Evaluation of pitch deviations with comprehensive representation suitable for engagement evaluation in different types of gears

Gear tooth flank deviations should be characterized to evaluate individual gear accuracy directly linked to gear performance during engagement. The comprehensive pitch deviation representation we propose is calculated using multiple tooth flank surface deviations as 0-order form deviations. In this representation, pitch error is expressed by angle unit, not by length unit, and calculated from measured conventional deviation (profiles and leads) without measuring pitch deviation. For spur and helical gears, pitch deviation is expressed by a single length unit and also by a single angle unit. On the other hand, for bevel gear flank, pitch deviation expressed by length unit consists of many different values even on a single flank. Using the angle unit expression, form deviation is described exactly by a single parameter. The comprehensive representation we propose overcomes the disadvantages of conventional pitch deviation evaluation, going right to the point of gear engagement evaluation.