Design and finite element analysis for helical gears with pinion circular arc teeth and gear parabolic curve teeth

A novel point contact gear drive with pinion circular arc teeth and gear parabolic curve teeth is proposed based on the application of two mismatched rack cutters. The rack cutter for generating a pinion is of normal circular arc profile, and the rack cutter for generating a gear is of normal parabolic curve profile which is tangent to the circular arc of the pinion. The number of contact points can be one or two by changing the design parameter of the parabolic curve. Equations of tooth surfaces are derived based on coordinate transformation and gear geometry theory. Computer program is developed to solve the tooth surface equations and establish the solid models. To find out the advantages and disadvantages of the proposed gear drives, the gear stress distribution and the contact deformation are investigated by using the finite element analysis. Three examples of the proposed gears and circular-arc gears are present to demonstrate the influence of the profile design parameters and the contact positions on the stress distribution. The result shows that the proposed gear drives can reduce 23.8%-35.3% contact stress or 23.2%-29.5% von Mises contact stress.