Loads


Minimum load

For additional
information
(→ Requisite minimum load)
Catalogue image - Fam - minimum load

Catalogue image - Flub for v n gt or eq 2000

Catalogue image - Flub for v n lt 2000

Perform calculations

The weight of the components supported by the bearing, together with external forces, generally exceed the requisite minimum load. If this is not the case, the bearing must be subjected to an additional axial load.

However, the requisite minimum load can be neglected for bearings operating at relatively slow speeds, depending on the outside diameter (diagram 1).

Example:
A 29444 E bearing is to operate at 90 r/min, from diagram 1 with D = 420 mm the two lines converge below the blue line. Therefore, the minimum load requirement can be ignored.
Equivalent dynamic bearing load

For additional
information
(→ Equivalent dynamic bearing load)
Fr ≤ 0,55 Fa and:
  • if run-out in the bearing arrangement does not affect the load distribution in the spherical roller thrust bearing
    → P = 0,88 (Fa + X Fr)
  • if run-out in the bearing arrangement affects the load distribution in the spherical roller thrust bearing (e.g. the run-out of another bearing that induces radial forces)
    → P = Fa + X Fr

Fr > 0,55 Fa → Contact the SKF application engineering service. 
 
Perform calculations

Equivalent static bearing load

For additional
information
(→ Equivalent static bearing load)
Fr ≤ 0,55 Fa → P0 = Fa + X0 Fr

Fr > 0,55 Fa → Contact the SKF application engineering service.
 


Symbols

A
minimum load factor (→ product table)
Cr
load factor
= 1,8 for 292 series
= 2,0 for 293 series
= 2,2 for 294 series

bearing outside diameter [mm]
d
bearing bore diameter [mm]
f0factor for lubrication method.

For oil bath lubrication with a horizontal shaft and for grease lubrication:
= 3 for 292 series
= 3,5 for 293 series
= 4 for 294 series

For oil bath lubrication with a vertical shaft and for oil jet lubrication:
= 6 for 292 series
= 7 for 293 series
= 8 for 294 series
Fam
minimum axial load [kN]
Flub axial load required to overcome lubricant drag [kN]
Fr
radial load [kN]
n
rotational speed [r/min]

equivalent dynamic bearing load [kN]
P0 
equivalent static bearing load [kN]
X
calculation factor
= 1,1 for 292 series
= 1,2 for 293 series
= 1,3 for 294 series
X0
calculation factor
= 2,5 for 292 series
= 2,7 for 293 series
= 2,9 for 294 series
ν
actual operating viscosity of the lubricant [mm2/s]  
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