An engineering approach for the estimation of slewing bearing stiffness in wind turbine generators

Abstract

The stiffness of yaw and pitch slewing bearings has a critical influence on the structural behaviour of wind turbine generators. Thus, it is commonly required by designers for their simulations to estimate deformations and select the most suitable bearing for their working conditions in preliminary design stages. In this work, a design of experiments was carried out via finite element analysis to obtain the stiffness curves of all of the standard four‐point contact slewing bearings from the catalogues of manufacturers under radial, axial, and tilting loads. From these results, a set of simple formulas to calculate the ring deformations were adjusted. Combining them with contact deformation results obtained in previous work by the authors, a complete and efficient tool for slewing bearing stiffness estimation has been developed.

Bulletin of the Polish Academy of Sciences: Technical Sciences

“…. (11) If the constant c δ is introduced for the contact of three bodies with a spherical surface from point to point:…”

“…the greater the displacement of the inner race against the outer race, hence the greater axial deformation δa. The most appropriate way to determine the axial stiffness of (in this case) ball slewing rings is using finiteelement analysis [10,11]. However, this analysis needs to be verified by experimental measurement, given the correctness of their settings (boundary conditions, setting of contact parameters between the rolling elements and the race orbital paths) and the relevance of the results obtained.…”

Influence of the geometrical design on ball and crossed roller wire race bearing behavior under axial load

“…Regarding the dimensions of the cross section of the ring, it was considered unaproppiate to keep it constant for all cases, since the size of the cross section of the ring is usually related to the rolling element diameter Dw for regular bearings. The work developed by Heras in [11], proposed a general crossed section geometry for conventional bearings, dependant on Dw and the coeficients RL, RH, RLg, which were obtained from a deep study of catalogue geometries (see Fig. 2).…”

“…R is the radius of the wire housing, and its value is the radius of the wire minus 0.1 [mm] [12]. A 100% fill factor [11] indicates that the maximum allowable number of rolling elements were considered. Constant fill factor and constant Dpw also mean that the number of rolling elements varies if Dw changes.…”