PD ISO/TR 14521:2010

Foreword
Introduction
1 Scope
2 Normative references
3 Symbols and terminology
4 Formulae for calculation of dimensions
5 General
6 Geometrical data to be known for calculation
7 Forces, speeds and parameters for the calculation of
   stresses
8 Efficiency and power loss
9 Wear load capacity
10 Surface durability (pitting resistance)
11 Deflection
12 Tooth root strength
13 Temperature safety factor
14 Determination of the wheel bulk temperature
Annex A (informative) - Notes on physical parameters
Annex B (informative) - Methods for the determination of the
        parameters
Annex C (informative) - Lubricant film thickness according to
        EHL - theory
Annex D (informative) - Wear path definitions
Annex E (informative) - Notes on calculation wear
Annex F (informative) - Notes on tooth root strength
Annex G (informative) - The utilisation of existing tooling for
        machining of worm wheel teeth
Annex H (informative) - Adaptation of equations for the reference
        gear to own results of measurements
Annex I (informative) - Life time estimation for worm gears with
        a high risk of pitting damage
Annex J (informative) - Examples
Bibliography

Describes equations for calculating the load capacity of cylindrical worm gears and covers load ratings associated with wear, pitting, worm deflection, tooth breakage and temperature.