SKF deep groove ball bearings with shields are primarily intended for applications where the inner ring rotates. Shields are fitted in the outer ring and do not make contact with the inner ring, but form a narrow gap with it. Shields are made of sheet steel.
Depending on the SKF bearing design, series and size, SKF supplies shields in different designs. Shields identified by the designation suffix Z typically have an extension in the shield bore to form a long, narrow gap with the inner ring shoulder. Some shields do not have the extension.
fig. 1 - Shield with extension in the shield bore
fig. 2 - Shield without extension in the shield bore