NSK7209A5TYDULPA1Matched Duplex Pair Angular Contact Ball Bearings – Straight Bore, 45 mm ID, 85 mm OD, 19 mm Width Each, Open, 25° Contact Angle, Polyamide Cage, Light Preload, 2 Pcs

Product Description

What this part is

NSK 7209A5TYDULPA1 angular contact ball bearings supplied as a matched duplex pair. Each bearing is 45 mm bore, 85 mm outside diameter, 19 mm width, single row, steel balls, polyamide cage, open on both faces, straight bore.

Decoding the designation

72 is the ISO dimension series and 09 is the bore code — 9 × 5 = 45 mm. In the NSK scheme A5 is a 25° contact angle and TY is a ball-guided polyamide cage. DU marks a duplex set, flush-ground as a pair, and the L calls light preload. The carton’s alternate designation 7209E reads the same 25° angle in the European scheme.

What these specs mean in practice

A 25° contact angle carries markedly more thrust than a 15° ring of the same envelope and gives up some speed for it. The ball-guided polyamide cage runs quietly, damps well and is rated to 120 °C, which sets the temperature ceiling for the pair. Light preload keeps friction and heat generation down while still removing all play from the bearing set.

Thrust direction and arrangement

Each row carries thrust in one direction only. Set back-to-back or face-to-face, the duplex pair locates the shaft in both directions and resists moment loads; set in tandem, the pair remains one direction and roughly doubles the thrust capacity of a single bearing. Duplex faces are ground so that the pair clamps up to the intended preload with no shim stack.

Quantity and configuration

2 Pcs. One matched duplex pair, light preload class. Supplied without spacers.

Fitting notes

Duplex bearings are supplied as a matched set and stay together as a set, with the face marks aligned to reproduce the ground arrangement. Both rings are clamped fully against their abutments so the preload arrives at the ground value; interference on the shaft and housing seats adds to it, so those seats are ground to spindle tolerances rather than to nominal 45 mm and 85 mm.

Interchange guidance

Same-envelope 25° duplex-light equivalents are the FAG B7209-E-T-DUL, the SKF 7209 ACD/DGA and the Timken Fafnir 3MM209WI-DUL. Those carry phenolic cages where this pair carries polyamide, so they match on angle, arrangement and preload rather than on cage material. A 7209C or 7209A of this envelope carries a different contact angle and is a related size.