Schaeffler Group Industrial (INA/FAG) 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.
Wind turbines must adjust themselves to varying wind conditions. Tower and rotor blades need to be aligned in such a way that they can optimally utilize the wind conditions without being exposed to excessive stresses that might cause damage to them. So the tower and blade adjustment is vitally important for the cost-effective operation of wind turbines.
Blade adjustment (pitch bearings)
In order to control the power output of the wind turbine, the blade angle must always be optimally adjusted to the wind speed via the rotary motion of the blade bearing. Thus the blade adjustment controls the rotor speeds so as to enable power generation that is as consistent as possible. Very high loads occur in some instances from the dynamic load of the rotor blades. These loads must be transferred securely via the raceways and the screw connections of the blade bearings into the rotor hub. Single or double-row four point contact bearings with or without gear teeth on the inner or outer rings are used here.
Yaw bearing (azimuth bearing)
A slewing ring is also required in order to adjust the position of the nacelle to the wind direction. The wind load and the dynamic inertia forces are transferred via the raceways and the screw connections into the tower head. Single or double-row four point contact bearings with or without gear teeth on the inner or outer rings are used here.
Calculation ensures increased quality and reliability
Schaeffler Group Industrial has state-of-the-art software and calculation tools to assure the highest quality and reliability of its bearings and slewing rings. Schaeffler’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. 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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