Wind turbine design guideline DG03: yaw and pitch rolling bearing life

Original publisher: Golden, CO : National Renewable Energy Laboratory, 2009. OCLC Number: (OCoLC)495567169 Subject: Wind turbines -- Design and construction. Excerpt: ... The material factor f based on CVD 52100 steel material is given in Table 1. Compared with cm the values given in the standards [ 1, 3 ], these values have been extrapolated to accommodate large-diameter bearings ( i.e., values to 0.002, = Dcos / d. Because standard values of factor���m ) f are based on a raceway groove conformity of 0.52 ( f = raceway groove curvature radius / D ), cm and because yaw and pitch ball bearings frequently have a 0.53 conformity, Table 1 presents values of f adjusted for the latter ball-raceway conformity. To obtain f for 0.52 conformity, cm cm the f values of Table 1 must be multiplied by 1.172. cm Table 1. Values of f for Yaw and Pitch Ball Bearings ( f = f = 0.53 ) cm i o (�= 45�) f (�= 60�) f�cm cm 0.002 28.84 26.84 0.004 35.50 33.05 0.006 40.09 37.32 0.008 43.69 40.67 0.010 46.70 43.48 0.020 57.35 53.35 0.030 64.56 60.12 0.040 70.21 65.33 0.050 74.48 69.44 0.060 78.42 72.99 0.070 85.53 75.87 0.080 84.19 78.31 0.090 86.52 80.53 0.100 88.40 82.30, depend on the ball diameter. The equations for the basic dynamic axial load rating, Ca According to the load rating standards [ 1, 3 ], the capacity is reduced for balls larger than 25.4 mm ( 1 in. ), as indicated in equation 2. 0.7 2 / 3 1.4��( 2 )�n�C�3.647 f i cos Z D ta a cm For thrust roller bearings, the load rating standards provide the following equation for basic dynamic axial load rating. 7 / 9 3 / 4 29 / 27��( 3 ) C�f l cos Z D tan��a cm e The f values for thrust roller bearings are given in Table 2. Compared with the values provided cm in the standards [ 1, 4 ], these values have been extrapolated to accommodate large-diameter bearings ( i.e., values to 0.002, = Dcos / d ).���m 6