1 Scope
This document describes a procedure for the calculation of the micropitting load capacity
of cylindrical gears with external teeth. It has been developed on the basis of testing
and observation of oil-lubricated gear transmissions with modules between 3 mm and
11 mm and pitch line velocities of 8 m/s to 60 m/s. However, the procedure is applicable
to any gear pair where suitable reference data are available, providing the criteria
specified below are satisfied.
The formulae specified are applicable for driving as well as for driven cylindrical
gears with tooth profiles in line with the basic rack specified in ISO 53. They are also applicable for teeth conjugate to other basic racks where the virtual
contact ratio (εαn) is less than 2,5. The results are in good agreement with other methods for normal
working pressure angles up to 25°, reference helix angles up to 25° and in cases where
pitch line velocity is higher than 2 m/s.
This document is not applicable for the assessment of types of gear tooth surface
damage other than micropitting.