Involute gear is an extremely important basic part in various equipment manufacturing industries. In the outline of the national medium and long term science and technology development plan issued by the State Council, it is clearly pointed out that through tackling key technological problems, we will focus on the research and development of key basic parts and other key technologies required for major equipment, and list “basic parts and general components” as the priority theme. In the plan for the adjustment and revitalization of equipment manufacturing industry issued by the State Council, it is pointed out that it is necessary to combine the development of complete machines with the improvement of basic supporting level, and focus on the development of precision bearings and high-precision involute gear transmission devices as one of the main tasks of industrial adjustment and revitalization.
Over the past 30 years of reform and opening up, China’s involute gear industry has made great progress with the rapid development of the national economy, with a complete range of products. It is widely used in more than 20 fields, such as aviation and shipping, weapons and equipment, automobile and motorcycle agricultural machinery, machine tools, engineering machinery, rail transit, cement construction, hoisting and transportation, mining metallurgy, electric energy, petrochemical industry, instruments and meters. An independent and complete industrial system has been formed. Especially in recent years, driven by the rapid development of automobile, wind power, high-speed railway and infrastructure, the involute gear industry has become a trend of rapid development. By the end of 2020, that is, the end of the 14th five year plan, China’s total demand for involute gears will exceed 140 billion yuan, more than double the 68.3 billion yuan in 2015. It is a real world involute gear manufacturing country.
The rise of automobile industry promotes the development of involute gear transmission technology. The rise of navigation, aviation and aerospace industries and the use of modern large complete sets of industrial equipment put forward higher requirements for the quality, strength and reliability of involute gear transmission, which makes it high efficiency, high precision, high bearing capacity, high power density, low noise The research and development of small volume and high-performance involute gear transmission has become an important scientific and technological problem in the development of relevant industrial fields in China, and it is also an important frontier in the research of transmission machinery in the field of mechanical engineering. For the involute gear element, its core index is high bending strength, high contact strength and high transmission efficiency, that is, the involute gear tooth surface has high contact strength and high bending strength to improve the bearing capacity and realize lightweight at the same time. The above indexes are the basis and important influencing factors for realizing low noise, long service life and high reliability of involute gear transmission. At present, the research and development of high-performance involute gear transmission has become a key scientific and technological problem in the development of relevant industrial fields in China, and it is also an important frontier in the research of transmission machinery in the field of mechanical engineering.
Generally, the factors affecting the transmission performance of involute gears include meshing tooth surface, lubrication state, surface roughness, material and heat treatment. Among them, the meshing tooth surface is the direct action surface of motion and dynamic transformation. Here, the tooth surface structure of involute gear has developed from the initial rectangular teeth and cycloid teeth to the most widely used involute straight teeth and involute helical teeth. All stages of involute gear evolution are accompanied by the innovation and development of meshing tooth surface. The development of involute gear transmission technology shows that the tooth profile of tooth surface is the key factor for the innovation and development of involute gear. The traditional gear profile design theory is mainly based on the principle of conjugate surface. According to this principle, a more systematic and comprehensive system has been established from the solution of conjugate tooth surface to the analysis of tooth surface properties. However, with the development of production and science and technology, the existing involute gear design and analysis theory is gradually difficult or difficult to economically meet the requirements of higher transmission performance. For example, although involute gears are widely used, there are still the following problems: involute gears slide except for nodes. When the number of teeth is small, there is still large sliding at the tooth top and root, so it is difficult to achieve pure rolling contact; Its teeth are convex convex tooth surface contact, and the contact strength is also limited. In addition, the science and technology of the times is also the support for the development of involute gears.
For a long time in the past, special machine tools were usually used to manufacture conjugate curved tooth surfaces to realize the generative movement from cutter or grinding wheel to involute gear. This was also the core factor for people to consider choosing conjugate surfaces. In recent years, numerical control technology has developed by leaps and bounds, and has been widely used rapidly. CNC machine tools have become the basic equipment of involute gear Enterprises above Designated Size in China. The universality of NC machining makes the machining of complex surfaces no longer an insurmountable obstacle, which provides a technical guarantee for the development of new involute gears with better transmission characteristics. Therefore, more and more researchers start with the research of geometry, break through the limitations of the traditional conjugate surface principle, and explore the tooth profile design theory of high-performance gear represented by technical indexes such as high bending strength, high contact strength, high transmission efficiency and low vibration and noise. The research on the meshing theory of conjugate curve bevel gear provides a new theoretical basis for high-performance involute gear transmission. The tooth profile with concave convex arc point contact can be obtained by using the conjugate curve meshing theory, that is, the convex arc tooth profile and concave arc tooth profile mesh at the theoretical contact point. This tooth profile increases the relative radius of curvature and improves the contact strength. At the same time, using the spatial conjugate curve, the tooth surface contact trajectory can be adjusted more flexibly, which provides a new theoretical basis for the design of high-performance involute gear pair.