Rolling mill bearing FW value tolerance design and discuss

The design of the rolling mill bearing FW value tolerance introduction to 2019 - is determined 03 - 28 Qiao Chunxu ( Rolling mill bearing) Four row cylindrical roller bearing, as a kind of special bearing steel rolling machinery used, after decades of development, has formed a set of relatively stable technical requirements and design criteria. In the production of rolling mill bearing manufacturer in China a lot, because of each manufacturer the different understanding of the rolling mill bearing and the need of market competition, standardized form practice technical regulations to transcend, caused great difficulties to the user's use and maintenance. Rolling mill in our country in four row cylindrical roller bearings have two sets of current industry standards, JB/T5389. 1 - And JB4039-2005 1985 ( Now there are few manufacturers use) Mill with four row cylindrical roller bearings overall dimensions, within the standards specified in the raceway diameter tolerances of minus tolerance, ( As shown in figure 1 and refer to JB/T5389. 1 - 2005). ； Raceway size tolerance for fixed value determined within different groups radial clearance, processing within the outer raceway size to determine the roller months-moons size tolerance, tolerance of FW value is free size, no tolerance requirements, in the actual production is chaos. This gives the steel mill work roll change caused great difficulties. And manufacturers in order to meet the demands of competition to change the FW value, all of these work caused great difficulty for steel mills in daily work. Figure 1 is shown in figure 1: the current national standards, four row cylindrical roller bearing inner raceway size for rolling mill bearing interchange standard size, that is to say, mill with four row cylindrical roller bearing is the basic shaft system. Mill at work in order to ensure accuracy of rolled products, need to keep changing roller grinding, this requires must four row cylindrical roller bearing inner ring can be used in separation and interchangeable, as a result, the last contact diameter of roller set should be linked with bearing dimension, become the basic size bearing, both mill with four row cylindrical roller bearings should be dominated by base hole system design. At present, in our country has not specialized standard external ring last contact roller diameter FW value of tolerance to make that clear. Although up to now, there is no specific international standard of four row cylindrical roller bearing of FW value tolerance of unified regulation, but the world famous bearing company produces rolling mill bearings are the values of FW swaps as four row cylindrical roller bearing, the first thing to determine the radial clearance in determining the inner raceway machining tolerance, namely the base hole system design. As shown in figure 2 and table delta FW tolerance: figure 2 last contact roller diameter tolerance of FW value as a swap with dimension, take the form of base hole system, but also is the tolerance requirements, FW value of tolerance should be as mill with four row cylindrical roller bearing design, the first thing to do, must be strictly observed, should transcend and change, delta FW tolerance may refer to the table below to choose: base hole system and the basic shaft for the righteous: base hole system: adopt the method of base hole system, consists of outer ring raceway and roller roller movement after the formation of the bearing inner diameter within the last contact FW as a fixed value; Through processing with different size of the inner ring diameter ( di） Values of different groups of bearing factory radial clearance, the method of shaft basis: di bearing inner ring diameter as fixed value; Through processing and choose different size of the outer raceway and roller diameter size of group bearing factory radial clearance method.