A roller bearing is an assembly that supports the rotation of a shaft. Its ferrule and the roller are precision machined. Anti-rust oil or antirust grease is injected between the raceway and the rolling body in order to protect the surface of the raceway and the rolling body from rust before the bearing leaves the factory. Therefore, bearing roller manufacturers suggest that roller bearings should be cleaned before installation. Bearings that are sealed with anti-rust oil can be cleaned directly by gasoline or kerosene; if heavy oil or anti-rust grease are used for anti-rust, light mineral oil should be used first. For example, the grease is melted by heated 10# oil or transformer oil and cooled, then we can clean it with gasoline or kerosene. Bearings with dust caps or sealing rings on both sides are lubricated before delivery, so there is no need to clean them during installation. Bearings coated with grease for both lubrication and rust prevention also do not need to be cleaned during installation. In the cleaning and installation process, it is necessary to prevent foreign matter from falling into the bearing, because tiny abrasive particles will cause wear between the rolling body and the raceway, which increase the noise and vibration.
There are two main ways to assemble and disassemble all types of rolling bearing. The first way is to press the interference ferrule into the shaft or into the bearing seat hole; the second way is to increase its inner diameter through heating the bearing or cooling the bearing to reduce its outer diameter to make the bearing easily installed in the shaft or pushed into the seat hole. When adopting the pressurization method, mechanical force or hydraulic pressure will act directly on the assembled and disassembled seat ring through a special device, and it is never allowed to transmit the assembly and disassembly force through the rolling elements. Otherwise, it will cause indentation on the surface of the raceway and the rolling body, as well as increase noise and vibration and cause damage. If a heating or cooling method is used for assembly and disassembly, the heating or cooling temperature should be strictly controlled. The strength of the bearing working surface is affected by the metallographic structure of the metal surface. High temperature will cause tempering effect and too low temperature will cause the embrittlement of the metal surface. In general, the heating temperature shall not exceed 100℃, and the lowest cooling temperature shall not lower than -50 ℃. In the meantime, the heating must be uniform.
The practice has proved that improper installation of roller bearings is one of the reasons for premature damage. It is a very difficult thing to install and remove the interference ferrule. Therefore, how to assemble and disassemble the bearing must be considered when designing the supporting. Special equipment should be designed for the assembly and disassembly of large bearings in heavy machinery. The corresponding oil line, pipeline and pump shall be designed for high-pressure oil disassembly.
