Based on their manufacturing principles, the manufacturing technology of face gear can be generally divided into three categories: Based on the “accurate simulation” of the meshing between small wheel and face gear, gear shaping, worm tool rolling, gear grinding, dished tool milling and gear grinding belong to this category; Based on the “approximate simulation” of the meshing between the small wheel and the face gear, that is, making the tool approach the involute of the production wheel to form the machined face gear in the process of motion. The face gear machined by plane tool milling, grinding, planing and insert milling belongs to this category; Based on additive manufacturing methods such as 3D printing, stamping and powder metallurgy, the blank processing of face gear direct forming is carried out. With the deepening of research, the manufacturing principle and method of face gear have been gradually mastered by people. The development of the next stage will step to a new level. Considering the characteristics and application fields of face gear transmission, improving machining efficiency, reducing production cost and intelligent manufacturing, the main research trends in the future are as follows:
(1) precision machining and intelligent manufacturing. Because the future application of face gear will face the fields of high-speed, reassembly and precision transmission, the accurate simulation based on the meshing between small wheel and face gear, especially the gear grinding technology, has the inherent advantage that the manufacturing accuracy can be guaranteed, and is the key field of face gear manufacturing research in the future. With the introduction and implementation of the national 13th five year plan and intelligent manufacturing plan, the manufacturing method based on accurate simulation method will be more integrated and intelligent. For example: self parameter design – gear coordinate data – workpiece preparation – clamping and cutting – on-line on-machine detection – data feedback – tool dressing – full intelligent operation of any link of the machining chain until the spindle adjustment of the machine tool. Because the relative position, motion and detection results of cutting tools, dressing wheels, machine tool spindles and workpieces have a vital impact on the final accuracy and surface quality of workpieces, it is necessary to describe the parameters in these links and reveal the coupling law of these parameters on manufacturing accuracy.
(2) manufacturing technology for surface integrity and fatigue resistance. From the above several processing methods, it can be seen that the processing of gears in front mainly focuses on the exploration of the principle and feasibility of various processing methods, and has not gone deep into the research on the influence mechanism of processing quality on gear transmission performance. However, surface defects are easy to appear in the heat treatment, especially in the machining of the final process, and the surface integrity of the gear determines its service performance to a great extent. Surface integrity refers to the surface state without damage or strengthening, which mainly involves performance indexes such as fatigue, friction and wear. Due to the limitation of undercutting and sharpening conditions, the bearing tooth width of face gear is limited. Therefore, for face gear for high-speed and heavy-duty applications, it is particularly important to improve its surface integrity to strengthen its anti fatigue ability. In the future, the development of face gear material selection, heat treatment and surface treatment technology should be strengthened, such as shot peening, rolling, grinding, polishing, laser shock strengthening and other surface treatment processes.
(3) coordinated development in the industry. From the research distribution of face gear transmission, the joint R & D force of foreign countries can not be ignored in promoting the development of face gear transmission technology to the final mature application. For example, in rds-21 and other programs, the U.S. military, NASA, Boeing, Canada North Star, the University of Illinois at Chicago and other institutions have participated in the design, manufacturing and testing of face gear transmission. As a new transmission mode, face gear transmission involves a wide range of problems. It is a system engineering related to the integration of materials, manufacturing, equipment, detection, control, performance, dynamics and other technologies. Therefore, in the R & D of face gear transmission and its manufacturing technology, several joint R & D teams will be formed in the future to overcome the technical problems of high-quality manufacturing of face gear.
(4) sustainability and green manufacturing. There are comprehensive literature on the green and sustainable development of gear manufacturing technology at home and abroad. Domestic environmental pollution is becoming more and more serious. In order to develop environment-friendly gear manufacturing technology, we have to introduce foreign advanced technology, digest, absorb and develop. Therefore, the sustainability and green manufacturing of face gear are also the clear trend of future development. For face gear, from the perspective of sustainability and green manufacturing, we should focus on the development of manufacturing methods based on “approximate simulation” to improve the applicability and universality of tools, and realize the standardization and serialization of tools. In terms of reducing material application, focus on the development of blank methods for rapid prototyping, such as 3D printing, stamping, forging, powder metallurgy, precision casting and other preparation methods.
(5) development of new manufacturing technology. With the development of intelligent technology and the independent drive and control technology of each axis of multi axis machine tool, the “approximate simulation” manufacturing method of face gear will gradually replace the “accurate simulation” manufacturing method. There are three reasons: first, it is more practical to obtain ideal meshing performance than simply pursuing manufacturing accuracy. For example, in order to reduce vibration and noise and improve fatigue life, it is often necessary to shape the standard and theoretical tooth surfaces. Although “approximate simulation” can not obtain accurate tooth surfaces, it can obtain good meshing performance through the adjustment of manufacturing parameters. Second, if high machining efficiency is not required, the point contact method can be used in “approximate simulation” machining to obtain accurate tooth surface, and its manufacturing accuracy depends on the control accuracy of each axis of the machine tool. Third, because the tool has abandoned the rigid limit of solid surface, it will form the production wheel surface completely based on motion, and the development of manufacturing technology based on “approximate simulation” will be more flexible. For example, research on continuous grinding method of face gear based on straight edge tool. Therefore, for face gear, there will be the development of new manufacturing technology based on “approximate simulation”. In addition, the manufacturing methods applied to other types of gear transmission will also be applied to the processing of face gear, that is, the development of new manufacturing technology of face gear based on technology migration, such as shaving, rolling, multi process compound processing, ion implantation, vibration finishing and other new manufacturing and surface treatment technologies.
In conclusion, face gear transmission has certain advantages and broad application prospects in the future. Foreign face gear manufacturing technology is becoming more and more mature, and China’s face gear transmission manufacturing technology has also made great progress. In the next stage, the development of China’s face gear manufacturing technology will make quantitative and qualitative improvement. Its research trends mainly focus on: precision machining, intelligent manufacturing, improvement of surface integrity and fatigue resistance, coordinated development in the industry, sustainability and green manufacturing, development of new manufacturing technology, etc.