Melnyk V. Forming of large-size cylindrical gears by special hob-cutters adjusted for part blank profile

Thesis is devoted to solving of an actual scientific-technical task: forming of large-size cylindrical gears by special hob-cutters adjusted for part blank profile. The main prerequisite for the forming of large-size cylindrical gears is analysis of existing forming methods of large-size cylindrical gears with the use of developed software-based mathematical models for specification and mathematical description of initial forming contours as well as forming of other links of working and manufacturing gearing. By means of software-based models an analysis of large-size cylindrical gears forming taking into account undercut, modification and interference avoidance was carried out. This analysis allowed it to ascertain possibility of cylindrical gears forming after their wear of up to 8 mm in cog width. Forming of large-size cylindrical gears adjusted for part blank contour after such wear is allowed due to the use of Novikov or involute gearing on account of initial contour shift of hob-cutter with modified profile. On the basis of the research results special assembled hob-cutters of 20 mm module were designed and manufactured and large-size cylindrical gears were formed. Experimental-manufacturing implementation of worn-out large-size cylindrical Novikov gears forming technology is carried out on the basis of the "Ukrkomplekt" company with further operation on Inguletsky ore mining and processing enterprise. Keywords: forming, large-size cylindrical gears, hob-cutters, initial contour, cog cutting.