Modification Coefficient Selection Of The Involute Internal Gear With Zero-tooth-difference Mechanism And Machining Method

Thrust-offset gear coupling is a new type of coupling. It is designed especially for submersible progressive cavity pumping system. It has the advantages of larger axial and radial bearing capacity, higher transmission efficiency, less energy loss, and longer lifespan, etc. The internal gear mechanism with zero-tooth-difference is an important mechanism in the thrust-offset gear-coupling device, but its theoretical research work is not enough and further research and discussion are necessary.This paper analyzes the relationship between the maximum center distance and modification coefficient, gets the engaging equation in case of pinion and gear of involute internal gear with zero-tooth-difference mechanism being displaced, expounds the tooth profile engaging process of the internal gear couple with zero-tooth-difference, and calculates the starting and ending contact points . It is not reasonable to verify the strength of gear teeth with the traditional formula, and therefore the new checking equation is deduced that is valid for the gear with zero-tooth-difference mechanism.Based on the foregoing theory, this work presents a method to select modification coefficient of the involute internal gear with zero-tooth-difference mechanism. The procedures are to determine the domain of initial value firstly, then get the reasonable set of modification coefficient according to the tooth profile engaging equation and other constraint conditions. This method is simple, intuitive and exact. The parameters are serialized. In this thesis, the gear profile was drawn and the simulation of zero-tooth-difference mechanism's transformation was presented by UG, we can watch the coupling status intuitively.At last, the method of milling the internal gear is presented, which will reduce expenditure of machining, enhance the working accuracy, promote the surface roughness, cut the work hour and be suit for mass production. By virtual of simulation of working process, this method is proved to be feasible.