Synthesis and CAD-Examination of a Cylindrical Gear Pair Derived from a Cosine Profiled Rack

Abstract

The problematic of gear profiles has again come to the fore during the power demands imposed by technical development. Most of nowadays gears have involute profile due to its numerous ad-vantages. The most important is that that axis distance variation does not affect the transmission ratio. According to [1], a cosine gear drive has a lower slip coefficient and the contact and bending stresses by charge are significantly lower compared to an involute gear. This paper presents a study regarding the generation synthesis of a cosine profiled gear pair, using a single cosine profiled rack, in a CAD environment. The profile of the generating rack and the mathematical computations of the equations of gearing were performed in a Mathcad environment. The tool models were created in Autodesk Inventor. Then it was implemented in Autodesk AutoCAD and using its special programming language (Auto lisp), a simultaneous subtraction-rolling method was used to obtain a realistic simulation of the meshing of the cut gear with the rack. Implementing the generated gears in Autodesk Inventor environment, tests were performed in order to compare the cosine profile of the generated gears with the profile of the involute gears. In the near future, we intend to exploit the results obtained and compare the transmission quality of the involute gears with the cosine gears.