The synthesis of tooth profile shapes and helical gears of high hydraulic performance for rotary type pumps

Abstract

In this work a method is presented for the synthesis of high hydraulic performance of non involute helical gears and tooth profiles. Two gear capacity criteria are used in the synthesis: (1) the capacity based on optimal helical advance equal to the circular pitch for which perturbations of delivery speed and torque can be completely eliminated and (2) the capacity based on optimal tooth profile which consists substantially in circular arcs whose centers fall on the pitch point, and whose connecting part consists of a suitable curve which satisfies the condition for continuous contact without intersection of two mating teeth surfaces. The present paper deals with the theoretical basis and the comparison with test results. The tooth profile recommended as a result of this study has permitted size and cost reduction in a currently manufactured line of pumps with delivery pressure to 20 kg/cm 2.