During the 11th Five Year Plan period, driven by the rapid development of automobile, wind power, high-speed rail, construction machinery and other industries, China’s gear industry has developed rapidly. In 2018, the scale of production and sales of gear products has reached 1960 billion yuan. China has become a real world gear manufacturing country, but there is still a big gap from a manufacturing power. At present, China’s gear products are undergoing the transformation from the low-end to the high-end, and a few high-end products have reached the international advanced level. But generally speaking, China’s gear products can not meet the matching requirements of key engineering equipment, high-end products are still controlled by people, auto automatic transmission, high-speed rail drive unit, large-scale energy equipment gear transmission and other high-end products rely heavily on imports, and the import and export deficit is still shrinking year by year. Compared with the advanced industrialized countries in the world, the following problems exist in the design and manufacture of gear products in China.
1.Lack of basic research and basic data
The lack of basic experimental research on the fatigue limit stress and metallographic structure map of gear materials, the lack of basic research on new tooth shape, load spectrum test and processing technology research, makes the product design and manufacturing lack of data support. In addition, the development and application of professional software are lagging behind, and the technology and means of multidisciplinary comprehensive design are lagging behind.
2.Low quality gear material
There is a big gap between gear materials and advanced countries, which is mainly reflected in the low purity and uniformity of steel, high oxygen content, non-metallic inclusions, etc.; large fluctuation in hardenability of steel, hardenability bandwidth; lack of high-temperature high-performance steel, low-temperature impact steel, rapid nitriding steel, economic large and medium modulus steel and high-performance engineering plastics.
3.Low level of gear heat treatment process
Carburizing and quenching have large deformation; induction quenching is easy to cause root cracking; there are problems of low efficiency and shallow layer in nitriding. Although rare earth catalysis has achieved good results, it still has great limitations; there is 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. Almost all of the high-efficiency hobbing tools, dry cutting tools, high-grade CBN tools and high-grade grinding wheels for gear grinding are imported; the high-efficiency gear making machine, high-grade CNC forming gear grinding machine and so on are still basically dependent on imports; large and small gear meters and in place fast measuring machines are still blank; core equipment such as large modulus bevel gear processing equipment is completely technically blocked abroad, Still under control.
5.Low production efficiency and poor quality stability of gear products
Although our country 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, production management and other aspects, the quality stability of products is poor, the production efficiency is low, and the energy consumption is high.
6.The ability of detection and evaluation service needs to be improved
The national gear product quality supervision and inspection center has insufficient testing service capacity. Many new products in the gear industry have not been tested, verified and evaluated by a third party. The industry cannot accumulate design data, which directly affects the overall design level and innovation ability of the gear industry.
7.Standardization needs to be strengthened
Due to the lack of 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 of the gear standards in China have been transformed from foreign standards. The basic data are lack of verification, and some key data are not suitable for the domestic technical level.