Wind Turbine Main Shaft Fixture With Adjustable Mandrels
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Solution Overview
Problem
Existing main shaft fixtures for wind turbines require halting the turbine to fix the main shaft, are inflexible regarding shaft geometry, and necessitate separate facilities for self-hoisting cranes, leading to operational losses and increased maintenance costs.
Innovation Solution
A main shaft fixture with at least three radial displaceable pressure mandrels, equipped with tap shoes, that can be moved between passive and active positions, allowing for flexible fixation of main shafts with different geometries without halting the turbine, and incorporating facilities for self-hoisting cranes and lightweight cranes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional main shaft fixture is used to fix the main shaft during installation and repair work, then the main shaft can be firmly held, but the turbine must be halted and the rotor locked, causing operational losses
Solution Approach 1:
The fixture employs radial displaceable pressure mandrels that can be dynamically adjusted between active and passive positions. The pressure mandrels are displaceable radially outward to engage with the main shaft when fixation is needed, and can be retracted when not needed, allowing the turbine to operate without halting for fixture installation or removal.
Solution Approach 2:
The fixture is pre-installed on the nacelle structure before the main shaft is inserted. The pressure mandrels are positioned in advance so that when the main shaft is in place, the mandrels can be quickly displaced radially outward to engage with the shaft surface, enabling rapid fixation without turbine shutdown.
2Reliability
If a traditional main shaft fixture is used, then the main shaft can be fixed, but the fixture is inflexible regarding different shaft geometries, requiring multiple different fixtures
Solution Approach 1:
The fixture is designed with pressure mandrels that can be radially displaced to contact the main shaft at different radial positions. The tap shoes on the pressure mandrels can engage with various shaft geometries including cylindrical and conical shapes, making a single fixture design universal for multiple shaft types without requiring geometry-specific fixtures.
Solution Approach 2:
The radial displaceability of the pressure mandrels allows them to adapt to different shaft diameters and geometries. By adjusting the radial position of each pressure mandrel independently, the fixture can accommodate variations in shaft geometry while maintaining reliable fixation.
3Ease of operation
If separate facilities are provided for self-hoisting cranes, then crane mounting is possible, but this increases device complexity and maintenance costs
Solution Approach 1:
The fixture integrates crane mounting facilities directly into its structure. The same radial displaceable pressure mandrels that secure the main shaft also serve as mounting points for self-hoisting cranes. The tap shoes and pressure mandrel mechanisms are dual-purpose: they fix the main shaft and provide anchoring points for crane operations, eliminating the need for separate crane mounting facilities.
Solution Approach 2:
The pressure mandrels and tap shoes perform multiple functions: they secure the main shaft during installation and repair, and simultaneously provide mounting facilities for self-hoisting cranes and lightweight cranes. This multi-functionality reduces overall device complexity while maintaining full operational capability.
Data Source
AI summary
A main shaft fixture for fixing a main shaft on a wind turbine during installation and repair work on heavy parts of the wind turbine nacelle, in the case where the fixture is formed of several sections for mounting on stable structural parts in the nacelle, including the nacelle's bottom frame. The main shaft fixture has adjustable pressure mandrels with tap shoes, which cause the fixture to be usable regardless of the turbine main shaft geometry, such that it can be mounted without fixing the rotor. The main shaft fixture also has facilities for mounting of a lightweight crane and a self-hoisting crane with a ground-based winch, respectively, as well as a rotor lock which, in combination with actuators of the main shaft fixture, enables the main shaft and the main shaft bearing to be sufficiently displaced vertically from its bearing in the nacelle to service or replace the bearing.