RHP7221TDULP4-1/2PRSuper Precision Angular Contact Ball Bearing, Half Pair – 105 mm ID, 190 mm OD, 36 mm Width, P4, Light Preload, Open

Product Description

What this part is

RHP 7221TDULP4-1/2PR super precision angular contact ball bearing. Bore: 105 mm. Outside diameter: 190 mm. Width: 36 mm. Series: 72, ISO dimension series 02. Single row, open, straight bore, universally faced. Manufactured in the United Kingdom.

Decoding the designation

Contact Angle: Not specified. Cage: machined laminated phenolic resin, outer ring guided. Grouping: DU, paired unit. Preload: Light. Precision Grade: P4, equivalent to EP7, ABEC 7 and ISO Class 4. The -1/2PR suffix marks one half of a factory matched pair.

What these specs mean in practice

P4 holds tighter running accuracy than a standard-grade bearing, which lowers runout and vibration in a spindle: inner ring radial runout 5 µm maximum, outer ring radial runout 10 µm maximum. The 72 section is the heavy choice at 105 mm bore, 190 mm outside diameter and 36 mm wide, and carries higher load ratings than the 70 section on the same shaft. Light preload gives the lowest internal friction and heat generation of the four preload classes and the highest permissible speed. Preload is set at manufacture, so no internal clearance value applies.

Quantity and configuration

One bearing, one half of a factory matched light-preload pair. That suits a spindle rebuild where one half of an installed pair needs replacing, and it is the single-piece way into this envelope. Universal face control means the rings are pre-adjusted, so this piece pairs back-to-back, face-to-face or in tandem with another 7221TDULP4 at the marked light preload without ground spacers.

Fitting notes

Inner ring abutment diameter d1: 117 mm minimum. Outer ring abutment diameters D1 and D2: 178 mm and 183 mm maximum. Fillet radii r and r1: 2.5 mm and 1.5 mm minimum. Lubrication jet pitch circle diameter: 137.4 mm. Internal free volume: 165.1 cm3. Recommended shaft fit for P4 at this diameter is a mean interference of 3 µm, and the locating housing fit a mean clearance of 7 µm. The high point of radial runout is marked with a burnished spot on the inner ring face and a V line on the outer ring outside diameter, and the V line also shows the direction of the contact angle. Grease fill is 30 per cent of internal volume at low and medium speed, 20 per cent above 60 per cent of maximum speed. Maximum recommended operating temperature: 120 °C. Rings and balls: SAE 52100 through-hardened chrome bearing steel. Mass: 3.777 kg (8.33 lb).

Interchange guidance

Carton designations: 7221TDULP4-1/2PR, 7221TDULP4, 7221-T-DUL-P4, 7221 T DUL P4, 7221TDUEP7, 7221B. In the 72 envelope at 105 mm bore the 15° executions are SKF 7221 CD/P4ADGA, FAG B7221-C-T-P4S-DUL, Fafnir 2MM221WI-DUL and NSK 7221CTRDULP4; the 25° executions are SKF 7221 ACD/P4ADGA, FAG B7221-E-T-P4S-DUL, Fafnir 3MM221WI-DUL and NSK 7221A5TRDULP4.