Abstract: With the rapid development of cold rolling mill technology, especially the rapid development of general carbon steel six-roller mill, the comprehensive and practical performance of cold rolling mill bearings is put forward higher requirements. The selection of roll system bearings of working roll and middle roll of domestic rolling mill is analyzed as follows.

Structure of the one:

Four row cylindrical bearings plus positioning bearings

In the roller system, four columns are used as radial bearing, and the double-row angular contact ball bearing bears the axial load to locate the bidirectional axial displacement of the roller, which is the most common configuration in the selection of six-roller single frame at present.

Configuration analysis:

1, four column cylindrical bearing components are less, the parts are regular ring parts easy to process, the precision is easy to control, compared with other series of bearing has the characteristics of high limit speed bearing capacity, and has a high degree of interchangeability.

2. Bearing inner ring interference is installed separately in the roller diameter, and the outer ring assembly is installed in the bearing box. After loading the roller diameter, the outer ring assembly and the inner ring can be separated, and the installation is quick and convenient.

3. It can be separated after loading the roller diameter, and the bearing box can be removed to directly check the use status of each bearing parts (inner ring, outer ring, rolling body, cage).

4, the inner diameter and shaft diameter interference fit, in case of accident failure such as: bearing burn or lock can effectively protect the roller diameter.

5. The inner ring or outer component can be fixed separately. The bearing can be used only by replacing the inner ring or outer component, avoiding unnecessary replacement of undamaged parts.

6. Double row angular contact ball bearings are required to be positioned separately to limit the axial displacement of the rolling roll.
Summary: This configuration can meet the speed and load requirements of the rolling mill. However, with the increase of the service life of the equipment, the decrease of the accuracy of the equipment and the increase of the axial load, the damage of the positioning double-row angular contact ball bearings, the wear of the early cage and the loss of copper powder often occur. Intermediate cage fracture; In the late stage, the positioning bearing is uncertain or short time burning problem. During configuration, special attention should be paid to the contact Angle, cage structure, strength and so on.

Structure of the two:
Four row tapered bearing

In the roller system, four rows of taper bearings are used as radial and axial joint load bearing, which can bear radial load and hold the bidirectional axial limit of the roller. This is the structure configuration that the selection of six-roller single frame is less, and the selection of six-roller five-roll rolling and six-roll rolling is more.

Configuration analysis:
1, four row taper bearing parts, inner and outer ring and rolling body are conical surface, high processing accuracy is required, parts are marked with part number, serial number, high installation requirements, parts have a unique installation position.

2. The whole set of bearing is installed into the body, and the bearing can not be separated after loading into the box. The inner ring and the shaft are usually clearance fit, and the installation is quick and convenient, and the fast loading and unloading can be realized directly.

3. The bearing cannot be separated after being loaded into the box. After the bearing box is removed from the roller diameter, the service condition of each bearing part (inner ring, outer ring, rolling body, cage) cannot be directly checked. Need to further remove the bearing from the box body, can be intuitive inspection and cleaning steps.

4, the inner diameter and shaft diameter clearance, in the event of an accident, such as: bearing burn or lock when the roller diameter and bearing inner ring direct wear, easy to cause damage to the roller diameter.

5, bearing parts can not be exchanged, parts damage, the whole set of bearings need to be scrapped, but during the use, can be bearing grinding ring to maintain the original clearance of the bearing, to ensure the use of bearing accuracy.

6, at the same time as the radial and axial joint bearing bearing, that is, bear radial load and both the two-way axial limit roller, can realize the independent use of bearings, can remove the use of positioning bearings.

Summary: THIS CONFIGURATION CAN BETTER MEET THE LOAD REQUIREMENTS OF ROLLING MILL SYSTEM, BUT THE LIMIT SPEED IS SLIGHTLY LOWER, WHICH IS ABOUT 70% OF THE LIMIT SPEED OF the SAME size series cylindrical BEARINGS. Similarly, with the increase of the service life of the equipment, the decrease of the accuracy of the equipment and the increase of the axial load, there are often single or double row bearing burning problems, as well as uncertain or short time burning problems.

In the configuration, special attention should be paid to the cage structure and the cage protrusion with the gland; The size of the small mouth matches the size of the shaft shoulder diameter; The fit of the septum ring and the end face of the inner ring.

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