Page 32 - Y-bearing-units

Selection of Y-bearing

unit size

Load carrying ability and life Selecting the bearing unit
size using life equations
The size of a Y-bearing or Y-bearing unit required
for a specific arrangement is determined by To select a Y-bearing or a Y-bearing unit size,
the loads that will occur in the application and the basic rating life is typically calculated
the required life needed for the application. in accordance with ISO 281:2007. The equation
Variables known as load ratings are used in for ball bearings is
bearing calculations as a measure of the load
carrying ability: the basic dynamic load rating q C w 3
C and the basic static load rating C 0 . The basic L 10 = ––
< P z
dynamic load rating is based on specifications
determined in ISO 281:2007 while the basic
static load rating is based on specifications If speed is constant, the basic rating life
determined in ISO 76:2006. expressed in operating hours can be obtained
using

1 000 000 q C w 3
L 10h = ––––––––– ––
60 n < P z
or

1 000 000
L 10h = ––––––––– L 10
60 n
where
L 10 = basic rating life (at 90% reliability),
millions of revolutions
L 10h = basic rating life (at 90% reliability),
operating hours
C = basic dynamic load rating, kN
P = equivalent dynamic bearing load, kN
n = rotational speed, r/min

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