Dynamic axial load carrying capacity

High-capacity cylindrical roller bearings with flanges on both the inner and outer rings can support axial loads in addition to radial loads. Fa must not exceed 0,5 Fr.
The axial load carrying capacity is primarily determined by the ability of the sliding surfaces of the roller end / flange contact to support loads. Factors having the greatest effect on this ability are the lubricant, operating temperature and the ability of the bearing to dissipate heat.
The formulae below are valid for normal operating conditions, i.e.:
  • ΔT ≈ 60 °C between the bearing operating and ambient temperature
  • specific heat loss ≈ 0,5 mW/mm2
  • viscosity ratio κ ≥ 2
  • misalignment ≤ 1 minute of arc
    For misalignment > 1 minute of arc, contact the SKF application engineering service.

Depending on the bearing size and the application conditions the permissible axial load is to be limited:

  • For constantly acting load to avoid any risk of flange damage
    Fap max ≤ 0,0035 D1,7
  • Surface of outside and bore diameter π B (D + d) ≤ 50 000 mm2

    Perform calculations

  • Surface of outside and bore diameter π B (D + d) > 50 000 mm2

    Perform calculations

  • Circulating oil applications

    Perform calculations

  • For brief periods, provided it does not increase the bearing operating temperature > 5 °C temporarily

    Fap brief ≤ 2 Fap

    where
    Fap = Fap, Fap oil or Fap max

    Depending on the bearing size, load and speed, this “brief period” covers only several seconds or can last a few minutes. As rule of thumb it can be assumed that a “brief period” is the time it takes for the bearing to make 1 000 revolutions.

  • Occasional shock loads

    Fap shock ≤ 0,0085 D1,7

Symbols

B=bearing width [mm]
C0
=basic static load rating [kN] (→ product table)
d
=
bearing bore diameter [mm]
D
=
bearing outside diameter [mm]
ΔTS
=
temperature difference between incoming and outgoing oil flow [°C]
Fa=axial load [kN]
Fap=
permissible axial load [kN]
Fap brief
=
maximal axial load for brief periods [kN]
Fap max=
maximal constantly acting axial load [kN]
Fap oil
=
maximum permissible axial load in circulating oil applications [kN]
Fap shock=
maximal occasional axial shock load [kN]
Fr=radial load [kN]
k1=lubrication factor
= 1,5 for oil lubrication
= 1 for grease lubrication
k2=lubrication factor
= 0,15 for oil lubrication
= 0,1 for grease lubrication
n=rotational speed [r/min]
VS
=
amount of oil flow [l/min]
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