Driven by the rapid development of automobile, wind power, high-speed railway, construction machinery and other industries, China’s gear industry has developed rapidly. In 2010, the production and sales scale of gear products has reached 146 billion yuan. China has become a real worldcountry But there is still a big gap from manufacturing power. At present, China’s gear products are undergoing a transformation from medium and low-end to high-end, and a few high-end products have reached the international advanced level. However, in general, China’s gear products can not meet the supporting requirements of key engineering equipment, and high-end products are still controlled by others. High end products such as automobile automatic transmission, high-speed rail drive unit and gear transmission device of large energy equipment rely heavily on imports, and the import and export deficit is still increasing year by year. In 2010, the gear import was US $10.4 billion, with a deficit of US $8 billion. Compared with the advanced industrialized countries in the world, the following problems mainly exist in the design and manufacturing of gear products in China.
(1) Lack of basic research and basic data: lack of basic experimental research related to fatigue limit stress and metallographic structure map of gear materials, and lack of basic research such as new tooth shape research, load spectrum test and processing technology research, resulting in lack of data support for product design and manufacturing. In addition, professional software development and application lag behind, and multidisciplinary comprehensive design technology and means lag behind.
(2) Low quality of gear materials: there is a large gap between gear materials and advanced countries, mainly reflected in the low purity and uniformity of steel, high oxygen content and non-metallic inclusions; The hardenability of steel fluctuates greatly and the hardenability bandwidth; High temperature and high performance steel, low temperature impact steel, rapid nitriding steel, economical large and medium modulus steel and high-performance engineering plastics are lacking.
(3) The level of gear heat treatment process is not high: carburizing and quenching deformation is large; Root cracking is easy to occur in induction quenching; Nitriding has the problems of low efficiency and shallow layer depth. Although rare earth catalytic nitriding has achieved good results, it still has great limitations; Lack of effective process control methods.
(4) The gap between high-grade process equipment is obvious: there is a big gap between cemented carbide tools and foreign countries, and almost all high-efficiency hobbing tools, dry cutting tools, high-grade CBN tools and high-grade grinding wheels for gear grinding are imported; High efficiency gear making machine tools and high-grade CNC forming gear grinding machines still basically rely on imports; Large and small gear measuring instruments and in-situ rapid measuring machines are still blank; Large modulusprocessing equipment and other core equipment are completely blocked by foreign technology Still controlled by others.
(5) Low production efficiency and poor quality stability of gear products: Although China has imported many high-grade gear manufacturing equipment, due to the gap in the use of cutting tools and equipment, the selection of manufacturing process parameters and production management, the product quality stability is poor, the production efficiency is low and the energy consumption is high.
(6) The testing and evaluation service capacity needs to be improved urgently: the testing service capacity of the national gear product quality supervision and inspection center is insufficient, many new products in the gear industry have not been tested, verified and evaluated by a third party, and the industry cannot accumulate design data, which directly affects the improvement of the overall design level and innovation ability of the gear industry.
(7) Standardization needs to be strengthened urgently: due to low standardization investment and other reasons, China’s gear industry has few applicable standards and low standard implementation rate, which can not meet the needs of industrial development. Most gear standards in China are transformed from foreign standards, the basic data are lack of verification, and some key data do not adapt to the domestic technical level.