SKF 634-2Z Metal Shielded Single Row Deep Groove Ball Bearing 4x16x5mm

The SKF 634-2Z shielded miniature deep groove ball bearing provides rotational support for machinery requiring a 4mm shaft within a 16mm outside bearing diameter. Its 5mm width allows installation in compact bearing seats, while the larger radial cross-section compared with the 624 series provides additional load-carrying capability. The single row deep groove raceways accommodate predominantly radial loads together with axial forces in either direction, within the bearing's rated limits. SKF specifies a basic dynamic load rating of 1.11kN and a basic static load rating of 0.38kN. These figures help engineers evaluate fatigue life and stationary loads in miniature motors, instruments and mechanical drive systems. Despite sharing a 4mm bore and 5mm width, the 634 is not dimensionally interchangeable with the smaller 624 bearing.

The 2Z designation identifies a pressed steel shield on each side of the bearing. Unlike rubber contact seals, these shields do not rub continuously against the inner ring, helping to minimise friction and support high rotational speeds. They retain the factory grease and offer protection against larger particles, although they provide less effective sealing against fine dust and moisture than contact-sealed alternatives. SKF lists a limiting speed of 48,000rpm and a reference speed of 95,000rpm; the limiting speed should not be confused with the reference speed or treated as a guaranteed continuous operating speed. The bearing has normal (CN) radial internal clearance and a sheet metal cage. During installation, use appropriate miniature-bearing fits and apply mounting forces to the ring being fitted rather than through the balls.

Typical Applications:

Miniature electric motors and instrument drives

Compact gear trains and mechanical transmissions

Precision automation and positioning mechanisms

Small pulleys and light-duty guide rollers

Model engineering and miniature rotating assemblies