Abstract:

ESDU 96002 presents the equations used in the program of ESDU 96011 (ESDUpac A9611) for calculating the important performance indicators used in the design of internal and external Geneva mechanisms. Guidance is given on the choice of the input parameters to the program including typical values of material and lubricant properties and roller bearing design factors. If required, variable crank speed and external torque through the cycle may be used. The form of the output is discussed and guidance is given on the use of the program in design, for example, suggesting that the sensitivity of the results to changes in values of particular input parameters be explored. The derivation of the equations appears in ESDU ME3 and the program is introduced in ESDU 96011. Starting with either the centre distance between the wheel and crank shafts or the diameter of the wheel, the program determines the key dimensions of the mechanism and makes a number of checks on the validity of the geometry. From the defined motion of the crank, the wheel motion, bearing forces, input torque, frame shaking force, contact stress between the roller (or pin) and the slot, lubricant film thickness (if applicable) and roller life (if applicable), are calculated. In order to communicate with other computer aided design software, a DXF file of the outline of the wheel is generated (for external Genevas only). Examples of the use of the software in realistic design situations appear in ESDU 96035.