Knowhow for all Bearing Locations
For more than 25 years now, Schaeffler Group Industrial (INA/FAG) has been engaged in the development and production of bearing supports for wind turbines and can provide solutions for all bearing locations in the rotor shaft, gearbox and generator as well as for wind tracking and rotor blade adjustment applications. As early as during the concept phase, detailed attention is paid to customer requirements. Bearing selection and documentation are backed up by sophisticated calculation methods. Products developed to a mature technical level are optimally matched to the particular task. Condition monitoring systems and lubricants as well as mounting and maintenance tools round off the range on offer. In this way, Schaeffler Group Industrial helps customers to achieve low operating costs for wind turbines.

High-performance bearing support concepts for the rotor shaft
The rotor shaft support is of central importance in wind turbines. This is where all the wind-induced forces and moments act directly. The rolling bearings are subjected to highly dynamic loads and operating conditions. In partnership with the customer, Schaeffler Group Industrial engineers develop the most efficient bearing support for each case – for the power trains of modern turbines with 220 kW output all the way through to the latest multi-megawatt class. Variants range from classical shaft bearing supports, via hub bearing supports through to single bearing concepts. Bearing housings calculated using state-of-the-art methods ensure the best possible support of forces and moments. In nearly all cases, development is undertaken to meet specific customer requirements and the housings are matched to the bearings used.

The ideal bearing support for any gearbox
Increasing megawatt ratings require larger and higher capacity gearboxes. Highly dynamic forces with extreme peak loads and minimal loads, sudden load reversals and widely differing operating temperatures are some of the challenges facing the bearing supports. The Schaeffler Group offers bearings with high static load safety factor and secure dynamic design according to international design guidelines such as AGMA6006-A03 and ISO 81400-4 respectively. New Schaeffler simulation calculations of the dynamic behavior of the power train lead to precise load models and thus enable more precise and reliable gearbox designs.

Long service life due to electrical insulation
In the design of bearings for generators, it is not only the speed, size and design that play an important role. Particular attention must be paid to the lubrication and protection against possible passage of current that can cause serious damage to the raceways of the bearing rings, resulting in enormous repair costs. The Schaeffler Group has therefore developed current-insulated bearings that protect the system efficiently and enable long service life to be achieved. Current-insulated bearings are available with coated rolling bearing rings and as hybrid bearings with ceramic rolling elements.

Wind tracking and blade adjustment
Wind turbines must be aligned optimally to the wind in order to prevent extreme loads and allow cost-effective operation. Schaeffler Group Industrial develops and manufactures slewing rings with outside diameters of up to 4,000 mm that ensure optimal rotor blade adjustment and wind tracking of the nacelle. Due to their design, these slewing rings can transmit radial and axial loads as well as tilting moments. Available as single or double-row four point contact bearings with or without gear teeth on the inner or outer rings, they enable precise angular adjustment under different loading conditions. If the rotor blade angle and nacelle are adjusted with the help of hydraulic drives, ELGES plain bearings with maintenance-free ELGOGLIDE® fabric are used. Corrotect® coating provides protection against corrosion.

Calculations of bearings through to complete gearboxes
The Schaeffler Group’s BEARINX® software can be used to model and calculate all bearing types, complex shafts, shaft systems and even complete gearboxes. The support reactions, the internal loads in the rolling bearings, the comparative stresses of the shafts and the most important parameters are calculated and presented in tabular and diagrammatic form. Obviously, the internal load distribution in the bearing is also precisely calculated – including the contact pressure taking into account the rolling element profile. Based on the individual rolling contact loads, BEARINX® determines the calculated bearing life more precisely than ever before. With BEARINX®-online Schaeffler Group customers can perform these complex calculations right in their office. For even more detailed analysis, FEM calculations can be used to determine the influence of the adjacent construction on the rolling bearings and vice versa. The CABA3D software enables the dynamic analysis of rolling bearings. Taking into account all the degrees of freedom, the force and movement curves of the rolling elements and rings are determined, from which results (e.g. for frictional energy) can be calculated for each time period. CABA3D can thus be used, for instance, to calculate the frictional energy transmitted and the acceleration behavior of the rolling elements when they enter the load zone.

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