RHPSuper Precision Angular Contact Ball Bearing Triple Set – 100 mm ID, 180 mm OD, 34 mm Width, 15° Contact Angle, P4, Light Preload, Open

Product Description

What this part is

RHP 7220CTR3ULP4 super precision angular contact ball bearings, supplied as a factory matched triple set. Bore: 100 mm. Outside diameter: 180 mm. Width: 34 mm per bearing, 102 mm across the set. Series: 72, ISO dimension series 02. Single row each, open, straight bore, universally faced. Manufactured in the United Kingdom.

Decoding the designation

Contact Angle: 15°. Cage: TR, machined laminated phenolic resin, outer ring guided. Grouping: 3U, triple set. Preload: Light. Precision Grade: P4, equivalent to EP7, ABEC 7 and ISO Class 4.

What these specs mean in practice

Dynamic Load Rating: 149 kN per bearing. Static Load Rating: 127 kN per bearing. Limiting speed: 12,000 rpm on oil/air lubrication and 7,500 rpm on grease for a single bearing. A 15° contact angle runs faster and carries less thrust than a 25°. P4 holds tighter running accuracy, which lowers runout and vibration in a spindle: inner ring radial runout 5 µm maximum, outer ring radial runout 7.5 µm maximum. The 72 series carries a heavier section than the 70 series at the same bore, giving higher load ratings for the same shaft.

Preload and stiffness

Axial preload for a light-preload pair of this size and angle: 980 N. Axial stiffness at light preload: 137 N/µm. For a light-preload set of three the recommended limiting speed is 0.65 of the single-bearing figure, giving 7,800 rpm on oil/air and 4,875 rpm on grease. Preload is set at manufacture, so no internal clearance value applies.

Quantity and configuration

Three pieces, a factory matched triple set. The set carries a V line on the outer ring outside diameter that fixes the mounting order, and as standard the V points in the direction of maximum axial capacity with load applied to the inner ring. Common triple arrangements are DBD, DFD and DTD.

Mounting data

Inner ring abutment diameter d1: 112 mm minimum. Outer ring abutment diameters D1 and D2: 168 mm and 173 mm maximum. Fillet radii r and r1: 2.5 mm and 1.5 mm minimum. Effective load centre a: 35.7 mm. Lubrication jet pitch circle diameter: 130.6 mm. Internal free volume: 139.2 cm3 per bearing. Maximum recommended operating temperature: 120 °C. Rings and balls: SAE 52100 through-hardened chrome bearing steel. Mass: 3.173 kg (6.99 lb) each, 9.519 kg (20.99 lb) for the set of three.

Interchange guidance

Carton designations: 7220CTR3ULP4, 7220-C-TR-3UL-P4, 7220C TR 3UL P4. NSK 7220CTRDULP4 is the current-scheme equivalent at 15° with the same outer-ring-guided phenolic cage, supplied as a pair. SKF 7220 CD/P4ADGA is a 15° light-preload equivalent. Fafnir 2MM220WI is a 15° equivalent envelope.