Page 203 - Gear Technology Solutions

categories and 4 sub-categories which are defined by national and internation-
al standards. An overview is given in Figure 2.

Studying the literature teaches that many large OEM’s pick the design pro-
posals, the tolerances and function features for one particular spline design
from several standards. In the process of answering the reader’s question it
will be proposed to use metric units for all calculations, apply the adden-
dum/dedendum recommendation by DIN and follow the ANSI guideline for side
fit and major diameter fit. In order to eliminate the confusion which, the design
by picking dimensions and tolerances from different standards might cause,
the following sections present a firm guideline for each step of the design, tol-
erancing and cutting tool definition.

Figure 2: Overview of different spline categories [1 through 7]

14.2 The Different Spline Functions and the Required Fits

If a splined shaft, for example the output of a transmission drives a rotor which
is mounted on its own bearings, then the function of the spline is not the cen-
tering of the rotor but merely torque transmission. In this case, a centering
function would just cause the transfer of misalignment and runout between
shaft and rotor, which leads to vibration and bearing wear. The described con-
nection should have backlash between the flanks and clearance between the
top of the internal and external teeth and their adjacent roots and use a profile
fit with backlash as shown in Figure 3.

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