SKF - Rolling Bearings

Selecting bearing size using the life equations
Considering EP additives
EP additives in the lubricant can extend bearing
service life when, in accordance with
ISO 281, k < 1 and the factor for the contamination
level h c ≥ 0,2. Under these conditions,
a value of k = 1 can be applied in the calculation
of a SKF , if a proven lubricant with effective
EP additives is used. In this case, the life modification
factor has to be limited to a SKF ≤ 3, but
should never be lower than a SKF for normal
lubricants.
Viscosity-temperature diagram for ISO viscosity grades
(Mineral oils, viscosity index 95)
Viscosity [mm 2 /s]
1 000
For the remaining range, the life modification
factor a SKF can be determined using the
actual k of the application. In case of severe
contamination, i.e. contamination factor
h c < 0,2, the possible benefit of an EP additive
should be proven by testing. Refer to the information
about EP additives under Lubrication
(† page 239).
Diagram 6
B
500
200
ISO VG 1 500
100
1 000
680
50
460
320
220
150
100
68
46
20
22
32
15
10
10
5
20 30 40 50 60 70 80 90 100 110 120
(70) (85) (105) (120) (140) (160) (175) (195) (210) (230) (250)
Operating temperature [°C (°F)]
73