ESDU 96011:2010

INTRODUCTION

ESDUpac A9611 provides a computer program for calculating the
key dimensions, motion characteristics, forces, torques and power
requirement for the operation of either external or internal Geneva
mechanisms. Both constant and varying crank angular velocity
definitions are permissible. Power is transmitted between the crank
and wheel by either roller bearings or pins. Crowned or cylindrical
profiles of these components are included. Two design strategies
are provided. The designer may specify the Geneva wheel dimensions
and the distance between crank and wheel shaft centres will then be
calculated. Alternatively, the centre distance is specified and
then the wheel diameter is evaluated.

The program determines the dependent dimensions, wheel motion,
contact and bearing forces plus the crank torque and power required
to drive the crank and produce the specified motion. Contact
stresses and the dimensions of the contact area on the slot face
and roller (or pin) are determined and compared with the specified
limits. When a bearing is selected, its strength and life are
calculated and compared with the published performance criteria.
Similarly, the characteristics of a lubricant film are evaluated
when oil lubrication is specified. If any of the applicable
performance limits are exceeded, the program will issue an
appropriate warning. If the crank angular velocity has been
specified as constant, the limiting speed will be determined and a
warning issued if this speed is exceeded.

In addition to a descriptive output file reproducing the input
specifications and listing the results of the analysis, the program
generates a series of data files in ASCII format. Separate files
are provided which define the wheel motion, mechanism forces,
contact stresses and deformations and lubrication data (when
applicable). A DXF output file provides a graphical representation
of the outline of the Geneva wheel, for the external Geneva
only.

The analytical techniques implemented in the program are those
described in ESDU 96002, entitled "Geneva mechanism. Part 1:
Design" (Reference 2) and ESDU ME3, entitled "Analysis of Geneva
mechanisms: derivation of kinematic and kinetostatic equations"
(Reference 1). The applicable assumptions are stated in these
documents and the program output must be considered in respect of
the theoretical limitations and practical considerations of the
design process.

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