| Spiral bevel gears are one of basic mechanical units to transmit motion between concurrent axes. Because the transmission has quite a few merits, such as the big overlap ratio, the high loading capacity, the high transmitting efficiency, the stability, the small noises, and so on, they are widely used in automotive vehicle, planes, machine tools and all kinds of machines. But the theoretical complexity causes that the machine tool structure and the machining adjustment are the most complex among all the stock-removing machines, and that the machining periodicity is very long. Therefore, it is of much importance to study machine tools of spiral bevel gears with high speed, high precision, high efficiency, much flexibility and high automation.Because of the complex technology of spiral bevel gears, there are only three companies who have the technology: American Gleason, Swiss Oerlikon and German Klingelnberg. They respectively stand for three kinds of spiral bevel gears, and have their own systems which are not open to one another. These countries have developed out CNC machine tools for spiral bevel gears for applying CNC technology.Researchers still put their emphasis on studying Gleason machine tools in our country. This kind of machine have mach parameters to be adjusted and is not easy to operated, and the parameters of this machine lie on the skilled workers' experience and technical levels, which baffles the application and development of spiral bevel gears machines.Although the basic theories about the bevel gear are known, there is a long distance in NC engineering applications in our country. The system of CNC is mainly imported from Fanuc Company and Siemens Company. But, this universal CNC system is unable to make full of its functions, and CAD and CAM are independent, what's more, the price is also very high. If we only rely on importation, the higher price of tools and the blocked technology are verydisadvantageous to the application of gear machines in our countries. So we should have our own NC systems of spiral bevel gears. In view of our successfully-developing experience for many years, we put forward the thought of developing the CNC system for spiral bevel gears. My dissertation has drawn from the project - the Study of Copying & Digitizing Machining Technology which is sponsored by Natural Science Foundation of Henan province(Item number: 004053100).Centered around this subject, this paper mainly studies the numerical control machining theories, and the main work is as follows:1. The engagement theory of spiral bevel gears is presented, including the tangent plane, normal vector, curvature of spatial curved surfaces and relative curvature of conjugate surfaces, et al., where relative curvature is emphasized.2. The structure of Gleason numerical control machining tools is analyzed,, and the mathematical models of the tools and the tooth flank are established. By meshing tooth flanks, this paper solves out the coordinates of tooth flanks, and simulates the tooth flanks.3. From the machining methods of spiral bevel gears, according to the parameters of nodal surface of generating gears and the relative position between the generating gear and the work piece, adjusts the parameters of machine tools, and develops the corresponding programs.4. Based on the analysis of the mathematical model of the tooth flank , according to the positional relations between tool pans and manufactured gears, deduces out the information about cutter location in the numerical control manufacture-the cutter center coordinates and the cutter shaft vector.5. According to the established mathematical model of machine tools, deduces out post processing formulas of CNC machine tools for spiral bevel gears.6. By combining the programming languages of VC++6.0 with Matlab, develops the software to simulate tooth faces and to adjust the parameters of machine tools, which makes full use of the merits of Matlab language such as the convenience, rapidness and accuracy in numerical calculation,... |
PDF Full Text Request