A rolling bearing for lengthwise movement along a shaft comprised of an outer sleeve having a plurality of races therein for rolling bearings, a cage being provided to guide the rolling bearings. A sealing ring is provided at each end of the assembly, the sealing ring having lips extending radially inwardly to contact the shaft. The sealing lips are thin and elastically bendable, and are mounted to enable bowing thereof into free spaces on opposite sides thereof, depending upon direction of lengthwise movement of the shaft. As a consequence, for small movements of the shaft, the sealing lips cling to the shaft and become bulged, rather than sliding along the shaft.