Machinery's Handbook, 31st Edition
2484 Ball and Roller Bearings 8) Groove radii. If groove radii are smaller than those specified in the bearing types cov ered, the ability of a bearing to resist fatigue is not improved: however, it is diminished by the use of larger radii. Ball Bearing Rating Life.— According to the Anti-Friction Bearing Manufacturers As- sociation standards the Rating Life L 10 of a group of apparently identical ball bearings is the life in millions of revolutions that 90 percent of the group will complete or exceed. For a single bearing, L 10 also refers to the life associated with 90 percent reliability. Radial and Angular Contact Ball Bearings: The magnitude of the Rating Life L 10 in millions of revolutions, for a radial or angular contact ball bearing application is given by the formula: (1) where C = basic load rating, newtons (pounds). See Formulas (2), (3a) and (3b) P = equivalent radial load, newtons (pounds). See Formula (4) Table 27. Values of fc for Radial and Angular Contact Ball Bearings cos d D m α Single Row Radial Contact; Single and Double Row Angular Contact, Groove Type a Double Row Radial Contact Groove Type Self-Aligning L P C 10 = 3 a k
Values of f c Metric b
Metric b
Inch c 3550 3730 3880 4020 4130 4220 4370 4470 4530 4550 4550 4530 4480 4420 4340 4250 4160 4050 3930 3800 3670
Inch c 3360 3530 3680 3810 3900 4000 4140 4230 4290 4310 4310 4290 4250 4190 4110 4030 3950 3840 3730 3610 3480
Metric b
Inch c 1310 1420 1510 1600 1690 1770 1940 2100 2260 2410 2550 2680 2790 2910 3000 3060 3110 3130 3140 3110
0.05 0.06 0.07 0.08 0.09 0.10 0.12 0.14 0.16 0.18 0.20 0.22 0.24 0.26 0.28 0.30 0.32 0.34 0.36 0.38
46.7 49.1 51.1 52.8 54.3 55.5 57.5 58.8 59.6 59.9 59.9 59.6 59.0 58.2 57.1 56.0 54.6 53.2 51.7 50.0 48.4
44.2 46.5 48.4 50.0 51.4 52.6 54.5 55.7 56.5 56.8 56.8 56.5 55.9 55.1 54.1 53.0 51.8 50.4 48.9 47.4 45.8
17.3 18.6 19.9 21.1 22.3 23.4 25.6 27.7 29.7 31.7 33.5 35.2 36.8 38.2 39.4 40.3 40.9 41.2 41.3 41.0 40.4
0.40 3070 a A. When calculating the basic load rating for a unit consisting of two similar, single row, radial contact ball bearings, in a duplex mounting, the pair is considered as one, double row, radial con- tact ball bearing. B. When calculating the basic load rating for a unit consisting of two, similar, single row, angular contact ball bearings in a duplex mounting, “face-to-face” or “back-to-back,” the pair is considered as one, double row, angular contact ball bearing. C. When calculating the basic load rating for a unit consisting of two or more similar, single angu- lar contact ball bearings mounted “in tandem,” properly manufactured and mounted for equal load distribution, the rating of the combination is the number of bearings to the 0.7 power times the rat- ing of a single row ball bearing. If the unit may be treated as a number of individually interchange-
able single row bearings, this footnote “C” does not apply. b Use to obtain C in newtons when D is given in mm. c Use to obtain C in pounds when D is given in inches.
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