Selection and Usage of Rolling Mill Bearings

Jun 15, 2022

The roll bearing of the rolling mill is very important and is the core component for the normal operation and normal rotation of the roll. The working environment of rolling mill bearings requires it to have large bearing capacity, strong impact resistance, and unstable working temperature, so it is necessary to choose suitable bearings to reduce the downtime of rolling mill failures. However, some customers still do not know how to choose suitable bearings. Today, Luoyang FV will explain how to choose suitable bearings for rolling mills.

Selection of rolling mill bearings

Four-row cylindrical roller bearings: Under the same external dimensions, multi-row cylindrical roller bearings can withstand larger loads than double-row cylindrical roller bearings, and can adapt to higher working speeds. However, it cannot bear the axial load, so when choosing four-row cylindrical roller bearings, needle roller bearings, etc., it is necessary to match the thrust bearing to bear the axial load, so that the multi-row cylindrical roller bearing can bear the radial load.

The roller of the four-row tapered roller bearing has an included angle with the horizontal during installation, so it can bear both radial load and axial load.

The double row radial spherical roller bearing also has a certain angle with the horizontal during installation, which can bear both radial load and small axial load, and has the characteristics of self-aligning.

The selection of roll bearings should not only be based on the size and structure of the roll, but also consider the load of the bearing. The Load, in particular, is the most important factor in determining bearing life. Calculating the lifespan is more complicated, the easiest way is to consult our engineers, who will provide you with suitable suggestions and options. After selecting the appropriate bearing, the next step is the installation of the roll neck bearing.

Installation of Roll Neck Bearings

During the installation of the multi-row cylindrical roller bearing, in order to maintain a high degree of coaxiality, the inner ring of the bearing is heated in the oil tank to make the inner hole of the inner ring and the roll diameter of the roller to be hot-pressed and assembled. After completion, the final size of the bearing inner ring raceway is ground based on the roll body to improve the radial rotation accuracy.

When installing the four-row tapered roller bearing, first put the whole set of bearings into the bearing seat, and then put the roll neck of the roll into the inner hole of the bearing. Therefore, the roll neck and the inner hole of the bearing can only use clearance fit, and at the same time, oil grooves should be provided on the surface of the inner hole of the bearing, the end face of the inner ring, the surface of the roll neck, and the end face of the axial inner retaining ring.

When installing double-row spherical roller bearings, the matching between the inner hole of the bearing and the shaft adopts a clearance fit.

Properly use and maintain roll bearings

When the working time of the bearing reaches 1/3 of the service life, a comprehensive inspection and cleaning must be carried out, and the internal clearance of the bearing must be checked. When it is greater than twice the original clearance, it should be adjusted; when the bearing outer ring is cleaned, after that, rotate the outer ring of the bearing by 90°, that is, replace the load-bearing area and then assemble it.

For the roll bearing seat, check regularly, if it does not meet the original design requirements, it should be replaced in time.

Strictly implement the maintenance procedures for cleaning bearings.

In general, the design service life of the work roll bearing is 3000~5000h, but in fact it is far from reaching this target value. In order to avoid or reduce the damage of the bearing, some necessary measures should also be taken to improve the service life of the roll bearing: for example, rationally use the bending force, improve the bearing capacity of the roll bearing, and improve the lubrication conditions of the roll bearing, etc.