Pole-Gap Clamping Wedge for One-Side Rotor Bearing Maintenance
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Solution Overview
Problem
In medium-speed generators, replacing the output-side hollow shaft bearing requires supporting the rotor against gravity and magnetic force without detaching it from the stator, which is challenging, especially in large wind turbines, necessitating complex and heavy support devices or complete rotor removal.
Innovation Solution
A clamping wedge device with adjustable sliding ramps is inserted into the rotor's pole gap, allowing axial support and simplifying bearing maintenance by eliminating the need for radial screws or heavy bolted flanges, enabling access from one side and facilitating rotor repositioning without full removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heavy and stable support devices are used to hold the rotor aligned within the machine, then the rotor can be supported during bearing maintenance, but the device complexity and weight increase significantly
Solution Approach 1:
The support function is segmented into multiple wedge devices (typically three) distributed around the rotor circumference, each independently inserted into pole gaps. This distributes the support load and eliminates the need for a single complex heavy support structure, reducing overall device complexity while maintaining reliability
Solution Approach 2:
The support mechanism transitions from radial support (traditional bolted flanges or screws) to axial insertion followed by lateral spreading. The wedges are inserted axially into pole gaps and then spread laterally to contact the rotor inner surface, providing support through a different spatial dimension that simplifies the overall support device design
2Reliability
If radial screws or threaded rods are used to support the rotor, then the rotor can be held in position, but access around the generator is required and the device becomes more complex
Solution Approach 1:
The support mechanism transitions from radial support (traditional bolted flanges or screws) to axial insertion followed by lateral spreading. The wedges are inserted axially into pole gaps and then spread laterally to contact the rotor inner surface, providing support through a different spatial dimension that simplifies the overall support device design
Solution Approach 2:
The wedge device serves multiple functions: it provides rotor support, centers the rotor axially, and prevents radial movement. This multi-functionality eliminates the need for separate positioning and support mechanisms, reducing device complexity and improving ease of operation
3Ease of repair
If the rotor is completely removed from the electric machine to access bearings, then bearing maintenance can be performed, but productivity decreases and the process becomes more time-consuming
Solution Approach 1:
The wedge devices are inserted into the pole gaps before the bearing removal process begins, preliminarily securing the rotor in a supported and centered position. This preliminary support action enables subsequent bearing maintenance steps to be performed without needing to completely remove the rotor, thereby reducing maintenance time and improving productivity
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 clamping wedge device provides a compact, easy-to-use solution for supporting the rotor, allowing bearing replacement and transport without full rotor removal, reducing complexity and weight of support mechanisms.
Implementation Method 1
a plurality of pairs of sliding ramps, wherein the sliding ramps of a pair are displaceable relative to each other in the principal direction
Implementation Method 2
clamping wedge device for insertion into a pole gap of a rotor
Data Source
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AI summary
A clamping wedge device 10 for insertion into a pole gap of a rotor of an electric machine, comprising a first clamping part 12, a second clamping part 14, and a spreading part 16, wherein the first and second clamping parts 12, 14 and the spreading part 16 extend essentially in a principal direction R. Furthermore, a plurality of pairs of sliding ramps 181, 182 are provided, wherein the sliding ramps 181, 182 of a pair are displaceable relative to each other in the principal direction R, and depending on the relative position of the sliding ramps 181, 182 of a pair to each other, a distance orthogonal to the principal direction R between the first and second clamping parts 12, 14 is adjustable. This solution with the clamping wedge device 10 has the advantage of being relatively small, handy, and easy to use. It also only requires access from one axial side, which is the maintenance side anyway.