Abstract:

ESDU 96011 introduces a computer program, ESDUpac A9611, for analysing the performance of either external or internal Geneva mechanisms. Starting with either the centre distance between the crank and wheel 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). If desired, external data files of the variation of the external torque acting on the Geneva wheel can be input. Similarly, if the angular velocity of the crank is not constant during each rotation, an external crank motion data file can be imported. Examples are given that demonstrate the creation of these files using either a Fortran program or a spreadsheet. Guidance in the design of Geneva mechanisms is given in ESDU 96002. Examples of the use of the software in realistic design situations appear in ESDU 96035 and ESDU 99001. The derivation of the kinematic and kinetostatic equations used is presented in ESDU ME3.