Cycloid Bevel Gears and hypoid gears adopt equal height teeth, which have the advantages of stable transmission, low noise and high bearing capacity. They are widely used in the main transmission of automobiles. At present, the machining of Cycloid Bevel Gears and hypoid gear pairs by using the spirac method can improve the efficiency of tooth alignment and be widely used. In order to explore a more efficient machining method, this paper studies the pre control method of the meshing characteristics of Cycloid Bevel Gear and hypoid gear pair, and puts forward a new tool inclined semi evolution machining method based on the plastic forming of gear wheel:
(1) The geometric parameter design of Cycloid Bevel Gear and hypoid gear blank is studied. According to the position and relative motion relationship among tools, machine tools and workpieces, the mathematical model of spirac method tooth cutting adjustment and tooth surface contact analysis is established, which provides a theoretical basis for the parameter optimization and further research of spirac method.
(2) A spirac gear cutting adjustment calculation method with preset contact area length coefficient is proposed. The instantaneous contact area length of the tooth surface is controlled by changing the cutter inclination angle, and the pre control of the bearing capacity of the gear pair is realized; A spirac gear cutting adjustment calculation method with preset contact trace directional angle is proposed, which completes the pre control of the directional angle of the butt contact trace, and realizes the symmetrical meshing characteristics of the contact trace of the working face and the non working face; On this basis, a comprehensive spirac gear cutting adjustment calculation method with preset length coefficient of contact area and directional angle of contact trace is obtained, which eliminates edge contact, reduces transmission noise, reduces transmission ratio error, improves motion stability and transmission accuracy, and realizes the forward and reverse transmission consistency of gear pair.
(3) Based on the spirac method tooth surface forming principle, taking the cycloid hypoid gear pair as an example, the tooth surface equations and tooth surface boundary calculation formulas of the large and gear pinion are derived, and the three-dimensional digital model of the gear pair is established.
(4) Based on the digital design of the gear pair, the sharpening, undercutting and shrinkage characteristics of the tooth top are analyzed and evaluated, as well as the interference of the gear pair. The correctness and enforceability of the spirac method for the pre control of the coupling characteristics are verified.
(5) Based on the spirac method tooth surface forming principle, taking the cycloid hypoid gear pair as an example, the simulation research and machining experiment research of digital tooth surface general NC machining are carried out, which is a single piece of Cycloid Bevel Gear and hypoid gear pair pinion batch production provides a general NC machine tool processing method that complies with the original drawing design parameters and obtains performance parameters based on spirac gear cutting principle.
(6) A new semi generative machining method of Cycloid Bevel Gear and hypoid gear pair formed by precision forging is proposed. The calculation method of gear pinion cutting adjustment and the mathematical model of large gear surface, as well as the three-dimensional digital model of gear pinion and large gear are established, The law of gear tooth surface modification is studied. Taking cycloid hypoid gear pair as an example, the feasibility of the new method is verified by tooth contact analysis and visual analysis. This method realizes the local efficiency manufacturing of Cycloid Bevel Gears and hypoid gears.
(7) Using 3D printing “melt deposition forming” technology, the machining experiment of the new semi evolution method is completed, and the correctness of the tooth profile of the gear wheel and pinion is verified according to the physical model.
(8) According to the gear tooth shape, the mold cavity model of the gear wheel is established, and the general machining simulation of the mold cavity of the gear wheel is completed based on the simulation research of the general NC machining of the digital tooth surface.