Page 204 - Gear Technology Solutions

Figure 3: Not centering connection

If a splined shaft is connected with the internal spline for example at the output
of a transmission and if the shaft is long in relation to its diameter, then a flank
centered fit as shown in Figure 4 is preferred. In order for correct flank center-
ing, the backlash between the internal spline teeth and the shaft spline teeth
has to be zero. To achieve such a transitional fit, the tolerances according to
ISO 7H (shaft spline) and 7n (internal spline) are recommended.

Figure 4: Flank centered connection

In case that a rotor like a sprocket is radially centered by the spline connection,
then major diameter transition fit (or interference fit) according to ISO (outside
shaft diameter tolerance H7 and major internal diameter tolerance n7 (or
H7/p7 for a press fit) can be used as shown in Figure 5. The profiles can be
made with backlash, or as transition or interference fit (see tolerance recom-
mendations in connection with Figure 3 and 4). The decision regarding the
flank fit depends on the operation schedule (one directional or two directional
torque transmission).

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