Wind Turbine Main Shaft Assembly for Accurate Deflection Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wind turbine systems face challenges in accurately measuring deflection of the main shaft due to movement of the main bearing housing and differences in material response to loads, leading to reduced fidelity of bending moment measurements.
Innovation Solution
A shaft assembly with a non-loadbearing inner body within the shaft body, where sensors are coupled to the inner body to detect deflection without being load-bearing, maintaining synchronized rotation and providing physical separation to enhance measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are secured to the main bearing housing to detect shaft deflection, then deflection measurement is enabled, but measurement accuracy deteriorates due to housing movement under load
Solution Approach 1:
The shaft is divided into two separate bodies: an outer shaft body that carries the load and an inner shaft body that is non-loadbearing. Sensors are mounted on the inner body to measure deflection without being affected by load-induced movements of the outer body or bearing housing.
Solution Approach 2:
The inner non-loadbearing shaft body acts as an intermediary between the load-bearing outer shaft and the sensors. It provides a stable reference frame for sensor mounting that is isolated from the dynamic loads and movements of the outer shaft system.
2Measurement precision
If sensors are directed at a moving surface to measure deflection, then real-time measurement is achieved, but measurement accuracy deteriorates due to relative motion
Solution Approach 1:
The inner shaft body and sensors rotate together as a unified assembly at the same speed and in synchronization. This eliminates relative motion between the sensor and the measurement target, allowing accurate deflection measurement even during high-speed rotation.
Solution Approach 2:
The sensor and its mounting surface (inner shaft body) are in the same rotational reference frame, creating an equipotential condition where no relative motion occurs between them during rotation, thereby enabling stable and accurate measurements.
3Ease of manufacture
If the shaft body and inner body are made from different materials, then manufacturing flexibility is improved, but measurement accuracy deteriorates due to differential movement under load
Solution Approach 1:
The load-bearing function is extracted from the inner shaft body, making it non-loadbearing. This allows the inner body to be made from materials optimized for dimensional stability and sensor mounting, while the outer body uses materials optimized for load-bearing properties.
Solution Approach 2:
Different materials are used for different functional requirements: the outer shaft body uses materials with high strength and stiffness for load bearing, while the inner shaft body uses materials with high dimensional stability and low thermal expansion for accurate sensor reference.
Data Source
AI summary
A main shaft assembly of a wind turbine and method for manufacturing the same are provided. Accordingly, the main shaft assembly includes a structural/shaft body defining a cavity therein. The shaft body is configured to transmit a load of the wind turbine developed in response to the wind. An inner body is located within the cavity. The inner body is non-loadbearing with respect to the load. At least one sensor is coupled to the inner body and positioned within the cavity for detecting a deflection of the shaft body in response to the load.