Theoretical Analysis of the Strength of Internal Gear Drive With Zero-Tooth-Difference

In this paper we apply internal gear drive pair, with zero-tooth-difference, in the coupling mechanism to connect the output shaft of reducer and the rotor of pump in the submerged-motor-driven PC pumping system for oil production. Because there are dual modifications along radial and tangential direction for the cut of gear teeth, the gear-tooth thickness will be reduced and thus the strength of the teeth will be weakened evidently. At present, there is no theoretical criteria for the strength verification suitable for such mechanism design. The new calculating formulae for contacting stress of tooth surface and bending stress of tooth-root were established in this paper just for this reason, which not only provide the strength verifying criteria for gear-tooth but can also be regarded as the theoretical basis for the design of internal gear drive mechanism with zero-tooth-difference.