PDF A study on prediction validation of meshing gear pair backlash under ...
automation etc. is the backlash. No backlash exists until a gear is meshed with another gear in an assembly. In general, backlash is the lost motion between mating gear teeth (Fig. 2). It may be measured along the line of action or on the pitch cylinder of the gears (transverse backlash) and, in the case of helical gears, normal to the teeth.