Abstract:Started from practical engineering need, based on object reverse engineering (RE) technologies, referenced from the existing relevant research results, the solution of reverse route and method of basic parameters of the involute cylindrical helical gear are studied. The main idea was how to solve in reverse the base circle radius to determine whether or not tooth profile curve was an involute. On the premise of clear involute profile, according as scanning point cloud, with the help of three dimensional (3D) software about reverse and its digital measurement function, the gear transverse plane information and the whole depth, addendum circle, dedendum circle and common normal line such main geometry size were obtained. Then according to the gear meshing theory, measurement technology theory, the module, pressure angle, tooth coefficient helix angle and other parameters were solved gradually in reverse. Through a pair of helical cylindrical gear reversely derived from the engineering practice, the main parameter extraction methods and process were given so as to verify the feasibility of the method mentioned. In view of point cloud and reverse solution type of gear, geometric measurement method and operability, programming tool ease of use and other aspects, it is different from the main references 1 and 2 described of two kinds of the reverse solution method of parameters, but it possesses the advantages of them both.