Wind Turbine Pitch System Segmented Bearings
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Solution Overview
Problem
Existing wind turbine pitch systems are costly and complex due to the need for large, multi-row pitch bearings that must withstand fatigue loads and bending moments, with long studs being necessary for durability but increasing complexity and cost.
Innovation Solution
A pitch system comprising two separate bearings with an intermediate body between them, allowing for simpler and more cost-effective design, with the intermediate body reinforcing the second bearing and enabling longer stud lengths for improved fatigue behavior, and potentially incorporating an annular gear for the pitch drive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single large multi-row pitch bearing is used to withstand bending moments and fatigue loads, then the bearing can handle the loads, but the axial length becomes large and the construction becomes complex and costly
Solution Approach 1:
The single large multi-row pitch bearing is divided into two separate single-row bearings arranged in sequence along the axial direction. The first bearing is positioned nearer to the hub and the second bearing is positioned nearer to the blade root portion, with an intermediate body between them. This segmentation reduces the axial length and simplifies the construction of each individual bearing while maintaining the overall load withstanding capability through the combined system.
2Reliability
If long studs are used to attach the pitch bearing to withstand fatigue loads, then the fatigue resistance improves, but the overall complexity and cost increase
Solution Approach 1:
The attachment system is segmented into multiple shorter studs distributed across two separate bearings rather than using fewer long studs in a single bearing. The first bearing and second bearing each have their own set of studs attaching to the hub and blade root portion respectively, through the intermediate body. This segmentation allows for shorter stud lengths while maintaining adequate fatigue resistance through proper distribution and numbering of fasteners.
3Strength
If a single large pitch bearing is used, then the load capacity is sufficient, but the manufacturing cost and complexity increase significantly
Solution Approach 1:
The large pitch bearing is segmented into two smaller standard bearings that can be manufactured using conventional processes and then assembled together with an intermediate body. This segmentation allows the use of off-the-shelf standard bearings rather than custom-manufactured large multi-row bearings, significantly reducing manufacturing cost and complexity while maintaining the required load capacity through the combined arrangement.
Solution Approach 2:
An intermediate body is introduced between the two bearings to connect them and provide the necessary structural support. The intermediate body includes an hub-side part and a blade-side part that extend between the respective races of the first and second bearings, enabling the transmission of loads and moments while allowing each bearing to be a simpler, standard component.
4Strength
If the pitch bearing is positioned to withstand bending moments, then the bearing can handle wind loads, but the region remote from the hub experiences increased strain
Solution Approach 1:
The bearing system is segmented into two bearings positioned at different locations along the axial direction. The first bearing is positioned nearer to the hub where it can better withstand bending moments from wind loads, while the second bearing is positioned nearer to the blade root portion. This segmentation distributes the strain more evenly, with each bearing handling a portion of the loads appropriate to its position, reducing the peak strain on any single region.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a cost-effective and simpler pitch system with improved stiffness and reduced strain on bearings, allowing for adjustable dimensions and easier manufacturing, while enabling studs with better fatigue behavior and simpler drive toothings.
Implementation Method 1
each provided with an outer race, an inner race, and at least one row of rolling elements
Data Source
AI summary
A pitch system for a wind turbine rotor, comprising a first bearing and a second bearing, each provided with an outer race, an inner race, and at least one row of rolling elements, the first and second bearings being adapted to be arranged between a hub and a blade root portion or extender, to allow rotation of the blade with respect to the hub, wherein the first bearing is adapted to be arranged nearer to the hub than the second bearing in the axial direction, the pitch system further comprising an intermediate body arranged between the first bearing and the second bearing in the axial direction, said intermediate body comprising at least a blade-side part extending between the race of the first bearing that is associated with the blade and the race of the second bearing that is associated with the blade.