Wind Turbine Root Bushing Structure for Larger Pitch Bearing Contact

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Solution Overview

Problem

Existing root bushings for wind turbine rotor blades have limited contact area with the pitch bearing, resulting in insufficient force transmission and difficult positioning, which affects the reliability and efficiency of the friction connection between the blade root and the hub.

Innovation Solution

A root bushing design featuring a cylindrical body with a rectangular-shaped contact body, providing an increased contact area, a slanted extension portion with a reduced cross-section, and a central bore for a foam core or thread, enhancing the friction connection and connection to the composite material, while allowing for improved positioning and force transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the contact area between root bushing and pitch bearing is increased, then force transmission capability is improved, but the complexity of the root bushing structure increases

Engineering Contradiction:
Improveforce transmission capabilityVSAvoidstructure complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The root bushing is divided into two distinct parts: a cylindrical bushing body and a separate contact body with rectangular cross-section. The contact body is provided on a face of the bushing body and welded thereto, creating a segmented structure that increases contact area without requiring complete redesign of the entire bushing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The contact body is welded to the bushing body to form an integrated assembly. This merging of two components creates a unified structure that combines the load-bearing function of the bushing body with the enhanced contact surface of the contact body, improving force transmission while maintaining structural integrity.

Inventive Principle:
Principle #5Merging (Combining)

2Manufacturing precision

If the contact area between root bushing and pitch bearing is increased, then positioning accuracy is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvepositioning accuracyVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The root bushing is divided into two distinct parts: a cylindrical bushing body and a separate contact body with rectangular cross-section. The contact body is provided on a face of the bushing body and welded thereto, creating a segmented structure that increases contact area without requiring complete redesign of the entire bushing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The contact body features a rectangular cross-section with dimensions that differ from the cylindrical bushing body. By changing the geometric parameters (from circular to rectangular profile) and providing the contact body with larger cross-sectional dimensions, positioning accuracy is improved while the modular approach keeps manufacturing manageable.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the bending stiffness of the root bushing is increased, then force transmission reliability is improved, but the device complexity increases

Engineering Contradiction:
Improveforce transmission reliabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The contact body is welded to the bushing body to form an integrated assembly. This merging of two components creates a unified structure that combines the load-bearing function of the bushing body with the enhanced contact surface of the contact body, improving force transmission while maintaining structural integrity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bushing body maintains a cylindrical (curved) geometry while the contact body provides a rectangular interface. This combination of curved and straight geometric forms optimizes both structural performance and contact characteristics.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

The design increases the contact area and bending stiffness, enabling higher force transmission and easier positioning of the root bushing, thereby enhancing the reliability and efficiency of the friction connection between the root bushing and the pitch bearing.

Implementation Method 1

A connection between the root bushing and a pitch bearing of the hub is a friction connection. The quality of this connection is dependent on the contact area between the root bushing and the pitch bearing.

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the contact body is provided on a face of the bushing body and the bushing body and the contact body are welded together

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP2952734B1A root bushing for a blade root of a wind turbine rotor blade, a blade root, a wind turbine rotor blade and a wind turbine
Publication Date: 2021.04.07 SIEMENS AG
  • EP2952734B1 patent drawingFigure 1
  • EP2952734B1 patent drawingFigure 2~3
  • EP2952734B1 patent drawingFigure 4~5

AI summary

A root bushing for a blade root of a wind turbine rotor blade, a blade root, a wind turbine rotor blade and a wind turbine A root bushing (9) for a blade root (8) of a wind turbine rotor blade (5), comprising a cylindrical bushing body (10) and a flat contact body (18), wherein the contact body (18) is provided on a face (16) of the bushing body (10). This has the advantage that due to the provision of the contact body, the contact area between the root bushing and the pitch bearing is increased.