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15 Splines which accept Misalignment

15.1 A typical Spline Problem

When applying a spline connection between two shafts there is always the
question, what happens if the shafts have a certain misalignment? A spline
geometry which is designed and manufactured according to the standards [1,
2, 3, 4] will, in case of a press fit, not accept any misalignment above several
angular seconds. In the case of a transitional fit the misalignment may be sev-
eral angular minutes, but larger shaft angle differences are not acceptable and
lead to load concentration on the ends of the spline connection [5]. These load
concentrations which are caused by the misalignment generate reaction forc-
es. Because the spline rotates and the reaction forces are fixed in space, fluc-
tuating loads to the spline teeth which move from one end of the spline to the
opposite end during each revolution (see Figure 1).

The question is whether there is a spline design which can compensate for
certain shaft misalignments even with higher speeds. In the following sections,
two different designs for misalignment compensation are discussed.

Figure 1: Spline shaft and mating internal spline

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