Development of a method to determine geometrical parameters of cylindrical gears.

Cylindrical gears, spur and helical, are widely used to transmit power between two objects. They are very precise mechanical components and the design behind them is very complex. When dealing with gears, in general, the attention is focused on a smooth and silent transmission, to ensure that all the parts work nicely. However, gears may break, as they are subject to different types of wear. In the best case, technical drawings of the part are available and spare parts can be obtained. Often, unfortunately, drawings of parts are not available and the people in charge of repairing and/or reproducing a part need special tools and algorithms to enable them to do their job. This work focuses on the development of an algorithm, to be implemented on coordinate measuring machines, capable of returning as output a set of geometric data of an unknown worn spur gear. The algorithm was first developed in Matlab®. Several cylindrical gear geometries were simulated in this environment. Subsequently, different spur gears were scanned with a coordinate measuring machine in order to obtain the coordinates of the necessary points, which were used as starting data to be entered into the code in order to validate it. The code was then translated into a programming language so that it could be read by the machine.