Eight roller rolling back lining bearing inner ring - bearing damage cause analysis knowledge

A cold rolled sheet plant mill equipment using the eight roller rolling five consecutive layout, mill use backing bearings for 3 pl130m. Backing bearing is a kind of special thick outer ring, use in the form of group is installed in the stillness of the shaft become more supporting roller of roller mill rolling bearing. Backing bearings eliminate radial clearance after the end face of H value of 0. 005 mm, bearing factory is a factory group number, do not disturb the original number of group bearing when installation, in the middle of the bearings on each shaft H value maximum, adjacent bearing outside diameter to 0. 002 mm, the whole bearing beat control in 0. Less than 005 mm, each batch of bearing clearance at 0. 04mm- 0. 07mm。 The bearing is 5 sets of bearings for a group of installed on a spindle, the damage roll under 5 # frame, bearing damage in the both sides of the bearing. Bearing lubrication with 220 # gear oil lubrication, cooling, cooling use emulsion rolling product thickness is 0. 5 mm, width is 620 mm and 630 mm, 5 # mill 600 RPM ( The finished sheet frame) , reduction in 3 to 5 between, bearing damage form below; Figure a figure 2 figure it is the group on both sides of the backing bearing inner ring damage form, on both sides of the damaged condition, the same damage location is in figure 2 # 1 and # 5 bearing inner ring. Figure 2 is a set of backing bearings are assembled state. The scene to understand the billet bearing a total of 100 sets, the arrival of the damaged bearing on 15 days, in the 1 # and 5 # inner ring load area in a large area of spalling, intermediate 2 # 3 # 4 # bearing inner ring no peeling, other bearing online using 2 rounds did not appear as a form of damage, the scene to understand the backing bearings with spindle has been no check. Rolling plate width is different, each backing on the backup roll bearing number is 3 ~ 7. For the requirement of rolling plate edge, rolling strip shape adjustment result is every backup roll on mileage from both ends of the second set of bearing load, the largest commonly known as 'the phenomenon of cat ears'. The force difference how dozens to several times. The more a number of backup roll bearing the force difference is smaller. So the second and the fourth set of bearing the most easily damaged. This kind of structural problem is inevitable. A better solution is in the process of bearing manufacture and installation, matching each backup roll on several sets of bearing the cross section of high differential values of 'H', each other requirements in the middle of the slightly several microns. For example in the third set of bearing 'H' slightly larger, a decline of a few microns on both sides of the bearing H. Through the understanding of judgment on the damaged 1 # and 5 # bearing inner ring is due to the core shaft deflection error as the main factors causing large area of spalling, suggested that the spindle is measured on a regular basis, repair.