ABSTRACT
In parallel-axes gearing, a power from a driving shaft is transmitted to a driven shaft by means of two gears engaged in mesh with one another. The involute tooth flanks of a gear and a mating pinion in a parallel-axes gear pair interact with one another when a rotary motion is transmitted by means of a parallel-axes gear pair. Interaction between the tooth flanks of a gear and a mating pinion resembles that in a cam mechanism. In both cases, the working surfaces of a driving member push over the working surfaces of the driven member. The key difference between parallel-axes gearing and cam mechanisms is that in a gear pair, at certain instants of time, two or even more pairs of tooth flanks interact with one another simultaneously. Three different types of contact ratio are distinguished, that is: the transverse contact ratio, mp; the face contact ratio, mF; the total contact ratio, mt.
