Wind Turbine Blade Bearing With Variable Thickness Outer Ring
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Solution Overview
Problem
Wind turbines face reduced bearing lifetime due to unequal load distribution caused by large flap bending moments, leading to potential opening of blade bearings and uneven load distribution between inner and outer rings, which increases weight by requiring additional material for stiffness.
Innovation Solution
The outer or inner ring of the blade bearing features a circumferentially varying thickness, with increased thickness in high-load regions and reduced thickness in lower-load areas, allowing for enhanced stiffness without additional material, and can be produced using forging techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the outer ring size is increased to increase stiffness, then the bearing can support higher loads, but the weight of the bearing increases
Solution Approach 1:
The outer ring is designed with non-uniform thickness distribution, having greater thickness in high-load regions and reduced thickness in low-load regions. This local variation in geometry provides the necessary stiffness where required while minimizing material usage and weight in less critical areas, resolving the contradiction between stiffness and weight.
Solution Approach 2:
The outer ring transitions from a symmetric uniform thickness design to an asymmetric variable thickness design. The thickness varies circumferentially to match the asymmetric load distribution experienced by the bearing during operation, allowing optimized structural performance with reduced overall material quantity.
2Strength
If additional material is added to the outer ring to increase stiffness, then the bearing can withstand higher loads, but the amount of special steel increases
Solution Approach 1:
Instead of uniformly increasing material quantity throughout the outer ring, the invention applies material selectively in regions where it is most needed for structural stiffness. The variable thickness profile ensures that special steel is concentrated in high-stress zones while minimizing or eliminating excess material in low-stress zones, thereby maintaining required stiffness with reduced overall material consumption.
3Weight of stationary object
If the bearing is designed to be thin to reduce weight, then material usage decreases, but the stiffness is insufficient to support high loads
Solution Approach 1:
The bearing achieves an optimized balance between weight and stiffness through localized thickness variation. The outer ring is thin in regions where structural demands are lower, reducing overall weight and material usage. Simultaneously, the ring is thicker in high-load regions where stiffness is critical for supporting blade loads and resisting deformation, thus maintaining adequate stiffness without excessive weight.
Data Source
AI summary
Provided is a wind turbine including a hub and several blades rotatably attached to the hub by means of blade bearings including an inner ring coupled with the respective blade and an outer ring coupled with the hub, or vice versa, and rolling elements provided between the rings, wherein the outer ring or the inner ring has a cross section with a circumferentially varying thickness.