Research On Pre-control Method Of Meshing Behavior And Key Technologies For Grinding Face Gear By Dish Wheel

Face-gear drive is a new developing type of transmission form. Compared with general spiral bevel gears, the face-gear drive has many advantages such as compact structure, high gear ratio, big contact ratio, alignment convenience. Particularly, the advantages of application of face gears are the possibility of split and the convergence of the torque, it has become focus of related research body in Europe and the United States in recent years, Typical representation is that an advanced split transmission equipment has been successful designed by America DARPA in TRP program using the face gear, reduced the quality of gear box by50%, enhance its power transmission density by35%.The meshing behavior is an important item to evaluate the transmission quality of face gear, and the3D topology shape of the tooth surface is the key factor to meshing behavior, such improvement of the meshing behavior is the research target of relevant scholars by means of tooth surface modification.At present, the face gear drive has been applied in main transmission system of rotorcraft in overseas, but processing technology of face gear is still in the initial stage in our country because of the blockade and security of technologies, especially the harden Gear Grinding technology is in theoretical analysis and experimental stage.This paper presented investigations such as gear blank design, tooth surface modification and meshing behavior pre-control, as well as the grinding technology by using grinding disk. The main results include:(1) Tooth geometry design of face gear is studied. Generating model of face gear was built and the tooth surface equation is derived based on differential geometry, gear meshing principle and shaping processing of face gear. The conditions of undercutting and pointing for an offset face-gear in the generation process were studied, the expressions of approximate and exact solution for inner radius and outer radius to avoid undercutting and pointing are provided, respectively. According to the study above, Parametric design program of face gear is compiled.(2)3D topology modification theory of face gear drive are studied and the pre-control method for meshing behavior is proposed. According to the principle of grinding, the tooth surface equation of modification parabolic has been obtained. Based on the principle of TCA, the position and orientation of the contact path of tooth face can be pre-control by changing modification parabola coefficient of tooth profile and tooth direction, reaching the purpose of reducing the sensitivity of the gear drive to the misalignments. At same time, the predesigned parabolic function of transmission errors can be obtained, which reducing noise and vibrations of the face-gear drive efficiently.(3) According to the generation theory and grinding disk motion of face gear ground by grinding disk, there grinding schemes are proposed and the model of the machine tool are set up. Based on the processing Principle of5-axis machining center, the gerneral equation of interpolated point coordinates is derivated, and NC manufacturing simulation is realized. Diamond roller motion trajectory for dressing grinding disk is calculation, which is consistent with the equidistant curve of grinding disk axis section profile. The pinion forming-grinding method is studied and the processing scheme of pinion double crowned modification is proposed, grinding wheel dressing program and cutter grinding program are completed.(4) The single indexing grinding of face gear is discussed. Contributing factors of gear machining errors are analyzed. Mathematical model for grinding face gear is built and the tooth surface equation is derived based on application of grinding disk, the theoretical tooth surface and real tooth surface are obtained. The relationship between grinding disk installation errors and tooth surface errors is researched. The analytical results are helpful to compensation of the tooth surface errors.(5) A face gear is ground by grinding disk and meshing experiments are finished. Grinding experiment of face gear has been completed on5-axis cnc grinding machine using grinding wheel dressing program and grinding program. The distribution situation of tooth face error is obtained based on using CNC gear measuring center and the error sources of tooth surface are analyzed. Pinion double crowned modification experiment has been completed, meshing behavior pre-control has been realized through the optimization of modification coefficients. The experimental results show that the performance pre-control theory based on TCA and grinding disk theory of the face gear are correct.