Variable-Length Blade Bolts for Wind Turbine Pitch Bearing Load Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wind turbines with longer rotor blades face increased loading issues, particularly in high-speed wind conditions, leading to uneven load distribution across pitch bearings, which can result in damage and failure, and existing solutions like stiffener plates and rings are costly and ineffective.
Innovation Solution
A rotor blade assembly with varying-length blade bolts that distribute loads more evenly across the pitch bearing by using bolts and bolt holes of different lengths, along with spacers to accommodate these variations, ensuring even load distribution and reducing stress on the bearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If longer rotor blades are used to increase energy output, then energy output is improved, but loading on the pitch bearing increases leading to uneven load distribution and potential failure
Solution Approach 1:
The patent applies local quality by varying the length of individual blade bolts to create different stiffness characteristics at different locations around the pitch bearing. Longer bolts are used in regions requiring more flexibility while shorter bolts are used where stiffer connection is needed, thereby distributing loads more evenly across the pitch bearing races and improving reliability under increased loading from longer blades.
2Reliability
If stiffener plates and rings are added to distribute loads evenly, then load distribution is improved, but device complexity and cost increase
Solution Approach 1:
The patent changes the parameter of bolt length to achieve even load distribution without adding complex structural components. By adjusting the length parameter of existing blade bolts, the invention creates varying stiffness characteristics that distribute loads evenly across the pitch bearing, avoiding the need for additional stiffener plates and rings.
Solution Approach 2:
The invention extracts the load distribution function from separate stiffener components and integrates it into the blade bolt assembly itself. By making the bolts themselves the load-distributing elements through variable length design, the patent eliminates the need for additional stiffening components, thereby reducing device complexity.
3Ease of manufacture
If uniform-length blade bolts are used, then manufacturing is simplified, but load distribution across the pitch bearing becomes uneven
Solution Approach 1:
The patent applies local quality by varying the length of individual blade bolts to create different stiffness characteristics at different locations around the pitch bearing. Longer bolts are used in regions requiring more flexibility while shorter bolts are used where stiffer connection is needed, thereby distributing loads more evenly across the pitch bearing races and improving reliability under increased loading from longer blades.
Data Source
AI summary
The present disclosure is directed to a rotor blade assembly for a wind turbine that controls pitch bearing load distribution. The assembly includes a rotor blade having a body shell extending between a blade root and tip, a pitch bearing at an interface between the blade root and a hub of the wind turbine, and plurality of blade bolts coupling the blade root to the hub through the pitch bearing. The pitch bearing includes an outer bearing race and an inner bearing race rotatable relative to the outer race. Thus, in one embodiment, the blade bolts couple the blade root to the hub through the inner race of the pitch bearing. Further, each of the blade bolts has a first end and a second end defining a length therebetween and at least two of the blade bolts have varying lengths so as to distribute loads experienced by the pitch bearing.