The wind power industry has established itself with sophisticated technologies. Efficiency and reliability details are being optimized: Design space and weight have to be reduced; components have to demonstrate greater performance and reliably withstand ever increasing requirements in operation.
Compact bearing design for maximum design space use, ever increasing bearing reliability for high machine availability and digital services for predictive maintenance are only some of the topics that Schaeffler will be presenting at the WindEnergy trade show. As one of the world’s leading rolling bearing manufacturers, Schaeffler has produced bearing supports for wind turbines for more than 30 years and works closely with customers and suppliers throughout the process chain, all the way to volume production. The company’s systems expertise is expanded further and further through the intelligent application of various development tools and methods, e.g. FEA, dynamic simulation, coordinated validation testing and the analysis of the entire drive train. This leads to continuously developed and coordinated solutions for all wind turbines.
FAG spherical roller bearings: Optimized for rotor shafts
The force of the wind has a direct impact on the bearing supports of rotor shafts. That is why Schaeffler has optimized its spherical roller bearings by means of an entire set of measures. The result is spherical roller bearings with a revised micro and macro geometry, optimized for use as locating bearings. The development of an asymmetrical spherical roller bearing represents yet another step towards more robustness, particularly by reducing wear. It increases axial load carrying capacity while also reducing vibrations in the drive train. The reason for this is the asymmetrical bearing design with a greater contact angle on the row of bearings supporting the axial load and a flatter contact angle on the row of bearings that mainly support radial loads.
FAG flange bearing unit: compact and easy to install
Schaeffler is presenting a compact flange bearing unit for single-bearing systems used to support the rotor: Sealed and greased, the space-saving and pre-assembled rotor bearing unit is flanged onto both the inner and the outer ring. The double-row tapered roller bearing unit supports all forces and torques, thus permitting a compact drive train design. “Astraios” has assisted with the development of this flange bearing unit: Findings from test runs from the past five years on Schaeffler’s in-house large-size bearing test rig have been coordinated closely with the simulation and calculation of the bearing unit. The resulting system expertise is used permanently to optimize components and technology so that we can offer our customers an optimum solution. Here Schaeffler increasingly depends on state-of-the-art heat treatment processes.
High capacity in the gearbox: Higher load ratings and reduced friction
A planet gear bearing support is an extremely challenging bearing position. It is where high radial loads occur that must be supported by the bearing with limited design space and relatively thin-walled planet gears. This is something FAG’s high capacity cylindrical roller bearing can do. Particularly when used as a direct bearing support, it permits a much better design space utilization than comparable standard bearings.
White etching cracks: Feared, but preventable
A phenomenon having a negative impact on the reliability of bearings is the so called “white etching cracks” (WEC). For an efficient and economical reduction of these microstructure changes in the material, Schaeffler through hardens the bearings and coats rings and rolling elements with Durotect B. Damage caused by WEC has occurred in less than 0.01 percent of the more than 750,000 bearings of this type that have been produced by Schaeffler since 2005 for use in bearing positions affected by WEC. Schaeffler was the first bearing manufacturer able to reproduce the much feared WEC damage on a test stand and will continue to research their root causes in order to develop suitable countermeasures.
Condition monitoring as plain text
Schaeffler’s new digital services are now also available for wind turbines. Modular sensor systems in the drive train, specially adapted for low frequencies, for instance, are now used to acquire condition information during operation by means of vibration measurement which is processed in real time. Operators and maintenance personnel can use the digital “automated rolling bearing diagnosis” service to monitor the condition of individual bearings and entire units worldwide via an Internet connection. They receive a plain text message regarding the analyzed damage and are able to rely on the support of Schaeffler’s experts via remote analysis.
Calculation of remaining life
In addition, Schaeffler will be presenting a system for calculating the nominal remaining life of rolling bearings based on real load spectra. If wind power plant operators know at any given time what the remaining life is for each bearing in each turbine, they can consolidate and schedule maintenance work and thus ensure a favorable effect on the cost of energy. Sending data to the Schaeffler Cloud ensures that the latest calculation and analysis algorithms, greater calculation performance and more analysis options are available to operators through their links to other machine and sensor data.