Axial-Cavity-Free Pen-Type Bushing Securing for Wind Blades
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Solution Overview
Problem
Existing methods are not suitable for securing pen-type bushings in the blade root of a wind turbine blade, as they require additional axial cavities that are not compatible with this type of bushing.
Innovation Solution
A method involving a rod placement in the inner bushing channel, filling the space with a bonding compound, and using a sealing element to secure the bushing without an axial cavity, along with a cap to facilitate compound distribution and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an additional axial cavity is used to secure a bushing in a blade root, then the bushing can be accommodated, but the method is not suitable for pen-type bushings and requires additional structural complexity
Solution Approach 1:
The rod is placed inside the inner bushing channel, and the bonding compound flows through this nested structure. The rod acts as a temporary core around which the bonding compound is deposited, enabling the bushing to be secured without requiring an additional axial cavity in the blade root.
Solution Approach 2:
Instead of using an axial cavity (one-dimensional approach), the invention utilizes the inner bushing channel (already present in the bushing structure) and flows bonding compound through it. This transforms the problem from requiring additional blade root modification to utilizing the existing bushing internal geometry.
2Ease of operation
If the inner bushing channel is left open, then the bonding compound can flow through, but the inner thread is exposed and vulnerable to damage
Solution Approach 1:
The sealing element is installed in the inner bushing channel before the bonding compound is introduced. This preliminary action protects the inner thread from damage by the bonding compound while still allowing the compound to flow through the channel via the through-hole in the sealing element.
Solution Approach 2:
The sealing element acts as an intermediary component between the bonding compound and the inner thread. It has a through-hole that allows the bonding compound to pass through while preventing direct contact between the compound and the vulnerable inner thread, thus protecting it from damage.
3Ease of manufacture
If the bonding compound is applied without pressure, then the application is simple, but the bonding compound may not fill the entire space between the cavity and the bushing
Solution Approach 1:
A pressure difference is applied to the bonding compound during insertion, causing it to flow through the inner rod channel and fill the entire space between the cavity and the bushing. This pneumatic/hydraulic approach ensures complete filling without requiring complex manual application procedures.
4Stability of the object's composition
If the rod remains in the bushing during curing, then the bushing is held in position, but the rod occupies space needed for bonding compound flow
Solution Approach 1:
The sealing element is divided into two functional parts: a first section that seals the inner bushing channel, and a second section with a through-hole that allows bonding compound to pass through. This segmentation enables the sealing function while maintaining flow path openness.
Solution Approach 2:
The rod is temporarily placed in the inner bushing channel during bonding compound application, then removed after the compound has been introduced. This extraction of the rod after serving its purpose as a flow guide and temporary support allows complete bonding without permanent occupation of the channel space.
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
Enables secure placement and replacement of pen-type bushings in the blade root without axial cavities, ensuring effective bonding and alignment during curing.
Implementation Method 1
filling the space between the cavity and the bushing with a bonding compound to secure the bushing in the cavity thereby letting the bonding compound flow through the inner rod channel
Implementation Method 2
allowing the compound to cure until the bushing is secured in the cavity
Implementation Method 3
selecting and placing a sealing element in the inner bushing channel near the second outer end of the bushing for sealing off the inner bushing channel
Data Source
AI summary
The invention relates to a method for securing a bushing in a blade root of a wind turbine blade according to the preamble of claim 1. The method is known in the state of the art. The known method uses an additional cavity in axial direction of the blade root. The cavities in axial and radial direction are used for accommodation of a T-bolt type bushing. The known method is not suitable for pen-type bushing. The invention has for its purpose to provide a method, which is suitable for securing a pen-type bushing in the blade root, which method can also be used to replace an existing pen-type bushing in a blade root.