Circular Collar Alignment for Wind Turbine Blade Root Ovalisation

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Solution Overview

Problem

Wind turbines face mechanical issues due to blade root ovalisation, leading to misalignment and potential failure of stay bolts, as current construction methods fail to maintain a circular shape, resulting in reduced durability and increased risk of untimely bolt failure.

Innovation Solution

A wind turbine system featuring a circular collar orthogonal to the mounting surface, which aligns blade root bushings with hub-side apertures, preventing direct contact and maintaining the circular shape of the blade root, thereby reducing ovalisation and ensuring accurate alignment and load transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a jacking mechanism is used to maintain a circular blade root shape during mounting, then alignment accuracy is improved, but the system complexity increases and the circular shape cannot be maintained after jacking force is removed

Engineering Contradiction:
Improvealignment accuracyVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The circular collar is pre-installed on the hub-side body before blade mounting operations. This preliminary placement establishes the reference circular geometry that guides the blade root bushings into proper alignment, eliminating the need for complex jacking mechanisms during the actual mounting process

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The circular collar acts as an intermediary element between the hub-side body and the blade root bushings. It provides a stable circular reference surface that mediates the alignment process, allowing accurate alignment without requiring complex active control systems or jacking mechanisms

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If stay bolts are used to mount the blade root, then connection strength is improved, but misalignment causes direct contact between bolts and root components leading to reduced durability

Engineering Contradiction:
Improveconnection strengthVSAvoiddurability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The circular collar serves as an intermediary alignment reference that ensures stay bolts are properly positioned relative to the blade root bushings. By providing a precise circular geometry, it prevents misalignment that would cause bolts to contact root components directly, thereby maintaining both connection strength and durability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the geometric parameter reference from the potentially ovalised blade root to the precisely circular collar. This parameter change ensures that the stay bolts are positioned with correct radial alignment, preventing harmful contact stresses while maintaining the required connection strength

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2888473B1A system and method to provide for accurate alignment when mounting a wind turbine blade
Publication Date: 2018.11.28 LM WIND POWER INT TECH II APS
  • EP2888473B1 patent drawingFigure 1
  • EP2888473B1 patent drawingFigure 2
  • EP2888473B1 patent drawingFigure 3~4

AI summary

A system and method of mounting a wind turbine blade is described, designed to aid in the guiding and alignment of wind turbine blade roots with hub-side components, e.g. a blade pitch system. Furthermore, the system is operable to reduce the effect of blade root ovalisation. At least one circular collar is provided which can bear against at least a section of the mounting elements, e.g. blade root bushings, projecting from the root end of a wind turbine blade. The collar acts to absorb the forces pushing the blade root towards an oval shape, thereby providing for improved handling of blade root ovalisation and ensuring accurate radial alignment of mounting elements, e.g. stay bolt bores and blade root bushings. Such an improved alignment system reduces the likelihood of bolt failure as a result of component misalignments.