NSK7020CTDBCP18PA7Super Precision Angular Contact Bearing — 100 mm ID, 150 mm OD, 24 mm Width, Open, 15° Contact Angle, Back-to-Back DB Set, 2 Pcs

Product Description

What this part is

NSK 7020CTDBCP18PA7, a super-precision angular contact ball bearing matched back-to-back, supplied as two pieces. Bore: 100 mm. Outside diameter: 150 mm. Width: 24 mm per bearing, 48 mm as a pair. Series: 7000 (ISO 70 dimension series). Contact angle: 15°. Country of origin as recorded: Japan.

Decoding the designation

7020 is the ISO 70 dimension series at bore code 20. C: 15° contact angle. T: outer-ring-guided phenolic resin cage, rated to 120 °C. DB: back-to-back matched pair, ground as a set at the factory. CP18: special preload, made to order. PA7: ABEC 7 class accuracy.

Ratings and speed

Basic dynamic load rating Cr: 95.0 kN. Basic static load rating C0r: 77.0 kN. Permissible axial load Pa: 49.0 kN. Limiting speed: 9,200 rpm on grease, 14,000 rpm on oil or oil-air. Effective load centre a: 28.7 mm. f0: 16.0.

What these specs mean in practice

A 15° contact angle favours speed and radial rigidity over thrust capacity; a 25° bearing on the same envelope carries more thrust and turns slower. Back-to-back mounting sets the two effective load centres wide apart, which is what gives a DB pair its moment stiffness and puts it at the front bearing position on a machine-tool spindle. The outer-ring-guided phenolic cage holds its running position at high dmn values, and is cleared to a 2.8 million dmn limit against 1.2 to 1.4 million for a ball-guided polyamide cage.

Quantity and configuration

Two pieces, factory-matched as a back-to-back set at a special preload. Total width 48 mm. The pair carries thrust in both directions and takes moment loads.

Fitting notes

Shaft abutment diameter da: 109 mm minimum. Housing abutment Da: 141 mm maximum, Db: 144 mm maximum. Ring chamfer r: 1.5 mm minimum, r1: 1 mm minimum. Shaft fillet radius ra: 1.5 mm maximum, rb: 0.8 mm maximum. Grease charge as published: 6.7 g per bearing. Both faces are open. A back-to-back pair is fitted with the wide faces of the outer rings together.

Interchange guidance

NSK 7020CTYDBP4B is the same envelope and contact angle with a ball-guided cage. NSK 7020A5TDBP4 is the 25° bearing on the same envelope. Both are related sizes rather than substitutions: cage guidance sets the speed ceiling and contact angle sets the thrust-to-speed balance. The searchable forms of this designation include 7020CTDBCP18PA7, 7020-CT-DB-CP18-PA7 and 7020 CT DB CP18 PA7.