Page 132 - Gear Technology Solutions

The two neighboring tooth pairs each transmit 10% of the input torque. The
sharing of the load changes as the pitch position changes. The split of 80% and
twice 10% is the worst-case condition which is considered by a finite element
calculation. The load sharing can also be expressed with the effective contact
ratio. In the current example, the forged gearset has an effective contact ratio of
1.1 which means that 1.1 tooth pairs transmit the input torque at all times.

Figure 19: Comparison of load sharing and effective contact ratio
(50% of nominal load was applied)

A vertical line (as shown in Figure 19) in the lower diagram intersects with the
red and blue graphs at the 20% mark and with the green graph at the 60%
mark. This means, the maximal torque the teeth have to transmit is 60% of the
input torque because of the higher contribution of the neighboring tooth pairs.
The effective contact ratio of the cut differential gearset in this example is 1.4
(an average of 1.4 tooth pairs always transmitting the input torque) [8].

117