Wind Turbine Hollow Shaft Coupling for High-Torque Alignment
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Solution Overview
Problem
Existing coupling assemblies for hollow shafts in wind turbines face challenges with deformation and misalignment due to high torque transmission, particularly in designs with small wall thickness, leading to statically over-determined systems and increased material usage.
Innovation Solution
A coupling assembly comprising a shrink ring, a coupling element, and multiple bolts that distribute torque through both frictional connections and bolted forces, reducing deformation and allowing for a more compact, aligned design by using a combination of first and second bolts to secure the rotational member to the hollow shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a shrink connection is used to transfer high torque in hollow shafts with small wall thickness, then torque transfer capability is improved, but deformation and run out of the main shaft increases
Solution Approach 1:
The coupling assembly is divided into multiple functional components: a shrink disc for friction-based torque transfer, a coupling element with annular groove for shaft engagement, and multiple bolts (first and second bolts) for mechanical fastening. This segmentation allows each component to perform its specific function optimally while distributing stresses throughout the assembly, preventing concentrated deformation in the hollow shaft.
Solution Approach 2:
The invention merges two different connection mechanisms into a single integrated coupling assembly: the shrink connection (friction-based) and the bolted connection (mechanical). This combination allows the shrink disc to handle torque transfer through friction while the bolts provide structural support and positioning, reducing the overall deformation of the hollow shaft compared to using either method alone.
2Power
If a shrink connection is used for torque transfer, then torque capacity is improved, but alignment of the gearbox becomes more difficult
Solution Approach 1:
The coupling element includes an annular groove that is pre-formed to match the outer diameter of the hollow shaft. This groove is designed with precise dimensional tolerances to ensure proper alignment before the shaft is inserted. The groove acts as a preliminary alignment feature that guides the shaft into the correct position, making subsequent gearbox alignment easier and more accurate.
Solution Approach 2:
The coupling element serves as an intermediary component between the hollow shaft and the shrink disc. It provides a precisely machined annular groove that interfaces with the shaft's outer diameter, acting as a mediator that ensures accurate alignment and positioning. This intermediary structure facilitates easier assembly and alignment compared to direct shrink connection methods.
3Stability of the object's composition
If additional bearings are added to support the gearbox, then system stability is improved, but device complexity increases
Solution Approach 1:
The coupling assembly is designed to perform multiple functions simultaneously: it provides torque transfer through the shrink disc, structural support through the bolted connection, and bearing support through the coupling element's integration with the main shaft bearing. By making the coupling assembly multi-functional, the need for separate additional bearings is eliminated, reducing system complexity while maintaining stability.
Solution Approach 2:
The invention merges the coupling function and the bearing support function into a single integrated assembly. The coupling element is designed to work in conjunction with the main shaft bearing, combining what would traditionally be separate components (coupling mechanism and bearing support) into one unified structure, thereby reducing the total number of parts and simplifying the system.
4Power
If traditional coupling designs are used, then torque transfer is achieved, but material usage increases
Solution Approach 1:
The coupling assembly segments the torque transfer function across multiple components with different material requirements. The shrink disc, coupling element, and bolts each use materials optimized for their specific function, rather than requiring the entire assembly to be made from high-strength materials. This segmentation reduces overall material usage while maintaining torque transfer capability.
Solution Approach 2:
The invention changes the connection parameters from traditional rigid mechanical coupling to a hybrid shrink-bolt connection. The shrink disc uses friction (a different physical mechanism) to transfer torque, allowing for more efficient material utilization. The bolted connection provides supplemental mechanical fastening with optimized bolt sizes and distributions, reducing the need for excessive material in the coupling structure itself.
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 effectively transfers large torques with reduced deformation and material usage, minimizing the risk of run-out and misalignment, and eliminates the need for additional bearings, resulting in a more efficient and cost-effective wind turbine design.
Implementation Method 1
apply the necessary pressure to transfer the loads in a friction connection
Data Source
AI summary
The present invention relates to a coupling assembly (1) for fixedly connecting a rotational member (2) to an end section (3) of a hollow shaft (4). It may e.g. be used for connecting the main shaft (4) of a wind turbine (28) to a planet carrier (2) of a coaxial planetary gear system. The coupling assembly (1) comprises a shrink ring (6) and a coupling element (7). The shrink ring (6) has an outer diameter corresponding to the inner shaft diameter (d) and a conical surface (14) for connecting the shrink ring (6) and the coupling element (7). The coupling element (7) comprises an annular groove (18) with a groove diameter corresponding to the outer shaft diameter (D) and a conical surface (20) matching the shrink ring (6). When in use, the hollow shaft (4) is arranged in the groove (18) and connected to the coupling element (7) by axially extending bolts (9). Hereby a torque can be transferred by both the shrink connection and the bolts fastened into the hollow shaft. The coupling element (7) preferably comprises an outer flange (26) to which the rotational member (2) can be fastened.