Z-shields are used to cover ball bearings. Depending on requirements, plastic ball bearings can be covered on one or both sides. In contrast to steel ball bearings, sealing is not necessary in most cases, as the plastic ball bearing is used without lubrication.
The integration of Z-shields prevents the penetration of coarse dirt particles into the bearing. Dirt particles can iimpair the running properties of the ball bearing and lead to increased wear.
Z-shields are integrated into SMG plastic ball bearings by inserting a groove in the outer ring.