Page 122 - Gear Technology Solutions

Figure 8: Cutter adjusted to the root line and generating gear plane
adjusted to the pitch line

The setup shown in Figure 8 realizes the correct kinematic coupling conditions
required for conjugacy between pinion and gear members. If pinion and gear
are generated on the pitch line (rather than on the root line), only then can
pinion and gear roll together on their respective pitch line without sliding. Only
the kinematic relationships of Figure 4 will achieve conjugate condition. This
also means that there are no deviations in the Ease-Off [4].

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Figure 9 shows the tooth contact analysis result of a Coniflex Pro gearset with
no profile and no length crowning which is the conjugate basis of each
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Coniflex Pro gearset. The Ease-Off surface to the left has zero deviations. This
results in full tooth contact within the entire working area of the flanks (Tooth
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Contact graphic in Figure 9). Also typical for a Coniflex Pro design is the
reduced stripe along the topland, outside of the working area. This “lost” area is
greatly reduced compared to past straight bevel gear designs. The motion
transmission graph in Figure 9 shows only some numerical variation and is
practically zero within the active working area of the meshing flanks.

Conjugate gears are not well suited for practical applications and require certain
amounts of profile and length crowning. The path of contact in straight bevel gears
is perpendicular to the pitch line which means that length crowning, being a
circular function, relieving toe and heel will not create a motion error because the
profile is still conjugate. Profile crowning in contrast has a direct influence on the
amplitude of the motion error. The development and optimization example in the

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