Page 105 - Rollingbearings

Size selection based on rating life
Table 5
Viscosity classiication to ISO 3448

Viscosity grade Kinematic viscosity limits
at 40 °C (105°F)
mean min. max.
– mm 2 /s

ISO VG 2 2,2 1,98 2,42
ISO VG 3 3,2 2,88 3,52
ISO VG 5 4,6 4,14 5,06
ISO VG 7 6,8 6,12 7,48
ISO VG 10 10 9,00 11,0
ISO VG 15 15 13,5 16,5
ISO VG 22 22 19,8 24,2
ISO VG 32 32 28,8 35,2
ISO VG 46 46 41,4 50,6

ISO VG 68 68 61,2 74,8
ISO VG 100 100 90,0 110
ISO VG 150 150 135 165
ISO VG 220 220 198 242
ISO VG 320 320 288 352
ISO VG 460 460 414 506
ISO VG 680 680 612 748
ISO VG 1 000 1 000 900 1 100
ISO VG 1 500 1 500 1 350 1 650

Diagram 15
Bearing size
Lubrication condition
Boundary lubrication Mixed lubrication Full ilm lubrication

B.3

EP beneicial
0,1 1,0 4,0 κ
Lubrication
condition
100 0
Load carried by asperities [%]
Load carried by lubricant ilm [%]
0 100

Lubrication condition κ Size selection

Boundary lubrication
Full asperity contact, wear without EP/AW additives, high friction κ ≤ 0,1 static safety factor
Mixed lubrication
Reducing asperity contact, wear and surface fatigue without EP/AW 0,1 < κ ≤ 4 SKF rating life and static safety factor 1)
additives, friction reduced
Full ilm lubrication
No asperity contact, increasing viscous frictional moment κ > 4 SKF rating life (no life gain, possible higher temperatures)
and static safety factor 1)

1) This applies to peak load.

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