SKF 628/9-2Z Metal Shielded Single Row Deep Groove Ball Bearing 9x17x5mm

The SKF 628/9-2Z shielded miniature deep groove ball bearing provides compact rotational support where a 9mm shaft must fit within a 17mm outside diameter. Its 5mm width allows installation in narrow housings, while the single row deep groove raceways support radial loads together with limited axial loads in either direction. The 628/9 has the same bore and outside diameter as the thinner 618/9 series but requires an additional millimetre of axial space. This distinction matters when checking shaft shoulders, housing recesses and retaining components. SKF specifies a limiting speed of 43,000rpm for the double-shielded version, making the 2Z arrangement relevant to applications where reduced friction is a priority.

The 2Z suffix identifies a non-contact metal shield on each side, rather than the rubber contact seals used on the 2RS1 version. These shields help retain factory-applied grease and protect against larger particles without producing the same degree of rubbing friction as contact seals. However, they provide less protection against fine dust, water and other contaminants than rubber contact seals. The bearing has normal (CN) radial internal clearance and a sheet metal cage. Its miniature construction requires controlled mounting practices, particularly when fitting the rings onto shafts or into housings. Always apply mounting force to the ring being fitted and confirm that the original equipment specification calls for a shielded bearing rather than a contact-sealed alternative.

Typical Applications:

Precision measuring and instrument assemblies

Miniature guide rollers in clean environments

Small high-speed mechanical drive systems

Compact automation and positioning mechanisms

Light-duty pulley and shaft support assemblies