Wind Turbine Blade Bearing Radial Offset Design
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Solution Overview
Problem
Wind turbines with smaller rotor blade diameters relative to blade length face increased longitudinal forces, leading to overloading of flange connections and bolts due to radial offsets, which can cause bearing deformation and reduced load-bearing capacity.
Innovation Solution
The implementation of a radial offset between the hub and rotor blade flange circumferences, combined with a four-point bearing design and extension portions in the bearing rings, reduces the crimping moment on flange connections by allowing the components to twist in the same direction, thereby increasing the load-bearing capacity and reducing material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the rotor blade diameter is selected very small for the respective blade length, then material usage is reduced and transport is easier, but longitudinal forces are increased leading to overloaded flange connections and bolts
Solution Approach 1:
The patent applies asymmetry by intentionally creating a radial offset between the hub flange and rotor blade flange, positioning them at different radial distances from the rotation axis. This asymmetric arrangement allows the flange connections to twist in the same direction, converting the harmful crimping moment into a more manageable load configuration that reduces stress on bolts while maintaining structural integrity with smaller blade diameters
2Device complexity
If a radial offset is present in the outer longitudinal force, then bearing design is simplified, but a crimping moment is generated that increases load on bearing and adjacent components
Solution Approach 1:
The patent converts the harmful crimping moment generated by radial offset into a beneficial effect. By deliberately designing the radial offset between hub flange and rotor blade flange, the system causes both components to twist in the same direction, which reduces the net crimping moment transmitted to the bearing and adjacent components, thereby transforming a potentially harmful force into a load-reducing mechanism
3Strength
If larger flange diameters are used to reduce longitudinal forces, then load distribution is improved, but material usage increases and transport becomes more difficult
Solution Approach 1:
The patent changes the radial position parameter of the flange connections by introducing a controlled radial offset between the hub flange and rotor blade flange. This parameter change allows the system to achieve optimal load distribution and reduced crimping moments with smaller flange diameters, thereby maintaining strength requirements while reducing material usage and improving transportability
Data Source
AI summary
The disclosure concerns a wind turbine, comprising: a hub with a hollow cylindrical region with a mean circumference UN; at least one rotor blade mounted rotatably on the hub, with a blade laminate which extends in the longitudinal direction of the rotor blade and at least in portions forms a hollow cylinder with a mean circumference UR; and at least one blade bearing for mounting the rotor blade on the hub, with a first bearing ring which is arranged on the hub side and connected by means of a first flange connection to a rotor hub flange formed on a rotor-blade side end portion of the hub, wherein the first flange connection has at least one hub longitudinal bolt which is arranged on a circumference UNB coaxially to the blade bearing; and a second bearing ring which is arranged on the rotor blade side and connected by means of a second flange connection to a rotor blade flange formed on a hub-side end portion of the rotor blade, wherein the second flange connection has at least one rotor blade longitudinal bolt which is arranged on a circumference URB coaxially to the blade bearing. The disclosure achieves the fundamental object in that a first radial offset V1 is formed between the circumference UN and the circumference UNB, and/or a second radial offset V2 is formed between the circumference URB and the circumference UR. In a further aspect, the disclosure achieves the fundamental object with a wind turbine rotor blade and a rotor blade bearing.