Wind turbine bearings are considered by the industry as one of the two parts that are difficult to localize, the other being the wind power control system. In recent years, China\'s wind power bearing industry has gradually formed large-scale and series production, with the industry scale continuously expanding and key technologies constantly breaking through. A number of reliability tests of technologies and products with independent intellectual property rights have been completed.

■■ High end bearings have become

Weakness in wind power equipment manufacturing

Despite the rapid development of China\'s equipment manufacturing industry, most of the high-end bearings used to support major equipment rely on imports. In addition, high-end bearings for energy equipment such as large wind turbine bearings, deep well drilling rig turntable bearings, and offshore drilling platform series bearings are also weak points for domestic enterprises.

Industry experts believe that as one of the important supporting equipment for wind turbines, wind turbine bearings have complex stress and vibration conditions, must withstand huge impact loads, and have high installation costs for yaw and pitch bearings. At the same time, they also need to achieve a lifespan of at least 20 years like the main engine. Due to the harsh working conditions and high reliability requirements of wind power equipment, wind power bearings have high technical complexity and are recognized as one of the two major parts (bearings and control systems) that are difficult to localize.

For a long period of time, domestic wind power bearings relied on foreign imports, which were expensive and increased the cost per kilowatt of wind power equipment, but also constrained the decline of wind power costs. According to experts, the technical threshold for yaw bearings and pitch bearings in wind power is relatively low, while the technical content of main shaft bearings and gearbox bearings is relatively high. Generator bearings are basically universal products with mature technology. At present, the production capacity of domestic wind power bearing enterprises is mainly concentrated in yaw bearings and variable pitch bearings, and mainly in supporting bearings for wind power equipment below 3 megawatts. For main shaft bearings and speed reducer bearings, they mainly rely on imports, with only a few domestic enterprises initially entering the field.

■■ Low speed wind power field

New requirements for wind turbines

Whether a wind turbine is good or not, bearings are the core factor. In traditional wind turbines, bearings play the role of the \"key master\". Due to the installation of wind turbines at high altitudes, maintenance costs are high, and the working environment is harsh, making them susceptible to pollution such as dust, water mist, and freezing. This requires the supporting bearings to have high rigidity and reliability to meet their 20-year service life requirements.

The testing of bearings is more stringent in the low-speed wind power field. In recent years, China has vigorously developed the clean onshore wind power industry and transferred it to power load centers such as the central and southeastern regions. However, due to the low average wind speed and fast changes in wind speed and direction in the local area, new requirements have been put forward for wind turbines.

The central and southern regions of China are typical low wind speed areas, located in the power load center with good grid access conditions. However, the average wind speed is low, the wind speed and direction change quickly, and it has the characteristics of low energy density and high turbulence intensity. This requires wind turbines to have the ability to capture energy, especially to withstand random alternating aerodynamic impacts. Targeted research and development of low-speed wind turbines and their supporting bearings are needed, and there is no precedent internationally, making independent innovation extremely difficult.

■■ Independent innovation helps

National Green and Low Carbon Development

Despite numerous difficulties, domestic bearing enterprises have not been hindered from exploring and moving forward. As the first domestic enterprise to carry out research and development of wind power supporting bearings, Luoyang LYC Bearing Co., Ltd. (hereinafter referred to as \"Luoyang\") has undergone more than 60 years of construction and development, and has become one of the comprehensive bearing manufacturing enterprises with a large production scale and strong supporting service capabilities in the Chinese bearing industry. It still maintains multiple records in the Chinese bearing industry, such as high precision level of bearing production, complex structure, and large external dimensions.

According to Zhang Wenbin, the head of the marketing department of Luozhou Company, Luozhou successfully developed the first domestically produced wind turbine yaw bearing in January 1997. Currently, it has been operating worry free in wind farms for more than 20 years and has become a qualified enterprise in the Chinese bearing industry in this field. In 2007, Luo Zhu presided over the drafting of the national machinery industry standard JB/T10705-2007 \"Rolling Bearings for Wind Turbine Bearings\". In 2012, he also presided over the drafting of the national standards for wind turbine bearings GB/T29717-2013 \"Rolling Bearings for Wind Turbine Yaw and Pitch Bearings\" and GB/T29718-2013 \"Rolling Bearings for Wind Turbine Main Shaft Bearings\".

In addition, Luoyang LYC Bearing Co., Ltd., as one of the main participating units, won the \"2018 National Science and Technology Progress Second Prize\" for its project \"Key Technology Research and Development and Large scale Engineering Application of Efficient Low Wind Speed Wind Turbine Units\", which is one of the few projects in the domestic bearing industry that has not received this national award.

Lu Bingheng, an academician of the CAE Member, believes that the research and development of high-end bearings involves a series of technical problems such as materials, grease and lubrication, manufacturing, design, bearing manufacturing equipment, inspection and test, as well as basic research and cross disciplines such as contact mechanics, lubrication theory, tribology, fatigue and damage, heat treatment and material organization. We must make key arrangements in industrial development policies, technological development plans, and other aspects to solve the problem of lagging development of high-end bearings in the equipment manufacturing industry.