RHPB7211X2TADULEP7Super Precision Angular Contact Ball Bearing Duplex Pair 55x100x21 mm 15° Contact Angle ABEC 7 Light Preload Phenolic Cage

Product Description

What this part is

RHP B7211-X2-TA-DUL-EP7, a super precision angular contact ball bearing supplied as a matched duplex pair. Bore: 55 mm (2.1654 in). Outside Diameter: 100 mm (3.9370 in). Overall Width: 21 mm (0.8268 in) per bearing. Total Width: 42 mm (1.6535 in) for the mounted pair. Series: ISO 72, dimension series 02. Rolling Elements: steel balls, one row per bearing. Closure Type: open both faces.

Decoding the designation

Contact Angle: 15°, from the RHP B-series code X2. Cage Material: laminated phenolic, from the T. Arrangement: duplex, from the DU. Preload: light, from the L. Precision Class: EP7, ABEC 7, ISO Class 4. Base Number: 7211, bore code 11 giving a 55 mm bore. The Fafnir cross on the carton, 2MM211WI-DUL, agrees on the angle.

Published specifications

Dynamic Load Rating: 53.0 kN (11,914 lbf) per bearing. Static Load Rating: 40.0 kN (8,992 lbf) per bearing. Limiting Speed: 23,000 r/min oil/air and 14,200 r/min grease for a single bearing; a light-preload back-to-back pair runs at 0.80 of those figures. Axial Preload: 490 N. Axial Stiffness: 181 N/µm for the pair. Effective Load Centre: 20.9 mm. Item Weight: 2.66 lb (1.206 kg) for the pair. Maximum Operating Temperature: 120 °C. Bore Type: straight. Internal Clearance: N/A, the set is preload-adjusted. Lubricant: grease or oil.

Mounting dimensions

Shaft Abutment Diameter d1: 64 mm minimum. Housing Abutment Diameter D1: 91 mm maximum. Outer Ring Abutment Diameter D2: 94 mm maximum. Bearing Fillet Radius r: 1.5 mm minimum. Secondary Fillet Radius r1: 1.0 mm minimum. Internal Volume: 27.8 cm³ per bearing. Pitch Circle Diameter Of Lubrication Jets: 72.0 mm.

What these specs mean in practice

A 15° contact angle favours speed and radial stiffness; the RHP X3 variant at 25° trades speed for thrust capacity. Each row takes thrust in one direction, so the duplex pair locates the shaft in both. Light preload of 490 N gives 181 N/µm of axial stiffness while keeping running torque and heat generation low. The rings are universally faced, so the pair can be stacked back-to-back, face-to-face or in tandem at the same preload value. The laminated phenolic cage is outer-ring guided, light and quiet at speed, and rated to 120 °C.

Quantity and configuration

Unit Quantity: 2 Pcs, one matched duplex pair. Mounting Arrangement: universally faced, DB, DF or DT.

Interchange guidance

Same-spec 15° light-preload ABEC 7 duplex equivalents in other schemes: the ISO form 7211C-P4-DUL, Fafnir 2MM211WI-DUL, NSK 7211CTRDULP4, SKF 7211 CD/P4A. The RHP B7211-X3 at 25°, and the medium and heavy preload forms, share the 55 x 100 x 21 mm envelope and are related sizes.