Segmented Rotor Blade Bolt Pretensioning for Faster Assembly
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Solution Overview
Problem
Existing methods for joining rotor blade segments in wind turbines face challenges such as high friction losses, difficulty in precise adjustment of preload forces, and a time-consuming assembly process due to the complexity of components involved.
Innovation Solution
A wind turbine rotor blade design featuring sleeve-shaped pretensioning units mounted on connecting bolts, which include first and second pieces that engage in a form fit manner and can be axially moved apart to preload the bolts, ensuring a strong and precisely adjustable connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional joining methods with multiple components (lateral caps, wedges, transverse screws) are used to preload bolts, then the bolt connection can be preloaded, but friction losses occur, high forces are necessary, precise adjustment of preload forces is difficult, and the assembly process is time-consuming
Solution Approach 1:
The pretensioning unit is divided into a first piece and a second piece that can be moved relative to each other along the connecting bolt. This segmentation allows independent adjustment of each piece to achieve the desired preload force while simplifying the overall structure by eliminating lateral caps, wedges, and transverse screws.
Solution Approach 2:
The invention extracts and eliminates unnecessary intermediate components (lateral caps, wedges, transverse screws) from the pretensioning system. Only the essential first and second pieces remain, which directly engage with the connecting bolt to apply preload, thereby reducing device complexity and assembly time.
2Strength
If pressure pieces are arranged between rotor blade segments for each bolt connection, then the connection can be tightened, but the distance between adjacent pressure pieces is large, requiring larger bolts that can be loaded less, and the tightening process is time-intensive
Solution Approach 1:
The first and second pieces are designed to be movable relative to each other along the connecting bolt, allowing dynamic adjustment during assembly. This enables precise control of the preload force application process, speeding up tightening while maintaining connection strength.
Solution Approach 2:
The invention allows for precise adjustment of preload forces by changing the position of the first and second pieces relative to each other. This parameter control enables optimal preload values to be achieved without requiring larger bolts, thus maintaining connection strength while improving assembly productivity.
3Reliability
If conventional pretensioning methods are used, then bolts can be preloaded, but precise adjustment of preload forces is difficult
Solution Approach 1:
The first and second pieces are designed with features that allow preliminary positioning and adjustment before final tightening. This preliminary action enables precise setting of the preload force, ensuring reliable and repeatable connection quality.
Solution Approach 2:
The movable design of the first and second pieces provides inherent feedback during the pretensioning process, allowing operators to monitor and adjust the preload force in real-time. This feedback mechanism ensures precise achievement of target preload values, improving both reliability and measurement precision.
Data Source
AI summary
A wind turbine rotor blade is formed by at least two rotor blade segments, the segments being screwed together at respective connection ends of the segments via a plurality of connecting bolts, the connecting bolts being screwed into the first and second connection ends. A plurality of sleeve-shaped pretensioning units are arranged between the rotor blade segments, each of which is mounted on a corresponding connecting bolt. Each pretensioning unit includes a first and a second piece, wherein the first and the second piece engage each other in a form fit manner. The first and the second piece can be moved relative to each other along the corresponding connecting bolt by providing a force in an axial direction. The first and the second piece are axially pushed apart from each other along the corresponding connecting bolt against the respective connection ends, such that the corresponding connecting bolt is preloaded.