**China Rolling Mill Oil Film Bearing Technology (3)** Home > Bearing Knowledge > China Rolling Mill Oil Film Bearing Skills (3) *Created on 2018/5/16* var cpro_id = "u3440131";

China Rolling Mill Oil Film Bearing Skills (3)

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/*250*250 was created on 2017/12/25*/ var cpro_id = 'u3171089';

At that time, the main focus was on understanding the operational mechanism of oil film bearings. Researchers began to develop mathematical models based on classical smooth theory, using numerical methods and quasi-analytical approaches to deepen theoretical research. The classical theory suggested that the peak pressure in the oil film could reach over 100 MPa. However, some experts focused only on high-elastic flow in reverse-shaped contacts, considering sliding bearings as atypical problems, and even believing that heavy-duty oil film bearings were not within the scope of elastic flow theory. After further research, it was discovered that the circumferential distribution of film thickness showed a distinct "necking" phenomenon unique to the theory of elastic flow. The axial distribution also differed from classical theories, with the pressure peak shifting backward. Additionally, the eccentricity could be calculated to exceed ε > 1, proving that rolling mill oil film bearings fall under the category of elastohydrodynamic problems. As modern continuous rolling mills moved toward higher speeds and heavier loads, thermal elasto-mechanics theory was introduced. With the deepening of both static and dynamic pressure lubrication research, the development of China’s first static-dynamic oil film bearing was depicted. In terms of product development, the roots of China's rolling mill oil film bearings can be traced back to Soviet-era bearings produced in the early 1950s and small-scale factory-made components. At that time, these bearings were only suitable for low-speed rolling. Their layout was inconvenient for assembly, disassembly, and maintenance. Starting in the mid-1960s, China developed its own thick plate, extra-thick plate mill, and 1700mm hot and cold tandem mill. Due to the difficulty of producing large rolling bearings, oil film bearings became the preferred choice. The first generation of domestic rolling mill oil film bearings, such as the φ1300mm bearing used in the 4200mm thick plate mill, was designed for low speed and heavy load. It improved upon Soviet designs. The second generation, represented by the φ1100mm bearing in the 1700mm hot and cold continuous mill, saw improvements in speed and layout. The third generation, such as the φ500mm static-dynamic oil film bearing in the 650mm plate rolling mill, significantly enhanced performance, doubling the load capacity and approaching the level of Mogoil bearings. This marked China’s third independent development of static-dynamic oil film bearings after the U.S. and the former Soviet Union. China’s ability to independently develop rolling mill oil film bearings ranks second only to the U.S. and the former Soviet Union. However, in terms of static pressure film bearing research and method selection, China has made notable progress. For example, while the U.S. chose one central oil chamber and the former Soviet Union opted for four chambers, China selected an axially symmetric double-oil chamber design. By 1994, oil film bearings had evolved from single to double chambers, as seen in the φ1350mm TZ oil film bearing developed for Jiuquan Iron and Steel Company. This design featured symmetrical double-oil chambers, hydraulic locking, new reverse sealing, bidirectional thrust, and rapid assembly/disassembly techniques. There are three types of oil film bearings used in China’s rolling mills: pure static pressure, pure dynamic pressure, and static-dynamic hybrid. Pure static pressure bearings have not been widely adopted in rolling applications, while pure dynamic ones are commonly used in reversing and hot strip mills. Static-dynamic bearings are mainly used in cold tandem mills and for intensified rolling in reversible mills. The complete set of these bearings includes: 1. **Bearing Body Design and Fabrication**: Determining the shape, size, orientation, and primary parameters of the oil cavity. Ensuring high load capacity and precision through numerical calculations and production methods. Providing users with AGC system curves for oil film thickness correction. 2. **Ultra-High Pressure Oil Supply System**: Designed according to the specific needs of each mill. Ensuring safe, reliable operation with economic pressure-flow parameters. Including special equipment to balance pressure across multiple oil chambers. 3. **Hydraulic Locking and Rapid Assembly/Disassembly**: Developed in the late 1970s and applied in the 1980s. Used in continuous mills to control axial compression force and ensure safe and efficient installation. 4. **Reverse Sealing**: Modern mills require more advanced sealing solutions due to increased speeds. China has refined its sealing methods, covering mold design, rubber compounding, vulcanization, testing, and inspection. From the above aspects, it is clear that China has the capability to produce dynamic, static-dynamic oil film bearings and their associated oil supply systems, meeting the needs of modern rolling mills. This represents a well-established engineering system, developed through close collaboration between Chinese engineers and operators, integrating foreign technologies to reach a higher level. --- **Related Bearing Knowledge** The cooperation of rolling bearings – the effect and demand influence the life of data elements in paired bearing devices. Bearing selection should focus on analyzing the damage types of sliding bearings. --- This article links to http:// Please indicate the bearing network http:// Previous: The method of judging "Can INA bearing be available" is discussed in detail in the next section: How to properly use NTN bearing

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