Machinery's Handbook, 31st Edition
2486 Ball and Roller Bearings the bearing under consideration and is found by Formula (20); i is the number of rows of balls in the bearing; Z is the number of balls per row in a radial or angular contact bearing or the num- ber of balls in a single row, single direction thrust bearing; D is the ball diameter in millimeters (inches); and F r is the applied radial load in newtons (pounds). For radial and angular contact ball bearings with balls not larger than 25.4 mm (1 inch) in diameter, C is found by the formula: (2) and with balls larger than 25.4 mm (1 inch) in diameter C is found by the formula: (3a) (3b) where f c = a factor which depends on the geometry of the bearing components, the accu racy to which the various bearing parts are made and the material. Values of f c , are given in Table 27 i = number of rows of balls in the bearing α = nominal contact angle, degrees Z = number of balls per row in a radial or angular contact bearing D = ball diameter, mm (inches) The magnitude of the equivalent radial load, P , in newtons (pounds) for radial and angu lar contact ball bearings, under combined constant radial and constant thrust loads is given by the formula: (4) where F r = the applied radial load in newtons (pounds) F a = the applied axial load in newtons (pounds) X = radial load factor as given in Table 30 Y = axial load factor as given in Table 30 Thrust Ball Bearings: The magnitude of the Rating Life L 10 in millions of revolutions for a thrust ball bearing application is given by the formula: (5) where C a = the basic load rating, newtons (pounds). See Formulas (6) to (10) P a = equivalent thrust load, newtons (pounds). See Formula (11) For single row, single and double direction, thrust ball bearing with balls not larger than 25.4 mm (1 inch) in diameter, C a is found by the formulas: (6) (7) and with balls larger than 25.4 mm (1 inch) in diameter, C a is found by the formulas: L P C a a 10 3 = c m . , C f Z D a c 18 = 2 ⁄ 3 90 90 for for degrees degrees α = 0.7 , cos tan C f Z D 2 ⁄ 3 . 18 a c ! α α α = ^ h cos C f i = ^ Z D . . 07 h 18 2 3 ⁄ c α ) . 3647 ( cos C f i c ^ Z D 2 3 ⁄ metric . 07 . 14 α = h ( Z D inch . . ) 07 h cos C f i = ^ c 14 α 2 ⁄ 3 P XF YF r a = +
fZ D c 2 ⁄ 3
(metric) . 14
for
α =
90
, degrees
=
. 3647
C
(8a) (8b) (9a) (9b)
a
( ) C f Z D inch . a c 14 = 2 ⁄ 3
(metric)
cos
tan Z D . 14 2 ⁄ 3
. 07
for
90
, degrees
=
. 3647
C
f
h
^
α
α
α≠
a
c
. 14
= ^
cos
tan
(
inch
)
. 07
Z D 2 ⁄ 3
C f
h
α
α
a c
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