To illustrate the effect of waviness on calculated performance characteristics like transmission error and load distribution, we use a pinion gear mesh. Both gears are spur gears. As a reference calculation, only profile crowning is applied to the pinion. For a second calculation considering gear waviness, a waviness is applied on the pinion, having a reference amplitude. For a third calculation, the waviness amplitude is doubled. An LTCA for the three meshes is performed and the results are shown in Figure 12. We observe that the line load changes very little, far less than what would be needed to indicate the need for a change in design. It is interesting to note that the PPTE value does not change proportionally to the waviness amount. The most interesting result is that for the gears having waviness, the higher-order amplitudes in the spectrum of the transmission error increase. Here, we see the influence of the waviness on the transmission error.

Approximation of the measured waviness by superimposition of a few sinus-shaped forms with different amplitude, phase and wavelength. Right: Same form of waviness but increasing amplitude to study the effect of e.g., tool wear.

The above is not a systematic approach to the phenomenon of waviness and its influence on the performance of a gear mesh. Far more extensive parameter studies are required. However, it does illustrate that There is an influence of the waviness on performance characteristics. They are accessible through LTCA. Results are plausible and encouraging. The influence of waviness is negative (stresses and PPTE increase). The increase in PPTE indicates that the excitation of a gearbox housing by the gear mesh will be more in case waviness is present. This aspect is investigated in detail in the next section.