The lubricant is passed through a supply opening which opens axially into the hollow roller. The roller has a permeable cylinder sleeve covered by a perforated jacket of soft likewise permeable material such as felt. The perforations may be achieved by holes drilled or punched out and may be added radially like chords. The perforations can run inclined from inside outwards and preferably make up between 5 and 10% of the surface.
