12.1 Basic principles

The load capacities are based on DIN ISO standard 14728 for roller-contact bearings.

In accordance with DIN, in most applications a permanent overall deformation of 0.0001 times the rolling element diameter can be permitted without adversely affecting the operating behavior of the bearing. This is referred to as the static capacity, C₀. When designing a new application, we recommend the equivalent static load be in line with the dynamic load capacity (C) to avoid plastic deformation.

The dynamic loading capacity C is the load at which a nominal service life L of 100,000 meters of travel is achieved. It is important to note when calculating the service life that not only the load, which acts vertically on the guideway, should be taken into account but the load range of all acting forces and moments.

The service life corresponds to the travel distance in meters, which is travelled from a guideway. This is before the first sign of material fatigue occurs within the roller guideway elements. The nominal service life is achieved when 90 % of the guideways of identical construction reach or exceed the corresponding travel distances under normal operating conditions.

Critical for the dimensioning of the guideways are the loads occurring in the ratio with the dynamic loading capacity C.

Definition of service life

As previously mentioned, the dynamic loading capacity C₁₀₀ is based on a service life of 100,000 meters. Other manufacturers frequently indicate the loading capacity C₅₀ for a service life of 50,000 meters. The resulting load capacities from this are more than 20 % higher than specified in the DIN ISO standard.

Conversion examples