LOAD APPLIED TO A SINGLE BEARING
Calculation necessary to identify the most suitable bearing for the application depending on the applied loads
| LOAD APPLIED TO A SINGLE BEARING
Q = Load applied L = Distance between the center of gravity of the applied load and the sliding axis of the bearings A = Distance between the center of gravity of the bearings |
STATIC SAFETY COEFFICIENT
Fs = Co/F Where: Co= Static load factor F = Load applied to the bearing
The static safety factor determines the degree of safety that the bearing user wants to adopt against deformation of the bearing itself. A satisfactory degree of safety to avoid any malfunction should be:
Fs ≥ 3
N.B.: In the two sections of this page we have only considered the static load because, in applications where the speed is relatively low (up to 0.5 m / sec) the sizing is purely static. If the application requires higher speeds, the values of the dynamic allowable loads should be taken into consideration.
CALCULATION OF RESISTANCE
The strength of this material is defined as follows:
P0 = 750 N/mm2
For this calculation, the formula derived from HERTZ’s theory is used, relating to the crushing and the specific pressure generated between two solid elastic bodies, by linear contact subjected to a load.
CALCULATION OF DURATION
Bearings’ life depends on the applied load and the number of rotations and is calculated as follows:
L = (C/P)P Lh=(16666/n)x(C/P)p
| L = 106 | Nominal life in millions of revolutions, which is reached or exceeded by 90% of a sufficiently representative number of identical bearings, before the first signs of material fatigue appear |
| Lh | Nominal duration in hours of operation, corresponding to definition L |
| C | Dynamic load factor. For radial bearings C corresponds to a load of constant magnitude and direction after which a sufficiently representative number of identical bearings reaches a nominal life of one million revolutions |
| P | Equivalent bearing load |
| p = 10/3 | Duration exponent for cylindrical roller and needle roller bearings |