4208AV Nilos Ring for 4208 Series Bearings 40x72.7x3mm

Nilos AV Sealing Rings: A Nilos ring that seals the outer roller bearing ring is described as an AV type. They are used to provide sealing for bearings that have no shields or seals. A Nilos ring of suitable dimensions can be installed so that the Nilos ring fully encloses the open area of the bearing.
Nilos rings are required in particular installations where excess dirt or debris may be present that could penetrate up to the bearing, if some further mechanical protection is required or if condensation is formed.
Sealing is produced by placing the sealing edge of the Nilos ring under light pressure at the outer bearing ring so that it rubs to a greater or lesser depth into the hardened roller bearing ring. The fine labyrinth produced as a result prevents the leakage of grease and the penetration of dirt into the bearing. If sealing is required around the inner raceway then a JV type Nilos ring should be used.