certific at e - NOC international

112 KRW
Extended modified service life
The following restrictions on the valid range should be considered:
● a DIN ≤ 50
● if κ > 4, κ = 4 is used for calculation.
e C · C U
● if ——— > 5, a
P
DIN
is limited to 50
If the viscosity ratio is κ < 1 and the contamination factor e C ≥ 0,2, the factor κ = 1 1 may be used for calculation
if lubricants with EP additives are applied. The factor used should be limited to a DIN ≤ 3 or to the value of κ
calculated above
The following examples show how to use these factors.
Calculation example
The double row spherical roller bearing 23220EAS with the following parameters:
d = 100 mm C o = 654 kN
D = 180 mm C = 466 kN
B = 60,3 mm C U = 57,1 kN
is loaded as follows:
F r = 30 kN
F a = 19 kN
The constant speed is n = 500 rpm
From F a / F r = 0,633 > 0,35 with the assumed jerky load, the equivalent dynamic load results:
The nominal rating life is calculated from:
P = fz · (0,67 · F r + Y
2 · Fa ) = 1,2 · (0,67 · 30 + 2,9 · 19) = 90,2 kN
C p
466
L = L10 = — = —— = 238 · 10 6 10
revolutions
P
P
90,2
466 10/3
L 10 238 · 10 6
L h10 = —–— = –———— = 7945 hours
(60 · n) (60 · 500)
if
p 33 1 /3
10/3 33 1 /3
33
fN = —— — = —— = 0,4438
n 500
wird
fL C
= — · fN =
P
466
——— · 0,4438 = 2,3
90,2
The estimation should be carried out after evaluation of the specifications in the table Service life of bearings.
The bearing 23220EAS, at an operating temperature of t = 70 °C should be supplied with lubricating oil of the
viscosity class ISO VG 100. The kinematic viscosity in the operating state should be read out from the diagram
Operating viscosity. The plotted continuous line shows:
ν ≈ 27 mm²/s
The bearing 23220EAS has the average diameter
(D+d)
D pw = ––—— = 140 mm
2
so that from the diagram Reference viscosity ν 1 = 22 mm²/s can be taken from the diagram.