Ball bearing assembly for rotatably supporting a belt support roll on an axle comprising a pair of bearing rings having confronting spaced apart sections defining inner and outer raceways disposed at an angle to the normal axis for a plurality of balls. The inner bearing ring has a radial outwardly directed flange serving as means to secure the bearing to the roll casing and a flange extending radially inwardly from the race confronting a sleeve mounted on the axle. The outer bearing ring has an annular ring flange facing inwardly to the bearing axle confronting the radial flange of the inner bearing ring and terminating in an annular shoulder running axially for fastening to the axle. A sleeve circumscribes the axle and has a radially outwardly directed rib which forms with the inner bearing ring an annular chamber for a sealing agent. A seal with flocked fibers is interposed between the confronting inner flanges of the inner and outer bearing rings.