The Design of Rolling Bearing Mountings

104Roll bearings of afour-high cold rolling stand for aluminiumOperating dataBack-up rolls: roll diameter 1,525 mmroll body length 2,500 mmWork rolls: roll diameter 600 mmroll body length 2,500 mmMaximum rolling load 26,000 kNMaximum rolling speed 1,260 m/minSelection of the back-up roll bearings (fig. 104a)Radial bearingsThe high radial loads are best accommodated, in a limitedmounting space and at high speeds, by cylindricalroller bearings. One four-row cylindrical roller bearingFAG 527048 (dimensions 900 x 1,220 x 840 mm) ismounted at each roll end. The bearings feature pintypecages and reach a dynamic load rating of C =31,500 kN.The increased radial clearance C4 is required as the innerrings are fitted tightly and heat up more in operationthan the outer rings.Machining tolerances:Roll neck +0.350 / +0.440 mm, chock to H7.Thrust bearingsSince thrust loads in strip rolling stands are low, thrustbearings are used that are small compared to the radialbearings. The back-up roll is supported at both ends bya double-row tapered roller bearing FAG 531295A (dimensions400 x 650 x 240 mm) with a dynamic loadrating C of 3,450 kN.Machining tolerances: Shaft to f6.The cups are not supported radially; axially, they areadjusted by means of helical springs.104a: Back-up roll mounting of a four-high cold rolling stand for aluminium (identical bearing arrangements at drive end and operating end)FAG 146