NSK7919A5TRDULP4YSuper Precision Angular Contact Bearing — 95 mm ID, 130 mm OD, 18 mm Width, Open, 25° Contact Angle, Light Preload, 2 Pcs

Product Description

What this part is

NSK 7919A5TRDULP4Y, a universally matchable super-precision angular contact ball bearing, supplied as two pieces. Bore: 95 mm. Outside diameter: 130 mm. Width: 18 mm per bearing. Series: 71900 (ISO 719 dimension series). Contact angle: 25°. Precision: P4Y. Country of origin as recorded: United Kingdom.

Decoding the designation

7919 is the ISO 719 dimension series at bore code 19, a thinner section than a 7019 on the same bore. A5: 25° contact angle. TR: outer-ring-guided phenolic resin cage, rated to 120 °C. DU: duplex universal matching, so any two bearings of this designation pair without a spacer. L: light preload. P4Y: ISO Class 4 running accuracy with special bore and outside diameter tolerances, giving closer shaft location and lower running vibration.

Ratings and speed

Basic dynamic load rating Cr: 50.0 kN. Basic static load rating C0r: 45.5 kN. Permissible axial load Pa: 35.0 kN. Limiting speed: 8,900 rpm on grease, 13,400 rpm on oil or oil-air. Effective load centre a: 35.2 mm. Axial rigidity at light preload: 261 N per micrometre. Preload force at light: 512 N.

What these specs mean in practice

A 25° contact angle carries more thrust and gives higher axial rigidity than the 15° C variant, at a lower speed ceiling. At light preload this bearing reaches 261 N per micrometre of axial rigidity on a 95 mm bore, which is roughly twice the figure a 15° bearing of the same section returns. The outer-ring-guided phenolic cage holds its running position at high dmn values, which is why it appears on machine-tool spindles rather than a ball-guided polyamide cage.

Quantity and configuration

Two pieces, universally matched, 36 mm total width as a pair. Back-to-back carries thrust in both directions across a wide load-centre spread and takes moment loads. Face-to-face narrows that spread and suits housings of lower accuracy. Tandem doubles thrust capacity in one direction. Measured axial clearance in a back-to-back or face-to-face pair at light preload: minus 8 micrometres.

Fitting notes

Shaft abutment diameter da: 102 mm minimum. Housing abutment Da: 123 mm maximum, Db: 125 mm maximum. Ring chamfer r: 1.1 mm minimum, r1: 0.6 mm minimum. Shaft fillet radius ra: 1 mm maximum, rb: 0.6 mm maximum. Grease charge as published: 3.3 g per bearing. Both faces are open.

Interchange guidance

Same-specification equivalents: SKF 71919 ACD/P4ADGA and FAG B71919-E-T-P4S-DUL, both 25° phenolic-cage duplex pairs at light preload on the identical envelope. NSK 7919CTRDULP4Y is the 15° bearing on the same envelope — a related size rather than a substitution, because contact angle sets the thrust-to-speed balance.