Wind Turbine Blade Root Coning Angle Design
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Solution Overview
Problem
Current wind turbine designs face challenges in achieving a uniform stress distribution at the blade-bearing joint and require complex assemblies to obtain an additional coning angle, leading to logistical and assembly issues, as well as potential stress imbalances and interference with the tower.
Innovation Solution
A wind turbine design that incorporates a blade with a bevelled joining area and a bearing system featuring a stationary and mobile ring, with attaching means that traverse through holes parallel to the blade's longitudinal axis and fixing surfaces on the bearing's front side, ensuring a balanced stress distribution and correct seating of fixing means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If an insert is used to obtain an additional coning angle, then the coning angle is achieved, but the device complexity increases and assembly becomes more difficult
Solution Approach 1:
The patent removes the intermediate insert component from the assembly and directly integrates the coning angle function into the blade root structure itself. The blade root is designed with a conical bearing surface that directly contacts the pitch bearing, eliminating the need for separate insert components and reducing assembly complexity while maintaining the required coning angle geometry.
Solution Approach 2:
The patent combines the coning angle function with the blade root structure by integrating the conical bearing surface directly into the blade root. This merging of functions eliminates the need for separate insert components and simplifies the overall assembly while achieving the same mechanical effect of the coning angle.
2Shape
If an insert is used to obtain an additional coning angle, then the coning angle is achieved, but the number of components and assembly steps increases
Solution Approach 1:
The patent extracts and eliminates the intermediate insert component from the assembly process. The blade root is designed with an integrated conical bearing surface that directly interfaces with the pitch bearing, reducing the number of components to be assembled and improving assembly productivity.
Solution Approach 2:
The coning angle geometry is pre-integrated into the blade root structure during blade manufacturing. This preliminary action ensures that the correct coning angle is built-in from the start, eliminating the need for additional assembly steps involving inserts and intermediate components.
3Shape
If holes are drilled at an angle to achieve coning angle, then the coning angle is obtained, but the stress distribution becomes uneven
Solution Approach 1:
The patent applies local quality by creating a specific conical bearing surface at the blade root with precise geometric properties. The conical surface is designed with a specific angle and surface quality that ensures uniform load distribution across the bearing contact area, while the fastening holes remain parallel to the blade axis for optimal stress distribution.
Solution Approach 2:
The patent uses asymmetry in the form of a conical bearing surface that is asymmetric relative to the blade axis. This conical geometry provides the necessary coning angle for tower clearance while maintaining symmetric fastening hole patterns parallel to the blade axis, ensuring uniform stress distribution through the symmetric fastening pattern.
4Shape
If nuts are fixed at the forward side of the bearing, then the additional coning angle is achieved, but the stress distribution becomes uneven due to incomplete seating
Solution Approach 1:
The patent eliminates the intermediate insert and the problematic nut fixation method. Instead, fastening means traverse the pitch bearing and are fixed at the rearward side (blade side), ensuring complete seating and uniform stress distribution while maintaining the coning angle through the conical bearing surface geometry.
Solution Approach 2:
The patent inverts the fixation location from the forward side of the bearing to the rearward side (blade side). This inversion ensures that the fastening means are properly seated and that stress is distributed uniformly across the blade root-bearing joint, while the coning angle is achieved through the conical bearing surface rather than the fixation method.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
Comprising: blades (2) with longitudinal axis (5) and joining area (7), featuring first surface (8) non perpendicular to longitudinal axis (5), and first holes (13) parallel to longitudinal axis (5); hub (3); bearing (4) with stationary ring (9) attached to hub (3) and mobile ring (10) with rear side (11) attached to the first surface (8), and front side (12); longitudinal attaching means (14) in the first holes (13) and traversing the bearing (4), surpassing the front side (12); fixing surfaces (15, 23, 24) at the area of the front side (12); and fixing means (16) resting against the fixing surfaces (15, 23, 24) to fix the attaching means (14), providing an additional coning angle with uniform distribution of stresses at the blade (2)-bearing (4) joint and with the appropriate seat for fixing means (16).