Pitch Bearing Access Window for Replaceable Wind Turbine Pads
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Solution Overview
Problem
The high cost and difficulty of maintaining and replacing pitch bearings in wind turbine rotor blades, particularly due to their remote or offshore locations and the need for frequent but hazardous and expensive maintenance procedures, are exacerbated by the use of costly, long-lifetime bearing pads.
Innovation Solution
A rotor blade pitch bearing design featuring a carrier with annular bearing pad seats and a gripping assembly with an access window that allows easy exposure of bearing pads, enabling frequent replacement and reducing maintenance costs by using more economical bearing pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If bearing pads are made from robust polymer materials such as PEEK or include reinforcing material like glass fibre or carbon fibre to extend lifetime, then the lifetime of bearing pads is extended, but the cost of the bearing increases significantly
Solution Approach 1:
The patent applies this principle by using economical bearing pad materials that do not require expensive robust polymers like PEEK or reinforcing materials like glass fibre and carbon fibre. Instead, the bearing pads are designed to be replaceable at reasonable intervals, sacrificing material cost for overall system economy. The sliding part with access window enables easy replacement of these more economical bearing pads, making the disposable approach feasible.
2Ease of repair
If an annular or disc-shaped housing part is removed to expose bearing pads for maintenance, then bearing pads can be accessed, but the housing part has large diameter and is heavy and unwieldy to manipulate in confined hub space
Solution Approach 1:
The patent divides the housing into two separate parts: a stationary part and a sliding part. The sliding part can move independently along the rotor blade's longitudinal axis, allowing the access window to be positioned conveniently for maintenance personnel. This segmentation eliminates the need to remove a large, heavy annular housing component, as only the smaller sliding part needs to be manipulated to gain access to bearing pads.
Solution Approach 2:
The sliding part is designed to be movable rather than fixed, allowing it to slide along the longitudinal axis of the rotor blade. This dynamic feature enables maintenance personnel to position the access window at the most convenient location for bearing pad replacement, improving ease of operation during maintenance routines while maintaining secure access to the bearing pads.
3Loss of time
If bearing pads are designed for long lifetime to reduce maintenance frequency, then maintenance intervals are extended, but maintenance procedures become more hazardous and expensive when they are eventually required
Solution Approach 1:
The patent adopts economical bearing pad materials that are replaceable at reasonable intervals rather than designing for extended lifetime. This approach accepts more frequent maintenance but makes each maintenance event safer and less expensive through the easy-access design. The sliding part with access window enables quick bearing pad replacement without hazardous disassembly procedures.
Solution Approach 2:
The patent incorporates a wear indicator on the bearing pads that changes color or becomes visible when the bearing pad wears down to a critical threshold. This allows maintenance personnel to monitor bearing pad condition continuously and plan replacements proactively, avoiding emergency maintenance situations and enabling optimized replacement timing that balances maintenance frequency with operational needs.
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
This design allows for efficient and cost-effective maintenance of wind turbine rotor blades by enabling easy access and replacement of bearing pads, reducing the need for costly, long-lifetime materials and simplifying the maintenance process, thereby lowering operational expenses.
Implementation Method 1
The sliding part is arranged to slide relative to the pad carrier when the pitch system is actuated, and shall be understood to comprise a low-friction contact surface that lies against an annular arrangement of bearing pads
Data Source
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AI summary
Wind turbine rotor blade pitch bearing (1) for mounting a rotor blade (2) to a hub (3), comprising a carrier (10) with an annular arrangement of bearing pad seats (10S); a plurality of bearing pads (P), wherein a bearing pad (P) is arranged in each bearing pad seat (10S) of the carrier (10); and a gripping assembly (11A, 11B, 11D) for gripping the carrier (10), which gripping assembly (11A, 11B, 11S) comprises a sliding part (11A, 11B) arranged to lie against an annular arrangement of bearing pads (P) and further comprises an access window (11W) dimensioned to expose a bearing pad (P) when opened. The invention further describes a wind turbine with a number of such pitch bearings (1); and a method of performing a service routine on a wind turbine rotor blade pitch bearing (1).