Digital Design Of Zero-Tooth-Difference Methanism

The involute zero-tooth-difference internal gear mechanism has the advantages of structural simple, fewer parts, higher precision, stable drive esc. The axes of internal and external gears parallel, adopt bigger running clearance, the axes disalignment, can achieve transmission speed unchangeable ,but change the motion. The paper use the involute zero-tooth-difference internal gear mechanism in the trust-offset gear coupling, achieve the planet deflexion movement of output shaft relative to input shaft.The paper analyzes the tooth profile engaging process of the internal gear couple with zero-tooth-difference, and calculates the starting and ending contact points; indicates that is not reasonable to verify the strength of gear teeth with the traditional formula, and the other checking equation are deduced that is valid for it. Use the reliability design theory, probes into a method on the reliability design of zero-tooth-difference internal gear.The paper adopt digital design, base on UG NX software platform, use solid model, assembly, animation and numerically controlled machining, research the design and construction process of zero-tooth -difference internal gear mechanism. The paper study a method to complete the involute zero-tooth-difference internal gear mechanism through parametric design. We just need change the parameters to get a new gear, this make the period of the gear design shorten greatly and avoid the repeat work and improve efficiency. And the moment simulation of zero-tooth-difference mechanism's transformation was presented , we can watch the coupling status intuitively.Because of the bigger modification coefficient and a fewer teeth of the internal gear couple with zero-tooth-difference, by UG CAM, the internal gear is processed in the mill planar, which will reduce expenditure of machining, enhance the working accuracy, promote the surface roughness, cut the work hour and be suit for mass production.