Split Wind Turbine Blade Joint With Integrated Fitting Assembly

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Solution Overview

Problem

Existing methods for connecting wind turbine blade sections require a high number of parts and complex constructions, necessitating precise machining and complicating the manufacturing and joining process.

Innovation Solution

A wind turbine blade connection system with a reduced number of parts, featuring a single pair of abutting faces for milling, a fitting with restricted degrees of freedom, and a fastener system that allows external access and efficient load transfer, utilizing inserts with undulating surfaces and asymmetric joint design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple separate fittings and inserts are used to connect blade sections, then the joint can accommodate manufacturing variations, but the parts count increases and manufacturing complexity increases

Engineering Contradiction:
Improvetolerance to manufacturing inaccuraciesVSAvoidparts count
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple separate fittings and inserts into a single integrated fitting that connects two blade sections. This single fitting includes integrated features for receiving fasteners, abutting against blade ends, and providing structural support, thereby reducing the parts count from multiple components to one unified component while maintaining the ability to accommodate manufacturing variations through its integrated design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single fitting performs multiple functions simultaneously: it provides structural support between blade sections, receives and positions fasteners, abuts against blade end surfaces, and accommodates manufacturing tolerances. This multi-functional design eliminates the need for separate dedicated components for each function, reducing overall complexity while maintaining robustness.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of manufacture

If multiple abutting faces are milled on separate fittings and inserts, then the joint can be assembled with proper alignment, but the manufacturing time and cost increase

Engineering Contradiction:
Improvemilling operations requiredVSAvoidalignment accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent consolidates multiple abutting faces that would traditionally be milled on separate fittings and inserts into a reduced number of abutting faces on the single integrated fitting. This reduction in the number of milled surfaces directly decreases manufacturing time and cost while the strategic placement of these faces ensures proper alignment during assembly.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single fitting is designed with pre-positioned abutting faces and fastener receiving features that guide proper alignment during assembly. The fitting's geometry inherently provides alignment cues that ensure correct positioning without requiring extensive precision milling of multiple separate components.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If a separate fitting with clearance holes is used, then the fitting can accommodate positioning variations, but the fitting has excessive freedom of movement and reduces joint stability

Engineering Contradiction:
Improvefreedom of movementVSAvoidjoint stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent employs a dynamic fastening system where the single fitting transitions from a state of controlled freedom of movement during assembly to a fixed, stable state once fasteners are installed. The fitting's design allows for positioning adjustments during assembly but provides rigid structural connection when fastened, optimizing both adaptability and reliability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The single fitting acts as an intermediary component that mediates between the blade sections and fasteners. It provides a stable mounting surface for fasteners while accommodating positioning variations, and when fastened, it creates a rigid connection that transfers loads effectively between blade sections, ensuring joint stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Strength

If multiple fasteners and nuts are required for connecting fittings, then the joint strength increases, but the accessibility for tool placement decreases

Engineering Contradiction:
Improvejoint strengthVSAvoidtool accessibility
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent integrates multiple fastener receiving features into the single fitting, allowing multiple fasteners to be positioned and secured from accessible locations. The fitting's geometry is designed to accommodate multiple fasteners while maintaining external accessibility for tool placement, eliminating the need for internal nut installation that would restrict tool access.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Instead of requiring nuts to be placed inside the fitting (which would restrict tool access), the patent inverts the fastening approach by designing the fitting to receive fasteners from the outside or in externally accessible positions. This reversal of the traditional fastening sequence improves tool accessibility while maintaining joint strength through multiple fasteners.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP4004363B1Connection for split wind turbine blade
Publication Date: 2026.04.15 VESTAS WIND SYSTEMS AS
  • EP4004363B1 patent drawingFigure 1
  • EP4004363B1 patent drawingFigure 2
  • EP4004363B1 patent drawingFigure 3~4

AI summary

A wind turbine blade comprising: a first blade portion having a shell that defines a suction side, a pressure side, a leading edge, and a trailing edge of the blade, the first blade portion further including a first blade portion end surface at one end of the first blade portion; a second blade portion having a shell that defines a suction side, a pressure side, a leading edge, and a trailing edge of the blade, the second blade portion further including a second blade portion end surface at one end of the second blade portion, wherein the first blade portion and the second blade portion are configured to be coupled together at the first and second blade portion end surfaces; and a connection joint for coupling the first and second blade portions together, wherein the connection joint includes: a first insert embedded in the first blade portion; a fitting integral with the first insert and projecting from the first blade portion end surface toward the second blade portion end surface; a second insert embedded in the second blade portion; and a fastener arranged to fasten the second insert to the fitting.