Wind Turbine Rotor Hub Blade Assembly Torque Management
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Solution Overview
Problem
The conventional blade-by-blade assembly method for wind turbines often results in significant load imbalances and excessive torque on mechanical components, leading to potential structural failures and increased costs due to the need for redesigning or using auxiliary equipment, with assembly windows restricted by wind speed limits.
Innovation Solution
A method that optimizes the blade assembly process by ensuring the gearbox experiences only positive torque, achieved by selecting appropriate hub rotation directions and wind speed limits for each step, reducing the need for oversized components and auxiliary tools, and allowing assembly at higher wind speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the conventional horizontal blade-by-blade assembly method is used, then the assembly process is simplified and the crane position remains fixed, but the gearbox is subjected to excessive negative torque that may exceed its design capacity
Solution Approach 1:
The patent inverts the conventional assembly sequence by attaching blades in a specific order (first blade at 3 o'clock, second blade at 9 o'clock, third blade at 6 o'clock) and rotating the hub in the opposite direction (counter-clockwise) compared to the conventional method. This inversion ensures that the gearbox experiences only positive torque or reduced negative torque throughout the assembly process, preventing torque overload while maintaining assembly simplicity.
2Ease of operation
If the hub is rotated to position each blade connection flange at the adequate position, then each blade can be attached sequentially, but significant load imbalances occur causing excessive torque on mechanical components
Solution Approach 1:
The patent applies preliminary action by pre-planning and executing the hub rotation and blade attachment sequence before actual assembly begins. The hub is rotated counter-clockwise to specific positions (120 degrees for the second blade, 240 degrees for the third blade) before each blade attachment, ensuring that the gearbox is never subjected to excessive negative torque. This pre-planned sequence prevents load imbalances from causing harmful forces.
3Ease of operation
If the assembly is performed with the hub rotated to specific azimuthal positions, then blade attachment is facilitated, but the assembly window is restricted by wind speed limits due to torque concerns
Solution Approach 1:
The patent changes the critical parameter of hub rotation direction from the conventional clockwise to counter-clockwise, and modifies the azimuthal positions for blade attachment. This parameter change fundamentally alters the torque characteristics during assembly, allowing the process to be performed at higher wind speeds without exceeding gearbox torque capacity, thereby expanding the assembly window and reducing time losses.
4Adaptability or versatility
If the gearbox is designed to support higher torque in both directions, then assembly flexibility is improved, but the cost and size of the gearbox increases
Solution Approach 1:
The patent exploits the asymmetric torque capability of modern gearboxes by designing an assembly sequence that asymmetrically loads the gearbox - specifically, ensuring that only positive torque or reduced negative torque is applied. This allows the gearbox to be sized for its optimal positive torque capacity rather than being oversized to handle equal negative torque, reducing gearbox size and cost while maintaining assembly flexibility.
Data Source
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AI summary
The present invention relates to a blade assembly method on a rotor hub of a wind turbine wherein the maximum torque supported by the gearbox is greater in one direction than in other (positive in the invention instead of negative) selecting an appropriate direction for rotating the hub and an appropriate side for connecting each blade.