NSK7218ATDBC9P5Angular Contact Ball Bearing – 90 mm ID, 160 mm OD, 30 mm Width, Open, 30° Contact Angle, Heavy Preload, Back-to-Back Matched Pair.

Product Description

What this part is

NSK 7218ATDBC9P5 super-precision angular contact ball bearing, 90 mm bore × 160 mm outside diameter × 30 mm width. Series: 7200. Contact Angle: 30°. Precision Class: P5, ABEC 5. Preload: heavy. Straight bore, open on both faces. Supplied as a back-to-back matched pair, 2 pieces.

Decoding the designation

Base Number: 7218A. A: 30° contact angle. TY: ball-guided cage. DB: back-to-back matched arrangement, 2 bearings. DUH: duplex universally ground set at heavy preload. C9: preload class. P5: ISO Class 5, ABEC 5. The carton also carries 7218 A T DB C9 P5 and 7218 A TY DUH P5.

What these specs mean in practice

A 30° contact angle is the highest-thrust angle in the standard super-precision range, and it trades speed for axial capacity. Heavy preload raises axial rigidity and cuts axial play, at the cost of running temperature and speed. Basic Dynamic Load Rating: 142 kN per bearing. Basic Static Load Rating: 96.5 kN per bearing. Limiting Speed: 6,000 rpm on grease, 8,000 rpm on oil or oil-air. Mass: 2.23 kg per bearing.

Quantity and configuration

Two bearings, ground and matched as a back-to-back set at heavy preload. Total width of the pair: 60 mm. Preloaded sets are supplied without a running clearance. Bearing Material: high carbon chrome steel.

Fitting notes

The pair is fitted as a unit, marked faces together, with the inner rings clamped on the shaft and the outer rings clamped in the housing so the ground offset holds the heavy preload.

Interchange guidance

SKF 7218 ACD/P5 DGC covers the same envelope at heavy preload. Fafnir 3MM218WI is the same envelope at a 25° contact angle, so it is a related size. A 7218C on the same envelope carries a 15° contact angle and is a related size.