Segmented Pitch Ring Gear Wear Distribution
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Solution Overview
Problem
The annular gear in wind turbine pitch systems experiences significant wear due to heavy, alternating, and cyclical loads, leading to costly and complex maintenance, particularly in the 'below rated' pitch position where contact is concentrated on specific teeth.
Innovation Solution
The separation of the pitch bearing and annular gear into distinct components allows for a partial ring gear design, which can be more affordably manufactured and easily repaired by replacing or reconfiguring segments, reducing wear concentration and maintenance costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an integral annular gear is machined with the pitch bearing, then the structural integrity is improved, but the manufacturing cost and maintenance complexity increase
Solution Approach 1:
The annular gear is divided into multiple replaceable segments that can be independently manufactured and assembled onto the pitch bearing. This segmentation allows each segment to be manufactured separately using cost-effective processes while maintaining the overall structural integrity of the gear assembly.
Solution Approach 2:
The annular gear segments are extracted as separate replaceable components from the integral bearing structure. This extraction enables independent manufacturing, inspection, and replacement of gear segments without affecting the pitch bearing itself, reducing overall manufacturing costs and maintenance complexity.
2Strength
If an integral annular gear is used, then the structural integrity is improved, but the ease of repair deteriorates
Solution Approach 1:
The annular gear is segmented into multiple independently replaceable sections. When wear or damage occurs, only the affected segment needs to be removed and replaced, rather than replacing the entire gear assembly. This significantly reduces maintenance time and complexity while preserving the structural integrity of the remaining components.
Solution Approach 2:
Worn or damaged gear segments can be discarded and replaced with new or refurbished segments. The reusable segments can be recovered, refurbished, and reused, creating a sustainable maintenance cycle that reduces overall maintenance complexity and cost.
3Reliability
If induction hardening is applied to reduce wear, then the durability is improved, but the manufacturing cost increases
Solution Approach 1:
Instead of applying induction hardening to the entire annular gear, the hardening process is applied only to the specific contact zones of the gear segments that experience wear. This localized treatment reduces material costs and processing time while maintaining durability where it is most needed.
Solution Approach 2:
The gear is segmented so that hardening can be applied to individual segments during manufacturing or refurbishment. This allows for cost-effective application of hardening treatments only when and where necessary, rather than treating the entire gear assembly uniformly.
Data Source
AI summary
The invention relates to a wind turbine rotor comprising a hub, a plurality of blades, and at least one pitch mechanism for rotating at least one of the blades, each pitch mechanism comprising a partial ring gear, a pitch bearing, a pinion that is arranged to mesh with the partial or complete ring gear and a pitch motor arranged for driving said pinion, wherein the pitch bearing is mounted between the hub and a blade, and the ring gear is mounted on the hub or on the blade. The invention further relates to a method of repairing a partial or complete ring gear in a wind turbine rotor, the ring gear comprising a plurality of segments, the method comprising detaching at least a segment of the ring gear and attaching the ring gear in a modified configuration.