Page 145 - Gear Technology Solutions

Figure 5: Ratio = 2.9, Ease-Off (left) and Tooth contact (right) for
X1 = 0.15 and X2 = 0.0

Test calculations showed that the parallel profile shift is limited to small profile shift
coefficients. Figure 5 shows the analysis results of a parallel profile shift of X1 =
0.15 and X2 = 0.0 (compared to the baseline without profile shift in Figure 2). The
tooth contact looks similar to the contact of the baseline in Figure 2, but the active
working profile is larger than the baseline contact. The lost top area is only about
50% of the baseline and the lost root area is about the same size as the lost root
area of the baseline. In summary, the parallel pinion profile shift achieved a
noticeable improvement by increasing the active working profile.

Large profile shift coefficients may reverse the positive effect of increasing the
active working profile, which is attributed to the fact that pinion and gear pitch line
separated after the parallel shift and do not pass through the new crossing point
between the pinion and the gear axes as shown in Figure 6. The reason is the
departure from the kinematic coupling condition between pinion and gear which
requires the pitch lines to meet at the crossing point of their axes.

Figure 6: Pinion and gear position after parallel profile shift

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