

Engineering Contradiction:
Improvebearing supportVSAvoidmaintenance complexity
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The invention extracts the bearing function from a separate bushing component and integrates it directly into the shaft through a sprayed sliding layer. This eliminates the need for separate bearing bushings that are difficult to replace, allowing the bearing surface to be easily reapplied or replaced without removing the entire shaft or gear assembly.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The sliding layer is applied in advance during manufacturing or initial setup, creating a ready-to-use bearing surface. This preliminary application of the bearing material eliminates the need for complex installation procedures later, and allows for simpler maintenance by enabling direct reapplication of the sliding layer when wear occurs.

Inventive Principle:
Principle #10Preliminary action

2Ease of repair

If thermal spraying process is used to apply sliding layer, then the maintenance is simplified and position losses are eliminated, but thermal stress may be generated on the axle during coating process

Engineering Contradiction:
Improvemaintenance simplicityVSAvoidthermal stress on axle
Core Design Contradiction:
Ease of repairVSStress or pressure

Solution Approach 1:

The invention modifies the thermal spraying parameters to control the temperature profile during coating application. By adjusting parameters such as spray distance, coating speed, and material composition, the process achieves adequate bonding of the sliding layer while limiting thermal stress on the axle to acceptable levels.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If particles are embedded in the sliding layer, then the tribological performance is improved, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvetribological performanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention creates a composite sliding layer material that incorporates hard particles (such as ceramic or metallic particles) within a metallic or polymer matrix. This composite structure provides enhanced wear resistance and tribological performance while the thermal spraying process integrates both components in a single manufacturing step, avoiding the need for separate particle embedding operations.

Inventive Principle:
Principle #40Composite materials

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 approach simplifies maintenance by enabling easy removal of the axle, reduces position losses, and enhances lubrication, while minimizing thermal stress on the axle and improving the longevity of the bearing through a defined microstructure and better tribological properties.

Implementation Method 1

a sliding layer which is sprayed directly onto the shaft using a thermal spraying process or onto the intermediate layer with at least one further layer in between

Methodology Applied
Scientific EffectThermal spraying: Plasma Spray

Implementation Method 2

the particles flatten upon impact with the axle, aligning themselves in the direction of the gear's rotation

Methodology Applied
Scientific EffectParticle flattening and alignment: Impact Force

Implementation Method 3

This allows the lubricating layer components to exert their lubrication more effectively over a longer circumferential path

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3631203B1Wind turbine gearbox and method of manufacturing an axle for a wind turbine gearbox
Publication Date: 2022.03.09 MIBA GLEITLAGER AUSTRIA GMBH
  • EP3631203B1 patent drawingFigure 1
  • EP3631203B1 patent drawingFigure 2
  • EP3631203B1 patent drawingFigure 3~4

AI summary

The invention relates to a wind turbine transmission (8), in particular a planetary gearbox, comprising at least one gear (12), which is mounted on a shaft (15), a sliding layer (20) being arranged between the gear (12) and the shaft (15) for this purpose, which sliding layer is sprayed by means of a thermal spraying method directly onto the shaft (15) or, in the case of the interposition of at least one further layer (21), onto the further layer (21).